WorldWideScience

Sample records for psd-95 postsynaptic density-95

  1. Posttranslational Modifications Regulate the Postsynaptic Localization of PSD-95.

    Science.gov (United States)

    Vallejo, Daniela; Codocedo, Juan F; Inestrosa, Nibaldo C

    2017-04-01

    The postsynaptic density (PSD) consists of a lattice-like array of interacting proteins that organizes and stabilizes synaptic receptors, ion channels, structural proteins, and signaling molecules required for normal synaptic transmission and synaptic function. The scaffolding and hub protein postsynaptic density protein-95 (PSD-95) is a major element of central chemical synapses and interacts with glutamate receptors, cell adhesion molecules, and cytoskeletal elements. In fact, PSD-95 can regulate basal synaptic stability as well as the activity-dependent structural plasticity of the PSD and, therefore, of the excitatory chemical synapse. Several studies have shown that PSD-95 is highly enriched at excitatory synapses and have identified multiple protein structural domains and protein-protein interactions that mediate PSD-95 function and trafficking to the postsynaptic region. PSD-95 is also a target of several signaling pathways that induce posttranslational modifications, including palmitoylation, phosphorylation, ubiquitination, nitrosylation, and neddylation; these modifications determine the synaptic stability and function of PSD-95 and thus regulate the fates of individual dendritic spines in the nervous system. In the present work, we review the posttranslational modifications that regulate the synaptic localization of PSD-95 and describe their functional consequences. We also explore the signaling pathways that induce such changes.

  2. Arc Requires PSD95 for Assembly into Postsynaptic Complexes Involved with Neural Dysfunction and Intelligence

    Directory of Open Access Journals (Sweden)

    Esperanza Fernández

    2017-10-01

    Full Text Available Arc is an activity-regulated neuronal protein, but little is known about its interactions, assembly into multiprotein complexes, and role in human disease and cognition. We applied an integrated proteomic and genetic strategy by targeting a tandem affinity purification (TAP tag and Venus fluorescent protein into the endogenous Arc gene in mice. This allowed biochemical and proteomic characterization of native complexes in wild-type and knockout mice. We identified many Arc-interacting proteins, of which PSD95 was the most abundant. PSD95 was essential for Arc assembly into 1.5-MDa complexes and activity-dependent recruitment to excitatory synapses. Integrating human genetic data with proteomic data showed that Arc-PSD95 complexes are enriched in schizophrenia, intellectual disability, autism, and epilepsy mutations and normal variants in intelligence. We propose that Arc-PSD95 postsynaptic complexes potentially affect human cognitive function.

  3. Arc Requires PSD95 for Assembly into Postsynaptic Complexes Involved with Neural Dysfunction and Intelligence.

    Science.gov (United States)

    Fernández, Esperanza; Collins, Mark O; Frank, René A W; Zhu, Fei; Kopanitsa, Maksym V; Nithianantharajah, Jess; Lemprière, Sarah A; Fricker, David; Elsegood, Kathryn A; McLaughlin, Catherine L; Croning, Mike D R; Mclean, Colin; Armstrong, J Douglas; Hill, W David; Deary, Ian J; Cencelli, Giulia; Bagni, Claudia; Fromer, Menachem; Purcell, Shaun M; Pocklington, Andrew J; Choudhary, Jyoti S; Komiyama, Noboru H; Grant, Seth G N

    2017-10-17

    Arc is an activity-regulated neuronal protein, but little is known about its interactions, assembly into multiprotein complexes, and role in human disease and cognition. We applied an integrated proteomic and genetic strategy by targeting a tandem affinity purification (TAP) tag and Venus fluorescent protein into the endogenous Arc gene in mice. This allowed biochemical and proteomic characterization of native complexes in wild-type and knockout mice. We identified many Arc-interacting proteins, of which PSD95 was the most abundant. PSD95 was essential for Arc assembly into 1.5-MDa complexes and activity-dependent recruitment to excitatory synapses. Integrating human genetic data with proteomic data showed that Arc-PSD95 complexes are enriched in schizophrenia, intellectual disability, autism, and epilepsy mutations and normal variants in intelligence. We propose that Arc-PSD95 postsynaptic complexes potentially affect human cognitive function. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  4. PSD95 gene specific siRNAs attenuate neuropathic pain through modulating neuron sensibility and postsynaptic CaMKIIα phosphorylation.

    Science.gov (United States)

    Le, Shen; Xu, Li; Wen, Chen; Li, Xu; Wei, Liu; Xue-rong, Yu; Yu-guang, Huang

    2011-12-01

    To observe the effects of PSD95 gene specific siRNAs on neuropathic pain relief, neuron viability, and postsynaptic calcium/calmodulin-dependent protein kinase IIα (CaMKIIα) phosphorylation in vitro and in vivo. Gene-specific siRNAs of rat PSD95 were synthesized chemically for transfection. Adult male Sprague-Dawley (SD) rats were randomly divided into 3 groups: naïve group (n=6), sham group (n=6), and sciatic nerve chronic constriction injury (CCI) group (n=24). The CCI group was further divided into 4 groups (n=6 in each group), which were pretreated with normal saline, transfection vehicle, negative control siRNAs, and PSD95 gene specific siRNAs respectively. All the subgroups received corresponding agents intrathecally for 3 days, started one day before the CCI of sciatic nerve. Both mechanical allodynia and thermal hyperalgesia were measured on post-operative day 3 and 7. PSD95 gene silenced NG108-15 cells were further stimulated by glutamate, with the cell viability and the expression/phosphorylation of CaMKIIα measured by MTT cell proliferation assay and Western blot, respectively. The siRNAs decreased PSD95 mRNA level significantly both in vivo and in vitro. Neuropathic pain rats pretreated with PSD95 gene specific siRNAs exhibited significant elevation in the mechanical withdrawal threshold and paw withdrawal thermal latency, without affecting the baseline nociception. PSD95 gene silencing enhanced neuronal tolerance against the glutamate excitotoxicity, meanwhile the phosphorylation of CaMKIIα Thr286 was attenuated. Pre-emptive administration of PSD95 gene specific siRNAs may attenuate the central sensitization CaMKIIα-related signaling cascades, leading to the relief of neuropathic pain.

  5. Postsynaptic density-95 scaffolding of Shaker-type K⁺ channels in smooth muscle cells regulates the diameter of cerebral arteries.

    Science.gov (United States)

    Joseph, Biny K; Thakali, Keshari M; Pathan, Asif R; Kang, Eunju; Rusch, Nancy J; Rhee, Sung W

    2011-11-01

    Postsynaptic density-95 (PSD95) is a 95 kDa scaffolding molecule in the brain that clusters postsynaptic proteins including ion channels, receptors, enzymes and other signalling partners required for normal cognition. The voltage-gated, Shaker-type K(+) (K(V)1) channel is one key binding partner of PSD95 scaffolds in neurons. However, K(V)1 channels composed of α1.2 and α1.5 pore-forming subunits also are expressed in the vascular smooth muscle cells (cVSMCs) of the cerebral circulation, although the identity of their molecular scaffolds is unknown. Since α1.2 contains a binding motif for PSD95, we explored the possibility that cVSMCs express PSD95 as a scaffold to promote K(V)1 channel expression and cerebral vasodilatation. Cerebral arteries from Sprague-Dawley rats were isolated for analysis of PSD95 and K(V)1 channel proteins. PSD95 was detected in cVSMCs and it co-immunoprecipitated and co-localized with the pore-forming α1.2 subunit of the K(V)1 channel. Antisense-mediated knockdown of PSD95 profoundly reduced K(V)1 channel expression and suppressed K(V)1 current in patch-clamped cVSMCs. Loss of PSD95 also depolarized cVSMCs in pressurized cerebral arteries and induced a strong constriction associated with a loss of functional K(V)1 channels. Our findings provide initial evidence that PSD95 is expressed in cVSMCs, and the K(V)1 channel is one of its important binding partners. PSD95 appears to function as a critical 'dilator' scaffold in cerebral arteries by increasing the number of functional K(V)1 channels at the plasma membrane.

  6. Human LRRK2 G2019S mutation represses post-synaptic protein PSD95 and causes cognitive impairment in transgenic mice.

    Science.gov (United States)

    Adeosun, Samuel O; Hou, Xu; Zheng, Baoying; Melrose, Heather L; Mosley, Thomas; Wang, Jun Ming

    2017-07-01

    LRRK2 G2019S mutation is associated with increased kinase activity and is the most common mutation associated with late-onset PD. However, the transgenic mouse model has not recapitulated cardinal PD-related motor phenotypes. Non-motor symptoms of PD including cognitive impairments are very common and may appear earlier than the motor symptoms. The objective of this study was to determine whether human LRRK2 with G2019S mutation causes hippocampus-dependent cognitive deficits in mice. Male (LRRK2-G2019S) LRRK2-Tg mice showed impairments in the early portion of the Two-day radial arm water maze acquisition trial as well as in the reversal learning on the third day. However, their performance was similar to Non-Tg controls in the probe trial. LRRK2-Tg mice also displayed impairments in the novel arm discrimination test but not in the spontaneous alternation test in Y-maze. Interestingly, there was no statistically significant locomotor impairment during any of these cognitive test, nor in the locomotor tests including open field, accelerating rotarod and pole tests. Expression of the postsynaptic protein PSD-95 but not the presynaptic protein synaptophysin was lower in hippocampal homogenates of LRRK2-Tg mice. Consistent with previous reports in human LRRK2 G2019S carriers, the current data suggests that cognitive dysfunctions are present in LRRK2-Tg mice even in the absence of locomotor impairment. LRRK2 G2019S mutation represses the postsynaptic protein PSD-95 but not the presynaptic protein synaptophysin. This study also suggests that mild cognitive impairment may appear earlier than motor dysfunctions in LRRK2-G2019S mutation carriers. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Stabilization of the angiotensin-(1-7) receptor Mas through interaction with PSD95.

    Science.gov (United States)

    Bian, Weihua; Sun, Licui; Yang, Longyan; Li, Ji-Feng; Hu, Jia; Zheng, Shuai; Guo, Ruihan; Feng, Duiping; Ma, Qian; Shi, Xiaocui; Xiong, Ying; Yang, Xiaomei; Song, Ran; Xu, Jianguo; Wang, Songlin; He, Junqi

    2013-08-01

    The functions and signalling mechanisms of the Ang-(1-7) [angiotensin-(1-7)] receptor Mas have been studied extensively. However, less attention has been paid to the intracellular regulation of Mas protein. In the present study, PSD95 (postsynaptic density 95), a novel binding protein of Mas receptor, was identified, and their association was characterized further. Mas specifically interacts with PDZ1-2, but not the PDZ3, domain of PSD95 via Mas-CT (Mas C-terminus), and the last four amino acids [ETVV (Glu-Thr-Val-Val)] of Mas-CT were determined to be essential for this interaction, as shown by GST pull-down, co-immunoprecipitation and confocal co-localization experiments. Gain-of-function and loss-of-function studies indicated that PSD95 enhanced Mas protein expression by increasing the stabilization of the receptor. Mas degradation was robustly inhibited by the proteasome inhibitor MG132 in time- and dose-dependent manners, and the expression of PSD95 impaired Mas ubiquitination, indicating that the PSD95-Mas association inhibits Mas receptor degradation via the ubiquitin-proteasome proteolytic pathway. These findings reveal a novel mechanism of Mas receptor regulation by which its expression is modulated at the post-translational level by ubiquitination, and clarify the role of PSD95, which binds directly to Mas, blocking the ubiquitination and subsequent degradation of the receptor via the ubiquitin-proteasome proteolytic pathway.

  8. Effects of Different Training Loads on Emotional State and mRNA and Protein Expressions of N-Methyl-D-Aspartate Receptor Subunits, Postsynaptic Density 95, and Kinesin Family Member 17 in Hippocampus of Rats

    Science.gov (United States)

    Ren, Hefei; Yu, Xinyi; Yu, Liren; Zhang, Yinguo; Xie, Hong; Shi, Na; Chen, Lijun

    2017-01-01

    Background Emotional state can be affected by different training loads. The aim of this study was to explore the changes of rat emotional state, as well as the mRNA and protein expressions of N-methyl-D-aspartate receptors (NMDARs), postsynaptic density 95 (PSD-95), and kinesin family member 17 (KIF-17) in the hippocampus, by long-term moderate-intensity and high-intensity training models in rats. Material/Methods The exercise model of SD rats was set up by treadmill running of moderate and high intensities for 4 weeks. The rats in the moderate-intensity training group were given endurance training with increasing intensity, while rats in the high-intensity training group were given high-speed training, and those in the normal control group were also established. The body weights of rats were measured before and after exercise to determine weight reduction. Real-time PCR and Western blotting were used to detect the mRNA and protein expressions of NMDARs, PSD-95, and KIF-17 in hippocampus of rats under different training loads. Results Compared with the control group, the rats in the moderate-intensity training group had better body condition and emotional state, while the rats in the high-intensity training group had poor body condition and emotional state. The mRNA and protein expression of PSD-95, KIF-17, and NMDARs in the moderate-intensity training group were significantly elevated (Ptraining group were suppressed (Ptraining loads have remarkable influences on the cognition, emotion, and mental status of rats, and can affect the mRNA and protein expressions of NMDARs, PSD-95, and KIF-17 in rats. Appropriate training loads alleviate hypoxia damage to the hippocampus, and also effectively improve hippocampus function. PMID:29038420

  9. Effect of complex aerobic physical exercise on PSD-95 in the hippocampus and on cognitive function in juvenile mice

    Science.gov (United States)

    Satriani, W. H.; Redjeki, S.; Kartinah, N. T.

    2017-08-01

    Increased neuroplasticity induced by complex aerobic physical exercise is associated with improved cognitive function in adult mice. Increased cognitive function is assumed to be based on increased synapse formation. One of the regions of the brain that is important in cognitive function is the hippocampus, which plays a role in memory formation. Post synaptic density-95 (PSD-95) is an adhesion protein of the post-synaptic density scaffolding that is essential to synaptic stabilization. As we age, the PSD-95 molecule matures the synapses needed for the formation of the basic circuitry of the nervous system in the brain. However, during the growth period, synapse elimination is higher than its formation. This study aims to determine whether complex aerobic exercise can improve cognitive function and PSD-95 levels in the hippocampus of juvenile mice during their growth stage. The mice performed complex aerobic exercise starting at five weeks of age and continuing for seven weeks with a gradual increase of 8 m/min. At eight weeks it was increased to 10 m/min. The exercise was done for five days of each week. The subjects of the study were tested for cognition one week before being sacrificed (at 12 weeks). The PSD-95 in the hippocampus was measured with ELISA. The results showed that there was a significant difference in cognitive function, where p exercise and a control group that did not. However, the PSD-95 levels did not differ significantly between the two groups. The results of this study indicate that early complex aerobic exercise can improve cognitive ability in adulthood but does not increase the levels of PSD-95 in adults.

  10. PSD-95 is post-transcriptionally repressed during early neural development by PTBP1 and PTBP2

    DEFF Research Database (Denmark)

    Zheng, Sika; Gray, Erin E; Chawla, Geetanjali

    2012-01-01

    Postsynaptic density protein 95 (PSD-95) is essential for synaptic maturation and plasticity. Although its synaptic regulation has been widely studied, the control of PSD-95 cellular expression is not understood. We found that Psd-95 was controlled post-transcriptionally during neural development...

  11. Beta1-adrenergic receptor-mediated dilation of rat cerebral artery requires Shaker-type KV1 channels on PSD95 scaffold.

    Science.gov (United States)

    Moore, Christopher L; McClenahan, Samantha J; Hanvey, Hillary M; Jang, Dae-Song; Nelson, Piper L; Joseph, Biny K; Rhee, Sung W

    2015-09-01

    Postsynaptic density-95 (PSD95) is a scaffolding protein in cerebral vascular smooth muscle cells (cVSMCs), which binds to Shaker-type K(+) (KV1) channels and facilitates channel opening through phosphorylation by protein kinase A. β1-Adrenergic receptors (β1ARs) also have a binding motif for PSD95. Functional association of β1AR with KV1 channels through PSD95 may represent a novel vasodilator complex in cerebral arteries (CA). We explored whether a β1AR-PSD95-KV1 complex is a determinant of rat CA dilation. RT-PCR and western blots revealed expression of β1AR in CA. Isoproterenol induced a concentration-dependent dilation of isolated, pressurized rat CA that was blocked by the β1AR blocker CGP20712. Cranial window imaging of middle cerebral arterioles in situ showed isoproterenol- and norepinephrine-induced dilation that was blunted by β1AR blockade. Isoproterenol-induced hyperpolarization of cVSMCs in pressurized CA was blocked by CGP20712. Confocal images of cVSMCs immunostained with antibodies against β1AR and PSD95 indicated strong colocalization, and PSD95 co-immunoprecipitated with β1AR in CA lysate. Blockade of KV1 channels, β1AR or disruption of PSD95-KV1 interaction produced similar blunting of isoproterenol-induced dilation in pressurized CA. These findings suggest that PSD95 mediates a vasodilator complex with β1AR and KV1 channels in cVSMCs. This complex may be critical for proper vasodilation in rat CA.

  12. Modified peptides as potent inhibitors of the postsynaptic density-95/N-methyl-D-aspartate receptor interaction

    DEFF Research Database (Denmark)

    Bach, Anders; Chi, Celestine N.; Olsen, Thomas B.

    2008-01-01

    and unnatural amino acids, which disclosed a tripeptide with micromolar affinity and N-methylated tetrapeptides with improved affinities. Molecular modeling studies guided further N-terminal modifications and introduction of a range of N-terminal substitutions dramatically improved affinity. The best compound......, N-cyclohexylethyl-ETAV (56), demonstrated up to 19-fold lower K i value ( K i = 0.94 and 0.45 microM against PDZ1 and PDZ2 of PSD-95, respectively) compared to wild-type values, providing the most potent inhibitors of this interaction reported so far. These novel and potent inhibitors provide...

  13. Live imaging of endogenous PSD-95 using ENABLED: a conditional strategy to fluorescently label endogenous proteins.

    Science.gov (United States)

    Fortin, Dale A; Tillo, Shane E; Yang, Guang; Rah, Jong-Cheol; Melander, Joshua B; Bai, Suxia; Soler-Cedeño, Omar; Qin, Maozhen; Zemelman, Boris V; Guo, Caiying; Mao, Tianyi; Zhong, Haining

    2014-12-10

    Stoichiometric labeling of endogenous synaptic proteins for high-contrast live-cell imaging in brain tissue remains challenging. Here, we describe a conditional mouse genetic strategy termed endogenous labeling via exon duplication (ENABLED), which can be used to fluorescently label endogenous proteins with near ideal properties in all neurons, a sparse subset of neurons, or specific neuronal subtypes. We used this method to label the postsynaptic density protein PSD-95 with mVenus without overexpression side effects. We demonstrated that mVenus-tagged PSD-95 is functionally equivalent to wild-type PSD-95 and that PSD-95 is present in nearly all dendritic spines in CA1 neurons. Within spines, while PSD-95 exhibited low mobility under basal conditions, its levels could be regulated by chronic changes in neuronal activity. Notably, labeled PSD-95 also allowed us to visualize and unambiguously examine otherwise-unidentifiable excitatory shaft synapses in aspiny neurons, such as parvalbumin-positive interneurons and dopaminergic neurons. Our results demonstrate that the ENABLED strategy provides a valuable new approach to study the dynamics of endogenous synaptic proteins in vivo. Copyright © 2014 the authors 0270-6474/14/3416698-15$15.00/0.

  14. Olfactory receptor signaling is regulated by the post-synaptic density 95, Drosophila discs large, zona-occludens 1 (PDZ) scaffold multi-PDZ domain protein 1.

    LENUS (Irish Health Repository)

    Dooley, Ruth

    2009-12-01

    The unique ability of mammals to detect and discriminate between thousands of different odorant molecules is governed by the diverse array of olfactory receptors expressed by olfactory sensory neurons in the nasal epithelium. Olfactory receptors consist of seven transmembrane domain G protein-coupled receptors and comprise the largest gene superfamily in the mammalian genome. We found that approximately 30% of olfactory receptors possess a classical post-synaptic density 95, Drosophila discs large, zona-occludens 1 (PDZ) domain binding motif in their C-termini. PDZ domains have been established as sites for protein-protein interaction and play a central role in organizing diverse cell signaling assemblies. In the present study, we show that multi-PDZ domain protein 1 (MUPP1) is expressed in the apical compartment of olfactory sensory neurons. Furthermore, on heterologous co-expression with olfactory sensory neurons, MUPP1 was shown to translocate to the plasma membrane. We found direct interaction of PDZ domains 1 + 2 of MUPP1 with the C-terminus of olfactory receptors in vitro. Moreover, the odorant-elicited calcium response of OR2AG1 showed a prolonged decay in MUPP1 small interfering RNA-treated cells. We have therefore elucidated the first building blocks of the putative \\'olfactosome\\

  15. Impairment of TrkB-PSD-95 signaling in Angelman syndrome.

    Directory of Open Access Journals (Sweden)

    Cong Cao

    Full Text Available Angelman syndrome (AS is a neurodevelopment disorder characterized by severe cognitive impairment and a high rate of autism. AS is caused by disrupted neuronal expression of the maternally inherited Ube3A ubiquitin protein ligase, required for the proteasomal degradation of proteins implicated in synaptic plasticity, such as the activity-regulated cytoskeletal-associated protein (Arc/Arg3.1. Mice deficient in maternal Ube3A express elevated levels of Arc in response to synaptic activity, which coincides with severely impaired long-term potentiation (LTP in the hippocampus and deficits in learning behaviors. In this study, we sought to test whether elevated levels of Arc interfere with brain-derived neurotrophic factor (BDNF TrkB receptor signaling, which is known to be essential for both the induction and maintenance of LTP. We report that TrkB signaling in the AS mouse is defective, and show that reduction of Arc expression to control levels rescues the signaling deficits. Moreover, the association of the postsynaptic density protein PSD-95 with TrkB is critical for intact BDNF signaling, and elevated levels of Arc were found to impede PSD-95/TrkB association. In Ube3A deficient mice, the BDNF-induced recruitment of PSD-95, as well as PLCγ and Grb2-associated binder 1 (Gab1 with TrkB receptors was attenuated, resulting in reduced activation of PLCγ-α-calcium/calmodulin-dependent protein kinase II (CaMKII and PI3K-Akt, but leaving the extracellular signal-regulated kinase (Erk pathway intact. A bridged cyclic peptide (CN2097, shown by nuclear magnetic resonance (NMR studies to uniquely bind the PDZ1 domain of PSD-95 with high affinity, decreased the interaction of Arc with PSD-95 to restore BDNF-induced TrkB/PSD-95 complex formation, signaling, and facilitate the induction of LTP in AS mice. We propose that the failure of TrkB receptor signaling at synapses in AS is directly linked to elevated levels of Arc associated with PSD-95 and PSD-95

  16. Reduced SNAP-25 increases PSD-95 mobility and impairs spine morphogenesis.

    Science.gov (United States)

    Fossati, G; Morini, R; Corradini, I; Antonucci, F; Trepte, P; Edry, E; Sharma, V; Papale, A; Pozzi, D; Defilippi, P; Meier, J C; Brambilla, R; Turco, E; Rosenblum, K; Wanker, E E; Ziv, N E; Menna, E; Matteoli, M

    2015-09-01

    Impairment of synaptic function can lead to neuropsychiatric disorders collectively referred to as synaptopathies. The SNARE protein SNAP-25 is implicated in several brain pathologies and, indeed, brain areas of psychiatric patients often display reduced SNAP-25 expression. It has been recently found that acute downregulation of SNAP-25 in brain slices impairs long-term potentiation; however, the processes through which this occurs are still poorly defined. We show that in vivo acute downregulation of SNAP-25 in CA1 hippocampal region affects spine number. Consistently, hippocampal neurons from SNAP-25 heterozygous mice show reduced densities of dendritic spines and defective PSD-95 dynamics. Finally, we show that, in brain, SNAP-25 is part of a molecular complex including PSD-95 and p140Cap, with p140Cap being capable to bind to both SNAP-25 and PSD-95. These data demonstrate an unexpected role of SNAP-25 in controlling PSD-95 clustering and open the possibility that genetic reductions of the protein levels - as occurring in schizophrenia - may contribute to the pathology through an effect on postsynaptic function and plasticity.

  17. UCCB01-125, a dimeric inhibitor of PSD-95, reduces inflammatory pain without disrupting cognitive or motor performance: Comparison with the NMDA receptor antagonist MK-801

    DEFF Research Database (Denmark)

    Andreasen, Jesper T.; Bach, Anders; Gynther, Mikko

    2013-01-01

    Excessive N-Methyl-d-aspartate receptor (NMDAR)-dependent production of nitric oxide (NO) is involved in the development and maintenance of chronic pain states, and is mediated by postsynaptic density protein-95 (PSD-95). By binding to both the NMDAR and neuronal NO synthase (nNOS), PSD-95 mediates...... the NMDAR/PSD-95/nNOS complex by targeting PSD-95, thereby decreasing NO production without interfering with the NMDAR ion channel function. Here, we compared the effects of a dimeric PSD-95 inhibitor, UCCB01-125, and the NMDAR antagonist, MK-801, on mechanical hypersensitivity in the complete Freund......-induced mechanical hypersensitivity 1 and 24 h after treatment. Moreover, UCCB01-125 was found to reverse CFA-induced hypersensitivity when administered 24 h after CFA treatment, an effect lasting for at least 3 days. At the dose reducing hypersensitivity, MK-801 disrupted attention, long-term memory, and motor...

  18. Effects of the dimeric PSD-95 inhibitor UCCB01-144 in mouse models of pain, cognition and motor function

    DEFF Research Database (Denmark)

    Andreasen, Jesper T; Nasser, Arafat; Caballero-Puntiverio, Maitane

    2016-01-01

    NMDAR antagonism shows analgesic action in humans and animal pain models, but disrupts cognitive and motor functions. NMDAR-dependent NO production requires tethering of the NMDAR to neuronal NO synthase (nNOS) by the postsynaptic density protein-95 (PSD-95). Perturbing the NMDAR/PSD-95/nNOS inte...... in the STFP test. Collectively, UCCB01-144 reversed both CFA and SNI-induced hypersensitivity, but the efficacy in the SNI model was only transient. This suggests that enhanced BBB permeability of PSD-95 inhibitors improves the analgesic action in neuropathic pain states.......NOS interaction has therefore been proposed as an alternative analgesic mechanism. We recently reported that UCCB01-125, a dimeric PSD-95 inhibitor with limited blood-brain-barrier permeability, reduced mechanical hypersensitivity in the complete Freund's adjuvant (CFA) inflammatory pain model, without disrupting...... of neuropathic pain. Potential cognitive effects of UCCB01-144 were examined using the social transmission of food preference (STFP) test and the V-maze test, and motor coordination was assessed with the rotarod test. UCCB01-144 (10mg/kg) reversed CFA-induced mechanical hypersensitivity after 1h, and completely...

  19. DA Negatively Regulates IGF-I Actions Implicated in Cognitive Function via Interaction of PSD95 and nNOS in Minimal Hepatic Encephalopathy

    Directory of Open Access Journals (Sweden)

    Saidan Ding

    2017-09-01

    Full Text Available Insulin-like growth factor I (IGF-I has been positively correlated with cognitive ability. Cognitive decline in minimal hepatic encephalopathy (MHE was shown to be induced by elevated intracranial dopamine (DA. The beneficial effect of IGF-I signaling in MHE remains unknown. In this study, we found that IGF-I content was reduced in MHE rats and that IGF-I administration mitigated cognitive decline of MHE rats. A protective effect of IGF-I on the DA-induced interaction between postsynaptic density protein 95 (PSD95 and neuronal nitric oxide synthase (nNOS was found in neurons. Ribosomal S6 protein kinase (RSK phosphorylated nNOS in response to IGF-I by recruiting extracellular signal-regulated kinase (ERK1/2. In turn, DA inactivated the ERK1/2/RSK pathway and stimulated the PSD95–nNOS interaction by downregulating IGF-I. Inhibition of the interaction between PSD95 and nNOS ameliorated DA-induced memory impairment. As DA induced deficits in the ERK1/2/RSK pathway and the interaction between PSD95 and nNOS in MHE brains, IGF-I administration exerted a protective effect via interruption of the interaction between PSD95 and nNOS. These results suggest that IGF-I antagonizes DA-induced cognitive loss by disrupting PSD95–nNOS interactions in MHE.

  20. A high-affinity, dimeric inhibitor of PSD-95 bivalently interacts with PDZ1-2 and protects against ischemic brain damage

    DEFF Research Database (Denmark)

    Bach, Anders*; Clausen, Bettina H; Møller, Magda

    2012-01-01

    Inhibition of the ternary protein complex of the synaptic scaffolding protein postsynaptic density protein-95 (PSD-95), neuronal nitric oxide synthase (nNOS), and the N-methyl-d-aspartate (NMDA) receptor is a potential strategy for treating ischemic brain damage, but high-affinity inhibitors...

  1. G quadruplex RNA structures in PSD-95 mRNA: potential regulators of miR-125a seed binding site accessibility.

    Science.gov (United States)

    Stefanovic, Snezana; Bassell, Gary J; Mihailescu, Mihaela Rita

    2015-01-01

    Fragile X syndrome (FXS) is the most common inherited form of intellectual disability caused by the CGG trinucleotide expansion in the 3'-untranslated region of the FMR1 gene on the X chromosome, that silences the expression of the Fragile X mental retardation protein (FMRP). FMRP has been shown to bind to a G-rich region within the PSD-95 mRNA which encodes for the postsynaptic density protein 95 (PSD-95), and together with the microRNA miR-125a, to play an important role in the reversible inhibition of the PSD-95 mRNA translation in neurons. The loss of FMRP in Fmr1 KO mice disables this translation control in the production of the PSD-95 protein. Interestingly, the miR-125a binding site on PSD-95 mRNA is embedded in the G-rich region bound by FMRP and postulated to adopt one or more G quadruplex structures. In this study, we have used different biophysical techniques to validate and characterize the formation of parallel G quadruplex structures and binding of miR-125a to its complementary sequence located within the 3' UTR of PSD-95 mRNA. Our results indicate that the PSD-95 mRNA G-rich region folds into alternate G quadruplex conformations that coexist in equilibrium. miR-125a forms a stable complex with PSD-95 mRNA, as evident by characteristic Watson-Crick base-pairing that coexists with one of the G quadruplex forms, suggesting a novel mechanism for G quadruplex structures to regulate the access of miR-125a to its binding site. © 2014 Stefanovic et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  2. Assessment of ZnT3 and PSD95 protein levels in Lewy body dementias and Alzheimer's disease: association with cognitive impairment.

    Science.gov (United States)

    Whitfield, David R; Vallortigara, Julie; Alghamdi, Amani; Howlett, David; Hortobágyi, Tibor; Johnson, Mary; Attems, Johannes; Newhouse, Stephen; Ballard, Clive; Thomas, Alan J; O'Brien, John T; Aarsland, Dag; Francis, Paul T

    2014-12-01

    The loss of zinc transporter 3 (ZnT3) has been implicated in age-related cognitive decline in mice, and the protein has been associated with plaques. We investigated the levels of ZnT3 and postsynaptic density protein 95 (PSD95), a marker of the postsynaptic terminal, in people with Parkinson's disease dementia (PDD, n = 31), dementia with Lewy bodies (DLB, n = 44), Alzheimer's disease (AD, n = 16), and controls (n = 24), using semiquantitative western blotting and immunohistochemistry in 3 cortical regions. Standardized cognitive assessments during life and semiquantitative scoring of amyloid β (Aβ), tau, and α-synuclein at postmortem were used to investigate the relationship between ZnT3 and PSD95, cognition and pathology. Associations were observed between ZnT3 and PSD95 levels in prefrontal cortex and cognitive impairment (p = 0.001 and p = 0.002, respectively) and between ZnT3 levels in the parietal cortex and cognitive impairment (p = 0.036). Associations were also seen between ZnT3 levels in cingulate cortex and severity of Aβ (p = 0.003) and tau (p = 0.011) pathologies. DLB and PDD were characterized by significant reductions of PSD95 (p < 0.05) and ZnT3 (p < 0.001) in prefrontal cortex compared with controls and AD. PSD95 levels in the parietal cortex were found to be decreased in AD cases compared with controls (p = 0.02) and PDD (p = 0.005). This study has identified Zn(2+) modulation as a possible novel target for the treatment of cognitive impairment in DLB and PDD and the potential for synaptic proteins to be used as a biomarker for the differentiation of DLB and PDD from AD. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. A Specific Nutrient Combination Attenuates the Reduced Expression of PSD-95 in the Proximal Dendrites of Hippocampal Cell Body Layers in a Mouse Model of Phenylketonuria

    Science.gov (United States)

    Bruinenberg, Vibeke M.; van Vliet, Danique; Attali, Amos; de Wilde, Martijn C.; Kuhn, Mirjam; van Spronsen, Francjan J.; van der Zee, Eddy A.

    2016-01-01

    The inherited metabolic disease phenylketonuria (PKU) is characterized by increased concentrations of phenylalanine in the blood and brain, and as a consequence neurotransmitter metabolism, white matter, and synapse functioning are affected. A specific nutrient combination (SNC) has been shown to improve synapse formation, morphology and function. This could become an interesting new nutritional approach for PKU. To assess whether treatment with SNC can affect synapses, we treated PKU mice with SNC or an isocaloric control diet and wild-type (WT) mice with an isocaloric control for 12 weeks, starting at postnatal day 31. Immunostaining for post-synaptic density protein 95 (PSD-95), a post-synaptic density marker, was carried out in the hippocampus, striatum and prefrontal cortex. Compared to WT mice on normal chow without SNC, PKU mice on the isocaloric control showed a significant reduction in PSD-95 expression in the hippocampus, specifically in the granular cell layer of the dentate gyrus, with a similar trend seen in the cornus ammonis 1 (CA1) and cornus ammonis 3 (CA3) pyramidal cell layer. No differences were found in the striatum or prefrontal cortex. PKU mice on a diet supplemented with SNC showed improved expression of PSD-95 in the hippocampus. This study gives the first indication that SNC supplementation has a positive effect on hippocampal synaptic deficits in PKU mice. PMID:27102170

  4. Design and synthesis of triazole-based peptidomimetics of a PSD-95 PDZ domain inhibitor

    DEFF Research Database (Denmark)

    Bach, Anders; Pedersen, Thomas B.; Strømgaard, Kristian

    2016-01-01

    PSD-95 PDZ domains are biologically important and promising drug targets. Here, we discover a triazole-based peptidomimetic, 10, by ‘click chemistry’. Compound 10 inhibits the PDZ2/GluN2B interaction with affinity similar to tripeptide SAV and better than current small-molecules. Thus, 10...

  5. Rigidified Clicked Dimeric Ligands for Studying the Dynamics of the PDZ1-2 Supramodule of PSD-95

    DEFF Research Database (Denmark)

    Eildal, Jonas N N; Bach, Anders; Dogan, Jakob

    2015-01-01

    PSD-95 is a scaffolding protein of the MAGUK protein family, and engages in several vital protein-protein interactions in the brain with its PDZ domains. It has been suggested that PSD-95 is composed of two supramodules, one of which is the PDZ1-2 tandem domain. Here we have developed rigidified...

  6. Employment of Molecularly Imprinted Polymers to High-Throughput Screen nNOS-PSD-95 Interruptions: Structure and Dynamics Investigations on Monomer-Template Complexation.

    Science.gov (United States)

    Wang, Yongwei; Zhao, Ting; Dai, Peng; Jiang, Nan; Li, Fei

    2016-03-16

    Molecularly imprinted polymers (MIPs) are employed to screen nNOS-PSD-95 (neuronal nitric oxide synthase post-synaptic density protein-95) interruptions. 5-(3,5-Dichloro-2-hydroxybenzylamino)-2-hydroxybenzoic acid (ZL006; a potential drug candidate for the treatment of stroke, depression, and pain) is employed as a template. Four kinds of functional monomers (2-VP: 2-vinylpyridine; 4-VP: 4-vinylpyridine; MMA: methyl methacrylate; and MAAM: methacrylamide) are designed, and their complexation with ZL006 in various solvents (methanol, acetonitrile, toluene, chloroform) is investigated by molecular dynamics simulations and quantum mechanics calculations. Both 4-VP and MAAM have stronger interactions with ZL006 than those of 2-VP and MMA. The appropriate ratio of monomer to template is 3:1. Intermolecular hydrogen bonds play a dominant role in monomer-template complexation. Ideal solvents are toluene and chloroform, and the solvation effect on monomer-template complexation is revealed. Both molecular modeling and adsorption experiments demonstrate that as-synthesized ZL006-MIP with 4-VP as a monomer has better selectivity than that employing MAAM to screen for nNOS-PSD-95 interruptions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Ligand binding to the PDZ domains of postsynaptic density protein 95

    DEFF Research Database (Denmark)

    Toto, Angelo; Pedersen, Søren W; Karlsson, O Andreas

    2016-01-01

    Cellular scaffolding and signalling is generally governed by multidomain proteins, where each domain has a particular function. Postsynaptic density protein 95 (PSD-95) is involved in synapse formation and is a typical example of such a multidomain protein. Protein-protein interactions of PSD-95 ...

  8. Tolerance to ethanol intoxication after chronic ethanol: role of GluN2A and PSD-95.

    Science.gov (United States)

    Daut, Rachel A; Busch, Erica F; Ihne, Jessica; Fisher, Daniel; Mishina, Masayoshi; Grant, Seth G N; Camp, Marguerite; Holmes, Andrew

    2015-03-01

    The neural and genetic factors underlying chronic tolerance to alcohol are currently unclear. The GluN2A N-methyl-D-aspartate receptors (NMDAR) subunit and the NMDAR-anchoring protein PSD-95 mediate acute alcohol intoxication and represent putative mechanisms mediating tolerance. We found that chronic intermittent ethanol exposure (CIE) did not produce tolerance [loss of righting reflex (LORR)] or withdrawal-anxiety in C57BL/6J, GluN2A or PSD-95 knockout mice assayed 2-3 days later. However, significant tolerance to LORR was evident 1 day after CIE in C57BL/6J and PSD-95 knockouts, but absent in GluN2A knockouts. These data suggest a role for GluN2A in tolerance, extending evidence that human GluN2A gene variation is involved in alcohol dependence. © 2014 Society for the Study of Addiction.

  9. PSD-95 uncoupling from NMDA receptors by Tat-N-dimer ameliorates neuronal depolarisation in cortical spreading depression

    DEFF Research Database (Denmark)

    Kucharz, Krzysztof; Søndergaard Rasmussen, Ida; Bach, Anders

    2017-01-01

    , UCCB01-144 (Tat-N-dimer) ameliorates the persistent effects of cortical spreading depression on cortical function. Using in vivo two-photon microscopy in somatosensory cortex in mice, we show that fluorescently labelled Tat-N-dimer readily crosses blood-brain barrier and accumulates in nerve cells...... depression on cortical blood flow and CMRO2 We suggest that uncoupling of PSD-95 from NMDA receptors reduces overall neuronal excitability and the amplitude of the spreading depolarisation wave. These findings may be of interest for understanding the neuroprotective effects of the nNOS/PSD-95 uncoupling...

  10. Single-Molecule Imaging of PSD-95 mRNA Translation in Dendrites and Its Dysregulation in a Mouse Model of Fragile X Syndrome.

    Science.gov (United States)

    Ifrim, Marius F; Williams, Kathryn R; Bassell, Gary J

    2015-05-06

    Fragile X syndrome (FXS) is caused by the loss of the fragile X mental retardation protein (FMRP), an RNA binding protein that regulates translation of numerous target mRNAs, some of which are dendritically localized. Our previous biochemical studies using synaptoneurosomes demonstrate a role for FMRP and miR-125a in regulating the translation of PSD-95 mRNA. However, the local translation of PSD-95 mRNA within dendrites and spines, as well as the roles of FMRP or miR-125a, have not been directly studied. Herein, local synthesis of a Venus-PSD-95 fusion protein was directly visualized in dendrites and spines using single-molecule imaging of a diffusion-restricted Venus-PSD-95 reporter under control of the PSD-95 3'UTR. The basal translation rates of Venus-PSD-95 mRNA was increased in cultured hippocampal neurons from Fmr1 KO mice compared with WT neurons, which correlated with a transient elevation of endogenous PSD-95 within dendrites. Following mGluR stimulation with (S)-3,5-dihydroxyphenylglycine, the rate of Venus-PSD-95 mRNA translation increased rapidly in dendrites of WT hippocampal neurons, but not in those of Fmr1 KO neurons or when the binding site of miR125a, previously shown to bind PSD-95 3'UTR, was mutated. This study provides direct support for the hypothesis that local translation within dendrites and spines is dysregulated in FXS. Impairments in the regulated local synthesis of PSD-95, a critical regulator of synaptic structure and function, may affect the spatiotemporal control of PSD-95 levels and affect dendritic spine development and synaptic plasticity in FXS. Copyright © 2015 the authors 0270-6474/15/357116-15$15.00/0.

  11. Effects of dimeric PSD-95 inhibition on excitotoxic cell death and outcome after controlled cortical impact in rats

    DEFF Research Database (Denmark)

    Sommer, Jens Bak; Bach, Anders; Rytter, Hana Malá

    2017-01-01

    be an effective therapeutic strategy in TBI. The objectives of the present study were to assess the effects of a dimeric inhibitor of PSD-95, UCCB01-144, on excitotoxic cell death in vitro and outcome after experimental TBI in rats in vivo. In addition, the pharmacokinetic parameters of UCCB01-144 were...... assessed in a water maze at two weeks post-trauma, and at four weeks lesion volumes were estimated. Overall, UCCB01-144 did not protect against NMDA-toxicity in neuronal cultures or experimental TBI in rats. Important factors that should be investigated further in future studies assessing the effects...

  12. Biochemical investigations of the mechanism of action of small molecules ZL006 and IC87201 as potential inhibitors of the nNOS-PDZ/PSD-95-PDZ interactions

    DEFF Research Database (Denmark)

    Bach, Anders

    2015-01-01

    ZL006 and IC87201 have been presented as efficient inhibitors of the nNOS/PSD-95 protein-protein interaction and shown great promise in cellular experiments and animal models of ischemic stroke and pain. Here, we investigate the proposed mechanism of action of ZL006 and IC87201 using biochemical...... and biophysical methods, such as fluorescence polarization (FP), isothermal titration calorimetry (ITC), and (1)H-(15)N HSQC NMR. Our data show that under the applied in vitro conditions, ZL006 and IC87201 do not interact with the PDZ domains of nNOS or PSD-95, nor inhibit the nNOS-PDZ/PSD-95-PDZ interface...... by interacting with the β-finger of nNOS-PDZ. Our findings have implications for further medicinal chemistry efforts of ZL006, IC87201 and analogues, and challenge the general and widespread view on their mechanism of action....

  13. PSD95 suppresses dendritic arbor development in mature hippocampal neurons by occluding the clustering of NR2B-NMDA receptors.

    Directory of Open Access Journals (Sweden)

    Fernando J Bustos

    Full Text Available Considerable evidence indicates that the NMDA receptor (NMDAR subunits NR2A and NR2B are critical mediators of synaptic plasticity and dendritogenesis; however, how they differentially regulate these processes is unclear. Here we investigate the roles of the NR2A and NR2B subunits, and of their scaffolding proteins PSD-95 and SAP102, in remodeling the dendritic architecture of developing hippocampal neurons (2-25 DIV. Analysis of the dendritic architecture and the temporal and spatial expression patterns of the NMDARs and anchoring proteins in immature cultures revealed a strong positive correlation between synaptic expression of the NR2B subunit and dendritogenesis. With maturation, the pruning of dendritic branches was paralleled by a strong reduction in overall and synaptic expression of NR2B, and a significant elevation in synaptic expression of NR2A and PSD95. Using constructs that alter the synaptic composition, we found that either over-expression of NR2B or knock-down of PSD95 by shRNA-PSD95 augmented dendritogenesis in immature neurons. Reactivation of dendritogenesis could also be achieved in mature cultured neurons, but required both manipulations simultaneously, and was accompanied by increased dendritic clustering of NR2B. Our results indicate that the developmental increase in synaptic expression of PSD95 obstructs the synaptic clustering of NR2B-NMDARs, and thereby restricts reactivation of dendritic branching. Experiments with shRNA-PSD95 and chimeric NR2A/NR2B constructs further revealed that C-terminus of the NR2B subunit (tail was sufficient to induce robust dendritic branching in mature hippocampal neurons, and suggest that the NR2B tail is important in recruiting calcium-dependent signaling proteins and scaffolding proteins necessary for dendritogenesis.

  14. The human PDZome: a gateway to PSD95-Disc large-zonula occludens (PDZ)-mediated functions.

    Science.gov (United States)

    Belotti, Edwige; Polanowska, Jolanta; Daulat, Avais M; Audebert, Stéphane; Thomé, Virginie; Lissitzky, Jean-Claude; Lembo, Frédérique; Blibek, Karim; Omi, Shizue; Lenfant, Nicolas; Gangar, Akanksha; Montcouquiol, Mireille; Santoni, Marie-Josée; Sebbagh, Michael; Aurrand-Lions, Michel; Angers, Stéphane; Kodjabachian, Laurent; Reboul, Jérome; Borg, Jean-Paul

    2013-09-01

    Protein-protein interactions organize the localization, clustering, signal transduction, and degradation of cellular proteins and are therefore implicated in numerous biological functions. These interactions are mediated by specialized domains able to bind to modified or unmodified peptides present in binding partners. Among the most broadly distributed protein interaction domains, PSD95-disc large-zonula occludens (PDZ) domains are usually able to bind carboxy-terminal sequences of their partners. In an effort to accelerate the discovery of PDZ domain interactions, we have constructed an array displaying 96% of the human PDZ domains that is amenable to rapid two-hybrid screens in yeast. We have demonstrated that this array can efficiently identify interactions using carboxy-terminal sequences of PDZ domain binders such as the E6 oncoviral protein and protein kinases (PDGFRβ, BRSK2, PCTK1, ACVR2B, and HER4); this has been validated via mass spectrometry analysis. Taking advantage of this array, we show that PDZ domains of Scrib and SNX27 bind to the carboxy-terminal region of the planar cell polarity receptor Vangl2. We also have demonstrated the requirement of Scrib for the promigratory function of Vangl2 and described the morphogenetic function of SNX27 in the early Xenopus embryo. The resource presented here is thus adapted for the screen of PDZ interactors and, furthermore, should facilitate the understanding of PDZ-mediated functions.

  15. Postsynaptic density protein 95 in the striosome and matrix compartments of the human neostriatum.

    Directory of Open Access Journals (Sweden)

    Ryoma eMorigaki

    2015-11-01

    Full Text Available The human neostriatum consists of two functional subdivisions referred to as the striosome (patch and matrix compartments. The striosome-matrix dopamine systems play a central role in cortico-thalamo-basal ganglia circuits, and their involvement is thought to underlie the genesis of multiple movement and behavioral disorders, and of drug addiction. Human neuropathology also has shown that striosomes and matrix have differential vulnerability patterns in several striatal neurodegenerative diseases. Postsynaptic density protein 95 (PSD-95, also known as DLG4, is a major scaffolding protein in the postsynaptic densities of dendritic spines. PSD-95 is now known to negatively regulate not only N-methyl-D-aspartate glutamate signaling, but also dopamine D1 signals at sites of postsynaptic transmission. Accordingly, a neuroprotective role for PSD-95 against dopamine D1 receptor (D1R-mediated neurotoxicity in striatal neurodegeneration also has been suggested. Here, we used a highly sensitive immunohistochemistry technique to show that in the human neostriatum, PSD-95 is differentially concentrated in the striosome and matrix compartments, with a higher density of PSD-95 labeling in the matrix compartment than in the striosomes. This compartment-specific distribution of PSD-95 was strikingly complementary to that of D1R. In addition to the possible involvement of PSD-95-mediated synaptic function in compartment-specific dopamine signals, we suggest that the striosomes might be more susceptible to D1R-mediated neurotoxicity than the matrix compartment. This notion may provide new insight into the compartment-specific vulnerability of MSNs in striatal neurodegeneration.

  16. FRET-FLIM investigation of PSD95-NMDA receptor interaction in dendritic spines; control by calpain, CaMKII and Src family kinase.

    Directory of Open Access Journals (Sweden)

    Kim Doré

    Full Text Available Little is known about the changes in protein interactions inside synapses during synaptic remodeling, as their live monitoring in spines has been limited. We used a FRET-FLIM approach in developing cultured rat hippocampal neurons expressing fluorescently tagged NMDA receptor (NMDAR and PSD95, two essential proteins in synaptic plasticity, to examine the regulation of their interaction. NMDAR stimulation caused a transient decrease in FRET between the NMDAR and PSD95 in spines of young and mature neurons. The activity of both CaMKII and calpain were essential for this effect in both developmental stages. Meanwhile, inhibition of Src family kinase (SFK had opposing impacts on this decrease in FRET in young versus mature neurons. Our data suggest concerted roles for CaMKII, SFK and calpain activity in regulating activity-dependent separation of PSD95 from GluN2A or GluN2B. Finally, we found that calpain inhibition reduced spine growth that was caused by NMDAR activity, supporting the hypothesis that PSD95-NMDAR separation is implicated in synaptic remodeling.

  17. In vitro and in vivo effects of a novel dimeric inhibitor of PSD-95 on excitotoxicity and functional recovery after experimental traumatic brain injury

    DEFF Research Database (Denmark)

    Sommer, Jens Bak; Bach, Anders; Rytter, Hana Malá

    2017-01-01

    PSD-95 inhibitors have been shown to be neuroprotective in stroke, but have only to a very limited extent been evaluated in the treatment of traumatic brain injury (TBI) that has pathophysiological mechanisms in common with stroke. The aims of the current study were to assess the effects of a nov...... studies taking important experimental factors such as timing of treatment, dosage, and anesthesia into consideration....

  18. [Effects of electroacupuncture at different acupoints on learning and memory ability and PSD-95 protein expression on hippocampus CA1 in rats with autism].

    Science.gov (United States)

    Zhang, Xue-Jun; Wu, Qiang

    2013-07-01

    To explore the effect mechanism of electroacupuncture (EA) at Changqiang (GV 1) or Baihui (GV 20) on autism based on molecular biology. The autism model was established by intraperitoneal injection of sodium valproate (VPA) in Wistar pregnant rats. Forty young rats with autism were selected and randomly divided into a model group, a non-acupoint group, an electroacupuncture at "Changqiang" (GV 1) (EAGV 1 for short) group and an electroacupuncture at "Baihui" (GV 20) (EAGV 20 for short) group. Another 10 normal young rats were selected as a blank group. In the EAGV 1 group, acupuncture was applied at Houhai [as Changqiang (GV 1)], then EA apparatus was connected with continuous wave, 2 Hz, 20 min, once a day for consecutive 20 days. The same EA manipulation as EAGV 1 group was used in the EAGV 20 group where "Baihui" (GV 20) was selected and non-acupoint group where non-acupoint in the right rib was selected. Blank group and model group were reared under the same conditions without any intervention. The escape latency and the ratio of swimming distance in platform quadrant to total swimming distance in each group were observed by using Morris water maze, and the PSD-95 protein expression in hippocampal CA 1 was measured by immunohistochemical techniques. Compared with the blank group, the escape latency in the model group and the non-acupoint group lengthened (both P swimming distance in platform quadrant to total swimming distance was decreased (both P swimming distance in platform quadrant to total swimming distance was increased, the PSD-95 protein expression was increased (both P swimming distance in platform quadrant to total swimming distance and the PSD-95 protein expression had no significant difference between EAGV 1 group and EAGV 20 group (P > 0.05). Electroacupuncture at Changqiang (GV 1) or Baihui (GV 20) can respectively improve learning and memory ability of rats with autism, which has no significant difference and the mechanism of action may be

  19. AAV-mediated overexpression of neuroserpin in the hippocampus decreases PSD-95 expression but does not affect hippocampal-dependent learning and memory.

    Science.gov (United States)

    Tsang, Vicky W K; Young, Deborah; During, Matthew J; Birch, Nigel P

    2014-01-01

    Neuroserpin is a serine protease inhibitor, or serpin, that is expressed in the nervous system and inhibits the protease tissue plasminogen activator (tPA). Neuroserpin has been suggested to play a role in learning and memory but direct evidence for such a role is lacking. Here we have used an adeno-associated virus (AAV) vector expression system to investigate the effect of neuroserpin on hippocampal-dependent learning and memory in the young adult rat. A FLAG-tagged neuroserpin construct was initially characterized by in vitro transcription/translation and transfection into HEK293 cells and shown to interact with tPA and be targeted to the secretory pathway. Targeted injection of a chimeric AAV1/2 vector expressing FLAG-neuroserpin resulted in localized overexpression in the dorsal hippocampus. Neuroserpin overexpression led to the appearance of an unstable neuroserpin:tPA complex in zymographic assays consistent with interaction with endogenous tPA in vivo. Rats overexpressing neuroserpin also showed a significant decrease in the levels of postsynaptic density protein 95, a major postsynaptic scaffolding protein. Three weeks after injection, a range of behavioural tests was performed to measure spatial and associative learning and memory, as well as innate and acquired fear. These tests provided no evidence of a role for neuroserpin in hippocampal-dependent learning and memory. In summary this study does not support a role for neuroserpin in hippocampal-dependent learning and memory in young adult rats but does suggest an involvement of neuroserpin in hippocampal synaptic plasticity.

  20. AAV-Mediated Overexpression of Neuroserpin in the Hippocampus Decreases PSD-95 Expression but Does Not Affect Hippocampal-Dependent Learning and Memory

    Science.gov (United States)

    Tsang, Vicky W. K.; Young, Deborah; During, Matthew J.; Birch, Nigel P.

    2014-01-01

    Neuroserpin is a serine protease inhibitor, or serpin, that is expressed in the nervous system and inhibits the protease tissue plasminogen activator (tPA). Neuroserpin has been suggested to play a role in learning and memory but direct evidence for such a role is lacking. Here we have used an adeno-associated virus (AAV) vector expression system to investigate the effect of neuroserpin on hippocampal-dependent learning and memory in the young adult rat. A FLAG-tagged neuroserpin construct was initially characterized by in vitro transcription/translation and transfection into HEK293 cells and shown to interact with tPA and be targeted to the secretory pathway. Targeted injection of a chimeric AAV1/2 vector expressing FLAG-neuroserpin resulted in localized overexpression in the dorsal hippocampus. Neuroserpin overexpression led to the appearance of an unstable neuroserpin:tPA complex in zymographic assays consistent with interaction with endogenous tPA in vivo. Rats overexpressing neuroserpin also showed a significant decrease in the levels of postsynaptic density protein 95, a major postsynaptic scaffolding protein. Three weeks after injection, a range of behavioural tests was performed to measure spatial and associative learning and memory, as well as innate and acquired fear. These tests provided no evidence of a role for neuroserpin in hippocampal-dependent learning and memory. In summary this study does not support a role for neuroserpin in hippocampal-dependent learning and memory in young adult rats but does suggest an involvement of neuroserpin in hippocampal synaptic plasticity. PMID:24608243

  1. AAV-mediated overexpression of neuroserpin in the hippocampus decreases PSD-95 expression but does not affect hippocampal-dependent learning and memory.

    Directory of Open Access Journals (Sweden)

    Vicky W K Tsang

    Full Text Available Neuroserpin is a serine protease inhibitor, or serpin, that is expressed in the nervous system and inhibits the protease tissue plasminogen activator (tPA. Neuroserpin has been suggested to play a role in learning and memory but direct evidence for such a role is lacking. Here we have used an adeno-associated virus (AAV vector expression system to investigate the effect of neuroserpin on hippocampal-dependent learning and memory in the young adult rat. A FLAG-tagged neuroserpin construct was initially characterized by in vitro transcription/translation and transfection into HEK293 cells and shown to interact with tPA and be targeted to the secretory pathway. Targeted injection of a chimeric AAV1/2 vector expressing FLAG-neuroserpin resulted in localized overexpression in the dorsal hippocampus. Neuroserpin overexpression led to the appearance of an unstable neuroserpin:tPA complex in zymographic assays consistent with interaction with endogenous tPA in vivo. Rats overexpressing neuroserpin also showed a significant decrease in the levels of postsynaptic density protein 95, a major postsynaptic scaffolding protein. Three weeks after injection, a range of behavioural tests was performed to measure spatial and associative learning and memory, as well as innate and acquired fear. These tests provided no evidence of a role for neuroserpin in hippocampal-dependent learning and memory. In summary this study does not support a role for neuroserpin in hippocampal-dependent learning and memory in young adult rats but does suggest an involvement of neuroserpin in hippocampal synaptic plasticity.

  2. PDZ domain-mediated interactions of G protein-coupled receptors with postsynaptic density protein 95

    DEFF Research Database (Denmark)

    Møller, Thor C; Wirth, Volker F; Roberts, Nina Ingerslev

    2013-01-01

    G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins in the human genome. Their signaling is regulated by scaffold proteins containing PDZ domains, but although these interactions are important for GPCR function, they are still poorly understood. We here present...... a quantitative characterization of the kinetics and affinity of interactions between GPCRs and one of the best characterized PDZ scaffold proteins, postsynaptic density protein 95 (PSD-95), using fluorescence polarization (FP) and surface plasmon resonance (SPR). By comparing these in vitro findings....... The approach can easily be transferred to other receptors and scaffold proteins and this could help accelerate the discovery and quantitative characterization of GPCR-PDZ interactions....

  3. Exogenous Alpha-Synuclein Alters Pre- and Post-Synaptic Activity by Fragmenting Lipid Rafts

    Directory of Open Access Journals (Sweden)

    Marco Emanuele

    2016-05-01

    Full Text Available Alpha-synuclein (αSyn interferes with multiple steps of synaptic activity at pre-and post-synaptic terminals, however the mechanism/s by which αSyn alters neurotransmitter release and synaptic potentiation is unclear. By atomic force microscopy we show that human αSyn, when incubated with reconstituted membrane bilayer, induces lipid rafts' fragmentation. As a consequence, ion channels and receptors are displaced from lipid rafts with consequent changes in their activity. The enhanced calcium entry leads to acute mobilization of synaptic vesicles, and exhaustion of neurotransmission at later stages. At the post-synaptic terminal, an acute increase in glutamatergic transmission, with increased density of PSD-95 puncta, is followed by disruption of the interaction between N-methyl-d-aspartate receptor (NMDAR and PSD-95 with ensuing decrease of long term potentiation. While cholesterol loading prevents the acute effect of αSyn at the presynapse; inhibition of casein kinase 2, which appears activated by reduction of cholesterol, restores the correct localization and clustering of NMDARs.

  4. Remodeling of the postsynaptic plasma membrane during neural development.

    Science.gov (United States)

    Tulodziecka, Karolina; Diaz-Rohrer, Barbara B; Farley, Madeline M; Chan, Robin B; Di Paolo, Gilbert; Levental, Kandice R; Waxham, M Neal; Levental, Ilya

    2016-11-07

    Neuronal synapses are the fundamental units of neural signal transduction and must maintain exquisite signal fidelity while also accommodating the plasticity that underlies learning and development. To achieve these goals, the molecular composition and spatial organization of synaptic terminals must be tightly regulated; however, little is known about the regulation of lipid composition and organization in synaptic membranes. Here we quantify the comprehensive lipidome of rat synaptic membranes during postnatal development and observe dramatic developmental lipidomic remodeling during the first 60 postnatal days, including progressive accumulation of cholesterol, plasmalogens, and sphingolipids. Further analysis of membranes associated with isolated postsynaptic densities (PSDs) suggests the PSD-associated postsynaptic plasma membrane (PSD-PM) as one specific location of synaptic remodeling. We analyze the biophysical consequences of developmental remodeling in reconstituted synaptic membranes and observe remarkably stable microdomains, with the stability of domains increasing with developmental age. We rationalize the developmental accumulation of microdomain-forming lipids in synapses by proposing a mechanism by which palmitoylation of the immobilized scaffold protein PSD-95 nucleates domains at the postsynaptic plasma membrane. These results reveal developmental changes in lipid composition and palmitoylation that facilitate the formation of postsynaptic membrane microdomains, which may serve key roles in the function of the neuronal synapse. © 2016 Tulodziecka et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  5. Postsynaptic Signaling and Plasticity Mechanisms

    Science.gov (United States)

    Sheng, Morgan; Jong Kim, Myung

    2002-10-01

    In excitatory synapses of the brain, specific receptors in the postsynaptic membrane lie ready to respond to the release of the neurotransmitter glutamate from the presynaptic terminal. Upon stimulation, these glutamate receptors activate multiple biochemical pathways that transduce signals into the postsynaptic neuron. Different kinds of synaptic activity elicit different patterns of postsynaptic signals that lead to short- or long-lasting strengthening or weakening of synaptic transmission. The complex molecular mechanisms that underlie postsynaptic signaling and plasticity are beginning to emerge.

  6. Deciphering the kinetic binding mechanism of dimeric ligands using a potent plasma-stable dimeric inhibitor of postsynaptic density protein-95 as an example

    DEFF Research Database (Denmark)

    Chi, Celestine N; Bach, Anders; Gottschalk, Marie

    2010-01-01

    addressed the kinetic mechanism of interaction of such bivalent ligands. We have investigated the binding interaction of a recently identified potent plasma-stable dimeric pentapeptide and PDZ1-2 of postsynaptic density protein-95 (PSD-95) using protein engineering in combination with fluorescence...... constants involved in the binding reaction and found evidence for a conformational transition of the complex. Our data demonstrate the importance of a slow dissociation for a successful dimeric ligand but also highlight the possibility of optimizing the intramolecular association rate. The results may...

  7. Glutamatergic postsynaptic density protein dysfunctions in synaptic plasticity and dendritic spines morphology: relevance to schizophrenia and other behavioral disorders pathophysiology, and implications for novel therapeutic approaches.

    Science.gov (United States)

    de Bartolomeis, Andrea; Latte, Gianmarco; Tomasetti, Carmine; Iasevoli, Felice

    2014-02-01

    Emerging researches point to a relevant role of postsynaptic density (PSD) proteins, such as PSD-95, Homer, Shank, and DISC-1, in the pathophysiology of schizophrenia and autism spectrum disorders. The PSD is a thickness, detectable at electronic microscopy, localized at the postsynaptic membrane of glutamatergic synapses, and made by scaffolding proteins, receptors, and effector proteins; it is considered a structural and functional crossroad where multiple neurotransmitter systems converge, including the dopaminergic, serotonergic, and glutamatergic ones, which are all implicated in the pathophysiology of psychosis. Decreased PSD-95 protein levels have been reported in postmortem brains of schizophrenia patients. Variants of Homer1, a key PSD protein for glutamate signaling, have been associated with schizophrenia symptoms severity and therapeutic response. Mutations in Shank gene have been recognized in autism spectrum disorder patients, as well as reported to be associated to behaviors reminiscent of schizophrenia symptoms when expressed in genetically engineered mice. Here, we provide a critical appraisal of PSD proteins role in the pathophysiology of schizophrenia and autism spectrum disorders. Then, we discuss how antipsychotics may affect PSD proteins in brain regions relevant to psychosis pathophysiology, possibly by controlling synaptic plasticity and dendritic spine rearrangements through the modulation of glutamate-related targets. We finally provide a framework that may explain how PSD proteins might be useful candidates to develop new therapeutic approaches for schizophrenia and related disorders in which there is a need for new biological treatments, especially against some symptom domains, such as negative symptoms, that are poorly affected by current antipsychotics.

  8. Postsynaptic Receptors for Amyloid-β Oligomers as Mediators of Neuronal Damage in Alzheimer’s Disease

    Science.gov (United States)

    Dinamarca, Margarita C.; Ríos, Juvenal A.; Inestrosa, Nibaldo C.

    2012-01-01

    The neurotoxic effect of amyloid-β peptide (Aβ) over the central synapses has been described and is reflected in the decrease of some postsynaptic excitatory proteins, the alteration in the number and morphology of the dendritic spines, and a decrease in long-term potentiation. Many studies has been carried out to identify the putative Aβ receptors in neurons, and is still no clear why the Aβ oligomers only affect the excitatory synapses. Aβ oligomers bind to neurite and preferentially to the postsynaptic region, where the postsynaptic protein-95 (PSD-95) is present in the glutamatergic synapse, and interacts directly with the N-methyl-D-aspartate receptor (NMDAR) and neuroligin (NL). NL is a postsynaptic protein which binds to the presynaptic protein, neurexin to form a heterophilic adhesion complex, the disruption of this interaction affects the integrity of the synaptic contact. Structurally, NL has an extracellular domain homolog to acetylcholinesterase, the first synaptic protein that was found to interact with Aβ. In the present review we will document the interaction between Aβ and the extracellular domain of NL-1 at the excitatory synapse, as well as the interaction with other postsynaptic components, including the glutamatergic receptors (NMDA and mGluR5), the prion protein, the neurotrophin receptor, and the α7-nicotinic acetylcholine receptor. We conclude that several Aβ oligomers receptors exist at the excitatory synapse, which could be the responsible for the neurotoxic effect described for the Aβ oligomers. The characterization of the interaction between Aβ receptors and Aβ oligomers could help to understand the source of the neurologic damage observed in the brain of the Alzheimer’s disease patients. PMID:23267328

  9. D-aspartate dysregulation in Ddo(-/-) mice modulates phencyclidine-induced gene expression changes of postsynaptic density molecules in cortex and striatum.

    Science.gov (United States)

    de Bartolomeis, Andrea; Errico, Francesco; Aceto, Giuseppe; Tomasetti, Carmine; Usiello, Alessandro; Iasevoli, Felice

    2015-10-01

    N-methyl-D-aspartate receptor (NMDAR) hypofunction has been considered a key alteration in schizophrenia pathophysiology. Thus, several strategies aimed at enhancing glutamatergic transmission, included the introduction in therapy of D-amino acids, such as D-serine and D-cycloserine augmentation, have been proposed to counteract difficult-to-treat symptoms or treatment-resistant forms of schizophrenia. Another D-amino acid, D-aspartate, has recently gained increasing interest for its role in NMDAR activation and has been found reduced in post-mortem cortex of schizophrenia patients. NMDAR is the core of the postsynaptic density (PSD), a postsynaptic site involved in glutamate signaling and responsive to antipsychotic treatment. In this study, we investigated striatal and cortical gene expression of key PSD transcripts (i.e. Homer1a, Homer1b/c, and PSD-95) in mice with persistently elevated brain D-aspartate-levels, i.e. the D-aspartate-oxidase knockout mice (Ddo(-/-)). These animal models were analyzed both in naive condition and after phencyclidine (PCP) treatment. Naive Ddo(-/-) mice showed decreased Homer1a expression in the prefrontal cortex, increased Homer1b/c expression in the striatum, and decreased PSD-95 expression in the striatum and in the cortex. Acute PCP treatment restored, and even potentiated, Homer1a expression in the prefrontal cortex of mutant mice, while it had limited effects on the other genes. These results suggest that persistently elevated D-aspartate, by enhancing NMDA transmission, may cause complex adaptive mechanisms affecting Homer1a, which in turn may explain the recently demonstrated protective effects of this D-amino acid against PCP-induced behavioral alterations, such as ataxic behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Interaction of LDL receptor-related protein 4 (LRP4) with postsynaptic scaffold proteins via its C-terminal PDZ domain-binding motif, and its regulation by Ca/calmodulin-dependent protein kinase II.

    Science.gov (United States)

    Tian, Qing-Bao; Suzuki, Tatsuo; Yamauchi, Takashi; Sakagami, Hiroyuki; Yoshimura, Yoshiyuki; Miyazawa, Shoko; Nakayama, Kohzo; Saitoh, Fuminori; Zhang, Jing-Ping; Lu, Yonghao; Kondo, Hisatake; Endo, Shogo

    2006-06-01

    We cloned here a full-length cDNA of Dem26[Tian et al. (1999)Mol. Brain Res., 72, 147-157], a member of the low-density lipoprotein (LDL) receptor gene family from the rat brain. We originally named the corresponding protein synaptic LDL receptor-related protein (synLRP) [Tian et al. (2002) Soc. Neurosci. Abstr., 28, 405] and have renamed it LRP4 to accord it systematic nomenclature (GenBank(TM) accession no. AB073317). LRP4 protein interacted with postsynaptic scaffold proteins such as postsynaptic density (PSD)-95 via its C-terminal tail sequence, and associated with N-methyl-D-aspartate (NMDA)-type glutamate receptor subunit. The mRNA of LRP4 was localized to dendrites, as well as somas, of neuronal cells, and the full-length protein of 250 kDa was highly concentrated in the brain and localized to various subcellular compartments in the brain, including synaptic fractions. Immunocytochemical study using cultured cortical neurons suggested surface localization in the neuronal cells both in somas and dendrites. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) phosphorylated the C-terminal cytoplasmic region of LRP4 at Ser1887 and Ser1900, and the phosphorylation at the latter site suppressed the interaction of the protein with PSD-95 and synapse-associated protein 97 (SAP97). These findings suggest a postsynaptic role for LRP4, a putative endocytic multiligand receptor, and a mechanism in which CaMKII regulates PDZ-dependent protein-protein interactions and receptor dynamics.

  11. Dopamine receptor D1 and postsynaptic density gene variants associate with opiate abuse and striatal expression levels.

    Science.gov (United States)

    Jacobs, M M; Ökvist, A; Horvath, M; Keller, E; Bannon, M J; Morgello, S; Hurd, Y L

    2013-11-01

    Opioid drugs are highly addictive and their abuse has a strong genetic load. Dopamine-glutamate interactions are hypothesized to be important for regulating neural systems central for addiction vulnerability. Balanced dopamine-glutamate interaction is mediated through several functional associations, including a physical link between discs, large homolog 4 (Drosophila) (DLG4, PSD-95) and dopamine receptor 1 (DRD1) within the postsynaptic density to regulate DRD1 trafficking. To address whether genetic associations with heroin abuse exist in relation to dopamine and glutamate and their potential interactions, we evaluated single-nucleotide polymorphisms of key genes within these systems in three populations of opiate abusers and controls, totaling 489 individuals from Europe and the United States. Despite significant differences in racial makeup of the separate samples, polymorphisms of DRD1 and DLG4 were found to be associated with opiate abuse. In addition, a strong gene-gene interaction between homer 1 homolog (Drosophila) (HOMER1) and DRD1 was predicted to occur in Caucasian subjects. This interaction was further analyzed by evaluating DRD1 genotype in relation to HOMER1b/c protein expression in postmortem tissue from a subset of Caucasian subjects. DRD1 rs265973 genotype correlated with HOMER1b/c levels in the striatum, but not cortex or amygdala; the correlation was inversed in opiate abusers as compared with controls. Cumulatively, these results support the hypothesis that there may be significant, genetically influenced interactions between glutamatergic and dopaminergic pathways in opiate abusers.

  12. Male-specific alteration in excitatory post-synaptic development and social interaction in pre-natal valproic acid exposure model of autism spectrum disorder.

    Science.gov (United States)

    Kim, Ki Chan; Kim, Pitna; Go, Hyo Sang; Choi, Chang Soon; Park, Jin Hee; Kim, Hee Jin; Jeon, Se Jin; Dela Pena, Ike Campomayor; Han, Seol-Heui; Cheong, Jae Hoon; Ryu, Jong Hoon; Shin, Chan Young

    2013-03-01

    Autism spectrum disorder (ASD) is a pervasive developmental disorder characterized by three main behavioral symptoms including social deficits, impaired communication, and stereotyped and repetitive behaviors. ASD prevalence shows gender bias to male. Prenatal exposure to valproic acid (VPA), a drug used in epilepsy and bipolar disorder, induces autistic symptoms in both human and rodents. As we reported previously, prenatally VPA-exposed animals at E12 showed impairment in social behavior without any overt reproductive toxicity. Social interactions were not significantly different between male and female rats in control condition. However, VPA-exposed male offspring showed significantly impaired social interaction while female offspring showed only marginal deficits in social interaction. Similar male inclination was observed in hyperactivity behavior induced by VPA. In addition to the ASD-like behavioral phenotype, prenatally VPA-exposed rat offspring shows crooked tail phenotype, which was not different between male and female groups. Both male and female rat showed reduced GABAergic neuronal marker GAD and increased glutamatergic neuronal marker vGluT1 expression. Interestingly, despite of the similar increased expression of vGluT1, post-synaptic marker proteins such as PSD-95 and α-CAMKII expression was significantly elevated only in male offspring. Electron microscopy showed increased number of post-synapse in male but not in female at 4 weeks of age. These results might suggest that the altered glutamatergic neuronal differentiation leads to deranged post-synaptic maturation only in male offspring prenatally exposed to VPA. Consistent with the increased post-synaptic compartment, VPA-exposed male rats showed higher sensitivity to electric shock than VPA-exposed female rats. These results suggest that prenatally VPA-exposed rats show the male preponderance of ASD-like behaviors including defective social interaction similar to human autistic patients, which

  13. High Content Analysis of Hippocampal Neuron-Astrocyte Co-cultures Shows a Positive Effect of Fortasyn Connect on Neuronal Survival and Postsynaptic Maturation

    Directory of Open Access Journals (Sweden)

    Anne-Lieke F. van Deijk

    2017-08-01

    Full Text Available Neuronal and synaptic membranes are composed of a phospholipid bilayer. Supplementation with dietary precursors for phospholipid synthesis –docosahexaenoic acid (DHA, uridine and choline– has been shown to increase neurite outgrowth and synaptogenesis both in vivo and in vitro. A role for multi-nutrient intervention with specific precursors and cofactors has recently emerged in early Alzheimer's disease, which is characterized by decreased synapse numbers in the hippocampus. Moreover, the medical food Souvenaid, containing the specific nutrient combination Fortasyn Connect (FC, improves memory performance in early Alzheimer's disease patients, possibly via maintaining brain connectivity. This suggests an effect of FC on synapses, but the underlying cellular mechanism is not fully understood. Therefore, we investigated the effect of FC (consisting of DHA, eicosapentaenoic acid (EPA, uridine, choline, phospholipids, folic acid, vitamins B12, B6, C and E, and selenium, on synaptogenesis by supplementing it to primary neuron-astrocyte co-cultures, a cellular model that mimics metabolic dependencies in the brain. We measured neuronal developmental processes using high content screening in an automated manner, including neuronal survival, neurite morphology, as well as the formation and maturation of synapses. Here, we show that FC supplementation resulted in increased numbers of neurons without affecting astrocyte number. Furthermore, FC increased postsynaptic PSD95 levels in both immature and mature synapses. These findings suggest that supplementation with FC to neuron-astrocyte co-cultures increased both neuronal survival and the maturation of postsynaptic terminals, which might aid the functional interpretation of FC-based intervention strategies in neurological diseases characterized by neuronal loss and impaired synaptic functioning.

  14. Functional consequences of pre- and postsynaptic expression of synaptic plasticity

    Science.gov (United States)

    Mizusaki, Beatriz E. P.

    2017-01-01

    Growing experimental evidence shows that both homeostatic and Hebbian synaptic plasticity can be expressed presynaptically as well as postsynaptically. In this review, we start by discussing this evidence and methods used to determine expression loci. Next, we discuss the functional consequences of this diversity in pre- and postsynaptic expression of both homeostatic and Hebbian synaptic plasticity. In particular, we explore the functional consequences of a biologically tuned model of pre- and postsynaptically expressed spike-timing-dependent plasticity complemented with postsynaptic homeostatic control. The pre- and postsynaptic expression in this model predicts (i) more reliable receptive fields and sensory perception, (ii) rapid recovery of forgotten information (memory savings), and (iii) reduced response latencies, compared with a model with postsynaptic expression only. Finally, we discuss open questions that will require a considerable research effort to better elucidate how the specific locus of expression of homeostatic and Hebbian plasticity alters synaptic and network computations. This article is part of the themed issue ‘Integrating Hebbian and homeostatic plasticity’. PMID:28093547

  15. Functional consequences of pre- and postsynaptic expression of synaptic plasticity.

    Science.gov (United States)

    Costa, Rui Ponte; Mizusaki, Beatriz E P; Sjöström, P Jesper; van Rossum, Mark C W

    2017-03-05

    Growing experimental evidence shows that both homeostatic and Hebbian synaptic plasticity can be expressed presynaptically as well as postsynaptically. In this review, we start by discussing this evidence and methods used to determine expression loci. Next, we discuss the functional consequences of this diversity in pre- and postsynaptic expression of both homeostatic and Hebbian synaptic plasticity. In particular, we explore the functional consequences of a biologically tuned model of pre- and postsynaptically expressed spike-timing-dependent plasticity complemented with postsynaptic homeostatic control. The pre- and postsynaptic expression in this model predicts (i) more reliable receptive fields and sensory perception, (ii) rapid recovery of forgotten information (memory savings), and (iii) reduced response latencies, compared with a model with postsynaptic expression only. Finally, we discuss open questions that will require a considerable research effort to better elucidate how the specific locus of expression of homeostatic and Hebbian plasticity alters synaptic and network computations.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity'. © 2017 The Authors.

  16. Neuronal synaptic outputs determine the sexual fate of postsynaptic targets.

    Science.gov (United States)

    Nojima, Tetsuya; Kimura, Ken-ichi; Koganezawa, Masayuki; Yamamoto, Daisuke

    2010-05-11

    Synapses mediate inductive interactions for the proper development of pre- and postsynaptic cells: presynaptic electrical activities and synaptic transmission ensure the organization of postsynaptic structures, whereas neurotrophins produced in postsynaptic cells support the survival and enlargement of presynaptic partners. In Drosophila, a motor nerve has been implicated in the induction of the muscle of Lawrence (MOL), the formation of which is male specific and depends on the neural expression of fruitless (fru), a neural sex-determinant gene. Here we report the identification of a single motoneuron essential for inducing the MOL, which we call the MOL-inducing (Mind) motoneuron. The MOL is restored in fru mutant males, which otherwise lack the MOL, if the fru(+) transgene is selectively expressed in the Mind motoneuron by mosaic analysis with a repressible cell marker. We further demonstrate that synaptic outputs from the Mind motoneuron are indispensable to MOL induction, because the blockage of synaptic transmission by shibire(ts) (shi(ts)) during the critical period in development abolished the MOL formation in males. Our finding that sex-specific neurons instruct sexually dimorphic development of their innervating targets through synaptic interactions points to the novel mechanism whereby the pre- and postsynaptic partners coordinately establish their sexual identity. (c) 2010 Elsevier Ltd. All rights reserved.

  17. The microtubule-associated protein 1A (MAP1A) is an early molecular target of soluble Aβ-peptide

    DEFF Research Database (Denmark)

    Clemmensen, C; Aznar, S; Knudsen, G M

    2012-01-01

    ) protein, proposing that microtubule perturbations might be central for the Aβ-induced neuronal dysfunctions as PSD-95 plays a key role in synaptic plasticity. In conclusion, this study suggests that disruption of MAP1A could be a very early manifestation of Aβ-mediated synaptic dysfunction...... that microtubule rearrangements may be proximate to neuritic degeneration and deficits in episodic declarative memory. Here, we examined primary cortical neurons for changes in markers associated with synaptic function following exposure to sublethal concentrations of non-aggregated Aβ-peptide. This data show...... that soluble Aβ species at a sublethal concentration induce degradation of the microtubule-associated protein 1A (MAP1A) without concurrently affecting dendritic marker MAP2 and/or the pre-synaptic marker synaptophysin. In addition, MAP1A was found to highly co-localize with the postsynaptic density-95 (PSD-95...

  18. The calcium sensor synaptotagmin 1 is expressed and regulated in hippocampal postsynaptic spines

    DEFF Research Database (Denmark)

    Hussain, Suleman; Egbenya, Daniel Lawer; Lai, Yi-Chen

    2017-01-01

    vesicles and at the postsynaptic density. We further investigated whether postsynaptic synaptotagmin 1 is regulated during synaptic plasticity. In a rat model of chronic temporal lobe epilepsy, we found that presynaptic and postsynaptic concentrations of the protein are reduced compared to control animals...

  19. Serotoninergic dorsal raphe neurons possess functional postsynaptic nicotinic acetylcholine receptors.

    Science.gov (United States)

    Galindo-Charles, Luis; Hernandez-Lopez, Salvador; Galarraga, Elvira; Tapia, Dagoberto; Bargas, José; Garduño, Julieta; Frías-Dominguez, Carmen; Drucker-Colin, René; Mihailescu, Stefan

    2008-08-01

    Very few neurons in the telencephalon have been shown to express functional postsynaptic nicotinic acetylcholine receptors (nAChRs), among them, the noradrenergic and dopaminergic neurons. However, there is no evidence for postsynaptic nAChRs on serotonergic neurons. In this study, we asked if functional nAChRs are present in serotonergic (5-HT) and nonserotonergic (non-5-HT) neurons of the dorsal raphe nucleus (DRN). In rat midbrain slices, field stimulation at the tegmental pedunculopontine (PPT) nucleus evoked postsynaptic currents (eEPSCs) with different components in DRN neurons. After blocking the glutamatergic and GABAergic components, the remaining eEPSCs were blocked by mecamylamine and reduced by either the selective alpha7 nAChR antagonist methyllycaconitine (MLA) or the selective alpha4beta2 nAChR antagonist dihydro-beta-eritroidine (DHbetaE). Simultaneous addition of MLA and DHbetaE blocked all eEPSCs. Integrity of the PPT-DRN pathway was assessed by both anterograde biocytin tracing and antidromic stimulation from the DRN. Inward currents evoked by the direct application of acetylcholine (ACh), in the presence of atropine and tetrodotoxin, consisted of two kinetically different currents: one was blocked by MLA and the other by DHbetaE; in both 5-HT and non-5-HT DR neurons. Analysis of spontaneous (sEPSCs) and evoked (eEPSCs) synaptic events led to the conclusion that nAChRs were located at the postsynaptic membrane. The possible implications of these newly described nAChRs in various physiological processes and behavioral events, such as the wake-sleep cycle, are discussed.

  20. Towards a quantitative model of the post-synaptic proteome.

    Science.gov (United States)

    Sorokina, Oksana; Sorokin, Anatoly; Armstrong, J Douglas

    2011-10-01

    The postsynaptic compartment of the excitatory glutamatergic synapse contains hundreds of distinct polypeptides with a wide range of functions (signalling, trafficking, cell-adhesion, etc.). Structural dynamics in the post-synaptic density (PSD) are believed to underpin cognitive processes. Although functionally and morphologically diverse, PSD proteins are generally enriched with specific domains, which precisely define the mode of clustering essential for signal processing. We applied a stochastic calculus of domain binding provided by a rule-based modelling approach to formalise the highly combinatorial signalling pathway in the PSD and perform the numerical analysis of the relative distribution of protein complexes and their sizes. We specified the combinatorics of protein interactions in the PSD by rules, taking into account protein domain structure, specific domain affinity and relative protein availability. With this model we interrogated the critical conditions for the protein aggregation into large complexes and distribution of both size and composition. The presented approach extends existing qualitative protein-protein interaction maps by considering the quantitative information for stoichiometry and binding properties for the elements of the network. This results in a more realistic view of the postsynaptic proteome at the molecular level.

