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  1. Efavirenz Induces Neuronal Autophagy and Mitochondrial Alterations

    OpenAIRE

    Purnell, Phillip R; Fox, Howard S.

    2014-01-01

    Efavirenz (EFV) is a non-nucleoside reverse-transcriptase inhibitor in wide use for the treatment of human immunodeficiency virus infection. Although EFV is generally well tolerated, neuropsychiatric toxicity has been well documented. The toxic effects of EFV in hepatocytes and keratinocytes have been linked to mitochondrial perturbations and changes in autophagy. Here, we studied the effect of EFV on mitochondria and autophagy in neuronal cell lines and primary neurons. In SH-SY5Y cells, EFV...

  2. Efavirenz induces neuronal autophagy and mitochondrial alterations.

    Science.gov (United States)

    Purnell, Phillip R; Fox, Howard S

    2014-11-01

    Efavirenz (EFV) is a non-nucleoside reverse-transcriptase inhibitor in wide use for the treatment of human immunodeficiency virus infection. Although EFV is generally well tolerated, neuropsychiatric toxicity has been well documented. The toxic effects of EFV in hepatocytes and keratinocytes have been linked to mitochondrial perturbations and changes in autophagy. Here, we studied the effect of EFV on mitochondria and autophagy in neuronal cell lines and primary neurons. In SH-SY5Y cells, EFV induced a drop in ATP production, which coincided with increased autophagy, mitochondrial fragmentation, and mitochondrial depolarization. EFV-induced mitophagy was also detected by colocalization of mitochondria and autophagosomes and use of an outer mitochondrial membrane tandem fluorescent vector. Pharmacologic inhibition of autophagy with 3-methyladenine increased the cytotoxic effect of EFV, suggesting that autophagy promotes cell survival. EFV also reduces ATP production in primary neurons, induces autophagy, and changes mitochondrial morphology. Overall, EFV is able to acutely induce autophagy and mitochondrial changes in neurons. These changes may be involved in the mechanism leading to central nervous system toxicity observed in clinical EFV use. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  3. Biocytin: a neuronal tracer compatible with rapid decalcification procedures.

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    Wirsig-Wiechmann, C R

    1994-03-01

    The compatibility of neuronal tract-tracing and decalcification procedures was examined in salamander nasal chemosensory systems. Biocytin, but not horseradish peroxidase, retained its labeling capacity following rapid decalcification of the cranial bone. The combination of biocytin tract-tracing and decalcification procedures allows the visualization of labeled neurons and/or their projections within bony regions of intact specimens.

  4. Pseudorabies virus infection alters neuronal activity and connectivity in vitro.

    Directory of Open Access Journals (Sweden)

    Kelly M McCarthy

    2009-10-01

    Full Text Available Alpha-herpesviruses, including human herpes simplex virus 1 & 2, varicella zoster virus and the swine pseudorabies virus (PRV, infect the peripheral nervous system of their hosts. Symptoms of infection often include itching, numbness, or pain indicative of altered neurological function. To determine if there is an in vitro electrophysiological correlate to these characteristic in vivo symptoms, we infected cultured rat sympathetic neurons with well-characterized strains of PRV known to produce virulent or attenuated symptoms in animals. Whole-cell patch clamp recordings were made at various times after infection. By 8 hours of infection with virulent PRV, action potential (AP firing rates increased substantially and were accompanied by hyperpolarized resting membrane potentials and spikelet-like events. Coincident with the increase in AP firing rate, adjacent neurons exhibited coupled firing events, first with AP-spikelets and later with near identical resting membrane potentials and AP firing. Small fusion pores between adjacent cell bodies formed early after infection as demonstrated by transfer of the low molecular weight dye, Lucifer Yellow. Later, larger pores formed as demonstrated by transfer of high molecular weight Texas red-dextran conjugates between infected cells. Further evidence for viral-induced fusion pores was obtained by infecting neurons with a viral mutant defective for glycoprotein B, a component of the viral membrane fusion complex. These infected neurons were essentially identical to mock infected neurons: no increased AP firing, no spikelet-like events, and no electrical or dye transfer. Infection with PRV Bartha, an attenuated circuit-tracing strain delayed, but did not eliminate the increased neuronal activity and coupling events. We suggest that formation of fusion pores between infected neurons results in electrical coupling and elevated firing rates, and that these processes may contribute to the altered neural

  5. Dendritic and spinal alterations of neurons from Edinger-Westphal nucleus in Alzheimer's disease.

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    Mavroudis, Ioannis Asterios; Manani, Marina George; Petrides, Foivos; Petsoglou, Constantina; Njau, Samuel N; Costa, Vasiliki G; Baloyannis, Stavros J

    2014-01-01

    Alzheimer's disease (AD) is a heterogeneous neurodegenerative disorder, causing a progressive decline of intellectual faculties, impairment of behavior and social performance, and impairment of speech eloquence, associated with various neurological manifestations based on a variable neuropathological background. Edinger-Westphal nucleus is a selective target of Alzheimer pathology early in the course of the disease. We attempted to determine the morphological alterations of the dendrites and the dendritic spines in Edinger-Westphal nucleus of 7 cases that fulfilled the diagnostic criteria for Alzheimer's disease. For the histological study, we applied (a) routine neuropathological techniques and (b) rapid Golgi method. We proceeded to 3D neuronal reconstruction for the estimation of dendritic and spinal changes in Alzheimer's disease. The morphological and morphometric analysis revealed a substantial neuronal loss and synaptic alterations in Edinger-Westphal nucleus in all the cases of Alzheimer's disease. Distal dendritic branches are prominently affected. The neuronal loss and alteration of the spines in Edinger-Westphal nucleus in Alzheimer's disease may be related to the exaggerated pupillary reaction to cholinergic antagonists. Furthermore, the vulnerability of distal branches to Alzheimer's disease might be related to neuroplasticity impairment.

  6. Pituitary adenylate cyclase-activating polypeptide (PACAP) alters parasympathetic neuron gene expression in a time-dependent fashion.

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    Sumner, Adriane D; Margiotta, Joseph F

    2008-11-01

    Neuropeptides, including pituitary adenylate cyclase-activating polypeptide (PACAP), can influence diverse cellular processes over a broad temporal range. In ciliary ganglion (CG) neurons, for example, PACAP binding to high-affinity PAC1 receptors triggers transduction cascades that both rapidly modulate nicotinic receptors and synapses and support long-term survival. Since PACAP/PAC1 signaling recruits intracellular messengers and effectors that potently alter transcription, we examined its activation of the transcription factor CREB and then tested for changes in gene expression. PACAP/PAC1 signaling rapidly induced prolonged CREB activation in CG neurons by a phospholipase C -independent mechanism supported by Ca2+-influx, adenylate cyclase, and effectors, including protein kinase C (PKC) and possibly PKA. Since PACAP is abundant in the CG and released from depolarized presynaptic terminals, it is well suited to regulate gene expression relevant to neuronal and synaptic development. Gene array screens conducted using RNA from CG cultures grown with PACAP for 1/4, 24, or 96 h revealed a time-dependent pattern of > 600 regulated transcripts, including several encoding proteins implicated in synaptic function, neuronal survival, and development. The results underscore rapid, neuromodulatory, and long-term, neurotrophic consequences of PAC1 signaling in CG neurons and suggest that PACAP exerts such diverse influences by altering the expression of specific gene transcripts in a time-dependent fashion.

  7. The organizational and aromatization hypotheses apply to rapid, nonclassical hormone action: neonatal masculinization eliminates rapid estradiol action in female hippocampal neurons.

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    Meitzen, John; Grove, Danielle D; Mermelstein, Paul G

    2012-10-01

    Early exposure to the steroid sex hormone testosterone and its estrogen metabolite estradiol masculinize neural tissue during a developmental critical period. Many aspects of neuron anatomy and physiology are permanently altered, including later sensitivity to estradiol. Although it is well established that early hormone exposure alters neuronal responsiveness regarding classical estradiol actions (i.e. acting via nuclear estrogen receptors), it has not yet been determined whether it also alters neuronal processing of nonclassical estrogen receptor signaling, including the actions of membrane-associated estrogen receptors. Hence, we tested whether membrane estrogen receptor regulation of cAMP response element binding protein (CREB) phosphorylation observed in female (but not male) hippocampal pyramidal neurons is due to the lack of androgen and/or estrogen exposure in females during this critical period. Female rat neonates on postnatal d 0 and 1 were systemically injected with one of four compounds: vehicle, testosterone, the nonaromatizable androgen dihydrotestosterone, or estradiol. On postnatal d 2, primary hippocampal neuron cultures were generated from these animals. After 8-9 d in culture, we assessed whether estradiol affected CREB phosphorylation. Neurons from female neonates exposed to testosterone lacked estradiol signaling to CREB. In contrast, dihydrotestosterone injections of female neonates did not disrupt estradiol regulation of CREB. Estradiol injections of female neonates, however, eliminated estradiol signaling to CREB. These findings indicate that testosterone aromatization to estradiol leads to a masculinization/defeminization process whereby hippocampal neurons fail to exhibit rapid estradiol signaling to CREB. Broadly, these findings extend the organizational and aromatization hypotheses to rapid, nonclassical hormone action.

  8. Rapid sensing of l-leucine by human and murine hypothalamic neurons: Neurochemical and mechanistic insights.

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    Heeley, Nicholas; Kirwan, Peter; Darwish, Tamana; Arnaud, Marion; Evans, Mark L; Merkle, Florian T; Reimann, Frank; Gribble, Fiona M; Blouet, Clemence

    2018-02-07

    Dietary proteins are sensed by hypothalamic neurons and strongly influence multiple aspects of metabolic health, including appetite, weight gain, and adiposity. However, little is known about the mechanisms by which hypothalamic neural circuits controlling behavior and metabolism sense protein availability. The aim of this study is to characterize how neurons from the mediobasal hypothalamus respond to a signal of protein availability: the amino acid l-leucine. We used primary cultures of post-weaning murine mediobasal hypothalamic neurons, hypothalamic neurons derived from human induced pluripotent stem cells, and calcium imaging to characterize rapid neuronal responses to physiological changes in extracellular l-Leucine concentration. A neurochemically diverse subset of both mouse and human hypothalamic neurons responded rapidly to l-leucine. Consistent with l-leucine's anorexigenic role, we found that 25% of mouse MBH POMC neurons were activated by l-leucine. 10% of MBH NPY neurons were inhibited by l-leucine, and leucine rapidly reduced AGRP secretion, providing a mechanism for the rapid leucine-induced inhibition of foraging behavior in rodents. Surprisingly, none of the candidate mechanisms previously implicated in hypothalamic leucine sensing (K ATP channels, mTORC1 signaling, amino-acid decarboxylation) were involved in the acute activity changes produced by l-leucine. Instead, our data indicate that leucine-induced neuronal activation involves a plasma membrane Ca 2+ channel, whereas leucine-induced neuronal inhibition is mediated by inhibition of a store-operated Ca 2+ current. A subset of neurons in the mediobasal hypothalamus rapidly respond to physiological changes in extracellular leucine concentration. Leucine can produce both increases and decreases in neuronal Ca 2+ concentrations in a neurochemically-diverse group of neurons, including some POMC and NPY/AGRP neurons. Our data reveal that leucine can signal through novel mechanisms to rapidly

  9. Methamphetamine induces a rapid increase of intracellular Ca(++) levels in neurons overexpressing GCaMP5.

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    Yu, Seong-Jin; Wu, Kou-Jen; Bae, Eun K; Hsu, Man-Jung; Richie, Christopher T; Harvey, Brandon K; Wang, Yun

    2016-03-01

    In this study, methamphetamine (Meth)- and glutamate (Glu)-mediated intracellular Ca(++) (Ca(++) i) signals were examined in real time in primary cortical neurons overexpressing an intracellular Ca(++) probe, GCaMP5, by adeno-associated viral (AAV) serotype 1. Binding of Ca(++) to GCaMP increased green fluorescence intensity in cells. Both Meth and Glu induced a rapid increase in Ca(++) i, which was blocked by MK801, suggesting that Meth enhanced Ca(++) i through Glu receptor in neurons. The Meth-mediated Ca(++) signal was also blocked by Mg(++) , low Ca(++) or the L-type Ca(++) channel inhibitor nifedipine. The ryanodine receptor inhibitor dantrolene did not alter the initial Ca(++) influx but partially reduced the peak of Ca(++) i. These data suggest that Meth enhanced Ca(++) influx through membrane Ca(++) channels, which then triggered the release of Ca(++) from the endoplasmic reticulum in the cytosol. AAV-GCaMP5 was also injected to the parietal cortex of adult rats. Administration of Meth enhanced fluorescence in the ipsilateral cortex. Using immunohistochemistry, Meth-induced green fluorescence was found in the NeuN-containing cells in the cortex, suggesting that Meth increased Ca(++) in neurons in vivo. In conclusion, we have used in vitro and in vivo techniques to demonstrate a rapid increase of Ca(++) i by Meth in cortical neurons through overexpression of GCaMP5. As Meth induces behavioral responses and neurotoxicity through Ca(++) i, modulation of Ca(++) i may be useful to reduce Meth-related reactions. © 2014 Society for the Study of Addiction.

  10. DARPP-32 interaction with adducin may mediate rapid environmental effects on striatal neurons

    Science.gov (United States)

    Engmann, Olivia; Giralt, Albert; Gervasi, Nicolas; Marion-Poll, Lucile; Gasmi, Laila; Filhol, Odile; Picciotto, Marina R.; Gilligan, Diana; Greengard, Paul; Nairn, Angus C.; Hervé, Denis; Girault, Jean-Antoine

    2015-01-01

    Environmental enrichment has multiple effects on behaviour, including modification of responses to psychostimulant drugs mediated by striatal neurons. However, the underlying molecular and cellular mechanisms are not known. Here we show that DARPP-32, a hub signalling protein in striatal neurons, interacts with adducins, which are cytoskeletal proteins that cap actin filaments' fast-growing ends and regulate synaptic stability. DARPP-32 binds to adducin MARCKS domain and this interaction is modulated by DARPP-32 Ser97 phosphorylation. Phospho-Thr75-DARPP-32 facilitates β-adducin Ser713 phosphorylation through inhibition of a cAMP-dependent protein kinase/phosphatase-2A cascade. Caffeine or 24-h exposure to a novel enriched environment increases adducin phosphorylation in WT, but not T75A mutant mice. This cascade is implicated in the effects of brief exposure to novel enriched environment on dendritic spines in nucleus accumbens and cocaine locomotor response. Our results suggest a molecular pathway by which environmental changes may rapidly alter responsiveness of striatal neurons involved in the reward system. PMID:26639316

  11. Glutamate and GABA as rapid effectors of hypothalamic peptidergic neurons

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    Cornelia eSchöne

    2012-11-01

    Full Text Available Vital hypothalamic neurons regulating hunger, wakefulness, reward-seeking, and body weight are often defined by unique expression of hypothalamus-specific neuropeptides. Gene-ablation studies show that some of these peptides, notably orexin/hypocretin (hcrt/orx, are themselves critical for stable states of consciousness and metabolic health. However, neuron-ablation studies often reveal more severe phenotypes, suggesting key roles for co-expressed transmitters. Indeed, most hypothalamic neurons, including hcrt/orx cells, contain fast transmitters glutamate and GABA, as well as several neuropeptides. What are the roles and relations between different transmitters expressed by the same neuron? Here, we consider signaling codes for releasing different transmitters in relation to transmitter and receptor diversity in behaviorally-defined, widely-projecting peptidergic neurons, such as hcrt/orx cells. We then discuss latest optogenetic studies of endogenous transmitter release from defined sets of axons in situ, which suggest that recently-characterized vital peptidergic neurons (e.g. hcrt/orx, proopiomelanocortin , and agouti-related peptide cells, as well as classical modulatory neurons (e.g. dopamine and acetylcholine cells, all use fast transmitters to control their postsynaptic targets. These optogenetic insights are complemented by recent observations of behavioral deficiencies caused by genetic ablation of fast transmission from specific neuropeptidergic and aminergic neurons. Powerful and fast (millisecond-scale GABAergic and glutamatergic signaling from neurons previously considered to be primarily modulatory raises new questions about the roles of slower co-transmitters they co-express.

  12. Diet rapidly and reproducibly alters the human gut microbiome

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    David, Lawrence A.; Maurice, Corinne F.; Carmody, Rachel N.; Gootenberg, David B.; Button, Julie E.; Wolfe, Benjamin E.; Ling, Alisha V.; Devlin, A. Sloan; Varma, Yug; Fischbach, Michael A.; Biddinger, Sudha B.; Dutton, Rachel J.; Turnbaugh, Peter J.

    2013-01-01

    Long-term diet influences the structure and activity of the trillions of microorganisms residing in the human gut1–5, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here, we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila, and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale, and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals2, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi, and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids, and the outgrowth of microorganisms capable of triggering inflammatory bowel disease6. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles. PMID:24336217

  13. Specific alterations in levels of mannose 6-phosphorylated glycoproteins in different neuronal ceroid lipofuscinoses.

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    Sleat, D E; Sohar, I; Pullarkat, P S; Lobel, P; Pullarkat, R K

    1998-01-01

    Mannose 6-phosphate (Man-6-P) is a carbohydrate modification that is generated on newly synthesized lysosomal proteins. This modification is specifically recognized by two Man-6-P receptors that direct the vesicular transport of the lysosomal enzymes from the Golgi to a prelysosomal compartment. The Man-6-P is rapidly removed in the lysosome of most cell types; however, in neurons the Man-6-P modification persists. In this study we have examined the spectrum of Man-6-P-containing glycoproteins in brain specimens from patients with different neuronal ceroid lipofuscinoses (NCLs), which are progressive neurodegenerative disorders with established links to defects in lysosomal catabolism. We find characteristic alterations in the Man-6-P glycoproteins in specimens from late-infantile (LINCL), juvenile (JNCL) and adult (ANCL) patients. Man-6-P glycoproteins in LINCL patients were similar to controls, with the exception that the band corresponding to CLN2, a recently identified lysosomal enzyme whose deficiency results in this disease, was absent. In an ANCL patient, two Man-6-P glycoproteins were elevated in comparison with normal controls, suggesting that this disease also results from a perturbation in lysosomal hydrolysis. In JNCL, total levels of Man-6-P glycoproteins were 7-fold those of controls. In general this was reflected by increased lysosomal enzyme activities in JNCL but three Man-6-P glycoproteins were elevated to an even greater degree. These are CLN2 and the unidentified proteins that are also highly elevated in the ANCL. PMID:9729460

  14. Selected statins produce rapid spinal motor neuron loss in vitro

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    Murinson Beth B

    2012-06-01

    Full Text Available Abstract Background Hmg-CoA reductase inhibitors (statins are widely used to prevent disease associated with vascular disease and hyperlipidemia. Although side effects are uncommon, clinical observations suggest statin exposure may exacerbate neuromuscular diseases, including peripheral neuropathy and amyotrophic lateral sclerosis. Although some have postulated class-effects, prior studies of hepatocytes and myocytes indicate that the statins may exhibit differential effects. Studies of neuronal cells have been limited. Methods We examined the effects of statins on cultured neurons and Schwann cells. Cultured spinal motor neurons were grown on transwell inserts and assessed for viability using immunochemical staining for SMI-32. Cultured cortical neurons and Schwann cells were assessed using dynamic viability markers. Results 7 days of exposure to fluvastatin depleted spinal motor neurons in a dose-dependent manner with a KD of  Conclusions It is known from pharmacokinetic studies that daily treatment of young adults with fluvastatin can produce serum levels in the single micromolar range. We conclude that specific mechanisms may explain neuromuscular disease worsening with statins and further study is needed.

  15. Mechanism of the Rapid Effect of 17β -Estradiol on Medial Amygdala Neurons

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    Nabekura, Junichi; Oomura, Yutaka; Minami, Taketsugu; Mizuno, Yuji; Fukuda, Atsuo

    1986-07-01

    The mechanism by which sex steroids rapidly modulate the excitability of neurons was investigated by intracellular recording of neurons in rat medial amygdala brain slices. Brief hyperpolarization and increased potassium conductance were produced by 17β - estradiol. This effect persisted after elimination of synaptic input and after suppression of protein synthesis. Thus, 17β -estradiol directly changes the ionic conductance of the postsynaptic membrane of medial amygdala neurons. In addition, a greater proportion of the neurons from females than from males responded to 17β -estradiol.