  1. Treadmill exercise improves motor and memory functions in cerebral palsy rats through activation of PI3K-Akt pathway

    OpenAIRE

    Jung, Sun-Young; Kim, Dae-Young

    2017-01-01

    Cerebral palsy (CP) is a chronic disorder characterized by physical disability and disruption of brain function. We evaluated the effects of treadmill exercise on motor and memory functions in relation with phosphatidylinositol 3-kinase (PI3K)-Akt pathway using CP rat model. Rota-rod test, step-down avoidance task, 5-bromo-2?-deoxyuridine (BrdU) immunohistochemistry, and western blot for synapsin I, postsynaptic density-95 (PSD-95), PI3K, Akt, and glycogen synthase kinase-3? (GSK-3?) were per...

  2. Regulation of dopamine D1 receptor dynamics within the postsynaptic density of hippocampal glutamate synapses.

    Directory of Open Access Journals (Sweden)

    Laurent Ladepeche

    Full Text Available Dopamine receptor potently modulates glutamate signalling, synaptic plasticity and neuronal network adaptations in various pathophysiological processes. Although key intracellular signalling cascades have been identified, the cellular mechanism by which dopamine and glutamate receptor-mediated signalling interplay at glutamate synapse remain poorly understood. Among the cellular mechanisms proposed to aggregate D1R in glutamate synapses, the direct interaction between D1R and the scaffold protein PSD95 or the direct interaction with the glutamate NMDA receptor (NMDAR have been proposed. To tackle this question we here used high-resolution single nanoparticle imaging since it provides a powerful way to investigate at the sub-micron resolution the dynamic interaction between these partners in live synapses. We demonstrate in hippocampal neuronal networks that dopamine D1 receptors (D1R laterally diffuse within glutamate synapses, in which their diffusion is reduced. Disrupting the interaction between D1R and PSD95, through genetical manipulation and competing peptide, did not affect D1R dynamics in glutamatergic synapses. However, preventing the physical interaction between D1R and the GluN1 subunit of NMDAR abolished the synaptic stabilization of diffusing D1R. Together, these data provide direct evidence that the interaction between D1R and NMDAR in synapses participate in the building of the dopamine-receptor-mediated signalling, and most likely to the glutamate-dopamine cross-talk.

  3. Differential Changes in Postsynaptic Density Proteins in Postmortem Huntington’s Disease and Parkinson’s Disease Human Brains

    Directory of Open Access Journals (Sweden)

    C. Fourie

    2014-01-01

    Full Text Available NMDA and AMPA-type glutamate receptors and their bound membrane-associated guanylate kinases (MAGUKs are critical for synapse development and plasticity. We hypothesised that these proteins may play a role in the changes in synapse function that occur in Huntington’s disease (HD and Parkinson’s disease (PD. We performed immunohistochemical analysis of human postmortem brain tissue to examine changes in the expression of SAP97, PSD-95, GluA2 and GluN1 in human control, and HD- and PD-affected hippocampus and striatum. Significant increases in SAP97 and PSD-95 were observed in the HD and PD hippocampus, and PSD95 was downregulated in HD striatum. We observed a significant increase in GluN1 in the HD hippocampus and a decrease in GluA2 in HD and PD striatum. Parallel immunohistochemistry experiments in the YAC128 mouse model of HD showed no change in the expression levels of these synaptic proteins. Our human data show that major but different changes occur in glutamatergic proteins in HD versus PD human brains. Moreover, the changes in human HD brains differ from those occurring in the YAC128 HD mouse model, suggesting that unique changes occur at a subcellular level in the HD human hippocampus.

  4. SNAP-25, a Known Presynaptic Protein with Emerging Postsynaptic Functions.

    Science.gov (United States)

    Antonucci, Flavia; Corradini, Irene; Fossati, Giuliana; Tomasoni, Romana; Menna, Elisabetta; Matteoli, Michela

    2016-01-01

    A hallmark of synaptic specializations is their dependence on highly organized complexes of proteins that interact with each other. The loss or modification of key synaptic proteins directly affects the properties of such networks, ultimately impacting synaptic function. SNAP-25 is a component of the SNARE complex, which is central to synaptic vesicle exocytosis, and, by directly interacting with different calcium channels subunits, it negatively modulates neuronal voltage-gated calcium channels, thus regulating intracellular calcium dynamics. The SNAP-25 gene has been associated with distinct brain diseases, including Attention Deficit Hyperactivity Disorder (ADHD), schizophrenia and bipolar disorder, indicating that the protein may act as a shared biological substrate among different "synaptopathies". The mechanisms by which alterations in SNAP-25 may concur to these psychiatric diseases are still undefined, although alterations in neurotransmitter release have been indicated as potential causative processes. This review summarizes recent work showing that SNAP-25 not only controls exo/endocytic processes at the presynaptic terminal, but also regulates postsynaptic receptor trafficking, spine morphogenesis, and plasticity, thus opening the possibility that SNAP-25 defects may contribute to psychiatric diseases by impacting not only presynaptic but also postsynaptic functions.

  5. The effects of exercise on learning and memory and on the expression of synaptophysin and postsynaptic density protein 95 in the prefrontal cortex%不同形式的运动训练对血管性痴呆大鼠学习记忆及前额叶皮质区突触素及突触后致密物-95表达的影响

    Institute of Scientific and Technical Information of China (English)

    董军涛; 郑修元; 林阳阳; 燕铁斌; 何晓阔; 赵敬璞; 录欣欣

    2015-01-01

    Objective To study the effects of different types of exercise training on learning and memory, as well as on the expression of synaptophysin (SYP) and on postsynaptic density protein 95 (PSD-95) in rats in which a model of vascular dementia had been created.Methods Forty male Wistar rats were divided randomly into a voluntary exercise group (V-EX) , a forced exercise group (F-EX) , an involuntary exercise group (I-EX) , a vascular dementia group (VD) and a sham-operation group (Sham) , with 8 rats in each group.Two-vessel occlusion (2-VO) of the arteria carotis communis was used to create a model of vascular dementia in all of the rats except those in the sham-operation group.Beginning one week after the surgery, the V-Ex rats were free to run in a running wheel.The F-EX rats were forced to run 270 m a day in an electric wheel.The I-EX rats were stimulated to imitate the gait pattern of their forelimbs running at 9 m/min three times a day for l0 minutes each time.No special training was given to the rats in the other 2 groups.Three weeks after the surgery, their learning and memory were tested using a novel object recognition test.Immediately after the test, their prefrontal cortex was sampled and the expression of SYP and PSD-95 was detected using western blotting.Results The average novel object recognition indices of the rats in the V-EX, F-EX and I-EX groups were all significantly higher than that of the VD group.Average PSD-95 expression was also significandy higher than in the VD group.Conclusion Exercise, whether voluntary, forced or induced by functional electrical stimulation can improve learning and memory in vascular dementia, at least in rats.The mechanism is possibly that the training can increase the expression of PSD-95 in the prefrontal cortex, though not SYP.%目的 研究不同形式的运动训练(自主运动、强迫运动和功能性电刺激诱导的运动)对血管性痴呆(VD)大鼠学习记忆功能的恢复及前额叶皮质区突

  6. Effects of Chronic Stress on Cognition in Male SAMP8 Mice.

    Science.gov (United States)

    Wang, Jinhua; Yuan, Jie; Pang, Jingjuan; Ma, Jiang; Han, Bing; Geng, Yuan; Shen, Li; Wang, Hualong; Ma, Qinying; Wang, Yanyong; Wang, Mingwei

    2016-01-01

    Chronic stress can lead to cognitive impairment. Senescence-accelerated mouse prone 8 (SAMP8) is a naturally occurring animal model that is useful for investigating the neurological mechanisms of Alzheimer's disease. Here we investigated the impact and mechanisms of chronic stress on cognition in male SAMP8 mice. Male 6-month- old SAMP8 and SAMR1 (senescence-accelerated mouse resistant 1) mice strains were randomly divided into 4 groups. Mice in the unpredictable chronic mild stress (UCMS) groups were exposed to diverse stressors for 4 weeks. Then, these mice performed Morris water maze (MWM) test to assess the effect of UCMS on learning and memory. To explore the neurological mechanisms of UCMS on cognition in mice, we evaluated changes in the expression of postsynaptic density 95 (PSD95) and synaptophysin (SYN), which are essential proteins for synaptic plasticity. Five mice from each group were randomly chosen for reverse transcription polymerase chain reaction (RT-PCR) and western blotting analysis of SYN and PSD95. The Morris water maze experiment revealed that the cognitive ability of the SAMP8 mice decreased with brain aging, and that chronic stress aggravated this cognitive deficit. In addition, chronic stress decreased the mRNA and protein expression of SYN and PSD95 in the hippocampus of the SAMP8 mice; however, the SAMR1 mice were unaffected. Our results demonstrate that decreased cognition and synaptic plasticity are related to aging. Moreover, we show that chronic stress aggravated this cognitive deficit and decreased SYN and PSD95 expression in the SAMP8 mice. Furthermore, the SAMP8 mice were more vulnerable to the detrimental effects of chronic stress on cognition than the SAMR1 mice. Our results suggest that the neurological mechanisms of chronic stress on cognition might be associated with a decrease in hippocampal SYN and PSD95 expression, which is critical for structural synaptic plasticity. © 2016 The Author(s) Published by S. Karger AG, Basel.

  7. Effects of Chronic Stress on Cognition in Male SAMP8 Mice

    Directory of Open Access Journals (Sweden)

    Jinhua Wang

    2016-08-01

    Full Text Available Background/Aims: Chronic stress can lead to cognitive impairment. Senescence-accelerated mouse prone 8 (SAMP8 is a naturally occurring animal model that is useful for investigating the neurological mechanisms of Alzheimer's disease. Here we investigated the impact and mechanisms of chronic stress on cognition in male SAMP8 mice. Methods: Male 6-month- old SAMP8 and SAMR1 (senescence-accelerated mouse resistant 1 mice strains were randomly divided into 4 groups. Mice in the unpredictable chronic mild stress (UCMS groups were exposed to diverse stressors for 4 weeks. Then, these mice performed Morris water maze (MWM test to assess the effect of UCMS on learning and memory. To explore the neurological mechanisms of UCMS on cognition in mice, we evaluated changes in the expression of postsynaptic density 95 (PSD95 and synaptophysin (SYN, which are essential proteins for synaptic plasticity. Five mice from each group were randomly chosen for reverse transcription polymerase chain reaction (RT-PCR and western blotting analysis of SYN and PSD95. Results: The Morris water maze experiment revealed that the cognitive ability of the SAMP8 mice decreased with brain aging, and that chronic stress aggravated this cognitive deficit. In addition, chronic stress decreased the mRNA and protein expression of SYN and PSD95 in the hippocampus of the SAMP8 mice; however, the SAMR1 mice were unaffected. Conclusion: Our results demonstrate that decreased cognition and synaptic plasticity are related to aging. Moreover, we show that chronic stress aggravated this cognitive deficit and decreased SYN and PSD95 expression in the SAMP8 mice. Furthermore, the SAMP8 mice were more vulnerable to the detrimental effects of chronic stress on cognition than the SAMR1 mice. Our results suggest that the neurological mechanisms of chronic stress on cognition might be associated with a decrease in hippocampal SYN and PSD95 expression, which is critical for structural synaptic

  8. Identification of proteins in the postsynaptic density fraction by mass spectrometry

    DEFF Research Database (Denmark)

    Walikonis, R S; Jensen, Ole Nørregaard; Mann, M

    2000-01-01

    Our understanding of the organization of postsynaptic signaling systems at excitatory synapses has been aided by the identification of proteins in the postsynaptic density (PSD) fraction, a subcellular fraction enriched in structures with the morphology of PSDs. In this study, we have completed...

  9. Distinct presynaptic and postsynaptic dismantling processes of Drosophila neuromuscular junctions during metamorphosis.

    Science.gov (United States)

    Liu, Zhiwei; Chen, Yan; Wang, Dan; Wang, Songyan; Zhang, Yong Q

    2010-09-01

    Synapse remodeling is a widespread and fundamental process that underlies the formation of neuronal circuitry during development and in adaptation to physiological and/or environmental changes. However, the mechanisms of synapse remodeling are poorly understood. Synapses at the neuromuscular junction (NMJ) in Drosophila larvae undergo dramatic and extensive remodeling during metamorphosis to generate adult-specific synapses. To explore the molecular and cellular processes of synapse elimination, we performed confocal microscopy, live imaging, and electron microscopy (EM) of NMJ synapses during the early stages of metamorphosis in Drosophila in which the expressions of selected genes were genetically altered. We report that the localization of the postsynaptic scaffold protein Disc large (Dlg) becomes diffuse first and then undetectable, as larval muscles undergo histolysis, whereas presynaptic vesicles aggregate and are retrogradely transported along axons in synchrony with the formation of filopodia-like structures along NMJ elaborations and retraction of the presynaptic plasma membrane. EM revealed that the postsynaptic subsynaptic reticulum vacuolizes in the early stages of synapse dismantling concomitant with diffuse localization of Dlg. Ecdysone is the major hormone that drives metamorphosis. Blockade of the ecdysone signaling specifically in presynaptic neurons by expression of a dominant-negative form of ecdysone receptors delayed presynaptic but not postsynaptic dismantling. However, inhibition of ecdysone signaling, as well as ubiquitination pathway or apoptosis specifically in postsynaptic muscles, arrested both presynaptic and postsynaptic dismantling. These results demonstrate that presynaptic and postsynaptic dismantling takes place through different mechanisms and that the postsynaptic side plays an instructive role in synapse dismantling.

  10. Reverberation, storage, and postsynaptic propagation of memories during sleep

    Science.gov (United States)

    Ribeiro, Sidarta; Nicolelis, Miguel A.L.

    2004-01-01

    In mammals and birds, long episodes of nondreaming sleep (“slow-wave” sleep, SW) are followed by short episodes of dreaming sleep (“rapid-eye-movement” sleep, REM). Both SW and REM sleep have been shown to be important for the consolidation of newly acquired memories, but the underlying mechanisms remain elusive. Here we review electrophysiological and molecular data suggesting that SW and REM sleep play distinct and complementary roles on memory consolidation: While postacquisition neuronal reverberation depends mainly on SW sleep episodes, transcriptional events able to promote long-lasting memory storage are only triggered during ensuing REM sleep. We also discuss evidence that the wake-sleep cycle promotes a postsynaptic propagation of memory traces away from the neural sites responsible for initial encoding. Taken together, our results suggest that basic molecular and cellular mechanisms underlie the reverberation, storage, and propagation of memory traces during sleep. We propose that these three processes alone may account for several important properties of memory consolidation over time, such as deeper memory encoding within the cerebral cortex, incremental learning several nights after memory acquisition, and progressive hippocampal disengagement. PMID:15576886

  11. Cooperative Phosphoinositide and Peptide Binding by PSD-95/Discs Large/ZO-1 (PDZ) Domain of Polychaetoid, Drosophila Zonulin*

    Science.gov (United States)

    Ivarsson, Ylva; Wawrzyniak, Anna Maria; Wuytens, Gunther; Kosloff, Mickey; Vermeiren, Elke; Raport, Marie; Zimmermann, Pascale

    2011-01-01

    PDZ domains are well known protein-protein interaction modules that, as part of multidomain proteins, assemble molecular complexes. Some PDZ domains have been reported to interact with membrane lipids, in particular phosphatidylinositol phosphates, but few studies have been aimed at elucidating the prevalence or the molecular details of such interactions. We screened 46 Drosophila PDZ domains for phosphoinositide-dependent cellular localization and discovered that the second PDZ domain of polychaetoid (Pyd PDZ2) interacts with phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) at the plasma membrane. Surface plasmon resonance binding experiments with recombinant protein established that Pyd PDZ2 interacts with phosphatidylinositol phosphates with apparent affinities in the micromolar range. Electrostatic interactions involving an extended positively charged surface of Pyd PDZ2 are crucial for the PtdIns(4,5)P2-dependent membrane interactions as shown by a combination of three-dimensional modeling, mutagenesis, binding, and localization studies. In vivo localization studies further suggested that both lipid and peptide binding contribute to membrane localization. We identified the transmembrane protein Crumbs as a Pyd PDZ2 ligand and probed the relation between peptide and PtdIns(4,5)P2 binding. Contrary to the prevalent view on PDZ/peptide/lipid binding, we did not find competition between peptide and lipid ligands. Instead, preloading the protein with the 10-mer Crb3 peptide increased the apparent affinity of Pyd PDZ2 for PtdIns(4,5)P2 6-fold. Our results suggest that membrane localization of Pyd PDZ2 may be driven by a combination of peptide and PtdIns(4,5)P2 binding, which raises the intriguing possibility that the domain may coordinate protein- and phospholipid-mediated signals. PMID:22033935

  12. Cooperative phosphoinositide and peptide binding by PSD-95/discs large/ZO-1 (PDZ) domain of polychaetoid, Drosophila zonulin.

    Science.gov (United States)

    Ivarsson, Ylva; Wawrzyniak, Anna Maria; Wuytens, Gunther; Kosloff, Mickey; Vermeiren, Elke; Raport, Marie; Zimmermann, Pascale

    2011-12-30

    PDZ domains are well known protein-protein interaction modules that, as part of multidomain proteins, assemble molecular complexes. Some PDZ domains have been reported to interact with membrane lipids, in particular phosphatidylinositol phosphates, but few studies have been aimed at elucidating the prevalence or the molecular details of such interactions. We screened 46 Drosophila PDZ domains for phosphoinositide-dependent cellular localization and discovered that the second PDZ domain of polychaetoid (Pyd PDZ2) interacts with phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)) at the plasma membrane. Surface plasmon resonance binding experiments with recombinant protein established that Pyd PDZ2 interacts with phosphatidylinositol phosphates with apparent affinities in the micromolar range. Electrostatic interactions involving an extended positively charged surface of Pyd PDZ2 are crucial for the PtdIns(4,5)P(2)-dependent membrane interactions as shown by a combination of three-dimensional modeling, mutagenesis, binding, and localization studies. In vivo localization studies further suggested that both lipid and peptide binding contribute to membrane localization. We identified the transmembrane protein Crumbs as a Pyd PDZ2 ligand and probed the relation between peptide and PtdIns(4,5)P(2) binding. Contrary to the prevalent view on PDZ/peptide/lipid binding, we did not find competition between peptide and lipid ligands. Instead, preloading the protein with the 10-mer Crb3 peptide increased the apparent affinity of Pyd PDZ2 for PtdIns(4,5)P(2) 6-fold. Our results suggest that membrane localization of Pyd PDZ2 may be driven by a combination of peptide and PtdIns(4,5)P(2) binding, which raises the intriguing possibility that the domain may coordinate protein- and phospholipid-mediated signals.

  13. Effects of dimeric PSD-95 inhibition on excitotoxic cell death and outcome after controlled cortical impact in rats

    DEFF Research Database (Denmark)

    Sommer, Jens Bak; Bach, Anders; Rytter, Hana Malá

    2017-01-01

    investigated in order to assess uptake of the drug into the central nervous system of rats. After a controlled cortical impact rats were randomized to receive a single injection of either saline or two different doses of UCCB01-144 (10 or 20 mg/kg IV) immediately after injury. Spatial learning and memory were...... assessed in a water maze at two weeks post-trauma, and at four weeks lesion volumes were estimated. Overall, UCCB01-144 did not protect against NMDA-toxicity in neuronal cultures or experimental TBI in rats. Important factors that should be investigated further in future studies assessing the effects...

  14. Protein Crowding within the Postsynaptic Density Can Impede the Escape of Membrane Proteins

    NARCIS (Netherlands)

    Li, TP; Song, Y; Mac Gillavry, H.D.; Blanpied, TA; Raghavachari, S

    2016-01-01

    Mechanisms regulating lateral diffusion and positioning of glutamate receptors within the postsynaptic density (PSD) determine excitatory synaptic strength. Scaffold proteins in the PSD are abundant receptor binding partners, yet electron microscopy suggests that the PSD is highly crowded,

  15. [The correlation between postsynaptic inhibition and GABA, opioid peptides, SP in electroacupuncture].

    Science.gov (United States)

    Fang, Z; Yu, Q; Li, Y

    1993-01-01

    Identified tract cells in lumbar enlargement were recorded from intact anaesthetized rats. The prolongation of the latency of antidromic action potential was a measure of postsynaptic inhibition. Both ST 36 and SP 6 were stimulated electrically. In EA group (N = 12) EA prolonged the latency for 0.111 +/- 0.022 ms (P opioides and SP might be involved in postsynaptic inhibition induced by EA.

  16. Extrasynaptic and postsynaptic receptors in glycinergic and GABAergic neurotransmission: a division of labor?

    Directory of Open Access Journals (Sweden)

    Emilie Muller

    2008-03-01

    Full Text Available Glycine and GABA mediate inhibitory neurotransmission in the spinal cord and central nervous system. The general concept of neurotransmission is now challenged by the contribution of both phasic activation of postsynaptic glycine and GABAA receptors (GlyRs and GABAARs, respectively and tonic activity of these receptors located at extrasynaptic sites. GlyR and GABAAR kinetics depend on several parameters, including subunit composition, subsynaptic localization and activation mode. Postsynaptic and extrasynaptic receptors display different subunit compositions and are activated by fast presynaptic and slow paracrine release of neurotransmitters, respectively. GlyR and GABAAR functional properties also rely on their aggregation level, which is higher at postsynaptic densities than at extrasynaptic loci. Finally, these receptors can co-aggregate at mixed inhibitory postsynaptic densities where they cross-modulate their activity, providing another parameter of functional complexity. GlyR and GABAAR density at postsynaptic sites results from the balance between their internalization and insertion in the plasma membrane, but also on their lateral diffusion from and to the postsynaptic loci. The dynamic exchange of receptors between synaptic and extrasynaptic sites and their functional adaptation in terms of kinetics point out a new adaptive process of inhibitory neurotransmission.

  17. IKK regulates the deubiquitinase CYLD at the postsynaptic density

    Energy Technology Data Exchange (ETDEWEB)

    Thein, Soe; Pham, Anna [Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892 (United States); Bayer, K. Ulrich [Department of Pharmacology, University of Colorado Denver School of Medicine, Aurora, CO 80045 (United States); Tao-Cheng, Jung-Hwa [EM Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892 (United States); Dosemeci, Ayse, E-mail: dosemeca@mail.nih.gov [Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892 (United States)

    2014-07-18

    Highlights: • CYLD is phosphorylated by IKK in isolated PSDs in the absence of Ca{sup 2+}. • CYLD is phosphorylated by IKK at the PSDs of intact neurons in basal conditions. • Phosphorylation of CYLD by IKK increases its deubiquitinase activity. • The process is likely to influence protein trafficking at the PSD in basal conditions. - Abstract: K63-linked polyubiquitination of proteins regulates their trafficking into specific cellular pathways such as endocytosis and autophagy. CYLD, a deubiquitinase specific for K63-linked polyubiquitins, is present in high quantities at the postsynaptic density (PSD). It was previously shown that, under excitatory conditions, CaMKII activates CYLD in a Ca{sup 2+}-dependent manner. The observation that CYLD can also be phosphorylated in the absence of Ca{sup 2+} in isolated PSDs led us to further explore the regulation of CYLD under basal conditions. A possible involvement of the autonomous form of CaMKII and IKK, both kinases known to be localized at the PSD, was examined. A CaMKII inhibitor CN21 had no effect on CYLD phosphorylation in the absence of Ca{sup 2+}, but two different IKK inhibitors, IKK16 and tatNEMO, inhibited its phosphorylation. Immuno-electron microscopy on hippocampal cultures, using an antibody for CYLD phosphorylated at S-418, revealed that the phosphorylated form of CYLD is present at the PSD under basal conditions. Phosphorylation of CYLD under basal conditions was inhibited by IKK16. NMDA treatment further promoted phosphorylation of CYLD at the PSD, but IKK16 failed to block the NMDA-induced effect. In vitro experiments using purified proteins demonstrated direct phosphorylation and activation of CYLD by the beta catalytic subunit of IKK. Activation of IKK in isolated PSDs also promoted phosphorylation of CYLD and an increase in endogenous deubiquitinase activity for K63-linked polyubiquitins. Altogether, the results suggest that in the absence of excitatory conditions, constitutive IKK activity

  18. Estimating short-term synaptic plasticity from pre- and postsynaptic spiking.

    Directory of Open Access Journals (Sweden)

    Abed Ghanbari

    2017-09-01

    Full Text Available Short-term synaptic plasticity (STP critically affects the processing of information in neuronal circuits by reversibly changing the effective strength of connections between neurons on time scales from milliseconds to a few seconds. STP is traditionally studied using intracellular recordings of postsynaptic potentials or currents evoked by presynaptic spikes. However, STP also affects the statistics of postsynaptic spikes. Here we present two model-based approaches for estimating synaptic weights and short-term plasticity from pre- and postsynaptic spike observations alone. We extend a generalized linear model (GLM that predicts postsynaptic spiking as a function of the observed pre- and postsynaptic spikes and allow the connection strength (coupling term in the GLM to vary as a function of time based on the history of presynaptic spikes. Our first model assumes that STP follows a Tsodyks-Markram description of vesicle depletion and recovery. In a second model, we introduce a functional description of STP where we estimate the coupling term as a biophysically unrestrained function of the presynaptic inter-spike intervals. To validate the models, we test the accuracy of STP estimation using the spiking of pre- and postsynaptic neurons with known synaptic dynamics. We first test our models using the responses of layer 2/3 pyramidal neurons to simulated presynaptic input with different types of STP, and then use simulated spike trains to examine the effects of spike-frequency adaptation, stochastic vesicle release, spike sorting errors, and common input. We find that, using only spike observations, both model-based methods can accurately reconstruct the time-varying synaptic weights of presynaptic inputs for different types of STP. Our models also capture the differences in postsynaptic spike responses to presynaptic spikes following short vs long inter-spike intervals, similar to results reported for thalamocortical connections. These models may

  19. Postsynaptic GABAB receptors enhance extrasynaptic GABAA receptor function in dentate gyrus granule cells.

    Science.gov (United States)

    Tao, Wucheng; Higgs, Matthew H; Spain, William J; Ransom, Christopher B

    2013-02-27

    Ambient GABA in the brain tonically activates extrasynaptic GABA(A) receptors, and activity-dependent changes in ambient GABA concentration can also activate GABA(B) receptors. To investigate an interaction between postsynaptic GABA(B) and GABA(A) receptors, we recorded GABA(A) currents elicited by exogenous GABA (10 μm) from dentate gyrus granule cells (DGGCs) in adult rat hippocampal slices. The GABA(B) receptor agonist baclofen (20 μm) enhanced GABA(A) currents. This enhancement was blocked by the GABA(B) receptor antagonist CGP 55845 and intracellular solutions containing the GTP analog GDP-β-s, indicating that baclofen was acting on postsynaptic GABA(B) receptors. Modulation of GABA(A) currents by postsynaptic GABA(B) receptors was not observed in CA1 pyramidal cells or layer 2/3 cortical pyramidal neurons. Baclofen reduced the frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) but did not alter sIPSC amplitude or kinetics. Thus, GABA(A) receptors activated at synapses were not modulated by postsynaptic GABA(B) receptors. In contrast, tonic GABA currents and currents activated by the GABA(A) receptor δ subunit-selective agonist THIP (10 μm) were potentiated by baclofen. Our data indicate that postsynaptic GABA(B) receptors enhance the function of extrasynaptic GABA(A) receptors, including δ subunit-containing receptors that mediate tonic inhibition in DGGCs. The modulation of GABA(A) receptor function by postsynaptic GABA(B) receptors is a newly identified mechanism that will influence the inhibitory tone of DGGCs when GABA(B) and GABA(A) receptors are both activated.

  20. Estimating short-term synaptic plasticity from pre- and postsynaptic spiking

    Science.gov (United States)

    Malyshev, Aleksey; Stevenson, Ian H.

    2017-01-01

    Short-term synaptic plasticity (STP) critically affects the processing of information in neuronal circuits by reversibly changing the effective strength of connections between neurons on time scales from milliseconds to a few seconds. STP is traditionally studied using intracellular recordings of postsynaptic potentials or currents evoked by presynaptic spikes. However, STP also affects the statistics of postsynaptic spikes. Here we present two model-based approaches for estimating synaptic weights and short-term plasticity from pre- and postsynaptic spike observations alone. We extend a generalized linear model (GLM) that predicts postsynaptic spiking as a function of the observed pre- and postsynaptic spikes and allow the connection strength (coupling term in the GLM) to vary as a function of time based on the history of presynaptic spikes. Our first model assumes that STP follows a Tsodyks-Markram description of vesicle depletion and recovery. In a second model, we introduce a functional description of STP where we estimate the coupling term as a biophysically unrestrained function of the presynaptic inter-spike intervals. To validate the models, we test the accuracy of STP estimation using the spiking of pre- and postsynaptic neurons with known synaptic dynamics. We first test our models using the responses of layer 2/3 pyramidal neurons to simulated presynaptic input with different types of STP, and then use simulated spike trains to examine the effects of spike-frequency adaptation, stochastic vesicle release, spike sorting errors, and common input. We find that, using only spike observations, both model-based methods can accurately reconstruct the time-varying synaptic weights of presynaptic inputs for different types of STP. Our models also capture the differences in postsynaptic spike responses to presynaptic spikes following short vs long inter-spike intervals, similar to results reported for thalamocortical connections. These models may thus be useful

  1. Influence of catch up growth on spatial learning and memory in a mouse model of intrauterine growth restriction.

    Directory of Open Access Journals (Sweden)

    Cristina Duran Fernandez-Feijoo

    Full Text Available Intrauterine growth restriction (IUGR and rapid postnatal weight gain or catch up growth (CUG increase the susceptibility to metabolic syndrome during adult life. Longitudinal studies have also revealed a high incidence of learning difficulties in children with IUGR. The aim of the present study was to investigate the effect of nutrition and CUG on learning memory in an IUGR animal model. We hypothesized that synaptic protein expression and transcription, an essential mechanism for memory consolidation, might be affected by intrauterine undernutrition.IUGR was induced by 50% maternal caloric undernutrition throughout late gestation. During the suckling period, dams were either fed ad libitum or food restricted. The pups were divided into: Normal prenatal diet-Normal postnatal diet (NN, Restricted prenatal diet- Normal postnatal diet + catch up growth (RN+, Normal prenatal diet-Restricted postnatal diet (NR and Restricted prenatal diet-Restricted postnatal diet (RR. At 4 weeks of age, memory was assessed via a water maze test. To evaluate synaptic function, 2 specific synaptic proteins (postsynaptic density-95 [PSD95], synaptophysin as well as insulin receptors (IR were tested by Western Blot and quantitative polymerase chain reaction (qPCR. Brain-derived neurotrophic factor and serum insulin levels were also studied.The RN+ group presented a learning curve similar to the NN animals. The RR animals without CUG showed learning disabilities. PSD95 was lower in the RR group than in the NN and RN+ mice. In contrast, synaptophysin was similar in all groups. IR showed an inverse expression pattern to that of the PSD95. In conclusion, perinatal nutrition plays an important role in learning. CUG after a period of prenatal malnutrition seems to improve learning skills. The functional alterations observed might be related to lower PSD95 activity and a possible dysfunction in the hormone regulation of synaptic plasticity.

  2. The knockdown of αkap alters the postsynaptic apparatus of neuromuscular junctions in living mice.

    Science.gov (United States)

    Martinez-Pena Y Valenzuela, Isabel; Aittaleb, Mohamed; Chen, Po-Ju; Akaaboune, Mohammed

    2015-04-01

    A muscle-specific nonkinase anchoring protein (αkap), encoded within the calcium/calmodulin kinase II (camk2) α gene, was recently found to control the stability of acetylcholine receptor (AChR) clusters on the surface of cultured myotubes. However, it remains unknown whether this protein has any effect on receptor stability and the maintenance of the structural integrity of neuromuscular synapses in vivo. By knocking down the endogenous expression of αkap in mouse sternomastoid muscles with shRNA, we found that the postsynaptic receptor density was dramatically reduced, the turnover rate of receptors at synaptic sites was significantly increased, and the insertion rates of both newly synthesized and recycled receptors into the postsynaptic membrane were depressed. Moreover, we found that αkap shRNA knockdown impaired synaptic structure as postsynaptic AChR clusters and their associated postsynaptic scaffold proteins within the neuromuscular junction were completely eliminated. These results provide new mechanistic insight into the role of αkap in regulating the stability of the postsynaptic apparatus of neuromuscular synapses. Copyright © 2015 the authors 0270-6474/15/355118-10$15.00/0.

  3. PET measures of pre- and post-synaptic cardiac beta adrenergic function

    Energy Technology Data Exchange (ETDEWEB)

    Link, Jeanne M.; Stratton, John R.; Levy, Wayne; Poole, Jeanne E.; Shoner, Steven C.; Stuetzle, Werner; Caldwell, James H. E-mail: jcald@u.washington.edu

    2003-11-01

    Positron Emission Tomography was used to measure global and regional cardiac {beta}-adrenergic function in 19 normal subjects and 9 congestive heart failure patients. [{sup 11}C]-meta-hydroxyephedrine was used to image norepinephrine transporter function as an indicator of pre-synaptic function and [{sup 11}C]-CGP12177 was used to measure cell surface {beta}-receptor density as an indicator of post-synaptic function. Pre-synaptic, but not post-synaptic, function was significantly different between normals and CHF patients. Pre-synaptic function was well matched to post-synaptic function in the normal hearts but significantly different and poorly matched in the CHF patients studied. This imaging technique can help us understand regional sympathetic function in cardiac disease.

  4. Aging alters the molecular dynamics of synapses in a sexually dimorphic pattern in zebrafish (Danio rerio).

    Science.gov (United States)

    Karoglu, Elif Tugce; Halim, Dilara Ozge; Erkaya, Bahriye; Altaytas, Ferda; Arslan-Ergul, Ayca; Konu, Ozlen; Adams, Michelle M

    2017-06-01

    The zebrafish has become a popular model for studying normal brain aging due to its large fecundity, conserved genome, and available genetic tools; but little data exists about neurobiological age-related alterations. The current study tested the hypothesis of an association between brain aging and synaptic protein loss across males and females. Western blot analysis of synaptophysin (SYP), a presynaptic vesicle protein, and postsynaptic density-95 (PSD-95) and gephyrin (GEP), excitatory and inhibitory postsynaptic receptor-clustering proteins, respectively, was performed in young, middle-aged, and old male and female zebrafish (Danio rerio) brains. Univariate and multivariate analyses demonstrated that PSD-95 significantly increased in aged females and SYP significantly decreased in males, but GEP was stable. Thus, these key synaptic proteins vary across age in a sexually dimorphic manner, which has been observed in other species, and these consequences may represent selective vulnerabilities for aged males and females. These data expand our knowledge of normal aging in zebrafish, as well as further establish this model as an appropriate one for examining human brain aging. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Modulation of Central Synapses by Astrocyte-Released ATP and Postsynaptic P2X Receptors

    Science.gov (United States)

    Pankratov, Yuriy

    2017-01-01

    Communication between neuronal and glial cells is important for neural plasticity. P2X receptors are ATP-gated cation channels widely expressed in the brain where they mediate action of extracellular ATP released by neurons and/or glia. Recent data show that postsynaptic P2X receptors underlie slow neuromodulatory actions rather than fast synaptic transmission at brain synapses. Here, we review these findings with a particular focus on the release of ATP by astrocytes and the diversity of postsynaptic P2X-mediated modulation of synaptic strength and plasticity in the CNS. PMID:28845311

  6. NMDA-induced accumulation of Shank at the postsynaptic density is mediated by CaMKII

    Energy Technology Data Exchange (ETDEWEB)

    Tao-Cheng, Jung-Hwa [EM Facility, NINDS, NIH, Bethesda, MD (United States); Yang, Yijung [Laboratory of Neurobiology, NINDS, NIH, Bethesda, MD (United States); Bayer, K. Ulrich [Department of Pharmacology, University of Colorado Denver, School of Medicine, Aurora, CO (United States); Reese, Thomas S. [Laboratory of Neurobiology, NINDS, NIH, Bethesda, MD (United States); Dosemeci, Ayse, E-mail: dosemeca@ninds.nih.gov [Laboratory of Neurobiology, NINDS, NIH, Bethesda, MD (United States)

    2014-07-18

    Highlights: • NMDA-induces accumulation of Shank at the postsynaptic density. • Shank accumulation is preferential to the distal region of the postsynaptic density. • Shank accumulation is mediated by CaMKII. - Abstract: Shank is a specialized scaffold protein present in high abundance at the postsynaptic density (PSD). Using pre-embedding immunogold electron microscopy on cultured hippocampal neurons, we had previously demonstrated further accumulation of Shank at the PSD under excitatory conditions. Here, using the same experimental protocol, we demonstrate that a cell permeable CaMKII inhibitor, tatCN21, blocks NMDA-induced accumulation of Shank at the PSD. Furthermore we show that NMDA application changes the distribution pattern of Shank at the PSD, promoting a 7–10 nm shift in the median distance of Shank labels away from the postsynaptic membrane. Inhibition of CaMKII with tatCN21 also blocks this shift in the distribution of Shank. Altogether these results imply that upon activation of NMDA receptors, CaMKII mediates accumulation of Shank, preferentially at the distal regions of the PSD complex extending toward the cytoplasm.

  7. Pre- and postsynaptic effects of brimonidine on isolated rabbit iris dilator muscles

    Directory of Open Access Journals (Sweden)

    Tatsui S

    2016-05-01

    Full Text Available Sonoko Tatsui,1 Hitoshi Ishikawa,2 Kimiya Shimizu,1 Kimiyo Mashimo1 1Department of Ophthalmology, School of Medicine, Kitasato University, 2Department of Orthoptics and Visual Sciences, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan Purpose: Brimonidine is an imidazoline compound used for the treatment of glaucoma, but having very little effect on pupil diameter. Like para-aminoclonidine, most imidazoline compounds interact with postsynaptic α-adrenoceptors and cause pupil dilatation. Therefore, as part of an investigation of the mechanism of action of brimonidine on pupil diameter, the present study was initiated to measure, in vitro, the relative potency of brimonidine on the pre- and postsynaptic α-adrenoceptors of rabbit iris dilator muscle. Methods: The contractile activity of brimonidine and its effect on twitch contraction evoked by electrical field stimulation were studied in isolated rabbit iris dilator muscles by isometric tension recording. Results: Brimonidine significantly inhibited the twitch contraction of the dilator muscle caused by field stimulation, without affecting the response to exogenously applied phenylephrine. Compared to phenylephrine, brimonidine caused only a small contractile response with % maximum contraction values of<10%. Conclusion: These results suggest that brimonidine may act on nerve endings to inhibit adrenergic neurotransmission with very little effect on postsynaptic α-adrenoceptors. This may indicate that brimonidine reduced the pupil diameter just a little, thus improving night vision. Keywords: brimonidine, rabbit iris dilator, electrical field stimulation, presynaptic α2-adrenoceptor, postsynaptic α1-adrenoceptor, imidazolin

  8. Spike Train Auto-Structure Impacts Post-Synaptic Firing and Timing-Based Plasticity

    Science.gov (United States)

    Scheller, Bertram; Castellano, Marta; Vicente, Raul; Pipa, Gordon

    2011-01-01

    Cortical neurons are typically driven by several thousand synapses. The precise spatiotemporal pattern formed by these inputs can modulate the response of a post-synaptic cell. In this work, we explore how the temporal structure of pre-synaptic inhibitory and excitatory inputs impact the post-synaptic firing of a conductance-based integrate and fire neuron. Both the excitatory and inhibitory input was modeled by renewal gamma processes with varying shape factors for modeling regular and temporally random Poisson activity. We demonstrate that the temporal structure of mutually independent inputs affects the post-synaptic firing, while the strength of the effect depends on the firing rates of both the excitatory and inhibitory inputs. In a second step, we explore the effect of temporal structure of mutually independent inputs on a simple version of Hebbian learning, i.e., hard bound spike-timing-dependent plasticity. We explore both the equilibrium weight distribution and the speed of the transient weight dynamics for different mutually independent gamma processes. We find that both the equilibrium distribution of the synaptic weights and the speed of synaptic changes are modulated by the temporal structure of the input. Finally, we highlight that the sensitivity of both the post-synaptic firing as well as the spike-timing-dependent plasticity on the auto-structure of the input of a neuron could be used to modulate the learning rate of synaptic modification. PMID:22203800

  9. A postsynaptic PI3K-cII dependent signaling controller for presynaptic homeostatic plasticity

    Science.gov (United States)

    Hauswirth, Anna G; Ford, Kevin J; Wang, Tingting; Fetter, Richard D; Tong, Amy

    2018-01-01

    Presynaptic homeostatic plasticity stabilizes information transfer at synaptic connections in organisms ranging from insect to human. By analogy with principles of engineering and control theory, the molecular implementation of PHP is thought to require postsynaptic signaling modules that encode homeostatic sensors, a set point, and a controller that regulates transsynaptic negative feedback. The molecular basis for these postsynaptic, homeostatic signaling elements remains unknown. Here, an electrophysiology-based screen of the Drosophila kinome and phosphatome defines a postsynaptic signaling platform that includes a required function for PI3K-cII, PI3K-cIII and the small GTPase Rab11 during the rapid and sustained expression of PHP. We present evidence that PI3K-cII localizes to Golgi-derived, clathrin-positive vesicles and is necessary to generate an endosomal pool of PI(3)P that recruits Rab11 to recycling endosomal membranes. A morphologically distinct subdivision of this platform concentrates postsynaptically where we propose it functions as a homeostatic controller for retrograde, trans-synaptic signaling. PMID:29303480

  10. Optical Dissection of Experience-Dependent Pre- and Postsynaptic Plasticity in the Drosophila Brain

    Directory of Open Access Journals (Sweden)

    Ulrike Pech

    2015-03-01

    Full Text Available Drosophila represents a key model organism for dissecting neuronal circuits that underlie innate and adaptive behavior. However, this task is limited by a lack of tools to monitor physiological parameters of spatially distributed, central synapses in identified neurons. We generated transgenic fly strains that express functional fluorescent reporters targeted to either pre- or postsynaptic compartments. Presynaptic Ca2+ dynamics are monitored using synaptophysin-coupled GCaMP3, synaptic transmission is monitored using red fluorescent synaptophysin-pHTomato, and postsynaptic Ca2+ dynamics are visualized using GCaMP3 fused with the postsynaptic matrix protein, dHomer. Using two-photon in vivo imaging of olfactory projection neurons, odor-evoked activity across populations of synapses is visualized in the antennal lobe and the mushroom body calyx. Prolonged odor exposure causes odor-specific and differential experience-dependent changes in pre- and postsynaptic activity at both levels of olfactory processing. The approach advances the physiological analysis of synaptic connections across defined groups of neurons in intact Drosophila.

  11. Striatal pre- and postsynaptic profile of adenosine A(2A receptor antagonists.

    Directory of Open Access Journals (Sweden)

    Marco Orru

    2011-01-01

    Full Text Available Striatal adenosine A(2A receptors (A(2ARs are highly expressed in medium spiny neurons (MSNs of the indirect efferent pathway, where they heteromerize with dopamine D(2 receptors (D(2Rs. A(2ARs are also localized presynaptically in cortico-striatal glutamatergic terminals contacting MSNs of the direct efferent pathway, where they heteromerize with adenosine A(1 receptors (A(1Rs. It has been hypothesized that postsynaptic A(2AR antagonists should be useful in Parkinson's disease, while presynaptic A(2AR antagonists could be beneficial in dyskinetic disorders, such as Huntington's disease, obsessive-compulsive disorders and drug addiction. The aim or this work was to determine whether selective A(2AR antagonists may be subdivided according to a preferential pre- versus postsynaptic mechanism of action. The potency at blocking the motor output and striatal glutamate release induced by cortical electrical stimulation and the potency at inducing locomotor activation were used as in vivo measures of pre- and postsynaptic activities, respectively. SCH-442416 and KW-6002 showed a significant preferential pre- and postsynaptic profile, respectively, while the other tested compounds (MSX-2, SCH-420814, ZM-241385 and SCH-58261 showed no clear preference. Radioligand-binding experiments were performed in cells expressing A(2AR-D(2R and A(1R-A(2AR heteromers to determine possible differences in the affinity of these compounds for different A(2AR heteromers. Heteromerization played a key role in the presynaptic profile of SCH-442416, since it bound with much less affinity to A(2AR when co-expressed with D(2R than with A(1R. KW-6002 showed the best relative affinity for A(2AR co-expressed with D(2R than co-expressed with A(1R, which can at least partially explain the postsynaptic profile of this compound. Also, the in vitro pharmacological profile of MSX-2, SCH-420814, ZM-241385 and SCH-58261 was is in accordance with their mixed pre- and postsynaptic profile

  12. Postsynaptic mechanisms underlying the excitatory action of histamine on medial vestibular nucleus neurons in rats

    Science.gov (United States)

    Zhang, Xiao-Yang; Yu, Lei; Zhuang, Qian-Xing; Peng, Shi-Yu; Zhu, Jing-Ning; Wang, Jian-Jun

    2013-01-01

    Background and Purpose Anti-histaminergic drugs have been widely used in the clinical treatment of vestibular disorders and most studies concentrate on their presynaptic actions. The present study investigated the postsynaptic effect of histamine on medial vestibular nucleus (MVN) neurons and the underlying mechanisms. Experimental Approach Histamine-induced postsynaptic actions on MVN neurons and the corresponding receptor and ionic mechanisms were detected by whole-cell patch-clamp recordings on rat brain slices. The distribution of postsynaptic histamine H1, H2 and H4 receptors was mapped by double and single immunostaining. Furthermore, the expression of mRNAs for H1, H2 and H4 receptors and for subtypes of Na+–Ca2+ exchangers (NCXs) and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels was assessed by quantitative real-time RT-PCR. Key Results A marked postsynaptic excitatory effect, co-mediated by histamine H1 and H2 receptors, was involved in the histamine-induced depolarization of MVN neurons. Postsynaptic H1 and H2 rather than H4 receptors were co-localized in the same MVN neurons. NCXs contributed to the inward current mediated by H1 receptors, whereas HCN channels were responsible for excitation induced by activation of H2 receptors. Moreover, NCX1 and NCX3 rather than NCX2, and HCN1 rather than HCN2-4 mRNAs, were abundantly expressed in MVN. Conclusion and Implications NCXs coupled to H1 receptors and HCN channels linked to H2 receptors co-mediate the strong postsynaptic excitatory action of histamine on MVN neurons. These results highlight an active role of postsynaptic mechanisms in the modulation by central histaminergic systems of vestibular functions and suggest potential targets for clinical treatment of vestibular disorders. Linked Articles This article is part of a themed issue on Histamine Pharmacology Update. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2013.170.issue-1 PMID:23713466

  13. Therapeutic testosterone administration preserves excitatory synaptic transmission in the hippocampus during autoimmune demyelinating disease.

    Science.gov (United States)

    Ziehn, Marina O; Avedisian, Andrea A; Dervin, Shannon M; Umeda, Elizabeth A; O'Dell, Thomas J; Voskuhl, Rhonda R

    2012-09-05

    Over 50% of multiple sclerosis (MS) patients experience cognitive deficits, and hippocampal-dependent memory impairment has been reported in >30% of these patients. While postmortem pathology studies and in vivo magnetic resonance imaging demonstrate that the hippocampus is targeted in MS, the neuropathology underlying hippocampal dysfunction remains unknown. Furthermore, there are no treatments available to date to effectively prevent neurodegeneration and associated cognitive dysfunction in MS. We have recently demonstrated that the hippocampus is also targeted in experimental autoimmune encephalomyelitis (EAE), the most widely used animal model of MS. The objective of this study was to assess whether a candidate treatment (testosterone) could prevent hippocampal synaptic dysfunction and underlying pathology when administered in either a preventative or a therapeutic (postdisease induction) manner. Electrophysiological studies revealed impairments in basal excitatory synaptic transmission that involved both AMPA receptor-mediated changes in synaptic currents, and faster decay rates of NMDA receptor-mediated currents in mice with EAE. Neuropathology revealed atrophy of the pyramidal and dendritic layers of hippocampal CA1, decreased presynaptic (Synapsin-1) and postsynaptic (postsynaptic density 95; PSD-95) staining, diffuse demyelination, and microglial activation. Testosterone treatment administered either before or after disease induction restores excitatory synaptic transmission as well as presynaptic and postsynaptic protein levels within the hippocampus. Furthermore, cross-modality correlations demonstrate that fluctuations in EPSPs are significantly correlated to changes in postsynaptic protein levels and suggest that PSD-95 is a neuropathological substrate to impaired synaptic transmission in the hippocampus during EAE. This is the first report demonstrating that testosterone is a viable therapeutic treatment option that can restore both hippocampal

  14. Pre- and postsynaptic effects of brimonidine on isolated rabbit iris dilator muscles

    OpenAIRE

    Tatsui S; Ishikawa H; Shimizu K; Mashimo K

    2016-01-01

    Sonoko Tatsui,1 Hitoshi Ishikawa,2 Kimiya Shimizu,1 Kimiyo Mashimo1 1Department of Ophthalmology, School of Medicine, Kitasato University, 2Department of Orthoptics and Visual Sciences, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan Purpose: Brimonidine is an imidazoline compound used for the treatment of glaucoma, but having very little effect on pupil diameter. Like para-aminoclonidine, most imidazoline compounds interact with postsynaptic α-adrenocepto...

  15. The Drosophila Postsynaptic DEG/ENaC Channel ppk29 Contributes to Excitatory Neurotransmission.

    Science.gov (United States)

    Hill, Alexis; Zheng, Xingguo; Li, Xiling; McKinney, Ross; Dickman, Dion; Ben-Shahar, Yehuda

    2017-03-22

    The protein family of degenerin/epithelial sodium channels (DEG/ENaCs) is composed of diverse animal-specific, non-voltage-gated ion channels that play important roles in regulating cationic gradients across epithelial barriers. Some family members are also enriched in neural tissues in both vertebrates and invertebrates. However, the specific neurophysiological functions of most DEG/ENaC-encoding genes remain poorly understood. The fruit fly Drosophila melanogaster is an excellent model for deciphering the functions of DEG/ENaC genes because its genome encodes an exceptionally large number of DEG/ENaC subunits termed pickpocket (ppk) 1-31 Here we demonstrate that ppk29 contributes specifically to the postsynaptic modulation of excitatory synaptic transmission at the larval neuromuscular junction. Electrophysiological data indicate that the function of ppk29 in muscle is necessary for normal postsynaptic responsivity to neurotransmitter release and for normal coordinated larval movement. The ppk29 mutation does not affect gross synaptic morphology and ultrastructure, which indicates that the observed phenotypes are likely due to defects in glutamate receptor function. Together, our data indicate that DEG/ENaC ion channels play a fundamental role in the postsynaptic regulation of excitatory neurotransmission.SIGNIFICANCE STATEMENT Members of the degenerin/epithelial sodium channel (DEG/ENaC) family are broadly expressed in epithelial and neuronal tissues. To date, the neurophysiological functions of most family members remain unknown. Here, by using the power of Drosophila genetics in combination with electrophysiological and behavioral approaches, we demonstrate that the DEG/ENaC-encoding gene pickpocket 29 contributes to baseline neurotransmission, possibly via the modulation of postsynaptic glutamate receptor functionality. Copyright © 2017 the authors 0270-6474/17/373171-10$15.00/0.

  16. Selective block of postsynaptic kainate receptors reveals their function at hippocampal mossy fiber synapses.

    Science.gov (United States)

    Pinheiro, Paulo S; Lanore, Frédéric; Veran, Julien; Artinian, Julien; Blanchet, Christophe; Crépel, Valérie; Perrais, David; Mulle, Christophe

    2013-02-01

    Progress in understanding the roles of kainate receptors (KARs) in synaptic integration, synaptic networks, and higher brain function has been hampered by the lack of selective pharmacological tools. We have found that UBP310 and related willardiine derivatives, previously characterized as selective GluK1 and GluK3 KAR antagonists, block postsynaptic KARs at hippocampal mossy fiber (MF) CA3 synapses while sparing AMPA and NMDA receptors. We further show that UBP310 is an antagonist of recombinant GluK2/GluK5 receptors, the major population of KARs in the brain. Postsynaptic KAR receptor blockade at MF synapses significantly reduces the sustained depolarization, which builds up during repetitive activity, and impacts on spike transmission mediated by heterosynaptic signals. In addition, KARs present in aberrant MF synapses in the epileptic hippocampus were also blocked by UBP310. Our results support a specific role for postsynaptic KARs in synaptic integration of CA3 pyramidal cells and describe a tool that will be instrumental in understanding the physiopathological role of KARs in the brain.

  17. Calmodulin activation by calcium transients in the postsynaptic density of dendritic spines.

    Directory of Open Access Journals (Sweden)

    Daniel X Keller

    2008-04-01

    Full Text Available The entry of calcium into dendritic spines can trigger a sequence of biochemical reactions that begins with the activation of calmodulin (CaM and ends with long-term changes to synaptic strengths. The degree of activation of CaM can depend on highly local elevations in the concentration of calcium and the duration of transient increases in calcium concentration. Accurate measurement of these local changes in calcium is difficult because the spaces are so small and the numbers of molecules are so low. We have therefore developed a Monte Carlo model of intracellular calcium dynamics within the spine that included calcium binding proteins, calcium transporters and ion channels activated by voltage and glutamate binding. The model reproduced optical recordings using calcium indicator dyes and showed that without the dye the free intracellular calcium concentration transient was much higher than predicted from the fluorescent signal. Excitatory postsynaptic potentials induced large, long-lasting calcium gradients across the postsynaptic density, which activated CaM. When glutamate was released at the synapse 10 ms before an action potential occurred, simulating activity patterns that strengthen hippocampal synapses, the calcium gradient and activation of CaM in the postsynaptic density were much greater than when the order was reversed, a condition that decreases synaptic strengths, suggesting a possible mechanism underlying the induction of long-term changes in synaptic strength. The spatial and temporal mechanisms for selectivity in CaM activation demonstrated here could be used in other signaling pathways.

  18. Laminins promote postsynaptic maturation by an autocrine mechanism at the neuromuscular junction.

    Science.gov (United States)

    Nishimune, Hiroshi; Valdez, Gregorio; Jarad, George; Moulson, Casey L; Müller, Ulrich; Miner, Jeffrey H; Sanes, Joshua R

    2008-09-22

    A prominent feature of synaptic maturation at the neuromuscular junction (NMJ) is the topological transformation of the acetylcholine receptor (AChR)-rich postsynaptic membrane from an ovoid plaque into a complex array of branches. We show here that laminins play an autocrine role in promoting this transformation. Laminins containing the alpha4, alpha5, and beta2 subunits are synthesized by muscle fibers and concentrated in the small portion of the basal lamina that passes through the synaptic cleft at the NMJ. Topological maturation of AChR clusters was delayed in targeted mutant mice lacking laminin alpha5 and arrested in mutants lacking both alpha4 and alpha5. Analysis of chimeric laminins in vivo and of mutant myotubes cultured aneurally demonstrated that the laminins act directly on muscle cells to promote postsynaptic maturation. Immunohistochemical studies in vivo and in vitro along with analysis of targeted mutants provide evidence that laminin-dependent aggregation of dystroglycan in the postsynaptic membrane is a key step in synaptic maturation. Another synaptically concentrated laminin receptor, Bcam, is dispensable. Together with previous studies implicating laminins as organizers of presynaptic differentiation, these results show that laminins coordinate post- with presynaptic maturation.

  19. Epigenetic remodelling and dysregulation of DLGAP4 is linked with early-onset cerebellar ataxia

    DEFF Research Database (Denmark)

    Minocherhomji, Sheroy; Hansen, Claus; Kim, Hyung-Goo

    2014-01-01

    expression of DLGAP4 mRNAs and non-coding RNAs in haploid cells having the translocation. Our results provide new mechanistic insight into the way a balanced chromosomal rearrangement associated with a neurodevelopmental disorder perturbs allele-specific epigenetic mechanisms at breakpoints leading......Genome instability, epigenetic remodelling and structural chromosomal rearrangements are hallmarks of cancer. However, the coordinated epigenetic effects of constitutional chromosomal rearrangements that disrupt genes associated with congenital neurodevelopmental diseases are poorly understood....... To understand the genetic-epigenetic interplay at breakpoints of chromosomal translocations disrupting CG-rich loci, we quantified epigenetic modifications at DLGAP4 (SAPAP4), a key post-synaptic density 95 (PSD95) associated gene, truncated by the chromosome translocation t(8;20)(p12;q11.23), co...

  20. Brain-derived neurotrophic factor rapidly enhances phosphorylation of the postsynaptic N-methyl-d-aspartate receptor subunit 1

    OpenAIRE

    Suen, Piin-Chau; Wu, Kuo; Levine, Eric S; Mount, Howard T. J.; Xu, Jia-Ling; LIN, SIANG-YO; Black, Ira B.

    1997-01-01

    Although neurotrophins have traditionally been regarded as neuronal survival factors, recent work has suggested a role for these factors in synaptic plasticity. In particular, brain-derived neurotrophic factor (BDNF) rapidly enhances synaptic transmission in hippocampal neurons through trkB receptor stimulation and postsynaptic phosphorylation mechanisms. Activation of trkB also modulates hippocampal long-term potentiation, in which postsynaptic N-methyl-d-aspartate glutamate receptors play a...

  1. ZiBuPiYin recipe protects db/db mice from diabetes-associated cognitive decline through improving multiple pathological changes.

    Directory of Open Access Journals (Sweden)

    Jing Chen

    Full Text Available Multiple organ systems, including the brain, which undergoes changes that may increase the risk of cognitive decline, are adversely affected by diabetes mellitus (DM. Here, we demonstrate that type 2 diabetes mellitus (T2DM db/db mice exhibited hippocampus-dependent memory impairment, which might associate with a reduction in dendritic spine density in the pyramidal neurons of brain, Aβ1-42 deposition in the prefrontal cortex (PFC and hippocampus, and a decreased expression of neurostructural proteins including microtubule-associated protein (MAP2, a marker of dendrites, and postsynaptic density 95 (PSD95, a marker of excitatory synapses. To investigate the effects of the ZiBuPiYin recipe (ZBPYR, a traditional Chinese medicine recipe, on diabetes-related cognitive decline (DACD, db/db mice received daily administration of ZBPYR over an experimental period of 6 weeks. We then confirmed that ZBPYR rescued learning and memory performance impairments, reversed dendritic spine loss, reduced Aβ1-42 deposition and restored the expression levels of MAP2 and PSD95. The present study also revealed that ZBPYR strengthened brain leptin and insulin signaling and inhibited GSK3β overactivity, which may be the potential mechanism or underlying targets of ZBPYR. These findings conclude that ZBPYR prevents DACD, most likely by improving dendritic spine density and attenuating brain leptin and insulin signaling pathway injury. Our findings provide further evidence for the effects of ZBPYR on DACD.

  2. Social defeat stress induces depression-like behavior and alters spine morphology in the hippocampus of adolescent male C57BL/6 mice

    Directory of Open Access Journals (Sweden)

    Sergio D. Iñiguez

    2016-12-01

    Hippocampi were then dissected and Western blots were conducted to quantify protein levels for various markers important for synaptic plasticity including protein kinase M zeta (PKMζ, protein kinase C zeta (PKCζ, the dopamine-1 (D1 receptor, tyrosine hydroxylase (TH, and the dopamine transporter (DAT. Furthermore, we examined the presence of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA-receptor subunit GluA2 as well as colocalization with the post-synaptic density 95 (PSD95 protein, within different spine subtypes (filopodia, stubby, long-thin, mushroom using an immunohistochemistry and Golgi-Cox staining technique. The results revealed that social defeat induced a depression-like behavioral profile, as inferred from decreased social interaction levels, increased immobility on the tail suspension test, and decreases in body weight. Whole hippocampal immunoblots revealed decreases in GluA2, with a concomitant increase in DAT and TH levels in the stressed group. Spine morphology analyses further showed that defeated mice displayed a significant decrease in stubby spines, and an increase in long-thin spines within the CA1 stratum radiatum. Further evaluation of GluA2/PSD95 containing-spines demonstrated a decrease of these markers within long-thin and mushroom spine types. Together, these results indicate that juvenile social stress induces GluA2- and dopamine-associated dysregulation in the hippocampus – a neurobiological mechanism potentially underlying the development of mood-related syndromes as a consequence of adolescent bullying.

  3. Principal cell spiking, postsynaptic excitation, and oxygen consumption in the rat cerebellar cortex

    DEFF Research Database (Denmark)

    Thomsen, Kirsten; Piilgaard, Henning; Gjedde, Albert

    2009-01-01

    One contention within the field of neuroimaging concerns the character of the depicted activity: Does it represent neuronal action potential generation (i.e., spiking) or postsynaptic excitation? This question is related to the metabolic costs of different aspects of neurosignaling. The cerebellar...... excitatory synaptic input. Subsequent inhibition of action potential propagation and neurotransmission by blocking voltage-gated Na+-channels eliminated the increases in CMRO2 due to PF stimulation and increased PC spiking, but left a large fraction of CMRO2, i.e., basal CMRO2, intact. In conclusion, whereas...

  4. Treadmill exercise improves motor and memory functions in cerebral palsy rats through activation of PI3K-Akt pathway.

    Science.gov (United States)

    Jung, Sun-Young; Kim, Dae-Young

    2017-04-01

    Cerebral palsy (CP) is a chronic disorder characterized by physical disability and disruption of brain function. We evaluated the effects of treadmill exercise on motor and memory functions in relation with phosphatidylinositol 3-kinase (PI3K)-Akt pathway using CP rat model. Rota-rod test, step-down avoidance task, 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry, and western blot for synapsin I, postsynaptic density-95 (PSD-95), PI3K, Akt, and glycogen synthase kinase-3β (GSK-3β) were performed. CP was induced by maternal lipopolysaccharide (LPS)-injection with sensorimotor restriction. Five weeks after birth, the rats in the exercise groups were made to run on the treadmill for 30 min per one day, 5 times a week, during 4 weeks. Motor and memory functions were impaired in the LPS-induced CP rats and tread-mill exercise increased motor and memory functions in the CP rats. Cell proliferation in the hippocampus was suppressed in the LPS-induced CP rats and treadmill exercise increased hippocampal cell proliferation in the CP rats. Expressions of synapsin I, PSD-95, phosphorylated (p)-PI3K, and p-Akt were decreased in the LPS-induced CP rats and treadmill exercise enhanced the expressions of synapsin I, PSD-95, p-PI3K, and p-Akt in the CP rats. GSK-3β expression was increased in the LPS-induced CP rats and treadmill exercise suppressed GSK-3β expression in the CP rats. The present results suggest that treadmill exercise might improve motor and memory functions through activation of PI3K-Akt pathway.

  5. Targeted gene transfer of different genes to presynaptic and postsynaptic neocortical neurons connected by a glutamatergic synapse.

    Science.gov (United States)

    Zhang, Guo-rong; Zhao, Hua; Cao, Haiyan; Li, Xu; Geller, Alfred I

    2012-09-14

    Genetic approaches to analyzing neuronal circuits and learning would benefit from a technology to first deliver a specific gene into presynaptic neurons, and then deliver a different gene into an identified subset of their postsynaptic neurons, connected by a specific synapse type. Here, we describe targeted gene transfer across a neocortical glutamatergic synapse, using as the model the projection from rat postrhinal to perirhinal cortex. The first gene transfer, into the presynaptic neurons in postrhinal cortex, used a virus vector and standard gene transfer procedures. The vector expresses an artificial peptide neurotransmitter containing a dense core vesicle targeting domain, a NMDA NR1 subunit binding domain (from a monoclonal antibody), and the His tag. Upon release, this peptide neurotransmitter binds to NMDA receptors on the postsynaptic neurons. Antibody-mediated targeted gene transfer to these postsynaptic neurons in perirhinal cortex used a His tag antibody, as the peptide neurotransmitter contains the His tag. Confocal microscopy showed that with untargeted gene transfer, ~3% of the transduced presynaptic axons were proximal to a transduced postsynaptic dendrite. In contrast, with targeted gene transfer, ≥ 20% of the presynaptic axons were proximal to a transduced postsynaptic dendrite. Targeting across other types of synapses might be obtained by modifying the artificial peptide neurotransmitter to contain a binding domain for a different neurotransmitter receptor. This technology may benefit elucidating how specific neurons and subcircuits contribute to circuit physiology, behavior, and learning. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Specific interaction of postsynaptic densities with membrane rafts isolated from synaptic plasma membranes.

    Science.gov (United States)

    Liu, Qian; Yao, Wei-Dong; Suzuki, Tatsuo

    2013-06-01

    Postsynaptic membrane rafts are believed to play important roles in synaptic signaling, plasticity, and maintenance. We recently demonstrated the presence, at the electron microscopic level, of complexes consisting of membrane rafts and postsynaptic densities (PSDs) in detergent-resistant membranes (DRMs) prepared from synaptic plasma membranes (SPMs) ( Suzuki et al., 2011 , J Neurochem, 119, 64-77). To further explore these complexes, here we investigated the nature of the binding between purified SPM-DRMs and PSDs in vitro. In binding experiments, we used SPM-DRMs prepared after treating SPMs with n-octyl-β-d-glucoside, because at concentrations of 1.0% or higher it completely separates SPM-DRMs and PSDs, providing substantially PSD-free unique SPM-DRMs as well as DRM-free PSDs. PSD binding to PSD-free DRMs was identified by mass spectrometry, Western blotting, and electron microscopy. PSD proteins were not incorporated into SPMs, and significantly less PSD proteins were incorporated into DRMs prepared from liver membranes, providing in vitro evidence that binding of PSDs to DRMs is specific and suggestion of the presence of specific interacting molecules. These specific interactions may have important roles in synaptic development, function, and plasticity in vivo. In addition, the binding system we developed may be a good tool to search for binding molecules and binding mechanisms between PSDs and rafts.

  7. The relative contribution of NMDARs to excitatory postsynaptic currents is controlled by Ca2+-induced inactivation.

    Directory of Open Access Journals (Sweden)

    Fliza eValiullina

    2016-01-01

    Full Text Available NMDA receptors (NMDARs are important mediators of excitatory synaptic transmission and plasticity. A hallmark of these channels is their high permeability to Ca2+. At the same time, they are themselves inhibited by the elevation of intracellular Ca2+ concentration. It is unclear however, whether the Ca2+ entry associated with single NMDAR mediated synaptic events is sufficient to self-inhibit their activation. Such auto-regulation would have important effects on the dynamics of synaptic excitation in several central networks. Therefore, we studied NMDAR-mediated synaptic currents in mouse hippocampal CA1 pyramidal neurons. Postsynaptic responses to subthreshold Schaffer collateral stimulation depended strongly on the absence or presence of intracellular Ca2+ buffers. Loading of pyramidal cells with exogenous Ca2+ buffers increased the amplitude and decay time of NMDAR mediated EPSCs (EPSP and prolonged the time window for action potential generation.Our data indicate that the Ca2+ influx mediated by unitary synaptic events is sufficient to produce detectable self-inhibition of NMDARs even at a physiological Mg2+ concentration. Therefore, the contribution of NMDARs to synaptic excitation is strongly controlled by both previous synaptic activity as well as by the Ca2+ buffer capacity of postsynaptic neurons.

  8. Reelin exerts structural, biochemical and transcriptional regulation over presynaptic and postsynaptic elements in the adult hippocampus

    Directory of Open Access Journals (Sweden)

    Carles eBosch

    2016-05-01

    Full Text Available Reelin regulates neuronal positioning and synaptogenesis in the developing brain, and adult brain plasticity. Here we used transgenic mice overexpressing Reelin (Reelin-OE mice to perform a comprehensive dissection of the effects of this protein on the structural and biochemical features of dendritic spines and axon terminals in the adult hippocampus. Electron microscopy (EM revealed both higher density of synapses and structural complexity of both pre- and postsynaptic elements in transgenic mice than in WT mice. Dendritic spines had larger spine apparatuses, which correlated with a redistribution of Synaptopodin. Most of the changes observed in Reelin-OE mice were reversible after blockade of transgene expression, thus supporting the specificity of the observed phenotypes. Western blot and transcriptional analyses did not show major changes in the expression of pre- or postsynaptic proteins, including SNARE proteins, glutamate receptors, and scaffolding and signaling proteins. However, EM immunogold assays revealed that the NMDA receptor subunits NR2a and NR2b, and p-Cofilin showed a redistribution from synaptic to extrasynaptic pools. Taken together with previous studies, the present results suggest that Reelin regulates the structural and biochemical properties of adult hippocampal synapses by increasing their density and morphological complexity and by modifying the distribution and trafficking of major glutamatergic components.

  9. Dbo/Henji Modulates Synaptic dPAK to Gate Glutamate Receptor Abundance and Postsynaptic Response.

    Directory of Open Access Journals (Sweden)

    Manyu Wang

    2016-10-01

    Full Text Available In response to environmental and physiological changes, the synapse manifests plasticity while simultaneously maintains homeostasis. Here, we analyzed mutant synapses of henji, also known as dbo, at the Drosophila neuromuscular junction (NMJ. In henji mutants, NMJ growth is defective with appearance of satellite boutons. Transmission electron microscopy analysis indicates that the synaptic membrane region is expanded. The postsynaptic density (PSD houses glutamate receptors GluRIIA and GluRIIB, which have distinct transmission properties. In henji mutants, GluRIIA abundance is upregulated but that of GluRIIB is not. Electrophysiological results also support a GluR compositional shift towards a higher IIA/IIB ratio at henji NMJs. Strikingly, dPAK, a positive regulator for GluRIIA synaptic localization, accumulates at the henji PSD. Reducing the dpak gene dosage suppresses satellite boutons and GluRIIA accumulation at henji NMJs. In addition, dPAK associated with Henji through the Kelch repeats which is the domain essential for Henji localization and function at postsynapses. We propose that Henji acts at postsynapses to restrict both presynaptic bouton growth and postsynaptic GluRIIA abundance by modulating dPAK.

  10. Mesdc2 plays a key role in cell-surface expression of Lrp4 and postsynaptic specialization in myotubes.

    Science.gov (United States)

    Hoshi, Taisuke; Tezuka, Tohru; Yokoyama, Kazumasa; Iemura, Shun-ichiro; Natsume, Tohru; Yamanashi, Yuji

    2013-11-29

    Low-density lipoprotein receptor-related protein 4 (Lrp4) is essential for pre- and post-synaptic specialization at the neuromuscular junction (NMJ), an indispensable synapse between a motor nerve and skeletal muscle. Muscle-specific receptor tyrosine kinase MuSK must form a complex with Lrp4 to organize postsynaptic specialization at NMJs. Here, we show that the chaperon Mesdc2 binds to the intracellular form of Lrp4 and promotes its glycosylation and cell-surface expression. Furthermore, knockdown of Mesdc2 suppresses cell-surface expression of Lrp4, activation of MuSK, and postsynaptic specialization in muscle cells. These results suggest that Mesdc2 plays an essential role in NMJ formation by promoting Lrp4 maturation. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  11. The backbone of the post-synaptic density originated in a unicellular ancestor of choanoflagellates and metazoans

    Directory of Open Access Journals (Sweden)

    Manuel Michaël

    2010-02-01

    Full Text Available Abstract Background Comparative genomics of the early diverging metazoan lineages and of their unicellular sister-groups opens new window to reconstructing the genetic changes which preceded or accompanied the evolution of multicellular body plans. A recent analysis found that the genome of the nerve-less sponges encodes the homologues of most vertebrate post-synaptic proteins. In vertebrate excitatory synapses, these proteins assemble to form the post-synaptic density, a complex molecular platform linking membrane receptors, components of their signalling pathways, and the cytoskeleton. Newly available genomes from Monosiga brevicollis (a member of Choanoflagellata, the closest unicellular relatives of animals and Trichoplax adhaerens (a member of Placozoa: besides sponges, the only nerve-less metazoans offer an opportunity to refine our understanding of post-synaptic protein evolution. Results Searches for orthologous proteins and reconstruction of gene gains/losses based on the taxon phylogeny indicate that post-synaptic proteins originated in two main steps. The backbone scaffold proteins (Shank, Homer, DLG and some of their partners were acquired in a unicellular ancestor of choanoflagellates and metazoans. A substantial additional set appeared in an exclusive ancestor of the Metazoa. The placozoan genome contains most post-synaptic genes but lacks some of them. Notably, the master-scaffold protein Shank might have been lost secondarily in the placozoan lineage. Conclusions The time of origination of most post-synaptic proteins was not concomitant with the acquisition of synapses or neural-like cells. The backbone of the scaffold emerged in a unicellular context and was probably not involved in cell-cell communication. Based on the reconstructed protein composition and potential interactions, its ancestral function could have been to link calcium signalling and cytoskeleton regulation. The complex later became integrated into the evolving

  12. AAV-Mediated Overexpression of Neuroserpin in the Hippocampus Decreases PSD-95 Expression but Does Not Affect Hippocampal-Dependent Learning and Memory: e91050

    National Research Council Canada - National Science Library

    Vicky W K Tsang; Deborah Young; Matthew J During; Nigel P Birch

    2014-01-01

    .... A FLAG-tagged neuroserpin construct was initially characterized by in vitro transcription/translation and transfection into HEK293 cells and shown to interact with tPA and be targeted to the secretory pathway...

  13. AAV-mediated overexpression of neuroserpin in the hippocampus decreases PSD-95 expression but does not affect hippocampal-dependent learning and memory

    National Research Council Canada - National Science Library

    Tsang, Vicky W K; Young, Deborah; During, Matthew J; Birch, Nigel P

    2014-01-01

    .... A FLAG-tagged neuroserpin construct was initially characterized by in vitro transcription/translation and transfection into HEK293 cells and shown to interact with tPA and be targeted to the secretory pathway...

  14. Effects of the dimeric PSD-95 inhibitor UCCB01-144 on functional recovery after fimbria-fornix transection in rats

    DEFF Research Database (Denmark)

    Sommer, Jens Bak; Bach, Anders; Rytter, Hana Malá

    2017-01-01

    . UCCB01-144 or saline was injected into the lateral tail vein of rats immediately after sham surgery or FF-transection, and effects on spatial delayed alternation in a T-maze were assessed over a 28-day period. Task acquisition was significantly impaired in FF-transected animals, but there were...

  15. Postsynaptic Signals Mediating Induction of Long-Term Synaptic Depression in the Entorhinal Cortex

    Directory of Open Access Journals (Sweden)

    Saïd Kourrich

    2008-01-01

    Full Text Available The entorhinal cortex receives a large projection from the piriform cortex, and synaptic plasticity in this pathway may affect olfactory processing. In vitro whole cell recordings have been used here to investigate postsynaptic signalling mechanisms that mediate the induction of long-term synaptic depression (LTD in layer II entorhinal cortex cells. To induce LTD, pairs of pulses, using a 30-millisecond interval, were delivered at 1 Hz for 15 minutes. Induction of LTD was blocked by the NMDA receptor antagonist APV and by the calcium chelator BAPTA, consistent with a requirement for calcium influx via NMDA receptors. Induction of LTD was blocked when the FK506 was included in the intracellular solution to block the phosphatase calcineurin. Okadaic acid, which blocks activation of protein phosphatases 1 and 2a, also prevented LTD. Activation of protein phosphatases following calcium influx therefore contributes to induction of LTD in layer II of the entorhinal cortex.

  16. Pre- and postsynaptic dopamine mechanisms after repeated nicotine: effects of adrenalectomy.

    Science.gov (United States)

    Molander, Anna; Söderpalm, Bo

    2003-11-14

    The reinforcing properties of nicotine may be related to its ability to release dopamine in the nucleus accumbens and to increase locomotor activity in experimental animals. Both these effects are sensitized following repeated drug exposure, a phenomenon that may underlie important aspects of addiction. Adrenal steroids may be involved both in positive reinforcement and in sensitization. Adrenalectomy hampers, e.g., the induction of locomotor sensitization to nicotine, and cross-sensitization between stress and psychostimulants may develop. Here, the effect of adrenalectomy on postsynaptic and presynaptic changes of the mesolimbic dopamine system in association with nicotine sensitization was examined. Adrenalectomy or sham-operated rats received daily nicotine (0.4 mg/kg s.c.) or vehicle for 15 days, after which the locomotor responses to nicotine (0.2 mg/kg s.c.) and the dopamine D1/D2 receptor agonist apomorphine (1.0 mg/kg s.c. or 100 microM in the nucleus accumbens by reversed microdialysis) were recorded. In addition, accumbal dopamine output was monitored by in vivo microdialysis after nicotine challenge. Sham/nicotine animals showed a sensitized locomotor response to systemic and local apomorphine compared to all other groups, including the adrenalectomized/nicotine group. Nicotine increased accumbal dopamine output in all animals. In contrast, nicotine induced a pronounced increase in locomotor activity in the sham/nicotine animals compared to the other vehicle group and the adrenalectomized animals. These results indicate that adrenal steroids are involved in the induction of the postsynaptic component of nicotine sensitization, whereas their involvement in tentative presynaptic changes remains unclear.

  17. Effect of zolpidem on miniature IPSCs and occupancy of postsynaptic GABAA receptors in central synapses.

    Science.gov (United States)

    Perrais, D; Ropert, N

    1999-01-15

    GABAA-mediated miniature IPSCs (mIPSCs) were recorded from layer V pyramidal neurons of the visual cortex using whole-cell patch-clamp recording in rat brain slices. At room temperature, the benzodiazepine site agonist zolpidem enhanced both the amplitude (to 138 +/- 26% of control value at 10 microM) and the duration (163 +/- 14%) of mIPSCs. The enhancement of mIPSC amplitude was not caused by an increase of the single-channel conductance of the postsynaptic receptors, as determined by peak-scaled non-stationary fluctuation analysis of mIPSCs. The effect of zolpidem on fast, synaptic-like (1 msec duration) applications of GABA to outside-out patches was also investigated. The EC50 for fast GABA applications was 310 microM. In patches, zolpidem enhanced the amplitude of currents elicited by subsaturating GABA applications (100-300 microM) but not by saturating applications (10 mM). The increase of mIPSC amplitude by zolpidem provides evidence that the GABAA receptors are not saturated during miniature synaptic transmission in the recorded cells. By comparing the facilitation induced by 1 microM zolpidem on outside-out patches and mIPSCs, we estimated the concentration of GABA seen by the postsynaptic GABAA receptors to be approximately 300 microM after single vesicle release. We have estimated a similar degree of receptor occupancy at room and physiological temperature. However, at 35 degreesC, zolpidem did not enhance the amplitude of mIPSCs or of subsaturating GABA applications on patches, implying that, in these neurons, zolpidem cannot be used to probe the degree of receptor occupancy at physiological temperature.

  18. Striatal fast-spiking interneurons: from firing patterns to postsynaptic impact

    Directory of Open Access Journals (Sweden)

    Andreas eKlaus

    2011-07-01

    Full Text Available In the striatal microcircuit, fast-spiking (FS interneurons have an important role in mediating inhibition onto neighboring medium spiny (MS projection neurons. In this study, we combined computational modeling with in vitro and in vivo electrophysiological measurements to investigate FS cells in terms of their discharge properties and their synaptic efficacies onto MS neurons. In vivo firing of striatal FS interneurons is characterized by a high firing variability. It is not known, however, if this variability results from the input that FS cells receive, or if it is promoted by the stuttering spike behavior of these neurons. Both our model and measurements in vitro show that FS neurons that exhibit random stuttering discharge in response to steady depolarization, do not show the typical stuttering behavior when they receive fluctuating input. Importantly, our model predicts that electrically coupled FS cells show substantial spike synchronization only when they are in the stuttering regime. Therefore, together with the lack of synchronized firing of striatal FS interneurons that has been reported in vivo, these results suggest that neighboring FS neurons are not in the stuttering regime simultaneously and that in vivo FS firing variability is more likely determined by the input fluctuations. Furthermore, the variability in FS firing is translated to variability in the postsynaptic amplitudes in MS neurons due to the strong synaptic depression of the FS-to-MS synapse. Our results support the idea that these synapses operate over a wide range from strongly depressed to almost fully recovered. The strong inhibitory effects that FS cells can impose on their postsynaptic targets, and the fact that the FS-to-MS synapse model showed substantial depression over extended periods of time might indicate the importance of cooperative effects of multiple presynaptic FS interneurons and the precise orchestration of their activity.

  19. Whereas Short-Term Facilitation Is Presynaptic, Intermediate-Term Facilitation Involves Both Presynaptic and Postsynaptic Protein Kinases and Protein Synthesis

    Science.gov (United States)

    Jin, Iksung; Kandel, Eric R.; Hawkins, Robert D.

    2011-01-01

    Whereas short-term plasticity involves covalent modifications that are generally restricted to either presynaptic or postsynaptic structures, long-term plasticity involves the growth of new synapses, which by its nature involves both pre- and postsynaptic alterations. In addition, an intermediate-term stage of plasticity has been identified that…

  20. Dopamine synapse is a neuroligin-2–mediated contact between dopaminergic presynaptic and GABAergic postsynaptic structures

    Science.gov (United States)

    Uchigashima, Motokazu; Ohtsuka, Toshihisa; Kobayashi, Kazuto; Watanabe, Masahiko

    2016-01-01

    Midbrain dopamine neurons project densely to the striatum and form so-called dopamine synapses on medium spiny neurons (MSNs), principal neurons in the striatum. Because dopamine receptors are widely expressed away from dopamine synapses, it remains unclear how dopamine synapses are involved in dopaminergic transmission. Here we demonstrate that dopamine synapses are contacts formed between dopaminergic presynaptic and GABAergic postsynaptic structures. The presynaptic structure expressed tyrosine hydroxylase, vesicular monoamine transporter-2, and plasmalemmal dopamine transporter, which are essential for dopamine synthesis, vesicular filling, and recycling, but was below the detection threshold for molecules involving GABA synthesis and vesicular filling or for GABA itself. In contrast, the postsynaptic structure of dopamine synapses expressed GABAergic molecules, including postsynaptic adhesion molecule neuroligin-2, postsynaptic scaffolding molecule gephyrin, and GABAA receptor α1, without any specific clustering of dopamine receptors. Of these, neuroligin-2 promoted presynaptic differentiation in axons of midbrain dopamine neurons and striatal GABAergic neurons in culture. After neuroligin-2 knockdown in the striatum, a significant decrease of dopamine synapses coupled with a reciprocal increase of GABAergic synapses was observed on MSN dendrites. This finding suggests that neuroligin-2 controls striatal synapse formation by giving competitive advantage to heterologous dopamine synapses over conventional GABAergic synapses. Considering that MSN dendrites are preferential targets of dopamine synapses and express high levels of dopamine receptors, dopamine synapse formation may serve to increase the specificity and potency of dopaminergic modulation of striatal outputs by anchoring dopamine release sites to dopamine-sensing targets. PMID:27035941

  1. Pre- and postsynaptic dopamine SPECT in the early phase of idiopathic parkinsonism: a population-based study

    Energy Technology Data Exchange (ETDEWEB)

    Jakobson, Mo Susanna; Riklund, Katrine [Umeaa University, Department of Radiation Sciences, Diagnostic Radiology, Umeaa (Sweden); Linder, Jan; Forsgren, Lars [Umeaa University, Department of Pharmacology and Clinical Neuroscience, Neurology, Umeaa (Sweden); Larsson, Anne; Johansson, Lennart [Umeaa University, Department of Radiation Sciences, Radiation Physics, Umeaa (Sweden)

    2010-11-15

    The aim of this study was to assess the diagnostic contribution of pre- and postsynaptic dopamine SPECT in drug-naive patients with early idiopathic parkinsonism and to investigate possible differences between idiopathic Parkinson's disease (PD) and atypical parkinsonian syndromes (APS) and possible differences in motor subtypes of parkinsonism. A group of 128 newly diagnosed idiopathic parkinsonian patients and 48 healthy controls was studied. Presynaptic baseline SPECT with {sup 123}I-FP-CIT was performed in all patients and in 120 patients also a baseline postsynaptic SPECT with {sup 123}I-IBZM. Clinical diagnoses were reassessed after 12 months. Presynaptic uptake in the putamen and caudate was significantly reduced in patients compared to controls. Presynaptic uptake ratios were not different between PD patients and patients with APS, and postsynaptic uptake in APS was not significantly reduced compared to PD or controls. In half of the APS patients both pre- and postsynaptic uptake ratios were reduced on the same side in the striatum. Impaired motor performance was associated with decreased presynaptic uptake in the putamen in PD. The postural instability and gait difficulty (PIGD) subtype of PD had lower presynaptic uptake ratios than patients with tremor-dominated (TD) symptoms. Not only presynaptic putamen uptake ratios, but also caudate ratios were reduced in a majority of the patients in our study. At baseline scan, i.e. in an early stage of the disease, the accuracy of excluding APS in the whole study population was 85% using a combination of pre- and postsynaptic SPECT. Already at baseline, lower presynaptic SPECT ratios were seen in PD with PIGD at onset compared to those with TD subtype. (orig.)

  2. Presynaptic and postsynaptic ion channel expression in vestibular nuclei neurons after unilateral vestibular deafferentation.

    Science.gov (United States)

    Shao, Mei; Popratiloff, Anastas; Hirsch, June C; Peusner, Kenna D

    2009-01-01

    Vestibular compensation refers to the recovery of function occurring after unilateral vestibular deafferentation, but some patients remain uncompensated. Similarly, more than half of the operated chickens compensate three days after unilateral vestibular ganglionectomy (UVG), but the rest remain uncompensated. This review focuses on the studies performed on the principal cells of the chick tangential nucleus after UVG. The tangential nucleus is a major avian vestibular nucleus whose principal cells are all second-order, vestibular reflex projection neurons participating in the vestibuloocular and vestibulocollic reflexes controlling posture, balance, and eye movements. Using whole-cell patch-clamp approach in brain slice preparations, spontaneous spike firing, ionic conductances, and spontaneous excitatory postsynaptic currents (sEPSCs) are recorded in principal cells from controls and operated chickens three days after UVG. In compensated chickens, the proportion of spontaneous spike firing principal cells and their spike discharge rate are symmetric on the lesion and intact sides, with the rates increased over controls. However, in the uncompensated chickens, the spike discharge rate increases on the lesion side, but not on the intact side, where only silent principal cells are recorded. In all the experimental groups, including controls, silent principal cells are distinguished from spontaneous spiking cells by smaller persistent sodium conductances and higher activation thresholds for the fast sodium channel. In addition, silent principal cells on the intact side of uncompensated chickens have larger dendrotoxin-sensitive potassium conductances, with a higher ratio of immunolabeling for surface/cytoplasmic expression of a dendrotoxin-sensitive, potassium channel subunit, Kv1.1. Finally, in compensated chickens, sEPSC frequency is symmetric bilaterally, but in uncompensated chickens sEPSC frequency increased only on the lesion side, where the expression of Kv1

  3. Somatodendritic and excitatory postsynaptic distribution of neuron-type dystrophin isoform, Dp40, in hippocampal neurons.

    Science.gov (United States)

    Fujimoto, Takahiro; Itoh, Kyoko; Yaoi, Takeshi; Fushiki, Shinji

    2014-09-12

    The Duchenne muscular dystrophy (DMD) gene produces multiple dystrophin (Dp) products due to the presence of several promoters. We previously reported the existence of a novel short isoform of Dp, Dp40, in adult mouse brain. However, the exact biochemical expression profile and cytological distribution of the Dp40 protein remain unknown. In this study, we generated a polyclonal antibody against the NH2-terminal region of the Dp40 and identified the expression profile of Dp40 in the mouse brain. Through an analysis using embryonic and postnatal mouse cerebrums, we found that Dp40 emerged from the early neonatal stages until adulthood, whereas Dp71, an another Dp short isoform, was highly detected in both prenatal and postnatal cerebrums. Intriguingly, relative expressions of Dp40 and Dp71 were prominent in cultured dissociated neurons and non-neuronal cells derived from mouse hippocampus, respectively. Furthermore, the immunocytological distribution of Dp40 was analyzed in dissociated cultured neurons, revealing that Dp40 is detected in the soma and its dendrites, but not in the axon. It is worthy to note that Dp40 is localized along the subplasmalemmal region of the dendritic shafts, as well as at excitatory postsynaptic sites. Thus, Dp40 was identified as a neuron-type Dp possibly involving dendritic and synaptic functions. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Differential pre- and postsynaptic effects of desipramine on cardiac sympathetic nerve terminals in RHF.

    Science.gov (United States)

    Liang, Chang-Seng; Himura, Yoshihiro; Kashiki, Michihiro; Stevens, Suzanne Y

    2002-11-01

    Right heart failure (RHF) is characterized by chamber-specific reductions of myocardial norepinephrine (NE) reuptake, beta-receptor density, and profiles of cardiac sympathetic nerve ending neurotransmitters. To study the functional linkage between NE uptake and the pre- and postsynaptic changes, we administered desipramine (225 mg/day), a NE uptake inhibitor, to dogs with RHF produced by tricuspid avulsion and progressive pulmonary constriction or sham-operated dogs for 6 wk. Animals receiving no desipramine were studied as controls. We measured myocardial NE uptake activity using [(3)H]NE, beta-receptor density by [(125)I]iodocyanopindolol, inotropic responses to dobutamine, and noradrenergic terminal neurotransmitter profiles by glyoxylic acid-induced histofluorescence for catecholamines, and immunocytochemical staining for tyrosine hydroxylase and neuropeptide Y. Desipramine decreased myocardial NE uptake activity and had no effect on the resting hemodynamics in both RHF and sham animals but decreased myocardial beta-adrenoceptor density and beta-adrenergic inotropic responses in both ventricles of the RHF animals. However, desipramine treatment prevented the reduction of sympathetic neurotransmitter profiles in the failing heart. Our results indicate that NE uptake inhibition facilitates the reduction of myocardial beta-adrenoceptor density and beta-adrenergic subsensitivity in RHF, probably by increasing interstitial NE concentrations, but protects the cardiac noradrenergic nerve endings from damage, probably via blockade of NE-derived neurotoxic metabolites into the nerve endings.

  5. Auditory Stimuli Coding by Postsynaptic Potential and Local Field Potential Features.

    Science.gov (United States)

    de Assis, Juliana M; Santos, Mikaelle O; de Assis, Francisco M

    2016-01-01

    The relation between physical stimuli and neurophysiological responses, such as action potentials (spikes) and Local Field Potentials (LFP), has recently been experimented in order to explain how neurons encode auditory information. However, none of these experiments presented analyses with postsynaptic potentials (PSPs). In the present study, we have estimated information values between auditory stimuli and amplitudes/latencies of PSPs and LFPs in anesthetized rats in vivo. To obtain these values, a new method of information estimation was used. This method produced more accurate estimates than those obtained by using the traditional binning method; a fact that was corroborated by simulated data. The traditional binning method could not certainly impart such accuracy even when adjusted by quadratic extrapolation. We found that the information obtained from LFP amplitude variation was significantly greater than the information obtained from PSP amplitude variation. This confirms the fact that LFP reflects the action of many PSPs. Results have shown that the auditory cortex codes more information of stimuli frequency with slow oscillations in groups of neurons than it does with slow oscillations in neurons separately.

  6. Auditory Stimuli Coding by Postsynaptic Potential and Local Field Potential Features.

    Directory of Open Access Journals (Sweden)

    Juliana M de Assis

    Full Text Available The relation between physical stimuli and neurophysiological responses, such as action potentials (spikes and Local Field Potentials (LFP, has recently been experimented in order to explain how neurons encode auditory information. However, none of these experiments presented analyses with postsynaptic potentials (PSPs. In the present study, we have estimated information values between auditory stimuli and amplitudes/latencies of PSPs and LFPs in anesthetized rats in vivo. To obtain these values, a new method of information estimation was used. This method produced more accurate estimates than those obtained by using the traditional binning method; a fact that was corroborated by simulated data. The traditional binning method could not certainly impart such accuracy even when adjusted by quadratic extrapolation. We found that the information obtained from LFP amplitude variation was significantly greater than the information obtained from PSP amplitude variation. This confirms the fact that LFP reflects the action of many PSPs. Results have shown that the auditory cortex codes more information of stimuli frequency with slow oscillations in groups of neurons than it does with slow oscillations in neurons separately.

  7. Fast kinetics of exocytosis revealed by simultaneous measurements of presynaptic capacitance and postsynaptic currents at a central synapse.

    Science.gov (United States)

    Sun, J Y; Wu, L G

    2001-04-01

    The rate of release from nerve terminals depends on both the number of release sites and the rate of release at each site. The latter remains largely unknown at central synapses. We addressed this issue by simultaneously measuring the nerve terminal membrane capacitance and the postsynaptic current at single calyceal synapses in rat brainstem. We found that a 10 ms presynaptic step depolarization depleted a releasable pool containing 3300-5200 vesicles. Released vesicles were endocytosed with a time constant of a few seconds to tens of seconds. Release of only one third of this pool saturated both postsynaptic AMPA and NMDA receptors. A release site can release more than three vesicles in 10 ms (>300 vesicles per second). We conclude that both a large number of release sites and a fast release rate at each site enable synapses to release at a high rate.

  8. Increased adult neurogenesis in mice with a permanent overexpression of the postsynaptic 5-HT1A receptor.

    Science.gov (United States)

    Noto, Bettina; Klempin, Friederike; Alenina, Natalia; Bader, Michael; Fink, Heidrun; Sander, Svenja E

    2016-10-28

    Depression is among the leading causes of disability and disease burden. Recent studies point to an involvement of altered serotonin1A receptor (5-HT1AR) -mediated adult neurogenesis in depression. However, the exact underlying mechanisms remain unclear, mainly due to the complexity of the serotonergic system with its various receptors and their locations. Mice with permanent overexpression of postsynaptic 5-HT1ARs (OE mice) represent a unique tool for investigating the involvement of postsynaptic 5-HT1ARs in this context. Correct 5-HT1AR coupling and functioning has been demonstrated earlier, indicating that more postsynaptic 5-HT1ARs can be activated in these mice. Initially we examined morphometric parameters of the dentate gyrus (DG) and the prefrontal cortex as they are involved in adult hippocampal neurogenesis and/or depression. The volume of the DG in OE mice was increased in comparison to wildtype controls. We therefore investigated parameters of adult neurogenesis by the bromodeoxyuridine method. Proliferation and survival of newborn cells in the DG of OE mice were significantly increased. Significant increases in survived neurons were only detected in the female but not in the male subgroup. Additional staining for early precursor cells (Sox2) and progenitor cells of the neuronal lineage (doublecortin) showed an increase in type-1/2a as well as in type-2b/3 cells in OE mice. Our study suggests a leading role of the postsynaptic 5-HT1AR in adult hippocampal neurogenesis and might open an important link to depression. Copyright © 2016 The Author(s). Published by Elsevier Ireland Ltd.. All rights reserved.

  9. Sevoflurane depresses glutamatergic neurotransmission to brainstem inspiratory premotor neurons but not postsynaptic receptor function in a decerebrate dog model.

    Science.gov (United States)

    Stucke, Astrid G; Zuperku, Edward J; Tonkovic-Capin, Viseslav; Krolo, Mirko; Hopp, Francis A; Kampine, John P; Stuth, Eckehard A E

    2005-07-01

    Inspiratory bulbospinal neurons in the caudal ventral medulla are premotor neurons that drive motoneurons, which innervate pump muscles such as the diaphragm and external intercostals. Excitatory drive to these neurons is mediated by N-methyl-d-aspartate (NMDA) receptors and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors and is modulated by an inhibitory gamma-aminobutyric acid type A (GABAA)ergic input. The authors investigated the effect of sevoflurane on these synaptic mechanisms in decerebrate dogs. Studies were performed in decerebrate, vagotomized, paralyzed, and mechanically ventilated dogs during hypercapnic hyperoxia. The effect of 1 minimum alveolar concentration sevoflurane on extracellularly recorded activity of single neurons was measured during localized picoejection of the GABAA receptor blocker bicuculline and the glutamate agonists AMPA and NMDA. Complete blockade of the GABAAergic mechanism by bicuculline allowed differentiation between the effects of sevoflurane on overall GABAAergic inhibition and on overall glutamatergic excitation. The neuronal responses to exogenous AMPA and NMDA were used to estimate the anesthetic effect on postsynaptic glutamatergic neurotransmission. One minimum alveolar concentration sevoflurane depressed the spontaneous activity of 23 inspiratory premotor neurons by (mean +/- SD) 30.0 +/- 21.0% (P < 0.001). Overall glutamatergic excitation was depressed 19.2 +/- 18.5% (P < 0.001), whereas overall GABAAergic inhibition was enhanced by 11.9 +/- 25.1% (P < 0.05). The postsynaptic responses to exogenous AMPA and NMDA did not change. One minimum alveolar concentration depressed the activity of inspiratory premotor neurons by a reduction of glutamatergic excitation and an increase in overall inhibition. The postsynaptic AMPA and NMDA receptor response was unchanged. These findings contrast with studies in inspiratory premotor neurons where halothane did not change overall inhibition but significantly

  10. How does transient signaling input affect the spike timing of postsynaptic neuron near the threshold regime: an analytical study.

    Science.gov (United States)

    Shomali, Safura Rashid; Ahmadabadi, Majid Nili; Shimazaki, Hideaki; Rasuli, Seyyed Nader

    2017-12-01

    The noisy threshold regime, where even a small set of presynaptic neurons can significantly affect postsynaptic spike-timing, is suggested as a key requisite for computation in neurons with high variability. It also has been proposed that signals under the noisy conditions are successfully transferred by a few strong synapses and/or by an assembly of nearly synchronous synaptic activities. We analytically investigate the impact of a transient signaling input on a leaky integrate-and-fire postsynaptic neuron that receives background noise near the threshold regime. The signaling input models a single strong synapse or a set of synchronous synapses, while the background noise represents a lot of weak synapses. We find an analytic solution that explains how the first-passage time (ISI) density is changed by transient signaling input. The analysis allows us to connect properties of the signaling input like spike timing and amplitude with postsynaptic first-passage time density in a noisy environment. Based on the analytic solution, we calculate the Fisher information with respect to the signaling input's amplitude. For a wide range of amplitudes, we observe a non-monotonic behavior for the Fisher information as a function of background noise. Moreover, Fisher information non-trivially depends on the signaling input's amplitude; changing the amplitude, we observe one maximum in the high level of the background noise. The single maximum splits into two maximums in the low noise regime. This finding demonstrates the benefit of the analytic solution in investigating signal transfer by neurons.

  11. Presynaptic and postsynaptic mechanisms of synaptic plasticity and metaplasticity during intermediate-term memory formation in Aplysia.

    Science.gov (United States)

    Antonov, Igor; Kandel, Eric R; Hawkins, Robert D

    2010-04-21

    Synaptic plasticity and learning involve different mechanisms depending on the following: (1) the stage of plasticity and (2) the history of plasticity, or metaplasticity. However, little is known about how these two factors are related. We have addressed that question by examining mechanisms of synaptic plasticity during short-term and intermediate-term behavioral sensitization and dishabituation in a semi-intact preparation of the Aplysia siphon-withdrawal reflex. Dishabituation differs from sensitization in that it is preceded by habituation, and is thus a paradigm for metaplasticity. We find that whereas facilitation during short-term sensitization by one tail shock involves presynaptic covalent modifications by protein kinase A (PKA) and CamKII, facilitation during intermediate-term sensitization by four shocks involves both presynaptic (PKA, CaMKII) and postsynaptic (Ca(2+), CaMKII) covalent modifications, as well as both presynaptic and postsynaptic protein synthesis. The facilitation also involves presynaptic spike broadening 2.5 min after either one or four shocks, but not at later times. Dishabituation by four shocks differs from sensitization in several ways. First, it does not involve PKA or CaMKII, but rather involves presynaptic PKC. In addition, unlike sensitization with the same shock, dishabituation by four shocks does not involve protein synthesis or presynaptic spike broadening, and it also does not involve postsynaptic Ca(2+). These results demonstrate that not only the mechanisms but also the site of plasticity depend on both the stage of plasticity and metaplasticity during memory formation.

  12. Pre- and post-synaptic sympathetic function in human hibernating myocardium

    Energy Technology Data Exchange (ETDEWEB)

    John, Anna S.; Pepper, John R.; Dreyfus, Gilles D.; Pennell, Dudley J. [Imperial College, Hammersmith Hospital, National Heart and Lung Institute, London (United Kingdom); Mongillo, Marco; Khan, Muhammad T. [Imperial College, Hammersmith Hospital, Medical Research Council Clinical Sciences Centre, London (United Kingdom); Depre, Christophe [University of Medicine and Dentistry New Jersey, Cardiovascular Research Institute, Department of Cell Biology and Molecular Medicine, New Jersey, NJ (United States); University of Medicine and Dentistry New Jersey, Cardiovascular Research Institute, Department of Medicine, New Jersey, NJ (United States); Rimoldi, Ornella E. [Imperial College, Hammersmith Hospital, National Heart and Lung Institute, London (United Kingdom); Imperial College, Hammersmith Hospital, Medical Research Council Clinical Sciences Centre, London (United Kingdom); New York Medical College, Cardiovascular Research Institute, Department of Medicine, Valhalla, NY (United States); Camici, Paolo G. [Imperial College, Hammersmith Hospital, National Heart and Lung Institute, London (United Kingdom); Imperial College, Hammersmith Hospital, Medical Research Council Clinical Sciences Centre, London (United Kingdom)

    2007-12-15

    Impaired pre-synaptic noradrenaline uptake-1 mechanism has been reported in a swine model of hibernating myocardium (HM). To ascertain whether adrenergic neuroeffector abnormalities are present in human HM, we combined functional measurements in vivo using cardiovascular magnetic resonance (CMR) and positron emission tomography (PET) to assess pre- and post-synaptic sympathetic function. Twelve patients with coronary artery disease and chronic left ventricular (LV) dysfunction underwent CMR at baseline and 6 months after bypass for assessment of regional and global LV function and identification of segments with reversible dysfunction. Before surgery, myocardial noradrenaline uptake-1 ([{sup 11}C]meta-hydroxy-ephedrine; HED) and {beta}-adrenoceptor ({beta}-AR) density ([{sup 11}C]CGP-12177) were measured with PET. Patient PET data were compared with those in 18 healthy controls. The volume of distribution (V{sub d}) of HED in HM (47.95{+-}28.05 ml/g) and infarcted myocardium (42.69{+-}25.76 ml/g) was significantly reduced compared with controls (66.09{+-}14.48 ml/g). The V{sub d} of HED in normal myocardium (49.93{+-}20.48 ml/g) of patients was also lower than that in controls and the difference was close to statistical significance (p=0.06). Myocardial {beta}-AR density was significantly lower in HM (5.49{+-}2.35 pmol/g), infarcted (4.82{+-}2.61 pmol/g) and normal (5.86{+-}1.81 pmol/g) segments of patients compared with healthy controls (8.61{+-}1.32 pmol/g). Noradrenaline uptake-1 mechanism and {beta}-AR density are reduced in the myocardium of patients with chronic LV dysfunction and evidence of HM. The increased sympathetic activity to the heart in these patients is a generalised rather than regional phenomenon which is likely to contribute to the remodelling process of the whole LV rather than playing a causative role in HM. (orig.)

  13. Nicotinic acetylcholine receptor and the structural basis of neuromuscular transmission: insights from Torpedo postsynaptic membranes.

    Science.gov (United States)

    Unwin, Nigel

    2013-11-01

    The nicotinic acetylcholine (ACh) receptor, at the neuromuscular junction, is a neurotransmitter-gated ion channel that has been fine-tuned through evolution to transduce a chemical signal into an electrical signal with maximum efficiency and speed. It is composed from three similar and two identical polypeptide chains, arranged in a ring around a narrow membrane pore. Central to the design of this assembly is a hydrophobic gate in the pore, more than 50 Å away from sites in the extracellular domain where ACh binds. Although the molecular properties of the receptor have been explored intensively over the last few decades, only recently have structures emerged revealing its complex architecture and illuminating how ACh entering the binding sites opens the distant gate. Postsynaptic membranes isolated from the (muscle-derived) electric organ of the Torpedo ray have underpinned most of the structural studies: the membranes form tubular vesicles having receptors arranged on a regular surface lattice, which can be imaged directly in frozen physiological solutions. Advances in electron crystallographic techniques have also been important, enabling analysis of the closed- and open-channel forms of the receptor in unreacted tubes or tubes reacted briefly with ACh. The structural differences between these two forms show that all five subunits participate in a concerted conformational change communicating the effect of ACh binding to the gate, but that three of them (αγ, β and δ) play a dominant role. Flexing of oppositely facing pore-lining α-helices is the principal motion determining the closed/open state of the gate. These results together with the findings of biochemical, biophysical and other structural studies allow an integrated description of the receptor and of its mode of action at the synapse.

  14. Postsynaptic Signal Transduction Models for Long-Term Potentiation and Depression

    Science.gov (United States)

    Manninen, Tiina; Hituri, Katri; Kotaleski, Jeanette Hellgren; Blackwell, Kim T.; Linne, Marja-Leena

    2010-01-01

    More than a hundred biochemical species, activated by neurotransmitters binding to transmembrane receptors, are important in long-term potentiation (LTP) and long-term depression (LTD). To investigate which species and interactions are critical for synaptic plasticity, many computational postsynaptic signal transduction models have been developed. The models range from simple models with a single reversible reaction to detailed models with several hundred kinetic reactions. In this study, more than a hundred models are reviewed, and their features are compared and contrasted so that similarities and differences are more readily apparent. The models are classified according to the type of synaptic plasticity that is modeled (LTP or LTD) and whether they include diffusion or electrophysiological phenomena. Other characteristics that discriminate the models include the phase of synaptic plasticity modeled (induction, expression, or maintenance) and the simulation method used (deterministic or stochastic). We find that models are becoming increasingly sophisticated, by including stochastic properties, integrating with electrophysiological properties of entire neurons, or incorporating diffusion of signaling molecules. Simpler models continue to be developed because they are computationally efficient and allow theoretical analysis. The more complex models permit investigation of mechanisms underlying specific properties and experimental verification of model predictions. Nonetheless, it is difficult to fully comprehend the evolution of these models because (1) several models are not described in detail in the publications, (2) only a few models are provided in existing model databases, and (3) comparison to previous models is lacking. We conclude that the value of these models for understanding molecular mechanisms of synaptic plasticity is increasing and will be enhanced further with more complete descriptions and sharing of the published models. PMID:21188161

  15. Postsynaptic signal transduction models for long-term potentiation and depression

    Directory of Open Access Journals (Sweden)

    Tiina Manninen

    2010-12-01

    Full Text Available More than a hundred biochemical species, activated by neurotransmitters binding to transmembrane receptors, are important in long-term potentiation and depression. To investigate which species and interactions are critical for synaptic plasticity, many computational postsynaptic signal transduction models have been developed. The models range from simple models with a single reversible reaction to detailed models with several hundred kinetic reactions. In this study, more than a hundred models are reviewed, and their features are compared and contrasted so that similarities and differences are more readily apparent. The models are classified according to the type of synaptic plasticity that is modeled (long-term potentiation or long-term depression and whether they include diffusion or electrophysiological phenomena. Other characteristics that discriminate the models include the phase of synaptic plasticity modeled (induction, expression, or maintenance and the simulation method used (deterministic or stochastic method. We find that models are becoming increasingly sophisticated, by including stochastic properties, integrating with electrophysiological properties of entire neurons, or incorporating diffusion of signaling molecules. Simpler models continue to be developed because they are computationally efficient and allow theoretical analysis. The more complex models permit investigation of mechanisms underlying specific properties and experimental verification of model predictions. Nonetheless, it is difficult to fully comprehend the evolution of these models because (1 several models are not described in detail in the publications, (2 only a few models are provided in existing model databases, and (3 comparison to previous models is lacking. We conclude that the value of these models for understanding molecular mechanisms of synaptic plasticity is increasing and will be enhanced further with more complete descriptions and sharing of the

  16. Somatodendritic and excitatory postsynaptic distribution of neuron-type dystrophin isoform, Dp40, in hippocampal neurons

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Takahiro; Itoh, Kyoko, E-mail: kxi14@koto.kpu-m.ac.jp; Yaoi, Takeshi; Fushiki, Shinji

    2014-09-12

    Highlights: • Identification of dystrophin (Dp) shortest isoform, Dp40, is a neuron-type Dp. • Dp40 expression is temporally and differentially regulated in comparison to Dp71. • Somatodendritic and nuclear localization of Dp40. • Dp40 is localized to excitatory postsynapses. • Dp40 might play roles in dendritic and synaptic functions. - Abstract: The Duchenne muscular dystrophy (DMD) gene produces multiple dystrophin (Dp) products due to the presence of several promoters. We previously reported the existence of a novel short isoform of Dp, Dp40, in adult mouse brain. However, the exact biochemical expression profile and cytological distribution of the Dp40 protein remain unknown. In this study, we generated a polyclonal antibody against the NH{sub 2}-terminal region of the Dp40 and identified the expression profile of Dp40 in the mouse brain. Through an analysis using embryonic and postnatal mouse cerebrums, we found that Dp40 emerged from the early neonatal stages until adulthood, whereas Dp71, an another Dp short isoform, was highly detected in both prenatal and postnatal cerebrums. Intriguingly, relative expressions of Dp40 and Dp71 were prominent in cultured dissociated neurons and non-neuronal cells derived from mouse hippocampus, respectively. Furthermore, the immunocytological distribution of Dp40 was analyzed in dissociated cultured neurons, revealing that Dp40 is detected in the soma and its dendrites, but not in the axon. It is worthy to note that Dp40 is localized along the subplasmalemmal region of the dendritic shafts, as well as at excitatory postsynaptic sites. Thus, Dp40 was identified as a neuron-type Dp possibly involving dendritic and synaptic functions.

  17. Photolysis of Postsynaptic Caged Ca2+ Can Potentiate and Depress Mossy Fiber Synaptic Responses in Rat Hippocampal CA3 Pyramidal Neurons

    Science.gov (United States)

    Wang, Jun; Yeckel, Mark F.; Johnston, Daniel; Zucker, Robert S.

    2010-01-01

    The induction of mossy fiber-CA3 long-term potentiation (LTP) and depression (LTD) has been variously described as being dependent on either pre- or postsynaptic factors. Some of the postsynaptic factors for LTP induction include ephrin-B receptor tyrosine kinases and a rise in postsynaptic Ca2+ ([Ca2+]i). Ca2+ is also believed to be involved in the induction of the various forms of LTD at this synapse. We used photolysis of caged Ca2+ compounds to test whether a postsynaptic rise in [Ca2+]i is sufficient to induce changes in synaptic transmission at mossy fiber synapses onto rat hippocampal CA3 pyramidal neurons. We were able to elevate postsynaptic [Ca2+]i to approximately 1 μm for a few seconds in pyramidal cell somata and dendrites. We estimate that CA3 pyramidal neurons have approximately fivefold greater endogenous Ca2+ buffer capacity than CA1 neurons, limiting the rise in [Ca2+]i achievable by photolysis. This [Ca2+]i rise induced either a potentiation or a depression at mossy fiber synapses in different preparations. Neither the potentiation nor the depression was accompanied by consistent changes in paired-pulse facilitation, suggesting that these forms of plasticity may be distinct from synaptically induced LTP and LTD at this synapse. Our results are consistent with a postsynaptic locus for the induction of at least some forms of synaptic plasticity at mossy fiber synapses. PMID:14645386

  18. Postsynaptic GABA(B Receptors Contribute to the Termination of Giant Depolarizing Potentials in CA3 Neonatal Rat Hippocampus

    Directory of Open Access Journals (Sweden)

    Ilgam Khalilov

    2017-06-01

    Full Text Available During development, hippocampal CA3 network generates recurrent population bursts, so-called Giant Depolarizing Potentials (GDPs. GDPs are characterized by synchronous depolarization and firing of CA3 pyramidal cells followed by afterhyperpolarization (GDP-AHP. Here, we explored the properties of GDP-AHP in CA3 pyramidal cells using gramicidin perforated patch clamp recordings from neonatal rat hippocampal slices. We found that GDP-AHP occurs independently of whether CA3 pyramidal cells fire action potentials (APs or remain silent during GDPs. However, the amplitude of GDP-AHP increased with the number of APs the cells fired during GDPs. The reversal potential of the GDP-AHP was close to the potassium equilibrium potential. During voltage-clamp recordings, current-voltage relationships of the postsynaptic currents activated during GDP-AHP were characterized by reversal near the potassium equilibrium potential and inward rectification, similar to the responses evoked by the GABA(B receptor agonists. Finally, the GABA(B receptor antagonist CGP55845 strongly reduced GDP-AHP and prolonged GDPs, eventually transforming them to the interictal and ictal-like discharges. Together, our findings suggest that the GDP-AHP involves two mechanisms: (i postsynaptic GABA(B receptor activated potassium currents, which are activated independently on whether the cell fires or not during GDPs; and (ii activity-dependent, likely calcium activated potassium currents, whose contribution to the GDP-AHP is dependent on the amount of firing during GDPs. We propose that these two complementary inhibitory postsynaptic mechanisms cooperate in the termination of GDP.

  19. Distinct Roles of Different Presynaptic and Postsynaptic NCAM Isoforms in Early Motoneuron-Myotube Interactions Required for Functional Synapse Formation.

    Science.gov (United States)

    Hata, Katsusuke; Maeno-Hikichi, Yuka; Yumoto, Norihiro; Burden, Steven J; Landmesser, Lynn T

    2018-01-10

    The neural cell adhesion molecule (NCAM) is expressed both presynaptically and postsynaptically during neuromuscular junction formation. Genetic deletion in mice of all three isoforms (180, 140, and 120 kDa), or just the 180 isoform, suggested that different isoforms played distinct roles in synaptic maturation. Here we characterized in mice of either sex the earliest adhesive contacts between the growth cones of motoneurons and myotubes and their subsequent maturation into functional synapses in cocultures of motoneurons and myotubes, which expressed their normal complement of NCAM isoforms, or were lacking all isoforms either presynaptically or postsynaptically. Growth cone contact with +/+ mouse myotubes resulted in immediate adhesive contacts and the rapid downregulation of growth cone motility. When contacting NCAM -/- myotubes, growth cones touched and retracted/collapsed multiple times and failed to form stable contacts, even after 10 h. Exogenous expression in myotubes of either the 180 or 140 isoform, but not the 120 kDa isoform, rescued the rapid formation of stable contacts, the accumulation of presynaptic and postsynaptic molecules, and functional transmission. When NCAM was absent only in motoneurons, growth cones did not retract upon myotube contact, but, since their motility was not downregulated, they grew off the ends of the myotubes, failing to form synapses. The agrin receptor Lrp4 was strongly downregulated in NCAM-negative myotubes, and motoneuron growth cones did not make stable contacts with Lrp4-negative myotubes. These studies have identified novel roles for presynaptic and postsynaptic NCAM in mediating early cell-cell interactions required for synapse formation. SIGNIFICANCE STATEMENT Although many molecular signals needed to form the functionally effective neuromuscular synapses required for normal movement have been described, the earliest signals that let motoneuron growth cones make stable adhesive contacts with myotubes and cease

  20. Elevated NMDA receptor levels and enhanced postsynaptic long-term potentiation induced by prenatal exposure to valproic acid

    DEFF Research Database (Denmark)

    Rinaldi, Tania; Kulangara, Karina; Antoniello, Katia

    2007-01-01

    as the commonly linked kinase calcium/calmodulin-dependent protein kinase II. Synaptic plasticity experiments between pairs of pyramidal neurons revealed an augmented postsynaptic form of long-term potentiation. These results indicate that VPA significantly enhances NMDA receptor-mediated transmission and causes...... increased plasticity in the neocortex. Enhanced plasticity introduces a surprising perspective to the potential molecular and synaptic mechanisms involved in children prenatally exposed to VPA.......Valproic acid (VPA) is a powerful teratogen causing birth defects in humans, including autism spectrum disorder (ASD), if exposure occurs during the first trimester of embryogenesis. Learning and memory alterations are common symptoms of ASD, but underlying molecular and synaptic alterations remain...

  1. Pre- and Postsynaptic Role of Dopamine D2 Receptor DD2R in Drosophila Olfactory Associative Learning

    Directory of Open Access Journals (Sweden)

    Cheng Qi

    2014-11-01

    Full Text Available Dopaminergic neurons in Drosophila play critical roles in diverse brain functions such as motor control, arousal, learning, and memory. Using genetic and behavioral approaches, it has been firmly established that proper dopamine signaling is required for olfactory classical conditioning (e.g., aversive and appetitive learning. Dopamine mediates its functions through interaction with its receptors. There are two different types of dopamine receptors in Drosophila: D1-like (dDA1, DAMB and D2-like receptors (DD2R. Currently, no study has attempted to characterize the role of DD2R in Drosophila learning and memory. Using a DD2R-RNAi transgenic line, we have examined the role of DD2R, expressed in dopamine neurons (i.e., the presynaptic DD2R autoreceptor, in larval olfactory learning. The function of postsynaptic DD2R expressed in mushroom body (MB was also studied as MB is the center for Drosophila learning, with a function analogous to that of the mammalian hippocampus. Our results showed that suppression of presynaptic DD2R autoreceptors impairs both appetitive and aversive learning. Similarly, postsynaptic DD2R in MB neurons appears to be involved in both appetitive and aversive learning. The data confirm, for the first time, that DD2R plays an important role in Drosophila olfactory learning.

  2. Correlative fluorescence and electron microscopy of biocytin-filled neurons with a preservation of the postsynaptic ultrastructure.

    Science.gov (United States)

    Morozov, Youri; Khalilov, Ilgam; Ben-Ari, Yehezkel; Represa, Alfonso

    2002-05-30

    Several techniques enable to inject intracellularly neurons with dyes and to use light and electron microscopy to correlate the physiological data with the morphological properties of the neuron. However, the ultrastructure of the neuron is usually obscured by the injected dye thus notably precluding the analysis of the postsynaptic specialisation and that of the other organelles. To overcome this problem, we have developed a technique based on fluorophore- and ultra small gold-conjugated streptavidins. We report, that this method facilitates the identification of intracellular organelles of the biocytin-filled neuron and of postsynaptic densities. This method is valid for the study of early postnatal neurons that are particularly refractory to this type of analysis. The procedure introduced here consists of the following steps: (1) injection of biocytin into the neuron by a patch-clamp pipette, (2) aldehyde fixation, (3) reaction with a fluorophore-conjugated streptavidin, (4) analysis with a fluorescence microscope, (5) formation of avidin-biotin complexes (ABC), (6) reaction with an ultra small gold-conjugated streptavidin, (7) silver enhancement of gold, (8) postfixation with osmium tetroxide and embedding in resin, (9) ultrathin sectioning and analysis with an electron microscope. Using this method, we show that in early postnatal hippocampal neurons, that have been injected with biocytine, it is possible to determine the morphology of the dendritic and axonal trees (including very thin details such as spines and filopodia) and to identify the localisation of the symmetric and asymmetric synapses on dendrites of the injected neuron.

  3. Developmental changes in membrane properties and postsynaptic currents of granule cells in rat dentate gyrus.

    Science.gov (United States)

    Liu, Y B; Lio, P A; Pasternak, J F; Trommer, B L

    1996-08-01

    1. Whole cell patch-clamp recordings were used to study dentate gyrus granule cells in hippocampal slices from juvenile rats (postnatal days 8-32). Membrane properties were measured with the use of current-clamp recordings and were correlated with the morphology of a subgroup of neurons filled with biocytin. The components of the postsynaptic currents (PSCs) induced by medial perforant path stimulation were characterized with the use of specific receptor antagonists in voltage-clamp recordings. 2. Granule cells located in the middle third of the superior blade of stratum granulosum from the rostral third of hippocampus were divided into three groups according to their input resistance (IR). Neurons with low IR (206 +/- 182 M omega, mean +/- SD) had hyperpolarized resting membrane potentials (-82 +/- 7 mV) and high-amplitude action potentials (108 +/- 23 mV). Neurons were high IR (1,259 +/- 204 M omega) had more depolarized resting membrane potentials (-54 +/- 6 mV) and lower-amplitude action potentials (71 +/- 10 mV). Neurons with intermediate IR (619 +/- 166 M omega) also had intermediate resting membrane potentials (-63 +/- 7 mV) and action potential amplitudes (86 +/- 14 mV). Low-IR neurons became increasingly prevalent with advancing postnatal age, but neurons from each group could be found throughout the entire period under study. 3. Morphological studies of low-IR neurons revealed an extensive dendritic arborization that traversed the entire molecular layer and was characteristic of mature granule cells. High-IR cells had smaller somata and short, simple dendritic arborization that incompletely penetrated the molecular layer and were classified as immature. Intermediate-IR cells had morphological features of intermediate maturity. 4. The initial phase of the PSC evoked at -80 mV was a fast inward current that was comparable with respect to latency to peak, latency to onset, and 10-90% rise time in neurons of all maturities held at -80 mV. This current was 6

  4. Differential response of hippocampal subregions to stress and learning.

    Directory of Open Access Journals (Sweden)

    Darby F Hawley

    Full Text Available The hippocampus has two functionally distinct subregions-the dorsal portion, primarily associated with spatial navigation, and the ventral portion, primarily associated with anxiety. In a prior study of chronic unpredictable stress (CUS in rodents, we found that it selectively enhanced cellular plasticity in the dorsal hippocampal subregion while negatively impacting it in the ventral. In the present study, we determined whether this adaptive plasticity in the dorsal subregion would confer CUS rats an advantage in a spatial task-the radial arm water maze (RAWM. RAWM exposure is both stressful and requires spatial navigation, and therefore places demands simultaneously upon both hippocampal subregions. Therefore, we used Western blotting to investigate differential expression of plasticity-associated proteins (brain derived neurotrophic factor [BDNF], proBDNF and postsynaptic density-95 [PSD-95] in the dorsal and ventral subregions following RAWM exposure. Lastly, we used unbiased stereology to compare the effects of CUS on proliferation, survival and neuronal differentiation of cells in the dorsal and ventral hippocampal subregions. We found that CUS and exposure to the RAWM both increased corticosterone, indicating that both are stressful; nevertheless, CUS animals had significantly better long-term spatial memory. We also observed a subregion-specific pattern of protein expression following RAWM, with proBDNF increased in the dorsal and decreased in the ventral subregion, while PSD-95 was selectively upregulated in the ventral. Finally, consistent with our previous study, we found that CUS most negatively affected neurogenesis in the ventral (compared to the dorsal subregion. Taken together, our data support a dual role for the hippocampus in stressful experiences, with the more resilient dorsal portion undergoing adaptive plasticity (perhaps to facilitate escape from or neutralization of the stressor, and the ventral portion involved in

  5. Long-term potentiation in hippocampal oriens interneurons: postsynaptic induction, presynaptic expression and evaluation of candidate retrograde factors

    Science.gov (United States)

    Nicholson, Elizabeth; Kullmann, Dimitri M.

    2014-01-01

    Several types of hippocampal interneurons exhibit a form of long-term potentiation (LTP) that depends on Ca2+-permeable AMPA receptors and group I metabotropic glutamate receptors. Several sources of evidence point to a presynaptic locus of LTP maintenance. The retrograde factor that triggers the expression of LTP remains unidentified. Here, we show that trains of action potentials in putative oriens-lacunosum-moleculare interneurons of the mouse CA1 region can induce long-lasting potentiation of stimulus-evoked excitatory postsynaptic currents that mimics LTP elicited by high-frequency afferent stimulation. We further report that blockers of nitric oxide production or TRPV1 receptors failed to prevent LTP induction. The present results add to the evidence that retrograde signalling underlies N-methyl-d-aspartate (NMDA) receptor-independent LTP in oriens interneurons, mediated by an unidentified factor. PMID:24298136

  6. Postsynaptic GABABRs Inhibit L-Type Calcium Channels and Abolish Long-Term Potentiation in Hippocampal Somatostatin Interneurons.

    Science.gov (United States)

    Booker, Sam A; Loreth, Desiree; Gee, Annabelle L; Watanabe, Masahiko; Kind, Peter C; Wyllie, David J A; Kulik, Ákos; Vida, Imre

    2018-01-02

    Inhibition provided by local GABAergic interneurons (INs) activates ionotropic GABAA and metabotropic GABAB receptors (GABABRs). Despite GABABRs representing a major source of inhibition, little is known of their function in distinct IN subtypes. Here, we show that, while the archetypal dendritic-inhibitory somatostatin-expressing INs (SOM-INs) possess high levels of GABABR on their somato-dendritic surface, they fail to produce significant postsynaptic inhibitory currents. Instead, GABABRs selectively inhibit dendritic CaV1.2 (L-type) Ca2+ channels on SOM-IN dendrites, leading to reduced calcium influx and loss of long-term potentiation at excitatory input synapses onto these INs. These data provide a mechanism by which GABABRs can contribute to disinhibition and control the efficacy of extrinsic inputs to hippocampal networks. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. A Mammalian Retinal Ganglion Cell Implements a Neuronal Computation That Maximizes the SNR of Its Postsynaptic Currents.

    Science.gov (United States)

    Homann, Jan; Freed, Michael A

    2017-02-08

    Neurons perform computations by integrating excitatory and inhibitory synaptic inputs. Yet, it is rarely understood what computation is being performed, or how much excitation or inhibition this computation requires. Here we present evidence for a neuronal computation that maximizes the signal-to-noise power ratio (SNR). We recorded from OFF delta retinal ganglion cells in the guinea pig retina and monitored synaptic currents that were evoked by visual stimulation (flashing dark spots). These synaptic currents were mediated by a decrease in an outward current from inhibitory synapses (disinhibition) combined with an increase in an inward current from excitatory synapses. We found that the SNR of combined excitatory and disinhibitory currents was voltage sensitive, peaking at membrane potentials near resting potential. At the membrane potential for maximal SNR, the amplitude of each current, either excitatory or disinhibitory, was proportional to its SNR. Such proportionate scaling is the theoretically best strategy for combining excitatory and disinhibitory currents to maximize the SNR of their combined current. Moreover, as spot size or contrast changed, the amplitudes of excitatory and disinhibitory currents also changed but remained in proportion to their SNRs, indicating a dynamic rebalancing of excitatory and inhibitory currents to maximize SNR.SIGNIFICANCE STATEMENT We present evidence that the balance of excitatory and disinhibitory inputs to a type of retinal ganglion cell maximizes the signal-to-noise ratio power ratio (SNR) of its postsynaptic currents. This is significant because chemical synapses on a retinal ganglion cell require the probabilistic release of transmitter. Consequently, when the same visual stimulus is presented repeatedly, postsynaptic currents vary in amplitude. Thus, maximizing SNR may be a strategy for producing the most reliable signal possible given the inherent unreliability of synaptic transmission. Copyright © 2017 the authors

  8. Neuropeptide Y inhibits hypocretin/orexin neurons by multiple presynaptic and postsynaptic mechanisms: tonic depression of the hypothalamic arousal system.

    Science.gov (United States)

    Fu, Li-Ying; Acuna-Goycolea, Claudio; van den Pol, Anthony N

    2004-10-06

    Neurons that release neuropeptide Y (NPY) have important effects on hypothalamic homeostatic regulation, including energy homeostasis, and innervate hypocretin neurons. Using whole-cell patch-clamp recording, we explored NPY actions on hypocretin cells identified by selective green fluorescent protein expression in mouse hypothalamic slices. NPY reduced spike frequency and hyperpolarized the membrane potential of hypocretin neurons. The NPY hyperpolarizing action persisted in tetrodotoxin (TTX), was mimicked by Y1 receptor-selective agonists [Pro34]-NPY and [D-Arg25]-NPY, and was abolished by the Y1-specific antagonist BIBP3226 [(R)-N2-(diphenylacetyl)-N-[(4-hydroxyphenyl)methyl]-D-arginine-amide], consistent with a direct activation of postsynaptic Y1 receptors. NPY induced a current that was dependent on extracellular potassium, reversed near the potassium equilibrium potential, showed inward rectification, was blocked by extracellular barium, and was abolished by GDP-betaS in the recording pipette, consistent with a G-protein-activated inwardly rectifying K+ (GIRK) current. [Pro34]-NPY evoked, and BIBP3226 blocked, the activation of the GIRK-type current, indicating mediation by a Y1 receptor. NPY attenuated voltage-dependent calcium currents mainly via a Y1 receptor subtype. BIBP3226 increased spontaneous spike frequency, suggesting an ongoing Y1 receptor-mediated NPY inhibition. In TTX, miniature EPSCs were reduced in frequency but not amplitude by NPY, NPY13-36, and [D-Trp32]-NPY, but not by [Pro34]-NPY, suggesting the presynaptic inhibition was mediated by a Y2/Y5 receptor. NPY had little effect on GABA-mediated miniature IPSCs but depressed spontaneous IPSCs. Together, these data support the view that NPY reduces the activity of hypocretin neurons by multiple presynaptic and postsynaptic mechanisms and suggest NPY axons innervating hypocretin neurons may tonically attenuate hypocretin-regulated arousal.

  9. Interplay between presynaptic and postsynaptic activities is required for dendritic plasticity and synaptogenesis in the supraoptic nucleus.

    Science.gov (United States)

    Chevaleyre, Vivien; Moos, Francoise C; Desarménien, Michel G

    2002-01-01

    Developing oxytocin and vasopressin (OT/AVP) supraoptic nucleus (SON) neurons positively autocontrol their electrical activity via dendritic release of their respective peptide. The effects of this autocontrol are maximum during the second postnatal week (PW2), when the dendritic arbor transiently increases and glutamatergic postsynaptic potentials appear. Here, we studied the role and interaction of dendritic OT/AVP release and glutamate release in dendritic plasticity and synaptogenesis in SON. In vivo treatment with the peptides antagonists or with an NMDA antagonist suppressed the transient increase in dendritic arbor of SON neurons at the beginning of PW2. Incubation of acute slices with these compounds decreased the dendritic arbor on a short time scale (3-8 hr) in slices of postnatal day 7 (P7) to P9 rats. Conversely, application of OT/AVP or NMDA increased dendritic branches in slices of P3-P6 rats. Their effects were inhibited by blockade of electrical activity, voltage-gated Ca2+ channels, or intracellular Ca2+ mobilization. They were also interdependent because both OT/AVP and NMDA (but not AMPA) receptor activation were required for increasing the dendritic arbor. Part of this interdependence probably results from a retrograde action of the peptides facilitating glutamate release. Finally, blocking OT/AVP receptors by in vivo treatment with the peptides antagonists during development decreased spontaneous glutamatergic synaptic activity recorded in young adults. These results show that an interplay between postsynaptic dendritic peptide release and presynaptic glutamate release is involved in the transient increase in dendritic arbor of SON neurons and indicate that OT/AVP are required for normal synaptogenesis of glutamatergic inputs in SON.

  10. Human Freud-2/CC2D1B: a novel repressor of postsynaptic serotonin-1A receptor expression.

    Science.gov (United States)

    Hadjighassem, Mahmoud R; Austin, Mark C; Szewczyk, Bernadeta; Daigle, Mireille; Stockmeier, Craig A; Albert, Paul R

    2009-08-01

    Altered expression of serotonin-1A (5-HT1A) receptors, both presynaptic in the raphe nuclei and post-synaptic in limbic and cortical target areas, has been implicated in mood disorders such as major depression and anxiety. Within the 5-HT1A receptor gene, a powerful dual repressor element (DRE) is regulated by two protein complexes: Freud-1/CC2D1A and a second, unknown repressor. Here we identify human Freud-2/CC2D1B, a Freud-1 homologue, as the second repressor. Freud-2 distribution was examined with Northern and Western blot, reverse transcriptase polymerase chain reaction, and immunohistochemistry/immunofluorescence; Freud-2 function was examined by electrophoretic mobility shift, reporter assay, and Western blot. Freud-2 RNA was widely distributed in brain and peripheral tissues. Freud-2 protein was enriched in the nuclear fraction of human prefrontal cortex and hippocampus but was weakly expressed in the dorsal raphe nucleus. Freud-2 immunostaining was co-localized with 5-HT1A receptors, neuronal and glial markers. In prefrontal cortex, Freud-2 was expressed at similar levels in control and depressed male subjects. Recombinant hFreud-2 protein bound specifically to 5' or 3' human DRE adjacent to the Freud-1 site. Human Freud-2 showed strong repressor activity at the human 5-HT1A or heterologous promoter in human HEK-293 5-HT1A-negative cells and neuronal SK-N-SH cells, a model of postsynaptic 5-HT1A receptor-positive cells. Furthermore, small interfering RNA knockdown of endogenous hFreud-2 expression de-repressed 5-HT1A promoter activity and increased levels of 5-HT1A receptor protein in SK-N-SH cells. Human Freud-2 binds to the 5-HT1A DRE and represses the human 5-HT1A receptor gene to regulate its expression in non-serotonergic cells and neurons.

  11. The Role of Hippocampal Structural Synaptic Plasticity in Repetitive Transcranial Magnetic Stimulation to Improve Cognitive Function in Male SAMP8 Mice

    Directory of Open Access Journals (Sweden)

    Jiang Ma

    2017-01-01

    Full Text Available Background: Repetitive transcranial magnetic stimulation (rTMS has been used to improve cognitive function, but the stimulation protocols are variable and the underlying mechanism is unclear. Therefore, we intend to examine whether 5Hz rTMS with 30% maximum output could improve cognitive functions in senescence-accelerated-prone mouse 8 (SAMP8 through changing synaptic plasticity. Methods: SAMP8 and senescence-accelerated-prone mouse/resistant 1 (SAMR1 (7-month old male were randomly divided into 3 groups: SMAP8 rTMS group (P8-rTMS, SMAP8 sham-rTMS group (P8-sham, and SAMR1 sham-rTMS group (R1-sham. The P8-rTMS group was treated daily with 5Hz rTMS with 30% maximum output for 14 consecutive days, whereas the other two groups were controls without rTMS stimulation. Morris water maze (MWM experiment was performed after rTMS or sham treatment to assess the effect of rTMS on cognitive function. Reverse transcription polymerase chain reaction and Western blot assays were used to detect the mRNA and protein expression of presynaptic Synapsin (SYN and postsynaptic density 95 (PSD95 in the hippocampus of these mice. Results: The mean escape latency of the P8-rTMS group was significantly shorter than that of the P8-sham group. The number of platform crossings of the P8-rTMS group was significantly higher than that of the P8-sham group. rTMS significantly upregulated the protein and mRNA expression of SYN and PSD95 in the hippocampus of p8-rTMS mice compared to those of P8 sham mice. Conclusion: 5Hz rTMS with 30% maximum output enhances learning and memory in the SAMP8 mice. This improvement may be associated with the increased expression of synaptic structure proteins SYN and PSD95 in the hippocampus.

  12. The Extracellular and Cytoplasmic Domains of Syndecan Cooperate Postsynaptically to Promote Synapse Growth at the Drosophila Neuromuscular Junction.

    Science.gov (United States)

    Nguyen, Margaret U; Kwong, Jereen; Chang, Julia; Gillet, Victoria G; Lee, Rachel M; Johnson, Karl Gregory

    2016-01-01

    The heparan sulfate proteoglycan (HSPG) Syndecan (Sdc) is a crucial regulator of synapse development and growth in both vertebrates and invertebrates. In Drosophila, Sdc binds via its extracellular heparan sulfate (HS) sidechains to the receptor protein tyrosine phosphatase LAR to promote the morphological growth of the neuromuscular junction (NMJ). To date, however, little else is known about the molecular mechanisms by which Sdc functions to promote synapse growth. Here we show that all detectable Sdc found at the NMJ is provided by the muscle, strongly suggesting a post-synaptic role for Sdc. We also show that both the cytoplasmic and extracellular domains of Sdc are required to promote synapse growth or to rescue Sdc loss of function. We report the results of a yeast two-hybrid screen using the cytoplasmic domains of Sdc as bait, and identify several novel candidate binding partners for the cytoplasmic domains of Sdc. Together, these studies provide new insight into the mechanism of Sdc function at the NMJ, and provide enticing future directions for further exploring how Sdc promotes synapse growth.

  13. The Extracellular and Cytoplasmic Domains of Syndecan Cooperate Postsynaptically to Promote Synapse Growth at the Drosophila Neuromuscular Junction.

    Directory of Open Access Journals (Sweden)

    Margaret U Nguyen

    Full Text Available The heparan sulfate proteoglycan (HSPG Syndecan (Sdc is a crucial regulator of synapse development and growth in both vertebrates and invertebrates. In Drosophila, Sdc binds via its extracellular heparan sulfate (HS sidechains to the receptor protein tyrosine phosphatase LAR to promote the morphological growth of the neuromuscular junction (NMJ. To date, however, little else is known about the molecular mechanisms by which Sdc functions to promote synapse growth. Here we show that all detectable Sdc found at the NMJ is provided by the muscle, strongly suggesting a post-synaptic role for Sdc. We also show that both the cytoplasmic and extracellular domains of Sdc are required to promote synapse growth or to rescue Sdc loss of function. We report the results of a yeast two-hybrid screen using the cytoplasmic domains of Sdc as bait, and identify several novel candidate binding partners for the cytoplasmic domains of Sdc. Together, these studies provide new insight into the mechanism of Sdc function at the NMJ, and provide enticing future directions for further exploring how Sdc promotes synapse growth.

  14. Sex Differences in Autism-Like Behavioral Phenotypes and Postsynaptic Receptors Expression in the Prefrontal Cortex of TERT Transgenic Mice.

    Science.gov (United States)

    Kim, Ki Chan; Cho, Kyu Suk; Yang, Sung Min; Gonzales, Edson Luck; Valencia, Schley; Eun, Pyeong Hwa; Choi, Chang Soon; Mabunga, Darine Froy; Kim, Ji-Woon; Noh, Judy Kyoungju; Kim, Hee Jin; Jeon, Se Jin; Han, Seol-Heui; Bahn, Geon Ho; Shin, Chan Young

    2017-07-01

    Autism spectrum disorder (ASD) remains unexplained and untreated despite the high attention of research in recent years. Aside from its various characteristics is the baffling male preponderance over the female population. Using a validated animal model of ASD which is the telomerase reverse transcriptase overexpressing mice (TERT-tg), we conducted ASD-related behavioral assessments and protein expression experiments to mark the difference between male and females of this animal model. After statistically analyzing the results, we found significant effects of TERT overexpression in sociability, social novelty preference, anxiety, nest building, and electroseizure threshold in the males but not their female littermates. Along these differences are the male-specific increased expressions of postsynaptic proteins which are the NMDA and AMPA receptors in the prefrontal cortex. The vGluT1 presynaptic proteins, but not GAD, were upregulated in both sexes of TERT-tg mice, although it is more significantly pronounced in the male group. Here, we confirmed that the behavioral effect of TERT overexpression in mice was male-specific, suggesting that the aberration of this gene and its downstream pathways preferentially affect the functional development of the male brain, consistent with the male preponderance in ASD.

  15. Betahistine produces post-synaptic inhibition of the excitability of the primary afferent neurons in the vestibular endorgans.

    Science.gov (United States)

    Soto, E; Chávez, H; Valli, P; Benvenuti, C; Vega, R

    2001-01-01

    Betahistine has been used to treat several vestibular disorders of both central and peripheral origin. The objective of this work was to study the action of betahistine in the vestibular endorgans. Experiments were done in wild larval axolotl (Ambystoma tigrinum). Multiunit extracellular recordings were obtained from the semicircular canal nerve using a suction electrode. Betahistine (10 microM to 10 mM; n = 32) inhibited the basal spike discharge of the vestibular afferent neurons with an IC50 of 600 microM. To define the site of action of betahistine, its interactions with the nitric oxide synthase inhibitor NG-nitro-L-arginine (3 microM) and with the cholinergic antagonists atropine (10 microM; n = 3) and d-tubocurarine (10 microM; n = 3) were studied. The action of betahistine when co-administered with these drugs was the same as that in control experiments, indicating that its effects did not include nitric oxide production or the activation of cholinergic receptors. In contrast, 0.01-1 mM betahistine reduced the excitatory action of kainic acid (10 microM; n = 6) and quiscualic acid (1 microM; n = 13). These results indicate that the action of betahistine on the spike discharge of afferent neurons seems to be due to a post-synaptic inhibitory action on the primary afferent neuron response to the hair cell neurotransmitter.

  16. Reduction in size of perforated postsynaptic densities in hippocampal axospinous synapses and age-related spatial learning impairments.

    Science.gov (United States)

    Nicholson, Daniel A; Yoshida, Rie; Berry, Robert W; Gallagher, Michela; Geinisman, Yuri

    2004-09-01

    A central problem in the neurobiology of normal aging is why learning is preserved in some aged individuals yet impaired in others. To investigate this issue, we examined whether age-related deficits in spatial learning are associated with a reduction in postsynaptic density (PSD) area in hippocampal excitatory synapses (i.e., with a structural modification that is likely to have a deleterious effect on synaptic function). A hippocampus-dependent version of the Morris water maze task was used to separate Long-Evans male rats into young adult, aged learning-unimpaired, and equally aged learning-impaired groups. Axospinous synapses from the CA1 stratum radiatum were analyzed using systematic random sampling and serial section analyses. We report that aged learning-impaired rats exhibit a marked ( approximately 30%) and significant reduction in PSD area, whereas aged learning-unimpaired rats do not. The observed structural alteration involves a substantial proportion of perforated synapses but is not observed in nonperforated synapses. These findings support the notion that many hippocampal perforated synapses become less efficient in aged learning-impaired rats, which may contribute to cognitive decline during normal aging.

  17. The post-synaptic density of human postmortem brain tissues: an experimental study paradigm for neuropsychiatric illnesses.

    Directory of Open Access Journals (Sweden)

    Chang-Gyu Hahn

    Full Text Available Recent molecular genetics studies have suggested various trans-synaptic processes for pathophysiologic mechanisms of neuropsychiatric illnesses. Examination of pre- and post-synaptic scaffolds in the brains of patients would greatly aid further investigation, yet such an approach in human postmortem tissue has yet to be tested. We have examined three methods using density gradient based purification of synaptosomes followed by detergent extraction (Method 1 and the pH based differential extraction of synaptic membranes (Methods 2 and 3. All three methods separated fractions from human postmortem brains that were highly enriched in typical PSD proteins, almost to the exclusion of pre-synaptic proteins. We examined these fractions using electron microscopy (EM and verified the integrity of the synaptic membrane and PSD fractions derived from human postmortem brain tissues. We analyzed protein composition of the PSD fractions using two dimensional liquid chromatography tandem mass spectrometry (2D LC-MS/MS and observed known PSD proteins by mass spectrometry. Immunoprecipitation and immunoblot studies revealed that expected protein-protein interactions and certain posttranscriptional modulations were maintained in PSD fractions. Our results demonstrate that PSD fractions can be isolated from human postmortem brain tissues with a reasonable degree of integrity. This approach may foster novel postmortem brain research paradigms in which the stoichiometry and protein composition of specific microdomains are examined.

  18. Postsynaptic and differential localization to neuronal subtypes of protocadherin beta16 in the mammalian central nervous system.

    Science.gov (United States)

    Junghans, Dirk; Heidenreich, Matthias; Hack, Iris; Taylor, Verdon; Frotscher, Michael; Kemler, Rolf

    2008-02-01

    The formation of synapses is dependent on the expression of surface adhesion molecules that facilitate correct recognition, stabilization and function. The more than 60 clustered protocadherins (Pcdhalpha, Pcdhbeta and Pcdhgamma) identified in human and mouse have attracted considerable attention because of their clustered genomic organization and the potential role of alpha- and gamma-Pcdhs in allocating a neuronal surface code specifying synaptic connectivity. Here, we investigated whether beta-Pcdhs also contribute to these processes. By performing RT-PCR, we found a striking parallel onset of expression of many beta-Pcdhs around the onset of neurogenesis and wide expression in the central nervous system. We generated antibodies specific to Pcdhb16 and showed localization of Pcdhb16 protein in the adult mouse cerebellum, hippocampus and cerebral cortex. Analysing the mouse retina in detail revealed localization of Pcdhb16 to specific cell types and, importantly, subsets of synapses. We show that Pcdhb16 localizes predominantly to postsynaptic compartments and the comparison with Pcdhb22 implies differential localization and functions of individual beta-Pcdhs in the mammalian central nervous system. Moreover, we provide evidence for a role of beta-Pcdhs in the outer segments and connecting cilia of photoreceptors. Our data show for the first time that beta-Pcdhs also localize to specific neuronal subpopulations and synapses, providing support for the hypothesis that clustered Pcdhs are candidate genes for the specification of synaptic connectivity and neuronal networks.

  19. Isolation and Pharmacological Characterization of α-Elapitoxin-Ot1a, a Short-Chain Postsynaptic Neurotoxin from the Venom of the Western Desert Taipan, Oxyuranus temporalis

    Directory of Open Access Journals (Sweden)

    Carmel M. Barber

    2016-02-01

    Full Text Available Taipans (Oxyuranus spp. are elapids with highly potent venoms containing presynaptic (β and postsynaptic (α neurotoxins. O. temporalis (Western Desert taipan, a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components have been isolated from this venom. We describe the characterization of α-elapitoxin-Ot1a (α-EPTX-Ot1a; 6712 Da, a short-chain postsynaptic neurotoxin, which accounts for approximately 30% of O. temporalis venom. α-Elapitoxin-Ot1a (0.1–1 µM produced concentration-dependent inhibition of indirect-twitches, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The inhibition of indirect twitches by α-elapitoxin-Ot1a (1 µM was not reversed by washing the tissue. Prior addition of taipan antivenom (10 U/mL delayed the neurotoxic effects of α-elapitoxin-Ot1a (1 µM and markedly attenuated the neurotoxic effects of α-elapitoxin-Ot1a (0.1 µM. α-Elapitoxin-Ot1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA2 value of 8.02 ± 0.05. De novo sequencing revealed the main sequence of the short-chain postsynaptic neurotoxin (i.e., α-elapitoxin-Ot1a as well as three other isoforms found in O. temporalis venom. α-Elapitoxin-Ot1a shows high sequence similarity (i.e., >87% with other taipan short-chain postsynaptic neurotoxins.

  20. Isolation and Pharmacological Characterization of α-Elapitoxin-Ot1a, a Short-Chain Postsynaptic Neurotoxin from the Venom of the Western Desert Taipan, Oxyuranus temporalis.

    Science.gov (United States)

    Barber, Carmel M; Rusmili, Muhamad Rusdi Ahmad; Hodgson, Wayne C

    2016-02-29

    Taipans (Oxyuranus spp.) are elapids with highly potent venoms containing presynaptic (β) and postsynaptic (α) neurotoxins. O. temporalis (Western Desert taipan), a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components have been isolated from this venom. We describe the characterization of α-elapitoxin-Ot1a (α-EPTX-Ot1a; 6712 Da), a short-chain postsynaptic neurotoxin, which accounts for approximately 30% of O. temporalis venom. α-Elapitoxin-Ot1a (0.1-1 µM) produced concentration-dependent inhibition of indirect-twitches, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The inhibition of indirect twitches by α-elapitoxin-Ot1a (1 µM) was not reversed by washing the tissue. Prior addition of taipan antivenom (10 U/mL) delayed the neurotoxic effects of α-elapitoxin-Ot1a (1 µM) and markedly attenuated the neurotoxic effects of α-elapitoxin-Ot1a (0.1 µM). α-Elapitoxin-Ot1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA₂ value of 8.02 ± 0.05. De novo sequencing revealed the main sequence of the short-chain postsynaptic neurotoxin (i.e., α-elapitoxin-Ot1a) as well as three other isoforms found in O. temporalis venom. α-Elapitoxin-Ot1a shows high sequence similarity (i.e., >87%) with other taipan short-chain postsynaptic neurotoxins.

  1. Postsynaptic pyramidal target selection by descending layer III pyramidal axons: dual intracellular recordings and biocytin filling in slices of rat neocortex.

    Science.gov (United States)

    Thomson, A M; Bannister, A P

    1998-06-01

    Paired intracellular recordings in slices of adult rat neocortex with biocytin filling of synaptically connected neurons were used to investigate the pyramidal targets, in layer V, of layer III pyramidal axons. The time-course and sensitivity of excitatory postsynaptic potentials to current injected at the soma, and locations of close appositions between presynaptic axons and postsynaptic dendrites, indicated that the majority of contributory synapses were located in layer V. Within a "column" of tissue, radius < or = 250 microm, the probability that a randomly selected layer III pyramid innervated a layer V pyramid was 1 in 4 if the target cell was a burst firing pyramid with an apical dendritic tuft in layers II/I. If, however, the potential target was a regular spiking pyramid, the probability of connectivity was only 1 in 40, and none of the 13 anatomically identified postsynaptic layer V targets had a slender apical dendrite terminating in layers IV/III. Morphological reconstructions indicated that layer III pyramids select target layer V cells whose apical dendrites pass within 50-100 microm of the soma of the presynaptic pyramid in layer III and which have overlapping apical dendritic tufts in the superficial layers. The probability that a layer V cell would innervate a layer III pyramid lying within 250 microm of its apical dendrite was much lower (one in 58). Both presynaptic layer III pyramids and their large postsynaptic layer V targets could therefore access similar inputs in layers I/II, while small layer V pyramids could not. One prediction from the present data would be that neither descending layer V inputs to the striatum or thalamus, nor transcallosal connections would be readily activated by longer distance cortico-cortical "feedback" connections that terminated in layers I/II. These could, however, activate corticofugal pathways to the superior colliculus or pons, both directly and via layer III.

  2. Presynaptic and postsynaptic regulation of muscle contractions in the ascarid nematode Ascaris suum: a target for drug action.

    Science.gov (United States)

    Trailović, S M; Zurovac, Z; Gruborović, S; Marjanović, D S; Nedeljković-Trailović, J

    2016-11-01

    The aim of this study was to determine the role in contractions of postsynaptic nicotinic acetylcholine (nACh) and γ-aminobutyric acid (GABA) receptors, in the bag region of Ascaris suum muscle cells, as well as the role of synaptic receptors between interneurons and motor neurons in the dorsal and ventral nerve cord. We have measured the isometric contractions of isolated segments of A. suum, with or without the nerve cord (dorsal or ventral). Contractions were caused by increasing concentrations of ACh or by electrical field stimulation (EFS). Based on our results, the presence of the nerve cord is essential for the contractile effects of ACh. The EC50 value of ACh for innervated muscle strips was 10.88 μm. Unlike intact (innervated) preparations, there was no contraction of the muscle flaps when the nerve cord was mechanically removed. Furthermore, continuous EFS produced stable contractions of innervated muscle strips, but they are not sensitive to mecamylamine (100 μm). However, GABA (30 μm) significantly inhibited the EFS-induced contractions. EFS with the same characteristics did not cause muscle contractions of denervated muscle strips, but EFS with a wider pulse induced the increasing of tone and irregular contractions. These contractions were completely insensitive to the effect of GABA. The EC50 for ACh did not differ between the dorsal and ventral segments (9.83 μm and 9.45 μm), while GABA exhibited features of competitive and non-competitive antagonists, regardless of whether it acted on the dorsal or ventral segments of A. suum. It is obvious that drugs will be more effective if they act on both the synaptic and extrasynaptic nACh and GABA receptors.

  3. Regulation of phosphorylation at Ser(1303) of GluN2B receptor in the postsynaptic density.

    Science.gov (United States)

    Prabhu Ramya, R; Suma Priya, S; Mayadevi, M; Omkumar, R V

    2012-12-01

    Neuronal N-methyl-D-aspartate subtype of ionotropic glutamate receptor (NMDAR) that plays essential roles in excitatory synaptic transmission is regulated by phosphorylation. However, the kinases and phosphatases involved in this regulation are not completely known. We show that the GluN2B subunit of NMDAR is phosphorylated at Ser(1303) by protein kinase C (PKC) and is dephosphorylated by protein phosphatase 1 (PP1), but not protein phosphatase 2A (PP2A) in isolated postsynaptic density (PSD). Although PSD is known to harbor PKC, PP1 and PP2A, their ability to regulate phosphorylation of GluN2B-Ser(1303) would depend on the accessibility of GluN2B-Ser(1303) to these proteins. Since PSD preparation is likely to maintain the organization of its component proteins as inside neurons, accessibility of kinases and phosphatases to GluN2B-Ser(1303)in vivo would be addressed by experiments using this system. Using an antibody specific for the phosphorylated state of GluN2B-Ser(1303) we demonstrate that PP1 is the major phosphatase in rat brain PSD that can dephosphorylate the GluN2B-Ser(1303) endogenous to PSD. We also show that PKC present in PSD can phosphorylate GluN2B-Ser(1303). The events reported here might be important in regulating GluN2B-Ser(1303) phosphorylation in vivo. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. A fast BK-type KCa current acts as a postsynaptic modulator of temporal selectivity for communication signals

    Directory of Open Access Journals (Sweden)

    Tsunehiko eKohashi

    2014-09-01

    Full Text Available Temporal patterns of spiking often convey behaviorally relevant information. Various synaptic mechanisms and intrinsic membrane properties can influence neuronal selectivity to temporal patterns of input. However, little is known about how synaptic mechanisms and intrinsic properties together determine the temporal selectivity of neuronal output. We tackled this question by recording from midbrain electrosensory neurons in mormyrid fish, in which the processing of temporal intervals between communication signals can be studied in a reduced in vitro preparation. Mormyrids communicate by varying interpulse intervals (IPIs between electric pulses. Within the midbrain posterior exterolateral nucleus (ELp, the temporal patterns of afferent spike trains are filtered to establish single-neuron IPI tuning. We performed whole-cell recording from ELp neurons in a whole-brain preparation and examined the relationship between intrinsic excitability and IPI tuning. We found that spike frequency adaptation of ELp neurons was highly variable. Postsynaptic potentials (PSPs of strongly adapting (phasic neurons were more sharply tuned to IPIs than weakly adapting (tonic neurons. Further, the synaptic filtering of IPIs by tonic neurons was more faithfully converted into variation in spiking output, particularly at short IPIs. Pharmacological manipulation under current- and voltage-clamp revealed that tonic firing is mediated by a fast, large-conductance Ca2+-activated K+ (KCa current (BK that speeds up action potential repolarization. These results suggest that BK currents can shape the temporal filtering of sensory inputs by modifying both synaptic responses and PSP-to-spike conversion. Slow SK-type KCa currents have previously been implicated in temporal processing. Thus, both fast and slow KCa currents can fine-tune temporal selectivity.

  5. A Single Postnatal Dose of Dexamethasone Enhances Memory of Rat Pups Later in Life.

    Directory of Open Access Journals (Sweden)

    Kuen-Jer Tsai

    Full Text Available Postnatal dexamethasone (Dex therapy is associated with adverse neurodevelopmental outcomes, which might be related to its timing of administration. We used time-dated pregnant Wistar albino rats, whose litters were divided into experimental (Dex and control groups intraperitoneally administered one dose of Dex (0.5 mg/kg or normal saline (NS, respectively, at either day 1 (P1 or 7 (P7. The magnitude of the contextual freezing response and performance on the Morris water maze were significantly higher in the Dex-P7 group than in those of the other groups at P56. Dendritic spine density, membranous expression of the N-methyl-d-aspartate receptor (NMDAR subunit NR2A/2B, and postsynaptic density-95 (PSD-95 were significantly higher in the Dex-P7 group than in the other groups. Furthermore, cytosolic expression of nuclear factor kappa B (NF-κB and phosphatidylinositol 3-kinase (PI3K was significantly higher in the Dex group than in NS group. Moreover, Dex administration at P7 increased cell proliferation, neuronal differentiation, and the survival of newly born neurons in the dentate gyrus. These results suggest Dex at P7 enhances the acquisition of contextual fear and spatial memory later in life due to the modulation of the newly born neurons, increase in dendritic spine number, and NMDAR expression.

  6. ZL006, a small molecule inhibitor of PSD-95/nNOS interaction, does not induce antidepressant-like effects in two genetically predisposed rat models of depression and control animals

    DEFF Research Database (Denmark)

    Tillmann, Sandra; Pereira, Vitor Silva; Liebenberg, Nico

    2017-01-01

    been proposed. This disruption can be achieved using small molecule inhibitors such as ZL006, which has attracted attention as ischemic stroke therapy in rodents and has been proposed as a potential novel treatment for depression. Based on this, our aim was to translate these findings to animal models...... of depression to elucidate antidepressant-like properties in more detail. In the present study, we administered ZL006 to two established animal models of depression and control rodents. Following treatment, we measured locomotion in the Open Field and depressive-like behavior in the Forced Swim Test and Tail...

  7. Cdk5-dependent phosphorylation of liprinα1 mediates neuronal activity-dependent synapse development.

    Science.gov (United States)

    Huang, Huiqian; Lin, Xiaochen; Liang, Zhuoyi; Zhao, Teng; Du, Shengwang; Loy, Michael M T; Lai, Kwok-On; Fu, Amy K Y; Ip, Nancy Y

    2017-08-15

    The experience-dependent modulation of brain circuitry depends on dynamic changes in synaptic connections that are guided by neuronal activity. In particular, postsynaptic maturation requires changes in dendritic spine morphology, the targeting of postsynaptic proteins, and the insertion of synaptic neurotransmitter receptors. Thus, it is critical to understand how neuronal activity controls postsynaptic maturation. Here we report that the scaffold protein liprinα1 and its phosphorylation by cyclin-dependent kinase 5 (Cdk5) are critical for the maturation of excitatory synapses through regulation of the synaptic localization of the major postsynaptic organizer postsynaptic density (PSD)-95. Whereas Cdk5 phosphorylates liprinα1 at Thr701, this phosphorylation decreases in neurons in response to neuronal activity. Blockade of liprinα1 phosphorylation enhances the structural and functional maturation of excitatory synapses. Nanoscale superresolution imaging reveals that inhibition of liprinα1 phosphorylation increases the colocalization of liprinα1 with PSD-95. Furthermore, disruption of liprinα1 phosphorylation by a small interfering peptide, siLIP, promotes the synaptic localization of PSD-95 and enhances synaptic strength in vivo. Our findings collectively demonstrate that the Cdk5-dependent phosphorylation of liprinα1 is important for the postsynaptic organization during activity-dependent synapse development.

  8. Detergent-dependent separation of postsynaptic density, membrane rafts and other subsynaptic structures from the synaptic plasma membrane of rat forebrain.

    Science.gov (United States)

    Zhao, LiYing; Sakagami, Hiroyuki; Suzuki, Tatsuo

    2014-10-01

    We systematically investigated the purification process of post-synaptic density (PSD) and post-synaptic membrane rafts (PSRs) from the rat forebrain synaptic plasma membranes by examining the components and the structures of the materials obtained after the treatment of synaptic plasma membranes with TX-100, n-octyl β-d-glucoside (OG) or 3-([3-cholamidopropyl]dimethylammonio)-2-hydroxy-1-propanesulfonate (CHAPSO). These three detergents exhibited distinct separation profiles for the synaptic subdomains. Type I and type II PSD proteins displayed mutually exclusive distribution. After TX-100 treatment, type I PSD was recovered in two fractions: a pellet and an insoluble fraction 8, which contained partially broken PSD-PSR complexes. Conventional PSD was suggested to be a mixture of these two PSD pools and did not contain type II PSD. An association of type I PSD with PSRs was identified in the TX-100 treatment, and those with type II PSD in the OG and CHAPSO treatments. An association of GABA receptors with gephyrin was easily dissociated. OG at a high concentration solubilized the type I PSD proteins. CHAPSO treatment resulted in a variety of distinct fractions, which contained certain novel structures. Two different pools of GluA, either PSD or possibly raft-associated, were identified in the OG and CHAPSO treatments. These results are useful in advancing our understanding of the structural organization of synapses at the molecular level. We systematically investigated the purification process of post-synaptic density (PSD) and synaptic membrane rafts by examining the structures obtained after treatment of the SPMs with TX-100, n-octyl β-d-glucoside or CHAPSO. Differential distribution of type I and type II PSD, synaptic membrane rafts, and other novel subdomains in the SPM give clues to understand the structural organization of synapses at the molecular level. © 2014 International Society for Neurochemistry.

  9. Postsynaptic target regulates functional responses induced by 5-HT3 serotonin receptors on axonal varicosities of NG108-15 hybrid neuroblastoma cells.

    Science.gov (United States)

    Rondé, P; Nichols, R A

    2001-01-01

    Rat brain presynaptic 5-HT3 serotonin receptors, members of the ligand-gated ion channel superfamily, induce changes in nerve terminal [Ca2+]i in a manner distinct from that found for somatic 5-HT3 receptors. Here, we assessed the role of postsynaptic target in regulating the nature of presynaptic receptor-induced responses, using the hybrid neuroblastoma cell line NG108-15 as a model neuronal system that expresses 5-HT3 receptors. Using immunocytochemistry, 5-HT3 receptors were found to be present on the presynaptic-like varicosities of differentiated NG108-15 cells, indicating that these receptors possess an inherent ability to localize to potential presynaptic sites. In the absence of postsynaptic target, 5-HT3 receptors localized to the varicosities induce rapid but transient changes in [Ca2+]i that were initiated by voltage-gated Ca2+ channels, as assessed using Ca2+ channel blockers, these properties being typical of those found for somatic 5-HT3 receptors. In co-cultures containing rat myotubes, with which NG108-15 cells form functional cholinergic synapses, the 5-HT3 receptor-induced changes in [Ca2+]i in the axonal varicosities shifted over time (three to 10 days) to that found for brain nerve endings: sustained responses that were insensitive to blockade by antagonists of voltage-gated Ca2+ channels. The effect of co-culturing myotubes with the NG108-15 cells was mimicked by conditioned media from myotube cultures. These results indicate that regulatory molecules from the target postsynaptic cell dictate the functional responses elicited by presynaptic 5-HT3 receptors. Because the target-induced changes required several days before they were evident, we hypothesize that changes in protein expression, perhaps the consequence of altered gene regulation, underlie the changes in the responses to 5-HT3 receptor activation in the axonal varicosities of this neuronal cell line.

  10. Synaptic Plasticity and NO-cGMP-PKG Signaling Regulate Pre- and Postsynaptic Alterations at Rat Lateral Amygdala Synapses Following Fear Conditioning

    Science.gov (United States)

    Ota, Kristie T.; Monsey, Melissa S.; Wu, Melissa S.; Schafe, Glenn E.

    2010-01-01

    In vertebrate models of synaptic plasticity, signaling via the putative “retrograde messenger” nitric oxide (NO) has been hypothesized to serve as a critical link between functional and structural alterations at pre- and postsynaptic sites. In the present study, we show that auditory Pavlovian fear conditioning is associated with significant and long-lasting increases in the expression of the postsynaptically-localized protein GluR1 and the presynaptically-localized proteins synaptophysin and synapsin in the lateral amygdala (LA) within 24 hrs following training. Further, we show that rats given intra-LA infusion of either the NR2B-selective antagonist Ifenprodil, the NOS inhibitor 7-Ni, or the PKG inhibitor Rp-8-Br-PET-cGMPS exhibit significant decreases in training-induced expression of GluR1, synaptophysin, and synapsin immunoreactivity in the LA, while those rats infused with the PKG activator 8-Br-cGMP exhibit a significant increase in these proteins in the LA. In contrast, rats given intra-LA infusion of the NO scavenger c-PTIO exhibit a significant decrease in synapsin and synaptophysin expression in the LA, but no significant impairment in the expression of GluR1. Finally, we show that intra-LA infusions of the ROCK inhibitor Y-27632 or the CaMKII inhibitor KN-93 impair training-induced expression of GluR1, synapsin, and synaptophysin in the LA. These findings suggest that the NO-cGMP-PKG, Rho/ROCK, and CaMKII signaling pathways regulate fear memory consolidation, in part, by promoting both pre- and post-synaptic alterations at LA synapses. They further suggest that synaptic plasticity in the LA during auditory fear conditioning promotes alterations at presynaptic sites via NO-driven “retrograde signaling”. PMID:20574537

  11. Role of Splice Variants of Gtf2i, a Transcription Factor Localizing at Postsynaptic Sites, and Its Relation to Neuropsychiatric Diseases

    Directory of Open Access Journals (Sweden)

    Yoshinori Shirai

    2017-02-01

    Full Text Available We previously reported that various mRNAs were associated with postsynaptic density (PSD purified from rat forebrain. Among the thousands of PSD-associated mRNAs, we highlight the biology of the general transcription factor II-I (Gtf2i mRNA, focusing on the significance of its versatile splicing for targeting its own mRNA into dendrites, regulation of translation, and the effects of Gtf2i expression level as well as its relationship with neuropsychiatric disorders.

  12. Prenatal melamine exposure impairs spatial cognition and hippocampal synaptic plasticity by presynaptic and postsynaptic inhibition of glutamatergic transmission in adolescent offspring.

    Science.gov (United States)

    An, Lei; Sun, Wei

    2017-03-05

    Our previous studies showed that prenatal melamine exposure (PME) could impair spatial cognition and hippocampal long-term potentiation (LTP). More importantly, the synaptic dysfunction induced by PME was associated with the probability of presynaptic glutamate release. Considering the crucial role of the other form of synaptic plasticity, long-term depression (LTD), in some types of learning and memory process, the aim of present study was to investigate if the hippocampal LTD and cognitive flexibility were affected. And then we attempted to explore the underlying mechanism. The animal model was produced by melamine exposure throughout gestational period with 400mg/kg bodyweight, the male offspring rats were used in the study. Morris water maze (MWM) test was performed, and then LTD was recorded from Schaffer collaterals to CA1 region in the hippocampus. Behavioral test showed that learning, reference memory and re-acquisition learning abilities were impaired significantly by PME. The field excitatory postsynaptic potentials (fEPSPs) slopes of LTD were significantly higher after PME. Furthermore, the data of whole-cell patch-clamp experiments showed that PME markedly diminished the frequencies of spontaneous EPSCs (sEPSCs) and simultaneously reduced the amplitude of sEPSCs. In conclusion, PME inhibited glutamate transmission presynaptically and postsynaptically which could contribute importantly to the depressed hippocampal synaptic plasticity and further induced cognitive deficits in MWM tests. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. A New Component in Long-Term Synaptic Plasticity: Upregulation of Kinesin in the Pre- and Postsynaptic Neurons of the Gill-Withdrawal Reflex

    Science.gov (United States)

    Puthanveettil, Sathyanarayanan V; Monje, Francisco J; Miniaci, Maria Concetta; Choi, Yun-Beom; Karl, Kevin A; Khandros, Eugene; Gawinowicz, Mary Ann; Sheetz, Michael P.; Kandel, Eric R.