  16. Environmental enrichment alters neuronal processing in the nucleus accumbens core during appetitive conditioning.

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    Wood, David A; Rebec, George V

    2009-03-09

    Although the core region of the nucleus accumbens (NAcc) has been implicated in motor control and the acquisition of appetitive learning, these processes are altered by environmental experience. To assess how environment influences neuronal processing in NAcc core, we recorded single-unit activity during acquisition of an appetitive learning task in which rats reared in an environmentally enriched condition (EC) learned the operant response (nosepoke into a lit hole) for sucrose reinforcement faster than rats reared in an isolated condition (IC). In the first training session, even before the emergence of learning differences, core neurons were more likely to respond (increase or decrease activity) during the operant and consummatory responses in EC than IC rats. By the third training session, when learning differences emerged, EC neurons continued to be more responsive than IC neurons, but in very different ways: the response shifted to the cues that signaled trial onset (1900 Hz tone and green LED) and reward availability (4500 Hz tone and yellow LED). Cue-related responding, moreover, was dominated by neuronal excitations. In contrast, post-acquisition recordings revealed no EC-IC differences. Collectively, these results suggest that core neurons are initially more responsive to discrete, goal-directed movements in EC rats, but as learning materializes, the neuronal response shifts to the cues that predict these movements. Thus, environmental experience alters core neuronal processing of both motor- and sensory-related events but at different stages over the course of learning.

  17. Altered Chloride Homeostasis Decreases the Action Potential Threshold and Increases Hyperexcitability in Hippocampal Neurons.

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    Sørensen, Andreas T; Ledri, Marco; Melis, Miriam; Nikitidou Ledri, Litsa; Andersson, My; Kokaia, Merab

    2017-01-01

    Chloride ions play an important role in controlling excitability of principal neurons in the central nervous system. When neurotransmitter GABA is released from inhibitory interneurons, activated GABA type A (GABA A ) receptors on principal neurons become permeable to chloride. Typically, chloride flows through activated GABA A receptors into the neurons causing hyperpolarization or shunting inhibition, and in turn inhibits action potential (AP) generation. However, in situations when intracellular chloride concentration is increased, chloride ions can flow in opposite direction, depolarize neurons, and promote AP generation. It is generally recognized that altered chloride homeostasis per se has no effect on the AP threshold. Here, we demonstrate that chloride overload of mouse principal CA3 pyramidal neurons not only makes these cells more excitable through GABA A receptor activation but also lowers the AP threshold, further aggravating excitability. This phenomenon has not been described in principal neurons and adds to our understanding of mechanisms regulating neuronal and network excitability, particularly in developing brain and during pathological situations with altered chloride homeostasis. This finding further broadens the spectrum of neuronal plasticity regulated by ionic compositions across the cellular membrane.

  18. Chronic alterations in monoaminergic cells in the locus coeruleus in orexin neuron-ablated narcoleptic mice.

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    Natsuko Tsujino

    Full Text Available Narcolepsy patients often suffer from insomnia in addition to excessive daytime sleepiness. Narcoleptic animals also show behavioral instability characterized by frequent transitions between all vigilance states, exhibiting very short bouts of NREM sleep as well as wakefulness. The instability of wakefulness states in narcolepsy is thought to be due to deficiency of orexins, neuropeptides produced in the lateral hypothalamic neurons, which play a highly important role in maintaining wakefulness. However, the mechanism responsible for sleep instability in this disorder remains to be elucidated. Because firing of orexin neurons ceases during sleep in healthy animals, deficiency of orexins does not explain the abnormality of sleep. We hypothesized that chronic compensatory changes in the neurophysiologica activity of the locus coeruleus (LC and dorsal raphe (DR nucleus in response to the progressive loss of endogenous orexin tone underlie the pathological regulation of sleep/wake states. To evaluate this hypothesis, we examined firing patterns of serotonergic (5-HT neurons and noradrenergic (NA neurons in the brain stem, two important neuronal populations in the regulation of sleep/wakefulness states. We recorded single-unit activities of 5-HT neurons and NA neurons in the DR nucleus and LC of orexin neuron-ablated narcoleptic mice. We found that while the firing pattern of 5-HT neurons in narcoleptic mice was similar to that in wildtype mice, that of NA neurons was significantly different from that in wildtype mice. In narcoleptic mice, NA neurons showed a higher firing frequency during both wakefulness and NREM sleep as compared with wildtype mice. In vitro patch-clamp study of NA neurons of narcoleptic mice suggested a functional decrease of GABAergic input to these neurons. These alterations might play roles in the sleep abnormality in narcolepsy.

  19. Hypothyroidism and its rapid correction alter cardiac remodeling.

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    Georges Hajje

    Full Text Available The cardiovascular effects of mild and overt thyroid disease include a vast array of pathological changes. As well, thyroid replacement therapy has been suggested for preserving cardiac function. However, the influence of thyroid hormones on cardiac remodeling has not been thoroughly investigated at the molecular and cellular levels. The purpose of this paper is to study the effect of hypothyroidism and thyroid replacement therapy on cardiac alterations. Thirty Wistar rats were divided into 2 groups: a control (n = 10 group and a group treated with 6-propyl-2-thiouracil (PTU (n = 20 to induce hypothyroidism. Ten of the 20 rats in the PTU group were then treated with L-thyroxine to quickly re-establish euthyroidism. The serum levels of inflammatory markers, such as C-reactive protein (CRP, tumor necrosis factor alpha (TNF-α, interleukin 6 (IL6 and pro-fibrotic transforming growth factor beta 1 (TGF-β1, were significantly increased in hypothyroid rats; elevations in cardiac stress markers, brain natriuretic peptide (BNP and cardiac troponin T (cTnT were also noted. The expressions of cardiac remodeling genes were induced in hypothyroid rats in parallel with the development of fibrosis, and a decline in cardiac function with chamber dilation was measured by echocardiography. Rapidly reversing the hypothyroidism and restoring the euthyroid state improved cardiac function with a decrease in the levels of cardiac remodeling markers. However, this change further increased the levels of inflammatory and fibrotic markers in the plasma and heart and led to myocardial cellular infiltration. In conclusion, we showed that hypothyroidism is related to cardiac function decline, fibrosis and inflammation; most importantly, the rapid correction of hypothyroidism led to cardiac injuries. Our results might offer new insights for the management of hypothyroidism-induced heart disease.

  20. Hypothyroidism and its rapid correction alter cardiac remodeling.

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    Hajje, Georges; Saliba, Youakim; Itani, Tarek; Moubarak, Majed; Aftimos, Georges; Farès, Nassim

    2014-01-01

    The cardiovascular effects of mild and overt thyroid disease include a vast array of pathological changes. As well, thyroid replacement therapy has been suggested for preserving cardiac function. However, the influence of thyroid hormones on cardiac remodeling has not been thoroughly investigated at the molecular and cellular levels. The purpose of this paper is to study the effect of hypothyroidism and thyroid replacement therapy on cardiac alterations. Thirty Wistar rats were divided into 2 groups: a control (n = 10) group and a group treated with 6-propyl-2-thiouracil (PTU) (n = 20) to induce hypothyroidism. Ten of the 20 rats in the PTU group were then treated with L-thyroxine to quickly re-establish euthyroidism. The serum levels of inflammatory markers, such as C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL6) and pro-fibrotic transforming growth factor beta 1 (TGF-β1), were significantly increased in hypothyroid rats; elevations in cardiac stress markers, brain natriuretic peptide (BNP) and cardiac troponin T (cTnT) were also noted. The expressions of cardiac remodeling genes were induced in hypothyroid rats in parallel with the development of fibrosis, and a decline in cardiac function with chamber dilation was measured by echocardiography. Rapidly reversing the hypothyroidism and restoring the euthyroid state improved cardiac function with a decrease in the levels of cardiac remodeling markers. However, this change further increased the levels of inflammatory and fibrotic markers in the plasma and heart and led to myocardial cellular infiltration. In conclusion, we showed that hypothyroidism is related to cardiac function decline, fibrosis and inflammation; most importantly, the rapid correction of hypothyroidism led to cardiac injuries. Our results might offer new insights for the management of hypothyroidism-induced heart disease.

  1. Synaptic vesicle morphology and recycling are altered in myenteric neurons of mice lacking dystrophin (mdx mice).

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    Vannucchi, Maria Giuliana; Corsani, Letizia; Faussone-Pellegrini, Maria-Simonetta

    2003-11-01

    Several dystrophin isoforms are known. The full-length isoform is present in striated and smooth muscles and neurons and its lack causes Duchenne Muscular Dystrophy, a progressive myopathy accompanied by mild cognitive deficits and gastrointestinal dismotility. An ultrastructural study was undertaken in the colon of mice lacking full-length dystrophin and maintaining shorter isoforms (mdx mice) to ascertain whether myenteric neurons have an altered morphology. Results showed a significant increase in the size of synaptic vesicle and in the number of recycling vesicles. An enlargement of endoplasmic reticulum cisternae in a subpopulation of neurons was also seen. Immunohistochemistry confirmed that the shorter isoforms were expressed in mdx mice myenteric neurons. These findings indicate the presence of a neuropathy at the myenteric plexus which might justify the defective neuronal control of gastrointestinal motility reported for these animals and which might be correlated with full-length dystrophin loss, since the shorter isoforms are present. Copyright 2003 Wiley-Liss, Inc.

  2. Acute Lesioning and Rapid Repair of Hypothalamic Neurons outside the Blood-Brain Barrier

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    Ernie Yulyaningsih

    2017-06-01

    Full Text Available Neurons expressing agouti-related protein (AgRP are essential for feeding. The majority of these neurons are located outside the blood-brain barrier (BBB, allowing them to directly sense circulating metabolic factors. Here, we show that, in adult mice, AgRP neurons outside the BBB (AgRPOBBB were rapidly ablated by peripheral administration of monosodium glutamate (MSG, whereas AgRP neurons inside the BBB and most proopiomelanocortin (POMC neurons were spared. MSG treatment induced proliferation of tanycytes, the putative hypothalamic neural progenitor cells, but the newly proliferated tanycytes did not become neurons. Intriguingly, AgRPOBBB neuronal number increased within a week after MSG treatment, and newly emerging AgRP neurons were derived from post-mitotic cells, including some from the Pomc-expressing cell lineage. Our study reveals that the lack of protection by the BBB renders AgRPOBBB vulnerable to lesioning by circulating toxins but that the rapid re-emergence of AgRPOBBB is part of a reparative process to maintain energy balance.

  3. Rapid method for culturing embryonic neuron-glial cell cocultures

    DEFF Research Database (Denmark)

    Svenningsen, Åsa Fex; Shan, Wei-Song; Colman, David R

    2003-01-01

    to cultures first treated with antimitotic agents. It also ensures that all the cells present in vivo will be present in the culture. Myelination commences after approximately 2 weeks in culture for dissociated DRG and 3-4 weeks in cerebellar cultures. In enteric cultures, glial wrapping of the enteric...... neurons is seen after 3 weeks (2 weeks in ascorbic acid), suggesting that basal lamina production is important even for glial ensheathment in the enteric nervous system. No overgrowth of fibroblasts or other nonneuronal cells was noted in any cultures, and myelination of the peripheral nervous system...

  4. MAPT Genetic Variation and Neuronal Maturity Alter Isoform Expression Affecting Axonal Transport in iPSC-Derived Dopamine Neurons.

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    Beevers, Joel E; Lai, Mang Ching; Collins, Emma; Booth, Heather D E; Zambon, Federico; Parkkinen, Laura; Vowles, Jane; Cowley, Sally A; Wade-Martins, Richard; Caffrey, Tara M

    2017-08-08

    The H1 haplotype of the microtubule-associated protein tau (MAPT) locus is genetically associated with neurodegenerative diseases, including Parkinson's disease (PD), and affects gene expression and splicing. However, the functional impact on neurons of such expression differences has yet to be fully elucidated. Here, we employ extended maturation phases during differentiation of induced pluripotent stem cells (iPSCs) into mature dopaminergic neuronal cultures to obtain cultures expressing all six adult tau protein isoforms. After 6 months of maturation, levels of exon 3+ and exon 10+ transcripts approach those of adult brain. Mature dopaminergic neuronal cultures display haplotype differences in expression, with H1 expressing 22% higher levels of MAPT transcripts than H2 and H2 expressing 2-fold greater exon 3+ transcripts than H1. Furthermore, knocking down adult tau protein variants alters axonal transport velocities in mature iPSC-derived dopaminergic neuronal cultures. This work links haplotype-specific MAPT expression with a biologically functional outcome relevant for PD. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  5. MAPT Genetic Variation and Neuronal Maturity Alter Isoform Expression Affecting Axonal Transport in iPSC-Derived Dopamine Neurons

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    Joel E. Beevers

    2017-08-01

    Full Text Available The H1 haplotype of the microtubule-associated protein tau (MAPT locus is genetically associated with neurodegenerative diseases, including Parkinson's disease (PD, and affects gene expression and splicing. However, the functional impact on neurons of such expression differences has yet to be fully elucidated. Here, we employ extended maturation phases during differentiation of induced pluripotent stem cells (iPSCs into mature dopaminergic neuronal cultures to obtain cultures expressing all six adult tau protein isoforms. After 6 months of maturation, levels of exon 3+ and exon 10+ transcripts approach those of adult brain. Mature dopaminergic neuronal cultures display haplotype differences in expression, with H1 expressing 22% higher levels of MAPT transcripts than H2 and H2 expressing 2-fold greater exon 3+ transcripts than H1. Furthermore, knocking down adult tau protein variants alters axonal transport velocities in mature iPSC-derived dopaminergic neuronal cultures. This work links haplotype-specific MAPT expression with a biologically functional outcome relevant for PD.

  6. Systematic Three-Dimensional Coculture Rapidly Recapitulates Interactions between Human Neurons and Astrocytes

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    Robert Krencik

    2017-12-01

    Full Text Available Summary: Human astrocytes network with neurons in dynamic ways that are still poorly defined. Our ability to model this relationship is hampered by the lack of relevant and convenient tools to recapitulate this complex interaction. To address this barrier, we have devised efficient coculture systems utilizing 3D organoid-like spheres, termed asteroids, containing pre-differentiated human pluripotent stem cell (hPSC-derived astrocytes (hAstros combined with neurons generated from hPSC-derived neural stem cells (hNeurons or directly induced via Neurogenin 2 overexpression (iNeurons. Our systematic methods rapidly produce structurally complex hAstros and synapses in high-density coculture with iNeurons in precise numbers, allowing for improved studies of neural circuit function, disease modeling, and drug screening. We conclude that these bioengineered neural circuit model systems are reliable and scalable tools to accurately study aspects of human astrocyte-neuron functional properties while being easily accessible for cell-type-specific manipulations and observations. : In this article, Krencik and colleagues show that high-density cocultures of pre-differentiated human astrocytes with induced neurons, from pluripotent stem cells, elicit mature characteristics by 3–5 weeks. This provides a faster and more defined alternative method to organoid cultures for investigating human neural circuit function. Keywords: human pluripotent stem cells, neurons, astrocytes, synapses, coculture, three-dimensional spheres, organoids, disease modeling

  7. Degeneration of dopaminergic neurons due to metabolic alterations and Parkinson’s disease

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    Juhyun eSong

    2016-03-01

    Full Text Available The rates of metabolic diseases, such as type 2 diabetes mellitus (T2DM, obesity, and cardiovascular disease, markedly increase with age. In recent years, studies have reported an association between metabolic changes and various pathophysiological mechanisms in the central nervous system (CNS in patients with metabolic diseases. Oxidative stress and hyperglycemia in metabolic diseases lead to adverse neurophysiological phenomena, including neuronal loss, synaptic dysfunction, and improper insulin signaling, resulting in Parkinson’s disease (PD. In addition, several lines of evidence suggest that alterations of CNS environments by metabolic changes influence the dopamine neuronal loss, eventually affecting the pathogenesis of PD. Thus, we reviewed recent findings relating to degeneration of dopaminergic neurons during metabolic diseases. We highlight the fact that using a metabolic approach to manipulate degeneration of dopaminergic neurons can serve as a therapeutic strategy to attenuate pathology of PD.

  8. Rapid metabolism of exogenous angiotensin II by catecholaminergic neuronal cells in culture media.

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    Basu, Urmi; Seravalli, Javier; Madayiputhiya, Nandakumar; Adamec, Jiri; Case, Adam J; Zimmerman, Matthew C

    2015-02-01

    Angiotensin II (AngII) acts on central neurons to increase neuronal firing and induce sympathoexcitation, which contribute to the pathogenesis of cardiovascular diseases including hypertension and heart failure. Numerous studies have examined the precise AngII-induced intraneuronal signaling mechanism in an attempt to identify new therapeutic targets for these diseases. Considering the technical challenges in studying specific intraneuronal signaling pathways in vivo, especially in the cardiovascular control brain regions, most studies have relied on neuronal cell culture models. However, there are numerous limitations in using cell culture models to study AngII intraneuronal signaling, including the lack of evidence indicating the stability of AngII in culture media. Herein, we tested the hypothesis that exogenous AngII is rapidly metabolized in neuronal cell culture media. Using liquid chromatography-tandem mass spectrometry, we measured levels of AngII and its metabolites, Ang III, Ang IV, and Ang-1-7, in neuronal cell culture media after administration of exogenous AngII (100 nmol/L) to a neuronal cell culture model (CATH.a neurons). AngII levels rapidly declined in the media, returning to near baseline levels within 3 h of administration. Additionally, levels of Ang III and Ang-1-7 acutely increased, while levels of Ang IV remained unchanged. Replenishing the media with exogenous AngII every 3 h for 24 h resulted in a consistent and significant increase in AngII levels for the duration of the treatment period. These data indicate that AngII is rapidly metabolized in neuronal cell culture media, and replenishing the media at least every 3 h is needed to sustain chronically elevated levels. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  9. Diabetic polyneuropathy, sensory neurons, nuclear structure and spliceosome alterations: a role for CWC22.

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    Kobayashi, Masaki; Chandrasekhar, Ambika; Cheng, Chu; Martinez, Jose A; Ng, Hilarie; de la Hoz, Cristiane; Zochodne, Douglas W

    2017-03-01

    Unique deficits in the function of adult sensory neurons as part of their early neurodegeneration might account for progressive polyneuropathy during chronic diabetes mellitus. Here, we provide structural and functional evidence for aberrant pre-mRNA splicing in a chronic type 1 model of experimental diabetic polyneuropathy (DPN). Cajal bodies (CBs), unique nuclear substructures involved in RNA splicing, increased in number in diabetic sensory neurons, but their expected colocalization with survival motor neuron (SMN) proteins was reduced - a mislocalization described in motor neurons of spinal muscular atrophy. Small nuclear ribonucleoprotein particles (snRNPs), also participants in the spliceosome, had abnormal multiple nuclear foci unassociated with CBs, and their associated snRNAs were reduced. CWC22, a key spliceosome protein, was aberrantly upregulated in diabetic dorsal root ganglia (DRG), and impaired neuronal function. CWC22 attenuated sensory neuron plasticity, with knockdown in vitro enhancing their neurite outgrowth. Further, axonal delivery of CWC22 siRNA unilaterally to locally knock down the aberrant protein in diabetic nerves improved aspects of sensory function in diabetic mice. Collectively, our findings identify subtle but significant alterations in spliceosome structure and function, including dysregulated CBs and CWC22 overexpression, in diabetic sensory neurons that offer new ideas regarding diabetic sensory neurodegeneration in polyneuropathy. © 2017. Published by The Company of Biologists Ltd.

  10. Diabetic polyneuropathy, sensory neurons, nuclear structure and spliceosome alterations: a role for CWC22

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    Masaki Kobayashi

    2017-03-01

    Full Text Available Unique deficits in the function of adult sensory neurons as part of their early neurodegeneration might account for progressive polyneuropathy during chronic diabetes mellitus. Here, we provide structural and functional evidence for aberrant pre-mRNA splicing in a chronic type 1 model of experimental diabetic polyneuropathy (DPN. Cajal bodies (CBs, unique nuclear substructures involved in RNA splicing, increased in number in diabetic sensory neurons, but their expected colocalization with survival motor neuron (SMN proteins was reduced – a mislocalization described in motor neurons of spinal muscular atrophy. Small nuclear ribonucleoprotein particles (snRNPs, also participants in the spliceosome, had abnormal multiple nuclear foci unassociated with CBs, and their associated snRNAs were reduced. CWC22, a key spliceosome protein, was aberrantly upregulated in diabetic dorsal root ganglia (DRG, and impaired neuronal function. CWC22 attenuated sensory neuron plasticity, with knockdown in vitro enhancing their neurite outgrowth. Further, axonal delivery of CWC22 siRNA unilaterally to locally knock down the aberrant protein in diabetic nerves improved aspects of sensory function in diabetic mice. Collectively, our findings identify subtle but significant alterations in spliceosome structure and function, including dysregulated CBs and CWC22 overexpression, in diabetic sensory neurons that offer new ideas regarding diabetic sensory neurodegeneration in polyneuropathy.