    2009-01-01

    Summary To explore how gene products, required for the initiation of synaptic growth, move from the cell body of the sensory neurons to its presynaptic terminals, and from the cell body of the motor neuron to its postsynaptic dendritic spines, we have searched for anterograde transport machinery in both the sensory and motor neurons of the gill-withdrawal reflex of Aplysia. We found that the induction of long-term facilitation (LTF) by repeated applications of serotonin, a modulatory transmitter released during learning in Aplysia, requires upregulation of kinesin heavy chain (KHC) in both pre- and postsynaptic neurons. Indeed, upregulation of KHC in the presynaptic neurons alone is sufficient for the induction of LTF. However, KHC is not required for the persistence of LTF. Thus, in addition to transcriptional activation in the nucleus and local protein synthesis at the synapse, our studies have identified a third component critical for long-term learning-related plasticity: the coordinated upregulation of kinesin-mediated transport. PMID:19041756

  14. Postsynaptic density protein transcripts are differentially modulated by minocycline alone or in add-on to haloperidol: Implications for treatment resistant schizophrenia.

    Science.gov (United States)

    Buonaguro, Elisabetta F; Tomasetti, Carmine; Chiodini, Paolo; Marmo, Federica; Latte, Gianmarco; Rossi, Rodolfo; Avvisati, Livia; Iasevoli, Felice; de Bartolomeis, Andrea

    2017-04-01

    In this study, we investigated whether minocycline, a second-generation tetracycline proposed as an add-on to antipsychotics in treatment-resistant schizophrenia (TRS), may affect the expression of Homer and Arc postsynaptic density (PSD) transcripts, implicated in synaptic regulation. Minocycline was administered alone or with haloperidol in rats exposed or not to ketamine, mimicking acute glutamatergic psychosis or naturalistic conditions, respectively. Arc expression was significantly reduced by minocycline compared with controls. Minocycline in combination with haloperidol also significantly reduced Arc expression compared with both controls and haloperidol alone. Moreover, haloperidol/minocycline combination significantly affected Arc expression in cortical regions, while haloperidol alone was ineffective on cortical gene expression. These results suggest that minocycline may strongly affect the expression of Arc as mediated by haloperidol, both in terms of quantitative levels and of topography of haloperidol-related expression. It is noteworthy that no significant pre-treatment effect was found, suggesting that pre-exposure to ketamine did not grossly affect gene expression. Minocycline was not found to significantly affect haloperidol-related Homer1a expression. No significant changes in Homer1b/c expression were observed. These results are consistent with previous observations that minocycline may modulate postsynaptic glutamatergic transmission, affecting distinct downstream pathways initiated by N-methyl-D-aspartate (NMDA) receptor modulation, i.e. Arc-mediated but not Homer1a-mediated pathways.

  15. Altered Synaptic Marker Abundance in the Hippocampal Stratum Oriens of Ts65Dn Mice is Associated with Exuberant Expression of Versican

    Directory of Open Access Journals (Sweden)

    Matthew D Howell

    2012-01-01

    Full Text Available DS (Down syndrome, resulting from trisomy of chromosome 21, is the most common cause of genetic mental retardation; however, the molecular mechanisms underlying the cognitive deficits are poorly understood. Growing data indicate that changes in abundance or type of CSPGs (chondroitin sulfate proteoglycans in the ECM (extracellular matrix can influence synaptic structure and plasticity. The purpose of this study was to identify changes in synaptic structure in the hippocampus in a model of DS, the Ts65Dn mouse, and to determine the relationship to proteoglycan abundance and/or cleavage and cognitive disability. We measured synaptic proteins by ELISA and changes in lectican expression and processing in the hippocampus of young and old Ts65Dn mice and LMCs (littermate controls. In young (5 months old Ts65Dn hippocampal extracts, we found a significant increase in the postsynaptic protein PSD-95 (postsynaptic density 95 compared with LMCs. In aged (20 months old Ts65Dn hippocampus, this increase was localized to hippocampal stratum oriens extracts compared with LMCs. Aged Ts65Dn mice exhibited impaired hippocampal-dependent spatial learning and memory in the RAWM (radial-arm water maze and a marked increase in levels of the lectican versican V2 in stratum oriens that correlated with the number of errors made in the final RAWM block. Ts65Dn stratum oriens PNNs (perineuronal nets, an extension of the ECM enveloping mostly inhibitory interneurons, were dispersed over a larger area compared with LMC mice. Taken together, these data suggest a possible association with alterations in the ECM and inhibitory neurotransmission in the Ts65Dn hippocampus which could contribute to cognitive deficits.

  16. Melanopsin ganglion cells extend dendrites into the outer retina during early postnatal development.

    Science.gov (United States)

    Renna, Jordan M; Chellappa, Deepa K; Ross, Christopher L; Stabio, Maureen E; Berson, David M

    2015-09-01

    Melanopsin ganglion cells express the photopigment melanopsin and are the first functional photoreceptors to develop in the mammalian retina. They have been shown to play a variety of important roles in visual development and behavior in the early postnatal period (Johnson et al., 2010; Kirkby and Feller, 2013; Rao et al., 2013; Renna et al., 2011). Here, we probed the maturation of the dendritic arbors of melanopsin ganglion cells during this developmental period in mice. We found that some melanopsin ganglion cells (mainly the M1-subtype) transiently extend their dendrites not only into the inner plexiform layer (where they receive synaptic inputs from bipolar and amacrine cells) but also into the outer plexiform layer, where in mature retina, rod and cone photoreceptors are thought to contact only bipolar and horizontal cells. Thus, some immature melanopsin ganglion cells are biplexiform. This feature is much less common although still present in the mature retina. It reaches peak incidence 8-12 days after birth, before the eyes open and bipolar cells are sufficiently mature to link rods and cones to ganglion cells. At this age, some outer dendrites of melanopsin ganglion cells lie in close apposition to the axon terminals of cone photoreceptors and express a postsynaptic marker of glutamatergic transmission, postsynaptic density-95 protein (PSD-95). These findings raise the possibility of direct, monosynaptic connections between cones and melanopsin ganglion cells in the early postnatal retina. We provide a detailed description of the developmental profile of these processes and consider their possible functional and evolutionary significance. © 2015 Wiley Periodicals, Inc.

  17. Conductive Hearing Loss Has Long-Lasting Structural and Molecular Effects on Presynaptic and Postsynaptic Structures of Auditory Nerve Synapses in the Cochlear Nucleus.

    Science.gov (United States)

    Clarkson, Cheryl; Antunes, Flora M; Rubio, Maria E

    2016-09-28

    Sound deprivation by conductive hearing loss increases hearing thresholds, but little is known about the response of the auditory brainstem during and after conductive hearing loss. Here, we show in young adult rats that 10 d of monaural conductive hearing loss (i.e., earplugging) leads to hearing deficits that persist after sound levels are restored. Hearing thresholds in response to clicks and frequencies higher than 8 kHz remain increased after a 10 d recovery period. Neural output from the cochlear nucleus measured at 10 dB above threshold is reduced and followed by an overcompensation at the level of the lateral lemniscus. We assessed whether structural and molecular substrates at auditory nerve (endbulb of Held) synapses in the cochlear nucleus could explain these long-lasting changes in hearing processing. During earplugging, vGluT1 expression in the presynaptic terminal decreased and synaptic vesicles were smaller. Together, there was an increase in postsynaptic density (PSD) thickness and an upregulation of GluA3 AMPA receptor subunits on bushy cells. After earplug removal and a 10 d recovery period, the density of synaptic vesicles increased, vesicles were also larger, and the PSD of endbulb synapses was larger and thicker. The upregulation of the GluA3 AMPAR subunit observed during earplugging was maintained after the recovery period. This suggests that GluA3 plays a role in plasticity in the cochlear nucleus. Our study demonstrates that sound deprivation has long-lasting alterations on structural and molecular presynaptic and postsynaptic components at the level of the first auditory nerve synapse in the auditory brainstem. Despite being the second most prevalent form of hearing loss, conductive hearing loss and its effects on central synapses have received relatively little attention. Here, we show that 10 d of monaural conductive hearing loss leads to an increase in hearing thresholds, to an increased central gain upstream of the cochlear nucleus at

  18. Immunoglobulins from amyotrophic lateral sclerosis patients enhance the frequency of glycine-mediated spontaneous inhibitory postsynaptic currents in rat hypoglossal motoneurons

    Directory of Open Access Journals (Sweden)

    Anđus P.R.

    2007-01-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is a devastating, still incurable neurological disorder affecting upper and lower motoneurons. Passive transfer of the disease occurs when immunoglobulins from ALS patients are injected into experimental animals. It is suggested that ALS IgGs cause excitotoxicity by acting on voltage-gated Ca2+ channels. We reported previously that ALS IgGs increase spontaneous release of glutamate in hippocampal neurons. Since these cells are not normally affected in ALS, we here studied the effect of ALS IgGs on hypoglossal motoneurons in rat brain-stem slices. The frequency of spontaneous glycine-mediated inhibitory postsynaptic currents (sIPSCs was augmented, but not that of miniature ones (mIPSCs, thus pointing to an indirect effect on release.

  19. Differential effects of presynaptic versus postsynaptic adenosine A2A receptor blockade on Δ9-tetrahydrocannabinol (THC) self-administration in squirrel monkeys.

    Science.gov (United States)

    Justinová, Zuzana; Redhi, Godfrey H; Goldberg, Steven R; Ferré, Sergi

    2014-05-07

    Different doses of an adenosine A2A receptor antagonist MSX-3 [3,7-dihydro-8-[(1E)-2-(3-ethoxyphenyl)ethenyl]-7 methyl-3-[3-(phosphooxy)propyl-1-(2 propynil)-1H-purine-2,6-dione] were found previously to either decrease or increase self-administration of cannabinoids delta-9-tetrahydrocannabinol (THC) or anandamide in squirrel monkeys. It was hypothesized that the decrease observed with a relatively low dose of MSX-3 was related to blockade of striatal presynaptic A2A receptors that modulate glutamatergic neurotransmission, whereas the increase observed with a higher dose was related to blockade of postsynaptic A2A receptors localized in striatopallidal neurons. This hypothesis was confirmed in the present study by testing the effects of the preferential presynaptic and postsynaptic A2A receptor antagonists SCH-442416 [2-(2-furanyl)-7-[3-(4-methoxyphenyl)propyl]-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine] and KW-6002 [(E)-1, 3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione], respectively, in squirrel monkeys trained to intravenously self-administer THC. SCH-442416 produced a significant shift to the right of the THC self-administration dose-response curves, consistent with antagonism of the reinforcing effects of THC. Conversely, KW-6002 produced a significant shift to the left, consistent with potentiation of the reinforcing effects of THC. These results show that selectively blocking presynaptic A2A receptors could provide a new pharmacological approach to the treatment of marijuana dependence and underscore corticostriatal glutamatergic neurotransmission as a possible main mechanism involved in the rewarding effects of THC.

  20. Ca2+-binding protein-1 facilitates and forms a postsynaptic complex with Cav1.2 (L-type) Ca2+ channels.

    Science.gov (United States)

    Zhou, Hong; Kim, Seong-Ah; Kirk, Elizabeth A; Tippens, Alyssa L; Sun, Hong; Haeseleer, Françoise; Lee, Amy

    2004-05-12

    Ca2+-binding protein-1 (CaBP1) is a Ca2+-binding protein that is closely related to calmodulin (CaM) and localized in somatodendritic regions of principal neurons throughout the brain, but how CaBP1 participates in postsynaptic Ca2+ signaling is not known. Here, we describe a novel role for CaBP1 in the regulation of Ca2+ influx through Ca(v)1.2 (L-type) Ca2+ channels. CaBP1 interacts directly with the alpha1 subunit of Ca(v)1.2 at sites that also bind CaM. CaBP1 binding to one of these sites, the IQ domain, is Ca2+ dependent and competitive with CaM binding. The physiological significance of this interaction is supported by the association of Ca(v)1.2 and CaBP1 in postsynaptic density fractions purified from rat brain. Moreover, in double-label immunofluorescence experiments, CaBP1 and Ca(v)1.2 colocalize in numerous cell bodies and dendrites of neurons, particularly in pyramidal cells in the CA3 region of the hippocampus and in the dorsal cortex. In electrophysiological recordings of cells transfected with Ca(v)1.2, CaBP1 greatly prolonged Ca2+ currents, prevented Ca2+-dependent inactivation, and caused Ca2+-dependent facilitation of currents evoked by step depolarizations and repetitive stimuli. These effects contrast with those of CaM, which promoted strong Ca2+-dependent inactivation of Ca(v)1.2 with these same voltage protocols. Our findings reveal how Ca2+-binding proteins, such as CaM and CaBP1, differentially adjust Ca2+ influx through Ca(v)1.2 channels, which may specify diverse modes of Ca2+ signaling in neurons.

  1. Activity-dependent alterations in the sensitivity to BDNF-TrkB signaling may promote excessive dendritic arborization and spinogenesis in fragile X syndrome in order to compensate for compromised postsynaptic activity.

    Science.gov (United States)

    Kim, Sang Woo; Cho, Kyoung Joo

    2014-10-01

    Fragile X syndrome (FXS), the most common cause of inherited human mental retardation, results from the loss of function of fragile X mental retardation protein (FMRP). To date, most researchers have thought that FXS neural pathologies are primarily caused by extreme dendritic branching and spine formation. With this rationale, several researchers attempted to prune dendritic branches and reduce the number of spines in FXS animal models. We propose that increased dendritic arborization and spinogenesis in FXS are developed rather as secondary compensatory responses to counteract the compromised postsynaptic activity during uncontrollable metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD). When postsynaptic and electrical activities become dampened in FXS, dendritic trees can increase their sensitivity to brain-derived neurotrophic factor (BDNF) by using the molecular sensor called eukaryotic elongation factor 2 (eEF2) and taking advantage of the tight coupling of mGluR and BDNF-TrkB signaling pathways. Then, this activity-dependent elevation of the BDNF signaling can strategically alter dendritic morphologies to foster branching and develop spine structures in order to improve the postsynaptic response in FXS. Our model suggests a new therapeutic rationale for FXS: correcting the postsynaptic and electrical activity first, and then repairing structural abnormalities of dendrites. Then, it may be possible to successfully fix the dendritic morphologies without affecting the survival of neurons. Our theory may also be generalized to explain aberrant dendritic structures observed in other neurobehavioral diseases, such as tuberous sclerosis, Rett syndrome, schizophrenia, and channelopathies, which accompany high postsynaptic and electrical activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. The mechanism of 5-lipoxygenase in the impairment of learning and memory in rats subjected to chronic unpredictable mild stress.

    Science.gov (United States)

    Luo, Ying; Kuang, Shengnan; Xue, Lai; Yang, Junqing

    2016-12-01

    To examine the mechanism of 5-lipoxygenase (5-LO) in the learning and memory dysfunction in rats subjected to chronic unpredictable mild stress (CUMS). Eighty rats were divided into eight groups: the 0.5% sodium carboxymethyl cellulose solution (NaCMC)-treated group, empty vector (LV-Mock)-treated group, CUMS+NaCMC-treated group, CUMS+sertraline-treated group, CUMS+caffeic acid (10mg/kg)-treated group, CUMS+caffeic acid (30mg/kg)-treated group, CUMS+LV-Mock-treated group, and CUMS+5-LO-silencers lentiviral vectors (LV-si-5-LO)-treated group, n=10. Sucrose preference tests were performed to assess depression-like behavior. The Morris water maze and step-down tests were used to evaluate learning and memory performance. The levels of inflammatory cytokines, malondialdehyde, and the activity of superoxide dismutase (SOD) were detected to estimate inflammation and oxidative stress. Changes in 5-LO mRNA and protein were detected using reverse transcription polymerase chain reaction and Western blotting. The expression of synaptophysin, postsynaptic density-95 (PSD-95), and brain-derived neurotrophic factor (BDNF) in the hippocampus were measured using immunohistochemical staining. Treatment with caffeic acid or LV-si-5-LO increased sucrose consumption, decreased escape latency and increased the number of platform crosses in the Morris water maze test, and decreased the number of errors and prolonged the latency in the step-down test. We observed a decreased expression of 5-LO, and levels of malondialdehyde, leukotriene-B4, tumor necrosis factor-α, and interleukin-6, while the protein levels of synaptophysin, PSD-95, BDNF, and the activity of SOD were increased in the hippocampus of the CUMS-treated rats. CUMS-induced impairment in learning and memory could be triggered by an inflammatory response in the rat hippocampus, which results in oxidative stress injury and impacts the synaptic plasticity of hippocampal neurons. Inhibition of the activity or expression of 5-LO

  3. Tyrosine phosphatases such as SHP-2 act in a balance with Src-family kinases in stabilization of postsynaptic clusters of acetylcholine receptors

    Directory of Open Access Journals (Sweden)

    Rüegg Markus A

    2007-07-01

    Full Text Available Abstract Background Development of neural networks requires that synapses are formed, eliminated and stabilized. At the neuromuscular junction (NMJ, agrin/MuSK signaling, by triggering downstream pathways, causes clustering and phosphorylation of postsynaptic acetylcholine receptors (AChRs. Postnatally, AChR aggregates are stabilized by molecular pathways that are poorly characterized. Gain or loss of function of Src-family kinases (SFKs disassembles AChR clusters at adult NMJs in vivo, whereas AChR aggregates disperse rapidly upon withdrawal of agrin from cultured src-/-;fyn-/- myotubes. This suggests that a balance between protein tyrosine phosphatases (PTPs and protein tyrosine kinases (PTKs such as those of the Src-family may be essential in stabilizing clusters of AChRs. Results We have analyzed the role of PTPs in maintenance of AChR aggregates, by adding and then withdrawing agrin from cultured myotubes in the presence of PTP or PTK inhibitors and quantitating remaining AChR clusters. In wild-type myotubes, blocking PTPs with pervanadate caused enhanced disassembly of AChR clusters after agrin withdrawal. When added at the time of agrin withdrawal, SFK inhibitors destabilized AChR aggregates but concomitant addition of pervanadate rescued cluster stability. Likewise in src-/-;fyn-/- myotubes, in which agrin-induced AChR clusters form normally but rapidly disintegrate after agrin withdrawal, pervanadate addition stabilized AChR clusters. The PTP SHP-2, known to be enriched at the NMJ, associated and colocalized with MuSK, and agrin increased this interaction. Specific SHP-2 knockdown by RNA interference reduced the stability of AChR clusters in wild-type myotubes. Similarly, knockdown of SHP-2 in adult mouse soleus muscle by electroporation of RNA interference constructs caused disassembly of pretzel-shaped AChR-rich areas in vivo. Finally, we found that src-/-;fyn-/- myotubes contained elevated levels of SHP-2 protein. Conclusion Our data

  4. Processing Semblances Induced through Inter-Postsynaptic Functional LINKs, Presumed Biological Parallels of K-Lines Proposed for Building Artificial Intelligence

    Science.gov (United States)

    Vadakkan, Kunjumon I.

    2011-01-01

    The internal sensation of memory, which is available only to the owner of an individual nervous system, is difficult to analyze for its basic elements of operation. We hypothesize that associative learning induces the formation of functional LINK between the postsynapses. During memory retrieval, the activation of either postsynapse re-activates the functional LINK evoking a semblance of sensory activity arriving at its opposite postsynapse, nature of which defines the basic unit of internal sensation – namely, the semblion. In neuronal networks that undergo continuous oscillatory activity at certain levels of their organization re-activation of functional LINKs is expected to induce semblions, enabling the system to continuously learn, self-organize, and demonstrate instantiation, features that can be utilized for developing artificial intelligence (AI). This paper also explains suitability of the inter-postsynaptic functional LINKs to meet the expectations of Minsky’s K-lines, basic elements of a memory theory generated to develop AI and methods to replicate semblances outside the nervous system. PMID:21845180

  5. Combined optical and topographic imaging reveals different arrangements of human RAD54 with presynaptic and postsynaptic RAD51–DNA filaments

    Science.gov (United States)

    Sanchez, Humberto; Kertokalio, Aryandi; van Rossum-Fikkert, Sari; Kanaar, Roland; Wyman, Claire

    2013-01-01

    Essential genome transactions, such as homologous recombination, are achieved by concerted and dynamic interactions of multiple protein components with DNA. Which proteins do what and how, will be reflected in their relative arrangements. However, obtaining high-resolution structural information on the variable arrangements of these complex assemblies is a challenge. Here we demonstrate the versatility of a combined total internal reflection fluorescence and scanning force microscope (TIRF-SFM) to pinpoint fluorescently labeled human homologous recombination protein RAD54 interacting with presynaptic (ssDNA) and postsynaptic (dsDNA) human recombinase RAD51 nucleoprotein filaments. Labeled proteins were localized by superresolution imaging on complex structures in the SFM image with high spatial accuracy. We observed some RAD54 at RAD51 filament ends, as expected. More commonly, RAD54 interspersed along RAD51–DNA filaments. RAD54 promotes RAD51-mediated DNA strand exchange and has been described to both stabilize and destabilize RAD51–DNA filaments. The different architectural arrangements we observe for RAD54 with RAD51–DNA filaments may reflect the diverse roles of this protein in homologous recombination. PMID:23801766

  6. Sustained Recreational Use of Ecstasy Is Associated with Altered Pre and Postsynaptic Markers of Serotonin Transmission in Neocortical Areas: A PET Study with [11C]DASB and [11C]MDL 100907

    OpenAIRE

    Urban, Nina BL; Girgis, Ragy R.; Talbot, Peter S.; Kegeles, Lawrence S.; Xu, X.; Frankle, W Gordon; Hart, Carl L.; Slifstein, Mark; Abi-Dargham, Anissa; Laruelle, Marc

    2012-01-01

    3,4-Methylenedioxymethamphetamine (MDMA), the main psychoactive component of the recreational drug ecstasy, is a potent serotonin (5-HT) releaser. In animals, MDMA induces 5-HT depletion and toxicity in 5-HT neurons. The aim of this study was to investigate both presynaptic (5-HT transporter, SERT) and postsynaptic (5-HT2A receptor) markers of 5-HT transmission in recently abstinent chronic MDMA users compared with matched healthy controls. We hypothesized that MDMA use is associated with low...

  7. The Effects of Acute and Chronic Ethanol Exposure on Presynaptic and Postsynaptic GABAA Receptor Function in Cultured Cortical and Hippocampal Neurons

    Science.gov (United States)

    Fleming, Rebekah L.; Manis, Paul B.; Morrow, A. Leslie

    2009-01-01

    Decades after ethanol was first described as a GABA mimetic, the precise mechanisms that produce the acute effects of ethanol and the physiological adaptations that underlie ethanol tolerance and dependence remain unclear. While a substantial body of evidence suggests that ethanol acts on GABAergic neurotransmission to enhance inhibition in the CNS, the precise mechanisms underlying the physiological effects of both acute and chronic ethanol exposure are still under investigation. We have used in vitro ethanol exposure followed by recording of miniature inhibitory postsynaptic currents (mIPSCs) to determine whether acute or chronic ethanol exposure directly alters synaptic GABAA receptor function or GABA release in cultured cortical and hippocampal neurons. Acute ethanol exposure slightly increased the duration of mIPSCs in hippocampal neurons but did not alter mIPSC kinetics in cortical neurons. Acute ethanol exposure did not change mIPSC frequency in either hippocampal or cortical neurons. One day of chronic ethanol exposure produced a transient decrease in mIPSC duration in cortical neurons but did not alter mIPSC kinetics in hippocampal neurons. Chronic ethanol exposure did not change mIPSC frequency in either hippocampal or cortical neurons. Chronic ethanol exposure also did not produce substantial cross-tolerance to a benzodiazepine in either hippocampal or cortical neurons. The results suggest that ethanol exposure in vitro has limited effects on synaptic GABAAR function and action-potential independent GABA release in cultured neurons and suggests that ethanol exposure in cultured cortical and hippocampal neurons may not reproduce all of the effects that occur in vivo and in acute brain slices. PMID:20004338

  8. The GABAergic projection of the dentate gyrus to hippocampal area CA3 of the rat: pre- and postsynaptic actions after seizures.

    Science.gov (United States)

    Treviño, Mario; Gutiérrez, Rafael

    2005-09-15

    The glutamatergic granule cells of the dentate gyrus transiently express GABAergic markers after seizures. Here we show that when this occurs, their activation produces (i) GABA(A) receptor-mediated synaptic field responses in CA3, with the physiological and pharmacological characteristics of mossy fibre transmission, and (ii) GABA(A) receptor-mediated collateral inhibition. Control hippocampal slices present, on stimulation of the dentate gyrus, population responses in stratum lucidum, which are blocked by ionotropic glutamate receptor antagonists. By contrast, in slices from rats subjected to seizures in vivo, dentate activation additionally produces GABA(A) receptor-mediated field synaptic responses in the presence of glutamate receptor antagonists. One-dimensional current source density analysis confirmed the spatial coincidence of the glutamatergic and GABAergic dendritic currents. The GABA(A) receptor-mediated field responses show frequency-dependent facilitation and strong inhibition during activation of metabotropic glutamate receptors. In the presence of glutamate receptor blockers, a conditioning pulse delivered to one site of the dentate gyrus inhibits the population synaptic response and the afferent volley provoked by the activation of a second site, in a bicuculline-sensitive manner. In accordance with this, antidromic responses evoked by mossy fibre activation were enhanced by perfusion of bicuculline. Our results suggest that, for GABA receptor-dependent field potentials to be detected, a considerable number of boutons of a well-defined GABAergic pathway should simultaneously release GABA to act on a large number of receptors. Therefore, putative GABA release from the mossy fibres acts on pre- and postsynaptic sites to affect hippocampal activity at the network level after seizures.

  9. Hypothyroidism in the adult rat causes incremental changes in brain-derived neurotrophic factor, neuronal and astrocyte apoptosis, gliosis, and deterioration of postsynaptic density.

    Science.gov (United States)

    Cortés, Claudia; Eugenin, Eliseo; Aliaga, Esteban; Carreño, Leandro J; Bueno, Susan M; Gonzalez, Pablo A; Gayol, Silvina; Naranjo, David; Noches, Verónica; Marassi, Michelle P; Rosenthal, Doris; Jadue, Cindy; Ibarra, Paula; Keitel, Cecilia; Wohllk, Nelson; Court, Felipe; Kalergis, Alexis M; Riedel, Claudia A

    2012-09-01

    Adult hypothyroidism is a highly prevalent condition that impairs processes, such as learning and memory. Even though tetra-iodothyronine (T(4)) treatment can overcome the hypothyroidism in the majority of cases, it cannot fully recover the patient's learning capacity and memory. In this work, we analyzed the cellular and molecular changes in the adult brain occurring with the development of experimental hypothyroidism. Adult male Sprague-Dawley rats were treated with 6-propyl-2-thiouracil (PTU) for 20 days to induce hypothyroidism. Neuronal and astrocyte apoptosis were analyzed in the hippocampus of control and hypothyroid adult rats by confocal microscopy. The content of brain-derived neurotrophic factor (BDNF) was analyzed using enzyme-linked immunosorbent assay (ELISA) and in situ hybridization. The glutamatergic synapse and the postsynaptic density (PSD) were analyzed by electron microscopy. The content of PSD proteins like tyrosine receptor kinase B (TrkB), p75, and N-methyl-D-aspartate receptor (NMDAr) were analyzed by immunoblot. We observed that the hippocampus of hypothyroid adult rats displayed increased apoptosis levels in neurons and astrocyte and reactive gliosis compared with controls. Moreover, we found that the amount of BDNF mRNA was higher in the hippocampus of hypothyroid rats and the content of TrkB, the receptor for BDNF, was reduced at the PSD of the CA3 region of hypothyroid rats, compared with controls. We also observed that the glutamatergic synapses from the stratum radiatum of CA3 from hypothyroid rats, contained thinner PSDs than control rats. This observation was in agreement with a reduced content of NMDAr subunits at the PSD in hypothyroid animals. Our data suggest that adult hypothyroidism affects the hippocampus by a mechanism that alters the composition of PSD, reduces neuronal and astrocyte survival, and alters the content of the signaling neurotrophic factors, such as BDNF.

  10. Stress suppresses and learning induces plasticity in CA3 of rat hippocampus: a three-dimensional ultrastructural study of thorny excrescences and their postsynaptic densities.

    Science.gov (United States)

    Stewart, M G; Davies, H A; Sandi, C; Kraev, I V; Rogachevsky, V V; Peddie, C J; Rodriguez, J J; Cordero, M I; Donohue, H S; Gabbott, P L A; Popov, V I

    2005-01-01

    Chronic stress and spatial training have been proposed to affect hippocampal structure and function in opposite ways. Previous morphological studies that addressed structural changes after chronic restraint stress and spatial training were based on two-dimensional morphometry which does not allow a complete morphometric characterisation of synaptic features. Here, for the first time in such studies, we examined these issues by using three-dimensional (3-D) reconstructions of electron microscope images taken from thorny excrescences of hippocampal CA3 pyramidal cells. Ultrastructural alterations in postsynaptic densities (PSDs) of thorny excrescences receiving input from mossy fibre boutons were also determined, as were changes in numbers of multivesicular bodies (endosome-like structures) within thorny excrescences and dendrites. Quantitative 3-D data demonstrated retraction of thorny excrescences after chronic restraint stress which was reversed after water maze training, whilst water maze training alone increased thorny excrescence volume and number of thorns per thorny excrescence. PSD surface area was unaffected by restraint stress but water maze training increased both number and area of PSDs per thorny excrescence. In restrained rats that were water maze trained PSD volume and surface area increased significantly. The proportion of perforated PSDs almost doubled after water maze training and restraint stress. Numbers of endosome-like structures in thorny excrescences decreased after restraint stress and increased after water maze training. These findings demonstrate that circuits involving contacts between mossy fibre terminals and CA3 pyramidal cells at stratum lucidum level are affected conversely by water maze training and chronic stress, confirming the remarkable plasticity of CA3 dendrites. They provide a clear illustration of the structural modifications that occur after life experiences noted for their different impact on hippocampal function.

  11. Association of the AMPA receptor-related postsynaptic density proteins GRIP and ABP with subsets of glutamate-sensitive neurons in the rat retina.

    Science.gov (United States)

    Gábriel, Robert; de Souza, Sunita; Ziff, Edward B; Witkovsky, Paul

    2002-07-22

    We used specific antibodies against two postsynaptic density proteins, GRIP (glutamate receptor interacting protein) and ABP (AMPA receptor-binding protein), to study their distribution in the rat retina. In the central nervous system, it has been shown that both proteins bind strongly to the AMPA glutamate receptor (GluR) 2/3 subunits, but not other GluRs, through a set of three PDZ domains. Western blots detected a single GRIP protein that was virtually identical in retina and brain, whereas retinal ABP corresponded to only one of three ABP peptides found in brain. The retinal distributions of GluR2/3, GRIP, and ABP immunoreactivity (IR) were similar but not identical. GluR2/3 immunoreactivity (IR) was abundant in both plexiform layers and in large perikarya. ABP IR was concentrated in large perikarya but was sparse in the plexiform layers, whereas GRIP IR was relatively more abundant in the plexiform layers than in perikarya. Immunolabel for these three antibodies consisted of puncta ABP IR was examined by double labeling subclasses of retinal neuron with characteristic marker proteins, e.g., calbindin. GRIP, ABP, and GluR2/3 IR were detected in horizontal cells, dopaminergic and glycinergic AII amacrine cells and large ganglion cells. Immunolabel was absent in rod bipolar and weak or absent in cholinergic amacrine cells. By using the tyramide method of signal amplification, a colocalization of GluR2/3 was found with either GRIP or ABP in horizontal cell terminals, and perikarya of amacrine and ganglion cells. Our results show that ABP and GRIP colocalize with GluR2/3 in particular subsets of retinal neuron, as was previously established for certain neurons in the brain. Copyright 2002 Wiley-Liss, Inc.

  12. Dexmedetomidine promotes the recovery of the field excitatory postsynaptic potentials (fEPSPs) in rat hippocampal slices exposed to oxygen-glucose deprivation.

    Science.gov (United States)

    Kim, Sung-Eun; Ko, Il-Gyu; Kim, Chang-Ju; Chung, Jun-Young; Yi, Jae-Woo; Choi, Jeong-Hyun; Jang, Myung-Soo; Han, Jin-Hee

    2016-09-19

    Dexmedetomidine (DEX), a selective α2 adrenergic agonist, is an anesthetic and sedative agent, and is reported to exert neuroprotective effects after hypoxic ischemia. However, there are few studies on the electrophysiological effect of DEX in hippocampal slices under ischemic conditions. The effects of DEX on field potential in hippocampal slices exposed to oxygen-glucose deprivation (OGD) were evaluated. Hippocampal slices were prepared from rats, and the evoked field excitatory postsynaptic potentials (fEPSPs) were recorded using the MED 64 system. Hypoxic-ischemia was induced by perfusion with glucose-free artificial cerebrospinal fluid (aCSF) bubbled with 95% N2 and 5% CO2, and hippocampal slices were perfused with DEX-added aCSF before, during, and after OGD induction. In the normal hippocampal slices, perfusion with 1 and 10μM DEX did not significantly decrease the normalized fEPSP amplitude, but 100μM DEX significantly reduced the fEPSP amplitude compared with its baseline control. The induction of OGD remarkably decreased the fEPSP amplitude, whereas the pre-, co-, and post-treatment of 10μM DEX gradually promoted recovery after washing out, and consequently the amplitude of fEPSP in DEX pre-, co-, and post-treated OGD slices were significantly higher than that in the untreated OGD slices at 10min and 60min after washing out. In particular, co-treatment with DEX conspicuously promoted the recovery of the fEPSP amplitude at the beginning of washing out. These results suggest the possibility of DEX as a therapeutic agent to prevent hypoxic-ischemic brain damage and promote functional recovery after ischemia. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Alterations of Synaptic Proteins in the Hippocampus of Mouse Offspring Induced by Developmental Lead Exposure.

    Science.gov (United States)

    Yu, Haiyang; Liao, Yingjun; Li, Tingting; Cui, Yan; Wang, Gaoyang; Zhao, Fenghong; Jin, Yaping

    2016-12-01

    Lead exposure can cause cognitive dysfunction in children, thus it still raises important public health concerns in China and other countries. However, the underlying molecular mechanisms are still not well defined. In this study, we aimed to elucidate the mechanisms underlying lead neurotoxicity by focusing on alterations of synaptic proteins in the mouse hippocampus at the early life. Mother mice and their offspring were exposed to 0, 0.5, 1.0, and 2.0 g/L lead via drinking water from the first day of gestation until postnatal day (PND) 40. Synaptic ultrastructure and expressions of postsynaptic density protein-95 (PSD-95), neuronal nitric oxide synthase (nNOS) and synaptophysin (SYP) at both protein and gene levels in the hippocampus were analyzed. The results revealed that developmental lead exposure caused a diminished postsynaptic density in the hippocampus. Moreover, the protein levels of PSD-95, nNOS, and SYP decreased significantly due to developmental lead exposure. On the other hand, the messenger RNA (mRNA) levels of PSD-95 and SYP decreased significantly in PND 40 mice exposed to lead. Collectively, developmental lead exposure might result in decreased protein and gene expressions of both presynaptic and postsynaptic proteins. Our findings raised a possibility that alterations of synaptic proteins in the hippocampus induced by lead exposure at the early life might serve an important role for the subsequent intellectual impairments, e.g., deficits in spatial learning and memory ability at later ages shown in our recently published paper.

  14. Single Prazosin Infusion in Prelimbic Cortex Fosters Extinction of Amphetamine-Induced Conditioned Place Preference.

    Science.gov (United States)

    Latagliata, Emanuele C; Lo Iacono, Luisa; Chiacchierini, Giulia; Sancandi, Marco; Rava, Alessandro; Oliva, Valeria; Puglisi-Allegra, Stefano

    2017-01-01

    Exposure to drug-associated cues to induce extinction is a useful strategy to contrast cue-induced drug seeking. Norepinephrine (NE) transmission in medial prefrontal cortex has a role in the acquisition and extinction of conditioned place preference induced by amphetamine. We have reported recently that NE in prelimbic cortex delays extinction of amphetamine-induced conditioned place preference (CPP). A potential involvement of α1-adrenergic receptors in the extinction of appetitive conditioned response has been also suggested, although their role in prelimbic cortex has not been yet fully investigated. Here, we investigated the effects of the α1-adrenergic receptor antagonist prazosin infusion in the prelimbic cortex of C57BL/6J mice on expression and extinction of amphetamine-induced CPP. Acute prelimbic prazosin did not affect expression of amphetamine-induced CPP on the day of infusion, while in subsequent days it produced a clear-cut advance of extinction of preference for the compartment previously paired with amphetamine (Conditioned stimulus, CS). Moreover, prazosin-treated mice that had extinguished CS preference showed increased mRNA expression of brain-derived neurotrophic factor (BDNF) and post-synaptic density 95 (PSD-95) in the nucleus accumbens shell or core, respectively, thus suggesting that prelimbic α1-adrenergic receptor blockade triggers neural adaptations in subcortical areas that could contribute to the extinction of cue-induced drug-seeking behavior. These results show that the pharmacological blockade of α1-adrenergic receptors in prelimbic cortex by a single infusion is able to induce extinction of amphetamine-induced CPP long before control (vehicle) animals, an effect depending on contingent exposure to retrieval, since if infused far from or after reactivation it did not affect preference. Moreover, they suggest strongly that the behavioral effects depend on post-treatment neuroplasticity changes in corticolimbic network, triggered

  15. Inhibition of spontaneous recovery of fear by mGluR5 after prolonged extinction training.

    Directory of Open Access Journals (Sweden)

    Sheng-Chun Mao

    Full Text Available Fear behavior is vital for survival and involves learning contingent associations of non-threatening cues with aversive stimuli. In contrast, excessive levels of fear can be maladaptive and lead to anxiety disorders. Generally, extensive sessions of extinction training correlates with reduced spontaneous recovery. The molecular mechanisms underlying the long-term inhibition of fear recovery following repeated extinction training are not fully understood. Here we show that in rats, prolonged extinction training causes greater reduction in both fear-potentiated startle and spontaneous recovery. This effect was specifically blocked by metabotropic glutamate receptor 5 (mGluR5, but not by mGluR1 antagonists and by a protein synthesis inhibitor. Similar inhibition of memory recovery following prolonged extinction training was also observed in mice. In agreement with the instrumental role of mGluR5 in the prolonged inhibition of fear recovery, we found that FMR1-/- mice which exhibit enhanced mGluR5-mediated signaling exhibit lower spontaneous recovery of fear after extinction training than wild-type littermates. At the molecular level, we discovered that prolonged extinction training reversed the fear conditioning-induced increase in surface expression of GluR1, AMPA/NMDA ratio, postsynaptic density-95 (PSD-95 and synapse-associated protein-97 (SAP97. Accordingly, delivery of Tat-GluR2(3Y, a synthetic peptide that blocks AMPA receptor endocytosis, inhibited prolonged extinction training-induced inhibition of fear recovery. Together, our results demonstrate that prolonged extinction training results in the mGluR5-dependent long-term inhibition of fear recovery. This effect may involve the degradation of original memory and may explain the beneficial effects of prolonged exposure therapy for the treatment of phobias.

  16. β2-Adrenergic Receptor Activation Suppresses the Rat Phenethylamine Hallucinogen-Induced Head Twitch Response: Hallucinogen-Induced Excitatory Post-synaptic Potentials as a Potential Substrate

    Directory of Open Access Journals (Sweden)

    Gerard J. Marek

    2018-02-01

    Full Text Available 5-Hydroxytryptamine2A (5-HT2A receptors are enriched in layers I and Va of the rat prefrontal cortex and neocortex and their activation increases the frequency of glutamatergic excitatory post-synaptic potentials/currents (EPSP/Cs onto layer V pyramidal cells. A number of other G-protein coupled receptors (GPCRs are also enriched in cortical layers I and Va and either induce (α1-adrenergic and orexin2 or suppress (metabotropic glutamate2 [mGlu2], adenosine A1, μ-opioid both 5-HT-induced EPSCs and head twitches or head shakes induced by the phenethylamine hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI. Another neurotransmitter receptor also localized to apparent thalamocortical afferents to layers I and Va of the rat prefrontal cortex and neocortex is the β2-adrenergic receptor. Therefore, we conducted preliminary electrophysiological experiments with rat brain slices examining the effects of epinephrine on electrically-evoked EPSPs following bath application of DOI (3 μM. Epinephrine (0.3–10 μM suppressed the late EPSPs produced by electrical stimulation and DOI. The selective β2-adrenergic receptor antagonist ICI-118,551 (300 nM resulted in a rightward shift of the epinephrine concentration-response relationship. We also tested the selective β2-adrenergic receptor agonist clenbuterol and the antagonist ICI-118,551 on DOI-induced head twitches. Clenbuterol (0.3–3 mg/kg, i.p. suppressed DOI (1.25 mg/kg, i.p.-induced head twitches. This clenbuterol effect appeared to be at least partially reversed by the selective β2-adrenergic receptor antagonist ICI-118,553 (0.01–1 mg/kg, i.p., with significant reversal at doses of 0.1 and 1 mg/kg. Thus, β2-adrenergic receptor activation reverses the effects of phenethylamine hallucinogens in the rat prefrontal cortex. While Gi/Go-coupled GPCRs have previously been shown to suppress both the electrophysiological and behavioral effects of 5-HT2A receptor activation in the mPFC, the present work

  17. Distinct roles of Drosophila cacophony and Dmca1D Ca(2+) channels in synaptic homeostasis: genetic interactions with slowpoke Ca(2+) -activated BK channels in presynaptic excitability and postsynaptic response.

    Science.gov (United States)

    Lee, Jihye; Ueda, Atsushi; Wu, Chun-Fang

    2014-01-01

    Ca(2+) influx through voltage-activated Ca(2+) channels and its feedback regulation by Ca(2+) -activated K(+) (BK) channels is critical in Ca(2+) -dependent cellular processes, including synaptic transmission, growth and homeostasis. Here we report differential roles of cacophony (CaV 2) and Dmca1D (CaV 1) Ca(2+) channels in synaptic transmission and in synaptic homeostatic regulations induced by slowpoke (slo) BK channel mutations. At Drosophila larval neuromuscular junctions (NMJs), a well-established homeostatic mechanism of transmitter release enhancement is triggered by experimentally suppressing postsynaptic receptor response. In contrast, a distinct homeostatic adjustment is induced by slo mutations. To compensate for the loss of BK channel control presynaptic Sh K(+) current is upregulated to suppress transmitter release, coupled with a reduction in quantal size. We demonstrate contrasting effects of cac and Dmca1D channels in decreasing transmitter release and muscle excitability, respectively, consistent with their predominant pre- vs. postsynaptic localization. Antibody staining indicated reduced postsynaptic GluRII receptor subunit density and altered ratio of GluRII A and B subunits in slo NMJs, leading to quantal size reduction. Such slo-triggered modifications were suppressed in cac;;slo larvae, correlated with a quantal size reversion to normal in double mutants, indicating a role of cac Ca(2+) channels in slo-triggered homeostatic processes. In Dmca1D;slo double mutants, the quantal size and quantal content were not drastically different from those of slo, although Dmca1D suppressed the slo-induced satellite bouton overgrowth. Taken together, cac and Dmca1D Ca(2+) channels differentially contribute to functional and structural aspects of slo-induced synaptic modifications. Copyright © 2013 Wiley Periodicals, Inc.

  18. Egr-1 antisense oligodeoxynucleotide administration into the olfactory bulb impairs olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx.

    Science.gov (United States)

    Ganesh, Ambigapathy; Bogdanowicz, Wieslaw; Balamurugan, Krishnaswamy; Ragu Varman, Durairaj; Rajan, Koilmani Emmanuvel

    2012-08-30

    Postsynaptic densities (PSDs) contain proteins that regulate synaptic transmission. We examined two important examples of these, calcium/calmodulin-dependent protein kinase II (CaMKII) and PSD-95, in regard to the functional role of early growth response gene-1 (egr-1) in regulation of olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx (family Pteropodidae). To test whether activation of egr-1 in the olfactory bulb (OB) is required for olfactory memory of these bats, bilaterally canulated individuals were infused with antisense (AS) or non-sense (NS)-oligodeoxynucleotides (ODN) of egr-1, or with phosphate buffer saline (PBS), 2h before the olfactory training. Our results showed that behavioral training significantly up-regulates immediate early gene (IEG) EGR-1 and key synaptic proteins Synaptotagmin-1(SYT-1), CaMKII and PSD-95, and phosphorylation of CaMKII in the OB at the protein level per se. Subsequently, we observed that egr-1 antisense-ODN infusion in the OB impaired olfactory memory and down regulates the expression of CaMKII and PSD-95, and the phosphorylation of CaMKII but not SYT-1. In contrast, NS-ODN or PBS had no effect on the expression of the PSDs CaMKII or PSD-95, or on the phosphorylation of CaMKII. When the egr-1 NS-ODN was infused in the OB after training for the novel odor there was no effect on olfactory memory. These findings suggest that egr-1 control the activation of CaMKII and PSD-95 during the process of olfactory memory formation. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Estrogen receptor beta and 2-arachydonoylglycerol mediate the suppressive effects of estradiol on frequency of postsynaptic currents in gonadotropin-releasing hormone neurons of metestrous mice: an acute slice electrophysiological study

    Directory of Open Access Journals (Sweden)

    Flóra eBálint

    2016-03-01

    Full Text Available Gonadotropin-releasing hormone (GnRH neurons are controlled by 17β-estradiol (E2 contributing to the steroid feedback regulation of the reproductive axis. In rodents, E2 exerts a negative feedback effect upon GnRH neurons throughout the estrus-diestrus phase of the ovarian cycle. The present study was undertaken to reveal the role of estrogen receptor subtypes in the mediation of the E2 signal and elucidate the downstream molecular machinery of suppression. The effect of E2 administration at low physiological concentration (10 pM on GnRH neurons in acute brain slices obtained from metestrous GnRH-GFP mice was studied under paradigms of blocking or activating estrogen receptor subtypes and interfering with retrograde 2-arachydonoylglycerol (2-AG signaling. Whole-cell patch clamp recordings revealed that E2 significantly diminished the frequency of spontaneous postsynaptic currents (sPSCs in GnRH neurons (49. 62±7.6% which effect was abolished by application of the ERα/β blocker Faslodex (1 µM. Pretreatment of the brain slices with cannabinoid receptor type 1 (CB1 inverse agonist AM251 (1 µM and intracellularly applied endocannabinoid synthesis blocker THL (10 µM significantly attenuated the effect of E2 on the sPSCs. E2 remained effective in the presence of TTX indicating a direct action of E2 on GnRH cells. The ERβ specific agonist DPN (10 pM also significantly decreased the frequency of miniature postsynaptic currents (mPSCs in GnRH neurons. In addition, the suppressive effect of E2 was completely blocked by the selective ERβ antagonist PHTPP (1 µM indicating that ERβ is required for the observed rapid effect of the E2. In contrast, the ERα agonist PPT (10 pM or the membrane-associated G protein-coupled estrogen receptor (GPR30 agonist G1 (10 pM had no significant effect on the frequency of mPSCs in these neurons. AM251 and THL significantly abolished the effect of E2 whereas AM251 eliminated the action of DPN on the mPSCs. These

  20. Effect of xiaoyaosan decoction on learning and memory deficit in rats induced by chronic immobilization stress.

    Science.gov (United States)

    Meng, Zhen-Zhi; Chen, Jia-Xu; Jiang, You-Ming; Zhang, Han-Ting

    2013-01-01

    Xiaoyaosan (XYS) decoction is a famous prescription which can protect nervous system from stress and treat liver stagnation and spleen deficiency syndrome (LSSDS). In this experiment, we observed the effect of XYS decoction on chronic immobilization stress (CIS) induced learning and memory deficit in rats from behaviors and changes of proteins in hippocampus. We used XYS decoction to treat CIS induced learning and memory deficit in rats with rolipram as positive control, used change of body weight and behavioral tests to determine whether the rats have LSSDS and have learning and memory deficit or not. We used Western blotting to determine the content of postsynaptic density protein 95 (PSD-95) and synaptophysin (SYP) in hippocampus. Results showed that XYS could improve the situation of slow weight gain induced by CIS, improve the ability of learning and memory, reverse the symptom of liver stagnation and spleen deficiency syndrome (LSSDS) in rats, and increase the levels of PSD-95 and SYP on the hippocampal nerve synapses. These findings suggested that XYS decoction may be helpful in reversing CIS induced learning and memory deficit by increasing the levels of PSD-95 and SYP on the hippocampal nerve synapses and improving synaptic plasticity.

  1. Effect of Xiaoyaosan Decoction on Learning and Memory Deficit in Rats Induced by Chronic Immobilization Stress

    Directory of Open Access Journals (Sweden)

    Zhen-Zhi Meng

    2013-01-01

    Full Text Available Xiaoyaosan (XYS decoction is a famous prescription which can protect nervous system from stress and treat liver stagnation and spleen deficiency syndrome (LSSDS. In this experiment, we observed the effect of XYS decoction on chronic immobilization stress (CIS induced learning and memory deficit in rats from behaviors and changes of proteins in hippocampus. We used XYS decoction to treat CIS induced learning and memory deficit in rats with rolipram as positive control, used change of body weight and behavioral tests to determine whether the rats have LSSDS and have learning and memory deficit or not. We used Western blotting to determine the content of postsynaptic density protein 95 (PSD-95 and synaptophysin (SYP in hippocampus. Results showed that XYS could improve the situation of slow weight gain induced by CIS, improve the ability of learning and memory, reverse the symptom of liver stagnation and spleen deficiency syndrome (LSSDS in rats, and increase the levels of PSD-95 and SYP on the hippocampal nerve synapses. These findings suggested that XYS decoction may be helpful in reversing CIS induced learning and memory deficit by increasing the levels of PSD-95 and SYP on the hippocampal nerve synapses and improving synaptic plasticity.

  2. Synaptic adhesion molecule IgSF11 regulates synaptic transmission and plasticity

    Science.gov (United States)

    Shin, Hyewon; van Riesen, Christoph; Whitcomb, Daniel; Warburton, Julia M.; Jo, Jihoon; Kim, Doyoun; Kim, Sun Gyun; Um, Seung Min; Kwon, Seok-kyu; Kim, Myoung-Hwan; Roh, Junyeop Daniel; Woo, Jooyeon; Jun, Heejung; Lee, Dongmin; Mah, Won; Kim, Hyun; Kaang, Bong-Kiun; Cho, Kwangwook; Rhee, Jeong-Seop; Choquet, Daniel; Kim, Eunjoon

    2016-01-01

    Summary Synaptic adhesion molecules regulate synapse development and plasticity through mechanisms including trans-synaptic adhesion and recruitment of diverse synaptic proteins. We report here that the immunoglobulin superfamily member 11 (IgSF11), a homophilic adhesion molecule preferentially expressed in the brain, is a novel and dual-binding partner of the postsynaptic scaffolding protein PSD-95 and AMPAR glutamate receptors (AMPARs). IgSF11 requires PSD-95 binding for its excitatory synaptic localization. In addition, IgSF11 stabilizes synaptic AMPARs, as shown by IgSF11 knockdown-induced suppression of AMPAR-mediated synaptic transmission and increased surface mobility of AMPARs, measured by high-throughput, single-molecule tracking. IgSF11 deletion in mice leads to suppression of AMPAR-mediated synaptic transmission in the dentate gyrus and long-term potentiation in the CA1 region of the hippocampus. IgSF11 does not regulate the functional characteristics of AMPARs, including desensitization, deactivation, or recovery. These results suggest that IgSF11 regulates excitatory synaptic transmission and plasticity through its tripartite interactions with PSD-95 and AMPARs. PMID:26595655

  3. Channel properties of Nax expressed in neurons.

    Directory of Open Access Journals (Sweden)

    Masahito Matsumoto

    Full Text Available Nax is a sodium-concentration ([Na+]-sensitive Na channel with a gating threshold of ~150 mM for extracellular [Na+] ([Na+]o in vitro. We previously reported that Nax was preferentially expressed in the glial cells of sensory circumventricular organs including the subfornical organ, and was involved in [Na+] sensing for the control of salt-intake behavior. Although Nax was also suggested to be expressed in the neurons of some brain regions including the amygdala and cerebral cortex, the channel properties of Nax have not yet been adequately characterized in neurons. We herein verified that Nax was expressed in neurons in the lateral amygdala of mice using an antibody that was newly generated against mouse Nax. To investigate the channel properties of Nax expressed in neurons, we established an inducible cell line of Nax using the mouse neuroblastoma cell line, Neuro-2a, which is endogenously devoid of the expression of Nax. Functional analyses of this cell line revealed that the [Na+]-sensitivity of Nax in neuronal cells was similar to that expressed in glial cells. The cation selectivity sequence of the Nax channel in cations was revealed to be Na+ ≈ Li+ > Rb+ > Cs+ for the first time. Furthermore, we demonstrated that Nax bound to postsynaptic density protein 95 (PSD95 through its PSD95/Disc-large/ZO-1 (PDZ-binding motif at the C-terminus in neurons. The interaction between Nax and PSD95 may be involved in promoting the surface expression of Nax channels because the depletion of endogenous PSD95 resulted in a decrease in Nax at the plasma membrane. These results indicated, for the first time, that Nax functions as a [Na+]-sensitive Na channel in neurons as well as in glial cells.

  4. Ghrelin receptor activity amplifies hippocampal N-methyl-d-aspartate receptor-mediated postsynaptic currents and increases phosphorylation of the GluN1 subunit at Ser896 and Ser897.

    Science.gov (United States)

    Muniz, Brandon G; Isokawa, Masako

    2015-12-01

    Although ghrelin and its cognate receptor growth hormone secretagogue receptor (GHSR1a) are highly localized in the hypothalamic nuclei for the regulation of metabolic states and feeding, GHSR1a is also highly localized in the hippocampus, suggesting its involvement in extra-hypothalamic functions. Indeed, exogenous application of ghrelin has been reported to improve hippocampal learning and memory. However, the underlying mechanism of ghrelin regulation of hippocampal functions is poorly understood. Here, we report ghrelin-promoted phosphorylation of GluN1 and amplified N-methyl-d-aspartate receptor (NMDAR)-mediated excitatory postsynaptic currents in the CA1 pyramidal cells of the hippocampus in slice preparations. The ghrelin-induced responses were sensitive to a GHSR1a antagonist and inverse agonist, and were absent in GHSR1a homozygous knock-out mice. These results indicated that activation of GHSR1a was critical in the ghrelin-induced enhancement of the NMDAR function. Interestingly, heterozygous mouse hippocampi were also insensitive to ghrelin treatment, suggesting that a slight reduction in the availability of GHSR1a may be sufficient to negate the effect of ghrelin on GluN1 phosphorylation and NMDAR channel activities. In addition, NMDAR-mediated spike currents, which are of dendritic origin, were blocked by the GHSR1a antagonist, suggesting the presence of GHSR1a on the pyramidal cell dendrites in physical proximity to NMDAR. Together with our findings on the localization of GHSR1a in the CA1 region of the hippocampus, which was shown by fluorescent ghrelin binding, immunoreactivity, and enhanced green fluorescent protein reporter gene expression, we conclude that the activation of GHSR1a favours rapid modulation of the NMDAR-mediated glutamatergic synaptic transmission by phosphorylating GluN1 in the hippocampus. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  5. Further studies on the nature of postsynaptic dopamine uptake and metabolism in rat striatum: sodium dependency and investigation of a possible role for carrier-mediated uptake into serotonin neurons

    Energy Technology Data Exchange (ETDEWEB)

    Schoepp, D.D.; Azzaro, A.J.

    1985-06-01

    The nature of postsynaptic sites involved in the uptake and metabolism of striatal 3,4-dihydroxyphenylethylamine (dopamine, DA) was investigated. The accumulation of (/sup 3/H)DA (10(-7) M) into slices of rat striatum was found to be greatly dependent on the presence of sodium ion in the incubation medium. However, the formation of the (/sup 3/H)dihydroxyphenylacetic acid (DOPAC) and (/sup 3/H)homovanillic acid (HVA) was only partially reduced in the absence of sodium. Inhibition of carrier-mediated DA neuronal uptake with nomifensine significantly decreased DA accumulation (18% of control) and (/sup 3/H)DOPAC formation (62% of control), but enhanced (/sup 3/H)HVA production (143% of control). Inhibition of the 5-hydroxytryptamine (5-HT, serotonin) neuronal uptake system with fluoxetine (10(-6) M) or selective 5-HT neuronal lesions with 5,7-dihydroxytryptamine (5,7-DHT) had no effect on (/sup 3/H)DOPAC or (/sup 3/H)HVA formed from (/sup 3/H)DA in the presence or absence of nomifensine. These results demonstrate that the uptake and subsequent metabolism of striatal DA to DOPAC and HVA is only partially dependent on carrier-mediated uptake mechanism(s) requiring sodium ion. These data support our previous findings suggesting a significant role for synaptic glial cell deamination and O-methylation of striatal DA. Further, experiments with fluoxetine or 5,7-DHT suggest that 5-HT neurons do not significantly contribute in the synaptic uptake and metabolism of striatal DA.

  6. The Me31B DEAD-box helicase localizes to postsynaptic foci and regulates expression of a CaMKII reporter mRNA in dendrites of Drosophila olfactory projection neurons

    Directory of Open Access Journals (Sweden)

    Jens Hillebrand

    2010-11-01

    Full Text Available mRNP granules at adult central synapses are postulated to regulate local mRNA translation and synapse plasticity. However, they are very poorly characterized in vivo. Here, in Drosophila olfactory synapses, we present early observations and characterization of candidate synaptic mRNP particles, one of which contains a widely conserved, DEAD-box helicase, Me31B. In Drosophila, Me31B is required for translational repression of maternal and miRNA-target mRNAs. A role in neuronal translational control is primarily suggested by Me31B’s localization, in cultured primary neurons, to neuritic mRNP granules that contain: i various translational regulators; ii CaMKII mRNA; and iii several P-body markers including the mRNA hydrolases, Dcp1 and Pcm/Xrn-1. In adult neurons, Me31B localizes to P-body like cytoplasmic foci/particles in neuronal soma. In addition it is present to synaptic foci that may lack RNA degradative enzymes and localize predominantly to dendritic elements of olfactory sensory and projection neurons. MARCM clones of projection-neurons mutant for Me31B show loss of both Me31B and Dcp1-positive dendritic puncta, suggesting potential interactions between these granule types. In projection neurons, expression of validated hairpin-RNAi constructs against Me31B causes visible knockdown of endogenous protein, as assessed by the brightness and number of Me31B puncta. Knockdown of Me31B also causes a substantial elevation in observed levels of a translational reporter of CaMKII, a postsynaptic protein whose mRNA has been shown to be localized to projection neuron dendrites and to be translationally regulated, at least in part through the miRNA pathway. Thus, neuronal Me31B is present in dendritic particles in vivo and is required for repression of a translationally regulated synaptic mRNA.

  7. Distinct expression of synaptic NR2A and NR2B in the central nervous system and impaired morphine tolerance and physical dependence in mice deficient in postsynaptic density-93 protein

    Directory of Open Access Journals (Sweden)

    Johns Roger A

    2008-10-01

    Full Text Available Abstract Postsynaptic density (PSD-93, a neuronal scaffolding protein, binds to and clusters N-methyl-D-aspartate receptor (NMDAR subunits NR2A and NR2B at cellular membranes in vitro. However, the roles of PSD-93 in synaptic NR2A and NR2B targeting in the central nervous system and NMDAR-dependent physiologic and pathologic processes are still unclear. We report here that PSD-93 deficiency significantly decreased the amount of NR2A and NR2B in the synaptosomal membrane fractions derived from spinal cord dorsal horn and forebrain cortex but did not change their levels in the total soluble fraction from either region. However, PSD-93 deficiency did not markedly change the amounts of NR2A and NR2B in either synaptosomal or total soluble fractions from cerebellum. In mice deficient in PSD-93, morphine dose-dependent curve failed to shift significantly rightward as it did in wild type (WT mice after acute and chronic morphine challenge. Unlike WT mice, PSD-93 knockout mice also showed marked losses of NMDAR-dependent morphine analgesic tolerance and associated abnormal sensitivity in response to mechanical, noxious thermal, and formalin-induced inflammatory stimuli after repeated morphine injection. In addition, PSD-93 knockout mice displayed dramatic loss of jumping activity, a typical NMDAR-mediated morphine withdrawal abstinence behavior. These findings indicate that impaired NMDAR-dependent neuronal plasticity following repeated morphine injection in PSD-93 knockout mice is attributed to PSD-93 deletion-induced alterations of synaptic NR2A and NR2B expression in dorsal horn and forebrain cortex neurons. The selective effect of PSD-93 deletion on synaptic NMDAR expression in these two major pain-related regions might provide the better strategies for the prevention and treatment of opioid tolerance and physical dependence.

  8. Comparison of Steroid Modulation of Spontaneous Inhibitory Postsynaptic Currents in Cultured Hippocampal Neurons and Steady-State Single-Channel Currents from Heterologously Expressed α1β2γ2L GABAA Receptors

    Science.gov (United States)

    Chakrabarti, Sampurna; Qian, Mingxing; Krishnan, Kathiresan; Covey, Douglas F.; Mennerick, Steven

    2016-01-01

    Neuroactive steroids are efficacious modulators of γ-aminobutyric acid type A receptor (GABAA) receptor function. The effects of steroids on the GABAA receptor are typically determined by comparing steady-state single-channel open probability or macroscopic peak responses elicited by GABA in the absence and presence of a steroid. Due to differences in activation conditions (exposure duration, concentration of agonist), it is not obvious whether modulation measured using typical experimental protocols can be used to accurately predict the effect of a modulator on native receptors under physiologic conditions. In the present study, we examined the effects of 14 neuroactive steroids and analogs on the properties of spontaneous inhibitory postsynaptic currents (sIPSCs) in cultured rat hippocampal neurons. The goal was to determine whether the magnitude of modulation of the decay time course of sIPSCs correlates with the extent of modulation and kinetic properties of potentiation as determined in previous single-channel studies. The steroids were selected to cover a wide range of efficacy on heterologously expressed rat α1β2γ2L GABAA receptors, ranging from essentially inert to highly efficacious (strong potentiators of single-channel and macroscopic peak responses). The data indicate a strong correlation between prolongation of the decay time course of sIPSCs and potentiation of single-channel open probability. Furthermore, changes in intracluster closed time distributions were the single best predictor of prolongation of sIPSCs. We infer that the information obtained in steady-state single-channel recordings can be used to forecast modulation of synaptic currents. PMID:26769414

  9. Ephrin-A5 and EphA5 interaction induces synaptogenesis during early hippocampal development.

    Directory of Open Access Journals (Sweden)

    Yukio Akaneya

    2010-08-01

    Full Text Available Synaptogenesis is a fundamental step in neuronal development. For spiny glutamatergic synapses in hippocampus and cortex, synaptogenesis involves adhesion of pre and postsynaptic membranes, delivery and anchorage of pre and postsynaptic structures including scaffolds such as PSD-95 and NMDA and AMPA receptors, which are glutamate-gated ion channels, as well as the morphological maturation of spines. Although electrical activity-dependent mechanisms are established regulators of these processes, the mechanisms that function during early development, prior to the onset of electrical activity, are unclear. The Eph receptors and ephrins provide cell contact-dependent pathways that regulate axonal and dendritic development. Members of the ephrin-A family are glycosyl-phosphatidylinositol-anchored to the cell surface and activate EphA receptors, which are receptor tyrosine kinases.Here we show that ephrin-A5 interaction with the EphA5 receptor following neuron-neuron contact during early development of hippocampus induces a complex program of synaptogenic events, including expression of functional synaptic NMDA receptor-PSD-95 complexes plus morphological spine maturation and the emergence of electrical activity. The program depends upon voltage-sensitive calcium channel Ca2+ fluxes that activate PKA, CaMKII and PI3 kinase, leading to CREB phosphorylation and a synaptogenic program of gene expression. AMPA receptor subunits, their scaffolds and electrical activity are not induced. Strikingly, in contrast to wild type, stimulation of hippocampal slices from P6 EphA5 receptor functional knockout mice yielded no NMDA receptor currents.These studies suggest that ephrin-A5 and EphA5 signals play a necessary, activity-independent role in the initiation of the early phases of synaptogenesis. The coordinated expression of the NMDAR and PSD-95 induced by eprhin-A5 interaction with EphA5 receptors may be the developmental switch that induces expression of AMPAR

  10. Maternal lead exposure decreases the levels of brain development and cognition-related proteins with concomitant upsurges of oxidative stress, inflammatory response and apoptosis in the offspring rats.

    Science.gov (United States)

    Hossain, Shahdat; Bhowmick, Sujan; Jahan, Sabrin; Rozario, Liza; Sarkar, Marzan; Islam, Saiful; Basunia, Mafroz Ahmed; Rahman, Azizur; Choudhury, Bazlul Karim; Shahjalal, Hussain

    2016-09-01

    The presence of lead (Pb) in fetal brain may affect brain development-related proteins. We studied whether gestational/lactational Pb-exposure affects oxidative stress, proinflammatory response, apoptosis and levels of brain development/cognition-related proteins, including presynaptic synaptosome-associated protein-25 (SNAP-25), postsynaptic density protein-95 (PSD-95), brain-derived neurotropic factor (BDNF), tyrosine receptor-kinase protein B (TrkB) and vesicular acetylcholine transporter (VAChT) in the offspring. Female Wistar rats were randomly divided into control and Pb-exposed mother groups. The Pb-exposed rats received 0.1% (w/v) Pb acetate via drinking water during pregnancy and lactation. Milk and mammary glands were collected from lactating mothers to measure milk/mammary gland levels of lipid peroxide (LPO), as indicator of oxidative stress and proinflammatory TNF-α. Afterwards, the pups were sacrificed to determine brain levels of Pb, LPO, TNF-α, cytochrome C, SNAP-25, PSD-95, BDNF, TrkB and VAChT. The levels of LPO and TNF-α increased in the milk/mammary glands of the Pb-exposed mothers, concurrently with increases in the levels of Pb, LPO, TNF-α and cytochrome C and decreases in the levels of SNAP-25, PSD-95, BDNF, TrkB and VAChT in the brains of their offspring. Our results demonstrate that Pb-exposure during development reduces the brain levels of PSD-95 and SNAP-25 (synaptogenesis-markers), with concomitant upsurges of oxidative stress, TNF-α and apoptosis in the offspring. Furthermore, BDNF-TrkB proteins that comprehend memory-related brain cognitions and/or VAChT that comprises cholinergic-neuromotor activities might be impaired by Pb-exposure. These findings provide evidence of toxic effects of Pb on brain development, at least, partially by decreasing the levels of PSD-95, SNAP-25 and other cognition-related proteins. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Treadmill exercise facilitates synaptic plasticity on dopaminergic neurons and fibers in the mouse model with Parkinson's disease.

    Science.gov (United States)

    Shin, Mal-Soon; Jeong, Ho-Young; An, Da-In; Lee, Hye-Yun; Sung, Yun-Hee

    2016-05-16

    Exercise for patients with Parkinson's disease (PD) helps to alleviate clinical symptoms such as tremor, balance instability, gait dysfunction, and rigidity. However, molecular mechanism about effect of exercise is poorly unknown. In this study, we investigated effect of exercise in synapse and dendritic spine of nigrostriatal dopaminergic neurons on mice with PD. The C57BL/6J male mice (n=40) were divided by sham group, sham-exercise treated group, 1-Methyl-4-phenyl-l,2,3,6-tetrahydropyridine (MPTP) treated group, and MPTP-exercise treated group. For exercise treatment, the mice were put on the treadmill to run for 8m/min, 30min/day, and 5 times/week for 2 weeks. Coordination ability was checked by rota rod test. Expression of tyrosine hydroxylase (TH), synaptophysin, and post-synaptic density protein 95 (PSD-95) was confirmed at substantia nigra pars compacta (SNpc) or striatum using western blotting, or immunohistochemistry. To check dendritic spine in striatum, we used Golgi staining. The results revealed that MPTP treated group displayed poor coordination ability compared with sham group. However, MPTP-exercise treated group showed good coordination ability compared with MPTP treated group. As well as, we also found that MPTP-exercise group increases expression of synaptophysin, PSD-95, TH, and dendritic spine in nigrostriatal dopaminergic neurons and fibers than MPTP treated group (pexercise may give beneficial effects to patients with PD by facilitating synaptic plasticity and increasing dendritic spines. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. PKA Inhibitor H89 (N-[2-p-bromocinnamylamino-ethyl]-5-isoquinolinesulfonamide Attenuates Synaptic Dysfunction and Neuronal Cell Death following Ischemic Injury

    Directory of Open Access Journals (Sweden)

    Juhyun Song

    2015-01-01

    Full Text Available The cyclic AMP-dependent protein kinase (PKA, which activates prosurvival signaling proteins, has been implicated in the expression of long-term potentiation and hippocampal long-term memory. It has come to light that H89 commonly known as the PKA inhibitor have diverse roles in the nervous system that are unrelated to its role as a PKA inhibitor. We have investigated the role of H89 in ischemic and reperfusion injury. First, we examined the expression of postsynaptic density protein 95 (PSD95, microtubule-associated protein 2 (MAP2, and synaptophysin in mouse brain after middle cerebral artery occlusion injury. Next, we examined the role of H89 pretreatment on the expression of brain-derived neurotrophic factor (BDNF, PSD95, MAP2, and the apoptosis regulators Bcl2 and cleaved caspase-3 in cultured neuroblastoma cells exposed to hypoxia and reperfusion injury. In addition, we investigated the alteration of AKT activation in H89 pretreated neuroblastoma cells under hypoxia and reperfusion injury. The data suggest that H89 may contribute to brain recovery after ischemic stroke by regulating neuronal death and proteins related to synaptic plasticity.

  13. Levodopa-Induced Dyskinesia Is Related to Indirect Pathway Medium Spiny Neuron Excitotoxicity: A Hypothesis Based on an Unexpected Finding

    Directory of Open Access Journals (Sweden)

    Svetlana A. Ivanova

    2016-01-01

    Full Text Available A serendipitous pharmacogenetic finding links the vulnerability to developing levodopa-induced dyskinesia to the age of onset of Huntington’s disease. Huntington’s disease is caused by a polyglutamate expansion of the protein huntingtin. Aberrant huntingtin is less capable of binding to a member of membrane-associated guanylate kinase family (MAGUKs: postsynaptic density- (PSD- 95. This leaves more PSD-95 available to stabilize NR2B subunit carrying NMDA receptors in the synaptic membrane. This results in increased excitotoxicity for which particularly striatal medium spiny neurons from the indirect extrapyramidal pathway are sensitive. In Parkinson’s disease the sensitivity for excitotoxicity is related to increased oxidative stress due to genetically determined abnormal metabolism of dopamine or related products. This probably also increases the sensitivity of medium spiny neurons for exogenous levodopa. Particularly the combination of increased oxidative stress due to aberrant dopamine metabolism, increased vulnerability to NMDA induced excitotoxicity, and the particular sensitivity of indirect pathway medium spiny neurons for this excitotoxicity may explain the observed increased prevalence of levodopa-induced dyskinesia.

  14. A novel recombinant 6Aβ15-THc-C chimeric vaccine (rCV02) mitigates Alzheimer's disease-like pathology, cognitive decline and synaptic loss in aged 3 × Tg-AD mice.

    Science.gov (United States)

    Yu, Yun-Zhou; Liu, Si; Wang, Hai-Chao; Shi, Dan-Yang; Xu, Qing; Zhou, Xiao-Wei; Sun, Zhi-Wei; Huang, Pei-Tang

    2016-06-03

    Alzheimer's disease (AD) is a neurodegenerative disorder that impairs memory and cognition. Targeting amyloid-β (Aβ) may be currently the most promising immunotherapeutic strategy for AD. In this study, a recombinant chimeric 6Aβ15-THc-C immunogen was formulated with alum adjuvant as a novel Aβ B-cell epitope candidate vaccine (rCV02) for AD. We examined its efficacy in preventing the cognitive deficit and synaptic impairment in 3 × Tg-AD mice. Using a toxin-derived carrier protein, the rCV02 vaccine elicited robust Aβ-specific antibodies that markedly reduced AD-like pathology and improved behavioral performance in 3 × Tg-AD mice. Along with the behavioral improvement in aged 3 × Tg-AD mice, rCV02 significantly decreased calpain activation concurrent with reduced soluble Aβ or oligomeric forms of Aβ, probably by preventing dynamin 1 and PSD-95 degradation. Our data support the hypothesis that reducing Aβ levels in rCV02-immunized AD mice increases the levels of presynaptic dynamin 1 and postsynaptic PSD-95 allowing functional recovery of cognition. In conclusion, this novel and highly immunogenic rCV02 shows promise as a new candidate prophylactic vaccine for AD and may be useful for generating rapid and strong Aβ-specific antibodies in AD patients with pre-existing memory Th cells generated after immunization with conventional tetanus toxoid vaccine.

  15. Antidepressant-like effects and possible mechanisms of amantadine on cognitive and synaptic deficits in a rat model of chronic stress.

    Science.gov (United States)

    Yu, Mei; Zhang, Yuan; Chen, Xiaoyu; Zhang, Tao

    2016-01-01

    The aim of this study was to examine whether amantadine (AMA), as a low-affinity noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, is able to improve cognitive deficits caused by chronic stress in rats. Male Wistar rats were divided into four groups: control, control + AMA, stress and stress + AMA groups. The chronic stress model combined chronic unpredictable stress (CUS) with isolated feeding. Animals were exposed to CUS continued for 21 days. AMA (25 mg/kg) was administrated p.o. for 20 days from the 4th day of CUS to the 23rd. Weight and sucrose consumption were measured during model establishing period. Spatial memory was evaluated using the Morris water maze (MWM) test. Following MWM testing, both long-term potentiation (LTP) and depotentiation were recorded in the hippocampal CA1 region. NR2B and postsynaptic density protein 95 (PSD-95) proteins were measured by Western-blot analysis. AMA increased weight and sucrose consumption of stressed rats. Spatial memory and reversal learning in stressed rats were impaired relative to controls, whereas AMA significantly attenuated cognitive impairment. AMA also mitigated the chronic stress-induced impairment of hippocampal synaptic plasticity, in which both the LTP and depotentiation were significantly inhibited in stressed rats. Moreover, AMA enhanced the expression of hippocampal NR2B and PSD-95 in stressed rats. The data suggest that AMA may be an effective therapeutic agent for depression-like symptoms and associated cognitive disturbances.

  16. Aerobic exercise attenuates inhibitory avoidance memory deficit induced by paradoxical sleep deprivation in rats.

    Science.gov (United States)

    Fernandes, Jansen; Baliego, Luiz Guilherme Zaccaro; Peixinho-Pena, Luiz Fernando; de Almeida, Alexandre Aparecido; Venancio, Daniel Paulino; Scorza, Fulvio Alexandre; de Mello, Marco Tulio; Arida, Ricardo Mario

    2013-09-05

    The deleterious effects of paradoxical sleep deprivation (SD) on memory processes are well documented. Physical exercise improves many aspects of brain functions and induces neuroprotection. In the present study, we investigated the influence of 4 weeks of treadmill aerobic exercise on both long-term memory and the expression of synaptic proteins (GAP-43, synapsin I, synaptophysin, and PSD-95) in normal and sleep-deprived rats. Adult Wistar rats were subjected to 4 weeks of treadmill exercise training for 35 min, five times per week. Twenty-four hours after the last exercise session, the rats were sleep-deprived for 96 h using the modified multiple platform method. To assess memory after SD, all animals underwent training for the inhibitory avoidance task and were tested 24h later. The aerobic exercise attenuated the long-term memory deficit induced by 96 h of paradoxical SD. Western blot analysis of the hippocampus revealed increased levels of GAP-43 in exercised rats. However, the expression of synapsin I, synaptophysin, and PSD-95 was not modified by either exercise or SD. Our results suggest that an aerobic exercise program can attenuate the deleterious effects of SD on long-term memory and that this effect is not directly related to changes in the expression of the pre- and post-synaptic proteins analyzed in the study. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Myosin IXa binds AMPAR and regulates synaptic structure, LTP and cognitive function

    Directory of Open Access Journals (Sweden)

    Alessandra eFolci

    2016-01-01

    Full Text Available Myosin IXa (Myo9a is a motor protein that is highly expressed in the brain. However, the role of Myo9a in neurons remains unknown. Here, we investigated Myo9a function in hippocampal synapses. In rat hippocampal neurons, Myo9a localizes to the postsynaptic density (PSD and binds the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR GluA2 subunit. Myo9a+/- mice displayed a thicker PSD and increased levels of PSD95 and surface AMPAR expression. Furthermore, synaptic transmission, long-term potentiation (LTP and cognitive functions were impaired in Myo9a+/- mice. Together, these results support a key role for Myo9a in controlling the molecular structure and function of hippocampal synapses.

  18. Developmental Exposure to Cocaine Dynamically Dysregulates Cortical Arc/Arg3.1 Modulation in Response to a Challenge.

    Science.gov (United States)

    Caffino, Lucia; Giannotti, Giuseppe; Mottarlini, Francesca; Racagni, Giorgio; Fumagalli, Fabio

    2017-02-01

    During adolescence, the medial prefrontal cortex (mPFC) is still developing. We have previously shown that developmental cocaine exposure alters mPFC's ability to cope with challenging events. In this manuscript, we exposed rats developmentally treated with cocaine to a novelty task and analyzed the molecular changes of mPFC. Rats were exposed to cocaine from post-natal day (PND) 28 to PND 42 and sacrificed at PND 43, immediately after the novel object recognition (NOR) test. Cocaine-treated rats spent more time exploring the novel object than saline-treated counterparts, suggesting an increased response to novelty. The messenger RNA (mRNA) and protein levels of the immediate early gene Arc/Arg3.1 were reduced in both infralimbic (IL) and prelimbic (PL) cortices highlighting a baseline reduction of mPFC neuronal activity as a consequence of developmental exposure to cocaine. Intriguingly, significant molecular changes were observed in the IL, but not PL, cortex in response to the combination of cocaine exposure and test such as a marked upregulation of both Arc/Arg3.1 mRNA and protein levels only in cocaine-treated rats. As for proteins, such increase was observed only in the post-synaptic density and not in the whole homogenate, suggesting psychostimulant-induced changes in trafficking of Arc/Arg3.1 or an increased local translation. Notably, the same profile of Arc/Arg3.1 was observed for post-synaptic density (PSD)-95 leading to the possibility that Arc/Arg3.1 and PSD-95 bridge together to promote aberrant synaptic connectivity in IL cortex following repeated exposure to cocaine during brain development.

  19. miR-34a deficiency in APP/PS1 mice promotes cognitive function by increasing synaptic plasticity via AMPA and NMDA receptors.

    Science.gov (United States)

    Xu, Yuelong; Chen, Ping; Wang, Xianjun; Yao, Jinguo; Zhuang, Sujing

    2018-02-06

    MicroRNA (miR)-34a was recently determined to contribute to the pathological development of Alzheimer's disease (AD). miR-34a deficiency significantly attenuates cognitive deficits in amyloid precursor protein (APP)/presenilin 1 (PS1) mice; however, its role in early AD pathology and the underlying mechanisms remain elusive. Here, we confirmed that the increase of miR-34a expression in APP/PS1 mice was earlier than the relevant AD pathological characteristics, such as amyloid-β production, amyloid plaque deposition, and cognitive deficits. Furthermore, because predicted miR-34a target genes were broadly linked to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-d-aspartate (NMDA) receptors, we evaluated synaptic plasticity by investigating high-frequency conditioning tetanus-induced excitatory postsynaptic potential, which revealed that synaptic plasticity was promoted in miR-34a knockout/APP/PS1 mice. Therefore, we assessed the expression of the presynaptic components synaptophysin and postsynaptic density protein 95 (PSD95) and found that synaptophysin and PSD95 were not altered by miR-34a deficiency. Additionally, the synaptic strength (vesicular fusion, vesicular docking, and transporting) was either not significantly changed. We also evaluated the levels of AMPA and NMDA receptors, which showed that the expression of AMPA and NMDA receptors was markedly upregulated in APP/PS1 mice with miR-34a deficiency. We conclude that miR-34a is involved in synaptic deficits in AD pathological development, which was, at least in part, due to the inhibition of NMDA (by miR-34a-5p) and AMPA (by miR-34a-3p) receptor expression. Copyright © 2018. Published by Elsevier B.V.

  20. Structure-Function Relationship of Hydrophiidae Postsynaptic Neurotoxins

    Science.gov (United States)

    1992-03-11

    gland powder, and the resulting paste was ground (using a moctar and pestle ) for 40 min at 4 ’C. The paste was then suspended in approximately 600 ml...Singapore and the International Society on Toxinology, Singapore, Malaysia , p. 299. Kharin, V.E. (1984) Proc. Zool. Instit,. Leningrad 124: 128. Khole, V...Eds.) Venom and Toxin Research Group, National University of Singapore and the International Society on Toxinology, Singapore, Malaysia , p. 281

  1. Reverberation, Storage, and Postsynaptic Propagation of Memories during Sleep

    Science.gov (United States)

    Ribeiro, Sidarta; Nicolelis, Miguel A. L.

    2004-01-01

    In mammals and birds, long episodes of nondreaming sleep ("slow-wave" sleep, SW) are followed by short episodes of dreaming sleep ("rapid-eye-movement" sleep, REM). Both SW and REM sleep have been shown to be important for the consolidation of newly acquired memories, but the underlying mechanisms remain elusive. Here we review…

  2. Gephyrin-binding peptides visualize postsynaptic sites and modulate neurotransmission

    DEFF Research Database (Denmark)

    Maric, Hans Michael; Hausrat, Torben Johann; Neubert, Franziska

    2017-01-01

    γ-Aminobutyric acid type A and glycine receptors are the major mediators of fast synaptic inhibition in the human central nervous system and are established drug targets. However, all drugs targeting these receptors bind to the extracellular ligand-binding domain of the receptors, which inherentl...

  3. Reverberation, storage, and postsynaptic propagation of memories during sleep

    OpenAIRE

    Ribeiro, Sidarta; Nicolelis, Miguel A. L.

    2004-01-01

    In mammals and birds, long episodes of nondreaming sleep (“slow-wave” sleep, SW) are followed by short episodes of dreaming sleep (“rapid-eye-movement” sleep, REM). Both SW and REM sleep have been shown to be important for the consolidation of newly acquired memories, but the underlying mechanisms remain elusive. Here we review electrophysiological and molecular data suggesting that SW and REM sleep play distinct and complementary roles on memory consolidation: While postacquisition neuronal ...