  11. Severely impaired learning and altered neuronal morphology in mice lacking NMDA receptors in medium spiny neurons.

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    Lisa R Beutler

    Full Text Available The striatum is composed predominantly of medium spiny neurons (MSNs that integrate excitatory, glutamatergic inputs from the cortex and thalamus, and modulatory dopaminergic inputs from the ventral midbrain to influence behavior. Glutamatergic activation of AMPA, NMDA, and metabotropic receptors on MSNs is important for striatal development and function, but the roles of each of these receptor classes remain incompletely understood. Signaling through NMDA-type glutamate receptors (NMDARs in the striatum has been implicated in various motor and appetitive learning paradigms. In addition, signaling through NMDARs influences neuronal morphology, which could underlie their role in mediating learned behaviors. To study the role of NMDARs on MSNs in learning and in morphological development, we generated mice lacking the essential NR1 subunit, encoded by the Grin1 gene, selectively in MSNs. Although these knockout mice appear normal and display normal 24-hour locomotion, they have severe deficits in motor learning, operant conditioning and active avoidance. In addition, the MSNs from these knockout mice have smaller cell bodies and decreased dendritic length compared to littermate controls. We conclude that NMDAR signaling in MSNs is critical for normal MSN morphology and many forms of learning.

  12. Alterations in Neuronal Activity in Basal Ganglia-Thalamocortical Circuits in the Parkinsonian State

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    Adriana eGalvan

    2015-02-01

    Full Text Available In patients with Parkinson’s disease and in animal models of this disorder, neurons in the basal ganglia and related regions in thalamus and cortex show changes that can be recorded by using electrophysiologic single-cell recording techniques, including altered firing rates and patterns, pathologic oscillatory activity and increased inter-neuronal synchronization. In addition, changes in synaptic potentials or in the joint spiking activities of populations of neurons can be monitored as alterations in local field potentials, electroencephalograms or electrocorticograms. Most of the mentioned electrophysiologic changes are probably related to the degeneration of diencephalic dopaminergic neurons, leading to dopamine loss in the striatum and other basal ganglia nuclei, although degeneration of non-dopaminergic cell groups may also have a role. The altered electrical activity of the basal ganglia and associated nuclei may contribute to some of the motor signs of the disease. We here review the current knowledge of the electrophysiologic changes at the single cell level, the level of local populations of neural elements, and the level of the entire basal ganglia-thalamocortical network in parkinsonism, and discuss the possible use of this information to optimize treatment approaches to Parkinson’s disease, such as deep brain stimulation therapy.

  13. Rapid generation of mitochondrial superoxide induces mitochondrion-dependent but caspase-independent cell death in hippocampal neuronal cells that morphologically resembles necroptosis

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    Fukui, Masayuki; Choi, Hye Joung; Zhu, Bao Ting, E-mail: BTZhu@kumc.edu

    2012-07-15

    Studies in recent years have revealed that excess mitochondrial superoxide production is an important etiological factor in neurodegenerative diseases, resulting from oxidative modifications of cellular lipids, proteins, and nucleic acids. Hence, it is important to understand the mechanism by which mitochondrial oxidative stress causes neuronal death. In this study, the immortalized mouse hippocampal neuronal cells (HT22) in culture were used as a model and they were exposed to menadione (also known as vitamin K{sub 3}) to increase intracellular superoxide production. We found that menadione causes preferential accumulation of superoxide in the mitochondria of these cells, along with the rapid development of mitochondrial dysfunction and cellular ATP depletion. Neuronal death induced by menadione is independent of the activation of the MAPK signaling pathways and caspases. The lack of caspase activation is due to the rapid depletion of cellular ATP. It was observed that two ATP-independent mitochondrial nucleases, namely, AIF and Endo G, are released following menadione exposure. Silencing of their expression using specific siRNAs results in transient suppression (for ∼ 12 h) of mitochondrial superoxide-induced neuronal death. While suppression of the mitochondrial superoxide dismutase expression markedly sensitizes neuronal cells to mitochondrial superoxide-induced cytotoxicity, its over-expression confers strong protection. Collectively, these findings showed that many of the observed features associated with mitochondrial superoxide-induced cell death, including caspase independency, rapid depletion of ATP level, mitochondrial release of AIF and Endo G, and mitochondrial swelling, are distinctly different from those of apoptosis; instead they resemble some of the known features of necroptosis. -- Highlights: ► Menadione causes mitochondrial superoxide accumulation and injury. ► Menadione-induced cell death is caspase-independent, due to rapid depletion of

  14. Isolated primary blast alters neuronal function with minimal cell death in organotypic hippocampal slice cultures.

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    Effgen, Gwen B; Vogel, Edward W; Lynch, Kimberly A; Lobel, Ayelet; Hue, Christopher D; Meaney, David F; Bass, Cameron R Dale; Morrison, Barclay

    2014-07-01

    An increasing number of U.S. soldiers are diagnosed with traumatic brain injury (TBI) subsequent to exposure to blast. In the field, blast injury biomechanics are highly complex and multi-phasic. The pathobiology caused by exposure to some of these phases in isolation, such as penetrating or inertially driven injuries, has been investigated extensively. However, it is unclear whether the primary component of blast, a shock wave, is capable of causing pathology on its own. Previous in vivo studies in the rodent and pig have demonstrated that it is difficult to deliver a primary blast (i.e., shock wave only) without rapid head accelerations and potentially confounding effects of inertially driven TBI. We have previously developed a well-characterized shock tube and custom in vitro receiver for exposing organotypic hippocampal slice cultures to pure primary blast. In this study, isolated primary blast induced minimal hippocampal cell death (on average, below 14% in any region of interest), even for the most severe blasts tested (424 kPa peak pressure, 2.3 ms overpressure duration, and 248 kPa*ms impulse). In contrast, measures of neuronal function were significantly altered at much lower exposures (336 kPa, 0.84 ms, and 86.5 kPa*ms), indicating that functional changes occur at exposures below the threshold for cell death. This is the first study to investigate a tolerance for primary blast-induced brain cell death in response to a range of blast parameters and demonstrate functional deficits at subthreshold exposures for cell death.

  15. Lead Exposure Disrupts Global DNA Methylation in Human Embryonic Stem Cells and Alters Their Neuronal Differentiation

    Science.gov (United States)

    Senut, Marie-Claude; Sen, Arko; Cingolani, Pablo; Shaik, Asra; Land, Susan J.; Ruden, Douglas M.

    2014-01-01

    Exposure to lead (Pb) during childhood can result in learning disabilities and behavioral problems. Although described in animal models, whether Pb exposure also alters neuronal differentiation in the developing brains of exposed children is unknown. Here, we investigated the effects of physiologically relevant concentrations of Pb (from 0.4 to 1.9μM) on the capacity of human embryonic stem cells (hESCs) to progress to a neuronal fate. We found that neither acute nor chronic exposure to Pb prevented hESCs from generating neural progenitor cells (NPCs). NPCs derived from hESCs chronically exposed to 1.9μM Pb throughout the neural differentiation process generated 2.5 times more TUJ1-positive neurons than those derived from control hESCs. Pb exposure of hESCs during the stage of neural rosette formation resulted in a significant decrease in the expression levels of the neural marker genes PAX6 and MSI1. Furthermore, the resulting NPCs differentiated into neurons with shorter neurites and less branching than control neurons, as assessed by Sholl analysis. DNA methylation studies of control, acutely treated hESCs and NPCs derived from chronically exposed hESCs using the Illumina HumanMethylation450 BeadChip demonstrated that Pb exposure induced changes in the methylation status of genes involved in neurogenetic signaling pathways. In summary, our study shows that exposure to Pb subtly alters the neuronal differentiation of exposed hESCs and that these changes could be partly mediated by modifications in the DNA methylation status of genes crucial to brain development. PMID:24519525

  16. Chronic alcohol alters dendritic spine development in neurons in primary culture.

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    Romero, Ana M; Renau-Piqueras, Jaime; Pilar Marin, M; Timoneda, Joaquin; Berciano, Maria T; Lafarga, Miguel; Esteban-Pretel, Guillermo

    2013-11-01

    Dendritic spines are specialised membrane protrusions of neuronal dendrites that receive the majority of excitatory synaptic inputs. Abnormal changes in their density, size and morphology have been associated with various neurological and psychiatric disorders, including those deriving from drug addiction. Dendritic spine formation, morphology and synaptic functions are governed by the actin cytoskeleton. Previous in vivo studies have shown that ethanol alters the number and morphology of spines, although the mechanisms underlying these alterations remain unknown. It has also been described how chronic ethanol exposure affects the levels, assembly and cellular organisation of the actin cytoskeleton in hippocampal neurons in primary culture. Therefore, we hypothesised that the ethanol-induced alterations in the number and shape of dendritic spines are due to alterations in the mechanisms regulating actin cytoskeleton integrity. The results presented herein show that chronic exposure to moderate levels of alcohol (30 mM) during the first 2 weeks of culture reduces dendritic spine density and alters the proportion of the different morphologies of these structures in hippocampal neurons, which affects the formation of mature spines. Apparently, these effects are associated with an increase in the G-actin/F-actin ratio due to a reduction of the F-actin fraction, leading to changes in the levels of the different factors regulating the organisation of this cytoskeletal component. The data presented herein indicate that these effects occur between weeks 1 and 2 of culture, an important period in dendritic spines development. These changes may be related to the dysfunction in the memory and learning processes present in children prenatally exposed to ethanol.

  17. Selective alterations of neurons and circuits related to early memory loss in Alzheimer's disease

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    María eLlorens-Martín

    2014-05-01

    Full Text Available A progressive loss of episodic memory is a well-known clinical symptom that characterizes Alzheimer’s disease (AD. The beginning of this loss of memory has been associated with the very early, pathological accumulation of tau and neuronal degeneration observed in the entorhinal cortex (EC. Tau-related pathology is thought to then spread progressively to the hippocampal formation and other brain areas as the disease progresses. The major cortical afferent source of the hippocampus and dentate gyrus is the EC through the perforant pathway. At least two main circuits participate in the connection between EC and the hippocampus; one originating in layer II and the other in layer III of the EC giving rise to the classical trisynaptic (ECII→dentate gyrus→CA3→CA1 and monosynaptic (ECIII→CA1 circuits. Thus, the study of the early pathological changes in these circuits is of great interest. In this review, we will discuss mainly the alterations of the granule cell neurons of the dentate gyrus and the atrophy of CA1 pyramidal neurons that occur in AD in relation to the possible differential alterations of these two main circuits.

  18. Cockayne syndrome-derived neurons display reduced synapse density and altered neural network synchrony.

    Science.gov (United States)

    Vessoni, Alexandre T; Herai, Roberto H; Karpiak, Jerome V; Leal, Angelica M S; Trujillo, Cleber A; Quinet, Annabel; Agnez Lima, Lucymara F; Menck, Carlos F M; Muotri, Alysson R

    2016-04-01

    Cockayne syndrome (CS) is a rare genetic disorder in which 80% of cases are caused by mutations in the Excision Repair Cross-Complementation group 6 gene (ERCC6). The encoded ERCC6 protein is more commonly referred to as Cockayne Syndrome B protein (CSB). Classical symptoms of CS patients include failure to thrive and a severe neuropathology characterized by microcephaly, hypomyelination, calcification and neuronal loss. Modeling the neurological aspect of this disease has proven difficult since murine models fail to mirror classical neurological symptoms. Therefore, a robust human in vitro cellular model would advance our fundamental understanding of the disease and reveal potential therapeutic targets. Herein, we successfully derived functional CS neural networks from human CS induced pluripotent stem cells (iPSCs) providing a new tool to facilitate studying this devastating disease. We identified dysregulation of the Growth Hormone/Insulin-like Growth Factor-1 (GH/IGF-1) pathway as well as pathways related to synapse formation, maintenance and neuronal differentiation in CSB neurons using unbiased RNA-seq gene expression analyses. Moreover, when compared to unaffected controls, CSB-deficient neural networks displayed altered electrophysiological activity, including decreased synchrony, and reduced synapse density. Collectively, our work reveals that CSB is required for normal neuronal function and we have established an alternative to previously available models to further study neural-specific aspects of CS. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Activity and High-Order Effective Connectivity Alterations in Sanfilippo C Patient-Specific Neuronal Networks

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    Isaac Canals

    2015-10-01

    Full Text Available Induced pluripotent stem cell (iPSC technology has been successfully used to recapitulate phenotypic traits of several human diseases in vitro. Patient-specific iPSC-based disease models are also expected to reveal early functional phenotypes, although this remains to be proved. Here, we generated iPSC lines from two patients with Sanfilippo type C syndrome, a lysosomal storage disorder with inheritable progressive neurodegeneration. Mature neurons obtained from patient-specific iPSC lines recapitulated the main known phenotypes of the disease, not present in genetically corrected patient-specific iPSC-derived cultures. Moreover, neuronal networks organized in vitro from mature patient-derived neurons showed early defects in neuronal activity, network-wide degradation, and altered effective connectivity. Our findings establish the importance of iPSC-based technology to identify early functional phenotypes, which can in turn shed light on the pathological mechanisms occurring in Sanfilippo syndrome. This technology also has the potential to provide valuable readouts to screen compounds, which can prevent the onset of neurodegeneration.

  20. Loss of neuron-astroglial interaction rapidly induces protective CNTF expression after stroke in mice

    Science.gov (United States)

    Kang, Seong Su; Keasey, Matthew P.; Cai, Jun; Hagg, Theo

    2012-01-01

    Ciliary neurotrophic factor (CNTF) is a potent neural cytokine with very low expression in the CNS, predominantly by astrocytes. CNTF increases rapidly and greatly following traumatic or ischemic injury. Understanding the underlying mechanisms would help to design pharmacological treatments to increase endogenous CNTF levels for neuroprotection. Here, we show that astroglial CNTF expression in the adult mouse striatum is increased two-fold within 1 hour and increases up to >30 fold over two weeks following a focal stroke caused by a transient middle cerebral artery occlusion (MCAO). Selective neuronal loss caused by intrastriatal injection of quinolinic acid resulted in a comparable increase. Co-cultured neurons reduced CNTF expression in astrocytes which was prevented by light trypsinization. RGD blocking peptides induced CNTF expression which was dependent on transcription. Astroglial CNTF expression was not affected by diffusible neuronal molecules or by neurotransmitters. The transient ischemia does not seem to directly increase CNTF, as intrastriatal injection of an ischemic solution or exposure of naive mice or cultured cells to severe hypoxia had minimal effects. Inflammatory mechanisms were probably also not involved, as intrastriatal injection of pro-inflammatory cytokines (IFNγ, IL6) in naive mice had no or small effects, and anti-inflammatory treatments did not diminish the increase in CNTF after MCAO. CNTF−/− mice had more extensive tissue loss and similar astrocyte activation after MCAO than their wildtype littermates. These data suggest that contact-mediated integrin signaling between neurons and astrocytes normally represses CNTF expression and that neuronal dysfunction causes a rapid protective response by the CNS. PMID:22764235

  1. IFN-beta-induced alteration of VSV protein phosphorylation in neuronal cells.

    Science.gov (United States)

    D'agostino, Paul M; Amenta, Jessica J; Reiss, Carol Shoshkes

    2009-12-01

    Vesicular stomatitis virus (VSV) replication is highly sensitive to interferon (IFN)-induced antiviral responses. VSV infection of well-known cell lines pretreated with IFN-beta results in a 10(4)-fold reduction in the release of infectious particles, with a concomitant abrogation in viral transcript and/or protein levels. However, in cell lines of neuronal lineage only a threefold reduction in viral transcript and protein levels was observed, despite the same 10(4)-fold reduction in released infectious virions, suggesting an assembly defect. Examination of VSV matrix (M) protein ubiquitination yielded no differences between mock- and IFN-beta-treated neuronal cells. Further analysis of potential post-translational modification events, by scintillation and two-dimensional electrophoretic methods, revealed IFN-beta-induced alterations in M protein and phosphoprotein (P) phosphorylation. Hypophosphorylated P protein was demonstrated by reduced (32)P counts, normalized by (35)S-cysteine/methionine incorporation, and by a shift in isoelectric focusing. Hypophosphorylation of VSV P protein was found to occur in neuronal cell lysates, but not within budded virions from the same IFN-beta-treated cells. In contrast, hyperphosphorylation of VSV M protein was observed in both cell lysates and viral particles from IFN-beta-treated neuronal cells. Hyperphosphorylated M protein was demonstrated by increased (32)P counts relative to (35)S-cysteine/methionine normalization, and by altered isoelectric focusing in protein populations from cell and viral lysates. Hyperphosphorylated VSV M protein was found to inhibit its association with VSV nucleocapsid, suggesting a possible mechanism for type I IFN-mediated misassembly through disruption of the interactions between ribonucleoprotein cores, and hyperphosphorylated M protein bound to the plasma membrane inner leaflet.

  2. Learning alters theta amplitude, theta-gamma coupling and neuronal synchronization in inferotemporal cortex

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    Nicol Alister U

    2011-06-01

    which are correlated with behavioral performance. A network model which can reproduce these changes suggests that a key function of such learning-evoked alterations in theta and theta-nested gamma activity may be increased temporal desynchronization in neuronal firing leading to optimal timing of inputs to downstream neural networks potentiating their responses. In this way learning can produce potentiation in neural networks simply through altering the temporal pattern of their inputs.

  3. Altered voltage-gated calcium channels in rat inferior colliculus neurons contribute to alcohol withdrawal seizures

    Science.gov (United States)

    N’Gouemo, Prosper

    2015-01-01

    We have previously reported that enhanced susceptibility to alcohol withdrawal seizures (AWS) parallels the enhancement of the current density of high-threshold voltage-gated Ca2+ (CaV) channels in rat inferior colliculus (IC) neurons. However, whether this increased current density is a cause or consequence of AWS is unclear. Here, I report changes in the current density of CaV channels in IC neurons during the course of alcohol withdrawal and the potential anticonvulsant effect of intra-IC infusions of L- and P-type CaV channel antagonists. Whole-cell currents were activated by depolarizing pulses using barium as the charge carrier. Currents and seizure susceptibility were evaluated in control animals 3 h after alcohol intoxication, as well as 3 h (before AWS), 24 h (when AWS susceptibility is maximal), and 48 h (when AWS susceptibility is no longer present) after alcohol withdrawal. Nifedipine, nimodipine (L-type antagonists) or ω-agatoxin TK (P-type antagonist) were infused intra-IC to probe the role of CaV channels in the pathogenesis of AWS. CaV current density and conductance in IC neurons were significantly increased 3 and 24 h after alcohol withdrawal compared with the control group or the group tested 3 h following ethanol intoxication. Blockade of L-type CaV channels within the IC completely suppressed AWS, and inhibition of P-type channels reduced AWS severity. These findings suggest that the enhancement of CaV currents in IC neurons occurs prior to AWS onset and that alterations in L- and P-type CaV channels in these neurons may underlie the pathogenesis of AWS. PMID:25914156

  4. Rapid Integration of Artificial Sensory Feedback during Operant Conditioning of Motor Cortex Neurons.

    Science.gov (United States)

    Prsa, Mario; Galiñanes, Gregorio L; Huber, Daniel

    2017-02-22

    Neuronal motor commands, whether generating real or neuroprosthetic movements, are shaped by ongoing sensory feedback from the displacement being produced. Here we asked if cortical stimulation could provide artificial feedback during operant conditioning of cortical neurons. Simultaneous two-photon imaging and real-time optogenetic stimulation were used to train mice to activate a single neuron in motor cortex (M1), while continuous feedback of its activity level was provided by proportionally stimulating somatosensory cortex. This artificial signal was necessary to rapidly learn to increase the conditioned activity, detect correct performance, and maintain the learned behavior. Population imaging in M1 revealed that learning-related activity changes are observed in the conditioned cell only, which highlights the functional potential of individual neurons in the neocortex. Our findings demonstrate the capacity of animals to use an artificially induced cortical channel in a behaviorally relevant way and reveal the remarkable speed and specificity at which this can occur. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Altered adult hippocampal neuronal maturation in a rat model of fetal alcohol syndrome.