  4. Glucagon-like peptide-1 excites firing and increases GABAergic miniature postsynaptic currents (mPSCs in gonadotropin-releasing hormone (GnRH neurons of the male mice via activation of nitric oxide (NO and suppression of endocannabinoid signaling pathways

    Directory of Open Access Journals (Sweden)

    Imre Farkas

    2016-09-01

    Full Text Available Glucagon-like peptide-1 (GLP-1, a metabolic signal molecule, regulates reproduction, although, the involved molecular mechanisms have not been elucidated, yet. Therefore, responsiveness of gonadotropin-releasing hormone (GnRH neurons to the GLP-1 analog Exendin-4 and elucidation of molecular pathways acting downstream to the GLP-1 receptor (GLP-1R have been challenged. Loose patch-clamp recordings revealed that Exendin-4 (100 nM–5 μM elevated firing rate in hypothalamic GnRH-GFP neurons of male mice via activation of GLP-1R. Whole-cell patch-clamp measurements demonstrated increased excitatory GABAergic miniature postsynaptic currents (mPSCs frequency after Exendin-4 administration, which was eliminated by the GLP-1R antagonist Exendin-3(9-39 (1 μM. Intracellular application of the G-protein inhibitor GDP-beta-S (2 mM impeded action of Exendin-4 on mPSCs, suggesting direct excitatory action of GLP-1 on GnRH neurons. Blockade of nitric-oxide (NO synthesis by L-NAME (100 μM or NPLA (1 μM or intracellular scavenging of NO by CPTIO (1 mM partially attenuated the excitatory effect of Exendin-4. Similar partial inhibition was achieved by hindering endocannabinoid pathway using CB1 inverse-agonist AM251 (1 μM. Simultaneous blockade of NO and endocannabinoid signaling mechanisms eliminated action of Exendin-4 suggesting involvement of both retrograde machineries. Intracellular application of the TRPV1-antagonist AMG9810 (10 μM or the FAAH-inhibitor PF3845 (5 μM impeded the GLP-1-triggered endocannabinoid pathway indicating an anandamide-TRPV1-sensitive control of 2-AG production. Furthermore, GLP-1 immunoreactive axons innervated GnRH neurons in the hypothalamus suggesting that GLP-1 of both peripheral and neuronal sources can modulate GnRH neurons. RT-qPCR study confirmed the expression of GLP-1R and nNOS mRNAs in GnRH-GFP neurons. Immuno-electron microscopic analysis revealed the presence of neuronal nitric oxide synthase (nNOS protein in Gn

  5. Diurnal rhythms in neurexins transcripts and inhibitory/excitatory synapse scaffold proteins in the biological clock.

    Science.gov (United States)

    Shapiro-Reznik, Mika; Jilg, Anje; Lerner, Hadas; Earnest, David J; Zisapel, Nava

    2012-01-01

    The neurexin genes (NRXN1/2/3) encode two families (α and β) of highly polymorphic presynaptic proteins that are involved in excitatory/inhibitory synaptic balance. Recent studies indicate that neuronal activation and memory formation affect NRXN1/2/3α expression and alternative splicing at splice sites 3 and 4 (SS#3/SS#4). Neurons in the biological clock residing in the suprachiasmatic nuclei of the hypothalamus (SCN) act as self-sustained oscillators, generating rhythms in gene expression and electrical activity, to entrain circadian bodily rhythms to the 24 hours day/night cycles. Cell autonomous oscillations in NRXN1/2/3α expression and SS#3/SS#4 exons splicing and their links to rhythms in excitatory/inhibitory synaptic balance in the circadian clock were explored. NRXN1/2/3α expression and SS#3/SS#4 splicing, levels of neurexin-2α and the synaptic scaffolding proteins PSD-95 and gephyrin (representing excitatory and inhibitory synapses, respectively) were studied in mRNA and protein extracts obtained from SCN of C3H/J mice at different times of the 24 hours day/night cycle. Further studies explored the circadian oscillations in these components and causality relationships in immortalized rat SCN2.2 cells. Diurnal rhythms in mNRXN1α and mNRXN2α transcription, SS#3/SS#4 exon-inclusion and PSD-95 gephyrin and neurexin-2α levels were found in the SCN in vivo. No such rhythms were found with mNRXN3α. SCN2.2 cells also exhibited autonomous circadian rhythms in rNRXN1/2 expression SS#3/SS#4 exon inclusion and PSD-95, gephyrin and neurexin-2α levels. rNRXN3α and rNRXN1/2β were not expressed. Causal relationships were demonstrated, by use of specific siRNAs, between rNRXN2α SS#3 exon included transcripts and gephyrin levels in the SCN2.2 cells. These results show for the first time dynamic, cell autonomous, diurnal rhythms in expression and splicing of NRXN1/2 and subsequent effects on the expression of neurexin-2α and postsynaptic scaffolding proteins

  6. Perinatal exposure to lead (Pb) induces ultrastructural and molecular alterations in synapses of rat offspring.

    Science.gov (United States)

    Gąssowska, Magdalena; Baranowska-Bosiacka, Irena; Moczydłowska, Joanna; Frontczak-Baniewicz, Małgorzata; Gewartowska, Magdalena; Strużyńska, Lidia; Gutowska, Izabela; Chlubek, Dariusz; Adamczyk, Agata

    2016-12-12

    Lead (Pb), environmentally abundant heavy-metal pollutant, is a strong toxicant for the developing central nervous system. Pb intoxication in children, even at low doses, is found to affect learning and memorizing, with devastating effects on cognitive function and intellectual development. However, the precise mechanism by which Pb impairs synaptic plasticity is not fully elucidated. The purpose of this study was to investigate the effect of pre- and neonatal exposure to low dose of Pb (with Pb concentrations in whole blood below 10μg/dL) on the synaptic structure and the pre- and postsynaptic proteins expression in the developing rat brain. Furthermore, the level of brain-derived neurotrophic factor (BDNF) was analyzed. Pregnant female Wistar rats received 0.1% lead acetate (PbAc) in drinking water from the first day of gestation until weaning of the offspring, while the control animals received drinking water. During the feeding of pups, mothers from the Pb-group were continuously receiving PbAc. Pups of both groups were weaned at postnatal day 21 and then until postnatal day 28 received only drinking water. 28-day old pups were sacrificed and the ultrastructural changes as well as expression of presynaptic (VAMP1/2, synaptophysin, synaptotagmin-1, SNAP25, syntaxin-1) and postsynaptic (PSD-95) proteins were analyzed in: forebrain cortex, cerebellum and hippocampus. Our data revealed that pre- and neonatal exposure to low dose of Pb promotes pathological changes in synapses, including nerve endings swelling, blurred and thickened synaptic cleft structure as well as enhanced density of synaptic vesicles in the presynaptic area. Moreover, synaptic mitochondria were elongated, swollen or shrunken in Pb-treated animals. These structural abnormalities were accompanied by decrease in the level of key synaptic proteins: synaptotagmin-1 in cerebellum, SNAP25 in hippocampus and syntaxin-1 in cerebellum and hippocampus. In turn, increased level of synaptophysin was

  7. Several adaptor proteins promote intracellular localisation of the transporter MRP4/ABCC4 in platelets and haematopoietic cells.

    Science.gov (United States)

    Schaletzki, Yvonne; Kromrey, Marie-Luise; Bröderdorf, Susanne; Hammer, Elke; Grube, Markus; Hagen, Paul; Sucic, Sonja; Freissmuth, Michael; Völker, Uwe; Greinacher, Andreas; Rauch, Bernhard H; Kroemer, Heyo K; Jedlitschky, Gabriele

    2017-01-05

    The multidrug resistance protein 4 (MRP4/ABCC4) has been identified as an important transporter for signalling molecules including cyclic nucleotides and several lipid mediators in platelets and may thus represent a novel target to interfere with platelet function. Besides its localisation in the plasma membrane, MRP4 has been also detected in the membrane of dense granules in resting platelets. In polarised cells it is localised at the basolateral or apical plasma membrane. To date, the mechanism of MRP4 trafficking has not been elucidated; protein interactions may regulate both the localisation and function of this transporter. We approached this issue by searching for interacting proteins by in vitro binding assays, followed by immunoblotting and mass spectrometry, and by visualising their co-localisation in platelets and haematopoietic cells. We identified the PDZ domain containing scaffold proteins ezrin-binding protein 50 (EBP50/NHERF1), postsynaptic density protein 95 (PSD95), and sorting nexin 27 (SNX27), but also the adaptor protein complex 3 subunit β3A (AP3B1) and the heat shock protein HSP90 as putative interaction partners of MRP4. The knock-down of SNX27, PSD95, and AP3B1 by siRNA in megakaryoblastic leukaemia cells led to a redistribution of MRP4 from intracellular structures to the plasma membrane. Inhibition of HSP90 led to a diminished expression and retention of MRP4 in the endoplasmic reticulum. These results indicate that MRP4 localisation and function are regulated by multiple protein interactions. Changes in the adaptor proteins can hence lead to altered localisation and function of the transporter.

  8. Effects of exercise intensity on spatial memory performance and hippocampal synaptic plasticity in transient brain ischemic rats.

    Science.gov (United States)

    Shih, Pei-Cheng; Yang, Yea-Ru; Wang, Ray-Yau

    2013-01-01

    Memory impairment is commonly noted in stroke survivors, and can lead to delay of functional recovery. Exercise has been proved to improve memory in adult healthy subjects. Such beneficial effects are often suggested to relate to hippocampal synaptic plasticity, which is important for memory processing. Previous evidence showed that in normal rats, low intensity exercise can improve synaptic plasticity better than high intensity exercise. However, the effects of exercise intensities on hippocampal synaptic plasticity and spatial memory after brain ischemia remain unclear. In this study, we investigated such effects in brain ischemic rats. The middle cerebral artery occlusion (MCAO) procedure was used to induce brain ischemia. After the MCAO procedure, rats were randomly assigned to sedentary (Sed), low-intensity exercise (Low-Ex), or high-intensity exercise (High-Ex) group. Treadmill training began from the second day post MCAO procedure, 30 min/day for 14 consecutive days for the exercise groups. The Low-Ex group was trained at the speed of 8 m/min, while the High-Ex group at the speed of 20 m/min. The spatial memory, hippocampal brain-derived neurotrophic factor (BDNF), synapsin-I, postsynaptic density protein 95 (PSD-95), and dendritic structures were examined to document the effects. Serum corticosterone level was also quantified as stress marker. Our results showed the Low-Ex group, but not the High-Ex group, demonstrated better spatial memory performance than the Sed group. Dendritic complexity and the levels of BDNF and PSD-95 increased significantly only in the Low-Ex group as compared with the Sed group in bilateral hippocampus. Notably, increased level of corticosterone was found in the High-Ex group, implicating higher stress response. In conclusion, after brain ischemia, low intensity exercise may result in better synaptic plasticity and spatial memory performance than high intensity exercise; therefore, the intensity is suggested to be considered

  9. Effects of exercise intensity on spatial memory performance and hippocampal synaptic plasticity in transient brain ischemic rats.

    Directory of Open Access Journals (Sweden)

    Pei-Cheng Shih

    Full Text Available Memory impairment is commonly noted in stroke survivors, and can lead to delay of functional recovery. Exercise has been proved to improve memory in adult healthy subjects. Such beneficial effects are often suggested to relate to hippocampal synaptic plasticity, which is important for memory processing. Previous evidence showed that in normal rats, low intensity exercise can improve synaptic plasticity better than high intensity exercise. However, the effects of exercise intensities on hippocampal synaptic plasticity and spatial memory after brain ischemia remain unclear. In this study, we investigated such effects in brain ischemic rats. The middle cerebral artery occlusion (MCAO procedure was used to induce brain ischemia. After the MCAO procedure, rats were randomly assigned to sedentary (Sed, low-intensity exercise (Low-Ex, or high-intensity exercise (High-Ex group. Treadmill training began from the second day post MCAO procedure, 30 min/day for 14 consecutive days for the exercise groups. The Low-Ex group was trained at the speed of 8 m/min, while the High-Ex group at the speed of 20 m/min. The spatial memory, hippocampal brain-derived neurotrophic factor (BDNF, synapsin-I, postsynaptic density protein 95 (PSD-95, and dendritic structures were examined to document the effects. Serum corticosterone level was also quantified as stress marker. Our results showed the Low-Ex group, but not the High-Ex group, demonstrated better spatial memory performance than the Sed group. Dendritic complexity and the levels of BDNF and PSD-95 increased significantly only in the Low-Ex group as compared with the Sed group in bilateral hippocampus. Notably, increased level of corticosterone was found in the High-Ex group, implicating higher stress response. In conclusion, after brain ischemia, low intensity exercise may result in better synaptic plasticity and spatial memory performance than high intensity exercise; therefore, the intensity is suggested to be

  10. Copper: From neurotransmission to neuroproteostasis

    Directory of Open Access Journals (Sweden)

    Carlos M Opazo

    2014-07-01

    Full Text Available Copper is critical for the Central Nervous System (CNS development and function. In particular, different studies have shown the effect of copper at brain synapses, where it inhibits Long Term Potentation (LTP and receptor pharmacology. Paradoxically, according to recent studies copper is required for a normal LTP response. Copper is released at the synaptic cleft, where it blocks glutamate receptors, which explain its blocking effects on excitatory neurotransmission. Our results indicate that copper also enhances neurotransmission through the accumulation of PSD95 protein, which increase the levels of AMPA receptors located at the plasma membrane of the post-synaptic density. Thus, our findings represent a novel mechanism for the action of copper, which may have implications for the neurophysiology and neuropathology of the CNS. These data indicate that synaptic configuration is sensitive to transient changes in transition metal homeostasis. Our results suggest that copper increases GluA1 subunit levels of the AMPA receptor through the anchorage of AMPA receptors to the plasma membrane as a result of PSD-95 accumulation. Here, we will review the role of copper on neurotransmission of CNS neurons. In addition, we will discuss the potential mechanisms by which copper could modulate neuronal proteostasis (neuroproteostasis in the CNS with focus in the Ubiquitin Proteasome System, which is particularly relevant to neurological disorders such Alzheimer’s disease (AD where copper and protein dyshomeostasis may contribute to neurodegeneration. An understanding of these mechanisms may ultimately lead to the development of novel therapeutic approaches to control metal and synaptic alterations observed in AD patients.

  11. Neuronal expression of sodium/bicarbonate cotransporter NBCn1 (SLC4A7) and its response to chronic metabolic acidosis

    Science.gov (United States)

    Park, Hae Jeong; Rajbhandari, Ira; Yang, Han Soo; Lee, Soojung; Cucoranu, Delia; Cooper, Deborah S.; Klein, Janet D.; Sands, Jeff M.

    2010-01-01

    The sodium-bicarbonate cotransporter NBCn1 (SLC4A7) is an acid-base transporter that normally moves Na+ and HCO3− into the cell. This membrane protein is sensitive to cellular and systemic pH changes. We examined NBCn1 expression and localization in the brain and its response to chronic metabolic acidosis. Two new NBCn1 antibodies were generated by immunizing a rabbit and a guinea pig. The antibodies stained neurons in a variety of rat brain regions, including hippocampal pyramidal neurons, dentate gyrus granular neurons, posterior cortical neurons, and cerebellar Purkinje neurons. Choroid plexus epithelia were also stained. Double immunofluorescence labeling showed that NBCn1 and the postsynaptic density protein PSD-95 were found in the same hippocampal CA3 neurons and partially colocalized in dendrites. PSD-95 was pulled down from rat brain lysates with the GST/NBCn1 fusion protein and was also coimmunoprecipitated with NBCn1. Chronic metabolic acidosis was induced by feeding rats with normal chow or 0.4 M HCl-containing chow for 7 days. Real-time PCR and immunoblot showed upregulation of NBCn1 mRNA and protein in the hippocampus of acidotic rats. NBCn1 immunostaining was enhanced in CA3 neurons, posterior cortical neurons, and cerebellar granular cells. Intraperitoneal administration of N-methyl-d-aspartate caused neuronal death determined by caspase-3 activity, and this effect was more severe in acidotic rats. Administering N-methyl-d-aspartate also inhibited NBCn1 upregulation in acidotic rats. We conclude that NBCn1 in neurons is upregulated by chronic acid loads, and this upregulation is associated with glutamate excitotoxicity. PMID:20147654

  12. Rapid glutamate receptor 2 trafficking during retinal degeneration

    Directory of Open Access Journals (Sweden)

    Lin Yanhua

    2012-02-01

    Full Text Available Abstract Background Retinal degenerations, such as age-related macular degeneration (AMD and retinitis pigmentosa (RP, are characterized by photoreceptor loss and anomalous remodeling of the surviving retina that corrupts visual processing and poses a barrier to late-stage therapeutic interventions in particular. However, the molecular events associated with retinal remodeling remain largely unknown. Given our prior evidence of ionotropic glutamate receptor (iGluR reprogramming in retinal degenerations, we hypothesized that the edited glutamate receptor 2 (GluR2 subunit and its trafficking may be modulated in retinal degenerations. Results Adult albino Balb/C mice were exposed to intense light for 24 h to induce light-induced retinal degeneration (LIRD. We found that prior to the onset of photoreceptor loss, protein levels of GluR2 and related trafficking proteins, including glutamate receptor-interacting protein 1 (GRIP1 and postsynaptic density protein 95 (PSD-95, were rapidly increased. LIRD triggered neuritogenesis in photoreceptor survival regions, where GluR2 and its trafficking proteins were expressed in the anomalous dendrites. Immunoprecipitation analysis showed interaction between KIF3A and GRIP1 as well as PSD-95, suggesting that KIF3A may mediate transport of GluR2 and its trafficking proteins to the novel dendrites. However, in areas of photoreceptor loss, GluR2 along with its trafficking proteins nearly vanished in retracted retinal neurites. Conclusions All together, LIRD rapidly triggers GluR2 plasticity, which is a potential mechanism behind functionally phenotypic revisions of retinal neurons and neuritogenesis during retinal degenerations.

  13. Role of sigma 1 receptor in high fat diet-induced peripheral neuropathy.

    Science.gov (United States)

    Song, Tieying; Zhao, Jianhui; Ma, Xiaojing; Zhang, Zaiwang; Jiang, Bo; Yang, Yunliang

    2017-09-26

    The neurobiological mechanisms of obesity-induced peripheral neuropathy are poorly understood. We evaluated the role of Sigma-1 receptor (Sig-1R) and NMDA receptor (NMDARs) in the spinal cord in peripheral neuropathy using an animal model of high fat diet-induced diabetes. We examined the expression of Sig-1R and NMDAR subunits GluN2A and GluN2B along with postsynaptic density protein 95 (PSD-95) in the spinal cord after 24-week HFD treatment in both wild-type and Sig-1R-/- mice. Finally, we examined the effects of repeated intrathecal administrations of selective Sig-1R antagonists BD1047 in HFD-fed wild-type mice on peripheral neuropathy. Wild-type mice developed tactile allodynia and thermal hypoalgesia after 24-week HFD treatment. HFD-induced peripheral neuropathy correlated with increased expression of GluN2A and GluN2B subunits of NMDARs, PDS-95, and Sig-1R, as well as increased Sig-1R-NMDAR interaction in the spinal cord. In contrast, Sig-1R-/- mice did not develop thermal hypoalgesia or tactile allodynia after 24-week HFD treatment, and the levels of GluN2A, GluN2B, and PSD-95 were not altered in the spinal cord of HFD-fed Sig-1R-/- mice. Finally, repeated intrathecal administrations of selective Sig-1R antagonists BD1047 in HFD-fed wild-type mice attenuated peripheral neuropathy. Our results suggest that obesity-associated peripheral neuropathy may involve Sig-1R-mediated enhancement of NMDAR expression in the spinal cord.

  14. Positioning of AMPA Receptor-Containing Endosomes Regulates Synapse Architecture

    Directory of Open Access Journals (Sweden)

    Marta Esteves da Silva

    2015-11-01

    Full Text Available Lateral diffusion in the membrane and endosomal trafficking both contribute to the addition and removal of AMPA receptors (AMPARs at postsynaptic sites. However, the spatial coordination between these mechanisms has remained unclear, because little is known about the dynamics of AMPAR-containing endosomes. In addition, how the positioning of AMPAR-containing endosomes affects synapse organization and functioning has never been directly explored. Here, we used live-cell imaging in hippocampal neuron cultures to show that intracellular AMPARs are transported in Rab11-positive recycling endosomes, which frequently enter dendritic spines and depend on the microtubule and actin cytoskeleton. By using chemically induced dimerization systems to recruit kinesin (KIF1C or myosin (MyosinV/VI motors to Rab11-positive recycling endosomes, we controlled their trafficking and found that induced removal of recycling endosomes from spines decreases surface AMPAR expression and PSD-95 clusters at synapses. Our data suggest a mechanistic link between endosome positioning and postsynaptic structure and composition.

  15. New players tip the scales in the balance between excitatory and inhibitory synapses

    Directory of Open Access Journals (Sweden)

    El-Husseini Alaa

    2005-03-01

    Full Text Available Abstract Synaptogenesis is a highly controlled process, involving a vast array of players which include cell adhesion molecules, scaffolding and signaling proteins, neurotransmitter receptors and proteins associated with the synaptic vesicle machinery. These molecules cooperate in an intricate manner on both the pre- and postsynaptic sides to orchestrate the precise assembly of neuronal contacts. This is an amazing feat considering that a single neuron receives tens of thousands of synaptic inputs but virtually no mismatch between pre- and postsynaptic components occur in vivo. One crucial aspect of synapse formation is whether a nascent synapse will develop into an excitatory or inhibitory contact. The tight control of a balance between the types of synapses formed regulates the overall neuronal excitability, and is thus critical for normal brain function and plasticity. However, little is known about how this balance is achieved. This review discusses recent findings which provide clues to how neurons may control excitatory and inhibitory synapse formation, with focus on the involvement of the neuroligin family and PSD-95 in this process.

  16. Dose-dependent changes in neuroinflammatory and arachidonic acid cascade markers with synaptic marker loss in rat lipopolysaccharide infusion model of neuroinflammation

    Directory of Open Access Journals (Sweden)

    Kellom Matthew

    2012-05-01

    Full Text Available Abstract Background Neuroinflammation, caused by six days of intracerebroventricular infusion of bacterial lipopolysaccharide (LPS, stimulates rat brain arachidonic acid (AA metabolism. The molecular changes associated with increased AA metabolism are not clear. We examined effects of a six-day infusion of a low-dose (0.5 ng/h and a high-dose (250 ng/h of LPS on neuroinflammatory, AA cascade, and pre- and post-synaptic markers in rat brain. We used artificial cerebrospinal fluid-infused brains as controls. Results Infusion of low- or high-dose LPS increased brain protein levels of TNFα, and iNOS, without significantly changing GFAP. High-dose LPS infusion upregulated brain protein and mRNA levels of AA cascade markers (cytosolic cPLA2-IVA, secretory sPLA2-V, cyclooxygenase-2 and 5-lipoxygenase, and of transcription factor NF-κB p50 DNA binding activity. Both LPS doses increased cPLA2 and p38 mitogen-activated protein kinase levels, while reducing protein levels of the pre-synaptic marker, synaptophysin. Post-synaptic markers drebrin and PSD95 protein levels were decreased with high- but not low-dose LPS. Conclusions Chronic LPS infusion has differential effects, depending on dose, on inflammatory, AA and synaptic markers in rat brain. Neuroinflammation associated with upregulated brain AA metabolism can lead to synaptic dysfunction.

  17. Estrogen Modulates ubc9 Expression and Synaptic Redistribution in the Brain of APP/PS1 Mice and Cortical Neurons.

    Science.gov (United States)

    Lai, Yu-Jie; Liu, Lu; Hu, Xiao-Tong; He, Ling; Chen, Guo-Jun

    2017-03-01

    Estrogen exerts multiple actions in the brain and is an important neuroprotective factor in a number of neuronal disorders. However, the underlying mechanism remains unknown. Studies demonstrate that ubiquitin-conjugating enzyme 9 (ubc9) has an integral role in synaptic plasticity and may contribute to the pathology of neuronal disorders. We aimed to investigate the effects of estrogen on ubc9 and in the Alzheimer's disease brain. Ubc9 protein and mRNA were significantly increased in the cortex and hippocampus of APP/PS1 mice with enhanced SUMOylation. Systemic estrogen administration led to reduced ubc9 expression in ovariectomized APP/PS1 mice and reduced SUMOylation. The inhibition of ubc9 expression by estrogen was found to be dose-dependent in cultured neurons. However, estrogen receptor (ER) antagonist ICI182780 did not block the inhibition of ubc9 expression by estrogen. Furthermore, the reduced expression of ubc9 was not mediated by ERα or ERβ agonists alone or in combination, but by the membrane-impermeable ER agonist E2-bovine serum albumin. The activation of the G protein-coupled ER mediated the inhibition of ubc9 expression of estrogen. A phosphoinositide 3-kinase (PI3K) inhibitor, rather than an extracellular signal-regulated kinase inhibitor, blocked the inhibition of ubc9 by estrogen. Estrogen treatment significantly increased the phosphorylation of PI3K, which suggests that activation of the PI3K pathway by estrogen is required for ubc9 regulation. Further, ubc9 interacted with the synaptic proteins post-synaptic density protein 95 (PSD95) and synaptophysin. Estrogen decreased the interaction of ubc9 with post-synaptic PSD95, but increased the interaction of ubc9 with pre-synaptic synaptophysin. These results suggest that a membrane-bound ER might mediate the estrogen inhibition of ubc9 in cortical neurons, where PI3K plays an important role. We also show that ubc9 can interact with synaptic proteins, which are subject to estrogen regulation.

  18. Distinct Localization of SNAP47 Protein in GABAergic and Glutamatergic Neurons in the Mouse and the Rat Hippocampus.

    Science.gov (United States)

    Münster-Wandowski, Agnieszka; Heilmann, Heike; Bolduan, Felix; Trimbuch, Thorsten; Yanagawa, Yuchio; Vida, Imre

    2017-01-01

    Synaptosomal-associated protein of 47 kDa (SNAP47) isoform is an atypical member of the SNAP family, which does not contribute directly to exocytosis and synaptic vesicle (SV) recycling. Initial characterization of SNAP47 revealed a widespread expression in nervous tissue, but little is known about its cellular and subcellular localization in hippocampal neurons. Therefore, in the present study we applied multiple-immunofluorescence labeling, immuno-electron microscopy and in situ hybridization (ISH) and analyzed the localization of SNAP47 in pre- and postsynaptic compartments of glutamatergic and GABAergic neurons in the mouse and rat hippocampus. While the immunofluorescence signal for SNAP47 showed a widespread distribution in both mouse and rat, the labeling pattern was complementary in the two species: in the mouse the immunolabeling was higher over the CA3 stratum radiatum, oriens and cell body layer. In contrast, in the rat the labeling was stronger over the CA1 neuropil and in the CA3 stratum lucidum. Furthermore, in the mouse high somatic labeling for SNAP47 was observed in GABAergic interneurons (INs). On the contrary, in the rat, while most INs were positive, they blended in with the high neuropil labeling. ISH confirmed the high expression of SNAP47 RNA in INs in the mouse. Co-staining for SNAP47 and pre- and postsynaptic markers in the rat revealed a strong co-localization postsynaptically with PSD95 in dendritic spines of pyramidal cells and, to a lesser extent, presynaptically, with ZnT3 and vesicular glutamate transporter 1 (VGLUT1) in glutamatergic terminals such as mossy fiber (MF) boutons. Ultrastructural analysis confirmed the pre- and postsynaptic localization at glutamatergic synapses. Furthermore, in the mouse hippocampus SNAP47 was found to be localized at low levels to dendritic shafts and axon terminals of putative INs forming symmetric synapses, indicating that this protein could be trafficked to both post- and presynaptic sites in both

  19. Effects of Fluoxetine and Visual Experience on Glutamatergic and GABAergic Synaptic Proteins in Adult Rat Visual Cortex123

    Science.gov (United States)

    Beshara, Simon; Beston, Brett R.; Pinto, Joshua G. A.

    2015-01-01

    Abstract Fluoxetine has emerged as a novel treatment for persistent amblyopia because in adult animals it reinstates critical period-like ocular dominance plasticity and promotes recovery of visual acuity. Translation of these results from animal models to the clinic, however, has been challenging because of the lack of understanding of how this selective serotonin reuptake inhibitor affects glutamatergic and GABAergic synaptic mechanisms that are essential for experience-dependent plasticity. An appealing hypothesis is that fluoxetine recreates a critical period (CP)-like state by shifting synaptic mechanisms to be more juvenile. To test this we studied the effect of fluoxetine treatment in adult rats, alone or in combination with visual deprivation [monocular deprivation (MD)], on a set of highly conserved presynaptic and postsynaptic proteins (synapsin, synaptophysin, VGLUT1, VGAT, PSD-95, gephyrin, GluN1, GluA2, GluN2B, GluN2A, GABAAα1, GABAAα3). We did not find evidence that fluoxetine shifted the protein amounts or balances to a CP-like state. Instead, it drove the balances in favor of the more mature subunits (GluN2A, GABAAα1). In addition, when fluoxetine was paired with MD it created a neuroprotective-like environment by normalizing the glutamatergic gain found in adult MDs. Together, our results suggest that fluoxetine treatment creates a novel synaptic environment dominated by GluN2A- and GABAAα1-dependent plasticity. PMID:26730408

  20. Tau deposition drives neuropathological, inflammatory and behavioral abnormalities independently of neuronal loss in a novel mouse model

    Science.gov (United States)

    Cook, Casey; Kang, Silvia S.; Carlomagno, Yari; Lin, Wen-Lang; Yue, Mei; Kurti, Aishe; Shinohara, Mitsuru; Jansen-West, Karen; Perkerson, Emilie; Castanedes-Casey, Monica; Rousseau, Linda; Phillips, Virginia; Bu, Guojun; Dickson, Dennis W.; Petrucelli, Leonard; Fryer, John D.

    2015-01-01

    Aberrant tau protein accumulation drives neurofibrillary tangle (NFT) formation in several neurodegenerative diseases. Currently, efforts to elucidate pathogenic mechanisms and assess the efficacy of therapeutic targets are limited by constraints of existing models of tauopathy. In order to generate a more versatile mouse model of tauopathy, somatic brain transgenesis was utilized to deliver adeno-associated virus serotype 1 (AAV1) encoding human mutant P301L-tau compared with GFP control. At 6 months of age, we observed widespread human tau expression with concomitant accumulation of hyperphosphorylated and abnormally folded proteinase K resistant tau. However, no overt neuronal loss was observed, though significant abnormalities were noted in the postsynaptic scaffolding protein PSD95. Neurofibrillary pathology was also detected with Gallyas silver stain and Thioflavin-S, and electron microscopy revealed the deposition of closely packed filaments. In addition to classic markers of tauopathy, significant neuroinflammation and extensive gliosis were detected in AAV1-TauP301L mice. This model also recapitulates the behavioral phenotype characteristic of mouse models of tauopathy, including abnormalities in exploration, anxiety, and learning and memory. These findings indicate that biochemical and neuropathological hallmarks of tauopathies are accurately conserved and are independent of cell death in this novel AAV-based model of tauopathy, which offers exceptional versatility and speed in comparison with existing transgenic models. Therefore, we anticipate this approach will facilitate the identification and validation of genetic modifiers of disease, as well as accelerate preclinical assessment of potential therapeutic targets. PMID:26276810

  1. Generation and characterization of conditional heparin-binding EGF-like growth factor knockout mice.

    Directory of Open Access Journals (Sweden)

    Atsushi Oyagi

    Full Text Available Recently, neurotrophic factors and cytokines have been shown to be associated in psychiatric disorders, such as schizophrenia, bipolar disorder, and depression. Heparin-binding epidermal growth factor-like growth factor (HB-EGF is a member of the EGF family, serves as a neurotrophic molecular and plays a significant role in the brain. We generated mice in which HB-EGF activity is disrupted specifically in the ventral forebrain. These knockout mice showed (a behavioral abnormalities similar to those described in psychiatric disorders, which were ameliorated by typical or atypical antipsychotics, (b altered dopamine and serotonin levels in the brain, (c decreases in spine density in neurons of the prefrontal cortex, (d reductions in the protein levels of the NR1 subunit of the N-methyl-D-aspartate (NMDA receptor and post-synaptic protein-95 (PSD-95, (e decreases in the EGF receptor, and in the calcium/calmodulin-dependent protein kinase II (CaMK II signal cascade. These results suggest the alterations affecting HB-EGF signaling could comprise a contributing factor in psychiatric disorder.

  2. Electro-acupuncture ameliorates cognitive impairment via improvement of brain-derived neurotropic factor-mediated hippocampal synaptic plasticity in cerebral ischemia-reperfusion injured rats.

    Science.gov (United States)

    Lin, Ruhui; Li, Xiaojie; Liu, Weilin; Chen, Wenlie; Yu, Kunqiang; Zhao, Congkuai; Huang, Jia; Yang, Shanli; Peng, Hongwei; Tao, Jing; Chen, Lidian

    2017-09-01

    A previous study by our group found that electro-acupuncture (EA) at the Shenting (DU24) and Baihui (DU20) acupoints ameliorates cognitive impairment in rats with cerebral ischemia-reperfusion (I/R) injury. However, the precise mechanism of action has remained largely unknown. The present study investigated whether brain-derived neurotropic factor (BDNF) mediates hippocampal synaptic plasticity as the underlying mechanism. Rats were randomly divided into three groups: The sham operation control (Sham) group, the focal cerebral ischemia-reperfusion (I/R) group, and the I/R with EA treatment (I/R+EA) group. The I/R+EA group received EA treatment at the Shenting (DU24) and Baihui (DU20) acupoints after the operation. EA treatment was found to ameliorate neurological deficits (Psynaptic plasticity. Simultaneously, EA increased the hippocampal expression of BDNF, its high-affinity tropomyosin receptor kinase B (TrkB) and post-synaptic density protein-95 (PSD-95) in the rats with cerebral I/R injury. Collectively, the findings suggested that BDNF-mediated hippocampal synaptic plasticity may be one mechanism via which EA treatment at the Shenting (DU24) and Baihui (DU20) acupoints improves cognitive function in cerebral I/R injured rats.

  3. Activity-dependent expression of miR-132 regulates immediate-early gene induction during olfactory learning in the greater short-nosed fruit bat, Cynopterus sphinx.

    Science.gov (United States)

    Mukilan, Murugan; Ragu Varman, Durairaj; Sudhakar, Sivasubramaniam; Rajan, Koilmani Emmanuvel

    2015-04-01

    The activity-dependent expression of immediate-early genes (IEGs) and microRNA (miR)-132 has been implicated in synaptic plasticity and the formation of long-term memory (LTM). In the present study, we show that olfactory training induces the expression of IEGs (EGR-1, C-fos, C-jun) and miR-132 at similar time scale in olfactory bulb (OB) of Cynopterus sphinx. We examined the role of miR-132 in the OB using antisense oligodeoxynucleotide (AS-ODN) and demonstrated that a local infusion of AS-ODN in the OB 2h prior to training impaired olfactory memory formation in C. sphinx. However, the infusion of AS-ODN post-training did not cause a deficit in memory formation. Furthermore, the inhibition of miR-132 reduced the olfactory training-induced expression of IEGs and post synaptic density protein-95 (PSD-95) in the OB. Additionally, we show that miR-132 regulates the activation of calcium/calmodulin-dependent protein kinase-II (CaMKII) and cAMP response element binding protein (CREB), possibly through miR-148a. These data suggest that olfactory training induces the expression of miR-132 and IEGs, which in turn activates post-synaptic proteins that regulate olfactory memory formation. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. What happens to your brain on the way to Mars.

    Science.gov (United States)

    Parihar, Vipan K; Allen, Barrett; Tran, Katherine K; Macaraeg, Trisha G; Chu, Esther M; Kwok, Stephanie F; Chmielewski, Nicole N; Craver, Brianna M; Baulch, Janet E; Acharya, Munjal M; Cucinotta, Francis A; Limoli, Charles L

    2015-05-01

    As NASA prepares for the first manned spaceflight to Mars, questions have surfaced concerning the potential for increased risks associated with exposure to the spectrum of highly energetic nuclei that comprise galactic cosmic rays. Animal models have revealed an unexpected sensitivity of mature neurons in the brain to charged particles found in space. Astronaut autonomy during long-term space travel is particularly critical as is the need to properly manage planned and unanticipated events, activities that could be compromised by accumulating particle traversals through the brain. Using mice subjected to space-relevant fluences of charged particles, we show significant cortical- and hippocampal-based performance decrements 6 weeks after acute exposure. Animals manifesting cognitive decrements exhibited marked and persistent radiation-induced reductions in dendritic complexity and spine density along medial prefrontal cortical neurons known to mediate neurotransmission specifically interrogated by our behavioral tasks. Significant increases in postsynaptic density protein 95 (PSD-95) revealed major radiation-induced alterations in synaptic integrity. Impaired behavioral performance of individual animals correlated significantly with reduced spine density and trended with increased synaptic puncta, thereby providing quantitative measures of risk for developing cognitive decrements. Our data indicate an unexpected and unique susceptibility of the central nervous system to space radiation exposure, and argue that the underlying radiation sensitivity of delicate neuronal structure may well predispose astronauts to unintended mission-critical performance decrements and/or longer-term neurocognitive sequelae.

  5. Vamping: stereology-based automated quantification of fluorescent puncta size and density.

    Science.gov (United States)

    Dumitriu, Dani; Berger, Seth I; Hamo, Carine; Hara, Yuko; Bailey, Megan; Hamo, Amarelle; Grossman, Yael S; Janssen, William G; Morrison, John H

    2012-07-30

    The size of dendritic spines and postsynaptic densities (PSDs) is well known to be correlated with molecular and functional characteristics of the synapse. Thus, the development of microscopy methods that allow high throughput quantification and measurement of PSDs is a contemporary need in the field of neurobiology. While the gold standard for measurement of sub-micrometer structures remains electron microscopy (EM), this method is exceedingly laborious and therefore not always feasible. Immunohistochemistry (IHC) is a much faster technique for identifying biological structures such as PSDs, but the fluorescent images resulting from it have traditionally been harder to interpret and quantify. Here, we report on two new image analysis tools that result in accurate size and density measurements of fluorescent puncta. Anti-PSD-95 staining was used to target synapses. The new technique of vamping, using Volume Assisted Measurement of Puncta in 2 and 3 Dimensions (VAMP2D and VAMP3D) respectively, is based on stereological principles. The fully automated image analysis tool was tested on the same subjects for whom we had previously obtained EM measurements of PSD size and/or density. Based on highly consistent results between data obtained by each of these methods, vamping offers an expedient alternative to EM that can nonetheless deliver a high level of accuracy in measuring sub-cellular structures. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. The NMDAR subunit NR3A interacts with microtubule-associated protein 1S in the brain

    DEFF Research Database (Denmark)

    Eriksson, Maria; Samuelsson, Helena; Samuelsson, Eva-Britt

    2007-01-01

    -proximal part of the NR3A C-terminus. MAP1S belongs to the same family as MAP1A and MAP1B, and was found to be abundant in both postnatal and adult rat brain. In hippocampal neurons the distribution-pattern of MAP1S resembled that of beta-tubulin III, but a fraction of the protein colocalized with synaptic...... markers synapsin and postsynaptic density protein 95 (PSD95), in beta-tubulin III-negative filopodia-like protrusions. There was coexistance between MAP1S and NR3A immunoreactivity in neurite shafts and occasionally in filopodia-like processes. MAP1S potentially links NR3A to the cytoskeleton, and may......When screening a brain cDNA library, we found that the N-methyl-D-aspartate receptor subunit NR3A binds to microtubule-associated protein (MAP) 1S/chromosome 19 open reading frame 5 (C19ORF5). The interaction was confirmed in vitro and in vivo, and binding of MAP1S was localized to the membrane...

  7. Long-term atorvastatin treatment leads to alterations in behavior, cognition, and hippocampal biochemistry.

    Science.gov (United States)

    Schilling, Jan M; Cui, Weihua; Godoy, Joseph C; Risbrough, Victoria B; Niesman, Ingrid R; Roth, David M; Patel, Piyush M; Drummond, John C; Patel, Hemal H; Zemljic-Harpf, Alice E; Head, Brian P

    2014-07-01

    Membrane/lipid rafts (MLR) are plasmalemmal microdomains that are essential for neuronal signaling and synaptic development/stabilization. Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in the biosynthesis of mevalonic, a precursor to cholesterol via the mevalonate pathway. Because there has been controversy over the effects of statins on neuronal and cognitive function, we investigated the impact of long-term atorvastatin treatment (5mg/kg/d for 7 months by oral gavage) on behavior, cognition, and brain biochemistry in mice. We hypothesized that long-term statin treatment would alter lipid rafts and cognitive function. Atorvastatin treatment resulted in behavioral deficits as measured in paradigms for basic exploration (open field activity) and cognitive function (Barnes maze, startle response) without impairment in global motor function (Rotor Rod). Furthermore, significant changes in MLR-associated proteins (syntaxin-1α and synaptophysin) and a global change of post-synaptic density protein-95 (PSD95) were observed. The observed decreases in the MLR-localized pre-synaptic vesicle proteins syntaxin-1α and synaptophysin suggest a molecular mechanism for the statin-associated impairment of cognitive function that was observed and that has been suggested by the clinical literature. Published by Elsevier B.V.

  8. Nitrogen dioxide (NO(2)) pollution as a potential risk factor for developing vascular dementia and its synaptic mechanisms.

    Science.gov (United States)

    Li, Hongyan; Xin, Xiaoyun

    2013-06-01

    Recent epidemiological literatures reported that NO(2) is a potential risk factor of ischemic stroke in polluted area. Meanwhile, our previous in vivo study found that NO(2) could delay the recovery of nerve function after stroke, implying a possible risk of vascular dementia (VaD) with NO(2) inhalation, which is often a common cognitive complication resulting from stroke. However, the effect and detailed mechanisms have not been fully elucidated. In the present study, synaptic mechanisms, the foundation of neuronal function and viability, were investigated in both model rats of ischemic stroke and healthy rats after NO(2) exposure. Transmission electron microscope (TEM) observation showed that 5 mg m(-3) NO(2) exposure not only exacerbated the ultrastructural impairment of synapses in stroke model rats, but also induced neuronal damage in healthy rats. Meantime, we found that the expression of synaptophysin (SYP) and postsynaptic density protein 95 (PSD-95), two structural markers of synapses in ischemic stroke model were inhibited by NO(2) inhalation; and so it was with the key proteins mediating long-term potentiation (LTP), the major form of synaptic plasticity. On the contrary, NO(2) inhalation induced the expression of nearly all these proteins in healthy rats in a concentration-dependent manner. Our results implied that NO(2) exposure could increase the risk of VaD through inducing excitotoxicity in healthy rats but weakening synaptic plasticity directly in stroke model rats. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. LRRTM3 Regulates Excitatory Synapse Development through Alternative Splicing and Neurexin Binding

    Directory of Open Access Journals (Sweden)

    Ji Won Um

    2016-02-01

    Full Text Available The four members of the LRRTM family (LRRTM1-4 are postsynaptic adhesion molecules essential for excitatory synapse development. They have also been implicated in neuropsychiatric diseases. Here, we focus on LRRTM3, showing that two distinct LRRTM3 variants generated by alternative splicing regulate LRRTM3 interaction with PSD-95, but not its excitatory synapse-promoting activity. Overexpression of either LRRTM3 variant increased excitatory synapse density in dentate gyrus (DG granule neurons, whereas LRRTM3 knockdown decreased it. LRRTM3 also controlled activity-regulated AMPA receptor surface expression in an alternative splicing-dependent manner. Furthermore, Lrrtm3-knockout mice displayed specific alterations in excitatory synapse density, excitatory synaptic transmission and excitability in DG granule neurons but not in CA1 pyramidal neurons. Lastly, LRRTM3 required only specific splice variants of presynaptic neurexins for their synaptogenic activity. Collectively, our data highlight alternative splicing and differential presynaptic ligand utilization in the regulation of LRRTMs, revealing key regulatory mechanisms for excitatory synapse development.

  10. SPIN90 Modulates Long-Term Depression and Behavioral Flexibility in the Hippocampus

    Directory of Open Access Journals (Sweden)

    Dae Hwan Kim

    2017-09-01

    Full Text Available The importance of actin-binding proteins (ABPs in the regulation of synapse morphology and plasticity has been well established. SH3 protein interacting with Nck, 90 kDa (SPIN90, an Nck-interacting protein highly expressed in synapses, is essential for actin remodeling and dendritic spine morphology. Synaptic targeting of SPIN90 to spine heads or dendritic shafts depends on its phosphorylation state, leading to blockage of cofilin-mediated actin depolymerization and spine shrinkage. However, the physiological role of SPIN90 in long-term plasticity, learning and memory are largely unknown. In this study, we demonstrate that Spin90-knockout (KO mice exhibit substantial deficits in synaptic plasticity and behavioral flexibility. We found that loss of SPIN90 disrupted dendritic spine density in CA1 neurons of the hippocampus and significantly impaired long-term depression (LTD, leaving basal synaptic transmission and long-term potentiation (LTP intact. These impairments were due in part to deficits in AMPA receptor endocytosis and its pre-requisites, GluA1 dephosphorylation and postsynaptic density (PSD 95 phosphorylation, but also by an intrinsic activation of Akt-GSK3β signaling as a result of Spin90-KO. In accordance with these defects, mice lacking SPIN90 were found to carry significant deficits in object-recognition and behavioral flexibility, while learning ability was largely unaffected. Collectively, these findings demonstrate a novel modulatory role for SPIN90 in hippocampal LTD and behavioral flexibility.

  11. The Gαo Activator Mastoparan-7 Promotes Dendritic Spine Formation in Hippocampal Neurons

    Directory of Open Access Journals (Sweden)

    Valerie T. Ramírez

    2016-01-01

    Full Text Available Mastoparan-7 (Mas-7, an analogue of the peptide mastoparan, which is derived from wasp venom, is a direct activator of Pertussis toxin- (PTX- sensitive G proteins. Mas-7 produces several biological effects in different cell types; however, little is known about how Mas-7 influences mature hippocampal neurons. We examined the specific role of Mas-7 in the development of dendritic spines, the sites of excitatory synaptic contact that are crucial for synaptic plasticity. We report here that exposure of hippocampal neurons to a low dose of Mas-7 increases dendritic spine density and spine head width in a time-dependent manner. Additionally, Mas-7 enhances postsynaptic density protein-95 (PSD-95 clustering in neurites and activates Gαo signaling, increasing the intracellular Ca2+ concentration. To define the role of signaling intermediates, we measured the levels of phosphorylated protein kinase C (PKC, c-Jun N-terminal kinase (JNK, and calcium-calmodulin dependent protein kinase IIα (CaMKIIα after Mas-7 treatment and determined that CaMKII activation is necessary for the Mas-7-dependent increase in dendritic spine density. Our results demonstrate a critical role for Gαo subunit signaling in the regulation of synapse formation.

  12. Latrophilin 1 and its endogenous ligand Lasso/teneurin-2 form a high-affinity transsynaptic receptor pair with signaling capabilities.

    Science.gov (United States)

    Silva, John-Paul; Lelianova, Vera G; Ermolyuk, Yaroslav S; Vysokov, Nickolai; Hitchen, Paul G; Berninghausen, Otto; Rahman, M Atiqur; Zangrandi, Alice; Fidalgo, Sara; Tonevitsky, Alexander G; Dell, Anne; Volynski, Kirill E; Ushkaryov, Yuri A

    2011-07-19

    Latrophilin 1 (LPH1), a neuronal receptor of α-latrotoxin, is implicated in neurotransmitter release and control of presynaptic Ca(2+). As an "adhesion G-protein-coupled receptor," LPH1 can convert cell surface interactions into intracellular signaling. To examine the physiological functions of LPH1, we used LPH1's extracellular domain to purify its endogenous ligand. A single protein of ∼275 kDa was isolated from rat brain and termed Lasso. Peptide sequencing and molecular cloning have shown that Lasso is a splice variant of teneurin-2, a brain-specific orphan cell surface receptor with a function in neuronal pathfinding and synaptogenesis. We show that LPH1 and Lasso interact strongly and specifically. They are always copurified from rat brain extracts. Coculturing cells expressing LPH1 with cells expressing Lasso leads to their mutual attraction and formation of multiple junctions to which both proteins are recruited. Cells expressing LPH1 form chimerical synapses with hippocampal neurons in cocultures; LPH1 and postsynaptic neuronal protein PSD-95 accumulate on opposite sides of these structures. Immunoblotting and immunoelectron microscopy of purified synapses and immunostaining of cultured hippocampal neurons show that LPH1 and Lasso are enriched in synapses; in both systems, LPH1 is presynaptic, whereas Lasso is postsynaptic. A C-terminal fragment of Lasso interacts with LPH1 and induces Ca(2+) signals in presynaptic boutons of hippocampal neurons and in neuroblastoma cells expressing LPH1. Thus, LPH1 and Lasso can form transsynaptic complexes capable of inducing presynaptic Ca(2+) signals, which might affect synaptic functions.

  13. Latrophilin 1 and its endogenous ligand Lasso/teneurin-2 form a high-affinity transsynaptic receptor pair with signaling capabilities

    Science.gov (United States)

    Silva, John-Paul; Lelianova, Vera G.; Ermolyuk, Yaroslav S.; Vysokov, Nickolai; Hitchen, Paul G.; Berninghausen, Otto; Rahman, M. Atiqur; Zangrandi, Alice; Fidalgo, Sara; Tonevitsky, Alexander G.; Dell, Anne; Volynski, Kirill E.; Ushkaryov, Yuri A.

    2011-01-01

    Latrophilin 1 (LPH1), a neuronal receptor of α-latrotoxin, is implicated in neurotransmitter release and control of presynaptic Ca2+. As an “adhesion G-protein-coupled receptor,” LPH1 can convert cell surface interactions into intracellular signaling. To examine the physiological functions of LPH1, we used LPH1’s extracellular domain to purify its endogenous ligand. A single protein of ∼275 kDa was isolated from rat brain and termed Lasso. Peptide sequencing and molecular cloning have shown that Lasso is a splice variant of teneurin-2, a brain-specific orphan cell surface receptor with a function in neuronal pathfinding and synaptogenesis. We show that LPH1 and Lasso interact strongly and specifically. They are always copurified from rat brain extracts. Coculturing cells expressing LPH1 with cells expressing Lasso leads to their mutual attraction and formation of multiple junctions to which both proteins are recruited. Cells expressing LPH1 form chimerical synapses with hippocampal neurons in cocultures; LPH1 and postsynaptic neuronal protein PSD-95 accumulate on opposite sides of these structures. Immunoblotting and immunoelectron microscopy of purified synapses and immunostaining of cultured hippocampal neurons show that LPH1 and Lasso are enriched in synapses; in both systems, LPH1 is presynaptic, whereas Lasso is postsynaptic. A C-terminal fragment of Lasso interacts with LPH1 and induces Ca2+ signals in presynaptic boutons of hippocampal neurons and in neuroblastoma cells expressing LPH1. Thus, LPH1 and Lasso can form transsynaptic complexes capable of inducing presynaptic Ca2+ signals, which might affect synaptic functions. PMID:21724987

  14. Neuroligin-1 loss is associated with reduced tenacity of excitatory synapses.

    Directory of Open Access Journals (Sweden)

    Adel Zeidan

    Full Text Available Neuroligins (Nlgns are postsynaptic, integral membrane cell adhesion molecules that play important roles in the formation, validation, and maturation of synapses in the mammalian central nervous system. Given their prominent roles in the life cycle of synapses, it might be expected that the loss of neuroligin family members would affect the stability of synaptic organization, and ultimately, affect the tenacity and persistence of individual synaptic junctions. Here we examined whether and to what extent the loss of Nlgn-1 affects the dynamics of several key synaptic molecules and the constancy of their contents at individual synapses over time. Fluorescently tagged versions of the postsynaptic scaffold molecule PSD-95, the AMPA-type glutamate receptor subunit GluA2 and the presynaptic vesicle molecule SV2A were expressed in primary cortical cultures from Nlgn-1 KO mice and wild-type (WT littermates, and live imaging was used to follow the constancy of their contents at individual synapses over periods of 8-12 hours. We found that the loss of Nlgn-1 was associated with larger fluctuations in the synaptic contents of these molecules and a poorer preservation of their contents at individual synapses. Furthermore, rates of synaptic turnover were somewhat greater in neurons from Nlgn-1 knockout mice. Finally, the increased GluA2 redistribution rates observed in neurons from Nlgn-1 knockout mice were negated by suppressing spontaneous network activity. These findings suggest that the loss of Nlgn-1 is associated with some use-dependent destabilization of excitatory synapse organization, and indicate that in the absence of Nlgn-1, the tenacity of excitatory synapses might be somewhat impaired.

  15. Analysis of pre- and postsynaptic factors of the serotonin system in rabbit retina

    OpenAIRE

    1985-01-01

    [3H]Serotonin is accumulated by a specific set of amacrine cells in the rabbit retina. These cells also accumulate the neurotoxin, 5,7- dihydroxytryptamine, and show signs of necrosis within 4 h of in vivo exposure to the drug. Biochemical analysis of [3H]serotonin uptake reveal a sodium- and temperature-dependent, high affinity uptake system with a Km of 0.94 microM and Vmax of 1.08 pmol/mg protein/min. [3H]Tryptophan is also accumulated in rabbit retinal homogenates by a high affinity proce...

  16. High frequency switched-mode stimulation can evoke postsynaptic responses in cerebellar principal neurons

    Directory of Open Access Journals (Sweden)

    Marijn Van Dongen

    2015-03-01

    Full Text Available This paper investigates the efficacy of high frequency switched-mode neural stimulation. Instead of using a constant stimulation amplitude, the stimulus is switched on and off repeatedly with a high frequency (up to 100kHz duty cycled signal. By means of tissue modeling that includes the dynamic properties of both the tissue material as well as the axon membrane, it is first shown that switched-mode stimulation depolarizes the cell membrane in a similar way as classical constant amplitude stimulation.These findings are subsequently verified using in vitro experiments in which the response of a Purkinje cell is measured due to a stimulation signal in the molecular layer of the cerebellum of a mouse. For this purpose a stimulator circuit is developed that is able to produce a monophasic high frequency switched-mode stimulation signal. The results confirm the modeling by showing that switched-mode stimulation is able to induce similar responses in the Purkinje cell as classical stimulation using a constant current source. This conclusion opens up possibilities for novel stimulation designs that can improve the performance of the stimulator circuitry. Care has to be taken to avoid losses in the system due to the higher operating frequency.

  17. In vivo calcium accumulation in presynaptic and postsynaptic dendrites of visual interneurons

    OpenAIRE

    Dürr, Volker; Egelhaaf, Martin

    1999-01-01

    In this comparative in vivo study of dendritic calcium accumulation, we describe the time course and spatial integration properties of two classes of visual interneurons in the lobula plate of the blowfly. Calcium accumulation was measured during visual motion stimulation, ensuring synaptic activation of the neurons within their natural spatial and temporal operating range. The compared cell classes, centrifugal horizontal (CH) and horizontal system (HS) cells, are known to receive retinotopi...

  18. PRE- AND POSTSYNAPTIC NEUROMUSCULAR JUNCTION ABNORMALITIES IN MuSK MYASTHENIA

    NARCIS (Netherlands)

    Niks, Erik H.; Kuks, Jan B. M.; Wokke, John H. J.; Veldman, Henk; Bakker, Egbert; Verschuuren, Jan J. G. M.; Plomp, Jaap J.

    Autoantibodies to muscle-specific kinase (MuSK) can cause myasthenia gravis (MG). The pathophysiological mechanism remains unknown. We report in vitro electrophysiological and histological studies of the neuromuscular junction in a MuSK MG patient. Low levels of presynaptic acetylcholine release and

  19. Simulating the Effects of Short-Term Synaptic Plasticity on Postsynaptic Dynamics in the Globus Pallidus

    Directory of Open Access Journals (Sweden)

    Moran eBrody

    2013-08-01

    Full Text Available The rat globus pallidus (GP is one of the nuclei of the basal ganglia and plays an important role in a variety of motor and cognitive processes. In vivo studies have shown that repetitive stimulation evokes complex modulations of GP activity. In vitro and computational studies have suggested that short-term synaptic plasticity (STP could be one of the underlying mechanisms. The current study used simplified single compartment modeling to explore the possible effect of STP on the activity of GP neurons during low and high frequency stimulation. To do this we constructed a model of a GP neuron connected to a small network of neurons from the three major input sources to GP neurons: striatum (Str, subthalamic nucleus (STN and GP collaterals. All synapses were implemented with a kinetic model of STP. The in vitro recordings of responses to low frequency repetitive stimulation were highly reconstructed, including rate changes and locking to the stimulus. Mainly involved were fast forms of plasticity which have been found at these synapses. . The simulations were qualitatively compared to a data set previously recorded in vitro in our lab. Reconstructions of experimental responses to high frequency stimulation required adding slower forms of plasticity to the STN and GP collateral synapses, as well as adding metabotropic receptors to the STN-GP synapses. These finding suggest the existence of as yet unreported slower short-term dynamics in the GP. The computational model made additional predictions about GP activity during low and high frequency stimulation that may further our understanding of the mechanisms underlying repetative stimulation of the GP.

  20. Decreased postsynaptic dopaminergic and cholinergic functions in the ventrolateral striatum of spontaneously hypertensive rat.

    NARCIS (Netherlands)

    Fujita, S.; Adachi, K.; Lee, J.; Uchida, T.; Koshikawa, N.; Cools, A.R.

    2004-01-01

    Dopamine and acetylcholine receptor functions in spontaneously hypertensive rats (SHR) and in control progenitor Wistar-Kyoto (WKY) rats were assessed, using dopamine D1-like/D2-like receptor-mediated and acetylcholine receptor-mediated jaw movements as readout parameters. Spontaneous behaviours

  1. Pre- and postsynaptic inhibitory potencies of the angiotensin AT(1) receptor antagonists eprosartan and candesartan

    NARCIS (Netherlands)

    Nap, Alexander; Mathy, Marie-Jeanne; Balt, Jippe C.; Pfaffendorf, Martin; van Zwieten, Pieter A.

    2003-01-01

    The aim of the present study was to determine the inhibitory potency of two selective angiotensin AT, receptor antagonists, eprosartan and candesartan, at the level of the sympathetic nerve terminal and the vascular smooth muscle. Male New Zealand White rabbits, weighing 2100-2550 g, were used. To

  2. Development of Glutamatergic Proteins in Human Visual Cortex across the Lifespan.

    Science.gov (United States)

    Siu, Caitlin R; Beshara, Simon P; Jones, David G; Murphy, Kathryn M

    2017-06-21

    Traditionally, human primary visual cortex (V1) has been thought to mature within the first few years of life, based on anatomical studies of synapse formation, and establishment of intracortical and intercortical connections. Human vision, however, develops well beyond the first few years. Previously, we found prolonged development of some GABAergic proteins in human V1 (Pinto et al., 2010). Yet as >80% of synapses in V1 are excitatory, it remains unanswered whether the majority of synapses regulating experience-dependent plasticity and receptive field properties develop late, like their inhibitory counterparts. To address this question, we used Western blotting of postmortem tissue from human V1 (12 female, 18 male) covering a range of ages. Then we quantified a set of postsynaptic glutamatergic proteins (PSD-95, GluA2, GluN1, GluN2A, GluN2B), calculated indices for functional pairs that are developmentally regulated (GluA2:GluN1; GluN2A:GluN2B), and determined interindividual variability. We found early loss of GluN1, prolonged development of PSD-95 and GluA2 into late childhood, protracted development of GluN2A until ∼40 years, and dramatic loss of GluN2A in aging. The GluA2:GluN1 index switched at ∼1 year, but the GluN2A:GluN2B index continued to shift until ∼40 year before changing back to GluN2B in aging. We also identified young childhood as a stage of heightened interindividual variability. The changes show that human V1 develops gradually through a series of five orchestrated stages, making it likely that V1 participates in visual development and plasticity across the lifespan. SIGNIFICANCE STATEMENT Anatomical structure of human V1 appears to mature early, but vision changes across the lifespan. This discrepancy has fostered two hypotheses: either other aspects of V1 continue changing, or later changes in visual perception depend on extrastriate areas. Previously, we showed that some GABAergic synaptic proteins change across the lifespan, but most

  3. Human Neural Cell-Based Biosensor

    Science.gov (United States)

    2010-04-26

    95 eGFP pCMV PSD-95 mCherry pECFP PSD-95 CFP Discs, large homolog 4 (PSD-95) Post synaptic density protein ; post- synaptic marker pKv4.2-eGFP...NLGN4) Brain-specific, post synaptic membrane protein pNICENeurexin1 beta – CFP Neurexin-1-beta (NRXN1) role in synaptogenesis; interacts with...localization of lectin binding. Lectins are carbohydrate binding proteins that recognize diverse sugar structures. Here we used a panel of 8 lectins to

  4. Dopaminergic dysregulation in prefrontal cortex of rhesus monkeys following cocaine self-administration

    Directory of Open Access Journals (Sweden)

    Scot eMcIntosh

    2013-08-01

    Full Text Available Chronic cocaine administration regulates the expression of several proteins related to dopaminergic signaling and synaptic function in the mesocorticolimbic pathway, including the prefrontal cortex. Functional abnormalities in the prefrontal cortex are hypothesized to be due in part to the expression of proteins involved in dopamine signaling and plasticity. Adult male rhesus monkeys self-administered cocaine (i.v. under limited (n=4 and extended access conditions (n=6. The abundance of surrogate markers of dopamine signaling and plasticity in the dorsolateral prefrontal cortex (DLPFC, orbitofrontal cortex (OFC and anterior cingulate cortex (ACC were examined: glycosylated and non-glycosylated forms of the dopamine transporter (efficiency of dopamine transport, tyrosine hydroxylase (TH; marker of dopamine synthesis and phosphorylated TH at Serine 30 and 40 (markers of enzyme activity, extracellular signal-regulated kinase 1 and 2 (ERK1 and ERK 2 and phosphorylated ERK1 and ERK2 (phosphorylates TH Serine 31; markers of synaptic plasticity, and markers of synaptic integrity, spinophilin and post-synaptic density protein 95 (roles in dopamine signaling and response to cocaine. Extended cocaine access increased non-glycosylated and glycosylated DAT in DLPFC and OFC. While no differences in TH expression were observed between groups for any of the regions, extended access induced significant elevations in pTHSer31 in all regions. In addition, a slight but significant reduction in phosphorylated pTHSer40 was found in the DLPFC. Phosphorylated ERK2 was increased in all regions; however, pERK1 was decreased in ACC and OFC but increased in DLPFC. PSD-95 was increased in the OFC but not in DLPFC or ACC. Furthermore, extended cocaine self-administration elicited significant increases in spinophilin protein expression in all regions. Results from the study provide insight into the biochemical alterations occurring in primate prefrontal cortex.

  5. Indirubin Derivative 7-Bromoindirubin-3-Oxime (7Bio Attenuates Aβ Oligomer-Induced Cognitive Impairments in Mice

    Directory of Open Access Journals (Sweden)

    Liping Chen

    2017-11-01

    Full Text Available Indirubins are natural occurring alkaloids extracted from indigo dye-containing plants. Indirubins could inhibit various kinases, and might be used to treat chronic myelocytic leukemia, cancer and neurodegenerative disorders. 7-bromoindirubin-3-oxime (7Bio, an indirubin derivative derived from indirubin-3-oxime, possesses inhibitory effects against cyclin-dependent kinase-5 (CDK5 and glycogen synthase kinase-3β (GSK3β, two pharmacological targets of Alzheimer's disease (AD. In this study, we have discovered that 2.3–23.3 μg/kg 7Bio effectively prevented β-amyloid (Aβ oligomer-induced impairments of spatial cognition and recognition without affecting bodyweight and motor functions in mice. Moreover, 7Bio potently inhibited Aβ oligomer-induced expression of interleukin-6 (IL-6 and tumor necrosis factor-α (TNF-α. Furthermore, 7Bio significantly prevented the decreased expression of synapsin-1 and PSD-95, biomarkers of pre-synaptic and post-synaptic proteins in Aβ oligomer-treated mice. The mean optical density (OD with hyper-phosphorylated tau (pTau, glial fibrillary acidic protein (GFAP and CD45 positive staining in the hippocampus of 7Bio-treated mice were significantly decreased compared to those of Aβ oligomer-treated mice. In addition, Western blotting analysis showed that 7Bio attenuated Aβ oligomer-decreased expression of pSer9-GSK3β. Those results suggested that 7Bio could potently inhibit Aβ oligomer-induced neuroinflammation, synaptic impairments, tau hyper-phosphorylation, and activation of astrocytes and microglia, which may contribute to the neuroprotective effects of 7Bio. Based on these findings, we expected that 7Bio might be developed as a novel anti-AD lead compound.

  6. Ginger improves cognitive function via NGF-induced ERK/CREB activation in the hippocampus of the mouse.

    Science.gov (United States)

    Lim, Soonmin; Moon, Minho; Oh, Hyein; Kim, Hyo Geun; Kim, Sun Yeou; Oh, Myung Sook

    2014-10-01

    Ginger (the rhizome of Zingiber officinale Roscoe) has been used worldwide for many centuries in cooking and for treatment of several diseases. The main pharmacological properties of ginger include anti-inflammatory, antihyperglycemic, antiarthritic, antiemetic and neuroprotective actions. Recent studies demonstrated that ginger significantly enhances cognitive function in various cognitive disorders as well as in healthy brain. However, the biochemical mechanisms underlying the ginger-mediated enhancement of cognition have not yet been studied in normal or diseased brain. In the present study, we assessed the memory-enhancing effects of dried ginger extract (GE) in a model of scopolamine-induced memory deficits and in normal animals by performing a novel object recognition test. We found that GE administration significantly improved the ability of mice to recognize novel objects, indicating improvements in learning and memory. Furthermore, to elucidate the mechanisms of GE-mediated cognitive enhancement, we focused on nerve growth factor (NGF)-induced signaling pathways. NGF enzyme-linked immunosorbent assay analysis revealed that GE administration led to elevated NGF levels in both the mouse hippocampus and rat glioma C6 cells. GE administration also resulted in phosphorylation of extracellular-signal-regulated kinase (ERK) and cyclic AMP response element-binding protein (CREB), as revealed by Western blotting analysis. Neutralization of NGF with a specific NGF antibody inhibited GE-triggered activation of ERK and CREB in the hippocampus. Also, GE treatment significantly increased pre- and postsynaptic markers, synaptophysin and PSD-95, which are related to synapse formation in the brain. These data suggest that GE has a synaptogenic effect via NGF-induced ERK/CREB activation, resulting in memory enhancement. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Long-term green tea catechin administration prevents spatial learning and memory impairment in senescence-accelerated mouse prone-8 mice by decreasing Abeta1-42 oligomers and upregulating synaptic plasticity-related proteins in the hippocampus.

    Science.gov (United States)

    Li, Q; Zhao, H F; Zhang, Z F; Liu, Z G; Pei, X R; Wang, J B; Li, Y

    2009-10-20

    The senescence-accelerated mouse prone-8 (SAMP8) is characterized by early onset of learning and memory deficits along with spontaneous overproduction of soluble beta-amyloid peptide (Abeta) in the brain. In our study, 4 month old male SAMP8 mice were orally administered 0.05% and 0.1% green tea catechins (GTC, w/v) in drinking water for 6 months. We found that a supplementation with 0.05% or 0.1% GTC prevented spatial learning and memory impairments of mice in the Morris water maze. Better performance of GTC-treated mice was associated with decreased levels of Abeta(1-42) oligomers in the hippocampus. The activity of the protein kinase A/cAMP-response element binding protein (PKA/CREB) pathway, one of the molecular targets of Abeta oligomers which is crucial for late long-term potentiation and long-term memory formation, was significantly increased after GTC administration. We also found that chronic 0.05% or 0.1% GTC consumption prevented the reductions of three representative proteins of synaptic function and synaptic structure, including brain-derived neurotrophic factor(BDNF), post-synaptic density protein-95 (PSD95) and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). These results demonstrated that long-term 0.05% or 0.1% green tea catechin administration may prevent spatial learning and memory decline of SAMP8 mice by decreasing Abeta(1-42) oligomers and upregulating synaptic plasticity-related proteins in the hippocampus.

  8. Kalirin Binds the NR2B Subunit of the NMDA Receptor, Altering Its Synaptic Localization and Function

    KAUST Repository

    Kiraly, D. D.

    2011-08-31

    The ability of dendritic spines to change size and shape rapidly is critical in modulating synaptic strength; these morphological changes are dependent upon rearrangements of the actin cytoskeleton. Kalirin-7 (Kal7), a Rho guanine nucleotide exchange factor localized to the postsynaptic density (PSD), modulates dendritic spine morphology in vitro and in vivo. Kal7 activates Rac and interacts with several PSD proteins, including PSD-95, DISC-1, AF-6, and Arf6. Mice genetically lacking Kal7 (Kal7KO) exhibit deficient hippocampal long-term potentiation (LTP) as well as behavioral abnormalities in models of addiction and learning. Purified PSDs from Kal7KO mice contain diminished levels of NR2B, an NMDA receptor subunit that plays a critical role in LTP induction. Here we demonstrate that Kal7KO animals have decreased levels of NR2B-dependent NMDA receptor currents in cortical pyramidal neurons as well as a specific deficit in cell surface expression of NR2B. Additionally, we demonstrate that the genotypic differences in conditioned place preference and passive avoidance learning seen in Kal7KO mice are abrogated when animals are treated with an NR2B-specific antagonist during conditioning. Finally, we identify a stable interaction between the pleckstrin homology domain of Kal7 and the juxtamembrane region of NR2B preceding its cytosolic C-terminal domain. Binding of NR2B to a protein that modulates the actin cytoskeleton is important, as NMDA receptors require actin integrity for synaptic localization and function. These studies demonstrate a novel and functionally important interaction between the NR2B subunit of the NMDA receptor and Kalirin, proteins known to be essential for normal synaptic plasticity.

  9. Induction of the GABA cell phenotype: an in vitro model for studying neurodevelopmental disorders.

    Directory of Open Access Journals (Sweden)

    Sivan Subburaju

    Full Text Available Recent studies of the hippocampus have suggested that a network of genes is associated with the regulation of the GAD₆₇ (GAD1 expression and may play a role in γ-amino butyric acid (GABA dysfunction in schizophrenia (SZ and bipolar disorder (BD. To obtain a more detailed understanding of how GAD₆₇ regulation may result in GABAergic dysfunction, we have developed an in vitro model in which GABA cells are differentiated from the hippocampal precursor cell line, HiB5. Growth factors, such as PDGF, and BDNF, regulate the GABA phenotype by inducing the expression of GAD₆₇ and stimulating the growth of cellular processes, many with growth cones that form appositions with the cell bodies and processes of other GAD₆₇-positive cells. These changes are associated with increased expression of acetylated tubulin, microtubule-associated protein 2 (MAP2 and the post-synaptic density protein 95 (PSD95. The addition of BDNF, together with PDGF, increases the levels of mRNA and protein for GAD₆₇, as well as the high affinity GABA uptake protein, GAT1. These changes are associated with increased concentrations of GABA in the cytoplasm of "differentiated" HiB5 neurons. In the presence of Ca²⁺ and K⁺, newly synthesized GABA is released extracellularly. When the HiB5 cells appear to be fully differentiated, they also express GAD₆₅, parvalbumin and calbindin, and GluR subtypes as well as HDAC1, DAXX, PAX5, Runx2, associated with GAD₆₇ regulation. Overall, these results suggest that the HiB5 cells can differentiate into functionally mature GABA neurons in the presence of gene products that are associated with GAD₆₇ regulation in the adult hippocampus.

  10. Neuroprotection by donepezil against glutamate excitotoxicity involves stimulation of α7 nicotinic receptors and internalization of NMDA receptors

    Science.gov (United States)

    Shen, H; Kihara, T; Hongo, H; Wu, X; Kem, WR; Shimohama, S; Akaike, A; Niidome, T; Sugimoto, H

    2010-01-01

    BACKGROUND AND PURPOSE Glutamate excitotoxicity may be involved in ischaemic injury to the CNS and some neurodegenerative diseases, such as Alzheimer's disease. Donepezil, an acetylcholinesterase (AChE) inhibitor, exerts neuroprotective effects. Here we demonstrated a novel mechanism underlying the neuroprotection induced by donepezil. EXPERIMENTAL APPROACH Cell damage in primary rat neuron cultures was quantified by lactate dehydrogenase release. Morphological changes associated with neuroprotective effects of nicotine and AChE inhibitors were assessed by immunostaining. Cell surface levels of the glutamate receptor sub-units, NR1 and NR2A, were analyzed using biotinylation. Immunoblot was used to measure protein levels of cleaved caspase-3, total NR1, total NR2A and phosphorylated NR1. Immunoprecipitation was used to measure association of NR1 with the post-synaptic protein, PSD-95. Intracellular Ca2+ concentrations were measured with fura 2-acetoxymethylester. Caspase 3-like activity was measured using enzyme substrate, 7-amino-4-methylcoumarin (AMC)-DEVD. KEY RESULTS Levels of NR1, a core subunit of the NMDA receptor, on the cell surface were significantly reduced by donepexzil. In addition, glutamate-mediated Ca2+ entry was significantly attenuated by donepezil. Methyllycaconitine, an inhibitor of α7 nicotinic acetylcholine receptors (nAChR), inhibited the donepezil-induced attenuation of glutamate-mediated Ca2+ entry. LY294002, a phosphatidyl inositol 3-kinase (PI3K) inhibitor, had no effect on attenuation of glutamate-mediated Ca2+ entry induced by donepezil. CONCLUSIONS AND IMPLICATIONS Decreased glutamate toxicity through down-regulation of NMDA receptors, following stimulation of α7 nAChRs, could be another mechanism underlying neuroprotection by donepezil, in addition to up-regulating the PI3K-Akt cascade or defensive system. PMID:20718745

  11. Neonatal Exposure to Low-Dose (1.2%) Sevoflurane Increases Rats' Hippocampal Neurogenesis and Synaptic Plasticity in Later Life.

    Science.gov (United States)

    Chen, Xi; Zhou, Xue; Yang, Lu; Miao, Xu; Lu, Di-Han; Yang, Xiao-Yu; Zhou, Zhi-Bin; Kang, Wen-Bin; Chen, Ke-Yu; Zhou, Li-Hua; Feng, Xia

    2018-02-09

    The increasing usage of general anesthetics on young children and infants has drawn extensive attention to the effects of these drugs on cognitive function later in life. Recent animal studies have revealed improvement in hippocampus-dependent performance after lower concentrations of sevoflurane exposure. However, the long-term effects of low-dose sevoflurane on the developing brain remain elusive. On postnatal day (P) 7, rats were treated with 1.2% sevoflurane (1.2% sevo group), 2.4% sevoflurane (2.4% sevo group), and air control (C group) for 6 h. On P35-40, rats' hippocampus-dependent learning and memory was tested using the Morris water maze. Cognition-related and synapse-related proteins in the hippocampus were measured using Western blotting on P35. On the same day, neurogenesis and synapse ultrastructure were evaluated using immunofluorescence and transmission electron microscopy (TEM). On P35, the rats neonatally exposed to 1.2% sevoflurane showed better behavioral results than control rats, but not in the 2.4% sevo group. Exposure to 1.2% sevoflurane increased the number of 5'-bromo-2-deoxyuridine (BrdU)-positive cells in the dentate gyrus and improved both synaptic number and ultrastructure in the hippocampus. The expression levels of BDNF, TrkB, postsynaptic density (PSD)-95, and synaptophysin in the hippocampus were also increased in the 1.2% sevo group. In contrast, no significant changes in neurogenesis or synaptic plasticity were observed between the C group and the 2.4% sevo group on P35. These results showed that exposure of the developing brain to a low concentration of sevoflurane for 6 h could promote spatial learning and memory function, along with increased hippocampal neurogenesis and synaptic plasticity, in later life.

  12. Voluntary Exercise Promotes Glymphatic Clearance of Amyloid Beta and Reduces the Activation of Astrocytes and Microglia in Aged Mice

    Directory of Open Access Journals (Sweden)

    Xiao-fei He

    2017-05-01

    Full Text Available Age is characterized by chronic inflammation, leading to synaptic dysfunction and dementia because the clearance of protein waste is reduced. The clearance of proteins depends partly on the permeation of the blood–brain barrier (BBB or on the exchange of water and soluble contents between the cerebrospinal fluid (CSF and the interstitial fluid (ISF. A wealth of evidence indicates that physical exercise improves memory and cognition in neurodegenerative diseases during aging, such as Alzheimer’s disease (AD, but the influence of physical training on glymphatic clearance, BBB permeability and neuroinflammation remains unclear. In this study, glymphatic clearance and BBB permeability were evaluated in aged mice using in vivo two-photon imaging. The mice performed voluntary wheel running exercise and their water-maze cognition was assessed; the expression of the astrocytic water channel aquaporin 4 (AQP4, astrocyte and microglial activation, and the accumulation of amyloid beta (Aβ were evaluated with immunofluorescence or an enzyme-linked immunosorbent assay (ELISA; synaptic function was investigated with Thy1–green fluorescent protein (GFP transgenic mice and immunofluorescent staining. Voluntary wheel running significantly improved water-maze cognition in the aged mice, accelerated the efficiency of glymphatic clearance, but which did not affect BBB permeability. The numbers of activated astrocytes and microglia decreased, AQP4 expression increased, and the distribution of astrocytic AQP4 was rearranged. Aβ accumulation decreased, whereas dendrites, dendritic spines and postsynaptic density protein (PSD95 increased. Our study suggests that voluntary wheel running accelerated glymphatic clearance but not BBB permeation, improved astrocytic AQP4 expression and polarization, attenuated the accumulation of amyloid plaques and neuroinflammation, and ultimately protected mice against synaptic dysfunction and a decline in spatial cognition

  13. Melatonin attenuates impairments of structural hippocampal neuroplasticity in OXYS rats during active progression of Alzheimer's disease-like pathology.

    Science.gov (United States)

    Stefanova, Natalia A; Maksimova, Kseniya Y; Kiseleva, Elena; Rudnitskaya, Ekaterina A; Muraleva, Natalia A; Kolosova, Nataliya G

    2015-09-01

    Translational research on Alzheimer's disease (AD) has often focused on reducing the high cerebral levels of amyloid-β (Aβ) as a key characteristic of AD pathogenesis. There is, however, a growing body of evidence that synaptic dysfunction may be crucial for the development of the most common (sporadic) form of AD. The applicability of melatonin (mainly produced by the pineal gland) to the treatment of AD is actively evaluated, but usually, such studies are based on animal models of early-onset AD, which is responsible for only ~5% of AD cases. We have shown previously that in OXYS rats (an established model of sporadic AD), accumulation of toxic forms of Aβ in the brain occurs later than does the development of signs of neurodegenerative changes and synaptic failure. In this regard, recently, we uncovered beneficial neuroprotective effects of melatonin (prophylactic dietary supplementation) in OXYS rats. Our aim here was to evaluate, starting at the age of active progression of AD-like pathology in OXYS rats, the effects of long-term oral administration of melatonin on the structure of synapses and on neuronal and glial cells of the hippocampus. Melatonin significantly increased hippocampal synaptic density and the number of excitatory synapses, decreased the number of inhibitory synapses, and upregulated pre- and postsynaptic proteins (synapsin I and PSD-95, respectively). Furthermore, melatonin improved the ultrastructure of neuronal and glial cells and reduced glial density. Based on our past and present results, the repair of neuroplasticity by melatonin is a promising strategy against AD. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. NMDA receptors mediate synaptic competition in culture.

    Directory of Open Access Journals (Sweden)

    Kevin She

    Full Text Available Activity through NMDA type glutamate receptors sculpts connectivity in the developing nervous system. This topic is typically studied in the visual system in vivo, where activity of inputs can be differentially regulated, but in which individual synapses are difficult to visualize and mechanisms governing synaptic competition can be difficult to ascertain. Here, we develop a model of NMDA-receptor dependent synaptic competition in dissociated cultured hippocampal neurons.GluN1 -/- (KO mouse hippocampal neurons lacking the essential NMDA receptor subunit were cultured alone or cultured in defined ratios with wild type (WT neurons. The absence of functional NMDA receptors did not alter neuron survival. Synapse development was assessed by immunofluorescence for postsynaptic PSD-95 family scaffold and apposed presynaptic vesicular glutamate transporter VGlut1. Synapse density was specifically enhanced onto minority wild type neurons co-cultured with a majority of GluN1 -/- neighbour neurons, both relative to the GluN1 -/- neighbours and relative to sister pure wild type cultures. This form of synaptic competition was dependent on NMDA receptor activity and not conferred by the mere physical presence of GluN1. In contrast to these results in 10% WT and 90% KO co-cultures, synapse density did not differ by genotype in 50% WT and 50% KO co-cultures or in 90% WT and 10% KO co-cultures.The enhanced synaptic density onto NMDA receptor-competent neurons in minority coculture with GluN1 -/- neurons represents a cell culture paradigm for studying synaptic competition. Mechanisms involved may include a retrograde 'reward' signal generated by WT neurons, although in this paradigm there was no 'punishment' signal against GluN1 -/- neurons. Cell culture assays involving such defined circuits may help uncover the rules and mechanisms of activity-dependent synaptic competition in the developing nervous system.

  15. Cotinine halts the advance of Alzheimer’s disease-like pathology and associated depressive-like behavior in Tg6799 mice

    Directory of Open Access Journals (Sweden)

    Sagar ePatel

    2014-07-01

    Full Text Available Alzheimer’s disease (AD is associated with cognitive and non-cognitive symptoms for which there are currently no effective therapies. We have previously reported that cotinine, a natural product obtained from tobacco leaves, prevented memory loss and diminished amyloid-β (Aβ plaque pathology in the transgenic 6799 mice (Tg6799 mice when treated prior to the development of the pathology. We have also shown that cotinine reduces depressive-like behavior in normal and chronically stressed C57BL/6 mice. Here, we extend our previous studies by investigating the effects of cotinine on the progression of AD-like pathology, depressive-like behavior, and the mechanisms underlying its beneficial effects in the Tg6799 mice when left untreated until after a more advanced stage of the disease’s development. The results show that vehicle-treated Tg6799 mice displayed an accentuated loss of working memory and an abundant Aβ plaque pathology that were accompanied by higher levels of depressive-like behavior as compared to control littermates. By contrast, prolonged daily cotinine treatment, withheld until after a mid-level progression of AD-like pathology, reduced Aβ levels, Aβ plaques, and depressive-like behavior as well as dramatically improved working memory in Tg6799 mice to levels no different from control littermates. The beneficial effects of cotinine were accompanied by an increase in the expression of the active form of protein kinase B (Akt and the postsynaptic density protein 95 (PSD95 in the hippocampi and frontal cortices of Tg6799 mice. This suggests that cotinine halts the progression of AD-like pathology while reducing depressive-like behavior by stimulating signaling pathways supporting synaptic plasticity in Tg6799 mice. The potential use of cotinine to treat cognitive and non-cognitive symptoms of AD is discussed.

  16. Homer2 deletion alters dendritic spine morphology but not alcohol-associated adaptations in GluN2B-containing NMDA receptors in the nucleus accumbens

    Directory of Open Access Journals (Sweden)

    Natalie S McGuier

    2015-02-01

    Full Text Available Repeated exposure to ethanol followed by withdrawal leads to the alterations in glutamatergic signaling and impaired synaptic plasticity in the nucleus accumbens (NAc in both clinical and preclinical models of ethanol exposure. Homer2 is a member of a family of postsynaptic density (PSD scaffolding proteins that functions in part to cluster NMDA signaling complexes in the PSD, and has been shown to be critically important for plasticity in multiple models of drug and alcohol abuse. Here we used Homer2 KO mice and a chronic intermittent intraperitoneal (IP ethanol injection model to investigate a potential role for the protein in ethanol-induced adaptations in dendritic spine morphology and PSD protein expression. While deletion of Homer2 was associated with increased density of long spines on medium spiny neurons of the NAc core of saline treated mice, ethanol exposure had no effect on dendritic spine morphology in either wild-type (WT or Homer2 KO mice. Western blot analysis of tissue samples from the NAc enriched for PSD proteins revealed a main effect of ethanol treatment on the expression of GluN2B, but there was no effect of genotype or treatment on the expression other glutamate receptor subunits or PSD95. These data indicate that the global deletion of Homer2 leads to aberrant regulation of dendritic spine morphology in the NAc core that is associated with an increased density of long, thin spines. Unexpectedly, intermittent IP ethanol did not affect spine morphology in either WT or KO mice. Together these data implicate Homer2 in the formation of long, thin spines and further supports its role in neuronal structure.

  17. Impaired ILK Function Is Associated with Deficits in Hippocampal Based Memory and Synaptic Plasticity in a FASD Rat Model.

    Directory of Open Access Journals (Sweden)

    D Bhattacharya

    Full Text Available Fetal Alcohol Spectrum Disorder (FASD is an umbrella term that encompasses a wide range of anatomical and behavioral problems in children who are exposed to alcohol during the prenatal period. There is no effective treatment for FASD, because of lack of complete characterization of the cellular and molecular mechanisms underlying this condition. Alcohol has been previously characterized to affect integrins and growth factor signaling receptors. Integrin Linked Kinase (ILK is an effector of integrin and growth-factor signaling which regulates various signaling processes. In FASD, a downstream effector of ILK, Glycogen Synthase Kinase 3β (GSK3β remains highly active (reduced Ser9 phosphorylation. GSK3β has been known to modulate glutamate receptor trafficking and channel properties. Therefore, we hypothesize that the cognitive deficits accompanying FASD are associated with impairments in the ILK signaling pathway. Pregnant Sprague Dawley rats consumed a "moderate" amount of alcohol throughout gestation, or a calorie-equivalent sucrose solution. Contextual fear conditioning was used to evaluate memory performance in 32-33-day-old pups. Synaptic plasticity was assessed in the Schaffer Collateral pathway, and hippocampal protein lysates were used to evaluate ILK signaling. Alcohol exposed pups showed impaired contextual fear conditioning, as compared to control pups. This reduced memory performance was consistent with decrease in LTP as compared to controls. Hippocampal ILK activity and GSK3β Ser21/9 phosphorylation were significantly lower in alcohol-exposed pups than controls. Increased synaptic expression of GluR2 AMPA receptors was observed with immunoprecipitation of post-synaptic density protein 95 (PSD95. Furthermore, immunoprecipitation of ILK revealed a decreased interaction with GluR2. The ILK pathway appears to play a significant role in memory and synaptic plasticity impairments in FASD rats. These impairments appear to be mediated by

  18. Genetic targeting of NRXN2 in mice unveils role in excitatory cortical synapse function and social behaviors

    Directory of Open Access Journals (Sweden)

    Gesche eBorn

    2015-02-01

    Full Text Available Human genetics has identified rare copy number variations and deleterious mutations for all neurexin genes (NRXN1-3 in patients with neurodevelopmental diseases, and electrophysiological recordings in animal brains have shown that Nrxns are important for synaptic transmission. While several mouse models for Nrxn1α inactivation have previously been studied for behavioral changes, very little information is available for other variants. Here, we validate that mice lacking Nrxn2α exhibit behavioral abnormalities, characterized by social interaction deficits and increased anxiety-like behavior, which partially overlap, partially differ from Nrxn1α mutant behaviors. Using patch-clamp recordings in Nrxn2α knockout brains, we observe reduced spontaneous transmitter release at excitatory synapses in the neocortex. We also analyse at this cellular level a novel NRXN2 mouse model that carries a combined deletion of Nrxn2α and Nrxn2β. Electrophysiological analysis of this Nrxn2-mutant mouse shows surprisingly similar defects of excitatory release to Nrxn2α, indicating that the β-variant of Nrxn2 has no strong function in basic transmission at these synapses. Inhibitory transmission as well as synapse densities and ultrastructure remain unchanged in the neocortex of both models. Furthermore, at Nrxn2α and Nrxn2-mutant excitatory synapses we find an altered facilitation and N-methyl-D-aspartate receptor (NMDAR function because NMDAR-dependent decay time and NMDAR-mediated responses are reduced. As Nrxn can indirectly be linked to NMDAR via neuroligin and PSD-95, the trans-synaptic nature of this complex may help to explain occurrence of presynaptic and postsynaptic effects. Since excitatory/inhibitory imbalances and impairment of NMDAR function are alledged to have a role in autism and schizophrenia, our results support the idea of a related pathomechanism in these disorders.

  19. Tau deposition drives neuropathological, inflammatory and behavioral abnormalities independently of neuronal loss in a novel mouse model.

    Science.gov (United States)

    Cook, Casey; Kang, Silvia S; Carlomagno, Yari; Lin, Wen-Lang; Yue, Mei; Kurti, Aishe; Shinohara, Mitsuru; Jansen-West, Karen; Perkerson, Emilie; Castanedes-Casey, Monica; Rousseau, Linda; Phillips, Virginia; Bu, Guojun; Dickson, Dennis W; Petrucelli, Leonard; Fryer, John D

    2015-11-01

    Aberrant tau protein accumulation drives neurofibrillary tangle (NFT) formation in several neurodegenerative diseases. Currently, efforts to elucidate pathogenic mechanisms and assess the efficacy of therapeutic targets are limited by constraints of existing models of tauopathy. In order to generate a more versatile mouse model of tauopathy, somatic brain transgenesis was utilized to deliver adeno-associated virus serotype 1 (AAV1) encoding human mutant P301L-tau compared with GFP control. At 6 months of age, we observed widespread human tau expression with concomitant accumulation of hyperphosphorylated and abnormally folded proteinase K resistant tau. However, no overt neuronal loss was observed, though significant abnormalities were noted in the postsynaptic scaffolding protein PSD95. Neurofibrillary pathology was also detected with Gallyas silver stain and Thioflavin-S, and electron microscopy revealed the deposition of closely packed filaments. In addition to classic markers of tauopathy, significant neuroinflammation and extensive gliosis were detected in AAV1-Tau(P301L) mice. This model also recapitulates the behavioral phenotype characteristic of mouse models of tauopathy, including abnormalities in exploration, anxiety, and learning and memory. These findings indicate that biochemical and neuropathological hallmarks of tauopathies are accurately conserved and are independent of cell death in this novel AAV-based model of tauopathy, which offers exceptional versatility and speed in comparison with existing transgenic models. Therefore, we anticipate this approach will facilitate the identification and validation of genetic modifiers of disease, as well as accelerate preclinical assessment of potential therapeutic targets. © The Author 2015. Published by Oxford University Press.

  20. The punctate localization of rat Eag1 K+ channels is conferred by the proximal post-CNBHD region.

    Science.gov (United States)

    Chuang, Chao-Chin; Jow, Guey-Mei; Lin, Huei-Min; Weng, Yu-Han; Hu, Jui-Hsiang; Peng, Yi-Jheng; Chiu, Yi-Chih; Chiu, Mei-Miao; Jeng, Chung-Jiuan

    2014-02-04

    In mammals, Eag K+ channels (KV10) are exclusively expressed in the brain and comprise two isoforms: Eag1 (KV10.1) and Eag2 (KV10.2). Despite their wide presence in various regions of the brain, the functional role of Eag K+ channels remains obscure. Here we address this question by characterizing the subcellular localization of rat Eag1 (rEag1) and rat Eag2 (rEag2) in hippocampal neurons, as well as determining the structural basis underlying their different localization patterns. Immunofluorescence analysis of young and mature hippocampal neurons in culture revealed that endogenous rEag1 and rEag2 K+ channels were present in both the dendrosomatic and the axonal compartments. Only rEag1 channels displayed a punctate immunostaining pattern and showed significant co-localization with PSD-95. Subcellular fractionation analysis further demonstrated a distinct enrichment of rEag1 in the synaptosomal fraction. Over-expression of recombinant GFP-tagged Eag constructs in hippocampal neurons also showed a significant punctate localization of rEag1 channels. To identify the protein region dictating the Eag channel subcellular localization pattern, we generated a variety of different chimeric constructs between rEag1 and rEag2. Quantitative studies of neurons over-expressing these GFP-tagged chimeras indicated that punctate localization was conferred by a segment (A723-R807) within the proximal post-cyclic nucleotide-binding homology domain (post-CNBHD) region in the rEag1 carboxyl terminus. Our findings suggest that Eag1 and Eag2 K+ channels may modulate membrane excitability in both the dendrosomatic and the axonal compartments and that Eag1 may additionally regulate neurotransmitter release and postsynaptic signaling. Furthermore, we present the first evidence showing that the proximal post-CNBHD region seems to govern the Eag K+ channel subcellular localization pattern.

  1. Impaired ILK Function Is Associated with Deficits in Hippocampal Based Memory and Synaptic Plasticity in a FASD Rat Model

    Science.gov (United States)

    Bhattacharya, D.; Dunaway, E. P.; Bhattacharya, S.; Bloemer, J.; Buabeid, M.; Escobar, M.

    2015-01-01

    Fetal Alcohol Spectrum Disorder (FASD) is an umbrella term that encompasses a wide range of anatomical and behavioral problems in children who are exposed to alcohol during the prenatal period. There is no effective treatment for FASD, because of lack of complete characterization of the cellular and molecular mechanisms underlying this condition. Alcohol has been previously characterized to affect integrins and growth factor signaling receptors. Integrin Linked Kinase (ILK) is an effector of integrin and growth-factor signaling which regulates various signaling processes. In FASD, a downstream effector of ILK, Glycogen Synthase Kinase 3β (GSK3β) remains highly active (reduced Ser9 phosphorylation). GSK3β has been known to modulate glutamate receptor trafficking and channel properties. Therefore, we hypothesize that the cognitive deficits accompanying FASD are associated with impairments in the ILK signaling pathway. Pregnant Sprague Dawley rats consumed a “moderate” amount of alcohol throughout gestation, or a calorie-equivalent sucrose solution. Contextual fear conditioning was used to evaluate memory performance in 32–33-day-old pups. Synaptic plasticity was assessed in the Schaffer Collateral pathway, and hippocampal protein lysates were used to evaluate ILK signaling. Alcohol exposed pups showed impaired contextual fear conditioning, as compared to control pups. This reduced memory performance was consistent with decrease in LTP as compared to controls. Hippocampal ILK activity and GSK3β Ser21/9 phosphorylation were significantly lower in alcohol-exposed pups than controls. Increased synaptic expression of GluR2 AMPA receptors was observed with immunoprecipitation of post-synaptic density protein 95 (PSD95). Furthermore, immunoprecipitation of ILK revealed a decreased interaction with GluR2. The ILK pathway appears to play a significant role in memory and synaptic plasticity impairments in FASD rats. These impairments appear to be mediated by reduced

  2. [Effect on nonlinear summation of postsynaptic potentials on the average potential and distribution of interspike intervals of a neuron].

    Science.gov (United States)

    Losev, I S

    1980-01-01

    A probability model of the neuron is considered which uses a simple equivalent electric scheme of the synapse suggesting that characteristic time of conductivity change is much less than the time constant of the membrane tau. The model is characterized by the fact that the distribution of potential jumps depends on the accumulated potential u(t). Formula are obtained for the average value and dispersion of the membrane potential. They coincide with the known formula (1) deduced for the contrary case of slow conductivity changes at tau lambda greater than 1 (lambda - frequency of elementary jumps of conductivity). For tau lambda greater than 1 distribution of probability of interimpulse intervals at arbitrary form of distribution function of jumps F (delta u, u) is described.

  3. Chronic treatment with fluoxetine modulates vascular adrenergic responses by inhibition of pre- and post-synaptic mechanisms.

    Science.gov (United States)

    Pereira, Camila A; Rodrigues, Fernanda L; Ruginsk, Silvia G; Zanotto, Camila Z; Rodrigues, José A; Duarte, Diego A; Costa-Neto, Claudio M; Resstel, Leonardo B; Carneiro, Fernando S; Tostes, Rita C

    2017-04-05

    Fluoxetine, a serotonin reuptake inhibitor (SSRI), has other effects in addition to blocking serotonin reuptake, including changes in the vasomotor tone. Whereas many studies focused on the acute effects of fluoxetine in the vasculature, its chronic effects are still limited. In the present study, we tested the hypothesis that chronic fluoxetine treatment modulates adrenergic vascular responses by interfering with post- and pre-synaptic mechanisms. Wistar rats were treated with vehicle (water) or chronic fluoxetine (10mg/kg/day) for 21 days. Blood pressure (BP) and heart rate were measured. Vascular reactivity was evaluated in perfused mesenteric arterial beds (MAB) and in mesenteric resistance arteries. Protein expression by western blot analysis or immunohistochemistry, β-arrestin recruitment by BRET and calcium influx by FLIPR assay. Fluoxetine treatment decreased phenylephrine (PE)-induced, but not electrical-field stimulation (EFS)-induced vasoconstriction. Fluoxetine-treated rats exhibited increased KCl-induced vasoconstriction, which was abolished by prazosin. Desipramine, an inhibitor of norepinephrine (NA) reuptake, increased EFS-induced vasoconstrictor response in vehicle-treated, but not in fluoxetine-treated rats. Chronic treatment did not alter vascular expression of α1 adrenoceptor, phosphorylation of PKCα or ERK 1/2 and RhoA. On the other hand, vascular contractions to calcium (Ca(2+)) as well as Ca(2+) influx in mesenteric arteries were increased, while intracellular Ca(2+) storage was decreased by the chronic treatment with fluoxetine. In vitro, fluoxetine decreased vascular contractions to PE, EFS and Ca(2+), but did not change β-arrestin activity. In conclusion, chronic treatment with fluoxetine decreases sympathetic-mediated vascular responses by mechanisms that involve inhibition of NA release/reuptake and decreased Ca(2+) stores. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Activity-dependent increases in local oxygen consumption correlate with postsynaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Engelund

    2011-01-01

    and current source density analysis to study real-time Ca(2+) dynamics and transmembrane ionic currents in relation to CMRO(2) in the mouse cerebellar cortex in vivo. We report a direct correlation between CMRO(2) and summed (i.e., the sum of excitatory, negative currents during the whole stimulation period...

  5. Localization of pre- and postsynaptic cholinergic markers in rodent forebrain : A brief history and comparison of rat and mouse

    NARCIS (Netherlands)

    Van der Zee, E. A.; Keijser, J.N.

    2011-01-01

    Rat and mouse models are widely used for studies in cognition and pathophysiology, among others. Here, we sought to determine to what extent these two model species differ for cholinergic and cholinoceptive features. For this purpose, we focused on cholinergic innervation patterns based on choline

  6. The Isolation, Primacy, and Recency Effects Predicted by an Adaptive LTD/LTP Threshold in Postsynaptic Cells

    Science.gov (United States)

    Sikstrom, Sverker

    2006-01-01

    An item that stands out (is isolated) from its context is better remembered than an item consistent with the context. This isolation effect cannot be accounted for by increased attention, because it occurs when the isolated item is presented as the first item, or by impoverished memory of nonisolated items, because the isolated item is better…

  7. Activity-dependent increases in local oxygen consumption correlate with post-synaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Joan

    2011-01-01

    fiber pathway (CF). Blocking stimulus-evoked rises in cytosolic Ca2+ in PCs with the P/Q-type channel blocker ¿-agatoxin-IVA (¿-AGA), or the GABAA receptor agonist muscimol, did not lead to a time-locked reduction in CMRO2, excitatory synaptic or action potential currents. During stimulation, neither...

  8. Activity-dependent increases in local oxygen consumption correlate with postsynaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Engelund

    2011-01-01

    Evoked neural activity correlates strongly with rises in cerebral metabolic rate of oxygen (CMRO(2)) and cerebral blood flow (CBF). Activity-dependent rises in CMRO(2) fluctuate with ATP turnover due to ion pumping. In vitro studies suggest that increases in cytosolic Ca(2+) stimulate oxidative m...

  9. Long-term hippocampal glutamate synapse and astrocyte dysfunctions underlying the altered phenotype induced by adolescent THC treatment in male rats.

    Science.gov (United States)

    Zamberletti, Erica; Gabaglio, Marina; Grilli, Massimo; Prini, Pamela; Catanese, Alberto; Pittaluga, Anna; Marchi, Mario; Rubino, Tiziana; Parolaro, Daniela

    2016-09-01

    Cannabis use has been frequently associated with sex-dependent effects on brain and behavior. We previously demonstrated that adult female rats exposed to delta-9-tetrahydrocannabinol (THC) during adolescence develop long-term alterations in cognitive performances and emotional reactivity, whereas preliminary evidence suggests the presence of a different phenotype in male rats. To thoroughly depict the behavioral phenotype induced by adolescent THC exposure in male rats, we treated adolescent animals with increasing doses of THC twice a day (PND 35-45) and, at adulthood, we performed a battery of behavioral tests to measure affective- and psychotic-like symptoms as well as cognition. Poorer memory performance and psychotic-like behaviors were present after adolescent THC treatment in male rats, without alterations in the emotional component. At cellular level, the expression of the NMDA receptor subunit, GluN2B, as well as the levels of the AMPA subunits, GluA1 and GluA2, were significantly increased in hippocampal post-synaptic fractions from THC-exposed rats compared to controls. Furthermore, increases in the levels of the pre-synaptic marker, synaptophysin, and the post-synaptic marker, PSD95, were also present. Interestingly, KCl-induced [(3)H]D-ASP release from hippocampal synaptosomes, but not gliosomes, was significantly enhanced in THC-treated rats compared to controls. Moreover, in the same brain region, adolescent THC treatment also resulted in a persistent neuroinflammatory state, characterized by increased expression of the astrocyte marker, GFAP, increased levels of the pro-inflammatory markers, TNF-α, iNOS and COX-2, as well as a concomitant reduction of the anti-inflammatory cytokine, IL-10. Notably, none of these alterations was observed in the prefrontal cortex (PFC). Together with our previous findings in females, these data suggest that the sex-dependent detrimental effects induced by adolescent THC exposure on adult behavior may rely on its

  10. Repetitive transcranial magnetic stimulation (rTMS) influences spatial cognition and modulates hippocampal structural synaptic plasticity in aging mice.

    Science.gov (United States)

    Ma, Jun; Zhang, Zhanchi; Kang, Lin; Geng, Dandan; Wang, Yanyong; Wang, Mingwei; Cui, Huixian

    2014-10-01

    Normal aging is characteristic with the gradual decline in cognitive function associated with the progressive reduction of structural and functional plasticity in the hippocampus. Repetitive transcranial magnetic stimulation (rTMS) has developed into a novel neurological and psychiatric tool that can be used to investigate the neurobiology of cognitive function. Recent studies have demonstrated that low-frequency rTMS (≤1Hz) affects synaptic plasticity in rats with vascular dementia (VaD), and it ameliorates the spatial cognitive ability in mice with Aβ1-42-mediated memory deficits, but there are little concerns about the effects of rTMS on normal aging related cognition and synaptic plasticity changes. Thus, the current study investigated the effects of rTMS on spatial memory behavior, neuron and synapse morphology in the hippocampus, and synaptic protein markers and brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) in normal aging mice, to illustrate the mechanisms of rTMS in regulating cognitive capacity. Relative to adult animals, aging caused hippocampal-dependent cognitive impairment, simultaneously inhibited the activation of the BDNF-TrkB signaling pathway, reduced the transcription and expression of synaptic protein markers: synaptophysin (SYN), growth associated protein 43 (GAP43) and post-synaptic density protein 95 (PSD95), as well as decreased synapse density and PSD (post-synaptic density) thickness. Interestingly, rTMS with low intensity (110% average resting motor threshold intensity, 1Hz, LIMS) triggered the activation of BDNF and TrkB, upregulated the level of synaptic protein markers, and increased synapse density and thickened PSD, and further reversed the spatial cognition dysfunction in aging mice. Conversely, high-intensity magnetic stimulation (150% average resting motor threshold intensity, 1Hz, HIMS) appeared to be detrimental, inducing thinning of PSDs, disordered synaptic structure, and a large number of

  11. Overexpression of cypin alters dendrite morphology, single neuron activity, and network properties via distinct mechanisms

    Science.gov (United States)

    Rodríguez, Ana R.; O’Neill, Kate M.; Swiatkowski, Przemyslaw; Patel, Mihir V.; Firestein, Bonnie L.

    2018-02-01

    Objective. This study investigates the effect that overexpression of cytosolic PSD-95 interactor (cypin), a regulator of synaptic PSD-95 protein localization and a core regulator of dendrite branching, exerts on the electrical activity of rat hippocampal neurons and networks. Approach. We cultured rat hippocampal neurons and used lipid-mediated transfection and lentiviral gene transfer to achieve high levels of cypin or cypin mutant (cypinΔPDZ PSD-95 non-binding) expression cellularly and network-wide, respectively. Main results. Our analysis revealed that although overexpression of cypin and cypinΔPDZ increase dendrite numbers and decrease spine density, cypin and cypinΔPDZ distinctly regulate neuronal activity. At the single cell level, cypin promotes decreases in bursting activity while cypinΔPDZ reduces sEPSC frequency and further decreases bursting compared to cypin. At the network level, by using the Fano factor as a measure of spike count variability, cypin overexpression results in an increase in variability of spike count, and this effect is abolished when cypin cannot bind PSD-95. This variability is also dependent on baseline activity levels and on mean spike rate over time. Finally, our spike sorting data show that overexpression of cypin results in a more complex distribution of spike waveforms and that binding to PSD-95 is essential for this complexity. Significance. Our data suggest that dendrite morphology does not play a major role in cypin action on electrical activity.

  12. An X11alpha/FSBP complex represses transcription of the GSK3beta gene promoter.

    LENUS (Irish Health Repository)

    Lau, Kwok-Fai

    2010-08-04

    X11alpha is a neuronal adaptor protein that interacts with the amyloid precursor protein (APP) through a centrally located phosphotyrosine binding domain to inhibit the production of Abeta peptide that is deposited in Alzheimer\\'s disease brains. X11alpha also contains two C-terminal postsynaptic density-95, large discs, zona occludens 1 (PDZ) domains, and we show here that through its PDZ domains, X11alpha interacts with a novel transcription factor, fibrinogen silencer binding protein. Moreover, we show that an X11alpha\\/fibrinogen silencer binding protein complex signals to the nucleus to repress glycogen synthase kinase-3beta promoter activity. Glycogen synthase kinase-3beta is a favoured candidate kinase for phosphorylating tau in Alzheimer\\'s disease. Our findings show a new function for X11alpha that may impact on Alzheimer\\'s disease pathogenesis.

  13. Targeting of the Dopamine Transporter Involves Discrete Epitopes in the Distal C Terminus But Does Not Require Canonical PDZ Domain Interactions

    DEFF Research Database (Denmark)

    Bjerggaard(Vægter), Christian; Fog, Jacob Ulrik; Hastrup, Hanne

    2004-01-01

    -adrenergic receptor, did not disrupt plasma membrane targeting. Moreover, the addition of an alanine to the hDAT C terminus (+Ala), resulting in an LKVA termination sequence, or substitution of LKV with alanines (3xAla_618-620) prevented neither plasma membrane targeting nor targeting into sprouting neurites...... are indispensable for proper targeting, PDZ domain interactions are not required. By progressive substitutions with beta2-adrenergic receptor sequence, and by triple-alanine substitutions in the hDAT C terminus, we examined the importance of epitopes preceding the LKV motif. Substitution of RHW(615......The human dopamine transporter (hDAT) contains a C-terminal type 2 PDZ (postsynaptic density 95/Discs large/zona occludens 1) domain-binding motif (LKV) known to interact with PDZ domain proteins such as PICK1 (protein interacting with C-kinase 1). As reported previously, we found that, after...

  14. Surface targeting of the dopamine transporter involves discrete epitopes in the distal C terminus but does not require canonical PDZ domain interactions

    DEFF Research Database (Denmark)

    Bjerggaard, Christian; Fog, Jacob U; Hastrup, Hanne

    2004-01-01

    -adrenergic receptor, did not disrupt plasma membrane targeting. Moreover, the addition of an alanine to the hDAT C terminus (+Ala), resulting in an LKVA termination sequence, or substitution of LKV with alanines (3xAla_618-620) prevented neither plasma membrane targeting nor targeting into sprouting neurites...... are indispensable for proper targeting, PDZ domain interactions are not required. By progressive substitutions with beta2-adrenergic receptor sequence, and by triple-alanine substitutions in the hDAT C terminus, we examined the importance of epitopes preceding the LKV motif. Substitution of RHW(615......The human dopamine transporter (hDAT) contains a C-terminal type 2 PDZ (postsynaptic density 95/Discs large/zona occludens 1) domain-binding motif (LKV) known to interact with PDZ domain proteins such as PICK1 (protein interacting with C-kinase 1). As reported previously, we found that, after...

  15. Intracellular cholesterol-binding proteins enhance HDL-mediated cholesterol uptake in cultured primary mouse hepatocytes

    Science.gov (United States)

    Storey, Stephen M.; McIntosh, Avery L.; Huang, Huan; Landrock, Kerstin K.; Martin, Gregory G.; Landrock, Danilo; Payne, H. Ross; Atshaves, Barbara P.; Kier, Ann B.

    2012-01-01

    A major gap in our knowledge of rapid hepatic HDL cholesterol clearance is the role of key intracellular factors that influence this process. Although the reverse cholesterol transport pathway targets HDL to the liver for net elimination of free cholesterol from the body, molecular details governing cholesterol uptake into hepatocytes are not completely understood. Therefore, the effects of sterol carrier protein (SCP)-2 and liver fatty acid-binding protein (L-FABP), high-affinity cholesterol-binding proteins present in hepatocyte cytosol, on HDL-mediated free cholesterol uptake were examined using gene-targeted mouse models, cultured primary hepatocytes, and 22-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol). While SCP-2 overexpression enhanced NBD-cholesterol uptake, counterintuitively, SCP-2/SCP-x gene ablation also 1) enhanced the rapid molecular phase of free sterol uptake detectable in cholesterol and 2) differentially enhanced free cholesterol uptake mediated by the HDL3, rather than the HDL2, subfraction. The increased HDL free cholesterol uptake was not due to increased expression or distribution of the HDL receptor [scavenger receptor B1 (SRB1)], proteins regulating SRB1 [postsynaptic density protein (PSD-95)/Drosophila disk large tumor suppressor (dlg)/tight junction protein (ZO1) and 17-kDa membrane-associated protein], or other intracellular cholesterol trafficking proteins (steroidogenic acute response protein D, Niemann Pick C, and oxysterol-binding protein-related proteins). However, expression of L-FABP, the single most prevalent hepatic cytosolic protein that binds cholesterol, was upregulated twofold in SCP-2/SCP-x null hepatocytes. Double-immunogold electron microscopy detected L-FABP sufficiently close to SRB1 for direct interaction, similar to SCP-2. These data suggest a role for L-FABP in HDL cholesterol uptake, a finding confirmed with SCP-2/SCP-x/L-FABP null mice and hepatocytes. Taken together

  16. Maternal deprivation effects on brain plasticity and recognition memory in adolescent male and female rats.

    Science.gov (United States)

    Marco, Eva M; Valero, Manuel; de la Serna, Oscar; Aisa, Barbara; Borcel, Erika; Ramirez, Maria Javier; Viveros, María-Paz

    2013-05-01

    Data from both human and animal studies suggest that exposure to stressful life events at neonatal stages may increase the risk of psychopathology at adulthood. In particular, early maternal deprivation, 24 h at postnatal day (pnd) 9, has been associated with persistent neurobehavioural changes similar to those present in developmental psychopathologies such as depression and schizophrenic-related disorders. Most neuropsychiatric disorders first appear during adolescence, however, the effects of MD on adolescent animals' brain and behaviour have been scarcely explored. In the present study, we aimed to investigate the emotional and cognitive consequences of MD in adolescent male and female rats, as well as possible underlying neurobiological mechanisms within frontal cortex and hippocampus. Animals were exposed to a battery of behavioural tasks, from pnd 35 to 42, to evaluate cognitive [spontaneous alternation task (SAT) and novel object test (NOT)] and anxiety-related responses [elevated plus maze (EPM)] during adolescence. Changes in neuronal and glial cells, alterations in synaptic plasticity as well as modifications in cannabinoid receptor expression were investigated in a parallel group of control and adolescent (pnd 40) male and female animals. Notably, MD induced a significant impairment in recognition memory exclusively among females. A generalized decrease in NeuN expression was found in MD animals, together with an increase in hippocampal glial fibrillar acidic protein (GFAP) expression exclusively among MD adolescent males. In addition, MD induced in the frontal cortex and hippocampus of male and female adolescent rats a significant reduction in brain derived neurotrophic factor (BDNF) and postsynaptic density (PSD95) levels, together with a decrease in synaptophysin in frontal cortex and neural cell adhesion molecule (NCAM) in hippocampus. MD induced, in animals of both sexes, a significant reduction in CB1R expression, but an increase in CB2R that was

  17. Striatal Synaptosomes from Hdh140Q/140Q Knock-in Mice have Altered Protein Levels, Novel Sites of Methionine Oxidation, and Excess Glutamate Release after Stimulation

    Science.gov (United States)

    Valencia, Antonio; Sapp, Ellen; Kimm, Jeffrey S.; McClory, Hollis; Ansong, Kwadwo A.; Yohrling, George; Kwak, Seung; Kegel, Kimberly B.; Green, Karin M.; Shaffer, Scott A.; Aronin, Neil; DiFiglia, Marian

    2014-01-01

    Background: Synaptic connections are disrupted in patients with Huntington’s disease (HD). Synaptosomes from postmortem brain are ideal for synaptic function studies because they are enriched in pre- and post-synaptic proteins important in vesicle fusion, vesicle release, and neurotransmitter receptor activation. Objective: To examine striatal synaptosomes from 3, 6 and 12 month old WT and Hdh140Q/140Q knock-in mice for levels of synaptic proteins, methionine oxidation, and glutamate release. Methods: We used Western blot analysis, glutamate release assays, and liquid chromatography tandem mass spectrometry (LC-MS/MS). Results: Striatal synaptosomes of 6 month old Hdh140Q/140Q mice had less DARPP32, syntaxin 1 and calmodulin compared to WT. Striatal synaptosomes of 12 month old Hdh140Q/140Q mice had lower levels of DARPP32, alpha actinin, HAP40, Na+/K+-ATPase, PSD95, SNAP-25, TrkA and VAMP1, VGlut1 and VGlut2, increased levels of VAMP2, and modifications in actin and calmodulin compared to WT. More glutamate released from vesicles of depolarized striatal synaptosomes of 6 month old Hdh140Q/140Q than from age matched WT mice but there was no difference in glutamate release in synaptosomes of 3 and 12 month old WT and Hdh140Q/140Q mice. LC-MS/MS of 6 month old Hdh140Q/140Q mice striatal synaptosomes revealed that about 4% of total proteins detected (>600 detected) had novel sites of methionine oxidation including proteins involved with vesicle fusion, trafficking, and neurotransmitter function (synaptophysin, synapsin 2, syntaxin 1, calmodulin, cytoplasmic actin 2, neurofilament, and tubulin). Altered protein levels and novel methionine oxidations were also seen in cortical synaptosomes of 12 month old Hdh140Q/140Q mice. Conclusions: Findings provide support for early synaptic dysfunction in Hdh140Q/140Q knock-in mice arising from altered protein levels, oxidative damage, and impaired glutamate neurotransmission and suggest that study of synaptosomes could be of

  18. Hydrogen Sulfide Ameliorates Homocysteine-Induced Alzheimer's Disease-Like Pathology, Blood-Brain Barrier Disruption, and Synaptic Disorder.

    Science.gov (United States)

    Kamat, Pradip K; Kyles, Philip; Kalani, Anuradha; Tyagi, Neetu

    2016-05-01

    Elevated plasma total homocysteine (Hcy) level is associated with an increased risk of Alzheimer's disease (AD). During transsulfuration pathways, Hcy is metabolized into hydrogen sulfide (H2S), which is a synaptic modulator, as well as a neuro-protective agent. However, the role of hydrogen sulfide, as well as N-methyl-D-aspartate receptor (NMDAR) activation, in hyperhomocysteinemia (HHcy) induced blood-brain barrier (BBB) disruption and synaptic dysfunction, leading to AD pathology is not clear. Therefore, we hypothesized that the inhibition of neuronal NMDA-R by H2S and MK801 mitigate the Hcy-induced BBB disruption and synapse dysfunction, in part by decreasing neuronal matrix degradation. Hcy intracerebral (IC) treatment significantly impaired cerebral blood flow (CBF), and cerebral circulation and memory function. Hcy treatment also decreases the expression of cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE) in the brain along with increased expression of NMDA-R (NR1) and synaptosomal Ca(2+) indicating excitotoxicity. Additionally, we found that Hcy treatment increased protein and mRNA expression of intracellular adhesion molecule 1 (ICAM-1), matrix metalloproteinase (MMP)-2, and MMP-9 and also increased MMP-2 and MMP-9 activity in the brain. The increased expression of ICAM-1, glial fibrillary acidic protein (GFAP), and the decreased expression of vascular endothelial (VE)-cadherin and claudin-5 indicates BBB disruption and vascular inflammation. Moreover, we also found decreased expression of microtubule-associated protein 2 (MAP-2), postsynaptic density protein 95 (PSD-95), synapse-associated protein 97 (SAP-97), synaptosomal-associated protein 25 (SNAP-25), synaptophysin, and brain-derived neurotrophic factor (BDNF) showing synapse dysfunction in the hippocampus. Furthermore, NaHS and MK801 treatment ameliorates BBB disruption, CBF, and synapse functions in the mice brain. These results demonstrate a neuro-protective effect of H2S over Hcy

  19. Repairing the Brain by SCF+G-CSF Treatment at 6 Months Postexperimental Stroke

    Directory of Open Access Journals (Sweden)

    Lili Cui

    2016-06-01

    Full Text Available Stroke, a leading cause of adult disability in the world, is a severe medical condition with limited treatment. Physical therapy, the only treatment available for stroke rehabilitation, appears to be effective within 6 months post-stroke. Here, we have mechanistically determined the efficacy of combined two hematopoietic growth factors, stem cell factor (SCF and granulocyte-colony stimulating factor (G-CSF; SCF + G-CSF, in brain repair 6 months after cortical infarct induction in the transgenic mice carrying yellow fluorescent protein in Layer V pyramidal neurons (Thy1-YFP-H. Using a combination of live brain imaging, whole brain imaging, molecular manipulation, synaptic and vascular assessments, and motor function examination, we found that SCF + G-CSF promoted mushroom spine formation, enlarged postsynaptic membrane size, and increased postsynaptic density-95 accumulation and blood vessel density in the peri-infarct cavity cortex; and that SCF + G-CSF treatment improved motor functional recovery. The SCF + G-CSF-enhanced motor functional recovery was dependent on the synaptic and vascular regeneration in the peri-infarct cavity cortex. These data suggest that a stroke-damaged brain is repairable by SCF + G-CSF even 6 months after the lesion occurs. This study provides novel insights into the development of new restorative strategies for stroke recovery.

  20. Repairing the Brain by SCF+G-CSF Treatment at 6 Months Postexperimental Stroke

    Science.gov (United States)

    Cui, Lili; Wang, Dandan; McGillis, Sandra; Kyle, Michele

    2016-01-01

    Stroke, a leading cause of adult disability in the world, is a severe medical condition with limited treatment. Physical therapy, the only treatment available for stroke rehabilitation, appears to be effective within 6 months post-stroke. Here, we have mechanistically determined the efficacy of combined two hematopoietic growth factors, stem cell factor (SCF) and granulocyte-colony stimulating factor (G-CSF; SCF + G-CSF), in brain repair 6 months after cortical infarct induction in the transgenic mice carrying yellow fluorescent protein in Layer V pyramidal neurons (Thy1-YFP-H). Using a combination of live brain imaging, whole brain imaging, molecular manipulation, synaptic and vascular assessments, and motor function examination, we found that SCF + G-CSF promoted mushroom spine formation, enlarged postsynaptic membrane size, and increased postsynaptic density-95 accumulation and blood vessel density in the peri-infarct cavity cortex; and that SCF + G-CSF treatment improved motor functional recovery. The SCF + G-CSF-enhanced motor functional recovery was dependent on the synaptic and vascular regeneration in the peri-infarct cavity cortex. These data suggest that a stroke-damaged brain is repairable by SCF + G-CSF even 6 months after the lesion occurs. This study provides novel insights into the development of new restorative strategies for stroke recovery. PMID:27511907

  1. Repairing the Brain by SCF+G-CSF Treatment at 6 Months Postexperimental Stroke: Mechanistic Determination of the Causal Link Between Neurovascular Regeneration and Motor Functional Recovery.

    Science.gov (United States)

    Cui, Lili; Wang, Dandan; McGillis, Sandra; Kyle, Michele; Zhao, Li-Ru

    2016-06-01

    Stroke, a leading cause of adult disability in the world, is a severe medical condition with limited treatment. Physical therapy, the only treatment available for stroke rehabilitation, appears to be effective within 6 months post-stroke. Here, we have mechanistically determined the efficacy of combined two hematopoietic growth factors, stem cell factor (SCF) and granulocyte-colony stimulating factor (G-CSF; SCF + G-CSF), in brain repair 6 months after cortical infarct induction in the transgenic mice carrying yellow fluorescent protein in Layer V pyramidal neurons (Thy1-YFP-H). Using a combination of live brain imaging, whole brain imaging, molecular manipulation, synaptic and vascular assessments, and motor function examination, we found that SCF + G-CSF promoted mushroom spine formation, enlarged postsynaptic membrane size, and increased postsynaptic density-95 accumulation and blood vessel density in the peri-infarct cavity cortex; and that SCF + G-CSF treatment improved motor functional recovery. The SCF + G-CSF-enhanced motor functional recovery was dependent on the synaptic and vascular regeneration in the peri-infarct cavity cortex. These data suggest that a stroke-damaged brain is repairable by SCF + G-CSF even 6 months after the lesion occurs. This study provides novel insights into the development of new restorative strategies for stroke recovery. © The Author(s) 2016.

  2. RanBP9 overexpression accelerates loss of pre and postsynaptic proteins in the APΔE9 transgenic mouse brain.

    Science.gov (United States)

    Wang, Hongjie; Wang, Ruizhi; Xu, Shaohua; Lakshmana, Madepalli K

    2014-01-01

    There is now compelling evidence that the neurodegenerative process in Alzheimer's disease (AD) begins in synapses. Loss of synaptic proteins and functional synapses in the amyloid precursor protein (APP) transgenic mouse models of AD is well established. However, what is the earliest age at which such loss of synapses occurs, and whether known markers of AD progression accelerate functional deficits is completely unknown. We previously showed that RanBP9 overexpression leads to robustly increased amyloid β peptide (Aβ) generation leading to enhanced amyloid plaque burden in a mouse model of AD. In this study we compared synaptic protein levels among four genotypes of mice, i.e., RanBP9 single transgenic (Ran), APΔE9 double transgenic (Dbl), APΔE9/RanBP9 triple transgenic (Tpl) and wild-type (WT) controls. We found significant reductions in the levels of synaptic proteins in both cortex and hippocampus of 5- and 6-months-old but not 3- or 4-months-old mice. Specifically, at 5-months of age, rab3A was reduced in the triple transgenic mice only in the cortex by 25% (pproteins in the mouse brain.

  3. Postsynaptic α1-Adrenergic Vasoconstriction Is Impaired in Young Patients With Vasovagal Syncope and Is Corrected by Nitric Oxide Synthase Inhibition.

    Science.gov (United States)

    Stewart, Julian M; Suggs, Melissa; Merchant, Sana; Sutton, Richard; Terilli, Courtney; Visintainer, Paul; Medow, Marvin S

    2016-08-01

    Syncope is a sudden transient loss of consciousness and postural tone with spontaneous recovery; the most common form is vasovagal syncope (VVS). During VVS, gravitational pooling excessively reduces central blood volume and cardiac output. In VVS, as in hemorrhage, impaired adrenergic vasoconstriction and venoconstriction result in hypotension. We hypothesized that impaired adrenergic responsiveness because of excess nitric oxide can be reversed by reducing nitric oxide. We recorded cardiopulmonary dynamics in supine syncope patients and healthy volunteers (aged 15-27 years) challenged with a dose-response using the α1-agonist phenylephrine (PE), with and without the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine, monoacetate salt (L-NMMA). Systolic and diastolic pressures among control and VVS were the same, although they increased after L-NMMA and saline+PE (volume and pressor control for L-NMMA). Heart rate was significantly reduced by L-NMMA (Pnitric oxide synthase inhibition, demonstrated with our use of L-NMMA. © 2016 American Heart Association, Inc.

  4. Ultrastructural evidence for pre- and postsynaptic localization of Cav1.2 L-type Ca2+ channels in the rat hippocampus.

    Science.gov (United States)

    Tippens, Alyssa L; Pare, Jean-Francois; Langwieser, Nicole; Moosmang, Sven; Milner, Teresa A; Smith, Yoland; Lee, Amy

    2008-02-01

    In the hippocampal formation, Ca(v)1.2 (L-type) voltage-gated Ca(2+) channels mediate Ca(2+) signals that can trigger long-term alterations in synaptic efficacy underlying learning and memory. Immunocytochemical studies indicate that Ca(v)1.2 channels are localized mainly in the soma and proximal dendrites of hippocampal pyramidal neurons, but electrophysiological data suggest a broader distribution of these channels. To define the subcellular substrates underlying Ca(v)1.2 Ca(2+) signals, we analyzed the localization of Ca(v)1.2 in the hippocampal formation by using antibodies against the pore-forming alpha(1)-subunit of Ca(v)1.2 (alpha(1)1.2). By light microscopy, alpha(1)1.2-like immunoreactivity (alpha(1)1.2-IR) was detected in pyramidal cell soma and dendritic fields of areas CA1-CA3 and in granule cell soma and fibers in the dentate gyrus. At the electron microscopic level, alpha(1)1.2-IR was localized in dendrites, but also in axons, axon terminals, and glial processes in all hippocampal subfields. Plasmalemmal immunogold particles representing alpha(1)1.2-IR were more significant for small- than large-caliber dendrites and were largely associated with extrasynaptic regions in dendritic spines and axon terminals. These findings provide the first detailed ultrastructural analysis of Ca(v)1.2 localization in the brain and support functionally diverse roles of these channels in the hippocampal formation. (c) 2007 Wiley-Liss, Inc.

  5. Input specificity and dependence of spike timing-dependent plasticity on preceding postsynaptic activity at unitary connections between neocortical layer 2/3 pyramidal cells

    NARCIS (Netherlands)

    Zilberter, M.; Holmgren, C.D.; Shemer, I.; Silberberg, G.; Grillner, S.; Harkany, T.; Zilberter, Y.

    2009-01-01

    Layer 2/3 (L2/3) pyramidal cells receive excitatory afferent input both from neighbouring pyramidal cells and from cortical and subcortical regions. The efficacy of these excitatory synaptic inputs is modulated by spike timing-dependent plasticity (STDP). Here we report that synaptic connections

  6. Age-related changes in functional postsynaptic nAChR subunits in neurons of the laterodorsal tegmental nucleus, a nucleus important in drug addiction

    DEFF Research Database (Denmark)

    Christensen, Mark Holm; Kohlmeier, Kristi Anne

    2016-01-01

    The earlier an individual initiates cigarette smoking, the higher the likelihood of development of dependency to nicotine, the addictive ingredient in cigarettes. One possible mechanism underlying this higher addiction liability is an ontogenetically differential cellular response induced...... the laterodorsal tegmentum (LDT), a nucleus importantly involved in drug addiction associated behaviours, across two periods of ontogeny in which nicotine-mediated excitatory responses were shown to depend on age. To this end, whole-cell patch-clamp recordings in mouse brain slices from identified LDT neurons...

  7. Pharmacological isolation of postsynaptic currents mediated by NR2A- and NR2B-containing NMDA receptors in the anterior cingulate cortex

    Directory of Open Access Journals (Sweden)

    Cao Xiaoyan

    2007-04-01

    Full Text Available Abstract NMDA receptors (NMDARs are involved in excitatory synaptic transmission and plasticity associated with a variety of brain functions, from memory formation to chronic pain. Subunit-selective antagonists for NMDARs provide powerful tools to dissect NMDAR functions in neuronal activities. Recently developed antagonist for NR2A-containing receptors, NVP-AAM007, triggered debates on its selectivity and involvement of the NMDAR subunits in bi-directional synaptic plasticity. Here, we re-examined the pharmacological properties of NMDARs in the anterior cingulate cortex (ACC using NVP-AAM007 as well as ifenprodil, a selective antagonist for NR2B-containing NMDARs. By alternating sequence of drug application and examining different concentrations of NVP-AAM007, we found that the presence of NVP-AAM007 did not significantly affect the effect of ifenprodil on NMDAR-mediated EPSCs. These results suggest that NVP-AAM007 shows great preference for NR2A subunit and could be used as a selective antagonist for NR2A-containing NMDARs in the ACC.

  8. Domain Modeling: NP_542414.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_542414.1 chr4 Solution structure of PSD-95 PDZ12 complexed with cypin peptide p2ka9a_ chr4/NP_542414....1/NP_542414.1_holo_1368-1588.pdb blast 1794S,1795E,1796K,1797G,1799L,1800G,1801F,1802T,

  9. Prenatal music stimulation facilitates the postnatal functional ...

    Indian Academy of Sciences (India)

    2014-01-27

    Jan 27, 2014 ... inter-hemispheric and gender-based difference in expression was also found in all groups. ... of music discrimination is present even in species that are ..... gender. However, the female chicks had significantly higher synaptophysin and PSD-95 expression in comparison to males at all ages as evident by ...

  10. A fluorescence polarization based screening assay for identification of small molecule inhibitors of the PICK1 PDZ domain

    DEFF Research Database (Denmark)

    Thorsen, Thor S; Madsen, Kenneth L; Dyhring, Tino

    2011-01-01

    PDZ (PSD-95/Discs-large/ZO-1 homology) domains represent putative targets in several diseases including cancer, stroke, addiction and neuropathic pain. Here we describe the application of a simple and fast screening assay based on fluorescence polarization (FP) to identify inhibitors of the PDZ...

  11. A C-terminal PDZ domain-binding sequence is required for striatal distribution of the dopamine transporter

    DEFF Research Database (Denmark)

    Rickhag, Karl Mattias; Hansen, Freja Herborg; Sørensen, Gunnar

    2013-01-01

    The dopamine transporter mediates reuptake of dopamine from the synaptic cleft. The cellular mechanisms controlling dopamine transporter levels in striatal nerve terminals remain poorly understood. The dopamine transporters contain a C-terminal PDZ (PSD-95/Discs-large/ZO-1) domain-binding sequence...

  12. Protein interacting with C kinase 1 (PICK1) reduces reinsertion rates of interaction partners sorted to Rab11-dependent slow recycling pathway

    DEFF Research Database (Denmark)

    Madsen, Kenneth Lindegaard; Thorsen, Thor Seneca; Rahbek-Clemmensen, Troels

    2012-01-01

    The scaffolding protein PICK1 (protein interacting with C kinase 1) contains an N-terminal PSD-95/Discs large/ZO-1 (PDZ) domain and a central lipid-binding Bin/amphiphysin/Rvs (BAR) domain. PICK1 is thought to regulate trafficking of its PDZ binding partners but different and even opposing...

  13. Membrane localization is critical for activation of the PICK1 BAR domain

    DEFF Research Database (Denmark)

    Madsen, Kenneth L; Eriksen, Jacob; Milan-Lobo, Laura

    2008-01-01

    The PSD-95/Discs-large/ZO-1 homology (PDZ) domain protein, protein interacting with C kinase 1 (PICK1) contains a C-terminal Bin/amphiphysin/Rvs (BAR) domain mediating recognition of curved membranes; however, the molecular mechanisms controlling the activity of this domain are poorly understood...

  14. An allosteric intramolecular PDZ-PDZ interaction modulates PTP-BL PDZ2 binding specificity

    NARCIS (Netherlands)

    Berk, L.C.J. van den; Landi, E.; Walma, T.; Vuister, G.W.; Dente, L.; Hendriks, W.J.A.J.

    2007-01-01

    PDZ (acronym of the synapse-associated protein PSD-95/SAP90, the septate junction protein Discs-large, and the tight junction protein ZO-1) domains are abundant small globular protein interaction domains that mainly recognize the carboxyl termini of their target proteins. Detailed knowledge on PDZ

  15. An Allosteric Intramolecular PDZ-PDZ Interaction Modulates PTP-BL PDZ2 Binding Specificity

    NARCIS (Netherlands)

    Berk, L.C.; Landi, E.; Walma, T.; Vuister, G.W.; Dente, L.; Hendriks, W.J.A.J.

    2007-01-01

    PDZ (acronym of the synapse-associated protein PSD-95/SAP90, the septate junction protein Discs-large, and the tight junction protein ZO-1) domains are abundant small globular protein interaction domains that mainly recognize the carboxyl termini of their target proteins. Detailed knowledge on PDZ

  16. Early natural stimulation through environmental enrichment accelerates neuronal development in the mouse dentate gyrus.

    Directory of Open Access Journals (Sweden)

    Na Liu

    Full Text Available The dentate gyrus is the primary afferent into the hippocampal formation, with important functions in learning and memory. Granule cells, the principle neuronal type in the dentate gyrus, are mostly formed postnatally, in a process that continues into adulthood. External stimuli, including environmental enrichment, voluntary exercise and learning, have been shown to significantly accelerate the generation and maturation of dentate granule cells in adult rodents. Whether, and to what extent, such environmental stimuli regulate the development and maturation of dentate granule cells during early postnatal development is largely unknown. Furthermore, whether natural stimuli affect the synaptic properties of granule cells had been investigated neither in newborn neurons of the adult nor during early development. To examine the effect of natural sensory stimulation on the dentate gyrus, we reared newborn mice in an enriched environment (EE. Using immunohistochemistry, we showed that dentate granule cells from EE-reared mice exhibited earlier morphological maturation, manifested as faster peaking of doublecortin expression and elevated expression of mature neuronal markers (including NeuN, calbindin and MAP2 at the end of the second postnatal week. Also at the end of the second postnatal week, we found increased density of dendritic spines across the entire dentate gyrus, together with elevated levels of postsynaptic scaffold (post-synaptic density 95 and receptor proteins (GluR2 and GABA(ARγ2 of excitatory and inhibitory synapses. Furthermore, dentate granule cells of P14 EE-reared mice had lower input resistances and increased glutamatergic and GABAergic synaptic inputs. Together, our results demonstrate that EE-rearing promotes morphological and electrophysiological maturation of dentate granule cells, underscoring the importance of natural environmental stimulation on development of the dentate gyrus.

  17. Analysis of Proteins That Rapidly Change Upon Mechanistic/Mammalian Target of Rapamycin Complex 1 (mTORC1) Repression Identifies Parkinson Protein 7 (PARK7) as a Novel Protein Aberrantly Expressed in Tuberous Sclerosis Complex (TSC).

    Science.gov (United States)

    Niere, Farr; Namjoshi, Sanjeev; Song, Ehwang; Dilly, Geoffrey A; Schoenhard, Grant; Zemelman, Boris V; Mechref, Yehia; Raab-Graham, Kimberly F

    2016-02-01

    with the postsynaptic marker postsynaptic density-95. Our work offers a comprehensive view of mTORC1 and its role in regulating regional protein expression in normal and diseased states. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Analysis of Proteins That Rapidly Change Upon Mechanistic/Mammalian Target of Rapamycin Complex 1 (mTORC1) Repression Identifies Parkinson Protein 7 (PARK7) as a Novel Protein Aberrantly Expressed in Tuberous Sclerosis Complex (TSC)*

    Science.gov (United States)

    Niere, Farr; Namjoshi, Sanjeev; Song, Ehwang; Dilly, Geoffrey A.; Schoenhard, Grant; Zemelman, Boris V.; Mechref, Yehia; Raab-Graham, Kimberly F.

    2016-01-01

    colocalizes with the postsynaptic marker postsynaptic density-95. Our work offers a comprehensive view of mTORC1 and its role in regulating regional protein expression in normal and diseased states. PMID:26419955

  19. Molecular determinants of NMDA receptor internalization.

    Science.gov (United States)

    Roche, K W; Standley, S; McCallum, J; Dune Ly, C; Ehlers, M D; Wenthold, R J

    2001-08-01

    Although synaptic AMPA receptors have been shown to rapidly internalize, synaptic NMDA receptors are reported to be static. It is not certain whether NMDA receptor stability at synaptic sites is an inherent property of the receptor, or is due to stabilization by scaffolding proteins. In this study, we demonstrate that NMDA receptors are internalized in both heterologous cells and neurons, and we define an internalization motif, YEKL, on the distal C-terminus of NR2B. In addition, we show that the synaptic protein PSD-95 inhibits NR2B-mediated internalization, and that deletion of the PDZ-binding domain of NR2B increases internalization in neurons. This suggests an involvement for PSD-95 in NMDA receptor regulation and an explanation for NMDA receptor stability at synaptic sites.

  20. Caffeine and modafinil given during 48 h sleep deprivation modulate object recognition memory and synaptic proteins in the hippocampus of the rat.

    Science.gov (United States)

    Wadhwa, M; Sahu, S; Kumari, P; Kauser, H; Ray, K; Panjwani, U

    2015-11-01

    We aimed to evaluate the effect of caffeine/modafinil on sleep deprivation (SD) induced alterations in recognition memory and synaptic proteins. The data revealed a beneficial effect of caffeine/modafinil against deficit in the familiar object retrieval performance and object exploration ratio after 48 h SD. Caffeine treatment prevented the SD induced down-regulation of synaptophysin and synapsin I proteins with no change in PSD-95 protein in hippocampus. However, modafinil administration improved the down-regulation of synaptophysin, synapsin I and PSD-95 proteins in hippocampus. Hence, caffeine/modafinil can serve as counter measures in amelioration of SD induced consequences at behavioural and protein levels. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Beta 2-adrenergic receptor activation enhances neurogenesis in Alzheimer′s disease mice

    Directory of Open Access Journals (Sweden)

    Gao-shang Chai

    2016-01-01

    Full Text Available Impaired hippocampal neurogenesis is one of the early pathological features of Alzheimer′s disease. Enhancing adult hippocampal neurogenesis has been pursued as a potential therapeutic strategy for Alzheimer′s disease. Recent studies have demonstrated that environmental novelty activates β2 -adrenergic signaling and prevents the memory impairment induced by amyloid-β oligomers. Here, we hypothesized that β2 -adrenoceptor activation would enhance neurogenesis and ameliorate memory deficits in Alzheimer′s disease. To test this hypothesis, we investigated the effects and mechanisms of action of β2 -adrenoceptor activation on neurogenesis and memory in amyloid precursor protein/presenilin 1 (APP/PS1 mice using the agonist clenbuterol (intraperitoneal injection, 2 mg/kg. We found that β2 -adrenoceptor activation enhanced hippocampal neurogenesis, ameliorated memory deficits, and increased dendritic branching and the density of dendritic spines. These effects were associated with the upregulation of postsynaptic density 95, synapsin 1 and synaptophysin in APP/PS1 mice. Furthermore, β2 -adrenoceptor activation decreased cerebral amyloid plaques by decreasing APP phosphorylation at Thr668. These findings suggest that β2 -adrenoceptor activation enhances neurogenesis and ameliorates memory deficits in APP/PS1 mice.

  2. NHERF1 regulates actin cytoskeleton organization through modulation of α-actinin-4 stability.

    Science.gov (United States)

    Sun, Licui; Zheng, Junfang; Wang, Qiqi; Song, Ran; Liu, Hua; Meng, Ran; Tao, Tao; Si, Yang; Jiang, Wenguo; He, Junqi

    2016-02-01

    The actin cytoskeleton is composed of a highly dynamic network of filamentous proteins, yet the molecular mechanism that regulates its organization and remodeling remains elusive. In this study, Na(+)/H(+) exchanger regulatory factor (NHERF)-1 loss-of-function and gain-of-function experiments reveal that polymerized actin cytoskeleton (F-actin) in HeLa cells is disorganized by NHERF1, whereas actin protein expression levels exhibit no detectable change. To elucidate the molecular mechanism underlying actin cytoskeleton disorganization by NHERF1, a combined 2-dimensional electrophoresis-matrix-assisted laser desorption/ionization-time of flight mass spectrometry approach was used to screen for proteins regulated by NHERF1 in HeLa cells. α-Actinin-4, an actin cross-linking protein, was identified. Glutathione S-transferase pull-down and coimmunoprecipitation studies showed the α-actinin-4 carboxyl-terminal region specifically interacted with the NHERF1 postsynaptic density 95/disc-large/zona occludens-1 domain. The NHERF1/α-actinin-4 interaction increased α-actinin-4 ubiquitination and decreased its expression levels, resulting in actin cytoskeleton disassembly. Our study identified α-actinin-4 as a novel NHERF1 interaction partner and provided new insights into the regulatory mechanism of the actin cytoskeleton by NHERF1. © FASEB.

  3. Is it possible to improve memory function by upregulation of the cholesterol 24S-hydroxylase (CYP46A1 in the brain?

    Directory of Open Access Journals (Sweden)

    Silvia Maioli

    Full Text Available We previously described a heterozygous mouse model overexpressing human HA-tagged 24S-hydroxylase (CYP46A1 utilizing a ubiquitous expression vector. In this study, we generated homozygotes of these mice with circulating levels of 24OH 30-60% higher than the heterozygotes. Female homozygous CYP46A1 transgenic mice, aged 15 months, showed an improvement in spatial memory in the Morris water maze test as compared to the wild type mice. The levels of N-Methyl-D-Aspartate receptor 1, phosphorylated-N-Methyl-D-Aspartate receptor 2A, postsynaptic density 95, synapsin-1 and synapthophysin were significantly increased in the hippocampus of the CYP46A1 transgenic mice as compared to the controls. The levels of lanosterol in the brain of the CYP46A1 transgenic mice were significantly increased, consistent with a higher synthesis of cholesterol. Our results are discussed in relation to the hypothesis that the flux in the mevalonate pathway in the brain is of importance in cognitive functions.

  4. The NHERF1 PDZ2 domain regulates PKA-RhoA-p38-mediated NHE1 activation and invasion in breast tumor cells.

    Science.gov (United States)

    Cardone, Rosa A; Bellizzi, Antonia; Busco, Giovanni; Weinman, Edward J; Dell'Aquila, Maria E; Casavola, Valeria; Azzariti, Amalia; Mangia, Anita; Paradiso, Angelo; Reshkin, Stephan J

    2007-05-01

    Understanding the signal transduction systems governing invasion is fundamental for the design of therapeutic strategies against metastasis. Na(+)/H(+) exchanger regulatory factor (NHERF1) is a postsynaptic density 95/disc-large/zona occludens (PDZ) domain-containing protein that recruits membrane receptors/transporters and cytoplasmic signaling proteins into functional complexes. NHERF1 expression is altered in breast cancer, but its effective role in mammary carcinogenesis remains undefined. We report here that NHERF1 overexpression in human breast tumor biopsies is associated with metastatic progression, poor prognosis, and hypoxia-inducible factor-1alpha expression. In cultured tumor cells, hypoxia and serum deprivation increase NHERF1 expression, promote the formation of leading-edge pseudopodia, and redistribute NHERF1 to these pseudopodia. This pseudopodial localization of NHERF1 was verified in breast biopsies and in three-dimensional Matrigel culture. Furthermore, serum deprivation and hypoxia stimulate the Na(+)/H(+) exchanger, invasion, and activate a protein kinase A (PKA)-gated RhoA/p38 invasion signal module. Significantly, NHERF1 overexpression was sufficient to induce these morphological and functional changes, and it potentiated their induction by serum deprivation. Functional experiments with truncated and binding groove-mutated PDZ domain constructs demonstrated that NHERF1 regulates these processes through its PDZ2 domain. We conclude that NHERF1 overexpression enhances the invasive phenotype in breast cancer cells, both alone and in synergy with exposure to the tumor microenvironment, via the coordination of PKA-gated RhoA/p38 signaling.

  5. Different conformational dynamics of PDZ1 and PDZ2 in full-length EBP50 analyzed by hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Park, Ji Young; Duc, Nguyen Minh; Kim, Dong Kyun; Lee, Su Youn; Li, Sheng; Seo, Min-Duk; Woods, Virgil L; Chung, Ka Young

    2015-08-01

    Ezrin-radixin-moesin-binding protein 50 (EBP50) is a scaffolding protein expressed in polarized epithelial cells in various organs, including the liver, kidney, and small intestine, in which it regulates the trafficking and targeting cellular proteins. EBP50 contains two postsynaptic density-95/disk-large/ZO-1 homology (PDZ) domains (e.g., PDZ1 and PDZ2) and an ezrin/radixin/moesin-binding (EB) domain. PDZ domains are one of the major scaffolding domains regulating protein-protein interactions with critical biological roles in cell polarity, migration, proliferation, recognition, and cell-cell interaction. PDZ1 and PDZ2 in EBP50 have different ligand selectivity, although several high-resolution structural studies of isolated PDZ1 and PDZ2 showed similar structures. We studied the conformations of full-length EBP50 and isolated PDZ1 and PDZ2 using hydrogen/deuterium exchange mass spectrometry (HDX-MS). The deuterium uptake profiles of isolated PDZ1 and PDZ2 were similar to those of full-length EBP50. Interestingly, PDZ1 was more dynamic than PDZ2, and these PDZ domains underwent different conformational changes upon ligand binding. These results might explain the differences in ligand-selectivity between PDZ1 and PDZ2.

  6. Investigating altered nitric oxide signalling as an up-stream mediator of the antidepressant action of ketamine

    DEFF Research Database (Denmark)

    Liebenberg, N.; Muller, H. K.; Elfving, B.

    2012-01-01

    in the FST 1 hour later, whereafter the frontal cortex regions were dissected for the measurement of nNOS activity and synaptic proteins (i.e. GluR1, GluR2, NR2A/B, NR1 and PSD-95) using western blotting. A vehicle-treated group of FRL rats was included as behavioural validation and to characterise the FSL...

  7. Inhibitory Interneurons That Express GFP in the PrP-GFP Mouse Spinal Cord Are Morphologically Heterogeneous, Innervated by Several Classes of Primary Afferent and Include Lamina I Projection Neurons among Their Postsynaptic Targets

    Science.gov (United States)

    Ganley, Robert P.; Iwagaki, Noboru; del Rio, Patricia; Baseer, Najma; Dickie, Allen C.; Boyle, Kieran A.; Polgár, Erika; Watanabe, Masahiko; Abraira, Victoria E; Zimmerman, Amanda

    2015-01-01

    The superficial dorsal horn of the spinal cord contains numerous inhibitory interneurons, which regulate the transmission of information perceived as touch, pain, or itch. Despite the importance of these cells, our understanding of their roles in the neuronal circuitry is limited by the difficulty in identifying functional populations. One group that has been identified and characterized consists of cells in the mouse that express green fluorescent protein (GFP) under control of the prion protein (PrP) promoter. Previous reports suggested that PrP-GFP cells belonged to a single morphological class (central cells), received inputs exclusively from unmyelinated primary afferents, and had axons that remained in lamina II. However, we recently reported that the PrP-GFP cells expressed neuronal nitric oxide synthase (nNOS) and/or galanin, and it has been shown that nNOS-expressing cells are more diverse in their morphology and synaptic connections. We therefore used a combined electrophysiological, pharmacological, and anatomical approach to reexamine the PrP-GFP cells. We provide evidence that they are morphologically diverse (corresponding to “unclassified” cells) and receive synaptic input from a variety of primary afferents, with convergence onto individual cells. We also show that their axons project into adjacent laminae and that they target putative projection neurons in lamina I. This indicates that the neuronal circuitry involving PrP-GFP cells is more complex than previously recognized, and suggests that they are likely to have several distinct roles in regulating the flow of somatosensory information through the dorsal horn. PMID:25972186

  8. Pyk2 modulates hippocampal excitatory synapses and contributes to cognitive deficits in a Huntington’s disease model

    KAUST Repository

    Giralt, Albert

    2017-05-30

    The structure and function of spines and excitatory synapses are under the dynamic control of multiple signalling networks. Although tyrosine phosphorylation is involved, its regulation and importance are not well understood. Here we study the role of Pyk2, a non-receptor calcium-dependent protein-tyrosine kinase highly expressed in the hippocampus. Hippocampal-related learning and CA1 long-term potentiation are severely impaired in Pyk2-deficient mice and are associated with alterations in NMDA receptors, PSD-95 and dendritic spines. In cultured hippocampal neurons, Pyk2 has autophosphorylation-dependent and -independent roles in determining PSD-95 enrichment and spines density. Pyk2 levels are decreased in the hippocampus of individuals with Huntington and in the R6/1 mouse model of the disease. Normalizing Pyk2 levels in the hippocampus of R6/1 mice rescues memory deficits, spines pathology and PSD-95 localization. Our results reveal a role for Pyk2 in spine structure and synaptic function, and suggest that its deficit contributes to Huntington’s disease cognitive impairments.

  9. Growth hormone promotes synaptogenesis and protects neuroretinal dendrites against kainic acid (KA) induced damage.

    Science.gov (United States)

    Fleming, Thomas; Martinez-Moreno, Carlos G; Carranza, Martha; Luna, Maricela; Harvey, Steve; Arámburo, Carlos

    2018-02-15

    There is increasing evidence that suggests a possible role for GH in retinal development and synaptogenesis. While our previous studies have focused largely on embryonic retinal ganglion cells (RGCs), our current study demonstrates that GH has a synaptogenic effect in retinal primary cell cultures, increasing the abundance of both pre- (SNAP25) and post- (PSD95) synaptic proteins. In the neonatal chick, kainate (KA) treatment was found to damage retinal synapses and abrogate GH expression. In response to damage, an increase in Cy3-GH internalization into RGCs was observed when administered shortly before or after damage. This increase in internalization also correlated with increase in PSD95 expression, suggesting a neuroprotective effect on the dendritic trees of RGCs and the inner plexiform layer (IPL). In addition, we observed the presence of PSD95 positive Müller glia, which may suggest GH is having a neuroregenerative effect in the kainate-damaged retina. This work puts forth further evidence that GH acts as a synaptogenic modulator in the chick retina and opens a new possibility for the use of GH in retinal regeneration research. Copyright © 2018. Published by Elsevier Inc.

  10. Synthesis and screening of support-bound combinatorial peptide libraries with free C-termini: determination of the sequence specificity of PDZ domains.

    Science.gov (United States)

    Joo, Sang Hoon; Pei, Dehua

    2008-03-04

    Preparation of support-bound combinatorial peptide libraries with free C-termini has been challenging in the past because solid-phase peptide synthesis usually starts from the C-terminus, which must be covalently attached to the solid support. In this work, we have developed a general methodology to synthesize and screen one-bead-one-compound peptide libraries containing free C-termini. TentaGel microbeads (90 mum) were spatially segregated into outer and inner layers, and peptides were synthesized on the beads in the conventional C --> N manner, with their C-termini attached to the support through an ester linkage on the bead surface but through an amide bond in the bead interior. The surface peptides were cyclized between their N-terminal amine and a carboxyl group installed at a C-terminal linker sequence, while the internal peptides were kept in the linear form. Base hydrolysis of the ester linkage in the cyclic peptides regenerated linear peptides that contained a free alpha-carboxyl group at their C-termini but remained covalently attached to the resin via the N-termini ("inverted" peptides). An inverted peptide library containing five random residues (theoretical diversity of 3.2 x 10 (6)) was synthesized and screened for binding to four postsynaptic density-95/discs large/zona occluden-1 (PDZ) domains of sodium-hydrogen exchanger regulatory factor-1 (NHERF1) and channel-interacting PDZ domain protein (CIPP). The identity of the binding peptides was determined by sequencing the linear encoding peptides inside the bead by partial Edman degradation/mass spectrometry. Consensus recognition motifs were identified for the PDZ domains, and representative peptides were resynthesized and confirmed for binding to their cognate PDZ domains. This method should be generally applicable to all PDZ domains as well as other protein domains and enzymes that recognize the C-terminus of their target proteins.

  11. Alterations in Brain Inflammation, Synaptic Proteins, and Adult Hippocampal Neurogenesis during Epileptogenesis in Mice Lacking Synapsin2

    Science.gov (United States)

    Chugh, Deepti; Ali, Idrish; Bakochi, Anahita; Bahonjic, Elma; Etholm, Lars; Ekdahl, Christine T.

    2015-01-01

    Synapsins are pre-synaptic vesicle-associated proteins linked to the pathogenesis of epilepsy through genetic association studies in humans. Deletion of synapsins causes an excitatory/inhibitory imbalance, exemplified by the epileptic phenotype of synapsin knockout mice. These mice develop handling-induced tonic-clonic seizures starting at the age of about 3 months. Hence, they provide an opportunity to study epileptogenic alterations in a temporally controlled manner. Here, we evaluated brain inflammation, synaptic protein expression, and adult hippocampal neurogenesis in the epileptogenic (1 and 2 months of age) and tonic-clonic (3.5-4 months) phase of synapsin 2 knockout mice using immunohistochemical and biochemical assays. In the epileptogenic phase, region-specific microglial activation was evident, accompanied by an increase in the chemokine receptor CX3CR1, interleukin-6, and tumor necrosis factor-α, and a decrease in chemokine keratinocyte chemoattractant/ growth-related oncogene. Both post-synaptic density-95 and gephyrin, scaffolding proteins at excitatory and inhibitory synapses, respectively, showed a significant up-regulation primarily in the cortex. Furthermore, we observed an increase in the inhibitory adhesion molecules neuroligin-2 and neurofascin and potassium chloride co-transporter KCC2. Decreased expression of γ-aminobutyric acid receptor-δ subunit and cholecystokinin was also evident. Surprisingly, hippocampal neurogenesis was reduced in the epileptogenic phase. Taken together, we report molecular alterations in brain inflammation and excitatory/inhibitory balance that could serve as potential targets for therapeutics and diagnostic biomarkers. In addition, the regional differences in brain inflammation and synaptic protein expression indicate an epileptogenic zone from where the generalized seizures in synapsin 2 knockout mice may be initiated or spread. PMID:26177381

  12. Alterations in Brain Inflammation, Synaptic Proteins, and Adult Hippocampal Neurogenesis during Epileptogenesis in Mice Lacking Synapsin2.

    Directory of Open Access Journals (Sweden)

    Deepti Chugh

    Full Text Available Synapsins are pre-synaptic vesicle-associated proteins linked to the pathogenesis of epilepsy through genetic association studies in humans. Deletion of synapsins causes an excitatory/inhibitory imbalance, exemplified by the epileptic phenotype of synapsin knockout mice. These mice develop handling-induced tonic-clonic seizures starting at the age of about 3 months. Hence, they provide an opportunity to study epileptogenic alterations in a temporally controlled manner. Here, we evaluated brain inflammation, synaptic protein expression, and adult hippocampal neurogenesis in the epileptogenic (1 and 2 months of age and tonic-clonic (3.5-4 months phase of synapsin 2 knockout mice using immunohistochemical and biochemical assays. In the epileptogenic phase, region-specific microglial activation was evident, accompanied by an increase in the chemokine receptor CX3CR1, interleukin-6, and tumor necrosis factor-α, and a decrease in chemokine keratinocyte chemoattractant/ growth-related oncogene. Both post-synaptic density-95 and gephyrin, scaffolding proteins at excitatory and inhibitory synapses, respectively, showed a significant up-regulation primarily in the cortex. Furthermore, we observed an increase in the inhibitory adhesion molecules neuroligin-2 and neurofascin and potassium chloride co-transporter KCC2. Decreased expression of γ-aminobutyric acid receptor-δ subunit and cholecystokinin was also evident. Surprisingly, hippocampal neurogenesis was reduced in the epileptogenic phase. Taken together, we report molecular alterations in brain inflammation and excitatory/inhibitory balance that could serve as potential targets for therapeutics and diagnostic biomarkers. In addition, the regional differences in brain inflammation and synaptic protein expression indicate an epileptogenic zone from where the generalized seizures in synapsin 2 knockout mice may be initiated or spread.

  13. Milnacipran remediates impulsive deficits in rats with lesions of the ventromedial prefrontal cortex.

    Science.gov (United States)

    Tsutsui-Kimura, Iku; Yoshida, Takayuki; Ohmura, Yu; Izumi, Takeshi; Yoshioka, Mitsuhiro

    2014-12-08

    Deficits in impulse control are often observed in psychiatric disorders in which abnormalities of the prefrontal cortex are observed, including attention-deficit/hyperactivity disorder and bipolar disorder. We recently found that milnacipran, a serotonin/noradrenaline reuptake inhibitor, could suppress impulsive action in normal rats. However, whether milnacipran could suppress elevated impulsive action in rats with lesions of the ventromedial prefrontal cortex, which is functionally comparable with the human prefrontal cortex, remains unknown. Selective lesions of the ventromedial prefrontal cortex were made using quinolinic acid in rats previously trained on a 3-choice serial reaction time task. Sham rats received phosphate buffered saline. Following a period of recovery, milnacipran (0 or 10mg/kg/d × 14 days) was orally administered 60 minutes prior to testing on the 3-choice task. After 7 days of drug cessation, Western blotting, immunohistochemistry, electrophysiological analysis, and morphological analysis were conducted. Lesions of the ventromedial prefrontal cortex induced impulsive deficits, and repeated milnacipran ameliorated the impulsive deficit both during the dosing period and after the cessation of the drug. Repeated milnacipran remediated the protein levels of mature brain-derived neurotrophic factor and postsynaptic density-95, dendritic spine density, and excitatory currents in the few surviving neurons in the ventromedial prefrontal cortex of ventromedial prefrontal cortex-lesioned rats. The findings of this study suggest that milnacipran treatment could be a novel strategy for the treatment of psychiatric disorders that are associated with a lack of impulse control. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  14. Awake intranasal insulin delivery modifies protein complexes and alters memory, anxiety, and olfactory behaviors.

    Science.gov (United States)

    Marks, David R; Tucker, Kristal; Cavallin, Melissa A; Mast, Thomas G; Fadool, Debra A

    2009-05-20

    The role of insulin pathways in olfaction is of significant interest with the widespread pathology of diabetes mellitus and its associated metabolic and neuronal comorbidities. The insulin receptor (IR) kinase is expressed at high levels in the olfactory bulb, in which it suppresses a dominant Shaker ion channel (Kv1.3) via tyrosine phosphorylation of critical N- and C-terminal residues. We optimized a 7 d intranasal insulin delivery (IND) in awake mice to ascertain the biochemical and behavioral effects of insulin to this brain region, given that nasal sprays for insulin have been marketed notwithstanding our knowledge of the role of Kv1.3 in olfaction, metabolism, and axon targeting. IND evoked robust phosphorylation of Kv1.3, as well as increased channel protein-protein interactions with IR and postsynaptic density 95. IND-treated mice had an increased short- and long-term object memory recognition, increased anxiolytic behavior, and an increased odor discrimination using an odor habituation protocol but only moderate change in odor threshold using a two-choice paradigm. Unlike Kv1.3 gene-targeted deletion that alters metabolism, adiposity, and axonal targeting to defined olfactory glomeruli, suppression of Kv1.3 via IND had no effect on body weight nor the size and number of M72 glomeruli or the route of its sensory axon projections. There was no evidence of altered expression of sensory neurons in the epithelium. In mice made prediabetic via diet-induced obesity, IND was no longer effective in increasing long-term object memory recognition nor increasing anxiolytic behavior, suggesting state dependency or a degree of insulin resistance related to these behaviors.

  15. Awake Intranasal Insulin Delivery Modifies Protein Complexes and Alters Memory, Anxiety, and Olfactory Behaviors

    Science.gov (United States)

    Marks, D.R.; Tucker, K.; Cavallin, M.A.; Mast, T.G.; Fadool, D.A.

    2009-01-01

    The role of insulin pathways in olfaction is of significant interest with the widespread pathology of Diabetes mellitus and its associated metabolic and neuronal co-morbidities. The insulin receptor kinase (IR) is expressed at high levels in the olfactory bulb (OB), where it suppresses a dominant Shaker ion channel (Kv1.3) via tyrosine phosphorylation of critical N- and C-terminal residues. We optimized a seven day intranasal insulin delivery (IND) in awake mice to ascertain the biochemical and behavioral effects of insulin to this brain region, given that nasal sprays for insulin have been marketed notwithstanding our knowledge of the role of Kv1.3 in olfaction, metabolism, and axon targeting. IND evoked robust phosphorylation of Kv1.3, as well as increased channel protein-protein interactions with IR and post-synaptic density 95. IND-treated mice had an increased short- and long-term object memory recognition, increased anxiolytic behavior, and an increased odor-discrimination using an odor habituation protocol but only moderate change in odor threshold using a two-choice paradigm. Unlike Kv1.3 gene-targeted deletion that alters metabolism, adiposity, and axonal targeting to defined olfactory glomeruli, suppression of Kv1.3 via IND had no effect on body weight nor the size and number of M72 glomeruli or the route of its sensory axon projections. There was no evidence of altered expression of sensory neurons in the epithelium. In mice made pre-diabetic via diet-induced obesity, IND was no longer effective in increasing long-term object memory recognition nor increasing anxiolytic behavior, suggesting state dependency or a degree of insulin resistance related to these behaviors. PMID:19458242

  16. Differential palmitoylation directs the AMPA receptor-binding protein ABP to spines or to intracellular clusters.

    Science.gov (United States)

    DeSouza, Sunita; Fu, Jie; States, Bradley A; Ziff, Edward B

    2002-05-01

    Long-term changes in excitatory synapse strength are thought to reflect changes in synaptic abundance of AMPA receptors mediated by receptor trafficking. AMPA receptor-binding protein (ABP) and glutamate receptor-interacting protein (GRIP) are two similar PDZ (postsynaptic density 95/Discs large/zona occludens 1) proteins that interact with glutamate receptors 2 and 3 (GluR2 and GluR3) subunits. Both proteins have proposed roles during long-term potentiation and long-term depression in the delivery and anchorage of AMPA receptors at synapses. Here we report a variant of ABP-L (seven PDZ form of ABP) called pABP-L that is palmitoylated at a cysteine residue at position 11 within a novel 18 amino acid N-terminal leader sequence encoded through differential splicing. In cultured hippocampal neurons, nonpalmitoylated ABP-L localizes with internal GluR2 pools expressed from a Sindbis virus vector, whereas pABP-L is membrane targeted and associates with surface-localized GluR2 receptors at the plasma membrane in spines. Mutation of Cys-11 to alanine blocks the palmitoylation of pABP-L and targets the protein to intracellular clusters, confirming that targeting the protein to spines is dependent on palmitoylation. Non-palmitoylated GRIP is primarily intracellular, but a chimera with the pABP-L N-terminal palmitoylation sequence linked to the body of the GRIP protein is targeted to spines. We suggest that pABP-L and ABP-L provide, respectively, synaptic and intracellular sites for the anchorage of AMPA receptors during receptor trafficking to and from the synapse.

  17. Preventive Effects of Resveratrol on Endocannabinoid System and Synaptic Protein Modifications in Rat Cerebral Cortex Challenged by Bilateral Common Carotid Artery Occlusion and Reperfusion

    Directory of Open Access Journals (Sweden)

    Gianfranca Carta

    2018-01-01

    Full Text Available This study aims to evaluate the putative roles of a single acute dose of resveratrol (RVT in preventing cerebral oxidative stress induced by bilateral common carotid artery occlusion, followed by reperfusion (BCCAO/R and to investigate RVT’s ability to preserve the neuronal structural integrity. Frontal and temporal-occipital cortices were examined in two groups of adult Wistar rats, sham-operated and submitted to BCCAO/R. In both groups, 6 h before surgery, half the rats were gavage-fed with a single dose of RVT (40 mg/per rat in 300 µL of sunflower oil as the vehicle, while the second half received the vehicle alone. In the frontal cortex, RVT pre-treatment prevented the BCCAO/R-induced increase of lipoperoxides, augmented concentrations of palmitoylethanolamide and docosahexaenoic acid, increased relative levels of the cannabinoid receptors type 1 (CB1 and 2 (CB2, and peroxisome-proliferator-activated-receptor (PPAR-α proteins. Increased expression of CB1/CB2 receptors mirrored that of synaptophysin and post-synaptic density-95 protein. No BCCAO/R-induced changes occurred in the temporal-occipital cortex. Collectively, our results demonstrate that, in the frontal cortex, RVT pre-treatment prevents the BCCAO/R-induced oxidative stress and modulates the endocannabinoid and PPAR-α systems. The increased expression of synaptic structural proteins further suggests the possible efficacy of RVT as a dietary supplement to preserve the nervous tissue metabolism and control the physiological response to the hypoperfusion/reperfusion challenge.

  18. Abnormal activity of the MAPK- and cAMP-associated signaling pathways in frontal cortical areas in postmortem brain in schizophrenia.

    Science.gov (United States)

    Funk, Adam J; McCullumsmith, Robert E; Haroutunian, Vahram; Meador-Woodruff, James H

    2012-03-01

    Recent evidence suggests that schizophrenia may result from alterations of integration of signaling mediated by multiple neurotransmitter systems. Abnormalities of associated intracellular signaling pathways may contribute to the pathophysiology of schizophrenia. Proteins and phospho-proteins comprising mitogen activated protein kinase (MAPK) and 3'-5'-cyclic adenosine monophosphate (cAMP)-associated signaling pathways may be abnormally expressed in the anterior cingulate (ACC) and dorsolateral prefrontal cortex (DLPFC) in schizophrenia. Using western blot analysis we examined proteins of the MAPK- and cAMP-associated pathways in these two brain regions. Postmortem samples were used from a well-characterized collection of elderly patients with schizophrenia (ACC=36, DLPFC=35) and a comparison (ACC=33, DLPFC=31) group. Near-infrared intensity of IR-dye labeled secondary antisera bound to targeted proteins of the MAPK- and cAMP-associated signaling pathways was measured using LiCor Odyssey imaging system. We found decreased expression of Rap2, JNK1, JNK2, PSD-95, and decreased phosphorylation of JNK1/2 at T183/Y185 and PSD-95 at S295 in the ACC in schizophrenia. In the DLPFC, we found increased expression of Rack1, Fyn, Cdk5, and increased phosphorylation of PSD-95 at S295 and NR2B at Y1336. MAPK- and cAMP-associated molecules constitute ubiquitous intracellular signaling pathways that integrate extracellular stimuli, modify receptor expression and function, and regulate cell survival and neuroplasticity. These data suggest abnormal activity of the MAPK- and cAMP-associated pathways in frontal cortical areas in schizophrenia. These alterations may underlie the hypothesized hypoglutamatergic function in this illness. Together with previous findings, these data suggest that abnormalities of intracellular signaling pathways may contribute to the pathophysiology of schizophrenia.

  19. Sensitivity to isoflurane anesthesia increases in autism spectrum disorder Shank3+/∆c mutant mouse model.

    Science.gov (United States)

    Li, Changsheng; Schaefer, Michele; Gray, Christy; Yang, Ya; Furmanski, Orion; Liu, Sufang; Worley, Paul; Mintz, C David; Tao, Feng; Johns, Roger A

    Autism is a heterogeneous developmental disorder characterized by impaired social interaction, impaired communication skills, and restricted and repetitive behavior. The abnormal behaviors of these patients can make their anesthetic and perioperative management difficult. Evidence in the literature suggests that some patients with autism or specific autism spectrum disorders (ASD) exhibit altered responses to pain and to anesthesia or sedation. A genetic mouse model of one particular ASD, Phelan McDermid Syndrome, has been developed that has a Shank3 haplotype truncation (Shank3+/Δc). These mice exhibit important characteristics of autism that mimic human autistic behavior. Our study demonstrates that a Shank3+/ΔC mutation in mice is associated with a reduction in both the MAC and RREC50 of isoflurane and down regulation of NR1 in vestibular nuclei and PSD95 in spinal cord. Decreased expression of NR1 and PSD95 in the central nervous system of Shank3+/ΔC mice could help reduce the MAC and RREC50 of isoflurane, which would warrant confirmation in a clinical study. If Shank3 mutations are found to affect anesthetic sensitivity in patients with ASD, better communication and stricter monitoring of anesthetic depth may be necessary. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Prenatal music stimulation facilitates the postnatal functional development of the auditory as well as visual system in chicks (Gallus domesticus).