    Science.gov (United States)

    Gil-Mohapel, Joana; Boehme, Fanny; Patten, Anna; Cox, Adrian; Kainer, Leah; Giles, Erica; Brocardo, Patricia S; Christie, Brian R

    2011-04-12

    Exposure to ethanol during pregnancy can be devastating to the developing nervous system, leading to significant central nervous system dysfunction. The hippocampus, one of the two brain regions where neurogenesis persists into adulthood, is particularly sensitive to the teratogenic effects of ethanol. In the present study, we tested a rat model of fetal alcohol syndrome (FAS) with ethanol administered via gavage throughout all three trimester equivalents. Subsequently, we assessed cell proliferation, as well as neuronal survival, and differentiation in the dentate gyrus of the hippocampus of adolescent (35 days old), young adult (60 days old) and adult (90 days old) Sprague-Dawley rats. Using both extrinsic (bromodeoxyuridine) and intrinsic (Ki-67) markers, we observed no significant alterations in cell proliferation and survival in ethanol-exposed animals when compared with their pair-fed and ad libitum controls. However, we detected a significant increase in the number of new immature neurons in animals that were exposed to ethanol throughout all three trimester equivalents. This result might reflect a compensatory mechanism to counteract the deleterious effects of prenatal ethanol exposure or an ethanol-induced arrest of the neurogenic process at the early neuronal maturation stages. Taken together these results indicate that exposure to ethanol during the period of brain development causes a long-lasting dysregulation of the neurogenic process, a mechanism that might contribute, at least in part, to the hippocampal deficits that have been reported in rodent models of FAS. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Loss of spatacsin function alters lysosomal lipid clearance leading to upper and lower motor neuron degeneration.

    Science.gov (United States)

    Branchu, Julien; Boutry, Maxime; Sourd, Laura; Depp, Marine; Leone, Céline; Corriger, Alexandrine; Vallucci, Maeva; Esteves, Typhaine; Matusiak, Raphaël; Dumont, Magali; Muriel, Marie-Paule; Santorelli, Filippo M; Brice, Alexis; El Hachimi, Khalid Hamid; Stevanin, Giovanni; Darios, Frédéric

    2017-06-01

    Mutations in SPG11 account for the most common form of autosomal recessive hereditary spastic paraplegia (HSP), characterized by a gait disorder associated with various brain alterations. Mutations in the same gene are also responsible for rare forms of Charcot-Marie-Tooth (CMT) disease and progressive juvenile-onset amyotrophic lateral sclerosis (ALS). To elucidate the physiopathological mechanisms underlying these human pathologies, we disrupted the Spg11 gene in mice by inserting stop codons in exon 32, mimicking the most frequent mutations found in patients. The Spg11 knockout mouse developed early-onset motor impairment and cognitive deficits. These behavioral deficits were associated with progressive brain atrophy with the loss of neurons in the primary motor cortex, cerebellum and hippocampus, as well as with accumulation of dystrophic axons in the corticospinal tract. Spinal motor neurons also degenerated and this was accompanied by fragmentation of neuromuscular junctions and muscle atrophy. This new Spg11 knockout mouse therefore recapitulates the full range of symptoms associated with SPG11 mutations observed in HSP, ALS and CMT patients. Examination of the cellular alterations observed in this model suggests that the loss of spatacsin leads to the accumulation of lipids in lysosomes by perturbing their clearance from these organelles. Altogether, our results link lysosomal dysfunction and lipid metabolism to neurodegeneration and pinpoint a critical role of spatacsin in lipid turnover. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Alterations of Ca2+ responsive proteins within cholinergic neurons in aging and AD

    Science.gov (United States)

    Riascos, David; Nicholas, Alexander; Samaeekia, Ravand; Yukhnanov, Rustam; Mesulam, M.-Marsel; Bigio, Eileen H.; Weintraub, Sandra; Guo, Ling; Geula, Changiz

    2014-01-01

    The molecular basis of selective neuronal vulnerability in Alzheimer ’s disease (AD) remains poorly understood. Using basal forebrain cholinergic neurons (BFCN) as a model and immunohistochemistry, we have demonstrated significant age-related loss of the calcium binding protein calbindin-D28K (CB) from BFCN, which was associated with tangle formation and degeneration in AD. Here we determined alterations in RNA and protein for CB and other Ca2+ responsive proteins Ca2+/calmodulin-dependent protein kinase I (CaMKI), growth-associated protein-43 (GAP43), calpain in the basal forebrain. We observed progressive downregulation of CB and CaMKI RNA in laser-captured BFCN in the normal-aged-AD continuum. We also detected progressive loss of CB, CaMKI-Delta, and GAP43 proteins in BF homogenates in aging and AD. Activated μ-calpain, a calcium-sensitive protease that degrades CaMKI and GAP-43, was significantly increased in the normal aged BF and was 10-times higher in AD BF. Overactivation of μ-calpain was confirmed using proteolytic fragments of its substrate spectrin. Substantial age and AD related alterations in Ca2+-sensing proteins most likely contribute to selective vulnerability of BFCN to degeneration in AD. PMID:24461366

  8. No neuronal loss, but alterations of the GDNF system in asymptomatic diverticulosis.

    Science.gov (United States)

    Barrenschee, Martina; Wedel, Thilo; Lange, Christina; Hohmeier, Ines; Cossais, François; Ebsen, Michael; Vogel, Ilka; Böttner, Martina

    2017-01-01

    Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor known to promote the survival and maintenance of neurons not only in the developing but also in the adult enteric nervous system. As diverticular disease (DD) is associated with reduced myenteric neurons, alterations of the GDNF system were studied in asymptomatic diverticulosis (diverticulosis) and DD. Morphometric analysis for quantifying myenteric ganglia and neurons were assessed in colonic full-thickness sections of patients with diverticulosis and controls. Samples of tunica muscularis (TM) and laser-microdissected myenteric ganglia from patients with diverticulosis, DD and controls were analyzed for mRNA expression levels of GDNF, GFRA1, and RET by RT-qPCR. Myenteric protein expression of both receptors was quantified by fluorescence-immunohistochemistry of patients with diverticulosis, DD, and controls. Although no myenteric morphometric alterations were found in patients with diverticulosis, GDNF, GFRA1 and RET mRNA expression was down-regulated in the TM of patients with diverticulosis as well as DD. Furthermore GFRA1 and RET myenteric plexus mRNA expression of patients with diverticulosis and DD was down-regulated, whereas GDNF remained unaltered. Myenteric immunoreactivity of the receptors GFRα1 and RET was decreased in both asymptomatic diverticulosis and DD patients. Our data provide evidence for an impaired GDNF system at gene and protein level not only in DD but also during early stages of diverticula formation. Thus, the results strengthen the idea of a disturbed GDNF-responsiveness as contributive factor for a primary enteric neuropathy involved in the pathogenesis and disturbed intestinal motility observed in DD.

  9. No neuronal loss, but alterations of the GDNF system in asymptomatic diverticulosis.

    Directory of Open Access Journals (Sweden)

    Martina Barrenschee

    Full Text Available Glial cell line-derived neurotrophic factor (GDNF is a potent neurotrophic factor known to promote the survival and maintenance of neurons not only in the developing but also in the adult enteric nervous system. As diverticular disease (DD is associated with reduced myenteric neurons, alterations of the GDNF system were studied in asymptomatic diverticulosis (diverticulosis and DD.Morphometric analysis for quantifying myenteric ganglia and neurons were assessed in colonic full-thickness sections of patients with diverticulosis and controls. Samples of tunica muscularis (TM and laser-microdissected myenteric ganglia from patients with diverticulosis, DD and controls were analyzed for mRNA expression levels of GDNF, GFRA1, and RET by RT-qPCR. Myenteric protein expression of both receptors was quantified by fluorescence-immunohistochemistry of patients with diverticulosis, DD, and controls.Although no myenteric morphometric alterations were found in patients with diverticulosis, GDNF, GFRA1 and RET mRNA expression was down-regulated in the TM of patients with diverticulosis as well as DD. Furthermore GFRA1 and RET myenteric plexus mRNA expression of patients with diverticulosis and DD was down-regulated, whereas GDNF remained unaltered. Myenteric immunoreactivity of the receptors GFRα1 and RET was decreased in both asymptomatic diverticulosis and DD patients.Our data provide evidence for an impaired GDNF system at gene and protein level not only in DD but also during early stages of diverticula formation. Thus, the results strengthen the idea of a disturbed GDNF-responsiveness as contributive factor for a primary enteric neuropathy involved in the pathogenesis and disturbed intestinal motility observed in DD.

  10. Adaptive Neuron Model: An architecture for the rapid learning of nonlinear topological transformations

    Science.gov (United States)

    Tawel, Raoul (Inventor)

    1994-01-01

    A method for the rapid learning of nonlinear mappings and topological transformations using a dynamically reconfigurable artificial neural network is presented. This fully-recurrent Adaptive Neuron Model (ANM) network was applied to the highly degenerate inverse kinematics problem in robotics, and its performance evaluation is bench-marked. Once trained, the resulting neuromorphic architecture was implemented in custom analog neural network hardware and the parameters capturing the functional transformation downloaded onto the system. This neuroprocessor, capable of 10(exp 9) ops/sec, was interfaced directly to a three degree of freedom Heathkit robotic manipulator. Calculation of the hardware feed-forward pass for this mapping was benchmarked at approximately 10 microsec.

  11. Altered intrinsic excitability of hippocampal CA1 pyramidal neurons in aged PDAPP mice

    Directory of Open Access Journals (Sweden)

    Francesco eTamagnini

    2015-10-01

    Full Text Available Amyloidopathy involves the accumulation of insoluble amyloid β (Aβ species in the brain’s parenchyma and is a key histopathological hallmark of Alzheimer’s disease (AD. Work on transgenic mice that overexpress A suggests that elevated A levels in the brain are associated with aberrant epileptiform activity and increased intrinsic excitability of CA1 hippocampal neurons. In this study we examined if similar changes could be observed in hippocampal CA1 pyramidal neurons from aged PDAPP mice (20-23 month old, Indiana mutation: V717F on APP gene compared to their age-matched WT littermate controls. Whole-cell current clamp recordings revealed that sub-threshold intrinsic properties, such as input resistance, resting membrane potential and hyperpolarization activated sag were unaffected, but capacitance was significantly decreased in the transgenic animals. No differences between genotypes were observed in the overall number of action potentials (AP elicited by 500 ms supra-threshold current stimuli. PDAPP neurons, however, exhibited higher instantaneous firing frequencies after accommodation in response to high intensity current injections. The AP waveform was narrower and shorter in amplitude in PDAPP mice: these changes, according to our in silico model of a CA1/3 pyramidal neuron, depended on the respective reduction and increase of Na+ and K+ voltage-gated channels maximal conductances. Finally, the after-hyperpolarization (AHP, seen after the first AP evoked by a +300 pA current injection and after 50 Hz AP bursts, was more pronounced in PDAPP mice.These data show that Aβ-overexpression in aged mice altered the capacitance, the neuronal firing and the AP waveform of CA1 pyramidal neurons. Some of these findings are consistent with previous work on younger PDAPP, they also show important differences that can be potentially ascribed to the interaction between amyloidopathy and ageing. Such a change of IE properties over time

  12. Prenatal exposure to urban air nanoparticles in mice causes altered neuronal differentiation and depression-like responses.

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    David A Davis

    Full Text Available Emerging evidence suggests that excessive exposure to traffic-derived air pollution during pregnancy may increase the vulnerability to neurodevelopmental alterations that underlie a broad array of neuropsychiatric disorders. We present a mouse model for prenatal exposure to urban freeway nanoparticulate matter (nPM. In prior studies, we developed a model for adult rodent exposure to re-aerosolized urban nPM which caused inflammatory brain responses with altered neuronal glutamatergic functions. nPMs are collected continuously for one month from a local freeway and stored as an aqueous suspension, prior to re-aerosolization for exposure of mice under controlled dose and duration. This paradigm was used for a pilot study of prenatal nPM impact on neonatal neurons and adult behaviors. Adult C57BL/6J female mice were exposed to re-aerosolized nPM (350 µg/m(3 or control filtered ambient air for 10 weeks (3×5 hour exposures per week, encompassing gestation and oocyte maturation prior to mating. Prenatal nPM did not alter litter size, pup weight, or postnatal growth. Neonatal cerebral cortex neurons at 24 hours in vitro showed impaired differentiation, with 50% reduction of stage 3 neurons with long neurites and correspondingly more undifferentiated neurons at Stages 0 and 1. Neuron number after 24 hours of culture was not altered by prenatal nPM exposure. Addition of exogenous nPM (2 µg/ml to the cultures impaired pyramidal neuron Stage 3 differentiation by 60%. Adult males showed increased depression-like responses in the tail-suspension test, but not anxiety-related behaviors. These pilot data suggest that prenatal exposure to nPM can alter neuronal differentiation with gender-specific behavioral sequelae that may be relevant to human prenatal exposure to urban vehicular aerosols.

  13. Neuronal Cell Death Induced by Mechanical Percussion Trauma in Cultured Neurons is not Preceded by Alterations in Glucose, Lactate and Glutamine Metabolism

    DEFF Research Database (Denmark)

    Jayakumar, A R; Bak, L K; Rama Rao, K V

    2016-01-01

    dysfunction and subsequent energy failure play a role in the pathogenesis of TBI. We therefore examined whether oxidative metabolism of (13)C-labeled glucose, lactate or glutamine is altered early following in vitro mechanical percussion-induced trauma (5 atm) to neurons (4-24 h), and whether such events...

  14. Brain-region–specific alterations of the trajectories of neuronal volume growth throughout the lifespan in autism

    Science.gov (United States)

    2014-01-01

    Several morphometric studies have revealed smaller than normal neurons in the neocortex of autistic subjects. To test the hypothesis that abnormal neuronal growth is a marker of an autism-associated global encephalopathy, neuronal volumes were estimated in 16 brain regions, including various subcortical structures, Ammon’s horn, archicortex, cerebellum, and brainstem in 14 brains from individuals with autism 4 to 60 years of age and 14 age-matched control brains. This stereological study showed a significantly smaller volume of neuronal soma in 14 of 16 regions in the 4- to 8-year-old autistic brains than in the controls. Arbitrary classification revealed a very severe neuronal volume deficit in 14.3% of significantly altered structures, severe in 50%, moderate in 21.4%, and mild in 14.3% structures. This pattern suggests desynchronized neuronal growth in the interacting neuronal networks involved in the autistic phenotype. The comparative study of the autistic and control subject brains revealed that the number of structures with a significant volume deficit decreased from 14 in the 4- to 8-year-old autistic subjects to 4 in the 36- to 60-year-old. Neuronal volumes in 75% of the structures examined in the older adults with autism are comparable to neuronal volume in age-matched controls. This pattern suggests defects of neuronal growth in early childhood and delayed up-regulation of neuronal growth during adolescence and adulthood reducing neuron soma volume deficit in majority of examined regions. However, significant correction of neuron size but limited clinical improvements suggests that delayed correction does not restore functional deficits. PMID:24612906

  15. Recycling endosomes undergo rapid closure of a fusion pore on exocytosis in neuronal dendrites.

    Science.gov (United States)

    Jullié, Damien; Choquet, Daniel; Perrais, David

    2014-08-13

    Exocytosis of recycling endosomes (REs) represents the last step of receptor and membrane recycling, a fundamental process involved in many aspects of cell physiology. In neurons, it is involved in the control of cell polarity and synaptic plasticity and is locally and tightly regulated. However, its molecular mechanisms are still poorly understood. We have imaged single exocytosis events of REs in rat hippocampal neurons in culture transfected with three types of receptors tagged with the pH-sensitive GFP mutant superecliptic phluorin. We found that exocytosis events are grouped into two categories: (1) short burst events in which receptors diffuse into the plasma membrane in a few seconds; and (2) long display events in which receptors remain visible and clustered after exocytosis for many seconds. Display events are much rarer in non-neuronal cells, such as fibroblasts and astrocytes. Using two-color imaging and fast extracellular solution changes, we show that display events correspond to the rapid opening and closing of a fusion pore (or "kiss-and-run") with a median opening time of 2.6 s, which restricts the diffusion of multiple receptor types and bound cargo. Moreover, the RE marker Rab11 remains enriched after display exocytosis events and controls the mode of RE exocytosis. Finally, a given RE can undergo multiple rounds of display exocytosis. The last step of recycling can thus be controlled in neurons for the selective delivery of receptors at the cell surface. Copyright © 2014 the authors 0270-6474/14/3411106-13$15.00/0.

  16. DNA methylation alterations in iPSC- and hESC-derived neurons: potential implications for neurological disease modeling.

    Science.gov (United States)

    de Boni, Laura; Gasparoni, Gilles; Haubenreich, Carolin; Tierling, Sascha; Schmitt, Ina; Peitz, Michael; Koch, Philipp; Walter, Jörn; Wüllner, Ullrich; Brüstle, Oliver

    2018-01-01

    Genetic predisposition and epigenetic alterations are both considered to contribute to sporadic neurodegenerative diseases (NDDs) such as Parkinson's disease (PD). Since cell reprogramming and the generation of induced pluripotent stem cells (iPSCs) are themselves associated with major epigenetic remodeling, it remains unclear to what extent iPSC-derived neurons lend themselves to model epigenetic disease-associated changes. A key question to be addressed in this context is whether iPSC-derived neurons exhibit epigenetic signatures typically observed in neurons derived from non-reprogrammed human embryonic stem cells (hESCs). Here, we compare mature neurons derived from hESC and isogenic human iPSC generated from hESC-derived neural stem cells. Genome-wide 450 K-based DNA methylation and HT12v4 gene array expression analyses were complemented by a deep analysis of selected genes known to be involved in NDD. Our studies show that DNA methylation and gene expression patterns of isogenic hESC- and iPSC-derived neurons are markedly preserved on a genome-wide and single gene level. Overall, iPSC-derived neurons exhibit similar DNA methylation patterns compared to isogenic hESC-derived neurons. Further studies will be required to explore whether the epigenetic patterns observed in iPSC-derived neurons correspond to those detectable in native brain neurons.

  17. Alterations in cortical thickness and neuronal density in the frontal cortex of Albert Einstein.

    Science.gov (United States)

    Anderson, B; Harvey, T

    1996-06-07

    Neuronal density, neuron size, and the number of neurons under 1 mm2 of cerebral cortical surface area were measured in the right pre-frontal cortex of Albert Einstein and five elderly control subjects. Measurement of neuronal density used the optical dissector technique on celloidin-embedded cresyl violet-stained sections. The neurons counted provided a systematic random sample for the measurement of cell body cross-sectional area. Einstein's cortex did not differ from the control subjects in the number of neurons under 1 mm2 of cerebral cortex or in mean neuronal size. Because Einstein's cortex was thinner than the controls he had a greater neuronal density.

  18. Developmental alterations in motor coordination and medium spiny neuron markers in mice lacking pgc-1α.

    Directory of Open Access Journals (Sweden)

    Elizabeth K Lucas

    Full Text Available Accumulating evidence implicates the transcriptional coactivator peroxisome proliferator activated receptor γ coactivator 1α (PGC-1α in the pathophysiology of Huntington Disease (HD. Adult PGC-1α (-/- mice exhibit striatal neurodegeneration, and reductions in the expression of PGC-1α have been observed in striatum and muscle of HD patients as well as in animal models of the disease. However, it is unknown whether decreased expression of PGC-1α alone is sufficient to lead to the motor phenotype and striatal pathology characteristic of HD. For the first time, we show that young PGC-1α (-/- mice exhibit severe rotarod deficits, decreased rearing behavior, and increased occurrence of tremor in addition to the previously described hindlimb clasping. Motor impairment and striatal vacuolation are apparent in PGC-1α (-/- mice by four weeks of age and do not improve or decline by twelve weeks of age. The behavioral and pathological phenotype of PGC-1α (-/- mice can be completely recapitulated by conditional nervous system deletion of PGC-1α, indicating that peripheral effects are not responsible for the observed abnormalities. Evaluation of the transcriptional profile of PGC-1α (-/- striatal neuron populations and comparison to striatal neuron profiles of R6/2 HD mice revealed that PGC-1α deficiency alone is not sufficient to cause the transcriptional changes observed in this HD mouse model. In contrast to R6/2 HD mice, PGC-1α (-/- mice show increases in the expression of medium spiny neuron (MSN markers with age, suggesting that the observed behavioral and structural abnormalities are not primarily due to MSN loss, the defining pathological feature of HD. These results indicate that PGC-1α is required for the proper development of motor circuitry and transcriptional homeostasis in MSNs and that developmental disruption of PGC-1α leads to long-term alterations in motor functioning.

  19. Neonicotinoid Insecticides Alter the Gene Expression Profile of Neuron-Enriched Cultures from Neonatal Rat Cerebellum.

    Science.gov (United States)

    Kimura-Kuroda, Junko; Nishito, Yasumasa; Yanagisawa, Hiroko; Kuroda, Yoichiro; Komuta, Yukari; Kawano, Hitoshi; Hayashi, Masaharu

    2016-10-04

    Neonicotinoids are considered safe because of their low affinities to mammalian nicotinic acetylcholine receptors (nAChRs) relative to insect nAChRs. However, because of importance of nAChRs in mammalian brain development, there remains a need to establish the safety of chronic neonicotinoid exposures with regards to children's health. Here we examined the effects of longterm (14 days) and low dose (1 μM) exposure of neuron-enriched cultures from neonatal rat cerebellum to nicotine and two neonicotinoids: acetamiprid and imidacloprid. Immunocytochemistry revealed no differences in the number or morphology of immature neurons or glial cells in any group versus untreated control cultures. However, a slight disturbance in Purkinje cell dendritic arborization was observed in the exposed cultures. Next we performed transcriptome analysis on total RNAs using microarrays, and identified significant differential expression (p neonicotinoid exposure alters the transcriptome of the developing mammalian brain in a similar way to nicotine exposure. Our results highlight the need for further careful investigations into the effects of neonicotinoids in the developing mammalian brain.

  20. Neonicotinoid Insecticides Alter the Gene Expression Profile of Neuron-Enriched Cultures from Neonatal Rat Cerebellum

    Directory of Open Access Journals (Sweden)

    Junko Kimura-Kuroda

    2016-10-01

    Full Text Available Neonicotinoids are considered safe because of their low affinities to mammalian nicotinic acetylcholine receptors (nAChRs relative to insect nAChRs. However, because of importance of nAChRs in mammalian brain development, there remains a need to establish the safety of chronic neonicotinoid exposures with regards to children’s health. Here we examined the effects of longterm (14 days and low dose (1 μM exposure of neuron-enriched cultures from neonatal rat cerebellum to nicotine and two neonicotinoids: acetamiprid and imidacloprid. Immunocytochemistry revealed no differences in the number or morphology of immature neurons or glial cells in any group versus untreated control cultures. However, a slight disturbance in Purkinje cell dendritic arborization was observed in the exposed cultures. Next we performed transcriptome analysis on total RNAs using microarrays, and identified significant differential expression (p < 0.05, q < 0.05, ≥1.5 fold between control cultures versus nicotine-, acetamiprid-, or imidacloprid-exposed cultures in 34, 48, and 67 genes, respectively. Common to all exposed groups were nine genes essential for neurodevelopment, suggesting that chronic neonicotinoid exposure alters the transcriptome of the developing mammalian brain in a similar way to nicotine exposure. Our results highlight the need for further careful investigations into the effects of neonicotinoids in the developing mammalian brain.

  1. Altered neuronal excitability underlies impaired hippocampal function in an animal model of psychosis

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    Thomas eGrüter

    2015-05-01

    Full Text Available Psychosis is accompanied by severe attentional deficits, and impairments in associational-memory processing and sensory information processing that are ascribed to dysfunctions in prefrontal and hippocampal function. Disruptions of glutamatergic signalling may underlie these alterations: Antagonism of the N-methyl-D-aspartate receptor (NMDAR results in similar molecular, cellular, cognitive and behavioural changes in rodents and/or humans as those that occur in psychosis, raising the question as to whether changes in glutamatergic transmission may be intrinsic to the pathophysiology of the disease. In an animal model of psychosis that comprises treatment with the irreversible NMDAR-antagonist, MK801, we explored the cellular mechanisms that may underlie hippocampal dysfunction in psychosis. MK801-treatment resulted in a profound loss of hippocampal LTP that was evident 4 weeks after treatment. Whereas neuronal expression of the immediate early gene, Arc, was enhanced in the hippocampus by spatial learning in controls, MK801-treated animals failed to show activity-dependent increases in Arc expression. By contrast, a significant increase in basal Arc expression in the absence of learning was evident compared to controls. Paired-pulse facilitation was increased at the 40 ms interval indicating that NMDAR and/or fast GABAergic-mediated neurotransmission was disrupted. In line with this, MK801-treatment resulted in a significant decrease in GABA(A, and increase in GABA(B-receptor-expression in PFC, along with a significant increase of GABA(B- and NMDAR-GluN2B expression in the dentate gyrus. NMDAR-GluN1 or GluN2A subunit expression was unchanged. These data suggest that in psychosis, deficits in hippocampus-dependent memory may be caused by a loss of hippocampal LTP that arises through enhanced hippocampal neuronal excitability, altered GluN2B and GABA receptor expression and an uncoupling of the hippocampus-prefrontal cortex circuitry.

  2. Prenatal exposure to cannabinoids evokes long-lasting functional alterations by targeting CB1 receptors on developing cortical neurons.

    Science.gov (United States)

    de Salas-Quiroga, Adán; Díaz-Alonso, Javier; García-Rincón, Daniel; Remmers, Floortje; Vega, David; Gómez-Cañas, María; Lutz, Beat; Guzmán, Manuel; Galve-Roperh, Ismael

    2015-11-03

    The CB1 cannabinoid receptor, the main target of Δ(9)-tetrahydrocannabinol (THC), the most prominent psychoactive compound of marijuana, plays a crucial regulatory role in brain development as evidenced by the neurodevelopmental consequences of its manipulation in animal models. Likewise, recreational cannabis use during pregnancy affects brain structure and function of the progeny. However, the precise neurobiological substrates underlying the consequences of prenatal THC exposure remain unknown. As CB1 signaling is known to modulate long-range corticofugal connectivity, we analyzed the impact of THC exposure on cortical projection neuron development. THC administration to pregnant mice in a restricted time window interfered with subcerebral projection neuron generation, thereby altering corticospinal connectivity, and produced long-lasting alterations in the fine motor performance of the adult offspring. Consequences of THC exposure were reminiscent of those elicited by CB1 receptor genetic ablation, and CB1-null mice were resistant to THC-induced alterations. The identity of embryonic THC neuronal targets was determined by a Cre-mediated, lineage-specific, CB1 expression-rescue strategy in a CB1-null background. Early and selective CB1 reexpression in dorsal telencephalic glutamatergic neurons but not forebrain GABAergic neurons rescued the deficits in corticospinal motor neuron development of CB1-null mice and restored susceptibility to THC-induced motor alterations. In addition, THC administration induced an increase in seizure susceptibility that was mediated by its interference with CB1-dependent regulation of both glutamatergic and GABAergic neuron development. These findings demonstrate that prenatal exposure to THC has long-lasting deleterious consequences in the adult offspring solely mediated by its ability to disrupt the neurodevelopmental role of CB1 signaling.

  3. Fear conditioning leads to alteration in specific genes expression in cortical and thalamic neurons that project to the lateral amygdala.

    Science.gov (United States)

    Katz, Ira K; Lamprecht, Raphael

    2015-02-01

    RNA transcription is needed for memory formation. However, the ability to identify genes whose expression is altered by learning is greatly impaired because of methodological difficulties in profiling gene expression in specific neurons involved in memory formation. Here, we report a novel approach to monitor the expression of genes after learning in neurons in specific brain pathways needed for memory formation. In this study, we aimed to monitor gene expression after fear learning. We retrogradely labeled discrete thalamic neurons that project to the lateral amygdala (LA) of rats. The labeled neurons were dissected, using laser microdissection microscopy, after fear conditioning learning or unpaired training. The RNAs from the dissected neurons were subjected to microarray analysis. The levels of selected RNAs detected by the microarray analysis to be altered by fear conditioning were also assessed by nanostring analysis. We observed that the expression of genes involved in the regulation of translation, maturation and degradation of proteins was increased 6 h after fear conditioning compared to unpaired or naïve trained rats. These genes were not expressed 24 h after training or in cortical neurons that project to the LA. The expression of genes involved in transcription regulation and neuronal development was altered after fear conditioning learning in the cortical-LA pathway. The present study provides key information on the identity of genes expressed in discrete thalamic and cortical neurons that project to the LA after fear conditioning. Such an approach could also serve to identify gene products as targets for the development of a new generation of therapeutic agents that could be aimed to functionally identified brain circuits to treat memory-related disorders. © 2014 International Society for Neurochemistry.

  4. Rapid Sequential in Situ Multiplexing with DNA Exchange Imaging in Neuronal Cells and Tissues.

    Science.gov (United States)

    Wang, Yu; Woehrstein, Johannes B; Donoghue, Noah; Dai, Mingjie; Avendaño, Maier S; Schackmann, Ron C J; Zoeller, Jason J; Wang, Shan Shan H; Tillberg, Paul W; Park, Demian; Lapan, Sylvain W; Boyden, Edward S; Brugge, Joan S; Kaeser, Pascal S; Church, George M; Agasti, Sarit S; Jungmann, Ralf; Yin, Peng

    2017-10-11

    To decipher the molecular mechanisms of biological function, it is critical to map the molecular composition of individual cells or even more importantly tissue samples in the context of their biological environment in situ. Immunofluorescence (IF) provides specific labeling for molecular profiling. However, conventional IF methods have finite multiplexing capabilities due to spectral overlap of the fluorophores. Various sequential imaging methods have been developed to circumvent this spectral limit but are not widely adopted due to the common limitation of requiring multirounds of slow (typically over 2 h at room temperature to overnight at 4 °C in practice) immunostaining. We present here a practical and robust method, which we call DNA Exchange Imaging (DEI), for rapid in situ spectrally unlimited multiplexing. This technique overcomes speed restrictions by allowing for single-round immunostaining with DNA-barcoded antibodies, followed by rapid (less than 10 min) buffer exchange of fluorophore-bearing DNA imager strands. The programmability of DEI allows us to apply it to diverse microscopy platforms (with Exchange Confocal, Exchange-SIM, Exchange-STED, and Exchange-PAINT demonstrated here) at multiple desired resolution scales (from ∼300 nm down to sub-20 nm). We optimized and validated the use of DEI in complex biological samples, including primary neuron cultures and tissue sections. These results collectively suggest DNA exchange as a versatile, practical platform for rapid, highly multiplexed in situ imaging, potentially enabling new applications ranging from basic science, to drug discovery, and to clinical pathology.

  5. Prion replication occurs in endogenous adult neural stem cells and alters their neuronal fate: involvement of endogenous neural stem cells in prion diseases.

    Directory of Open Access Journals (Sweden)

    Aroa Relaño-Ginès

    Full Text Available Prion diseases are irreversible progressive neurodegenerative diseases, leading to severe incapacity and death. They are characterized in the brain by prion amyloid deposits, vacuolisation, astrocytosis, neuronal degeneration, and by cognitive, behavioural and physical impairments. There is no treatment for these disorders and stem cell therapy therefore represents an interesting new approach. Gains could not only result from the cell transplantation, but also from the stimulation of endogenous neural stem cells (NSC or by the combination of both approaches. However, the development of such strategies requires a detailed knowledge of the pathology, particularly concerning the status of the adult neurogenesis and endogenous NSC during the development of the disease. During the past decade, several studies have consistently shown that NSC reside in the adult mammalian central nervous system (CNS and that adult neurogenesis occurs throughout the adulthood in the subventricular zone of the lateral ventricle or the Dentate Gyrus of the hippocampus. Adult NSC are believed to constitute a reservoir for neuronal replacement during normal cell turnover or after brain injury. However, the activation of this system does not fully compensate the neuronal loss that occurs during neurodegenerative diseases and could even contribute to the disease progression. We investigated here the status of these cells during the development of prion disorders. We were able to show that NSC accumulate and replicate prions. Importantly, this resulted in the alteration of their neuronal fate which then represents a new pathologic event that might underlie the rapid progression of the disease.

  6. Oral intake of zirconia nanoparticle alters neuronal development and behaviour of Drosophila melanogaster

    Science.gov (United States)

    Mishra, Monalisa; Sabat, Debabrat; Ekka, Basanti; Sahu, Swetapadma; P, Unnikannan; Dash, Priyabrat

    2017-08-01

    Zirconia nanoparticles (ZrO2 NPs) have been extensively used in teeth and bone implants and thus get a chance to interact with the physiological system. The current study investigated the oral administration of various concentrations of ZrO2 NPs synthesized by the hydrothermal method (0.25 to 5.0 mg L-1) on Drosophila physiology and behaviour. The size of the currently studied nanoparticle varies from 10 to 12 nm. ZrO2 NPs accumulated within the gut in a concentration-dependent manner and generate reactive oxygen species (ROS) only at 2.5 and 5.0 mg L-1 concentrations. ROS was detected by nitroblue tetrazolium (NBT) assay and 2',7'-dichlorofluorescein http://www.ncbi.nlm.nih.gov/pubmed/20370560 (H2DCF) staining. The ROS toxicity alters the larval gut structure as revealed by DAPI staining. The NP stress of larvae affects the Drosophila development by distressing pupa count and varying the phenotypic changes in sensory organs (eye, thorax bristle, wings). Besides phenotypic changes, flawed climbing behaviour against gravity was seen in ZrO2 NP-treated flies. All together, for the first time, we have reported that a ROS-mediated ZrO2 NP toxicity alters neuronal development and functioning using Drosophila as a model organism. [Figure not available: see fulltext.

  7. Phencyclidine rapidly decreases neuronal mRNA of brain-derived neurotrophic factor.

    Science.gov (United States)

    Katanuma, Yusuke; Numakawa, Tadahiro; Adachi, Naoki; Yamamoto, Noriko; Ooshima, Yoshiko; Odaka, Haruki; Inoue, Takafumi; Kunugi, Hiroshi

    2014-06-01

    Downregulation of brain-derived neurotrophic factor (BDNF), a member of neurotrophin family, has been implicated in psychiatric diseases including schizophrenia. However, detailed mechanisms of its reduction in patients with schizophrenia remain unclear. Here, using cultured cortical neurons, we monitored BDNF mRNA levels following acute application of phencyclidine [PCP; an N-methyl-d-aspartate (NMDA) receptor blocker], which is known to produce schizophrenia-like symptoms. We found that PCP rapidly caused a reduction in total amount of BDNF transcripts without effect on cell viability, while mRNA levels of nerve growth factor was intact. Actinomycin-D (ActD), an RNA synthesis inhibitor, decreased total BDNF mRNA levels similar to PCP, and coapplication of ActD with PCP did not show further reduction in BDNF mRNA compared with solo application of each drug. Among BDNF exons I, IV, and VI, the exon IV, which is positively regulated by neuronal activity, was highly sensitive to PCP. Furthermore, PCP inactivated cAMP response element-binding protein (CREB; a regulator of transcriptional activity of exon IV). The inactivation of CREB was also achieved by an inhibitor for Ca(2+) /calmodulin kinase II (CaMKII), although coapplication with PCP induced no further inhibition on the CREB activity. It is possible that PCP decreases BDNF transcription via blocking the NMDA receptor/CaMKII/CREB signaling. Copyright © 2014 Wiley Periodicals, Inc.

  8. Menthol Alone Upregulates Midbrain nAChRs, Alters nAChR Subtype Stoichiometry, Alters Dopamine Neuron Firing Frequency, and Prevents Nicotine Reward.

    Science.gov (United States)

    Henderson, Brandon J; Wall, Teagan R; Henley, Beverley M; Kim, Charlene H; Nichols, Weston A; Moaddel, Ruin; Xiao, Cheng; Lester, Henry A

    2016-03-09

    Upregulation of β2 subunit-containing (β2*) nicotinic acetylcholine receptors (nAChRs) is implicated in several aspects of nicotine addiction, and menthol cigarette smokers tend to upregulate β2* nAChRs more than nonmenthol cigarette smokers. We investigated the effect of long-term menthol alone on midbrain neurons containing nAChRs. In midbrain dopaminergic (DA) neurons from mice containing fluorescent nAChR subunits, menthol alone increased the number of α4 and α6 nAChR subunits, but this upregulation did not occur in midbrain GABAergic neurons. Thus, chronic menthol produces a cell-type-selective upregulation of α4* nAChRs, complementing that of chronic nicotine alone, which upregulates α4 subunit-containing (α4*) nAChRs in GABAergic but not DA neurons. In mouse brain slices and cultured midbrain neurons, menthol reduced DA neuron firing frequency and altered DA neuron excitability following nAChR activation. Furthermore, menthol exposure before nicotine abolished nicotine reward-related behavior in mice. In neuroblastoma cells transfected with fluorescent nAChR subunits, exposure to 500 nm menthol alone also increased nAChR number and favored the formation of (α4)3(β2)2 nAChRs; this contrasts with the action of nicotine itself, which favors (α4)2(β2)3 nAChRs. Menthol alone also increases the number of α6β2 receptors that exclude the β3 subunit. Thus, menthol stabilizes lower-sensitivity α4* and α6 subunit-containing nAChRs, possibly by acting as a chemical chaperone. The abolition of nicotine reward-related behavior may be mediated through menthol's ability to stabilize lower-sensitivity nAChRs and alter DA neuron excitability. We conclude that menthol is more than a tobacco flavorant: administered alone chronically, it alters midbrain DA neurons of the nicotine reward-related pathway. Copyright © 2016 the authors 0270-6474/16/362957-18$15.00/0.

  9. PCB 136 atropselectively alters morphometric and functional parameters of neuronal connectivity in cultured rat hippocampal neurons via ryanodine receptor-dependent mechanisms.

    Science.gov (United States)

    Yang, Dongren; Kania-Korwel, Izabela; Ghogha, Atefeh; Chen, Hao; Stamou, Marianna; Bose, Diptiman D; Pessah, Isaac N; Lehmler, Hans-Joachim; Lein, Pamela J

    2014-04-01

    We recently demonstrated that polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substitutions sensitize ryanodine receptors (RyRs), and this activity promotes Ca²⁺-dependent dendritic growth in cultured neurons. Many ortho-substituted congeners display axial chirality, and we previously reported that the chiral congener PCB 136 (2,2',3,3',6,6'-hexachlorobiphenyl) atropselectively sensitizes RyRs. Here, we test the hypothesis that PCB 136 atropisomers differentially alter dendritic growth and other parameters of neuronal connectivity influenced by RyR activity. (-)-PCB 136, which potently sensitizes RyRs, enhances dendritic growth in primary cultures of rat hippocampal neurons, whereas (+)-PCB 136, which lacks RyR activity, has no effect on dendritic growth. The dendrite-promoting activity of (-)-PCB 136 is observed at concentrations ranging from 0.1 to 100 nM and is blocked by pharmacologic RyR antagonism. Neither atropisomer alters axonal growth or cell viability. Quantification of PCB 136 atropisomers in hippocampal cultures indicates that atropselective effects on dendritic growth are not due to differential partitioning of atropisomers into cultured cells. Imaging of hippocampal neurons loaded with Ca²⁺-sensitive dye demonstrates that (-)-PCB 136 but not (+)-PCB 136 increases the frequency of spontaneous Ca²⁺ oscillations. Similarly, (-)-PCB 136 but not (+)-PCB 136 increases the activity of hippocampal neurons plated on microelectrode arrays. These data support the hypothesis that atropselective effects on RyR activity translate into atropselective effects of PCB 136 atropisomers on neuronal connectivity, and suggest that the variable atropisomeric enrichment of chiral PCBs observed in the human population may be a significant determinant of individual susceptibility for adverse neurodevelopmental outcomes following PCB exposure.

  10. Does bladder outlet obstruction alter the non-neuronal cholinergic system of the human urothelium?

    Science.gov (United States)

    Bschleipfer, Thomas; Weidner, Wolfgang; Kummer, Wolfgang; Lips, Katrin S

    2012-11-27

    Alterations of the bladder sensory system are considered to contribute to detrusor overactivity (DO) when patients suffer from bladder outlet obstruction (BOO). The urothelium is one part of this sensory system and it harbors a non-neuronal cholinergic system (NNCS). We aimed to investigate if BOO causes alterations in the NNCS. Urothelial specimens were collected by endoscopy from six male controls and eight male patients suffering from BOO and DO. The samples were examined by immunofluorescence (IF) and real-time RT-PCR for high-affinity choline transporter-1 (CHT1), choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT), organic cation transporters OCT1-3, muscarinic receptor (mAChR) subtypes M1-M5 and nicotinic receptor (nAChR) subunits α7, α9 and α10. ChAT, VAChT and OCT2 are not present in the male urothelium. Real-time RT-PCR and IF detected all other investigated targets. Rank order of expression was M2≫M3=M5>M4=M1 for mAChR subtypes and α7≫α10>α9 for nAChR subunits. Statistical analysis of RT-PCR results did not detect significant differences between patients and controls. Only IF detected differences between both groups: α9-Immunolabeling was increased in all BOO/DO patients. BOO does not induce considerable alterations of the human urothelial NNCS on mRNA level. Expression of mAChRs, CHT1, OCT1 and OCT3 is not significantly affected by BOO. Thus, transport mechanisms for choline and acetylcholine (ACh) stay unaltered. BOO increases immunolabeling of α9-nAChR but whether this sole finding contributes to the onset of DO seems questionable. Comparing the present results with our previous work, the urothelial NNCS does not differ between men and women. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Trim9 Deletion Alters the Morphogenesis of Developing and Adult-Born Hippocampal Neurons and Impairs Spatial Learning and Memory.