    Science.gov (United States)

    Roy, Saborni; Nag, Tapas C; Upadhyay, Ashish Datt; Mathur, Rashmi; Jain, Suman

    2014-03-01

    Rhythmic sound or music is known to improve cognition in animals and humans. We wanted to evaluate the effects of prenatal repetitive music stimulation on the remodelling of the auditory cortex and visual Wulst in chicks. Fertilized eggs (0 day) of white leghorn chicken (Gallus domesticus) during incubation were exposed either to music or no sound from embryonic day 10 until hatching. Auditory and visual perceptual learning and synaptic plasticity, as evident by synaptophysin and PSD-95 expression, were done at posthatch days (PH) 1, 2 and 3. The number of responders was significantly higher in the music stimulated group as compared to controls at PH1 in both auditory and visual preference tests. The stimulated chicks took significantly lesser time to enter and spent more time in the maternal area in both preference tests. A significantly higher expression of synaptophysin and PSD-95 was observed in the stimulated group in comparison to control at PH1-3 both in the auditory cortex and visual Wulst. A significant inter-hemispheric and gender-based difference in expression was also found in all groups. These results suggest facilitation of postnatal perceptual behaviour and synaptic plasticity in both auditory and visual systems following prenatal stimulation with complex rhythmic music.

  1. [Effect of diallyl disulfide on learning and memory abilities and hippocampal synapses in mouse models of Alzheimer's disease].

    Science.gov (United States)

    Chai, Ji-Xia; Li, Hui-Hui; Wang, Yuan-Yuan; Chai, Qiang; He, Wen-Xin; Zhou, Yan-Mei; Hu, Xiao-Dong; Wang, Zhen-Huan

    2016-10-20

    To explore the effect of diallyl disulfide (DADS) on hippocampal synapses and learning and memory abilities in a mouse model of A1zheimer's disease (AD). Mouse models of AD established by agglutinated Aβ1-42 injection in the lateral cerebral ventricle were randomized into 4 groups and treated with DADS at the daily doses of 0, 10, 50 and 100 mg/kg by gavage for 30 consecutive days. The learning and memory abilities of the mice were assessed with Morris water maze test; the structures of the dendritic spines and synapses in CA1 region of the hippocampus were observed under transmission electron microscope with silver staining; PSD95 and SYP protein and mRNA expressions in the hippocampus were detected with Western blotting and RT-PCR. Compared with the AD model mice, the mice treated with 50 and 100 mg/kg DADS showed enhanced learning and memory abilities in Morris water maze test. The dendritic spines and synapses in CA1 region of the hippocampus increased obviously and hippocampal expressions of PSD95 and SYP were enhanced in mice treated with 50 and 100 mg/kg DADS. DADS at the daily doses of 50 and 100 mg/kg can improve the learning and memory abilities and increase the number of dendritic spines and synapses in the hippocampus in mouse models of AD.

  2. Different effects of bisphenol-A on memory behavior and synaptic modification in intact and estrogen-deprived female mice.

    Science.gov (United States)

    Xu, Xiaohong; Gu, Ting; Shen, Qiaoqiao

    2015-03-01

    Bisphenol-A (BPA) has the capability of interfering with the effects of estrogens on modulating brain function. The purpose of this study was to investigate the effects of BPA on memory and synaptic modification in the hippocampus of female mice under different levels of cycling estrogen. BPA exposure (40, 400 μg/kg/day) for 8 weeks did not affect spatial memory and passive avoidance task of gonadally intact mice but improved ovariectomy (Ovx)-induced memory impairment, whereas co-exposure of BPA with estradiol benzoate (EB) diminished the rescue effect of EB on memory behavior of Ovx mice. The results of morphometric measurement showed that BPA positively modified the synaptic interface structure and increased the synaptic density of CA1 pyramidal cell in the hippocampus of Ovx females, but inhibited the enhancement of EB on synaptic modification and synaptogenesis of Ovx mice. Furthermore, BPA up-regulated synaptic proteins synapsin I and PSD-95 and NMDA receptor NR2B but inhibited EB-induced increase in PSD-95 and NR2B in the hippocampus of Ovx mice. These results suggest that BPA interfered with normal hormonal regulation in synaptic plasticity and memory of female mice as a potent estrogen mimetic and as a disruptor of estrogen under various concentrations of cycling estrogen. © 2014 International Society for Neurochemistry.

  3. Proteomic Characterization of a Mouse Model of Familial Danish Dementia

    Directory of Open Access Journals (Sweden)

    Monica Vitale

    2012-01-01

    Full Text Available A dominant mutation in the ITM2B/BRI2 gene causes familial Danish dementia (FDD in humans. To model FDD in animal systems, a knock-in approach was recently implemented in mice expressing a wild-type and mutant allele, which bears the FDD-associated mutation. Since these FDDKI mice show behavioural alterations and impaired synaptic function, we characterized their synaptosomal proteome via two-dimensional differential in-gel electrophoresis. After identification by nanoliquid chromatography coupled to electrospray-linear ion trap tandem mass spectrometry, the differentially expressed proteins were classified according to their gene ontology descriptions and their predicted functional interactions. The Dlg4/Psd95 scaffold protein and additional signalling proteins, including protein phosphatases, were revealed by STRING analysis as potential players in the altered synaptic function of FDDKI mice. Immunoblotting analysis finally demonstrated the actual downregulation of the synaptosomal scaffold protein Dlg4/Psd95 and of the dual-specificity phosphatase Dusp3 in the synaptosomes of FDDKI mice.

  4. NeuroD2 regulates the development of hippocampal mossy fiber synapses

    Directory of Open Access Journals (Sweden)

    Wilke Scott A

    2012-02-01

    Full Text Available Abstract Background The assembly of neural circuits requires the concerted action of both genetically determined and activity-dependent mechanisms. Calcium-regulated transcription may link these processes, but the influence of specific transcription factors on the differentiation of synapse-specific properties is poorly understood. Here we characterize the influence of NeuroD2, a calcium-dependent transcription factor, in regulating the structural and functional maturation of the hippocampal mossy fiber (MF synapse. Results Using NeuroD2 null mice and in vivo lentivirus-mediated gene knockdown, we demonstrate a critical role for NeuroD2 in the formation of CA3 dendritic spines receiving MF inputs. We also use electrophysiological recordings from CA3 neurons while stimulating MF axons to show that NeuroD2 regulates the differentiation of functional properties at the MF synapse. Finally, we find that NeuroD2 regulates PSD95 expression in hippocampal neurons and that PSD95 loss of function in vivo reproduces CA3 neuron spine defects observed in NeuroD2 null mice. Conclusion These experiments identify NeuroD2 as a key transcription factor that regulates the structural and functional differentiation of MF synapses in vivo.

  5. Disruption of neuronal nitric oxide synthase dimerization contributes to the development of Alzheimer's disease: Involvement of cyclin-dependent kinase 5-mediated phosphorylation of neuronal nitric oxide synthase at Ser(293).

    Science.gov (United States)

    Kwon, Kyoung Ja; Park, Jung-Hyun; Jo, Inho; Song, Kee-Ho; Han, Jung-Soo; Park, Seung Hwa; Han, Seol-Heui; Cho, Du-Hyong

    2016-10-01

    Although previous studies have suggested that neuronal nitric oxide synthase (nNOS)-derived NO has neuroprotective effects on the development of Alzheimer's disease (AD), the underlying molecular mechanisms are not fully elucidated. Here, we investigated whether and how disruption of nNOS dimerization contributes to the development of AD. No differences in synaptic number or expression of synaptic markers, including synaptophysin and postsynaptic density 95, were found in the cortex of 5 × FAD mice, which possess 5 familial AD mutations, at 6 months of age compared with control littermates. nNOS dimerization was disrupted in the 5 × FAD cortex, accompanied by an increase in reactive oxygen species (ROS) production. The subcellular distribution of cyclin-dependent kinase 5 (CDK5) shifted more diffusely toward a cytosolic compartment, but there was no change in total expression. Furthermore, the levels of p25, a CDK5 activator, increased significantly and it colocalized with nNOS in the 5 × FAD cortex. In silico analysis revealed that a new nNOS-specific GSP (glycine-serine-proline) motif was well-conserved across species at nNOS-Ser(293), which is located ahead of the N-terminal hook. This motif was not present in the closely related isoform, endothelial NOS. Motif scan analysis also predicted that CDK5 can phosphorylate nNOS-Ser(293) with a high likelihood. An in vitro phosphorylation assay clearly showed that CDK5/p25 does indeed phosphorylate nNOS-Ser(293). Finally, nNOS-S293D mutant, a phosphomimetic form of nNOS-Ser(293), and nNOS-S293A mutant, a neutral form of nNOS-Ser(293), significantly decreased nNOS dimerization and NO production. Taken together, our results demonstrate that nNOS dimers are disrupted in the 5 × FAD cortex, and nNOS-Ser(293), a potential site of CDK5 phosphorylation, may be involved in the decrease in nNOS dimerization and NO production, and the development of AD. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Alterations in STriatal-Enriched protein tyrosine Phosphatase expression, activation, and downstream signaling in early and late stages of the YAC128 Huntington's disease mouse model.

    Science.gov (United States)

    Gladding, Clare M; Fan, Jing; Zhang, Lily Y J; Wang, Liang; Xu, Jian; Li, Edward H Y; Lombroso, Paul J; Raymond, Lynn A

    2014-07-01

    Striatal neurodegeneration and synaptic dysfunction in Huntington's disease are mediated by the mutant huntingtin (mHtt) protein. MHtt disrupts calcium homeostasis and facilitates excitotoxicity, in part by altering NMDA receptor (NMDAR) trafficking and function. Pre-symptomatic (excitotoxin-sensitive) transgenic mice expressing full-length human mHtt with 128 polyglutamine repeats (YAC128 Huntington's disease mice) show increased calpain activity and extrasynaptic NMDAR (Ex-NMDAR) localization and signaling. Furthermore, Ex-NMDAR stimulation facilitates excitotoxicity in wild-type cortical neurons via calpain-mediated cleavage of STriatal-Enriched protein tyrosine Phosphatase 61 (STEP61). The cleavage product, STEP33, cannot dephosphorylate p38 mitogen-activated protein kinase (MAPK), thereby augmenting apoptotic signaling. Here, we show elevated extrasynaptic calpain-mediated cleavage of STEP61 and p38 phosphorylation, as well as STEP61 inactivation and reduced extracellular signal-regulated protein kinase 1/2 phosphorylation (ERK1/2) in the striatum of 6-week-old, excitotoxin-sensitive YAC128 mice. Calpain inhibition reduced basal and NMDA-induced STEP61 cleavage. However, basal p38 phosphorylation was normalized by a peptide disrupting NMDAR-post-synaptic density protein-95 (PSD-95) binding but not by calpain inhibition. In 1-year-old excitotoxin-resistant YAC128 mice, STEP33 levels were not elevated, but STEP61 inactivation and p38 and ERK 1/2 phosphorylation levels were increased. These results show that in YAC128 striatal tissue, enhanced NMDAR-PSD-95 interactions contributes to elevated p38 signaling in early, excitotoxin-sensitive stages, and suggest that STEP61 inactivation enhances MAPK signaling at late, excitotoxin-resistant stages. The YAC128 Huntington's disease mouse model shows early, enhanced susceptibility to NMDA receptor-mediated striatal apoptosis, progressing to late-stage excitotoxicity resistance. This study shows that elevated NMDA

  7. Endogenous opioids regulate moment-to-moment neuronal communication and excitability

    National Research Council Canada - National Science Library

    Bryony L Winters; Gabrielle C Gregoriou; Sarah A Kissiwaa; Oliver A Wells; Danashi I Medagoda; Sam M Hermes; Neil T Burford; Andrew Alt; Sue A Aicher; Elena E Bagley

    2017-01-01

    .... Postsynaptically, the opioids activate a potassium conductance through the μ-opioid receptor (MOR), suggesting for the first time that endogenously released opioids directly regulate neuronal excitability...

  8. The role of ubiquitin‐mediated pathways in regulating synaptic development, axonal degeneration and regeneration: insights from fly and worm

    National Research Council Canada - National Science Library

    Tian, Xiaolin; Wu, Chunlai

    2013-01-01

    ...‐mediated pathways play important roles in controlling the presynaptic size, synaptic elimination and stabilization, synaptic transmission, postsynaptic receptor abundance, axonal degeneration and regeneration...

  9. Minireview: Role of Intracellular Scaffolding Proteins in the Regulation of Endocrine G Protein-Coupled Receptor Signaling

    Science.gov (United States)

    Walther, Cornelia

    2015-01-01

    The majority of hormones stimulates and mediates their signal transduction via G protein-coupled receptors (GPCRs). The signal is transmitted into the cell due to the association of the GPCRs with heterotrimeric G proteins, which in turn activates an extensive array of signaling pathways to regulate cell physiology. However, GPCRs also function as scaffolds for the recruitment of a variety of cytoplasmic protein-interacting proteins that bind to both the intracellular face and protein interaction motifs encoded by GPCRs. The structural scaffolding of these proteins allows GPCRs to recruit large functional complexes that serve to modulate both G protein-dependent and -independent cellular signaling pathways and modulate GPCR intracellular trafficking. This review focuses on GPCR interacting PSD95-disc large-zona occludens domain containing scaffolds in the regulation of endocrine receptor signaling as well as their potential role as therapeutic targets for the treatment of endocrinopathies. PMID:25942107

  10. Oridonin Attenuates Synaptic Loss and Cognitive Deficits in an Aβ1-42-Induced Mouse Model of Alzheimer's Disease.

    Directory of Open Access Journals (Sweden)

    Sulei Wang

    Full Text Available Synaptic loss induced by beta-amyloid (Aβ plays a critical role in the pathophysiology of Alzheimer's disease (AD, but the mechanisms underlying this process remain unknown. In this study, we found that oridonin (Ori rescued synaptic loss induced by Aβ1-42 in vivo and in vitro and attenuated the alterations in dendritic structure and spine density observed in the hippocampus of AD mice. In addition, Ori increased the expression of PSD-95 and synaptophysin and promoted mitochondrial activity in the synaptosomes of AD mice. Ori also activated the BDNF/TrkB/CREB signaling pathway in the hippocampus of AD mice. Furthermore, in the Morris water maze test, Ori reduced latency and searching distance and increased the number of platform crosses in AD mice. These data suggest that Ori might prevent synaptic loss and improve behavioral symptoms in Aβ1-42-induced AD mice.

  11. Targeting Protein-Protein Interactions with Trimeric Ligands: High Affinity Inhibitors of the MAGUK Protein Family

    DEFF Research Database (Denmark)

    Nissen, Klaus B; Kedström, Linda Maria Haugaard; Wilbek, Theis S

    2015-01-01

    and the related MAGUK proteins contain three consecutive PDZ domains, hence we envisioned that targeting all three PDZ domains simultaneously would lead to more potent and potentially more specific interactions with the MAGUK proteins. Here we describe the design, synthesis and characterization of a series...... of trimeric ligands targeting all three PDZ domains of PSD-95 and the related MAGUK proteins, PSD-93, SAP-97 and SAP-102. Using our dimeric ligands targeting the PDZ1-2 tandem as starting point, we designed novel trimeric ligands by introducing a PDZ3-binding peptide moiety via a cysteine-derivatized NPEG...... linker. The trimeric ligands generally displayed increased affinities compared to the dimeric ligands in fluorescence polarization binding experiments and optimized trimeric ligands showed low nanomolar inhibition towards the four MAGUK proteins, thus being the most potent inhibitors described. Kinetic...

  12. Comparison of phase dyssynchrony analysis using gated myocardial perfusion imaging with four software programs: Based on the Japanese Society of Nuclear Medicine working group normal database.

    Science.gov (United States)

    Nakajima, Kenichi; Okuda, Koichi; Matsuo, Shinro; Kiso, Keisuke; Kinuya, Seigo; Garcia, Ernest V

    2017-04-01

    Left ventricular (LV) phase dyssynchrony parameters based on gated myocardial perfusion imaging varied among software programs. The aim of this study was to determine normal ranges and factors affecting phase parameters. Normal databases were derived from the Japanese Society of Nuclear Medicine working group (n = 69). The programs were Emory Cardiac Toolbox with SyncTool (ECTb), Quantitative Gated SPECT (QGS), Heart Function View (HFV), and cardioREPO (cREPO); parameters of phase standard deviation (PSD), 95% bandwidth, and entropy were compared with parameters with ECTb as a reference. PSD (degree) was 5.3 ± 3.3 for QGS (P software types. Based on normal ranges of phase dyssynchrony parameters in four software programs, dependency on genders, LV volume, and EF should be considered, indicating the need for careful comparison among different software programs.

  13. Dendrite extension by methanol extract of Ashwagandha (roots of Withania somnifera) in SK-N-SH cells.

    Science.gov (United States)

    Tohda, C; Kuboyama, T; Komatsu, K

    2000-06-26

    Extension of dendrites and axons in neurons may compensate for and repair damaged neuronal circuits in the dementia brain. Our aim in the present study was to explore drugs activating neurite outgrowth and regenerating the neuronal network. We found that the methanol extract of Ashwagandha (roots of Withania somnifera; 5 microg/ml) significantly increased the percentage of cells with neurites in human neuroblastoma SK-N-SH cells. The effect of the extract was dose- and time-dependent mRNA levels of the dendritic markers MAP2 and PSD-95 by RT-PCR were found to be markedly increased by treatment with the extract, whereas those of the axonal marker Tau were not. Immunocytochemistry demonstrated the specific expression of MAP2 in neurites extended by the extract. These results suggest that the methanol extract of Ashwagandha promotes the formation of dendrites.

  14. Splicing-Dependent Trans-synaptic SALM3–LAR-RPTP Interactions Regulate Excitatory Synapse Development and Locomotion

    Directory of Open Access Journals (Sweden)

    Yan Li

    2015-09-01

    Full Text Available Synaptic adhesion molecules regulate diverse aspects of synapse development and plasticity. SALM3 is a PSD-95-interacting synaptic adhesion molecule known to induce presynaptic differentiation in contacting axons, but little is known about its presynaptic receptors and in vivo functions. Here, we identify an interaction between SALM3 and LAR family receptor protein tyrosine phosphatases (LAR-RPTPs that requires the mini-exon B splice insert in LAR-RPTPs. In addition, SALM3-dependent presynaptic differentiation requires all three types of LAR-RPTPs. SALM3 mutant (Salm3−/− mice display markedly reduced excitatory synapse number but normal synaptic plasticity in the hippocampal CA1 region. Salm3−/− mice exhibit hypoactivity in both novel and familiar environments but perform normally in learning and memory tests administered. These results suggest that SALM3 regulates excitatory synapse development and locomotion behavior.

  15. Molecular handoffs in nitrergic neurotransmission

    Directory of Open Access Journals (Sweden)

    ARUN eCHAUDHURY

    2014-04-01

    Full Text Available PSD proteins in excitatory synapses are relatively immobile components, while there is a structured organization of mobile scaffolding proteins lying beneath the PSDs. For example, shank proteins are located further away from the membrane in the cytosolic faces of the PSDs, facing the actin cytoskeleton. The rationale of this organization may be related to important roles of these proteins as exchange hubs for the signaling proteins for their migration from the subcortical cytosol to the membrane. Notably, PSD95 have also been demonstrated in prejunctional nerve terminals of nitrergic neuronal varicosities traversing the gastrointestinal smooth muscles. It has been recently reported that motor proteins like myosin Va play important role in transcytosis of nNOS. In this review, the hypothesis is forwarded that nNOS delivered to subcortical cytoskeleton requires interactions with scaffolding proteins prior to docking at the membrane. This may involve suggest significant role of shank, named for SRC homology (SH3 and multiple ankyrin repeat domains, in nitric oxide synthesis. Dynein light chain LC8-nNOS from acto-myosin Va is possibly exchanged with shank, which thereafter facilitates transposition of nNOS for binding with palmitoyl-PSD95 at the nerve terminal membrane. Shank knockout mice, which present with features of autism spectrum disorders, may help delineate the role of shank in enteric nitrergic neuromuscular transmission. Deletion of shank3 in humans is a monogenic cause of autism called Phelan-McDermid syndrome. One fourth of these patients present with cyclical vomiting, which may be explained by junctionopathy resulting from shank deficit in enteric nitrergic nerve terminals.

  16. High speed two-photon imaging of calcium dynamics in dendritic spines: consequences for spine calcium kinetics and buffer capacity

    NARCIS (Netherlands)

    Cornelisse, L.N.; van Elburg, R.A.J.; Meredith, R.M.; Yuste, R.; Mansvelder, H.D.

    2007-01-01

    Rapid calcium concentration changes in postsynaptic structures are crucial for synaptic plasticity. Thus far, the determinants of postsynaptic calcium dynamics have been studied predominantly based on the decay kinetics of calcium transients. Calcium rise times in spines in response to single action

  17. High Speed Two-Photon Imaging of Calcium Dynamics in Dendritic Spines: : Consequences for Spine Calcium Kinetics and Buffer Capacity

    NARCIS (Netherlands)

    van Elburg, R.A.J.; Cornelisse, L.N; Meredith, R.M; Yuste, R; Mansvelder, H.D

    2007-01-01

    Rapid calcium concentration changes in postsynaptic structures are crucial for synaptic plasticity. Thus far, the determinants of postsynaptic calcium dynamics have been studied predominantly based on the decay kinetics of calcium transients. Calcium rise times in spines in response to single action

  18. …with Love, from Post to Pre.

    Science.gov (United States)

    Poirazi, Panayiota; Kastellakis, George

    2017-09-27

    In this issue of Neuron, Costa et al. (2017) introduce a theoretical framework that predicts the ratio of presynaptic and postsynaptic changes taking place during LTP and LTD and show that these processes co-operate so as to optimize the postsynaptic response statistics. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Self-assembly and plasticity of synaptic domains through a reaction-diffusion mechanism

    Science.gov (United States)

    Haselwandter, Christoph A.; Kardar, Mehran; Triller, Antoine; da Silveira, Rava Azeredo

    2015-09-01

    Signal transmission across chemical synapses relies crucially on neurotransmitter receptor molecules, concentrated in postsynaptic membrane domains along with scaffold and other postsynaptic molecules. The strength of the transmitted signal depends on the number of receptor molecules in postsynaptic domains, and activity-induced variation in the receptor number is one of the mechanisms of postsynaptic plasticity. Recent experiments have demonstrated that the reaction and diffusion properties of receptors and scaffolds at the membrane, alone, yield spontaneous formation of receptor-scaffold domains of the stable characteristic size observed in neurons. On the basis of these experiments we develop a model describing synaptic receptor domains in terms of the underlying reaction-diffusion processes. Our model predicts that the spontaneous formation of receptor-scaffold domains of the stable characteristic size observed in experiments depends on a few key reactions between receptors and scaffolds. Furthermore, our model suggests novel mechanisms for the alignment of pre- and postsynaptic domains and for short-term postsynaptic plasticity in receptor number. We predict that synaptic receptor domains localize in membrane regions with an increased receptor diffusion coefficient or a decreased scaffold diffusion coefficient. Similarly, we find that activity-dependent increases or decreases in receptor or scaffold diffusion yield a transient increase in the number of receptor molecules concentrated in postsynaptic domains. Thus, the proposed reaction-diffusion model puts forth a coherent set of biophysical mechanisms for the formation, stability, and plasticity of molecular domains on the postsynaptic membrane.

  20. CLASP2-dependent microtubule capture at the neuromuscular junction membrane requires LL5β and actin for focal delivery of acetylcholine receptor vesicles

    NARCIS (Netherlands)

    S. Basu (Saonli); S. Sladecek (Stefan); I.M. De La Peña Y Valenzuela (Isabel Martinez); M. Akaaboune (Mohammed); I. Smal (Ihor); K. Martin (Katrin); N.J. Galjart (Niels); H.R. Brenner (Hans Rudolf)

    2015-01-01

    textabstractA hallmark of the neuromuscular junction (NMJ) is the high density of acetylcholine receptors (AChRs) in the postsynaptic muscle membrane. The postsynaptic apparatus of the NMJ is organized by agrin secreted from motor neurons. The mechanisms that underlie the focal delivery of AChRs to

  1. Multiple personalities: synaptic target cells as introverts and extroverts.

    Science.gov (United States)

    Ritzenthaler, S; Chiba, A

    2001-10-01

    The intricate process of wiring a neuronetwork requires a high degree of accuracy in the communication between pre- and post-synaptic cells. While presynaptic cells have been widely recognized for their dynamic role in synaptic matchmaking, post-synaptic cells have historically been overlooked as passive targets. Recent studies in the Drosophila embryonic neuromuscular system provide compelling evidence that post-synaptic cells participate actively in the synaptogenic process. Endocytosis allows them to quickly modify the array of molecular cues they provide on their surfaces and the extension of dynamic filopodia allows post-synaptic cells to engage in direct long-distance communication. By making use of familiar cellular mechanisms such as endocytosis and filopodia formation, post-synaptic cells may be able to communicate more effectively with potential synaptic partners.

  2. CA1 pyramid-pyramid connections in rat hippocampus in vitro: dual intracellular recordings with biocytin filling.

    Science.gov (United States)

    Deuchars, J; Thomson, A M

    1996-10-01

    In adult rat hippocampus, simultaneous intracellular recordings from 989 pairs of CA1 pyramidal cells revealed nine monosynaptic, excitatory connections. Six of these pairs were sufficiently stable for electrophysiological analysis. Mean excitatory postsynaptic potential amplitude recorded at a postsynaptic membrane potential between -67 and -70 mV was 0.7 +/- 0.5 mV (0.17-1.5 mV), mean 10-90% rise time was 2.7 +/- 0.9 ms (1.5-3.8 ms) and mean width at half-amplitude was 16.8 +/- 4.1 ms (11.6-25 ms). Cells were labelled with biocytin and identified histologically. For one pair that was fully reconstructed morphologically, excitatory postsynaptic potential average amplitude was 1.5 mV, 10-90% rise time 2.8 ms and width at half-amplitude 11.6 ms (at -67 mV). In this pair, correlated light and electron microscopy revealed that the presynaptic axon formed two synaptic contacts with third-order basal dendrites of the postsynaptic pyramid, one with a dendritic spine, the other with a dendritic shaft. In the four pairs tested, postsynaptic depolarization increased excitatory postsynaptic potential amplitude and duration. In two, D-2-amino-5-phosphonovalerate (50 microM) reduced the amplitude and duration of the excitatory postsynaptic potential. The remainder of the excitatory postsynaptic potential now increased with postsynaptic hyperpolarization and was abolished by 20 microM 6-cyano-7-nitroquinoxaline-2,3-dione (n = 1). Paired-pulse depression was evident in the four excitatory postsynaptic potentials tested. This depression decreased with increasing inter-spike interval. These results provide the first combined electrophysiological and morphological illustration of synaptic contacts between pyramidal neurons in the hippocampus and confirm that connections between CA1 pyramidal neurons are mediated by both N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate/kainate receptors.

  3. GABAergic synaptic transmission regulates calcium influx during spike-timing dependent plasticity

    Directory of Open Access Journals (Sweden)

    Trevor Balena

    2010-06-01

    Full Text Available Coincident pre- and postsynaptic activity of hippocampal neurons alters the strength of gamma-aminobutyric acid (GABAA-mediated inhibition through a Ca2+-dependent regulation of cation-chloride cotransporters. This long-term synaptic modulation is termed GABAergic spike-timing dependent plasticity (STDP. In the present study, we examined whether the properties of the GABAergic synapses themselves modulate the required postsynaptic Ca2+ influx during GABAergic STDP induction. To do this we first identified GABAergic synapses between cultured hippocampal neurons based on their relatively long decay time constants and their reversal potentials which lay close to the resting membrane potential. GABAergic STDP was then induced by coincidentally (± 1 ms firing the pre- and postsynaptic neurons at 5 Hz for 30 seconds, while postsynaptic Ca2+ was imaged with the Ca2+-sensitive fluorescent dye Fluo4-AM. In all cases, the induction of GABAergic STDP increased postsynaptic Ca2+ above resting levels. We further found that the magnitude of this increase correlated with the amplitude and polarity of the GABAergic postsynaptic current (GPSC; hyperpolarizing GPSCs reduced the Ca2+ influx in comparison to both depolarizing GPSCs, and postsynaptic neurons spiked alone. This relationship was influenced by both the driving force for Cl- and GABAA conductance (which had positive correlations with the Ca2+ influx. The spike-timing order during STDP induction did not influence the correlation between GPSC amplitude and Ca2+ influx, which is likely accounted for by the symmetrical GABAergic STDP window.

  4. The DLGAP family

    DEFF Research Database (Denmark)

    Rasmussen, Andreas H; Rasmussen, Hanne B; Silahtaroglu, Asli

    2017-01-01

    downstream signalling in the neuron. The postsynaptic density, a highly specialized matrix, which is attached to the postsynaptic membrane, controls this downstream signalling. The postsynaptic density also resets the synapse after each synaptic firing. It is composed of numerous proteins including a family...... in the postsynapse, the DLGAP family seems to play a vital role in synaptic scaling by regulating the turnover of both ionotropic and metabotropic glutamate receptors in response to synaptic activity. DLGAP family has been directly linked to a variety of psychological and neurological disorders. In this review we...... focus on the direct and indirect role of DLGAP family on schizophrenia as well as other brain diseases....

  5. Ontogeny of Biochemical, Morphological and Functional Parameters of Synaptogenesis in Primary Cultures of Rat Hippocampal and Cortical Neurons

    Science.gov (United States)

    AbstractBackground: Synaptogenesis is a critical neurodevelopmental process whereby pre-and postsynaptic neurons form apposed sites of contact specialized for excitatory and inhibitory neurotransmission. Many neurodevelopmental disorders are thought to reflect altered patterns of...

  6. Model of an excitatory synapse based on stochastic processes.

    Science.gov (United States)

    L'Espérance, Pierre-Yves; Labib, Richard

    2013-09-01

    We present a mathematical model of a biological synapse based on stochastic processes to establish the temporal behavior of the postsynaptic potential following a quantal synaptic transmission. This potential form is the basis of the neural code. We suppose that the release of neurotransmitters in the synaptic cleft follows a Poisson process, and that they diffuse according to integrated Ornstein-Uhlenbeck processes in 3-D with random initial positions and velocities. The diffusion occurs in an isotropic environment between two infinite parallel planes representing the pre- and postsynaptic membrane. We state that the presynaptic membrane is perfectly reflecting and that the other is perfectly absorbing. The activation of the receptors polarizes the postsynaptic membrane according to a parallel RC circuit scheme. We present the results obtained by simulations according to a Gillespie algorithm and we show that our model exhibits realistic postsynaptic behaviors from a simple quantal occurrence.

  7. Synapse Pathology in Psychiatric and Neurologic Disease

    NARCIS (Netherlands)

    M. van Spronsen (Myrrhe); C.C. Hoogenraad (Casper)

    2010-01-01

    textabstractInhibitory and excitatory synapses play a fundamental role in information processing in the brain. Excitatory synapses usually are situated on dendritic spines, small membrane protrusions that harbor glutamate receptors and postsynaptic density components and help transmit electrical

  8. Synapse proteomics: current status and quantitative applications

    NARCIS (Netherlands)

    Li, K.W.; Jimenez, C.R.

    2008-01-01

    Chemical synapses are key organelles for neurotransmission. The coordinated actions of protein networks in diverse synaptic subdomains drive the sequential molecular events of transmitter release from the presynaptic bouton, activation of transmitter receptors located in the postsynaptic density and

  9. Probing the mechanism of exocytosis at the hair cell ribbon synapse

    NARCIS (Netherlands)

    Neef, Andreas; Khimich, Darina; Pirih, Primoz; Riedel, Dietmar; Wolf, Fred; Moser, Tobias

    2007-01-01

    Hearing relies on faithful synaptic transmission at the ribbon synapse of cochlear inner hair cells (IHCs). Postsynaptic recordings from this synapse in prehearing animals had delivered strong indications for synchronized release of several vesicles. The underlying mechanism, however, remains

  10. Relating STDP to BCM.

    Science.gov (United States)

    Izhikevich, Eugene M; Desai, Niraj S

    2003-07-01

    We demonstrate that the BCM learning rule follows directly from STDP when pre- and postsynaptic neurons fire uncorrelated or weakly correlated Poisson spike trains, and only nearest-neighbor spike interactions are taken into account.

  11. Evidence that protons act as neurotransmitters at vestibular hair cell-calyx afferent synapses.

    Science.gov (United States)

    Highstein, Stephen M; Holstein, Gay R; Mann, Mary Anne; Rabbitt, Richard D

    2014-04-08

    Present data support the conclusion that protons serve as an important neurotransmitter to convey excitatory stimuli from inner ear type I vestibular hair cells to postsynaptic calyx nerve terminals. Time-resolved pH imaging revealed stimulus-evoked extrusion of protons from hair cells and a subsequent buildup of [H(+)] within the confined chalice-shaped synaptic cleft (ΔpH ∼ -0.2). Whole-cell voltage-clamp recordings revealed a concomitant nonquantal excitatory postsynaptic current in the calyx terminal that was causally modulated by cleft acidification. The time course of [H(+)] buildup limits the speed of this intercellular signaling mechanism, but for tonic signals such as gravity, protonergic transmission offers a significant metabolic advantage over quantal excitatory postsynaptic currents--an advantage that may have driven the proliferation of postsynaptic calyx terminals in the inner ear vestibular organs of contemporary amniotes.

  12. Clipboard

    Indian Academy of Sciences (India)

    Madhsudhan

    dependent second messenger systems which, in turn, regulate post-synaptic activity and local protein synthesis. Abnormal signalling through group I mGluRs have been associated with a series of neurological disorders including Fragile. X syndrome ...

  13. Cannabinoids modulate the P-type high-voltage-activated calcium currents in Purkinje neurons

    NARCIS (Netherlands)

    Fisyunov, A.; Tsintsadze, V.; Min, R.; Burnashev, N.; Lozovaya, N.

    2006-01-01

    Endocannabinoids released by postsynaptic cells inhibit neurotransmitter release in many central synapses by activating presynaptic cannabinoid CB1 receptors. In particular, in the cerebellum, endocannabinoids inhibit synaptic transmission at granule cell to Purkinje cell synapses by modulating

  14. Glycine receptors in CNS neurons as a target for nonretrograde action of cannabinoids

    NARCIS (Netherlands)

    Lozovaya, N.; Yatsenko, N.; Beketov, A.; Tsintsadze, T.; Burnashev, N.

    2005-01-01

    At many central synapses, endocannabinoids released by postsynaptic cells act retrogradely on presynaptic G-protein-coupled cannabinoid receptors to inhibit neurotransmitter release. Here, we demonstrate that cannabinoids may directly affect the functioning of inhibitory glycine receptor (GlyR)

  15. Effects of ACTH4–10 on synaptic transmission in frog sympathetic ganglion

    NARCIS (Netherlands)

    Wouters, W.; Bercken, J. van den

    1979-01-01

    The influenced of ACHT4−10, a behaviourally active fragment of adrenocorticotropic hormone (ACTH) devoid of endocrine activity, on synaptic transmission in the paravertebral sympathetic ganglion of the frog was investigated. Postsynaptic potentials evoked by electrical stimulation of preganglionic

  16. Interaction proteomics reveals brain region-specific AMPA receptor complexes

    NARCIS (Netherlands)

    Chen, N.; Pandya, N.J.; Koopmans, F.T.W.; Castelo-Szekelv, V.; van der Schors, R.C.; Smit, A.B.; Li, K.W.

    2014-01-01

    Fast excitatory synaptic transmission in the brain is mediated by glutamate acting on postsynaptic AMPA receptors. Recent studies have revealed a substantial number of AMPA receptor auxiliary proteins, which potentially contribute to the regulation of AMPA receptor trafficking, subcellular receptor

  17. Generalized Bienenstock-Cooper-Munro rule for spiking neurons that maximizes information transmission.

    Science.gov (United States)

    Toyoizumi, Taro; Pfister, Jean-Pascal; Aihara, Kazuyuki; Gerstner, Wulfram

    2005-04-05

    Maximization of information transmission by a spiking-neuron model predicts changes of synaptic connections that depend on timing of pre- and postsynaptic spikes and on the postsynaptic membrane potential. Under the assumption of Poisson firing statistics, the synaptic update rule exhibits all of the features of the Bienenstock-Cooper-Munro rule, in particular, regimes of synaptic potentiation and depression separated by a sliding threshold. Moreover, the learning rule is also applicable to the more realistic case of neuron models with refractoriness, and is sensitive to correlations between input spikes, even in the absence of presynaptic rate modulation. The learning rule is found by maximizing the mutual information between presynaptic and postsynaptic spike trains under the constraint that the postsynaptic firing rate stays close to some target firing rate. An interpretation of the synaptic update rule in terms of homeostatic synaptic processes and spike-timing-dependent plasticity is discussed.

  18. Differential Inhibitory Control of Semicircular Canal Nerve Afferent-Evoked Inputs in Second-Order Vestibular Neurons by Glycinergic and GABAergic Circuits

    National Research Council Canada - National Science Library

    Stefan Biesdorf; David Malinvaud; Ingrid Reichenberger; Sandra Pfanzelt; Hans Straka

    2008-01-01

    ... (2°VN) sum with disynaptic inhibitory postsynaptic potentials (IPSPs) that originate from the thickest afferent fibers of the same nerve branch and are mediated by neurons in the ipsilateral vestibular nucleus...

  19. Drugs interacting with alpha adrenoceptors

    NARCIS (Netherlands)

    van Zwieten, P. A.

    1989-01-01

    Alpha adrenoceptors should be divided into various subtypes, comprising pre/postsynaptic and alpha 1/alpha 2-subpopulations, respectively. This classification implicates important functional differences between the various alpha-receptor subtypes, including certain differences in signal transduction

  20. Upregulation of transmitter release probability improves a conversion of synaptic analogue signals into neuronal digital spikes

    Science.gov (United States)

    2012-01-01

    Action potentials at the neurons and graded signals at the synapses are primary codes in the brain. In terms of their functional interaction, the studies were focused on the influence of presynaptic spike patterns on synaptic activities. How the synapse dynamics quantitatively regulates the encoding of postsynaptic digital spikes remains unclear. We investigated this question at unitary glutamatergic synapses on cortical GABAergic neurons, especially the quantitative influences of release probability on synapse dynamics and neuronal encoding. Glutamate release probability and synaptic strength are proportionally upregulated by presynaptic sequential spikes. The upregulation of release probability and the efficiency of probability-driven synaptic facilitation are strengthened by elevating presynaptic spike frequency and Ca2+. The upregulation of release probability improves spike capacity and timing precision at postsynaptic neuron. These results suggest that the upregulation of presynaptic glutamate release facilitates a conversion of synaptic analogue signals into digital spikes in postsynaptic neurons, i.e., a functional compatibility between presynaptic and postsynaptic partners. PMID:22852823

  1. Coordinated activation of distinct Ca2+ sources and metabotropic glutamate receptors encodes Hebbian synaptic plasticity

    Science.gov (United States)

    Tigaret, Cezar M.; Olivo, Valeria; Sadowski, Josef H.L.P.; Ashby, Michael C.; Mellor, Jack R.

    2016-01-01

    At glutamatergic synapses, induction of associative synaptic plasticity requires time-correlated presynaptic and postsynaptic spikes to activate postsynaptic NMDA receptors (NMDARs). The magnitudes of the ensuing Ca2+ transients within dendritic spines are thought to determine the amplitude and direction of synaptic change. In contrast, we show that at mature hippocampal Schaffer collateral synapses the magnitudes of Ca2+ transients during plasticity induction do not match this rule. Indeed, LTP induced by time-correlated pre- and postsynaptic spikes instead requires the sequential activation of NMDARs followed by voltage-sensitive Ca2+ channels within dendritic spines. Furthermore, LTP requires inhibition of SK channels by mGluR1, which removes a negative feedback loop that constitutively regulates NMDARs. Therefore, rather than being controlled simply by the magnitude of the postsynaptic calcium rise, LTP induction requires the coordinated activation of distinct sources of Ca2+ and mGluR1-dependent facilitation of NMDAR function. PMID:26758963

  2. Defective synthesis and release of astrocytic thrombospondin-1 mediates the neuronal TDP-43 proteinopathy, resulting in defects in neuronal integrity associated with chronic traumatic encephalopathy: in vitro studies.

    Science.gov (United States)

    Jayakumar, Arumugam Radhakrishnan; Tong, Xiao Y; Shamaladevi, Nagarajarao; Barcelona, Stephanie; Gaidosh, Gabriel; Agarwal, Apeksha; Norenberg, Michael D

    2017-02-01

    Transactivating DNA-binding protein-43 (TDP-43) inclusions and the accumulation of phosphorylated and ubiquitinated tau proteins (p-tau) have been identified in postmortem brain specimens from patients with chronic traumatic encephalopathy (CTE). To examine whether these proteins contribute to the development of CTE, we utilized an in vitro trauma system known to reproduce many of the findings observed in humans and experimental animals with traumatic brain injury. Accordingly, we examined the role of TDP-43 and Tau in an in vitro model of trauma, and determined whether these proteins contribute to the defective neuronal integrity associated with CNS trauma. Single or multiple episodes of trauma to cultured neurons resulted in a time-dependent increase in cytosolic levels of phosphorylated TDP-43 (p-TDP-43). Trauma to cultured neurons also caused an increase in levels of casein kinase 1 epsilon (CK1ε), and ubiquitinated p-TDP-43, along with a decrease in importin-β (all factors known to mediate the "TDP-43 proteinopathy"). Defective neuronal integrity, as evidenced by a reduction in levels of the NR1 subunit of the NMDA receptor, and in PSD95, along with increased levels of phosphorylated tau were also observed. Additionally, increased levels of intra- and extracellular thrombospondin-1 (TSP-1) (a factor known to regulate neuronal integrity) were observed in cultured astrocytes at early stages of trauma, while at later stages decreased levels were identified. The addition of recombinant TSP-1, conditioned media from cultured astrocytes at early stages of trauma, or the CK1ε inhibitor PF4800567 hydrochloride to traumatized cultured neurons reduced levels of p-TDP-43, and reversed the trauma-induced decline in NR1 subunit of the NMDA receptor and PSD95 levels. These findings suggest that a trauma-induced increase in TDP-43 phosphorylation contributes to defective neuronal integrity, and that increasing TSP-1 levels may represent a useful therapeutic approach for

  3. Dynamic changes in neurexins' alternative splicing: role of Rho-associated protein kinases and relevance to memory formation.

    Directory of Open Access Journals (Sweden)

    Gabriela Rozic

    Full Text Available The three neurexins genes (NRXN1/2/3 encode polymorphic synaptic membrane proteins that are involved in cognitive functioning. Neurexins' selectivity of function is presumably conferred through differential use of 2 promoters and 5 alternative splicing sites (SS#1/2/3/4/5. In day-old rat brain neurons grown in culture, activation (depolarization induces reversible, calcium dependent, repression of NRXN2α SS#3 insert. The effects of depolarization on NRXN1/2/3α splicing and biochemical pathways mediating them were further studied in these neurons. NRXN1/2/3α splicing in the course of memory formation in vivo was also explored, using fear conditioning paradigm in rats in which the animals were trained to associate an aversive stimulus (electrical shock with a neutral context (a tone, resulting in the expression of fear responses to the neutral context.In the cultured neurons depolarization induced, beside NRXN2α SS#3, repression of SS#3 and SS#4 exons in NRXN3α but not NRXN1α. The repressions were mediated by the calcium/protein kinase C/Rho-associated protein kinase (ROCK pathway. Fear conditioning induced significant and transient repressions of the NRXN1/2/3α SS#4 exons in the rat hippocampus. ROCK inhibition prior to training attenuated the behavioral fear response, the NRXN1/2/3α splicing repressions and subsequent recovery and the levels of excitatory (PSD95 and inhibitory (gephyrin synaptic proteins in the hippocampus. No such effects were observed in the prefrontal cortex. Significant correlations existed between the fear response and hippocampal NRXN3α and NRXN2α SS#4 inserts as well as PSD95 protein levels. Hippocampal NRXN1α SS#4 insert and gephyrin levels did not correlate with the behavioral response but were negatively correlated with each other.These results show for the first time dynamic, experience related changes in NRXN1/2/3α alternative splicing in the rat brain and a role for ROCK in them. Specific neurexins

  4. Zinc transporters protein level in postmortem brain of depressed subjects and suicide victims.

    Science.gov (United States)

    Rafalo-Ulinska, Anna; Piotrowska, Joanna; Kryczyk, Agata; Opoka, Włodzimierz; Sowa-Kucma, Magdalena; Misztak, Paulina; Rajkowska, Grazyna; Stockmeier, Craig A; Datka, Wojciech; Nowak, Gabriel; Szewczyk, Bernadeta

    2016-12-01

    Major depressive disorder (MDD) is a serious psychiatric illness, associated with an increasing rate of suicide. The pathogenesis of depression may be associated with the disruption of zinc (Zn) homeostasis. In the brain, several proteins that regulate Zn homeostasis are present, including Zn transporters (ZnTs) which remove Zn from the cytosol. The present study was designed to investigate whether depression and suicide are associated with alterations in the expression of the ZnTs protein. Protein levels of ZnT1, ZnT3, ZnT4, ZnT5 and ZnT6 were measured in postmortem brain tissue from two different cohorts. Cohort A contained 10 subjects diagnosed with MDD (7 were suicide victims) and 10 psychiatrically-normal control subjects and cohort B contained 11 non-diagnosed suicide victims and 8 sudden-death control subjects. Moreover, in cohort A we measured protein level of NMDA (GluN2A subunit), AMPA (GluA1 subunit) and 5-HT1A receptors and PSD-95. Proteins were measured in the prefrontal cortex (PFC) using Western blotting. In addition, Zn concentration was measured using a voltammetric method. There was a significant increase in protein levels of ZnT1, ZnT4, ZnT5 in the PFC in MDD, relative to control subjects, while ZnT3 protein level was decreased in MDD. There was no significant difference in the Zn concentration in the PFC between control and MDD subjects. Similarly, in the PFC of suicide victims (non-diagnosed), an increase in protein levels of ZnT1, ZnT4, ZnT5 and ZnT6 was observed. Conversely, protein levels of ZnT3 were decreased in both suicide victims and subjects with MDD, in comparison with control subjects. There was also a significant decrease in the protein level of GluA1, GluN2A, PSD-95 and 5-HT1A in MDD. Our studies suggest that alterations in Zn transport proteins are associated with the pathophysiology of MDD and suicide. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Neo-adjuvant chemotherapy with cisplatin induces low expression of NMDA receptors and postoperative cognitive impairment.

    Science.gov (United States)

    Cheng, Jing; Liu, Xiaoqing; Cao, Longhui; Zhang, Tianhua; Li, Huiting; Lin, Wenqian

    2017-01-10

    Whether Neo-adjuvant chemotherapy can affect patients' postoperative brain function is not clear. In this study, we investigated the effect of preoperative cisplatin treatment on postoperative cognitive function and its possible mechanism in rats. Moreover, we also tested whether the NMDAR inhibitor memantine could attenuate cisplatin-induced alterations. 12-month-oldSprague-Dawley rats randomly received an intraperitoneal injection of either cisplatin once a week at a dose of 3mg/kg for three consecutive weeks or an equivalent volume of normal saline. After the injections, the normal saline injection group was divided into 3 groups (n=5 each): a normal saline group (group S), normal saline+pentobarbital group (group SP), and normal saline+pentobarbital+operation group (group SPO).The cisplatin injection group was divided into 3 groups: a cisplatin group (group C), cisplatin+pentobarbital group (group CP), and cisplatin+pentobarbital+operation group (group CPO).Rats in the group SP, SPO,CP and CPO were anaesthetized with sodium pentobarbital and then the SPO and CPO groups underwent a simple laparotomy operation. The effects of memantine were tested through two additional groups of rats (cisplatin+memantine group (group CM) and cisplatin+pentobarbital+operation+memantine group (group CPOM)). A Morris water maze test was performed to evaluate the spatial learning and memory ability five days after anesthesia or operation. After the test, the hippocampi were removed for detection of the expression of NMDAR by western bloting. The relevant protein expression levels of PSD95 and ERK1/2 were detected by western blot analysis. Rats treated with cisplatin had a longer mean escape latency and spent a shorter amount of time in the target quadrant than did the normal saline injection rats. Furthermore, the protein expression levels of NMDA receptors, PSD95 and ERK1/2 were decreased in cisplatin group and memantine could up-regulate their expression. These results suggest

  6. Neuronal communication: firing spikes with spikes.

    Science.gov (United States)

    Brecht, Michael

    2012-08-21

    Spikes of single cortical neurons can exert powerful effects even though most cortical synapses are too weak to fire postsynaptic neurons. A recent study combining single-cell stimulation with population imaging has visualized in vivo postsynaptic firing in genetically identified target cells. The results confirm predictions from in vitro work and might help to understand how the brain reads single-neuron activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Distinct Roles of Muscle and Motoneuron LRP4 in Neuromuscular Junction Formation

    OpenAIRE

    Wu, Haitao; Lu, Yisheng; Shen, Chengyong; Patel, Neil; Gan, Lin; Xiong, Wen C.; Mei, Lin

    2012-01-01

    Neuromuscular junction (NMJ) formation requires precise interaction between motoneurons and muscle fibers. LRP4 is a receptor of agrin that is thought to act incis to stimulate MuSK in muscle fibers for postsynaptic differentiation. Here we dissected the roles of LRP4 in muscle fibers and motoneurons in NMJ formation by cell-specific mutation. Studies of muscle-specific mutants suggest that LRP4 is involved in deciding where to form AChR clusters in muscle fibers, postsynaptic differentiation...

  8. Single Unit Recordings of Cells Responsive to Visual, Somatic, Acoustic, and Noxious Stimuli in the Superior Colliculus of the Golden Hamster.

    Science.gov (United States)

    1978-08-01

    or skin is touched. This stimulation of the superior colliculus produces excitatory 4 postsynaptic potentials in contralateral neck motoneurons and...inhibi- tory postsynaptic potentials in ipsilateral motoneurons 4 ; conse- quently, the animal turns to the side on which a stimulus occurs. Presumably...Inputs (Chart B): Auditory input arrives in the superior colliculus from the auditory cortex42757 and inferior colliculus73󈨕 . Lesions of the

  9. In vivo imaging of cerebral serotonin transporter and serotonin(2A) receptor binding in 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") and hallucinogen users

    DEFF Research Database (Denmark)

    Erritzoe, David; Frøkjær, Vibe; Holst, Klaus K

    2011-01-01

    Both hallucinogens and 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") have direct agonistic effects on postsynaptic serotonin(2A) receptors, the key site for hallucinogenic actions. In addition, MDMA is a potent releaser and reuptake inhibitor of presynaptic serotonin.......Both hallucinogens and 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") have direct agonistic effects on postsynaptic serotonin(2A) receptors, the key site for hallucinogenic actions. In addition, MDMA is a potent releaser and reuptake inhibitor of presynaptic serotonin....

  10. 不同形式的运动训练对血管性痴呆大鼠学习记忆及海马区突触可塑性的影响%The effect of different types of exercise training on the ability of learning and memory in vascular dementia rats by improving synaptic plasticity in hippocampus

    Institute of Scientific and Technical Information of China (English)

    董军涛; 林阳阳; 燕铁斌; 梁慧英; 吕晓; 何晓阔; 眭明红

    2016-01-01

    目的:观察自主运动、强迫运动和功能性电刺激诱导的运动对血管性痴呆(vascular dementia,VD)大鼠学习记忆、海马区突触可塑性的影响.方法:成年Wistar雄性大鼠,体重250-300g;用10%水合氯醛(300mg/kg)行腹腔注射麻醉,采用双侧颈总动脉永久性结扎法制作血管性痴呆模型.造模成功后大鼠在跑轮中适应3天(剔除运动量不能达到每天270m的大鼠),采用随机数字法分为假手术组、模型组、自主运动组、强迫运动组和功能性电刺激组,每组各8只.假手术组:仅暴露双侧颈总动脉,但不接扎,术后大鼠置于笼中自由活动;模型组:采用双侧颈总动脉永久性结扎法制作VD模型,术后大鼠置于笼中自由活动;自主运动组:造模1周后大鼠在跑轮(直径31.8cm,宽度10cm,旋转阻力约相当于100g物体的重力)上自由运动,用传感器记录跑过的圈数,每天270圈;强迫运动组:造模1周后大鼠在电动跑轮(直径31.8cm,长度40cm,转速9r/min)上运动,每天治疗30min;功能性电刺激组:造模1周后开始治疗,诱导大鼠前肢产生以9m/min行走时的动作,每天治疗30min.以上五组于治疗14d后,采用新奇事物识别实验测试大鼠学习记忆能力.取大鼠海马组织采用Western blot技术检测上述各组SYN、SYP、PSD-95及MAP-2、TAU蛋白表达.采用免疫组织化学染色法检测海马CA1区微管结合蛋白的变化.结果:①新奇事物识别实验:训练阶段各组大鼠对两个相同物体的探寻指数无显著性差异,24h后进行测试,自主运动组、强迫运动组和功能性电刺激组新奇事物认知指数与模型组比较,差异均具有显著性(P<0.05),自主运动组新奇事物认知指数与强迫运动组、功能性电刺激组比较,差异均有显著性(P<0.05),而功能性电刺激组与强迫运动组比较无显著性差异.②海马区SYN、SYP、PSD-95、MAP-2、TAU蛋白表达水平:自主运动组、强迫运动组和功能性电刺激组SYN、PSD

  11. Captodiamine, a putative antidepressant, enhances hypothalamic BDNF expression in vivo by synergistic 5-HT2c receptor antagonism and sigma-1 receptor agonism.

    Science.gov (United States)

    Ring, Rebecca M; Regan, Ciaran M

    2013-10-01

    The putative antidepressant captodiamine is a 5-HT2c receptor antagonist and agonist at sigma-1 and D3 dopamine receptors, exerts an anti-immobility action in the forced swim paradigm, and enhances dopamine turnover in the frontal cortex. Captodiamine has also been found to ameliorate stress-induced anhedonia, reduce the associated elevations of hypothalamic corticotrophin-releasing factor (CRF) and restore the reductions in hypothalamic BDNF expression. Here we demonstrate chronic administration of captodiamine to have no significant effect on hypothalamic CRF expression through sigma-1 receptor agonism; however, both sigma-1 receptor agonism or 5-HT2c receptor antagonism were necessary to enhance BDNF expression. Regulation of BDNF expression by captodiamine was associated with increased phosphorylation of transcription factor CREB and mediated through sigma-1 receptor agonism but blocked by 5-HT2c receptor antagonism. The existence of two separate signalling pathways was confirmed by immunolocalisation of each receptor to distinct cell populations in the paraventricular nucleus of the hypothalamus. Increased BDNF induced by captodiamine was also associated with enhanced expression of synapsin, but not PSD-95, suggesting induction of long-term structural plasticity between hypothalamic synapses. These unique features of captodiamine may contribute to its ability to ameliorate stress-induced anhedonia as the hypothalamus plays a prominent role in regulating HPA axis activity.

  12. Sulforaphane epigenetically enhances neuronal BDNF expression and TrkB signaling pathways.

    Science.gov (United States)

    Kim, Jisung; Lee, Siyoung; Choi, Bo-Ryoung; Yang, Hee; Hwang, Youjin; Park, Jung Han Yoon; LaFerla, Frank M; Han, Jung-Soo; Lee, Ki Won; Kim, Jiyoung

    2017-02-01

    Brain-derived neurotrophic factor (BDNF) is a neurotrophin that supports the survival of existing neurons and encourages the growth and differentiation of new neurons and synapses. We investigated the effect of sulforaphane, a hydrolysis product of glucoraphanin present in Brassica vegetables, on neuronal BDNF expression and its synaptic signaling pathways. Mouse primary cortical neurons and a triple-transgenic mouse model of Alzheimer's disease (3 × Tg-AD) were used to study the effect of sulforaphane. Sulforaphane enhanced neuronal BDNF expression and increased levels of neuronal and synaptic molecules such as MAP2, synaptophysin, and PSD-95 in primary cortical neurons and 3 × Tg-AD mice. Sulforaphane elevated levels of synaptic TrkB signaling pathway components, including CREB, CaMKII, ERK, and Akt in both primary cortical neurons and 3 × Tg-AD mice. Sulforaphane increased global acetylation of histone 3 (H3) and H4, inhibited HDAC activity, and decreased the level of HDAC2 in primary cortical neurons. Chromatin immunoprecipitation analysis revealed that sulforaphane increased acetylated H3 and H4 at BDNF promoters, suggesting that sulforaphane regulates BDNF expression via HDAC inhibition. These findings suggest that sulforaphane has the potential to prevent neuronal disorders such as Alzheimer's disease by epigenetically enhancing neuronal BDNF expression and its TrkB signaling pathways. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Discovery of Cryoprotective Activity in Human Genome-Derived Intrinsically Disordered Proteins

    Directory of Open Access Journals (Sweden)

    Naoki Matsuo

    2018-01-01

    Full Text Available Intrinsically disordered proteins (IDPs are an emerging phenomenon. They may have a high degree of flexibility in their polypeptide chains, which lack a stable 3D structure. Although several biological functions of IDPs have been proposed, their general function is not known. The only finding related to their function is the genetically conserved YSK2 motif present in plant dehydrins. These proteins were shown to be IDPs with the YSK2 motif serving as a core region for the dehydrins’ cryoprotective activity. Here we examined the cryoprotective activity of randomly selected IDPs toward the model enzyme lactate dehydrogenase (LDH. All five IDPs that were examined were in the range of 35–45 amino acid residues in length and were equally potent at a concentration of 50 μg/mL, whereas folded proteins, the PSD-95/Dlg/ZO-1 (PDZ domain, and lysozymes had no potency. We further examined their cryoprotective activity toward glutathione S-transferase as an example of the other enzyme, and toward enhanced green fluorescent protein as a non-enzyme protein example. We further examined the lyophilization protective activity of the peptides toward LDH, which revealed that some IDPs showed a higher activity than that of bovine serum albumin (BSA. Based on these observations, we propose that cryoprotection is a general feature of IDPs. Our findings may become a clue to various industrial applications of IDPs in the future.

  14. RASSF6; the Putative Tumor Suppressor of the RASSF Family

    Directory of Open Access Journals (Sweden)

    Hiroaki Iwasa

    2015-12-01

    Full Text Available Humans have 10 genes that belong to the Ras association (RA domain family (RASSF. Among them, RASSF7 to RASSF10 have the RA domain in the N-terminal region and are called the N-RASSF proteins. In contradistinction to them, RASSF1 to RASSF6 are referred to as the C-RASSF proteins. The C-RASSF proteins have the RA domain in the middle region and the Salvador/RASSF/Hippo domain in the C-terminal region. RASSF6 additionally harbors the PSD-95/Discs large/ZO-1 (PDZ-binding motif. Expression of RASSF6 is epigenetically suppressed in human cancers and is generally regarded as a tumor suppressor. RASSF6 induces caspase-dependent and -independent apoptosis. RASSF6 interacts with mammalian Ste20-like kinases (homologs of Drosophila Hippo and cross-talks with the Hippo pathway. RASSF6 binds MDM2 and regulates p53 expression. The interactions with Ras and Modulator of apoptosis 1 (MOAP1 are also suggested by heterologous protein-protein interaction experiments. RASSF6 regulates apoptosis and cell cycle through these protein-protein interactions, and is implicated in the NF-κB and JNK signaling pathways. We summarize our current knowledge about RASSF6 and discuss what common and different properties RASSF6 and the other C-RASSF proteins have.

  15. Catalpol protects synaptic proteins from beta-amyloid induced neuron injury and improves cognitive functions in aged rats.

    Science.gov (United States)

    Xia, Zhiming; Wang, Fengfei; Zhou, Shuang; Zhang, Rui; Wang, Fushun; Huang, Jason H; Wu, Erxi; Zhang, Yongfang; Hu, Yaer

    2017-09-19

    Synapse loss is one of the common factors contributing to cognitive disorders, such as Alzheimer's disease (AD), which is manifested by the impairment of basic cognitive functions including memory processing, perception, problem solving, and language. The current therapies for patients with cognitive disorders are mainly palliative; thus, regimens preventing and/or delaying dementia progression are urgently needed. In this study, we evaluated the effects of catalpol, isolated from traditional Chinese medicine Rehmannia glutinosa, on synaptic plasticity in aged rat models. We found that catalpol markedly improved the cognitive function of aged male Sprague-Dawley rats and simultaneously increased the expression of synaptic proteins (dynamin 1, PSD-95, and synaptophysin) in the cerebral cortex and hippocampus, respectively. In beta-amyloid (Aβ) injured primary rat's cortical neuron, catalpol did not increase the viability of neuron but extended the length of microtubule-associated protein 2 (MAP-2) positive neurites and reversed the suppressive effects on expression of synaptic proteins induced by Aβ. Additionally, the effects of catalpol on stimulating the growth of MAP-2 positive neurites and the expression of synaptic proteins were diminished by a PKC inhibitor, bisindolylmaleimide I, suggesting that PKC may be implicated in catalpol's function of preventing the neurodegeneration induced by Aβ. Altogether, our study indicates that catalpol could be a potential disease-modifying drug for cognitive disorders such as AD.

  16. big bang gene modulates gut immune tolerance in Drosophila.

    Science.gov (United States)

    Bonnay, François; Cohen-Berros, Eva; Hoffmann, Martine; Kim, Sabrina Y; Boulianne, Gabrielle L; Hoffmann, Jules A; Matt, Nicolas; Reichhart, Jean-Marc

    2013-02-19

    Chronic inflammation of the intestine is detrimental to mammals. Similarly, constant activation of the immune response in the gut by the endogenous flora is suspected to be harmful to Drosophila. Therefore, the innate immune response in the gut of Drosophila melanogaster is tightly balanced to simultaneously prevent infections by pathogenic microorganisms and tolerate the endogenous flora. Here we describe the role of the big bang (bbg) gene, encoding multiple membrane-associated PDZ (PSD-95, Discs-large, ZO-1) domain-containing protein isoforms, in the modulation of the gut immune response. We show that in the adult Drosophila midgut, BBG is present at the level of the septate junctions, on the apical side of the enterocytes. In the absence of BBG, these junctions become loose, enabling the intestinal flora to trigger a constitutive activation of the anterior midgut immune response. This chronic epithelial inflammation leads to a reduced lifespan of bbg mutant flies. Clearing the commensal flora by antibiotics prevents the abnormal activation of the gut immune response and restores a normal lifespan. We now provide genetic evidence that Drosophila septate junctions are part of the gut immune barrier, a function that is evolutionarily conserved in mammals. Collectively, our data suggest that septate junctions are required to maintain the subtle balance between immune tolerance and immune response in the Drosophila gut, which represents a powerful model to study inflammatory bowel diseases.

  17. Characterization of big bang, a novel gene encoding for PDZ domain-containing proteins that are dynamically expressed throughout Drosophila development.

    Science.gov (United States)

    Kim, Sabrina Y; Renihan, Maia K; Boulianne, Gabrielle L

    2006-06-01

    PDZ (PSD-95, Discs-large, ZO-1) domain proteins often function as scaffolding proteins and have been shown to play important roles in diverse cellular processes such as the establishment and maintenance of cell polarity, and signal transduction. Here, we report the identification and cloning of a novel Drosophila melanogaster gene that is predicted to produce several different PDZ domain-containing proteins through alternative promoter usage and alternative splicing. This gene, that we have named big bang (bbg), was first identified as C96-GAL4, a GAL4 enhancer trap line that was generated in our lab. To further characterize bbg, its expression pattern was examined in ovaries, embryos, and late third instar larvae using UAS reporter gene constructs, in situ hybridization, or immunocytochemistry. In addition, the expression of alternatively spliced transcripts was examined in more detail using in situ hybridization. We find that during embryogenesis bbg is predominantly expressed in the developing gut, but it is also expressed in external sensory organs found in the epidermis. In the late third instar larva, bbg is expressed along the presumptive wing margin in the wing disc, broadly in the eye disc, and in other imaginal discs as well as in the brain. The expression patterns observed are dynamic and specific during development, suggesting that like other genes that encode for several different PDZ domain protein isoforms, bbg likely plays important roles in multiple developmental processes.

  18. Chronic dietary creatine enhances hippocampal-dependent spatial memory, bioenergetics, and levels of plasticity-related proteins associated with NF-κB.

    Science.gov (United States)

    Snow, Wanda M; Cadonic, Chris; Cortes-Perez, Claudia; Roy Chowdhury, Subir K; Djordjevic, Jelena; Thomson, Ella; Bernstein, Michael J; Suh, Miyoung; Fernyhough, Paul; Albensi, Benedict C

    2018-02-01

    The brain has a high demand for energy, of which creatine (Cr) is an important regulator. Studies document neurocognitive benefits of oral Cr in mammals, yet little is known regarding their physiological basis. This study investigated the effects of Cr supplementation (3%, w/w) on hippocampal function in male C57BL/6 mice, including spatial learning and memory in the Morris water maze and oxygen consumption rates from isolated mitochondria in real time. Levels of transcription factors and related proteins (CREB, Egr1, and IκB to indicate NF-κB activity), proteins implicated in cognition (CaMKII, PSD-95, and Egr2), and mitochondrial proteins (electron transport chain Complex I, mitochondrial fission protein Drp1) were probed with Western blotting. Dietary Cr decreased escape latency/time to locate the platform (P learning, memory, and mitochondrial function and have important implications for the treatment of diseases affecting memory and energy homeostasis. © 2018 Snow et al.; Published by Cold Spring Harbor Laboratory Press.

  19. Subcellular sorting of the G-protein coupled mouse somatostatin receptor 5 by a network of PDZ-domain containing proteins.

    Directory of Open Access Journals (Sweden)

    Carola Bauch

    Full Text Available PSD-95/discs large/ZO-1 (PDZ domain proteins integrate many G-protein coupled receptors (GPCRs into membrane associated signalling complexes. Additional PDZ proteins are involved in intracellular receptor trafficking. We show that three PDZ proteins (SNX27, PIST and NHERF1/3 regulate the mouse somatostatin receptor subtype 5 (SSTR5. Whereas the PDZ ligand motif of SSTR5 is not necessary for plasma membrane targeting or internalization, it protects the SSTR5 from postendocytic degradation. Under conditions of lysosomal inhibition, recycling of the SSTR5 to the plasma membrane does not depend on the PDZ ligand. However, recycling of the wild type receptor carrying the PDZ binding motif depends on SNX27 which interacts and colocalizes with the receptor in endosomal compartments. PIST, implicated in lysosomal targeting of some membrane proteins, does not lead to degradation of the SSTR5. Instead, overexpressed PIST retains the SSTR5 at the Golgi. NHERF family members release SSTR5 from retention by PIST, allowing for plasma membrane insertion. Our data suggest that PDZ proteins act sequentially on the GPCR at different stages of its subcellular trafficking.

  20. Fragile X Mental Retardation Protein Interactions with a G quadruplex structure in the 3′-Untranslated Region of NR2B mRNA

    Science.gov (United States)

    Stefanovic, Snezana; DeMarco, Brett A.; Underwood, Ayana; Williams, Kathryn R.; Bassell, Gary J.; Mihailescu, Mihaela Rita

    2015-01-01

    Fragile X syndrome, the most common cause of inherited intellectual disability, is caused by a trinucleotide CGG expansion in the 5′-untranslated region of the FMR1 gene, which leads to the loss of expression of the fragile X mental retardation protein (FMRP). FMRP, an RNA-binding protein that regulates the translation of specific mRNAs, has been shown to bind a subset of its mRNA targets by recognizing G quadruplex structures. It has been suggested that FMRP controls the local protein synthesis of several protein components of the Post Synaptic Density (PSD) in response to specific cellular needs. We have previously shown that the interactions between FMRP and mRNAs of the PSD scaffold proteins PSD-95 and Shank1 are mediated via stable G-quadruplex structures formed within the 3′-untranslated regions of these mRNAs. In this study we used biophysical methods to show that a comparable G quadruplex structure forms in the 3′-untranslated region of the glutamate receptor subunit NR2B mRNA encoding for a subunit of N-methyl-D-aspartate (NMDA) receptors that is recognized specifically by FMRP, suggesting a common theme for FMRP recognition of its dendritic mRNA targets. PMID:26412477

  1. Fragile X mental retardation protein interactions with a G quadruplex structure in the 3'-untranslated region of NR2B mRNA.

    Science.gov (United States)

    Stefanovic, Snezana; DeMarco, Brett A; Underwood, Ayana; Williams, Kathryn R; Bassell, Gary J; Mihailescu, Mihaela Rita

    2015-12-01

    Fragile X syndrome, the most common cause of inherited intellectual disability, is caused by a trinucleotide CGG expansion in the 5'-untranslated region of the FMR1 gene, which leads to the loss of expression of the fragile X mental retardation protein (FMRP). FMRP, an RNA-binding protein that regulates the translation of specific mRNAs, has been shown to bind a subset of its mRNA targets by recognizing G quadruplex structures. It has been suggested that FMRP controls the local protein synthesis of several protein components of the post synaptic density (PSD) in response to specific cellular needs. We have previously shown that the interactions between FMRP and mRNAs of the PSD scaffold proteins PSD-95 and Shank1 are mediated via stable G-quadruplex structures formed within the 3'-untranslated regions of these mRNAs. In this study we used biophysical methods to show that a comparable G quadruplex structure forms in the 3'-untranslated region of the glutamate receptor subunit NR2B mRNA encoding for a subunit of N-methyl-d-aspartate (NMDA) receptors that is recognized specifically by FMRP, suggesting a common theme for FMRP recognition of its dendritic mRNA targets.

  2. Prenatal loud music and noise: differential impact on physiological arousal, hippocampal synaptogenesis and spatial behavior in one day-old chicks.

    Science.gov (United States)

    Sanyal, Tania; Kumar, Vivek; Nag, Tapas Chandra; Jain, Suman; Sreenivas, Vishnu; Wadhwa, Shashi

    2013-01-01

    Prenatal auditory stimulation in chicks with species-specific sound and music at 65 dB facilitates spatial orientation and learning and is associated with significant morphological and biochemical changes in the hippocampus and brainstem auditory nuclei. Increased noradrenaline level due to physiological arousal is suggested as a possible mediator for the observed beneficial effects following patterned and rhythmic sound exposure. However, studies regarding the effects of prenatal high decibel sound (110 dB; music and noise) exposure on the plasma noradrenaline level, synaptic protein expression in the hippocampus and spatial behavior of neonatal chicks remained unexplored. Here, we report that high decibel music stimulation moderately increases plasma noradrenaline level and positively modulates spatial orientation, learning and memory of one day-old chicks. In contrast, noise at the same sound pressure level results in excessive increase of plasma noradrenaline level and impairs the spatial behavior. Further, to assess the changes at the molecular level, we have quantified the expression of functional synapse markers: synaptophysin and PSD-95 in the hippocampus. Compared to the controls, both proteins show significantly increased expressions in the music stimulated group but decrease in expressions in the noise group. We propose that the differential increase of plasma noradrenaline level and altered expression of synaptic proteins in the hippocampus are responsible for the observed behavioral consequences following prenatal 110 dB music and noise stimulation.

  3. Consumption of pomegranates improves synaptic function in a transgenic mice model of Alzheimer's disease.

    Science.gov (United States)

    Braidy, Nady; Essa, Musthafa Mohamed; Poljak, Anne; Selvaraju, Subash; Al-Adawi, Samir; Manivasagm, Thamilarasan; Thenmozhi, Arokiasamy Justin; Ooi, Lezanne; Sachdev, Perminder; Guillemin, Gilles J

    2016-10-04

    Alzheimer's Disease (AD) is a progressive neurodegenerative disorder characterized by extracellular plaques containing abnormal Amyloid Beta (Aβ) aggregates, intracellular neurofibrillary tangles containing hyperphosphorylated tau protein, microglia-dominated neuroinflammation, and impairments in synaptic plasticity underlying cognitive deficits. Therapeutic strategies for the treatment of AD are currently limited. In this study, we investigated the effects of dietary supplementation of 4% pomegranate extract to a standard chow diet on neuroinflammation, and synaptic plasticity in APPsw/Tg2576 mice brain. Treatment with a custom mixed diet (pellets) containing 4% pomegranate for 15 months ameliorated the loss of synaptic structure proteins, namely PSD-95, Munc18-1, and SNAP25, synaptophysin, phosphorylation of Calcium/Calmodulin Dependent Protein Kinase IIα (p-CaMKIIα/ CaMKIIα), and phosphorylation of Cyclic AMP-Response Element Binding Protein (pCREB/CREB), inhibited neuroinflammatory activity, and enhanced autophagy, and activation of the phophoinositide-3-kinase-Akt-mammalian target of rapamycin signaling pathway. These neuroprotective effects were associated with reduced β-site cleavage of Amyloid Precursor Protein in APPsw/Tg2576 mice. Therefore, long-term supplementation with pomegranates can attenuate AD pathology by reducing inflammation, and altering APP-dependent processes.

  4. Chronic murine toxoplasmosis is defined by subtle changes in neuronal connectivity

    Directory of Open Access Journals (Sweden)

    Alexandru Parlog

    2014-04-01

    Full Text Available Recent studies correlate chronic Toxoplasma gondii (T. gondii infection with behavioral changes in rodents; additionally, seropositivity in humans is reported to be associated with behavioral and neuropsychiatric diseases. In this study we investigated whether the described behavioral changes in a murine model of chronic toxoplasmosis are associated with changes in synaptic plasticity and brain neuronal circuitry. In mice chronically infected with T. gondii, magnetic resonance imaging (MRI data analysis displayed the presence of heterogeneous lesions scattered throughout all brain areas. However, a higher density of lesions was observed within specific regions such as the somatosensory cortex (SSC. Further histopathological examination of these brain areas indicated the presence of activated resident glia and recruited immune cells accompanied by limited alterations of neuronal viability. In vivo diffusion-tensor MRI analysis of neuronal fiber density within the infected regions revealed connectivity abnormalities in the SSC. Altered fiber density was confirmed by morphological analysis of individual, pyramidal and granule neurons, showing a reduction in dendritic arbor and spine density within the SSC, as well as in the hippocampus. Evaluation of synapse efficacy revealed diminished levels of two key synaptic proteins, PSD95 and synaptophysin, within the same brain areas, indicating deficits in functionality of the synaptic neurotransmission in infected mice. Our results demonstrate that persistent T. gondii infection in a murine model results in synaptic deficits within brain structures leading to disturbances in the morphology of noninfected neurons and modified brain connectivity, suggesting a potential explanation for the behavioral and neuropsychiatric alterations.

  5. Fluoxetine regulates mTOR signalling in a region-dependent manner in depression-like mice.

    Science.gov (United States)

    Liu, Xiao-Long; Luo, Liu; Mu, Rong-Hao; Liu, Bin-Bin; Geng, Di; Liu, Qing; Yi, Li-Tao

    2015-11-02

    Previous studies have demonstrated that the mammalian target of rapamycin (mTOR) signaling pathway has an important role in ketamine-induced, rapid antidepressant effects despite the acute administration of fluoxetine not affecting mTOR phosphorylation in the brain. However, the effects of long-term fluoxetine treatment on mTOR modulation have not been assessed to date. In the present study, we examined whether fluoxetine, a type of commonly used antidepressant agent, alters mTOR signaling following chronic administration in different brain regions, including the frontal cortex, hippocampus, amygdala and hypothalamus. We also investigated whether fluoxetine enhanced synaptic protein levels in these regions via the activation of the mTOR signaling pathway and its downstream regulators, p70S6K and 4E-BP-1. The results indicated that chronic fluoxetine treatment attenuated the chronic, unpredictable, mild stress (CUMS)-induced mTOR phosphorylation reduction in the hippocampus and amygdala of mice but not in the frontal cortex or the hypothalamus. Moreover, the CUMS-decreased PSD-95 and synapsin I levels were reversed by fluoxetine, and these effects were blocked by rapamycin only in the hippocampus. In conclusion, our findings suggest that chronic treatment with fluoxetine can induce synaptic protein expression by activating the mTOR signaling pathway in a region-dependent manner and mainly in the hippocampus.

  6. Investigating the Interactive Effects of Sex Steroid Hormones and Brain-Derived Neurotrophic Factor during Adolescence on Hippocampal NMDA Receptor Expression

    Directory of Open Access Journals (Sweden)

    Cushla R. McCarthny

    2018-01-01

    Full Text Available Sex steroid hormones have neuroprotective properties which may be mediated by brain-derived neurotrophic factor (BDNF. This study sought to determine the interactive effects of preadolescent hormone manipulation and BDNF heterozygosity (+/− on hippocampal NMDA-R expression. Wild-type and BDNF+/− mice were gonadectomised, and females received either 17β-estradiol or progesterone treatment, while males received either testosterone or dihydrotestosterone (DHT treatment. Dorsal (DHP and ventral hippocampus (VHP were dissected, and protein expression of GluN1, GluN2A, GluN2B, and PSD-95 was assessed by Western blot analysis. Significant genotype × OVX interactions were found for GluN1 and GluN2 expression within the DHP of female mice, suggesting modulation of select NMDA-R levels by female sex hormones is mediated by BDNF. Furthermore, within the DHP BDNF+/− mice show a hypersensitive response to hormone treatment on GluN2 expression which may result from upstream alterations in TrkB phosphorylation. In contrast to the DHP, the VHP showed no effects of hormone manipulation but significant effects of genotype on NMDA-R expression. Castration had no effect on NMDA-R expression; however, androgen treatment had selective effects on GluN2B. These data show case distinct, interactive roles for sex steroid hormones and BDNF in the regulation of NMDA-R expression that are dependent on dorsal versus ventral hippocampal region.

  7. Synapse Formation and Cognitive Brain Development: effect of docosahexaenoic (DHA) and other dietary constituents

    Science.gov (United States)

    Wurtman, R. J.

    2008-01-01

    The brain is unusual among organs in that the rates of many of its characteristic enzymatic reactions are controlled by the local concentrations of their substrates, which also happen to be nutrients that cross the blood-brain barrier. Thus, for example, brain levels of tryptophan, tyrosine, or choline can control the rates at which neurons synthesize serotonin, dopamine, or acetylcholine, respectively. The rates at which brain cells produce membrane phospholipids like phosphatidylcholine (PC) are also under such control, both in adult animals and, especially, during early development. If pregnant rats are fed the three dietary constituents needed for PC synthesis - docosahexaenoic acid (DHA), uridine, and choline - starting 10 days before parturition and continuing for 20 days during nursing, brain levels of PC and of the other membrane phosphatides (per cell or per mg protein) are increased by 50% or more. In adult animals this treatment is also known to increase synaptic proteins (e.g. synapsin-l; syntaxin-3; GluR-l; PSD-95) but not ubiquitous proteins like beta-tubulin, and to increase (by 30% or more) the number of dendritic spines on hippocampal neurons. DHA currently is widely used, in human infants, to diminish the negative effects of prematurity on cognitive development. Moreover, DHA, uridine (as UMP), and choline are all found in mother's milk, and included in most infant formulas. It is proposed that these substances are part of a regulatory mechanism through which plasma composition influences brain development. PMID:18803968

  8. The neuronal proteins CIPP, Cypin and IRSp53 form a tripartite complex mediated by PDZ and SH3 domains.

    Science.gov (United States)

    Barilari, Manuela; Dente, Luciana

    2010-10-01

    Here we report the dissection of a tripartite complex formed by CIPP (channel-interacting PDZ protein), IRSp53 (insulin receptor tyrosine kinase substrate protein) and Cypin (cytosolic PSD-95 interactor) in cultured cells. The three proteins are expressed in similar neuronal districts, where CIPP binds to different membrane channels and receptors, IRSp53 regulates the morphogenesis of actin-rich dendritic spines, and Cypin promotes dendrite branching and patterning by binding to tubulin heterodimers. We observed that the interaction among the three proteins is mediated by small binding domains: CIPP works as a bridge, linking the carboxy-termini of IRSp53 and Cypin with its PDZ domains; IRSp53 connects Cypin, through an unusual SH3-mediated association, which can be impaired by substituting two crucial positively charged residues of Cypin. The observation that the three engineered proteins co-localize in the cytoplasm, and at the tip of induced neurites in neuronal cells, raises the interesting possibility that they work together in the formation of neuronal protrusions.

  9. SUMOylation is required for glycine-induced increases in AMPA receptor surface expression (ChemLTP in hippocampal neurons.

    Directory of Open Access Journals (Sweden)

    Nadia Jaafari

    Full Text Available Multiple pathways participate in the AMPA receptor trafficking that underlies long-term potentiation (LTP of synaptic transmission. Here we demonstrate that protein SUMOylation is required for insertion of the GluA1 AMPAR subunit following transient glycine-evoked increase in AMPA receptor surface expression (ChemLTP in dispersed neuronal cultures. ChemLTP increases co-localisation of SUMO-1 and the SUMO conjugating enzyme Ubc9 and with PSD95 consistent with the recruitment of SUMOylated proteins to dendritic spines. In addition, we show that ChemLTP increases dendritic levels of SUMO-1 and Ubc9 mRNA. Consistent with activity dependent translocation of these mRNAs to sites near synapses, levels of the mRNA binding and dendritic transport protein CPEB are also increased by ChemLTP. Importantly, reducing the extent of substrate protein SUMOylation by overexpressing the deSUMOylating enzyme SENP-1 or inhibiting SUMOylation by expressing dominant negative Ubc9 prevent the ChemLTP-induced increase in both AMPAR surface expression and dendritic SUMO-1 mRNA. Taken together these data demonstrate that SUMOylation of synaptic protein(s involved in AMPA receptor trafficking is necessary for activity-dependent increases in AMPAR surface expression.

  10. Prenatal loud music and noise: differential impact on physiological arousal, hippocampal synaptogenesis and spatial behavior in one day-old chicks.

    Directory of Open Access Journals (Sweden)

    Tania Sanyal

    Full Text Available Prenatal auditory stimulation in chicks with species-specific sound and music at 65 dB facilitates spatial orientation and learning and is associated with significant morphological and biochemical changes in the hippocampus and brainstem auditory nuclei. Increased noradrenaline level due to physiological arousal is suggested as a possible mediator for the observed beneficial effects following patterned and rhythmic sound exposure. However, studies regarding the effects of prenatal high decibel sound (110 dB; music and noise exposure on the plasma noradrenaline level, synaptic protein expression in the hippocampus and spatial behavior of neonatal chicks remained unexplored. Here, we report that high decibel music stimulation moderately increases plasma noradrenaline level and positively modulates spatial orientation, learning and memory of one day-old chicks. In contrast, noise at the same sound pressure level results in excessive increase of plasma noradrenaline level and impairs the spatial behavior. Further, to assess the changes at the molecular level, we have quantified the expression of functional synapse markers: synaptophysin and PSD-95 in the hippocampus. Compared to the controls, both proteins show significantly increased expressions in the music stimulated group but decrease in expressions in the noise group. We propose that the differential increase of plasma noradrenaline level and altered expression of synaptic proteins in the hippocampus are responsible for the observed behavioral consequences following prenatal 110 dB music and noise stimulation.