    Science.gov (United States)

    Winkle, Cortney C; Olsen, Reid H J; Kim, Hyojin; Moy, Sheryl S; Song, Juan; Gupton, Stephanie L

    2016-05-04

    During hippocampal development, newly born neurons migrate to appropriate destinations, extend axons, and ramify dendritic arbors to establish functional circuitry. These developmental stages are recapitulated in the dentate gyrus of the adult hippocampus, where neurons are continuously generated and subsequently incorporate into existing, local circuitry. Here we demonstrate that the E3 ubiquitin ligase TRIM9 regulates these developmental stages in embryonic and adult-born mouse hippocampal neurons in vitro and in vivo Embryonic hippocampal and adult-born dentate granule neurons lacking Trim9 exhibit several morphological defects, including excessive dendritic arborization. Although gross anatomy of the hippocampus was not detectably altered by Trim9 deletion, a significant number of Trim9(-/-) adult-born dentate neurons localized inappropriately. These morphological and localization defects of hippocampal neurons in Trim9(-/-) mice were associated with extreme deficits in spatial learning and memory, suggesting that TRIM9-directed neuronal morphogenesis may be involved in hippocampal-dependent behaviors. Appropriate generation and incorporation of adult-born neurons in the dentate gyrus are critical for spatial learning and memory and other hippocampal functions. Here we identify the brain-enriched E3 ubiquitin ligase TRIM9 as a novel regulator of embryonic and adult hippocampal neuron shape acquisition and hippocampal-dependent behaviors. Genetic deletion of Trim9 elevated dendritic arborization of hippocampal neurons in vitro and in vivo Adult-born dentate granule cells lacking Trim9 similarly exhibited excessive dendritic arborization and mislocalization of cell bodies in vivo These cellular defects were associated with severe deficits in spatial learning and memory. Copyright © 2016 the authors 0270-6474/16/364940-19$15.00/0.

  12. Levetiracetam differentially alters CD95 expression of neuronal cells and the mitochondrial membrane potential of immune and neuronal cells in vitro

    Directory of Open Access Journals (Sweden)

    Susannah K Rogers

    2014-02-01

    Full Text Available Epilepsy is a neurological seizure disorder that affects over 100 million people worldwide. Levetiracetam, either alone, as monotherapy, or as adjunctive treatment, is widely used to control certain types of seizures. Despite its increasing popularity as a relatively safe and effective anti-convulsive treatment option, its mechanism(s of action are poorly understood. Studies have suggested neuronal, glial, and immune mechanisms of action. Understanding the precise mechanisms of action of Levetiracetam would be extremely beneficial in helping to understand the processes involved in seizure generation and epilepsy. Moreover, a full understanding of these mechanisms would help to create more efficacious treatments while minimizing side effects. The current study examined the effects of Levetiracetam on the mitochondrial membrane potential of neuronal and non-neuronal cells, in vitro, in order to determine if Levetiracetam influences metabolic processes in these cell types. In addition, this study sought to address possible immune-mediated mechanisms by determining if Levetiracetam alters the expression of immune receptor-ligand pairs. The results show that Levetiracetam induces expression of CD95 and CD178 on NGF-treated C17.2 neuronal cells. The results also show that Levetiracetam increases mitochondrial membrane potential on C17.2 neuronal cells in the presence of nerve growth factor. In contrast, Levetiracetam decreases the mitochondrial membrane potential of splenocytes and this effect was dependent on intact invariant chain, thus implicating immune cell interactions. These results suggest that both neuronal and non-neuronal anti-epileptic activities of Levetiracetam involve control over energy metabolism, more specifically, mΔΨ. Future studies are needed to further investigate this potential mechanism of action.

  13. Aluminum alters NMDA receptor 1A and 2A/B expression on neonatal hippocampal neurons in rats

    Directory of Open Access Journals (Sweden)

    Yuan Chia-Yi

    2011-11-01

    Full Text Available Abstract Background High aluminum (Al content in certain infant formula raises the concern of possible Al toxicity on brain development of neonates during their vulnerable period of growing. Results of in vivo study showed that Al content of brain tissues reached to 74 μM when oral intake up to 1110 μM, 10 times of that in the hi-Al infant formula. Methods Utilizing a cultured neuron cells in vitro model, we have assessed Al influence on neuronal specific gene expression alteration by immunoblot and immunohistochemistry and neural proliferation rate changes by MTT assay. Results Microscopic images showed that the neurite outgrowth of hippocampal neurons increased along with the Al dosages (37, 74 μM Al (AlCl3. MTT results also indicated that Al increased neural cell viability. On the other hand, the immunocytochemistry staining suggested that the protein expressions of NMDAR 1A and NMDAR 2A/B decreased with the Al dosages (p Conclusion Treated hippocampal neurons with 37 and 74 μM of Al for 14 days increased neural cell viability, but hampered NMDAR 1A and NMDAR 2A/B expressions. It was suggested that Al exposure might alter the development of hippocampal neurons in neonatal rats.

  14. Distinctive transcriptome alterations of prefrontal pyramidal neurons in schizophrenia and schizoaffective disorder.

    Science.gov (United States)

    Arion, D; Corradi, J P; Tang, S; Datta, D; Boothe, F; He, A; Cacace, A M; Zaczek, R; Albright, C F; Tseng, G; Lewis, D A

    2015-11-01

    Schizophrenia is associated with alterations in working memory that reflect dysfunction of dorsolateral prefrontal cortex (DLPFC) circuitry. Working memory depends on the activity of excitatory pyramidal cells in DLPFC layer 3 and, to a lesser extent, in layer 5. Although many studies have profiled gene expression in DLPFC gray matter in schizophrenia, little is known about cell-type-specific transcript expression in these two populations of pyramidal cells. We hypothesized that interrogating gene expression, specifically in DLPFC layer 3 or 5 pyramidal cells, would reveal new and/or more robust schizophrenia-associated differences that would provide new insights into the nature of pyramidal cell dysfunction in the illness. We also sought to determine the impact of other variables, such as a diagnosis of schizoaffective disorder or medication use at the time of death, on the patterns of gene expression in pyramidal neurons. Individual pyramidal cells in DLPFC layers 3 or 5 were captured by laser microdissection from 36 subjects with schizophrenia or schizoaffective disorder and matched normal comparison subjects. The mRNA from cell collections was subjected to transcriptome profiling by microarray followed by quantitative PCR validation. Expression of genes involved in mitochondrial (MT) or ubiquitin-proteasome system (UPS) functions were markedly downregulated in the patient group (P-values for MT-related and UPS-related pathways were schizoaffective disorder subjects (diagnosis of schizoaffective disorder was the most significant covariate, Pschizoaffective disorder, providing a potential molecular-cellular basis of differences in clinical phenotypes.

  15. Short-term enrichment makes male rats more attractive, more defensive and alters hypothalamic neurons.

    Directory of Open Access Journals (Sweden)

    Rupshi Mitra

    Full Text Available Innate behaviors are shaped by contingencies built during evolutionary history. On the other hand, environmental stimuli play a significant role in shaping behavior. In particular, a short period of environmental enrichment can enhance cognitive behavior, modify effects of stress on learned behaviors and induce brain plasticity. It is unclear if modulation by environment can extend to innate behaviors which are preserved by intense selection pressure. In the present report we investigate this issue by studying effects of relatively short (14-days environmental enrichment on two prominent innate behaviors in rats, avoidance of predator odors and ability of males to attract mates. We show that enrichment has strong effects on both the innate behaviors: a enriched males were more avoidant of a predator odor than non-enriched controls, and had a greater rise in corticosterone levels in response to the odor; and b had higher testosterone levels and were more attractive to females. Additionally, we demonstrate decrease in dendritic length of neurons of ventrolateral nucleus of hypothalamus, important for reproductive mate-choice and increase in the same in dorsomedial nucleus, important for defensive behavior. Thus, behavioral and hormonal observations provide evidence that a short period of environmental manipulation can alter innate behaviors, providing a good example of gene-environment interaction.

  16. (R1441C) LRRK2 induces the degeneration of SN dopaminergic neurons and alters the expression of genes regulating neuronal survival in a transgenic mouse model.

    Science.gov (United States)

    Weng, Yi-Hsin; Chen, Chu-Yu; Lin, Kun-Jun; Chen, Ying-Ling; Yeh, Tu-Hsueh; Hsiao, Ing-Tsung; Chen, Ing-Jou; Lu, Chin-Song; Wang, Hung-Li

    2016-01-01

    Mutation of leucine-rich repeat kinase 2 (LRRK2) is the most common genetic cause of both familial and sporadic Parkinson's disease (PD) cases. Several mutations in LRRK2 gene were reported in PD patients. R1441 is the second most frequent site of LRRK2 mutation. We generated (R1441C) LRRK2 transgenic mice that displayed motor deficits at the age of 16 months. Compared with wild-type mice, 16-month-old (R1441C) LRRK2 mice exhibited a significant reduction in the number of substantia nigra (SN) dopaminergic neurons. To elucidate molecular pathogenic pathways involved in (R1441C) LRRK2-induced death of SN dopaminergic neurons, we performed microarray analysis to visualize altered mRNA expressions in the SN of (R1441C) LRRK2 mouse. In the SN of (R1441C) LRRK2 transgenic mouse, the mRNA expression of three genes that promote cell death was upregulated, while the mRNA expression of seven genes that contribute to neurogenesis/neuroprotection was significantly downregulated. Our results suggest that altered expression of these genes involved in regulating neuronal survival may contribute to the pathogenesis of (R1441C) LRRK2-induced PD. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Cytomorphometric changes in the dorsal raphe neurons after rapid eye movement sleep deprivation are mediated by noradrenalin in rats

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    Biswas Sudipta

    2010-10-01

    Full Text Available Abstract Objectives This study was carried out to investigate the effect of rapid eye movement sleep (REMS deprivation (REMSD on the cytomorphology of the dorsal raphe (DR neurons and to evaluate the possible role of REMSD-induced increased noradrenalin (NA in mediating such effects. Methods Rats were REMS deprived by the flowerpot method; free moving normal home cage rats, large platform and post REMS-deprived recovered rats were used as controls. Further, to evaluate if the effects were induced by NA, separate sets of experimental rats were treated (i.p. with α1-adrenoceptor antagonist, prazosin (PRZ. Histomorphometric analysis of DR neurons in stained brain sections were performed in experimental and control rats; neurons in inferior colliculus (IC served as anatomical control. Results The mean size of DR neurons was larger in REMSD group compared to controls, whereas, neurons in the recovered group of rats did not significantly differ than those in the control animals. Further, mean cell size in the post-REMSD PRZ-treated animals was comparable to those in the control groups. IC neurons were not affected by REMSD. Conclusions REMS loss has been reported to impair several physiological, behavioral and cellular processes. The mean size of the DR neurons was larger in the REMS deprived group of rats than those in the control groups; however, in the REMS deprived and prazosin treated rats the size was comparable to the normal rats. These results showed that REMSD induced increase in DR neuronal size was mediated by NA acting on α1-adrenoceptor. The findings suggest that the sizes of DR neurons are sensitive to REMSD, which if not compensated could lead to neurodegeneration and associated disorders including memory loss and Alzheimer's disease.

  18. The Alteration of Neonatal Raphe Neurons by Prenatal-Perinatal Nicotine. Meaning for Sudden Infant Death Syndrome.

    Science.gov (United States)

    Cerpa, Verónica J; Aylwin, María de la Luz O; Beltrán-Castillo, Sebastián; Bravo, Eduardo U; Llona, Isabel R; Richerson, George B; Eugenín, Jaime L

    2015-10-01

    Nicotine may link maternal cigarette smoking with respiratory dysfunctions in sudden infant death syndrome (SIDS). Prenatal-perinatal nicotine exposure blunts ventilatory responses to hypercapnia and reduces central respiratory chemoreception in mouse neonates at Postnatal Days 0 (P0) to P3. This suggests that raphe neurons, which are altered in SIDS and contribute to central respiratory chemoreception, may be affected by nicotine. We therefore investigated whether prenatal-perinatal nicotine exposure affects the activity, electrical properties, and chemosensitivity of raphe obscurus (ROb) neurons in mouse neonates. Osmotic minipumps, implanted subcutaneously in 5- to 7-day-pregnant CF1 mice, delivered nicotine bitartrate (60 mg kg(-1) d(-1)) or saline (control) for up to 28 days. In neonates, ventilation was recorded by head-out plethysmography, c-Fos (neuronal activity marker), or serotonin autoreceptors (5HT1AR) were immunodetected using light microscopy, and patch-clamp recordings were made from raphe neurons in brainstem slices under normocarbia and hypercarbia. Prenatal-perinatal nicotine exposure decreased the hypercarbia-induced ventilatory responses at P1-P5, reduced both the number of c-Fos-positive ROb neurons during eucapnic normoxia at P1-P3 and their hypercapnia-induced recruitment at P3, increased 5HT1AR immunolabeling of ROb neurons at P3-P5, and reduced the spontaneous firing frequency of ROb neurons at P3 without affecting their CO2 sensitivity or their passive and active electrical properties. These findings reveal that prenatal-perinatal nicotine reduces the activity of neonatal ROb neurons, likely as a consequence of increased expression of 5HT1ARs. This hypoactivity may change the functional state of the respiratory neural network leading to breathing vulnerability and chemosensory failure as seen in SIDS.

  19. Enhanced excitability of primary sensory neurons and altered gene expression of neuronal ion channels in dorsal root ganglion in paclitaxel-induced peripheral neuropathy.

    Science.gov (United States)

    Zhang, Haijun; Dougherty, Patrick M

    2014-06-01

    The mechanism of chemotherapy-induced peripheral neuropathy after paclitaxel treatment is not well understood. Given the poor penetration of paclitaxel into central nervous system, peripheral nervous system is most at risk. Intrinsic membrane properties of dorsal root ganglion neurons were studied by intracellular recordings. Multiple-gene real-time polymerase chain reaction array was used to investigate gene expression of dorsal root ganglion neuronal ion channels. Paclitaxel increased the incidence of spontaneous activity from 4.8 to 27.1% in large-sized and from 0 to 33.3% in medium-sized neurons. Paclitaxel decreased the rheobase (nA) from 1.6 ± 0.1 to 0.8 ± 0.1 in large-sized, from 1.5 ± 0.2 to 0.6 ± 0.1 in medium-sized, and from 1.6 ± 0.2 to 1.0 ± 0.1 in small-sized neurons. After paclitaxel treatment, other characteristics of membrane properties in each group remained the same except that Aδ neurons showed shorter action potential fall time (ms) (1.0 ± 0.2, n = 10 vs. 1.8 ± 0.3, n = 9, paclitaxel vs. vehicle). Meanwhile, real-time polymerase chain reaction array revealed an alteration in expression of some neuronal ion channel genes including up-regulation of hyperpolarization-activated cyclic nucleotide-gated channel 1 (fold change 1.76 ± 0.06) and Nav1.7 (1.26 ± 0.02) and down-regulation of Kir channels (Kir1.1, 0.73 ± 0.05, Kir3.4, 0.66 ± 0.06) in paclitaxel-treated animals. The increased neuronal excitability and the changes in gene expression of some neuronal ion channels in dorsal root ganglion may provide insight into the molecular and cellular basis of paclitaxel-induced neuropathy, which may lead to novel therapeutic strategies.

  20. Complementary processing of haptic information by slowly and rapidly adapting neurons in the trigeminothalamic pathway. Electrophysiology, mathematical modeling and simulations of vibrissae-related neurons.

    Directory of Open Access Journals (Sweden)

    Abel eSanchez-Jimenez

    2013-06-01

    Full Text Available Tonic (slowly adapting and phasic (rapidly adapting primary afferents convey complementary aspects of haptic information to the central nervous system: object location and texture the former, shape the latter. Tonic and phasic neural responses are also recorded in all relay stations of the somatosensory pathway, yet it is unknown their role in both, information processing and information transmission to the cortex: we don’t know if tonic and phasic neurons process complementary aspects of haptic information and/or if these two types constitute two separate channels that convey complementary aspects of tactile information to the cortex. Here we propose to elucidate these two questions in the fast trigeminal pathway of the rat (PrV-VPM: principal trigeminal nucleus-ventroposteromedial thalamic nucleus. We analyze early and global behavior, latencies and stability of the responses of individual cells in PrV and medial lemniscus under 1-40 Hz stimulation of the whiskers in control and decorticated animals and we use stochastic spiking models and extensive simulations. Our results strongly suggest that in the first relay station of the somatosensory system (PrV: 1 tonic and phasic neurons process complementary aspects of whisker-related tactile information 2 tonic and phasic responses are not originated from two different types of neurons 3 the two responses are generated by the differential action of the somatosensory cortex on a unique type of PrV cell 4 tonic and phasic neurons do not belong to two different channels for the transmission of tactile information to the thalamus 5 trigeminothalamic transmission is exclusively performed by tonically firing neurons and 6 all aspects of haptic information are coded into low-pass, band-pass and high-pass filtering profiles of tonically firing neurons. Our results are important for both, basic research on neural circuits and information processing, and development of sensory neuroprostheses.

  1. Immune clearance of attenuated rabies virus results in neuronal survival with altered gene expression.

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    Emily A Gomme

    Full Text Available Rabies virus (RABV is a highly neurotropic pathogen that typically leads to mortality of infected animals and humans. The precise etiology of rabies neuropathogenesis is unknown, though it is hypothesized to be due either to neuronal death or dysfunction. Analysis of human brains post-mortem reveals surprisingly little tissue damage and neuropathology considering the dramatic clinical symptomology, supporting the neuronal dysfunction model. However, whether or not neurons survive infection and clearance and, provided they do, whether they are functionally restored to their pre-infection phenotype has not been determined in vivo for RABV, or any neurotropic virus. This is due, in part, to the absence of a permanent "mark" on once-infected cells that allow their identification long after viral clearance. Our approach to study the survival and integrity of RABV-infected neurons was to infect Cre reporter mice with recombinant RABV expressing Cre-recombinase (RABV-Cre to switch neurons constitutively expressing tdTomato (red to expression of a Cre-inducible EGFP (green, permanently marking neurons that had been infected in vivo. We used fluorescence microscopy and quantitative real-time PCR to measure the survival of neurons after viral clearance; we found that the vast majority of RABV-infected neurons survive both infection and immunological clearance. We were able to isolate these previously infected neurons by flow cytometry and assay their gene expression profiles compared to uninfected cells. We observed transcriptional changes in these "cured" neurons, predictive of decreased neurite growth and dysregulated microtubule dynamics. This suggests that viral clearance, though allowing for survival of neurons, may not restore them to their pre-infection functionality. Our data provide a proof-of-principle foundation to re-evaluate the etiology of human central nervous system diseases of unknown etiology: viruses may trigger permanent neuronal

  2. Vasoactive intestinal polypeptide excites medial pontine reticular formation neurons in the brainstem rapid eye movement sleep-induction zone

    DEFF Research Database (Denmark)

    Kohlmeier, Kristi Anne; Reiner, P B

    1999-01-01

    Although it has long been known that microinjection of the cholinergic agonist carbachol into the medial pontine reticular formation (mPRF) induces a state that resembles rapid eye movement (REM) sleep, it is likely that other transmitters contribute to mPRF regulation of behavioral states. A key...... conclude that VIP excites mPRF neurons by activation of a sodium current. This effect is mediated at least in part by G-protein stimulation of adenylyl cyclase, cAMP, and protein kinase A. These data suggest that VIP may play a physiological role in REM induction by its actions on mPRF neurons....

  3. In Vitro Research of the Alteration of Neurons in Vagal Core in Medulla Oblongata at Asphyxic Deaths

    Directory of Open Access Journals (Sweden)

    Naim Haliti

    2010-08-01

    Full Text Available The aim of this study was to research the morphological changes of neurons in the vagus nerve nuclei in medulla oblongata in asphyxia related death cases. Morphological changes that were investigated were mainly in the dorsal motor respiratory center (DMRC, nucleus tractus solitarius (nTS and nucleus ambigus (nA in the medulla oblongata. In our research, the autopsy material from asphyxia related death cases was used from various etiologies: monoxide carbon (CO, liquid drowning, strangulation, electricity, clinical-pathological death, firing weapon, explosive weapon, sharp and blunt objects and death cases due to accident. The material selected for research was taken from medulla oblongata and lungs from all lobes. The material from the medulla oblongata and lungs was fixed in a 10% solution of buffered formalin. Special histochemical methods for central nervous system (CNS were employed like: Cresyl echt violet, toluidin blue, Sevier-Munger modification and Grimelius. For stereometrical analysis of the quantitative density of the neurons the universal testing system Weibel M42 was used. The acquired results show that in sudden asphyxia related death cases, there are alterations in the nuclei of vagal nerve in form of: central chromatolysis, axonal retraction, axonal fragmentation, intranuclear vacuolization, cytoplasmic vacuolization, edema, condensation and dispersion of substance of Nissl, proliferation of oligodendrocytes, astrocytes and microglia. The altered population of vagus nerve neurons does not show an important statistica! significarne compared to the overall quantity of the neurons in the nuclei of the vagus nerve (p<0,05.

  4. Nutritional n-3 PUFAs deficiency during perinatal periods alters brain innate immune system and neuronal plasticity-associated genes.

    Science.gov (United States)

    Madore, Charlotte; Nadjar, Agnès; Delpech, Jean-Christophe; Sere, A; Aubert, A; Portal, Céline; Joffre, Corinne; Layé, Sophie

    2014-10-01

    Low dietary intake of the n-3 polyunsaturated fatty acids (PUFAs) is a causative factor of neurodevelopmental disorders. However the mechanisms linking n-3 PUFAs low dietary intake and neurodevelopmental disorders are poorly understood. Microglia, known mainly for their immune function in the injured or infected brain, have recently been demonstrated to play a pivotal role in regulating maturation of neuronal circuits during normal brain development. Disruption of this role during the perinatal period therefore could significantly contribute to psychopathologies with a neurodevelopmental neurodevelopmental component. N-3 PUFAs, essential lipids and key structural components of neuronal membrane phospholipids, are highly incorporated in cell membranes during the gestation and lactation phase. We previously showed that in a context of perinatal n-3 PUFAs deficiency, accretion of these latter is decreased and this is correlated to an alteration of endotoxin-induced inflammatory response. We thus postulated that dietary n-3 PUFAs imbalance alters the activity of microglia in the developing brain, leading to abnormal formation of neuronal networks. We first confirmed that mice fed with a n-3 PUFAs deficient diet displayed decreased n-3 PUFAs levels in the brain at post-natal days (PND)0 and PND21. We then demonstrated that n-3 PUFAs deficiency altered microglia phenotype and motility in the post-natal developing brain. This was paralleled by an increase in pro-inflammatory cytokines expression at PND21 and to modification of neuronal plasticity-related genes expression. Overall, our findings show for the first time that a dietary n-3 PUFAs deficiency from the first day of gestation leads to the development of a pro-inflammatory condition in the central nervous system that may contribute to neurodevelopmental alterations. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Functional alterations of the ubiquitin-proteasome system in motor neurons of a mouse model of familial amyotrophic lateral sclerosis†

    OpenAIRE

    Cheroni, Cristina; Marino, Marianna; Tortarolo, Massimo; Veglianese, Pietro; De Biasi, Silvia; Fontana, Elena; Zuccarello, Laura Vitellaro; Maynard, Christa J.; Dantuma, Nico P; Bendotti, Caterina

    2008-01-01

    In familial and sporadic amyotrophic lateral sclerosis (ALS) and in rodent models of the disease, alterations in the ubiquitin-proteasome system (UPS) may be responsible for the accumulation of potentially harmful ubiquitinated proteins, leading to motor neuron death. In the spinal cord of transgenic mice expressing the familial ALS superoxide dismutase 1 (SOD1) gene mutation G93A (SOD1G93A), we found a decrease in constitutive proteasome subunits during disease progression, as assessed by re...

  6. Suppression of Radixin and Moesin Alters Growth Cone Morphology, Motility, and Process Formation In Primary Cultured Neurons

    Science.gov (United States)

    Paglini, Gabriela; Kunda, Patricia; Quiroga, Santiago; Kosik, Kenneth; Cáceres, Alfredo

    1998-01-01

    In this study we have examined the cellular functions of ERM proteins in developing neurons. The results obtained indicate that there is a high degree of spatial and temporal correlation between the expression and subcellular localization of radixin and moesin with the morphological development of neuritic growth cones. More importantly, we show that double suppression of radixin and moesin, but not of ezrin–radixin or ezrin–moesin, results in reduction of growth cone size, disappearance of radial striations, retraction of the growth cone lamellipodial veil, and disorganization of actin filaments that invade the central region of growth cones where they colocalize with microtubules. Neuritic tips from radixin–moesin suppressed neurons displayed high filopodial protrusive activity; however, its rate of advance is 8–10 times slower than the one of growth cones from control neurons. Radixin–moesin suppressed neurons have short neurites and failed to develop an axon-like neurite, a phenomenon that appears to be directly linked with the alterations in growth cone structure and motility. Taken collectively, our data suggest that by regulating key aspects of growth cone development and maintenance, radixin and moesin modulate neurite formation and the development of neuronal polarity. PMID:9786954

  7. Antipsychotic drugs alter neuronal development including ALM neuroblast migration and PLM axonal outgrowth in Caenorhabditis elegans.

    Science.gov (United States)

    Donohoe, Dallas R; Weeks, Kathrine; Aamodt, Eric J; Dwyer, Donard S

    2008-01-01

    Antipsychotic drugs are increasingly being prescribed for children and adolescents, and are used in pregnant women without a clear demonstration of safety in these populations. Global effects of these drugs on neurodevelopment (e.g., decreased brain size) have been reported in rats, but detailed knowledge about neuronal effects and mechanisms of action are lacking. Here we report on the evaluation of a comprehensive panel of antipsychotic drugs in a model organism (Caenorhabditis elegans) that is widely used to study neuronal development. Specifically, we examined the effects of the drugs on neuronal migration and axonal outgrowth in mechanosensory neurons visualized with green fluorescent protein expressed from the mec-3 promoter. Clozapine, fluphenazine, and haloperidol produced deficits in the development and migration of ALM neurons and axonal outgrowth in PLM neurons. The defects included failure of neuroblasts to migrate to the proper location, and excessive growth of axons past their normal termination point, together with abnormal morphological features of the processes. Although the antipsychotic drugs are potent antagonists of dopamine and serotonin receptors, the neurodevelopmental deficits were not rescued by co-incubation with serotonin or the dopaminergic agonist, quinpirole. Other antipsychotic drugs, risperidone, aripiprazole, quetiapine, trifluoperazine and olanzapine, also produced modest, but detectable, effects on neuronal development. This is the first report that antipsychotic drugs interfere with neuronal migration and axonal outgrowth in a developing nervous system.

  8. Rett syndrome induced pluripotent stem cell-derived neurons reveal novel neurophysiological alterations.

    Science.gov (United States)

    Farra, N; Zhang, W-B; Pasceri, P; Eubanks, J H; Salter, M W; Ellis, J

    2012-12-01

    Rett syndrome (RTT) is a neurodevelopmental autism spectrum disorder caused by mutations in the methyl-CpG-binding protein 2 (MECP2) gene. Here, we describe the first characterization and neuronal differentiation of induced pluripotent stem (iPS) cells derived from Mecp2-deficient mice. Fully reprogrammed wild-type (WT) and heterozygous female iPS cells express endogenous pluripotency markers, reactivate the X-chromosome and differentiate into the three germ layers. We directed iPS cells to produce glutamatergic neurons, which generated action potentials and formed functional excitatory synapses. iPS cell-derived neurons from heterozygous Mecp2(308) mice showed defects in the generation of evoked action potentials and glutamatergic synaptic transmission, as previously reported in brain slices. Further, we examined electrophysiology features not yet studied with the RTT iPS cell system and discovered that MeCP2-deficient neurons fired fewer action potentials, and displayed decreased action potential amplitude, diminished peak inward currents and higher input resistance relative to WT iPS-derived neurons. Deficiencies in action potential firing and inward currents suggest that disturbed Na(+) channel function may contribute to the dysfunctional RTT neuronal network. These phenotypes were additionally confirmed in neurons derived from independent WT and hemizygous mutant iPS cell lines, indicating that these reproducible deficits are attributable to MeCP2 deficiency. Taken together, these results demonstrate that neuronally differentiated MeCP2-deficient iPS cells recapitulate deficits observed previously in primary neurons, and these identified phenotypes further illustrate the requirement of MeCP2 in neuronal development and/or in the maintenance of normal function. By validating the use of iPS cells to delineate mechanisms underlying RTT pathogenesis, we identify deficiencies that can be targeted for in vitro translational screens.

  9. Neonatal exposure to sucralose does not alter biochemical markers of neuronal development or adult behavior.

    Science.gov (United States)

    Viberg, Henrik; Fredriksson, Anders

    2011-01-01

    Sucralose, a high-intensity sweetener, has been approved as a general-purpose sweetener in all food since the late 1990s. Due to its good taste and physiochemical profile, its use has increased and sucralose is considered a way of managing health and an option to improve the quality of life in the diabetic population. Recently high concentrations of sucralose have been found in the environment. Other environmental pollutants have been shown to induce neurotoxic effects when administered during a period of rapid brain growth and development. This period of rapid brain growth and development is postnatal in mice and rats, spanning the first 3-4 wk of life, reaching its peak around postnatal day 10, whereas in humans, brain growth and development is perinatal. The proteins calcium/calmodulin-dependent protein kinase II, growth-associated protein-43, synaptophysin, and tau play important roles during brain growth and development. In the present study, mice were orally exposed to 5-125 mg of sucralose per kilogram of body weight per day during postnatal days 8-12. Twenty-four hours after last exposure, brains were analyzed for calcium/calmodulin-dependent protein kinase II, growth-associated protein-43, synaptophysin, and tau, and at the age of 2 mo the animals were tested for spontaneous behavior. The protein analysis showed no alterations in calcium/calmodulin-dependent protein kinase II, growth-associated protein-43, synaptophysin, or tau. Furthermore, there were no disturbances in adult behavior or habituation after neonatal sucralose exposure. The present study shows that repeated neonatal exposure to the artificial sweetener sucralose does not result in neurotoxicity, which supports that sucralose seems to be a safe alternative for people who want or need to reduce or substitute glucose in their diet. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Altered neuronal firing pattern of the basal ganglia nucleus plays a role in levodopa-induced dyskinesia in patients with Parkinson's disease

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    Xiaoyu eLi

    2015-11-01

    Full Text Available Background: Levodopa therapy alleviates the symptoms of Parkinson's disease (PD, but long-term treatment often leads to motor complications such as levodopa-induced dyskinesia (LID. Aim: To explore the neuronal activity in the basal ganglia nuclei in patients with PD and LID. Methods: Thirty patients with idiopathic PD (age, 55.1±11.0 years; disease duration, 8.7±5.6 years were enrolled between August 2006 and August 2013 at the Xuanwu Hospital, Capital Medical University, China. Their Hoehn and Yahr scores ranged from 2 to 4 and their UPDRS III scores were 28.5±5.2. Fifteen of them had severe LID (UPDRS IV scores of 6.7±1.6. Microelectrode recording was performed in the globus pallidus internus (GPi and subthalamic nucleus (STN during pallidotomy (n=12 or STN deep brain stimulation (DBS; bilateral, n=12; unilateral, n=6. The firing patterns and frequencies of various cell types were analyzed by assessing single cell interspike intervals (ISIs and the corresponding coefficient of variation (CV. Results: A total of 295 neurons were identified from the GPi (n=12 and STN (n=18. These included 26 (8.8% highly grouped discharge, 30 (10.2% low frequency firing, 78 (26.4% rapid tonic discharge, 103 (34.9% irregular activity, and 58 (19.7% tremor-related activity. There were significant differences between the two groups (P<0.05 for neurons with irregular firing, highly irregular cluster-like firing, and low-frequency firing. Conclusion: Altered neuronal activity was observed in the basal ganglia nucleus of GPi and STN, and may play important roles in the pathophysiology of PD and LID.

  11. Altered biometal homeostasis is associated with CLN6 mRNA loss in mouse neuronal ceroid lipofuscinosis

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    Katja M. Kanninen

    2013-05-01

    Neuronal ceroid lipofuscinoses, the most common fatal childhood neurodegenerative illnesses, share many features with more prevalent neurodegenerative diseases. Neuronal ceroid lipofuscinoses are caused by mutations in CLN genes. CLN6 encodes a transmembrane endoplasmic reticulum protein with no known function. We characterized the behavioural phenotype of spontaneous mutant mice modeling CLN6 disease, and demonstrate progressive motor and visual decline and reduced lifespan in these mice, consistent with symptoms observed in neuronal ceroid lipofuscinosis patients. Alterations to biometal homeostasis are known to play a critical role in pathology in Alzheimer's, Parkinson's, Huntington's and motor neuron diseases. We have previously shown accumulation of the biometals, zinc, copper, manganese and cobalt, in CLN6 Merino and South Hampshire sheep at the age of symptom onset. Here we determine the physiological and disease-associated expression of CLN6, demonstrating regional CLN6 transcript loss, and concurrent accumulation of the same biometals in the CNS and the heart of presymptomatic CLN6 mice. Furthermore, increased expression of the ER/Golgi-localized cation transporter protein, Zip7, was detected in cerebellar Purkinje cells and whole brain fractions. Purkinje cells not only control motor function, an early symptomatic change in the CLN6 mice, but also display prominent neuropathological changes in mouse models and patients with different forms of neuronal ceroid lipofuscinoses. Whole brain fractionation analysis revealed biometal accumulation in fractions expressing markers for ER, Golgi, endosomes and lysosomes of CLN6 brains. These data are consistent with a link between CLN6 expression and biometal homeostasis in CLN6 disease, and provide further support for altered cation transporter regulation as a key factor in neurodegeneration.

  12. Vector-averaged gravity alters myocyte and neuron properties in cell culture

    Science.gov (United States)

    Gruener, Raphael; Hoeger, Glenn

    1991-01-01

    The effect of changes in the gravitational field of developing neurons and myocytes on the development of these cells was investigated using observations of rotated cultures of embryonic spinal neurons and myocytes in a horizontal clinostat, in which rotation produces, from the cells' perspective, a 'vector-free' gravity environment by continous averaging of the vector, thus simulating the microgravity of space. It was found that, at rotation rates between 1 and 50 rpm, cellular and nuclear areas of myocytes become significantly enlarged and the number of presumptive nucleoli increase; in neurons, frequent and large swellings appeared along neuritic shafts. Some of these changes were reversible after the cessation of rotation.

  13. Acute pressure on the sciatic nerve results in rapid inhibition of the wide dynamic range neuronal response

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    Wang Wenxue

    2012-12-01

    Full Text Available Abstract Background Acute pressure on the sciatic nerve has recently been reported to provide rapid short-term relief of pain in patients with various pathologies. Wide dynamic range (WDR neurons transmit nociceptive information from the dorsal horn to higher brain centers. In the present study, we examined the effect of a 2-min application of sciatic nerve pressure on WDR neuronal activity in anesthetized male Sprague–Dawley rats. Results Experiments were carried out on 41 male Sprague–Dawley albino rats weighing 160–280 grams. Dorsal horn WDR neurons were identified on the basis of characteristic responses to mechanical stimuli applied to the cutaneous receptive field. Acute pressure was applied for 2 min to the sciatic nerve using a small vascular clip. The responses of WDR neurons to three mechanical stimuli applied to the cutaneous receptive field were recorded before, and 2, 5 and 20 min after cessation of the 2-min pressure application on the sciatic nerve. Two-min pressure applied to the sciatic nerve caused rapid attenuation of the WDR response to pinching, pressure and brushing stimuli applied to the cutaneous receptive field. Maximal attenuation of the WDR response to pinching and pressure was noted 5 min after release of the 2-min pressure on the sciatic nerve. The mean firing rate decreased from 31.7±1.7 Hz to 13±1.4 Hz upon pinching (p p p Conclusions Our results indicate that acute pressure applied to the sciatic nerve exerts a rapid inhibitory effect on the WDR response to both noxious and innocuous stimuli. Our results may partially explain the rapid analgesic effect of acute sciatic nerve pressure noted in clinical studies, and also suggest a new model for the study of pain.

  14. Altered Chloride Homeostasis Decreases the Action Potential Threshold and Increases Hyperexcitability in Hippocampal Neurons

    DEFF Research Database (Denmark)

    Sørensen, Andreas T; Ledri, Marco; Melis, Miriam

    2017-01-01

    flows through activated GABAA receptors into the neurons causing hyperpolarization or shunting inhibition, and in turn inhibits action potential (AP) generation. However, in situations when intracellular chloride concentration is increased, chloride ions can flow in opposite direction, depolarize...

  15. Membrane potential depolarization causes alterations in neuron arrangement and connectivity in cocultures

    OpenAIRE

    ?zkucur, Nurdan; Quinn, Kyle P.; Pang, Jin C; Du, Chuang; Georgakoudi, Irene; Miller, Eric; Levin, Michael; Kaplan, David L.

    2014-01-01

    Background The disruption of neuron arrangement is associated with several pathologies. In contrast to action potentials, the role of resting potential (Vmem) in regulating connectivity remains unknown. Methods Neuron assemblies were quantified when their Vmem was depolarized using ivermectin (Ivm), a drug that opens chloride channels, for 24?h in cocultures with astrocytes. Cell aggregation was analyzed using automated cluster analysis methods. Neural connectivity was quantified based on the...

  16. Exposure to extremely low frequency electromagnetic fields alters the calcium dynamics of cultured entorhinal cortex neurons.

    Science.gov (United States)

    Luo, Fen-Lan; Yang, Nian; He, Chao; Li, Hong-Li; Li, Chao; Chen, Fang; Xiong, Jia-Xiang; Hu, Zhi-An; Zhang, Jun

    2014-11-01

    Previous studies have revealed that extremely low frequency electromagnetic field (ELF-EMF) exposure affects neuronal dendritic spine density and NMDAR and AMPAR subunit expressions in the entorhinal cortex (EC). Although calcium signaling has a critical role in control of EC neuronal functions, however, it is still unclear whether the ELF-EMF exposure affects the EC neuronal calcium homeostasis. In the present study, using whole-cell recording and calcium imaging, we record the whole-cell inward currents that contain the voltage-gated calcium currents and show that ELF-EMF (50Hz, 1mT or 3mT, lasting 24h) exposure does not influence these currents. Next, we specifically isolate the high-voltage activated (HVA) and low-voltage activated (LVA) calcium channels-induced currents. Similarly, the activation and inactivation characteristics of these membrane calcium channels are also not influenced by ELF-EMF. Importantly, ELF-EMF exposure reduces the maximum amplitude of the high-K(+)-evoked calcium elevation in EC neurons, which is abolished by thapsigargin, a Ca(2+) ATPase inhibitor, to empty the intracellular calcium stores of EC neurons. Together, these findings indicate that ELF-EMF exposure specifically influences the intracellular calcium dynamics of cultural EC neurons via a calcium channel-independent mechanism. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Transgenic miR132 alters neuronal spine density and impairs novel object recognition memory.

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    Katelin F Hansen

    2010-11-01

    Full Text Available Inducible gene expression plays a central role in neuronal plasticity, learning, and memory, and dysfunction of the underlying molecular events can lead to severe neuronal disorders. In addition to coding transcripts (mRNAs, non-coding microRNAs (miRNAs appear to play a role in these processes. For instance, the CREB-regulated miRNA miR132 has been shown to affect neuronal structure in an activity-dependent manner, yet the details of its physiological effects and the behavioral consequences in vivo remain unclear. To examine these questions, we employed a transgenic mouse strain that expresses miR132 in forebrain neurons. Morphometric analysis of hippocampal neurons revealed that transgenic miR132 triggers a marked increase in dendritic spine density. Additionally, miR132 transgenic mice exhibited a decrease in the expression of MeCP2, a protein implicated in Rett Syndrome and other disorders of mental retardation. Consistent with these findings, miR132 transgenic mice displayed significant deficits in novel object recognition. Together, these data support a role for miR132 as a regulator of neuronal structure and function, and raise the possibility that dysregulation of miR132 could contribute to an array of cognitive disorders.

  18. Prenatal Ethanol Exposure Persistently Alters Endocannabinoid Signaling and Endocannabinoid-Mediated Excitatory Synaptic Plasticity in Ventral Tegmental Area Dopamine Neurons.