  11. A critical role of CXCR2 PDZ-mediated interactions in endothelial progenitor cell homing and angiogenesis

    Directory of Open Access Journals (Sweden)

    Yuning Hou

    2015-03-01

    Full Text Available Bone marrow-derived endothelial progenitor cells (EPCs contribute to neovessel formation in response to growth factors, cytokines, and chemokines. Chemokine receptor CXCR2 and its cognate ligands are reported to mediate EPC recruitment and angiogenesis. CXCR2 possesses a consensus PSD-95/DlgA/ZO-1 (PDZ motif which has been reported to modulate cellular signaling and functions. Here we examined the potential role of the PDZ motif in CXCR2-mediated EPC motility and angiogenesis. We observed that exogenous CXCR2 C-tail significantly inhibited in vitro EPC migratory responses and angiogenic activities, as well as in vivo EPC angiogenesis. However, the CXCR2 C-tail that lacks the PDZ motif (ΔTTL did not cause any significant changes of these functions in EPCs. In addition, using biochemical assays, we demonstrated that the PDZ scaffold protein NHERF1 specifically interacted with CXCR2 and its downstream effector, PLC-β3, in EPCs. This suggests that NHERF1 might cluster CXCR2 and its relevant signaling molecules into a macromolecular signaling complex modulating EPC cellular functions. Taken together, our data revealed a critical role of a PDZ-based CXCR2 macromolecular complex in EPC homing and angiogenesis, suggesting that targeting this complex might be a novel and effective strategy to treat angiogenesis-dependent diseases.

  12. Oleocanthal ameliorates amyloid-β oligomers' toxicity on astrocytes and neuronal cells: In vitro studies.

    Science.gov (United States)

    Batarseh, Yazan S; Mohamed, Loqman A; Al Rihani, Sweilem B; Mousa, Youssef M; Siddique, Abu Bakar; El Sayed, Khalid A; Kaddoumi, Amal

    2017-06-03

    Extra-virgin olive oil (EVOO) has several health promoting effects. Evidence have shown that EVOO attenuates the pathology of amyloid-β (Aβ) and improves cognitive function in experimental animal models, suggesting it's potential to protect and reduce the risk of developing Alzheimer's disease (AD). Available studies have linked this beneficial effect to oleocanthal, one of the active components in EVOO. The effect of oleocanthal against AD pathology has been linked to its ability to attenuate Aβ and tau aggregation in vitro, and enhance Aβ clearance from the brains of wild-type and AD transgenic mice in vivo. However, the ability of oleocanthal to alter the toxic effect of Aβ on brain parenchymal cells is unknown. In the current study, we investigated oleocanthal effect on modulating Aβ oligomers (Aβo) pathological events in neurons and astrocytes. Our findings demonstrated oleocanthal prevented Aβo-induced synaptic proteins, SNAP-25 and PSD-95, down-regulation in neurons, and attenuated Aβo-induced inflammation, glutamine transporter (GLT1) and glucose transporter (GLUT1) down-regulation in astrocytes. Aβo-induced inflammation was characterized by interleukin-6 (IL-6) increase and glial fibrillary acidic protein (GFAP) upregulation that were reduced by oleocanthal. In conclusion, this study provides further evidence to support the protective effect of EVOO-derived phenolic secoiridoid oleocanthal against AD pathology. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. Structure of the GH1 domain of guanylate kinase-associated protein from Rattus norvegicus

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Junsen; Yang, Huiseon [College of Pharmacy, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Eom, Soo Hyun [School of Life Sciences, Steitz Center for Structural Biology, and Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Chun, ChangJu, E-mail: cchun1130@jnu.ac.kr [College of Pharmacy, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Im, Young Jun, E-mail: imyoungjun@jnu.ac.kr [College of Pharmacy, Chonnam National University, Gwangju 500-757 (Korea, Republic of)

    2014-09-12

    Graphical abstract: - Highlights: • The crystal structure of GKAP homology domain 1 (GH1) was determined. • GKAP GH1 is a three-helix bundle connected by short flexible loops. • The predicted helix α4 associates weakly with the helix α3, suggesting dynamic nature of the GH1 domain. - Abstract: Guanylate-kinase-associated protein (GKAP) is a scaffolding protein that links NMDA receptor-PSD-95 to Shank–Homer complexes by protein–protein interactions at the synaptic junction. GKAP family proteins are characterized by the presence of a C-terminal conserved GKAP homology domain 1 (GH1) of unknown structure and function. In this study, crystal structure of the GH1 domain of GKAP from Rattus norvegicus was determined in fusion with an N-terminal maltose-binding protein at 2.0 Å resolution. The structure of GKAP GH1 displays a three-helix bundle connected by short flexible loops. The predicted helix α4 which was not visible in the crystal structure associates weakly with the helix α3 suggesting dynamic nature of the GH1 domain. The strict conservation of GH1 domain across GKAP family members and the lack of a catalytic active site required for enzyme activity imply that the GH1 domain might serve as a protein–protein interaction module for the synaptic protein clustering.

  14. Vector-mediated expression of erythropoietin improves functional outcome after cervical spinal cord contusion injury.

    Science.gov (United States)

    Wang, S; Wu, Z; Chiang, P; Fink, D J; Mata, M

    2012-09-01

    We evaluated the therapeutic effect of erythropoietin (EPO) delivered by direct injection of a nonreplicating herpes simplex virus (HSV)-based vector coding for EPO (vEPO) in a model of cervical hemicord contusion at C7. At 1 h after spinal cord injury (SCI), either vEPO or control vector carrying a reporter gene (vC) was injected into the cord above and below the lesion. Animals injected with vEPO showed a statistically significant improvement in the ipsilateral forelimb function, as measured by open-field evaluation of motor performance, forelimb reaching in the cylinder test and misplacement in grid walk. This correlated with preservation of gray matter in the area of the lesion. There was also mild but significant improvement of hindlimb motor function measured by Basso-Beattie-Bresnahan score and computerized gait analysis in vEPO compared with control vector-injected animals. Microtubule-associated protein tau, phosphorylated and nonphosphorylated neurofilament protein and the synaptic proteins synaptophysin and PSD-95 were all significantly increased in the spinal cord of vEPO-treated animals compared with control vector-injected animals. These data suggest that gene transfer of EPO after cervical SCI by minimizing the injury size and enhancing tissue sparing preserves large-caliber axons and promotes synaptogenesis.

  15. NMDA receptor GluN2A/GluN2B subunit ratio as synaptic trait of levodopa-induced dyskinesias: from experimental models to patients

    Directory of Open Access Journals (Sweden)

    Manuela eMellone

    2015-07-01

    Full Text Available Levodopa-induced dyskinesias (LIDs are major complications in the pharmacological management of Parkinson’s disease (PD. Abnormal glutamatergic transmission in the striatum is considered a key factor in the development of LIDs. This work aims at i. characterizing NMDA receptor GluN2A/GluN2B subunit ratio as a common synaptic trait in rat and primate models of LIDs and in dyskinetic PD patients, and ii. validating the potential therapeutic effect of a cell-permeable peptide interfering with GluN2A synaptic localization on the dyskinetic behavior of these experimental models of LIDs. Here we demonstrate an altered ratio of synaptic GluN2A/GluN2B-containing NMDA receptors in the striatum of levodopa-treated dyskinetic rats and monkeys as well as in post-mortem tissue from dyskinetic PD patients. The modulation of synaptic NMDA receptor composition by a cell-permeable peptide interfering with GluN2A subunit interaction with the scaffolding protein PSD-95 leads to a reduction in the dyskinetic motor behavior in the two animal models of LIDs. Our results indicate that targeting synaptic NMDA receptor subunit composition may represent an intriguing therapeutic approach aimed at ameliorating levodopa motor side effects.

  16. Prenatal Loud Music and Noise: Differential Impact on Physiological Arousal, Hippocampal Synaptogenesis and Spatial Behavior in One Day-Old Chicks

    Science.gov (United States)

    Sanyal, Tania; Kumar, Vivek; Nag, Tapas Chandra; Jain, Suman; Sreenivas, Vishnu; Wadhwa, Shashi

    2013-01-01

    Prenatal auditory stimulation in chicks with species-specific sound and music at 65 dB facilitates spatial orientation and learning and is associated with significant morphological and biochemical changes in the hippocampus and brainstem auditory nuclei. Increased noradrenaline level due to physiological arousal is suggested as a possible mediator for the observed beneficial effects following patterned and rhythmic sound exposure. However, studies regarding the effects of prenatal high decibel sound (110 dB; music and noise) exposure on the plasma noradrenaline level, synaptic protein expression in the hippocampus and spatial behavior of neonatal chicks remained unexplored. Here, we report that high decibel music stimulation moderately increases plasma noradrenaline level and positively modulates spatial orientation, learning and memory of one day-old chicks. In contrast, noise at the same sound pressure level results in excessive increase of plasma noradrenaline level and impairs the spatial behavior. Further, to assess the changes at the molecular level, we have quantified the expression of functional synapse markers: synaptophysin and PSD-95 in the hippocampus. Compared to the controls, both proteins show significantly increased expressions in the music stimulated group but decrease in expressions in the noise group. We propose that the differential increase of plasma noradrenaline level and altered expression of synaptic proteins in the hippocampus are responsible for the observed behavioral consequences following prenatal 110 dB music and noise stimulation. PMID:23861759

  17. Crystallization and Preliminary Diffraction Analysis of the CAL PDZ Domain in Complex with a Selective Peptide Inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    J Amacher; P Cushing; J Weiner; D Madden

    2011-12-31

    Cystic fibrosis (CF) is associated with loss-of-function mutations in the CF transmembrane conductance regulator (CFTR), which regulates epithelial fluid and ion homeostasis. The CFTR cytoplasmic C-terminus interacts with a number of PDZ (PSD-95/Dlg/ZO-1) proteins that modulate its intracellular trafficking and chloride-channel activity. Among these, the CFTR-associated ligand (CAL) has a negative effect on apical-membrane expression levels of the most common disease-associated mutant {Delta}F508-CFTR, making CAL a candidate target for the treatment of CF. A selective peptide inhibitor of the CAL PDZ domain (iCAL36) has recently been developed and shown to stabilize apical expression of {Delta}F508-CFTR, enhancing net chloride-channel activity, both alone and in combination with the folding corrector corr-4a. As a basis for structural studies of the CAL-iCAL36 interaction, a purification protocol has been developed that increases the oligomeric homogeneity of the protein. Here, the cocrystallization of the complex in space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 35.9, b = 47.7, c = 97.3 {angstrom}, is reported. The crystals diffracted to 1.4 {angstrom} resolution. Based on the calculated Matthews coefficient (1.96 {angstrom}{sup 3} Da{sup -1}), it appears that the asymmetric unit contains two complexes.

  18. The SocioBox: A Novel Paradigm to Assess Complex Social Recognition in Male Mice.

    Science.gov (United States)

    Krueger-Burg, Dilja; Winkler, Daniela; Mitkovski, Mišo; Daher, Fernanda; Ronnenberg, Anja; Schlüter, Oliver M; Dere, Ekrem; Ehrenreich, Hannelore

    2016-01-01

    Impairments in social skills are central to mental disease, and developing tools for their assessment in mouse models is essential. Here we present the SocioBox, a new behavioral paradigm to measure social recognition. Using this paradigm, we show that male wildtype mice of different strains can readily identify an unfamiliar mouse among 5 newly acquainted animals. In contrast, female mice exhibit lower locomotor activity during social exploration in the SocioBox compared to males and do not seem to discriminate between acquainted and unfamiliar mice, likely reflecting inherent differences in gender-specific territorial tasks. In addition to a simple quantification of social interaction time of mice grounded on predefined spatial zones (zone-based method), we developed a set of unbiased, data-driven analysis tools based on heat map representations and characterized by greater sensitivity. First proof-of-principle that the SocioBox allows diagnosis of social recognition deficits is provided using male PSD-95 heterozygous knockout mice, a mouse model related to psychiatric pathophysiology.

  19. Neuroprotection for Stroke: Current Status and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Christoph Kleinschnitz

    2012-09-01

    Full Text Available Neuroprotection aims to prevent salvageable neurons from dying. Despite showing efficacy in experimental stroke studies, the concept of neuroprotection has failed in clinical trials. Reasons for the translational difficulties include a lack of methodological agreement between preclinical and clinical studies and the heterogeneity of stroke in humans compared to homogeneous strokes in animal models. Even when the international recommendations for preclinical stroke research, the Stroke Academic Industry Roundtable (STAIR criteria, were followed, we have still seen limited success in the clinic, examples being NXY-059 and haematopoietic growth factors which fulfilled nearly all the STAIR criteria. However, there are a number of neuroprotective treatments under investigation in clinical trials such as hypothermia and ebselen. Moreover, promising neuroprotective treatments based on a deeper understanding of the complex pathophysiology of ischemic stroke such as inhibitors of NADPH oxidases and PSD-95 are currently evaluated in preclinical studies. Further concepts to improve translation include the investigation of neuroprotectants in multicenter preclinical Phase III-type studies, improved animal models, and close alignment between clinical trial and preclinical methodologies. Future successful translation will require both new concepts for preclinical testing and innovative approaches based on mechanistic insights into the ischemic cascade.

  20. Analysis of primary visual cortex in dementia with Lewy bodies indicates GABAergic involvement associated with recurrent complex visual hallucinations.

    Science.gov (United States)

    Khundakar, Ahmad A; Hanson, Peter S; Erskine, Daniel; Lax, Nichola Z; Roscamp, Joseph; Karyka, Evangelia; Tsefou, Eliona; Singh, Preeti; Cockell, Simon J; Gribben, Andrew; Ramsay, Lynne; Blain, Peter G; Mosimann, Urs P; Lett, Deborah J; Elstner, Matthias; Turnbull, Douglass M; Xiang, Charles C; Brownstein, Michael J; O'Brien, John T; Taylor, John-Paul; Attems, Johannes; Thomas, Alan J; McKeith, Ian G; Morris, Christopher M

    2016-06-30

    Dementia with Lewy bodies (DLB) patients frequently experience well formed recurrent complex visual hallucinations (RCVH). This is associated with reduced blood flow or hypometabolism on imaging of the primary visual cortex. To understand these associations in DLB we used pathological and biochemical analysis of the primary visual cortex to identify changes that could underpin RCVH. Alpha-synuclein or neurofibrillary tangle pathology in primary visual cortex was essentially absent. Neurone density or volume within the primary visual cortex in DLB was also unchanged using unbiased stereology. Microarray analysis, however, demonstrated changes in neuropeptide gene expression and other markers, indicating altered GABAergic neuronal function. Calcium binding protein and GAD65/67 immunohistochemistry showed preserved interneurone populations indicating possible interneurone dysfunction. This was demonstrated by loss of post synaptic GABA receptor markers including gephyrin, GABARAP, and Kif5A, indicating reduced GABAergic synaptic activity. Glutamatergic neuronal signalling was also altered with vesicular glutamate transporter protein and PSD-95 expression being reduced. Changes to the primary visual cortex in DLB indicate that reduced GABAergic transmission may contribute to RCVH in DLB and treatment using targeted GABAergic modulation or similar approaches using glutamatergic modification may be beneficial.

  1. The SocioBox: A novel paradigm to assess complex social recognition in male mice

    Directory of Open Access Journals (Sweden)

    Dilja Krueger-Burg

    2016-08-01

    Full Text Available Impairments in social skills are central to mental disease, and developing tools for their assessment in mouse models is essential. Here we present the SocioBox, a new behavioral paradigm to measure social recognition memory. Using this paradigm, we show that male wildtype mice of different strains can readily identify an unfamiliar mouse among 5 newly acquainted animals. In contrast, female mice exhibit lower locomotor activity during social exploration in the SocioBox compared to males and do not seem to discriminate between acquainted and unfamiliar mice, likely reflecting inherent differences in gender-specific territorial tasks. In addition to a simple quantification of social interaction time of mice grounded on predefined spatial zones (zone-based method, we developed a set of unbiased, data-driven analysis tools based on heat map representations and characterized by greater sensitivity. First proof-of-principle that the SocioBox allows diagnosis of social recognition memory deficits is provided using male PSD-95 heterozygous knockout mice, a mouse model related to psychiatric pathophysiology.

  2. Disrupted-in-schizophrenia1 (DISC1) L100P mutation alters synaptic transmission and plasticity in the hippocampus and causes recognition memory deficits.

    Science.gov (United States)

    Cui, Lin; Sun, Wei; Yu, Ming; Li, Nan; Guo, Li; Gu, Huating; Zhou, Yu

    2016-10-12

    Disrupted-in-schizophrenia 1(DISC1) is a promising candidate susceptibility gene for a spectrum of psychiatric illnesses that share cognitive impairments in common, including schizophrenia, bipolar disorder and major depression. Here we report that DISC1 L100P homozygous mutant shows normal anxiety- and depression-like behavior, but impaired object recognition which is prevented by administration of atypical antipsychotic drug clozapine. Ca2+ image analysis reveals suppression of glutamate-evoked elevation of cytoplasmic [Ca2+] in L100P hippocampal slices. L100P mutant slices exhibit decreased excitatory synaptic transmission (sEPSCs and mEPSCs) in dentate gyrus (DG) and impaired long-term potentiation in the CA1 region of the hippocampus. L100P mutation does not alter proteins expression of the excitatory synaptic markers, PSD95 and synapsin-1; neither does it changes dendrites morphology of primary cultured hippocampal neurons. Our findings suggest that the existence of abnormal synaptic transmission and plasticity in hippocampal network may disrupt declarative information processing and contribute to recognition deficits in DISC1 L100P mutant mice.

  3. Effects of curcumin on chronic, unpredictable, mild, stress-induced depressive-like behaviour and structural plasticity in the lateral amygdala of rats.

    Science.gov (United States)

    Zhang, Lin; Luo, Junxia; Zhang, Minghua; Yao, Wei; Ma, Xuelian; Yu, Shu Yan

    2014-05-01

    Depression is a neuropsychiatric disease associated with wide ranging disruptions in neuronal plasticity throughout the brain. Curcumin, a natural polyphenolic compound of curcuma loga, has been demonstrated to be effective in the treatment of depressive-like disorders. The present study aimed to investigate the mechanisms underlying the antidepressant-like effects of curcumin in a rat model of chronic, unpredictable, mild, stress (CUMS) -induced depression. The results showed that CUMS produced depressive-like behaviours in rats, which were associated with ultra-structural changes in neurons within the lateral amygdala (LA). In addition, the expression of synapse-associated proteins such as brain-derived neurotrophic factor (BDNF), PSD-95 and synaptophysin were significantly decreased in the LA of CUMS-treated rats. Chronic administration of curcumin (40 mg/kg, i.p. 6 wk) before stress exposure significantly prevented these neuronal and biochemical alterations induced by CUMS, and suppressed depressive-like behaviours, suggesting that this neuronal dysregulation may be related to the depressive-like behaviours caused by CUMS. Together with our previous results, the current findings demonstrate that curcumin exhibits neuroprotection and antidepressant-like effects in the CUMS-induced depression model. Furthermore, this antidepressant-like action of curcumin appears to be mediated by modulating synapse-associated proteins within the LA. These findings provide new insights into the underlying mechanisms leading to neural dysfunction in depression and reveal the therapeutic potential for curcumin use in clinical trials.

  4. A pilot study to assess effects of long-term inhalation of airborne particulate matter on early Alzheimer-like changes in the mouse brain.

    Directory of Open Access Journals (Sweden)

    Dhaval P Bhatt

    Full Text Available Exposure to air pollutants, including particulate matter, results in activation of the brain inflammatory response and Alzheimer disease (AD-like pathology in dogs and humans. However, the length of time required for inhalation of ambient particulate matter to influence brain inflammation and AD pathology is less clear. Here, we studied the effect of 3 and 9 months of air particulate matter (<2.5 μm diameter, PM2.5 exposure on brain inflammatory phenotype and pathological hallmarks of AD in C57BL/6 mice. Using western blot, ELISA, and cytokine array analysis we quantified brain APP, beta-site APP cleaving enzyme (BACE, oligomeric protein, total Aβ 1-40 and Aβ 1-42 levels, inducible nitric oxide synthase (iNOS, nitrotyrosine-modified proteins, HNE-Michael adducts, vascular cell adhesion molecule 1 (VCAM-1, glial markers (GFAP, Iba-1, pre- and post- synaptic markers (synaptophysin and PSD-95, cyclooxygenase (COX-1, COX-2 levels, and the cytokine profile in PM2.5 exposed and filtered air control mice. Only 9 month PM2.5 exposure increased BACE protein levels, APP processing, and Aβ 1-40 levels. This correlated with a concomitant increase in COX-1 and COX-2 protein levels and a modest alteration in the cytokine profile. These data support the hypothesis that prolonged exposure to airborne particulate matter has the potential to alter brain inflammatory phenotype and promote development of early AD-like pathology.

  5. The Protective Effect of Icariin on Mitochondrial Transport and Distribution in Primary Hippocampal Neurons from 3× Tg-AD Mice.

    Science.gov (United States)

    Chen, Yijing; Han, Shuangxue; Huang, Xiuxian; Ni, Jiazuan; He, Xiaoyang

    2016-01-27

    Icariin, a pharmacologically active component isolated from the Chinese herb Epimedium, has been shown to improve spatial learning and memory abilities in Alzheimer's disease (AD) rats through inhibition of Aβ production and tau protein hyperphosphorylation. However, the potential mechanism of icariin-induced protective effects against mitochondrial dysfunctions in AD still remains unclear. In the present study, we investigated the effect of icariin on the modulation of mitochondrial transport and distribution in primary hippocampal cultures from triple-transgenic (3× Tg) AD mice. The results showed that icariin enhanced mitochondrial motility and increased mitochondrial index and mitochondrial length and size in the diseased neurons. Additionally, the expression of the key mitochondrial enzyme, pyruvate dehydrogenase-E1α (PDHE1α), and the post synaptic density protein 95 (PSD95), was preserved in AD neurons after icariin treatment, accompanied by a downregulation of Aβ and phosphorylated tau expression in the corresponding areas. Further study showed that icariin treatment resulted in a decrease in mitochondrial fission protein dynamin-related protein 1 (Drp1) and an increase in fusion protein Mitofusin 2 (Mfn2). These data indicate that icariin can promote mitochondrial transport, protect mitochondria against fragmentation and preserve the expression of mitochondrial and synaptic functional proteins in AD neurons. Thus, icariin may be a potential therapeutic complement for AD and other mitochondrial malfunction-related neuronal degenerative diseases.

  6. Neuroprotective Effects of Icariin on Brain Metabolism, Mitochondrial Functions, and Cognition in Triple-Transgenic Alzheimer's Disease Mice.

    Science.gov (United States)

    Chen, Yi-Jing; Zheng, Hai-Yang; Huang, Xiu-Xian; Han, Shuang-Xue; Zhang, Dong-Sheng; Ni, Jia-Zuan; He, Xiao-Yang

    2016-01-01

    This study investigated the neuroprotective properties of icariin (an effective component of traditional Chinese herbal medicine Epimedium) on neuronal function and brain energy metabolism maintenance in a triple-transgenic mouse model of Alzheimer's disease (3 × Tg-AD). 3 × Tg-AD mice as well as primary neurons were subjected to icariin treatment. Morris water maze assay, magnetic resonance spectroscopy (MRS), Western blotting, ELISA, and immunohistochemistry analysis were used to evaluate the effects of icariin administration. Icariin significantly improved spatial learning and memory retention in 3 × Tg-AD mice, promoted neuronal cell activity as identified by the enhancement of brain metabolite N-acetylaspartate level and ATP production in AD mice, preserved the expressions of mitochondrial key enzymes COX IV, PDHE1α, and synaptic protein PSD95, reduced Aβ plaque deposition in the cortex and hippocampus of AD mice, and inhibited β-site APP cleavage enzyme 1 (BACE1) expression. Icariin treatment also decreased the levels of extracellular and intracellular Aβ1-42 in 3 × Tg-AD primary neurons, modulated the distribution of Aβ along the neurites, and protected against mitochondrial fragmentation in 3 × Tg-AD neurons. Icariin shows neuroprotective effects in 3 × Tg-AD mice and may be a promising multitarget drug in the prevention/protection against AD. © 2015 John Wiley & Sons Ltd.

  7. The Protective Effect of Icariin on Mitochondrial Transport and Distribution in Primary Hippocampal Neurons from 3× Tg-AD Mice

    Directory of Open Access Journals (Sweden)

    Yijing Chen

    2016-01-01

    Full Text Available Icariin, a pharmacologically active component isolated from the Chinese herb Epimedium, has been shown to improve spatial learning and memory abilities in Alzheimer’s disease (AD rats through inhibition of Aβ production and tau protein hyperphosphorylation. However, the potential mechanism of icariin-induced protective effects against mitochondrial dysfunctions in AD still remains unclear. In the present study, we investigated the effect of icariin on the modulation of mitochondrial transport and distribution in primary hippocampal cultures from triple-transgenic (3× Tg AD mice. The results showed that icariin enhanced mitochondrial motility and increased mitochondrial index and mitochondrial length and size in the diseased neurons. Additionally, the expression of the key mitochondrial enzyme, pyruvate dehydrogenase-E1α (PDHE1α, and the post synaptic density protein 95 (PSD95, was preserved in AD neurons after icariin treatment, accompanied by a downregulation of Aβ and phosphorylated tau expression in the corresponding areas. Further study showed that icariin treatment resulted in a decrease in mitochondrial fission protein dynamin-related protein 1 (Drp1 and an increase in fusion protein Mitofusin 2 (Mfn2. These data indicate that icariin can promote mitochondrial transport, protect mitochondria against fragmentation and preserve the expression of mitochondrial and synaptic functional proteins in AD neurons. Thus, icariin may be a potential therapeutic complement for AD and other mitochondrial malfunction-related neuronal degenerative diseases.

  8. In Vivo Study of Dynamics and Stability of Dendritic Spines on Olfactory Bulb Interneurons in Xenopus laevis Tadpoles.

    Directory of Open Access Journals (Sweden)

    Yu-Bin Huang

    Full Text Available Dendritic spines undergo continuous remodeling during development of the nervous system. Their stability is essential for maintaining a functional neuronal circuit. Spine dynamics and stability of cortical excitatory pyramidal neurons have been explored extensively in mammalian animal models. However, little is known about spiny interneurons in non-mammalian vertebrate models. In the present study, neuronal morphology was visualized by single-cell electroporation. Spiny neurons were surveyed in the Xenopus tadpole brain and observed to be widely distributed in the olfactory bulb and telencephalon. DsRed- or PSD95-GFP-expressing spiny interneurons in the olfactory bulb were selected for in vivo time-lapse imaging. Dendritic protrusions were classified as filopodia, thin, stubby, or mushroom spines based on morphology. Dendritic spines on the interneurons were highly dynamic, especially the filopodia and thin spines. The stubby and mushroom spines were relatively more stable, although their stability significantly decreased with longer observation intervals. The 4 spine types exhibited diverse preferences during morphological transitions from one spine type to others. Sensory deprivation induced by severing the olfactory nerve to block the input of mitral/tufted cells had no significant effects on interneuron spine stability. Hence, a new model was established in Xenopus laevis tadpoles to explore dendritic spine dynamics in vivo.

  9. Calcium channel-dependent molecular maturation of photoreceptor synapses.

    Directory of Open Access Journals (Sweden)

    Nawal Zabouri

    Full Text Available Several studies have shown the importance of calcium channels in the development and/or maturation of synapses. The Ca(V1.4(α(1F knockout mouse is a unique model to study the role of calcium channels in photoreceptor synapse formation. It features abnormal ribbon synapses and aberrant cone morphology. We investigated the expression and targeting of several key elements of ribbon synapses and analyzed the cone morphology in the Ca(V1.4(α(1F knockout retina. Our data demonstrate that most abnormalities occur after eye opening. Indeed, scaffolding proteins such as Bassoon and RIM2 are properly targeted at first, but their expression and localization are not maintained in adulthood. This indicates that either calcium or the Ca(V1.4 channel, or both are necessary for the maintenance of their normal expression and distribution in photoreceptors. Other proteins, such as Veli3 and PSD-95, also display abnormal expression in rods prior to eye opening. Conversely, vesicle related proteins appear normal. Our data demonstrate that the Ca(V1.4 channel is important for maintaining scaffolding proteins in the ribbon synapse but less vital for proteins related to vesicular release. This study also confirms that in adult retinae, cones show developmental features such as sprouting and synaptogenesis. Overall we present evidence that in the absence of the Ca(V1.4 channel, photoreceptor synapses remain immature and are unable to stabilize.

  10. Hyperactive mTOR signals in the proopiomelanocortin-expressing hippocampal neurons cause age-dependent epilepsy and premature death in mice.

    Science.gov (United States)

    Matsushita, Yuki; Sakai, Yasunari; Shimmura, Mitsunori; Shigeto, Hiroshi; Nishio, Miki; Akamine, Satoshi; Sanefuji, Masafumi; Ishizaki, Yoshito; Torisu, Hiroyuki; Nakabeppu, Yusaku; Suzuki, Akira; Takada, Hidetoshi; Hara, Toshiro

    2016-03-10

    Epilepsy is a frequent comorbidity in patients with focal cortical dysplasia (FCD). Recent studies utilizing massive sequencing data identified subsets of genes that are associated with epilepsy and FCD. AKT and mTOR-related signals have been recently implicated in the pathogenic processes of epilepsy and FCD. To clarify the functional roles of the AKT-mTOR pathway in the hippocampal neurons, we generated conditional knockout mice harboring the deletion of Pten (Pten-cKO) in Proopiomelanocortin-expressing neurons. The Pten-cKO mice developed normally until 8 weeks of age, then presented generalized seizures at 8-10 weeks of age. Video-monitored electroencephalograms detected paroxysmal discharges emerging from the cerebral cortex and hippocampus. These mice showed progressive hypertrophy of the dentate gyrus (DG) with increased expressions of excitatory synaptic markers (Psd95, Shank3 and Homer). In contrast, the expression of inhibitory neurons (Gad67) was decreased at 6-8 weeks of age. Immunofluorescence studies revealed the abnormal sprouting of mossy fibers in the DG of the Pten-cKO mice prior to the onset of seizures. The treatment of these mice with an mTOR inhibitor rapamycin successfully prevented the development of seizures and reversed these molecular phenotypes. These data indicate that the mTOR pathway regulates hippocampal excitability in the postnatal brain.

  11. Early-life stress leads to impaired spatial learning and memory in middle-aged ApoE4-TR mice.

    Science.gov (United States)

    Lin, Lan-Yan; Zhang, Jing; Dai, Xiao-Man; Xiao, Nai-An; Wu, Xi-Lin; Wei, Zhen; Fang, Wen-Ting; Zhu, Yuan-Gui; Chen, Xiao-Chun

    2016-07-12

    Apolipoprotein E (ApoE) is a major lipid carrier that supports lipid transport and injury repair in the brain. The APOE ε4 allele is associated with depression, mild cognitive impairment (MCI) and dementia; however, the precise molecular mechanism through which ApoE4 influences the risk of disease development remains unknown. To address this gap in knowledge, we investigated the potential effects of chronic unpredictable mild stress (CUMS) on ApoE3 and ApoE4 target replacement (ApoE3-TR and ApoE4-TR) mice. All ApoE-TR mice exposed to CUMS at 3 months old recovered from a depression-like state by the age of 12 months. Of note, ApoE4-TR mice, unlike age-matched ApoE3-TR mice, displayed impaired spatial cognitive abilities, loss of GABAergic neurons, decreased expression of Reelin, PSD95, SYN and Fyn, and reduced phosphorylation of NMDAR2B and CREB. These results suggest that early-life stress may mediate cognitive impairment in middle-age ApoE4-TR mice through sustained reduction of GABAergic neurons and Reelin expression, which might further diminish the activation of the Fyn/NMDAR2B signaling pathway.

  12. N-cadherin regulates molecular organization of excitatory and inhibitory synaptic circuits in adult hippocampus in vivo.

    Science.gov (United States)

    Nikitczuk, Jessica S; Patil, Shekhar B; Matikainen-Ankney, Bridget A; Scarpa, Joseph; Shapiro, Matthew L; Benson, Deanna L; Huntley, George W

    2014-08-01

    N-Cadherin and β-catenin form a transsynaptic adhesion complex required for spine and synapse development. In adulthood, N-cadherin mediates persistent synaptic plasticity, but whether the role of N-cadherin at mature synapses is similar to that at developing synapses is unclear. To address this, we conditionally ablated N-cadherin from excitatory forebrain synapses in mice starting in late postnatal life and examined hippocampal structure and function in adulthood. In the absence of N-cadherin, β-catenin levels were reduced, but numbers of excitatory synapses were unchanged, and there was no impact on number or shape of dendrites or spines. However, the composition of synaptic molecules was altered. Levels of GluA1 and its scaffolding protein PSD95 were diminished and the density of immunolabeled puncta was decreased, without effects on other glutamate receptors and their scaffolding proteins. Additionally, loss of N-cadherin at excitatory synapses triggered increases in the density of markers for inhibitory synapses and decreased severity of hippocampal seizures. Finally, adult mutant mice were profoundly impaired in hippocampal-dependent memory for spatial episodes. These results demonstrate a novel function for the N-cadherin/β-catenin complex in regulating ionotropic receptor composition of excitatory synapses, an appropriate balance of excitatory and inhibitory synaptic proteins and the maintenance of neural circuitry necessary to generate flexible yet persistent cognitive and synaptic function. © 2014 Wiley Periodicals, Inc.

  13. Icariin Attenuates Synaptic and Cognitive Deficits in an Aβ1–42-Induced Rat Model of Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Chenxia Sheng

    2017-01-01

    Full Text Available Icariin (ICA, a prenylated flavanol glycoside present in abundant quantities in Epimedium sagittatum, has shown promise in the treatment and prevention of Alzheimer’s disease. Damage to synaptic plasticity induced by amyloid-beta-mediated neurotoxicity is considered a main pathological mechanism driving the learning and memory deficits present in patients with Alzheimer’s disease. This study investigated the neuroprotective effects of icariin in an Aβ1–42-induced rat model of Alzheimer’s disease. Our results showed that Aβ1–42 injection induced loss of learning and memory behaviour in the Morris water maze, which could be reversed with intragastric administration of ICA. Furthermore, ICA reversed decreases in PSD-95, BDNF, pTrkB, pAkt, and pCREB expressions and prevented deterioration of synaptic interface structure. These findings indicate that ICA may improve synaptic plasticity through the BDNF/TrkB/Akt pathway and provide further evidence for its clinical application to improve learning and memory in patients with Alzheimer’s disease.

  14. GABAergic activities control spike timing- and frequency-dependent long-term depression at hippocampal excitatory synapses

    Directory of Open Access Journals (Sweden)

    Makoto Nishiyama

    2010-06-01

    Full Text Available GABAergic interneuronal network activities in the hippocampus control a variety of neural functions, including learning and memory, by regulating θ and γ oscillations. How these GABAergic activities at pre- and post-synaptic sites of hippocampal CA1 pyramidal cells differentially contribute to synaptic function and plasticity during their repetitive pre- and post-synaptic spiking at θ and γ oscillations is largely unknown. We show here that activities mediated by postsynaptic GABAARs and presynaptic GABABRs determine, respectively, the spike timing- and frequency-dependence of activity-induced synaptic modifications at Schaffer collateral-CA1 excitatory synapses. We demonstrate that both feedforward and feedback GABAAR-mediated inhibition in the postsynaptic cell controls the spike timing-dependent long-term depression of excitatory inputs (“e-LTD” at the θ frequency. We also show that feedback postsynaptic inhibition specifically causes e-LTD of inputs that induce small postsynaptic currents (<70 pA with LTP timing, thus enforcing the requirement of cooperativity for induction of long-term potentiation at excitatory inputs (“e-LTP”. Furthermore, under spike-timing protocols that induce e-LTP and e-LTD at excitatory synapses, we observed parallel induction of LTP and LTD at inhibitory inputs (“i-LTP” and “i-LTD” to the same postsynaptic cells. Finally, we show that presynaptic GABABR-mediated inhibition plays a major role in the induction of frequency-dependent e-LTD at α and β frequencies. These observations demonstrate the critical influence of GABAergic interneuronal network activities in regulating the spike timing and frequency dependences of long-term synaptic modifications in the hippocampus.

  15. Rhythms For Cognition: Communication Through Coherence

    Science.gov (United States)

    Fries, Pascal

    2015-01-01

    I propose that synchronization affects communication between neuronal groups. Gamma-band (30-90 Hz) synchronization modulates excitation rapidly enough so it escapes the following inhibition and activates postsynaptic neurons effectively. Synchronization also ensures that a presynaptic activation pattern arrives at postsynaptic neurons in a temporally coordinated manner. At a postsynaptic neuron, multiple presynaptic groups converge, e.g. representing different stimuli. If a stimulus is selected by attention, its neuronal representation shows stronger and higher-frequency gamma-band synchronization. Thereby, the attended stimulus representation selectively entrains postsynaptic neurons. The entrainment creates sequences of short excitation and longer inhibition that are coordinated between pre- and postsynaptic groups to transmit the attended representation and shut out competing inputs. The predominantly bottom-up directed gamma-band influences are controlled by predominantly top-down directed alpha-beta band (8-20 Hz) influences. Attention itself samples stimuli at a 7-8 Hz theta rhythm. Thus, several rhythms and their interplay render neuronal communication effective, precise and selective. PMID:26447583

  16. Short-term plasticity of kainate receptor-mediated EPSCs induced by NMDA receptors at hippocampal mossy fiber synapses.

    Science.gov (United States)

    Rebola, Nelson; Sachidhanandam, Shankar; Perrais, David; Cunha, Rodrigo A; Mulle, Christophe

    2007-04-11

    Kainate receptors (KARs) are heteromeric ionotropic glutamate receptors that play a variety of functions in the regulation of the activity of synaptic networks. Little is known about the regulation of the function of synaptic KARs in the brain. In the present study, we found that a conditioning activation of synaptic NMDA receptors (NMDARs) induces short-term depression of KAR-EPSCs but not of AMPA receptor-EPSCs at synapses between mossy fibers and CA3 pyramidal cells. Short-term depression of KAR-EPSCs by synaptic NMDARs peaked at 1 s and reversed within 20 s, was likely induced and expressed postsynaptically, and was homosynaptic. It depended on a rise of Ca2+ in the postsynaptic cell and on the activation of the phosphatase calcineurin that likely binds to the GluR6b (glutamate receptor subunit 6b) subunit splice variant allowing the dephosphorylation of KARs and inhibition of activity. Finally, we show in the current-clamp mode that short-term depression of KAR-EPSPs is induced by the coincident discharge of action potentials in the postsynaptic cell together with synaptic stimulation. Hence, this study describes a form of short-term synaptic plasticity that is postsynaptic, depends on the temporal order of presynaptic and postsynaptic spiking, and likely affects the summation properties of mossy fiber EPSPs.

  17. Lola regulates glutamate receptor expression at the Drosophila neuromuscular junction

    Directory of Open Access Journals (Sweden)

    Ai Fukui

    2012-02-01

    Communication between pre- and post-synaptic cells is a key process in the development and modulation of synapses. Reciprocal induction between pre- and postsynaptic cells involves regulation of gene transcription, yet the underlying genetic program remains largely unknown. To investigate how innervation-dependent gene expression in postsynaptic cells supports synaptic differentiation, we performed comparative microarray analysis of Drosophila muscles before and after innervation, and of prospero mutants, which show a delay in motor axon outgrowth. We identified 84 candidate genes that are potentially up- or downregulated in response to innervation. By systematic functional analysis, we found that one of the downregulated genes, longitudinals lacking (lola, which encodes a BTB-Zn-finger transcription factor, is required for proper expression of glutamate receptors. When the function of lola was knocked down in muscles by RNAi, the abundance of glutamate receptors (GluRs, GluRIIA, GluRIIB and GluRIII, as well as that of p-21 activated kinase (PAK, was greatly reduced at the neuromuscular junctions (NMJs. Recordings of the synaptic response revealed a decrease in postsynaptic quantal size, consistent with the reduction in GluR levels. Lola appears to regulate the expression of GluRs and PAK at the level of transcription, because the amount of mRNAs encoding these molecules was also reduced in the mutants. The transcriptional level of lola, in turn, is downregulated by increased neural activity. We propose that Lola coordinates expression of multiple postsynaptic components by transcriptional regulation.

  18. LDL-receptor-related protein 4 is crucial for formation of the neuromuscular junction.

    Science.gov (United States)

    Weatherbee, Scott D; Anderson, Kathryn V; Niswander, Lee A

    2006-12-01

    Low-density lipoprotein receptor-related protein 4 (Lrp4) is a member of a family of structurally related, single-pass transmembrane proteins that carry out a variety of functions in development and physiology, including signal transduction and receptor-mediated endocytosis. Lrp4 is expressed in multiple tissues in the mouse, and is important for the proper development and morphogenesis of limbs, ectodermal organs, lungs and kidneys. We show that Lrp4 is also expressed in the post-synaptic endplate region of muscles and is required to form neuromuscular synapses. Lrp4-mutant mice die at birth with defects in both presynaptic and postsynaptic differentiation, including aberrant motor axon growth and branching, a lack of acetylcholine receptor and postsynaptic protein clustering, and a failure to express postsynaptic genes selectively by myofiber synaptic nuclei. Our data show that Lrp4 is required during the earliest events in postsynaptic neuromuscular junction (NMJ) formation and suggest that it acts in the early, nerveindependent steps of NMJ assembly. The identification of Lrp4 as a crucial factor for NMJ formation may have implications for human neuromuscular diseases such as myasthenia syndromes.

  19. Neuromodulated Spike-Timing-Dependent Plasticity, and Theory of Three-Factor Learning Rules

    Science.gov (United States)

    Frémaux, Nicolas; Gerstner, Wulfram

    2016-01-01

    Classical Hebbian learning puts the emphasis on joint pre- and postsynaptic activity, but neglects the potential role of neuromodulators. Since neuromodulators convey information about novelty or reward, the influence of neuromodulators on synaptic plasticity is useful not just for action learning in classical conditioning, but also to decide “when” to create new memories in response to a flow of sensory stimuli. In this review, we focus on timing requirements for pre- and postsynaptic activity in conjunction with one or several phasic neuromodulatory signals. While the emphasis of the text is on conceptual models and mathematical theories, we also discuss some experimental evidence for neuromodulation of Spike-Timing-Dependent Plasticity. We highlight the importance of synaptic mechanisms in bridging the temporal gap between sensory stimulation and neuromodulatory signals, and develop a framework for a class of neo-Hebbian three-factor learning rules that depend on presynaptic activity, postsynaptic variables as well as the influence of neuromodulators. PMID:26834568

  20. Binaural processing in the synthesis of auditory spatial receptive fields.

    Science.gov (United States)

    Peña, José Luis

    2003-11-01

    The owl's auditory system computes interaural time (ITD) and interaural level (ILD) differences to create a two-dimensional map of auditory space. Space-specific neurons are selective for combinations of ITD and ILD, which define, respectively, the horizontal and vertical dimensions of their receptive fields. ITD curves for postsynaptic potentials indicate that ICx neurons integrate the results of binaural cross correlation in different frequency bands. However, the difference between the main and side peaks is slight. ICx neurons further enhance this difference in the process of converting membrane potentials to impulse rates. Comparison of subthreshold postsynaptic potentials (PSPs) and spike output for the same neurons showed that receptive fields measured in PSPs were much larger than those measured in spikes in both ITD and ILD dimensions. A multiplication of separate postsynaptic potentials tuned to ITD and ILD can account for the combination sensitivity of these neurons to ITD-ILD pairs.

  1. Tetanus toxin: convulsant action on mouse spinal cord neurons in culture.

    Science.gov (United States)

    Bergey, G K; MacDonald, R L; Habig, W H; Hardegree, M C; Nelson, P G

    1983-11-01

    The effects of direct application of tetanus toxin on fetal mouse spinal cord neurons in culture are described. Tetanus toxin produces increased excitation characterized by paroxysmal depolarizing events (PDE). In contrast to the abrupt onset of convulsant action produced by postsynaptic glycine antagonist strychnine, the convulsant action of tetanus occurs after a dose-dependent latent period. The onset of the convulsant action of tetanus toxin is paralleled by a reduction in observed spontaneous inhibitory synaptic potentials. Excitatory synaptic events can be identified as components of some tetanus-PDE. The toxin does not alter postsynaptic responses to the inhibitory amino acids glycine and gamma-aminobutyric acid. The latency and convulsant action of tetanus toxin are consistent with an irreversible presynaptic membrane interaction that reduces inhibitory transmission, a mechanism of action distinct from those of convulsants that antagonize inhibitory transmitters at the postsynaptic membrane.

  2. Structural mechanisms of the agrin-LRP4-MuSK signaling pathway in neuromuscular junction differentiation.

    Science.gov (United States)

    Zong, Yinong; Jin, Rongsheng

    2013-09-01

    The neuromuscular junction (NMJ) is the most extensively studied model of neuronal synaptogenesis. Acetylcholine receptor (AChR) clustering on the postsynaptic membrane is a cardinal event in the differentiation of NMJs. AChR clustering and postsynaptic differentiation is orchestrated by sophisticated interactions among three proteins: the neuron-secreted proteoglycan agrin, the co-receptor LRP4, and the muscle-specific receptor tyrosine kinase MuSK. LRP4 and MuSK act as scaffolds for multiple binding partners, resulting in a complex and dynamic network of interacting proteins that is required for AChR clustering. In this review, we discuss the structural basis for NMJ postsynaptic differentiation mediated by the agrin-LRP4-MuSK signaling pathway.

  3. Structural and dielectric properties of the fluorite-type La x Ce1‑x O2‑δ ceramics

    Science.gov (United States)

    Singh, Kushal; Kumar, Kundan; Nayak, Sanjib; Joshi, Deep Chandra; Motakabbir Alom, Mir; Thota, Subhash; Chowdhury, Anirban

    2017-12-01

    High density (95–97%) La x Ce1-x O2-δ (x = 0.1, 0.2 ) ceramics were tested for structural and dielectric properties. Dense microstructure and controlled phase-purity were obtained for all the La3+ -doped samples. A surprising three-fold increase was noticed in the frequency dependent dielectric permittivity \

  4. Comparison of sea snake (Hydrophiidae) neurotoxin to cobra (Naja) neurotoxin.

    Science.gov (United States)

    Komori, Yumiko; Nagamizu, Masaya; Uchiya, Kei-Ichi; Nikai, Toshiaki; Tu, Anthony T

    2009-12-01

    Both sea snakes and cobras have venoms containing postsynaptic neurotoxins. Comparison of the primary structures indicates many similarities, especially the positions of the four disulfide bonds. However, detailed examination reveals differences in several amino acid residues. Amino acid sequences of sea snake neurotoxins were determined, and then compared to cobra neurotoxins by computer modeling. This allowed for easy comparison of the similarities and differences between the two types of postsynaptic neurotoxins. Comparison of computer models for the toxins of sea snakes and cobra will reveal the three dimensional difference of the toxins much clearer than the amino acid sequence alone.

  5. Glutamate gated spiking Neuron Model.

    Science.gov (United States)

    Deka, Krisha M; Roy, Soumik

    2014-01-01

    Biological neuron models mainly analyze the behavior of neural networks. Neurons are described in terms of firing rates viz an analog signal. The Izhikevich neuron model is an efficient, powerful model of spiking neuron. This model is a reduction of Hodgkin-Huxley model to a two variable system and is capable of producing rich firing patterns for many biological neurons. In this paper, the Regular Spiking (RS) neuron firing pattern is used to simulate the spiking of Glutamate gated postsynaptic membrane. Simulation is done in MATLAB environment for excitatory action of synapses. Analogous simulation of spiking of excitatory postsynaptic membrane potential is obtained.

  6. LSD-like panic from risperidone in post-LSD visual disorder.

    Science.gov (United States)

    Abraham, H D; Mamen, A

    1996-06-01

    Risperidone, a novel antipsychotic agent, is an antagonist of postsynaptic serotonin-2 and dopamine D2 receptors. In certain individuals, the hallucinogenic drug lysergic acid diethylamide (LSD) is associated with apparently lifelong continuous visual disturbances, characterized in DSM-IV as hallucinogen-persisting perception disorder (HPPD). Because the hallucinogenic mechanism of LSD is known to act in part at postsynaptic serotonin-2 receptors, it is noteworthy that three HPPD patients treated with risperidone reported an exacerbation of LSD-like panic and visual symptoms. We conclude that HPPD may be a relative contraindication for the use of risperidone.

  7. Increased receptor density of α2 adrenoceptors and GABAA α5 receptors in limbic brain regions in the domoic acid rat model of epilepsy

    DEFF Research Database (Denmark)

    Thomsen, Majken; Lillethorup, Thea Pinholt; Wegener, Gregers

    was significantly increased in the dorsal hippocampus and basolateral amygdala of the DOM rats. A trend towards an increase in the density of α2 adrenoceptors was found throughout the limbic system of the DOM rats compared to controls. Conclusion: Although preliminary, the increase in postsynaptic GABA receptor......, fresh frozen and cut into 20 µM thick slices. Autoradiography was performed using tracers of the α5 subtype of the GABAA receptor ([11C]Ro15-4513) and the α2 adrenoceptors ([3H]RX821002) to determine the binding in limbic brain regions. Results: The binding of postsynaptic GABA receptors...

  8. Deletion of glutamate delta-1 receptor in mouse leads to aberrant emotional and social behaviors.

    Directory of Open Access Journals (Sweden)

    Roopali Yadav

    Full Text Available The delta family of ionotropic glutamate receptors consists of glutamate δ1 (GluD1 and glutamate δ2 (GluD2 receptors. While the role of GluD2 in the regulation of cerebellar physiology is well understood, the function of GluD1 in the central nervous system remains elusive. We demonstrate for the first time that deletion of GluD1 leads to abnormal emotional and social behaviors. We found that GluD1 knockout mice (GluD1 KO were hyperactive, manifested lower anxiety-like behavior, depression-like behavior in a forced swim test and robust aggression in the resident-intruder test. Chronic lithium rescued the depression-like behavior in GluD1 KO. GluD1 KO mice also manifested deficits in social interaction. In the sociability test, GluD1 KO mice spent more time interacting with an inanimate object compared to a conspecific mouse. D-Cycloserine (DCS administration was able to rescue social interaction deficits observed in GluD1 KO mice. At a molecular level synaptoneurosome preparations revealed lower GluA1 and GluA2 subunit expression in the prefrontal cortex and higher GluA1, GluK2 and PSD95 expression in the amygdala of GluD1 KO. Moreover, DCS normalized the lower GluA1 expression in prefrontal cortex of GluD1 KO. We propose that deletion of GluD1 leads to aberrant circuitry in prefrontal cortex and amygdala owing to its potential role in presynaptic differentiation and synapse formation. Furthermore, these findings are in agreement with the human genetic studies suggesting a strong association of GRID1 gene with several neuropsychiatric disorders including schizophrenia, bipolar disorder, autism spectrum disorders and major depressive disorder.

  9. Postoperative intermittent fasting prevents hippocampal oxidative stress and memory deficits in a rat model of chronic cerebral hypoperfusion.

    Science.gov (United States)

    Hu, Yuan; Zhang, Miao; Chen, Yunyun; Yang, Ying; Zhang, Jun-Jian

    2018-01-11

    Whether intermittent fasting (IF) treatment after stroke can prevent its long-term detrimental effects remains unknown. Here, we investigate the effects of postoperative IF on cognitive deficits and its underlying mechanisms in a permanent two-vessel occlusion (2VO) vascular dementia rat model. Rats were subjected to either IF or ad libitum feeding 1 week after 2VO surgery. The cognition of rats was assessed using the novel object recognition (NOR) task and Morris water maze (MWM) 8 weeks after surgery. After behavioral testing, hippocampal malondialdehyde (MDA) and glutathione (GSH) concentrations, superoxide dismutase (SOD) activity, gene expression of antioxidative enzymes, inflammatory protein levels, and microglia density were determined. Postoperative IF significantly ameliorated the cognitive performance of 2VO rats in the NOR and MWM tests. Cognitive enhancement paralleled preservation of the PSD95 and BDNF levels in the 2VO rat hippocampus. Mechanistically, postoperative IF mitigated hippocampal oxidative stress in 2VO rats, as indicated by the reduced MDA concentration and mRNA and the protein levels of the reactive oxygen species-generating enzyme nicotinamide adenine dinucleotide phosphate oxidase 1. IF treatment also preserved the GSH level and SOD activity, as well as the levels of their upstream regulating enzymes, resulting in preserved antioxidative capability. In addition, postoperative IF prevented hippocampal microglial activation and elevation of sphingosine 1-phosphate receptor 1 and inflammatory cytokines in 2VO rats. Our results suggest that postoperative IF suppresses neuroinflammation and oxidative stress induced by chronic cerebral ischemia, thereby preserving cognitive function in a vascular dementia rat model.

  10. Golgi GRASPs: moonlighting membrane tethers

    Directory of Open Access Journals (Sweden)

    Jarvela T

    2012-05-01

    Full Text Available Timothy Jarvela, Adam D LinstedtDepartment of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USAAbstract: The identification of mammalian Golgi reassembly stacking proteins (GRASPs 15 years ago was followed by experiments implicating them in diverse functions, including two differing structural roles in Golgi biogenesis and at least two distinct roles in the secretion of proteins. GRASP55 and GRASP65 are localized to cis and medial/trans Golgi cisternae, respectively. They are both required for stacking of Golgi membranes in a Golgi reassembly assay. Depletion of either GRASP from cultured cells prevents the linking of Golgi membranes into their normal ribbon-like network. While GRASPs are not required for transport of secretory cargo per se, they are required for ER-to-Golgi transport of certain specific cargo, such as those containing a C-terminal valine motif. Surprisingly, GRASPs also promote secretion of cargo by the so-called unconventional secretory pathway, which bypasses the Golgi apparatus where the GRASPs reside. Furthermore, regulation of GRASP activity is now recognized for its connections to cell cycle control, development, and disease. Underlying these diverse activities is the structurally conserved N-terminal GRASP domain whose crystal structure was recently determined. It consists of a tandem array of atypical PSD95–DlgA–Zo–1 (PDZ domains, which are well-known protein–protein interaction motifs. The GRASP PDZ domains are used to localize the proteins to the Golgi as well as GRASP-mediated membrane tethering and cargo interactions. These activities are regulated, in part, by phosphorylation of the large unstructured C-terminal domain.Keywords: GRASP, review, membrane, tether, PDZ domain, secretory chaperone, unconventional secretion

  11. A PDZ-Like Motif in the Biliary Transporter ABCB4 Interacts with the Scaffold Protein EBP50 and Regulates ABCB4 Cell Surface Expression.

    Directory of Open Access Journals (Sweden)

    Quitterie Venot

    Full Text Available ABCB4/MDR3, a member of the ABC superfamily, is an ATP-dependent phosphatidylcholine translocator expressed at the canalicular membrane of hepatocytes. Defects in the ABCB4 gene are associated with rare biliary diseases. It is essential to understand the mechanisms of its canalicular membrane expression in particular for the development of new therapies. The stability of several ABC transporters is regulated through their binding to PDZ (PSD95/DglA/ZO-1 domain-containing proteins. ABCB4 protein ends by the sequence glutamine-asparagine-leucine (QNL, which shows some similarity to PDZ-binding motifs. The aim of our study was to assess the potential role of the QNL motif on the surface expression of ABCB4 and to determine if PDZ domain-containing proteins are involved. We found that truncation of the QNL motif decreased the stability of ABCB4 in HepG2-transfected cells. The deleted mutant ABCB4-ΔQNL also displayed accelerated endocytosis. EBP50, a PDZ protein highly expressed in the liver, strongly colocalized and coimmunoprecipitated with ABCB4, and this interaction required the QNL motif. Down-regulation of EBP50 by siRNA or by expression of an EBP50 dominant-negative mutant caused a significant decrease in the level of ABCB4 protein expression, and in the amount of ABCB4 localized at the canalicular membrane. Interaction of ABCB4 with EBP50 through its PDZ-like motif plays a critical role in the regulation of ABCB4 expression and stability at the canalicular plasma membrane.

  12. Dietary supplementation of soy germ phytoestrogens or estradiol improves spatial memory performance and increases gene expression of BDNF, TrkB receptor and synaptic factors in ovariectomized rats

    Directory of Open Access Journals (Sweden)

    Li Zhuoneng

    2010-09-01

    Full Text Available Abstract Background Estrogen or phytoestrogens treatment has been suggested to improve cognitive function of the brain in postmenopausal women. However, there is lack of information on the mechanism of such treatment on the central nervous system. The present study aimed to determine the effects of estradiol and soy germ phytoestrogens on spatial memory performance in ovariectomized rats and to explore the underlying mechanisms affecting the central nervous system. Methods Ovariectomized Sprague-Dawley rats were fed a basic diet supplemented with soy germ phytoestrogens (0.4 g/kg or 1.6 g/kg or 17β-estradiol (0.15 g/kg for 12 weeks. At the end of the experiment, animals were evaluated for their spatial learning and memory performance by the Morris Water Maze task. The expressions of brain-derived neurotrophic factor (BDNF and synaptic formation proteins in the hippocampal tissue were estimated using RT-PCR and ELISA. Results It was found that rats supplemented with soy germ phytoestrogens or estradiol performed significantly better in spatial memory acquisition and retention when compared to the rats fed on the control diet. Estradiol or the high dose of phytoestrogens treatment significantly increased BDNF concentration and the mRNA levels for BDNF and its TrkB receptors as well as the synaptic formation proteins, synaptophysin, spinophilin, synapsin 1 and PSD-95, in the hippocampal tissue of the experimental animals. It was also found that phytoestrogens, in contrast to estradiol, did not show any significant effect on the vaginal and uteri. Conclusion Soy germ phytoestrogens, which may be a substitute of estradiol, improved spatial memory performance in ovariectomized rats without significant side-effects on the vaginal and uteri. The memory enhancement effect may relate to the increase in BDNF and the synaptic formation proteins expression in the hippocampus of the brain.

  13. Substrate recognition by the cell surface palmitoyl transferase DHHC5.

    Science.gov (United States)

    Howie, Jacqueline; Reilly, Louise; Fraser, Niall J; Vlachaki Walker, Julia M; Wypijewski, Krzysztof J; Ashford, Michael L J; Calaghan, Sarah C; McClafferty, Heather; Tian, Lijun; Shipston, Michael J; Boguslavskyi, Andrii; Shattock, Michael J; Fuller, William

    2014-12-09

    The cardiac phosphoprotein phospholemman (PLM) regulates the cardiac sodium pump, activating the pump when phosphorylated and inhibiting it when palmitoylated. Protein palmitoylation, the reversible attachment of a 16 carbon fatty acid to a cysteine thiol, is catalyzed by the Asp-His-His-Cys (DHHC) motif-containing palmitoyl acyltransferases. The cell surface palmitoyl acyltransferase DHHC5 regulates a growing number of cellular processes, but relatively few DHHC5 substrates have been identified to date. We examined the expression of DHHC isoforms in ventricular muscle and report that DHHC5 is among the most abundantly expressed DHHCs in the heart and localizes to caveolin-enriched cell surface microdomains. DHHC5 coimmunoprecipitates with PLM in ventricular myocytes and transiently transfected cells. Overexpression and silencing experiments indicate that DHHC5 palmitoylates PLM at two juxtamembrane cysteines, C40 and C42, although C40 is the principal palmitoylation site. PLM interaction with and palmitoylation by DHHC5 is independent of the DHHC5 PSD-95/Discs-large/ZO-1 homology (PDZ) binding motif, but requires a ∼ 120 amino acid region of the DHHC5 intracellular C-tail immediately after the fourth transmembrane domain. PLM C42A but not PLM C40A inhibits the Na pump, indicating PLM palmitoylation at C40 but not C42 is required for PLM-mediated inhibition of pump activity. In conclusion, we demonstrate an enzyme-substrate relationship for DHHC5 and PLM and describe a means of substrate recruitment not hitherto described for this acyltransferase. We propose that PLM palmitoylation by DHHC5 promotes phospholipid interactions that inhibit the Na pump.

  14. Splice variants of enigma homolog, differentially expressed during heart development, promote or prevent hypertrophy.

    Science.gov (United States)

    Yamazaki, Tomoko; Wälchli, Sébastien; Fujita, Toshitsugu; Ryser, Stephan; Hoshijima, Masahiko; Schlegel, Werner; Kuroda, Shun'ichi; Maturana, Andrés D

    2010-06-01

    Proteins with a PDZ (for PSD-95, DLG, ZO-1) and one to three LIM (for Lin11, Isl-1, Mec-3) domains are scaffolding sarcomeric and cytoskeletal elements that form structured muscle fibres and provide for the link to intracellular signalling by selectively associating protein kinases, ion channels, and transcription factors with the mechanical stress-strain sensors. Enigma homolog (ENH) is a PDZ-LIM protein with four splice variants: ENH1 with an N-terminal PDZ domain and three C-terminal LIM domains and ENH2, ENH3, and ENH4 without LIM domains. We addressed the functional role of ENH alternative splicing. We studied the expression of the four ENH isoforms in the heart during development and in a mouse model of heart hypertrophy. All four isoforms are expressed in the heart but the pattern of expression is clearly different between embryonic, neonatal, and adult stages. ENH1 appears as the embryonic isoform, whereas ENH2, ENH3, and ENH4 are predominant in adult heart. Moreover, alternative splicing of ENH was changed following induction of heart hypertrophy, producing an ENH isoform pattern similar to that of neonatal heart. Next, we tested a possible causal role of ENH1 and ENH4 in the development of cardiac hypertrophy. When overexpressed in rat neonatal cardiomyocytes, ENH1 promoted the expression of hypertrophy markers and increased cell volume, whereas, on the contrary, ENH4 overexpression prevented these changes. Antagonistic splice variants of ENH may play a central role in the adaptive changes of the link between mechanical stress-sensing and signalling occurring during embryonic development and/or heart hypertrophy.

  15. Inhibition of protein translation by the DISC1-Boymaw fusion gene from a Scottish family with major psychiatric disorders

    Science.gov (United States)

    Ji, Baohu; Higa, Kerin K.; Kim, Minjung; Zhou, Lynn; Young, Jared W.; Geyer, Mark A.; Zhou, Xianjin

    2014-01-01

    The t(1; 11) translocation appears to be the causal genetic lesion with 70% penetrance for schizophrenia, major depression and other psychiatric disorders in a Scottish family. Molecular studies identified the disruption of the disrupted-in-schizophrenia 1 (DISC1) gene by chromosome translocation at chromosome 1q42. Our previous studies, however, revealed that the translocation also disrupted another gene, Boymaw (also termed DISC1FP1), on chromosome 11. After translocation, two fusion genes [the DISC1-Boymaw (DB7) and the Boymaw-DISC1 (BD13)] are generated between the DISC1 and Boymaw genes. In the present study, we report that expression of the DB7 fusion gene inhibits both intracellular NADH oxidoreductase activities and protein translation. We generated humanized DISC1-Boymaw mice with gene targeting to examine the in vivo functions of the fusion genes. Consistent with the in vitro studies on the DB7 fusion gene, protein translation activity is decreased in the hippocampus and in cultured primary neurons from the brains of the humanized mice. Expression of Gad67, Nmdar1 and Psd95 proteins are also reduced. The humanized mice display prolonged and increased responses to the NMDA receptor antagonist, ketamine, on various mouse genetic backgrounds. Abnormal information processing of acoustic startle and depressive-like behaviors are also observed. In addition, the humanized mice display abnormal erythropoiesis, which was reported to associate with depression in humans. Expression of the DB7 fusion gene may reduce protein translation to impair brain functions and thereby contribute to the pathogenesis of major psychiatric disorders. PMID:24908665

  16. Roles for NHERF1 and NHERF2 on the regulation of C3a receptor signaling in human mast cells.

    Directory of Open Access Journals (Sweden)

    Hariharan Subramanian

    Full Text Available BACKGROUND: The anaphylatoxin C3a binds to the G protein coupled receptor (GPCR, C3aR and activates divergent signaling pathways to induce degranulation and cytokine production in human mast cells. Adapter proteins such as the Na(+/H(+ exchange regulatory factor (NHERF1 and NHERF2 have been implicated in regulating functions of certain GPCRs by binding to the class I PDZ (PSD-95/Dlg/Zo1 motifs present on their cytoplasmic tails. Although C3aR possesses a class I PDZ motif, the possibility that it interacts with NHERF proteins to modulate signaling in human mast cells has not been determined. METHODOLOGY/PRINCIPAL FINDINGS: Using reverse transcription PCR and Western blotting, we found that NHERF1 and NHERF2 are expressed in human mast cell lines (HMC-1, LAD2 and CD34(+-derived primary human mast cells. Surprisingly, however, C3aR did not associate with these adapter proteins. To assess the roles of NHERFs on signaling downstream of C3aR, we used lentiviral shRNA to stably knockdown the expression of these proteins in human mast cells. Silencing the expression of NHERF1 and NHERF2 had no effect on C3aR desensitization, agonist-induced receptor internalization, ERK/Akt phosphorylation or chemotaxis. However, loss of NHERF1 and NHERF2 resulted in significant inhibition of C3a-induced mast cell degranulation, NF-κB activation and chemokine production. CONCLUSION/SIGNIFICANCE: This study demonstrates that although C3aR possesses a class I PDZ motif, it does not associate with NHERF1 and NHERF2. Surprisingly, these proteins provide stimulatory signals for C3a-induced degranulation, NF-κB activation and chemokine generation in human mast cells. These findings reveal a new level of complexity for the functional regulation of C3aR by NHERFs in human mast cells.

  17. Physical Exercise Promotes Novel Object Recognition Memory in Spontaneously Hypertensive Rats after Ischemic Stroke by Promoting Neural Plasticity in the Entorhinal Cortex

    Directory of Open Access Journals (Sweden)

    Xiaona Pan

    2017-11-01

    Full Text Available Cerebral ischemia leads to memory impairment, and several studies have indicated that physical exercise (PE has memory-improving effects after ischemia. This study was designed to further explore the specific role of PE in novel object recognition (NOR memory after stroke and the exact cortical regions in which memory is restored by PE. Spontaneously hypertensive rats (SHR were subjected to transient middle cerebral artery occlusion (tMCAO or sham surgery, followed by 26 days of PE starting on day 3 post-tMCAO. Thereafter, infarct volume, neurobehavioral outcome and NOR memory were assessed. Immunofluorescence staining and Luxol Fast Blue (LFB staining were performed in the prefrontal cortex, entorhinal cortex and corpus callosum regions. Western blot analysis was performed to detect expressions of Nestin, Bcl-2 and SYN proteins in the entorhinal cortex. After tMCAO, NOR memory impairment was found in SHR. Rats subjected to PE post-tMCAO showed increased discrimination ratio, as well as significant decreases in infarct volumes and modified neurological severity scores (mNSS, when compared with tMCAO rats without PE. After stroke, NeuN-positive cell number was drastically reduced in the entorhinal cortex, rather than in the prefrontal cortex. Ischemic stroke had no impact on myelin and phospholipids, and the ratio of SMI-32/MBP in the corpus callosum. PE increased NeuN, Nestin, Ki67, MBP, SYN, PSD-95 and Bcl-2 expressions in the entorhinal cortex, while TUNEL and SMI-32 expressions were decreased. In conclusion, the NOR memory-improving capacity promoted by PE was closely related to neuronal cell proliferation and synaptic plasticity of the entorhinal cortex.

  18. A novel synaptic junction preparation for the identification and characterization of cleft proteins

    Science.gov (United States)

    Tao-Cheng, Jung-Hwa; Dosemeci, Ayse

    2017-01-01

    Identification of synaptic cleft components has been hampered by the lack of a suitable preparation enriched in synaptic junctions devoid of adjoining peripheral membranes. Prior strategies for the isolation of synaptic junctions, relying on detergents for the removal of peripheral membranes, resulted in substantial loss of membranes lining the cleft. Here, a novel, detergent-free method is described for the preparation of a synaptic junction (SJ) fraction, using phospholipase A2. Limited digestion of synaptic plasma membrane (SPM) fraction with phospholipase A2 followed by centrifugation over a sucrose cushion results in selective removal of membranes peripheral to the cleft while junctional membranes remain relatively intact as observed by electron microscopy. Enrichment in synaptic junctional structures and loss of membranes peripheral to the junctional area are further verified by demonstrating enrichment in PSD-95 and loss in mGluR5, respectively. The SJ fraction is enriched in neuroligins and neurexins, in agreement with immuno-electron microscopy data showing their selective localization to the junctional area. Among additional cell adhesion molecules tested, N-cadherin and specific isoforms of the SynCAM and SALM families also show marked enrichment in the SJ fraction, suggesting preferential localization at the synaptic cleft while others show little enrichment or decrease, suggesting that they are not restricted to or concentrated at the synaptic cleft. Treatment of the SJ fraction with glycosidases results in electrophoretic mobility shifts of all cell adhesion molecules tested, indicating glycosylation at the synaptic cleft. Biochemical and ultrastructural data presented indicate that the novel synaptic junction preparation can be used as a predictive tool for the identification and characterization of the components of the synaptic cleft. PMID:28362857

  19. Transient alteration of the vestibular calyceal junction and synapse in response to chronic ototoxic insult in rats

    Directory of Open Access Journals (Sweden)

    Lara Sedó-Cabezón

    2015-10-01

    Full Text Available Ototoxicity is known to cause permanent loss of vestibule function through degeneration of sensory hair cells (HCs. However, functional recovery has been reported during washout after chronic ototoxicity, although the mechanisms underlying this reversible dysfunction are unknown. Here, we study this question in rats chronically exposed to the ototoxic compound 3,3′-iminodipropionitrile (IDPN. Pronounced alterations in vestibular function appeared before significant loss of HCs or stereociliary coalescence became evident by ultrastructural analyses. This early dysfunction was fully reversible if the exposure was terminated promptly. In cristae and utricles, the distinct junctions formed between type I HCs (HCI and calyx endings were completely dismantled at these early stages of reversible dysfunction, and completely rebuilt during washout. Immunohistochemical observations revealed loss and recovery of the junction proteins CASPR1 and tenascin-C and RT-PCR indicated that their loss was not due to decreased gene expression. KCNQ4 was mislocalized during intoxication and recovered control-like localization after washout. At early stages of the intoxication, the calyces could be classified as showing intact or lost junctions, indicating that calyceal junction dismantlement is triggered on a calyx-by-calyx basis. Chronic toxicity also altered the presence of ribeye, PSD-95 and GluA2 puncta in the calyces. These synaptic alterations varied between the two types of calyx endings (formed by calyx-only or dimorphic afferents and some persisted at the end of the washout period. The present data reveal new forms of plasticity of the calyx endings in adult mammals, including a robust capacity for rebuilding the calyceal junction. These findings contribute to a better understanding of the phenomena involved in progressive vestibular dysfunction and its potential recovery during and after ototoxic exposure.

  20. Proteomic analysis reveals novel ligands and substrates for LNX1 E3 ubiquitin ligase.

    Directory of Open Access Journals (Sweden)

    Joan A Lenihan

    Full Text Available Ligand of Numb protein X1 (LNX1 is an E3 ubiquitin ligase that contains a catalytic RING (Really Interesting New Gene domain and four PDZ (PSD-95, DlgA, ZO-1 domains. LNX1 can ubiquitinate Numb, as well as a number of other ligands. However, the physiological relevance of these interactions in vivo remain unclear. To gain functional insights into the LNX family, we have characterised the LNX1 interactome using affinity purification and mass spectrometry. This approach identified a large number of novel LNX1-interacting proteins, as well as confirming known interactions with NUMB and ERC2. Many of the novel interactions mapped to the LNX PDZ domains, particularly PDZ2, and many showed specificity for LNX1 over the closely related LNX2. We show that PPFIA1 (liprin-α1, KLHL11, KIF7 and ERC2 are substrates for ubiquitination by LNX1. LNX1 ubiquitination of liprin-α1 is dependent on a PDZ binding motif containing a carboxyl terminal cysteine that binds LNX1 PDZ2. Surprisingly, the neuronally-expressed LNX1p70 isoform, that lacks the RING domain, was found to promote ubiquitination of PPFIA1 and KLHL11, albeit to a lesser extent than the longer RING-containing LNX1p80 isoform. Of several E3-ligases identified in the LNX1 interactome we confirm interactions of LNX1 with MID2/TRIM1 and TRIM27. On this basis we propose a model whereby LNX1p70, despite lacking a catalytic RING domain, may function as a scaffold to promote ubiquitination of its ligands through recruitment of other E3-ligases. These findings provide functional insights into the LNX protein family, particularly the neuronal LNX1p70 isoform.

  1. Valproic Acid Induces Telomerase Reverse Transcriptase Expression during Cortical Development.

    Science.gov (United States)

    Kim, Ki Chan; Choi, Chang Soon; Gonzales, Edson Luck T; Mabunga, Darine Froy N; Lee, Sung Hoon; Jeon, Se Jin; Hwangbo, Ram; Hong, Minha; Ryu, Jong Hoon; Han, Seol-Heui; Bahn, Geon Ho; Shin, Chan Young

    2017-10-01

    The valproic acid (VPA)-induced animal model is one of the most widely utilized environmental risk factor models of autism. Autism spectrum disorder (ASD) remains an insurmountable challenge among neurodevelopmental disorders due to its heterogeneity, unresolved pathological pathways and lack of treatment. We previously reported that VPA-exposed rats and cultured rat primary neurons have increased Pax6 expression during post-midterm embryonic development which led to the sequential upregulation of glutamatergic neuronal markers. In this study, we provide experimental evidence that telomerase reverse transcriptase (TERT), a protein component of ribonucleoproteins complex of telomerase, is involved in the abnormal components caused by VPA in addition to Pax6 and its downstream signals. In embryonic rat brains and cultured rat primary neural progenitor cells (NPCs), VPA induced the increased expression of TERT as revealed by Western blot, RT-PCR, and immunostainings. The HDAC inhibitor property of VPA is responsible for the TERT upregulation. Chromatin immunoprecipitation revealed that VPA increased the histone acetylation but blocked the HDAC1 binding to both Pax6 and Tert genes. Interestingly, the VPA-induced TERT overexpression resulted to sequential upregulations of glutamatergic markers such as Ngn2 and NeuroD1, and inter-synaptic markers such as PSD-95, α-CaMKII, vGluT1 and synaptophysin. Transfection of Tert siRNA reversed the effects of VPA in cultured NPCs confirming the direct involvement of TERT in the expression of those markers. This study suggests the involvement of TERT in the VPA-induced autistic phenotypes and has important implications for the role of TERT as a modulator of balanced neuronal development and transmission in the brain.

  2. The multivalent PDZ domain-containing protein CIPP is a partner of acid-sensing ion channel 3 in sensory neurons.

    Science.gov (United States)

    Anzai, Naohiko; Deval, Emmanuel; Schaefer, Lionel; Friend, Valerie; Lazdunski, Michel; Lingueglia, Eric

    2002-05-10

    Acid-sensing ion channels (ASICs) are cationic channels activated by extracellular pH. They are present in the brain, where they are thought to participate in signal transduction associated with local pH variations, and in sensory neurons, where they have been involved in pain perception associated with tissue acidosis and in mechanoperception. The ASIC3 subunit is mainly expressed in dorsal root ganglion neurons. Its expression is associated with a rapidly inactivating current followed by a slowly activating sustained current thought to be required for the tonic sensation of pain caused by acids. We report here the interaction of this channel subunit with the multivalent PDZ (PSD-95 Drosophila discs-large protein, Zonula occludens protein 1) domain-containing protein CIPP. This interaction requires the C-terminal region of ASIC3 and the fourth PDZ domain of CIPP. Co-expression of CIPP and ASIC3 in COS cells increases the maximal ASIC3 peak current density by a factor of 5 and slightly shifts the pH(0.5) for activation from pH 6.2 to pH 6.4. CIPP mRNA is found at a significant level in the same dorsal root ganglion neuronal cell population that expresses the ASIC3 subunit, i.e. mainly in the small nociceptive neurons. CIPP is thus a scaffolding protein that could both enhance the surface expression of ASIC3 and bring together ASIC3 and functionally related proteins in the membrane of sensory neurons.

  3. Andrographolide - A promising therapeutic agent, negatively regulates glial cell derived neurodegeneration of prefrontal cortex, hippocampus and working memory impairment.

    Science.gov (United States)

    Das, Sudeshna; Mishra, K P; Ganju, Lilly; Singh, S B

    2017-12-15

    Over activation of glial cell derived innate immune factors induces neuro-inflammation that results in neurodegenerative disease, like working memory impairment. In this study, we have investigated the role of andrographolide, a major constituent of Andrographis paniculata plant, in reduction of reactive glial cell derived working memory impairment. Real time PCR, Western bloting, flow cytometric and immunofluorescence studies demonstrated that andrographolide inhibited lipopolysaccharide (LPS)-induced overexpression of HMGB1, TLR4, NFκB, COX-2, iNOS, and release of inflammatory mediators in primary mix glial culture, adult mice prefrontal cortex and hippocampus region. Active microglial and reactive astrocytic makers were also downregulated after andrographolide treatment. Andrographolide suppressed overexpression of microglial MIP-1α, P2X7 receptor and its downstream signaling mediators including-inflammasome NLRP3, caspase1 and mature IL-1β. Furthermore, in vivo maze studies suggested that andrographolide treatment reversed LPS-induced behavioural and working memory disturbances including regulation of expression of protein markers like PKC, p-CREB, amyloid beta, APP, p-tau, synapsin and PSD-95. Andrographolide, by lowering expression of pro apoptotic genes and enhancing the expression of anti-apoptotic gene showed its anti-apoptotic nature that in turn reduces neurodegeneration. Morphology studies using Nissl and FJB staining also showed the neuroprotective effect of andrographolide in the prefrontal cortex region. The above studies indicated that andrographolide prevented neuroinflammation-associated neurodegeneration and improved synaptic plasticity markers in cortical as well as hippocampal region which suggests that andrographolide could be a novel pharmacological countermeasure for the treatment of neuroinflammation and neurological disorders related to memory impairment. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Differential effects of prenatal chronic high-decibel noise and music exposure on the excitatory and inhibitory synaptic components of the auditory cortex analog in developing chicks (Gallus gallus domesticus).

    Science.gov (United States)

    Kumar, V; Nag, T C; Sharma, U; Jagannathan, N R; Wadhwa, S

    2014-06-06

    Proper development of the auditory cortex depends on early acoustic experience that modulates the balance between excitatory and inhibitory (E/I) circuits. In the present social and occupational environment exposure to chronic loud sound in the form of occupational or recreational noise, is becoming inevitable. This could especially disrupt the functional auditory cortex development leading to altered processing of complex sound and hearing impairment. Here we report the effects of prenatal chronic loud sound (110-dB sound pressure level (SPL)) exposure (rhythmic [music] and arrhythmic [noise] forms) on the molecular components involved in regulation of the E/I balance in the developing auditory cortex analog/Field L (AuL) in domestic chicks. Noise exposure at 110-dB SPL significantly enhanced the E/I ratio (increased expression of AMPA receptor GluR2 subunit and glutamate with decreased expression of GABA(A) receptor gamma 2 subunit and GABA), whereas loud music exposure maintained the E/I ratio. Expressions of markers of synaptogenesis, synaptic stability and plasticity i.e., synaptophysin, PSD-95 and gephyrin were reduced with noise but increased with music exposure. Thus our results showed differential effects of prenatal chronic loud noise and music exposures on the E/I balance and synaptic function and stability in the developing auditory cortex. Loud music exposure showed an overall enrichment effect whereas loud noise-induced significant alterations in E/I balance could later impact the auditory function and associated cognitive behavior. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. Cognition and Synaptic-Plasticity Related Changes in Aged Rats Supplemented with 8- and 10-Carbon Medium Chain Triglycerides.

    Directory of Open Access Journals (Sweden)

    Dongmei Wang

    Full Text Available Brain glucose hypometabolism is a common feature of Alzheimer's disease (AD. Previous studies have shown that cognition is improved by providing AD patients with an alternate energy source: ketones derived from either ketogenic diet or supplementation with medium chain triglycerides (MCT. Recently, data on the neuroprotective capacity of MCT-derived medium chain fatty acids (MCFA suggest 8-carbon and 10-carbon MCFA may have cognition-enhancing properties which are not related to ketone production. We investigated the effect of 8 week treatment with MCT8, MCT10 or sunflower oil supplementation (5% by weight of chow diet in 21 month old Wistar rats. Both MCT diets increased ketones plasma similarly compared to control diet, but MCT diets did not increase ketones in the brain. Treatment with MCT10, but not MCT8, significantly improved novel object recognition memory compared to control diet, while social recognition increased in both MCT groups. MCT8 and MCT10 diets decreased weight compared to control diet, where MCFA plasma levels were higher in MCT10 groups than in MCT8 groups. Both MCT diets increased IRS-1 (612 phosphorylation and decreased S6K phosphorylation (240/244 but only MCT10 increased Akt phosphorylation (473. MCT8 supplementation increased synaptophysin, but not PSD-95, in contrast MCT10 had no effect on either synaptic marker. Expression of Ube3a, which controls synaptic stability, was increased by both MCT diets. Cortex transcription via qPCR showed that immediate early genes related to synaptic plasticity (arc, plk3, junb, egr2, nr4a1 were downregulated by both MCT diets while MCT8 additionally down-regulated fosb and egr1 but upregulated grin1 and gba2. These results demonstrate that treatment of 8- and 10-carbon length MCTs in aged rats have slight differential effects on synaptic stability, protein synthesis and behavior that may be independent of brain ketone levels.

  6. Anti-androgenic effects of bisphenol-A on spatial memory and synaptic plasticity of the hippocampus in mice.

    Science.gov (United States)

    Fang, Zhaoqing; Zhu, Qingjie; Gu, Ting; Shen, Xiuying; Yang, Yang; Liang, Yufeng; Zhang, Zigui; Xu, Xiaohong

    2017-07-01

    Bisphenol-A (BPA) is a common environmental endocrine disruptor. Our recent studies found that exposure to BPA in both adolescent and adulthood sex-specifically impaired spatial memory in male mice. In this study, 11-week-old gonadectomied (GDX) male mice daily received subcutaneous injections of testosterone propionate (TP, 0.5mg/kg), TP and BPA (0.4 and 4mg/kg), or vehicle for 45days. The results of Morris water maze task showed that exposure to BPA did not affect the spatial memory of GDX mice but impaired that of sham (4mg/kg/day) and TP-treated GDX mice (0.4mg/kg/day). In addition, BPA reduced the level of testosterone (T) in the serum and brain of sham and TP-treated GDX mice. Exposure to BPA decreased the synaptic density and had an adverse effect on the synaptic interface of the hippocampus in sham and TP-treated GDX mice. The results of western blot analysis further showed that BPA (4mg/kg) reduced the levels of synaptic proteins (synapsin I and PSD-95) and NMDA receptor subunit NR2B in sham and TP-treated GDX mice. BPA decreased the phosphorylation of ERK1/2 but increased the phosphorylation of p38 in sham and TP-treated GDX mice. These results suggest that impairment of spatial memory and adverse effects on synaptic remodeling of hippocampal neurons in males after long-term BPA exposure is related to the anti-androgen effect of BPA. These effects of BPA may be associated with downregulated synaptic proteins and NMDA receptor through inhib