    Science.gov (United States)

    Hausknecht, Kathryn; Shen, Ying-Ling; Wang, Rui-Xiang; Haj-Dahmane, Samir; Shen, Roh-Yu

    2017-06-14

    Prenatal ethanol exposure (PE) leads to increased addiction risk which could be mediated by enhanced excitatory synaptic strength in ventral tegmental area (VTA) dopamine (DA) neurons. Previous studies have shown that PE enhances excitatory synaptic strength by facilitating an anti-Hebbian form of long-term potentiation (LTP). In this study, we investigated the effect of PE on endocannabinoid-mediated long-term depression (eCB-LTD) in VTA DA neurons. Rats were exposed to moderate (3 g/kg/d) or high (6 g/kg/d) levels of ethanol during gestation. Whole-cell recordings were conducted in male offspring between 4 and 10 weeks old.We found that PE led to increased amphetamine self-administration. Both moderate and high levels of PE persistently reduced low-frequency stimulation-induced eCB-LTD. Furthermore, action potential-independent glutamate release was regulated by tonic eCB signaling in PE animals. Mechanistic studies for impaired eCB-LTD revealed that PE downregulated CB1 receptor function. Interestingly, eCB-LTD in PE animals was rescued by metabotropic glutamate receptor I activation, suggesting that PE did not impair the synthesis/release of eCBs. In contrast, eCB-LTD in PE animals was not rescued by increasing presynaptic activity, which actually led to LTP in PE animals, whereas LTD was still observed in controls. This result shows that the regulation of excitatory synaptic plasticity is fundamentally altered in PE animals. Together, PE leads to impaired eCB-LTD at the excitatory synapses of VTA DA neurons primarily due to CB1 receptor downregulation. This effect could contribute to enhanced LTP and the maintenance of augmented excitatory synaptic strength in VTA DA neurons and increased addiction risk after PE. SIGNIFICANCE STATEMENT Prenatal ethanol exposure (PE) is among many adverse developmental factors known to increase drug addiction risk. Increased excitatory synaptic strength in VTA DA neurons is a critical cellular mechanism for addiction risk. Our

  19. Activity-Dependent Arc Expression and Homeostatic Synaptic Plasticity Are Altered in Neurons from a Mouse Model of Angelman Syndrome

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    Elissa D. Pastuzyn

    2017-07-01

    Full Text Available Angelman syndrome (AS is a neurodevelopmental disorder that results from deletions or mutations in chromosome 15, which usually includes the UBE3A gene. Ube3A protein is an E3 ubiquitin ligase that ubiquitinates proteins and targets them for degradation. The immediate-early gene Arc, a master regulator of synaptic plasticity, was identified as a putative substrate of Ube3A, but there have been conflicting reports on whether Arc is a bona fide E3 ligase substrate. Using multiple approaches, we found no evidence for a physical interaction between Arc and Ube3A in vivo. Nonetheless, activity-induced subcellular distribution of Arc is altered in brains from Ube3am−/p+ mice, with abnormal concentration of Arc at synapses. Furthermore, although activation of Arc transcription is normal, the stability of Arc protein is enhanced in dendrites of hippocampal neurons cultured from Ube3am−/p+ mice. Finally, homeostatic synaptic scaling of surface AMPA receptors does not occur in Ube3am−/p+ hippocampal neurons, reminiscent of neurons that lack Arc protein. Although Ube3A does not seem to bind Arc in a canonical E3 ligase-substrate interaction, Arc-dependent synaptic plasticity is still altered in Ube3am−/p+ mice, which may underlie the cognitive deficits observed in AS.

  20. Activity-Dependent Arc Expression and Homeostatic Synaptic Plasticity Are Altered in Neurons from a Mouse Model of Angelman Syndrome

    Science.gov (United States)

    Pastuzyn, Elissa D.; Shepherd, Jason D.

    2017-01-01

    Angelman syndrome (AS) is a neurodevelopmental disorder that results from deletions or mutations in chromosome 15, which usually includes the UBE3A gene. Ube3A protein is an E3 ubiquitin ligase that ubiquitinates proteins and targets them for degradation. The immediate-early gene Arc, a master regulator of synaptic plasticity, was identified as a putative substrate of Ube3A, but there have been conflicting reports on whether Arc is a bona fide E3 ligase substrate. Using multiple approaches, we found no evidence for a physical interaction between Arc and Ube3A in vivo. Nonetheless, activity-induced subcellular distribution of Arc is altered in brains from Ube3am−/p+ mice, with abnormal concentration of Arc at synapses. Furthermore, although activation of Arc transcription is normal, the stability of Arc protein is enhanced in dendrites of hippocampal neurons cultured from Ube3am−/p+ mice. Finally, homeostatic synaptic scaling of surface AMPA receptors does not occur in Ube3am−/p+ hippocampal neurons, reminiscent of neurons that lack Arc protein. Although Ube3A does not seem to bind Arc in a canonical E3 ligase-substrate interaction, Arc-dependent synaptic plasticity is still altered in Ube3am−/p+ mice, which may underlie the cognitive deficits observed in AS. PMID:28804447

  1. Altered dendritic complexity affects firing properties of cortical layer 2/3 pyramidal neurons in mice lacking the 5-HT3A receptor.

    Science.gov (United States)

    van der Velden, Luuk; van Hooft, Johannes A; Chameau, Pascal

    2012-09-01

    We have previously shown that the serotonergic input on Cajal-Retzius cells, mediated by 5-HT(3) receptors, plays an important role in the early postnatal maturation of the apical dendritic trees of layer 2/3 pyramidal neurons. We reported that knockout mice lacking the 5-HT(3A) receptor showed exuberant apical dendrites of these cortical pyramidal neurons. Because model studies have shown the role of dendritic morphology on neuronal firing pattern, we used the 5-HT(3A) knockout mouse to explore the impact of dendritic hypercomplexity on the electrophysiological properties of this specific class of neurons. Our experimental results show that hypercomplexity of the apical dendritic tuft of layer 2/3 pyramidal neurons affects neuronal excitability by reducing the amount of spike frequency adaptation. This difference in firing pattern, related to a higher dendritic complexity, was accompanied by an altered development of the afterhyperpolarization slope with successive action potentials. Our abstract and realistic neuronal models, which allowed manipulation of the dendritic complexity, showed similar effects on neuronal excitability and confirmed the impact of apical dendritic complexity. Alterations of dendritic complexity, as observed in several pathological conditions such as neurodegenerative diseases or neurodevelopmental disorders, may thus not only affect the input to layer 2/3 pyramidal neurons but also shape their firing pattern and consequently alter the information processing in the cortex.

  2. Trinitrobenzenesulphonic acid colitis alters Na 1.8 channel expression in mouse dorsal root ganglia neurons.

    Science.gov (United States)

    King, D E; Macleod, R J; Vanner, S J

    2009-08-01

    Visceral inflammation evokes hyperexcitability in nociceptive dorsal root ganglia (DRG) neurons and these changes are associated with increased voltage-gated sodium channel (Na(v)) 1.8 current density, but the molecular determinants of these changes are unclear. This study used Western blotting to measure changes in Na(v) 1.7, 1.8 and 1.9 protein expression during trinitrobenzenesulphonic acid (TNBS) colitis and quantitative polymerase chain reaction (PCR) to examine corresponding changes in mRNA. Colonic neurons were labelled with the retrograde tracer Fast Blue injected into the wall of the distal colon and quantitative PCR performed on laser-captured labelled colonic neurons from ganglia at T9-13 or unlabelled DRG neurons from the upper spinal cord. Immunohistochemistry and western blots were performed on whole DRG from the same sites. Fast Blue-labelled neurons demonstrated Na(v) 1.7, 1.8 and 1.9 immunoreactivity. On day 7 of colitis, which correlated with electrophysiological studies, there was a threefold increase in Na(v) 1.8 protein in ganglia from T9 to 13, but Na(v) 1.7 and 1.9 levels were unchanged. There was no corresponding change in the Na(v) 1.8 alpha-subunit mRNA levels. However, on days 2 and 4, Na(v) 1.8 mRNA was decreased 10-fold. Na(v) 1.8 protein and mRNA levels were unchanged in neurons isolated from ganglia in the upper spinal cord, where colonic neurons are not found. These findings suggest that the TNBS evoked increase in Na(v) 1.8 currents is associated with increased numbers of channels. The absence of corresponding changes in transcript suggests a translational or post-translational mechanism, but the 10-fold recovery of transcript preceding this time point also demonstrates a complex transcriptional regulation.

  3. Alterations in the Interplay between Neurons, Astrocytes and Microglia in the Rat Dentate Gyrus in Experimental Models of Neurodegeneration

    Science.gov (United States)

    Lana, Daniele; Ugolini, Filippo; Nosi, Daniele; Wenk, Gary L.; Giovannini, Maria G.

    2017-01-01

    The hippocampus is negatively affected by aging and neurodegenerative diseases leading to impaired learning and memory abilities. A diverse series of progressive modifications in the intercellular communication among neurons, astrocytes and microglia occur in the hippocampus during aging or inflammation. A detailed understanding of the neurobiological modifications that contribute to hippocampal dysfunction may reveal new targets for therapeutic intervention. The current study focussed on the interplay between neurons and astroglia in the Granule Layer (GL) and the Polymorphic Layer (PL) of the Dentate Gyrus (DG) of adult, aged and LPS-treated rats. In GL and PL of aged and LPS-treated rats, astrocytes were less numerous than in adult rats. In GL of LPS-treated rats, astrocytes acquired morphological features of reactive astrocytes, such as longer branches than was observed in adult rats. Total and activated microglia increased in the aged and LPS-treated rats, as compared to adult rats. In the GL of aged and LPS-treated rats many neurons were apoptotic. Neurons decreased significantly in GL and PL of aged but not in rats treated with LPS. In PL of aged and LPS-treated rats many damaged neurons were embraced by microglia cells and were infiltrated by branches of astrocyte, which appeared to be bisecting the cell body, forming triads. Reactive microglia had a scavenging activity of dying neurons, as shown by the presence of neuronal debris within their cytoplasm. The levels of the chemokine fractalkine (CX3CL1) increased in hippocampal homogenates of aged rats and rats treated with LPS, and CX3CL1 immunoreactivity colocalized with activated microglia cells. Here we demonstrated that in the DG of aged and LPS-treated rats, astrocytes and microglia cooperate and participate in phagocytosis/phagoptosis of apoptotic granular neurons. The differential expression/activation of astroglia and the alteration of their intercommunication may be responsible for the different

  4. Alterations in the Interplay between Neurons, Astrocytes and Microglia in the Rat Dentate Gyrus in Experimental Models of Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Daniele Lana

    2017-09-01

    Full Text Available The hippocampus is negatively affected by aging and neurodegenerative diseases leading to impaired learning and memory abilities. A diverse series of progressive modifications in the intercellular communication among neurons, astrocytes and microglia occur in the hippocampus during aging or inflammation. A detailed understanding of the neurobiological modifications that contribute to hippocampal dysfunction may reveal new targets for therapeutic intervention. The current study focussed on the interplay between neurons and astroglia in the Granule Layer (GL and the Polymorphic Layer (PL of the Dentate Gyrus (DG of adult, aged and LPS-treated rats. In GL and PL of aged and LPS-treated rats, astrocytes were less numerous than in adult rats. In GL of LPS-treated rats, astrocytes acquired morphological features of reactive astrocytes, such as longer branches than was observed in adult rats. Total and activated microglia increased in the aged and LPS-treated rats, as compared to adult rats. In the GL of aged and LPS-treated rats many neurons were apoptotic. Neurons decreased significantly in GL and PL of aged but not in rats treated with LPS. In PL of aged and LPS-treated rats many damaged neurons were embraced by microglia cells and were infiltrated by branches of astrocyte, which appeared to be bisecting the cell body, forming triads. Reactive microglia had a scavenging activity of dying neurons, as shown by the presence of neuronal debris within their cytoplasm. The levels of the chemokine fractalkine (CX3CL1 increased in hippocampal homogenates of aged rats and rats treated with LPS, and CX3CL1 immunoreactivity colocalized with activated microglia cells. Here we demonstrated that in the DG of aged and LPS-treated rats, astrocytes and microglia cooperate and participate in phagocytosis/phagoptosis of apoptotic granular neurons. The differential expression/activation of astroglia and the alteration of their intercommunication may be responsible for

  5. ALTERED HIPPOCAMPAL NEUROGENESIS AND AMYGDALAR NEURONAL ACTIVITY IN ADULT MICE WITH REPEATED EXPERIENCE OF AGGRESSION

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    Dmitriy eSmagin

    2015-12-01

    Full Text Available The repeated experience of winning in a social conflict setting elevates levels of aggression and may lead to violent behavioral patterns. Here we use a paradigm of repeated aggression and fighting deprivation to examine changes in behavior, neurogenesis, and neuronal activity in mice with positive fighting experience. We show that for males, repeated positive fighting experience induces persistent demonstration of aggression and stereotypic behaviors in daily agonistic interactions, enhances aggressive motivation, and elevates levels of anxiety. When winning males are deprived of opportunities to engage in further fights, they demonstrate increased levels of aggressiveness. Positive fighting experience results in increased levels of progenitor cell proliferation and production of young neurons in the hippocampus. This increase is not diminished after a fighting deprivation period. Furthermore, repeated winning experience decreases the number of activated (c-fos positive cells in the basolateral amygdala and increases the number of activated cells in the hippocampus; a subsequent no-fight period restores the number of c-fos-positive cells. Our results indicate that extended positive fighting experience in a social conflict heightens aggression, increases proliferation of neuronal progenitors and production of young neurons in the hippocampus, and decreases neuronal activity in the amygdala; these changes can be modified by depriving the winners of the opportunity for further fights.

  6. Rapid reconstruction of 3D neuronal morphology from light microscopy images with augmented rayburst sampling.

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    Xing Ming

    Full Text Available Digital reconstruction of three-dimensional (3D neuronal morphology from light microscopy images provides a powerful technique for analysis of neural circuits. It is time-consuming to manually perform this process. Thus, efficient computer-assisted approaches are preferable. In this paper, we present an innovative method for the tracing and reconstruction of 3D neuronal morphology from light microscopy images. The method uses a prediction and refinement strategy that is based on exploration of local neuron structural features. We extended the rayburst sampling algorithm to a marching fashion, which starts from a single or a few seed points and marches recursively forward along neurite branches to trace and reconstruct the whole tree-like structure. A local radius-related but size-independent hemispherical sampling was used to predict the neurite centerline and detect branches. Iterative rayburst sampling was performed in the orthogonal plane, to refine the centerline location and to estimate the local radius. We implemented the method in a cooperative 3D interactive visualization-assisted system named flNeuronTool. The source code in C++ and the binaries are freely available at http://sourceforge.net/projects/flneurontool/. We validated and evaluated the proposed method using synthetic data and real datasets from the Digital Reconstruction of Axonal and Dendritic Morphology (DIADEM challenge. Then, flNeuronTool was applied to mouse brain images acquired with the Micro-Optical Sectioning Tomography (MOST system, to reconstruct single neurons and local neural circuits. The results showed that the system achieves a reasonable balance between fast speed and acceptable accuracy, which is promising for interactive applications in neuronal image analysis.

  7. Functional alterations of the ubiquitin-proteasome system in motor neurons of a mouse model of familial amyotrophic lateral sclerosis.

    Science.gov (United States)

    Cheroni, Cristina; Marino, Marianna; Tortarolo, Massimo; Veglianese, Pietro; De Biasi, Silvia; Fontana, Elena; Zuccarello, Laura Vitellaro; Maynard, Christa J; Dantuma, Nico P; Bendotti, Caterina

    2009-01-01

    In familial and sporadic amyotrophic lateral sclerosis (ALS) and in rodent models of the disease, alterations in the ubiquitin-proteasome system (UPS) may be responsible for the accumulation of potentially harmful ubiquitinated proteins, leading to motor neuron death. In the spinal cord of transgenic mice expressing the familial ALS superoxide dismutase 1 (SOD1) gene mutation G93A (SOD1G93A), we found a decrease in constitutive proteasome subunits during disease progression, as assessed by real-time PCR and immunohistochemistry. In parallel, an increased immunoproteasome expression was observed, which correlated with a local inflammatory response due to glial activation. These findings support the existence of proteasome modifications in ALS vulnerable tissues. To functionally investigate the UPS in ALS motor neurons in vivo, we crossed SOD1G93A mice with transgenic mice that express a fluorescently tagged reporter substrate of the UPS. In double-transgenic Ub(G76V)-GFP /SOD1G93A mice an increase in Ub(G76V)-GFP reporter, indicative of UPS impairment, was detectable in a few spinal motor neurons and not in reactive astrocytes or microglia, at symptomatic stage but not before symptoms onset. The levels of reporter transcript were unaltered, suggesting that the accumulation of Ub(G76V)-GFP was due to deficient reporter degradation. In some motor neurons the increase of Ub(G76V)-GFP was accompanied by the accumulation of ubiquitin and phosphorylated neurofilaments, both markers of ALS pathology. These data suggest that UPS impairment occurs in motor neurons of mutant SOD1-linked ALS mice and may play a role in the disease progression.

  8. Rapid and extensive alteration of phosphorus speciation during oxic storage of wet sediment samples.

    Directory of Open Access Journals (Sweden)

    Peter Kraal

    Full Text Available The chemical forms of phosphorus (P in sediments are routinely measured in studies of P in modern and ancient marine environments. However, samples for such analyses are often exposed to atmospheric oxygen during storage and handling. Recent work suggests that long-term exposure of pyrite-bearing sediments can lead to a decline in apatite P and an increase in ferric Fe-bound P. Here, we report on alterations in P speciation in reducing modern Baltic Sea sediments that we deliberately exposed to atmospheric oxygen for a period of either one week or one year. During oxidation of the sediment, extensive changes occurred in all measured P reservoirs. Exchangeable P all but disappeared during the first week of exposure, likely reflecting adsorption of porewater PO4 by Fe(III (oxyhydroxides (i.e. ferric Fe-bound P formation. Detrital and organic P were also rapidly affected: decreases in both reservoirs were already observed after the first week of exposure to atmospheric oxygen. This was likely because of acidic dissolution of detrital apatite and oxidation of organic matter, respectively. These processes produced dissolved PO4 that was then scavenged by Fe(III (oxyhydroxides. Interestingly, P in authigenic calcium phosphates (i.e. apatite: authigenic Ca-P remained unaffected after the first week of exposure, which we attributed to the shielding effect of microfossils in which authigenic Ca-P occurs in Baltic Sea sediments. This effect was transient; a marked decrease in the authigenic Ca-P pool was observed in the sediments after one year of exposure to oxygen. In summary, we show that handling and storage of wet sediments under oxic conditions can lead to rapid and extensive alteration of the original sediment P speciation.

  9. HIV-1 Tat activates neuronal ryanodine receptors with rapid induction of the unfolded protein response and mitochondrial hyperpolarization.

    Directory of Open Access Journals (Sweden)

    John P Norman

    Full Text Available Neurologic disease caused by human immunodeficiency virus type 1 (HIV-1 is ultimately refractory to highly active antiretroviral therapy (HAART because of failure of complete virus eradication in the central nervous system (CNS, and disruption of normal neural signaling events by virally induced chronic neuroinflammation. We have previously reported that HIV-1 Tat can induce mitochondrial hyperpolarization in cortical neurons, thus compromising the ability of the neuron to buffer calcium and sustain energy production for normal synaptic communication. In this report, we demonstrate that Tat induces rapid loss of ER calcium mediated by the ryanodine receptor (RyR, followed by the unfolded protein response (UPR and pathologic dilatation of the ER in cortical neurons in vitro. RyR antagonism attenuated both Tat-mediated mitochondrial hyperpolarization and UPR induction. Delivery of Tat to murine CNS in vivo also leads to long-lasting pathologic ER dilatation and mitochondrial morphologic abnormalities. Finally, we performed ultrastructural studies that demonstrated mitochondria with abnormal morphology and dilated endoplasmic reticulum (ER in brain tissue of patients with HIV-1 inflammation and neurodegeneration. Collectively, these data suggest that abnormal RyR signaling mediates the neuronal UPR with failure of mitochondrial energy metabolism, and is a critical locus for the neuropathogenesis of HIV-1 in the CNS.

  10. Skeletal alterations associated with the use of bonded rapid maxillary expansion appliance.

    Science.gov (United States)

    Rossi, Moara de; Rossi, Andiara de; Abrão, Jorge

    2011-01-01

    Bonded maxillary expansion appliances have been suggested to control increases in the vertical dimension of the face after rapid maxillary expansion (RME). However, there is still no consensus in the literature about its real skeletal effects. The purpose of this prospective study was to evaluate, longitudinally, the vertical and sagittal cephalometric alterations after RME performed with bonded maxillary expansion appliance. The sample consisted of 26 children, with a mean age of 8.7 years (range: 6.9-10.9 years), with posterior skeletal crossbite and indication for RME. After maxillary expansion, the bonded appliance was used as a fixed retention for 3.4 months, being replaced by a removable retention subsequently. The cephalometric study was performed onto lateral radiographs, taken before treatment was started, and again 6.3 months after removing the bonded appliance. Intra-group comparison was made using paired t test. The results showed that there were no significant sagittal skeletal changes at the end of treatment. There was a small vertical skeletal increase in five of the eleven evaluated cephalometric measures. The maxilla displaced downward, but it did not modify the facial growth patterns or the direction of the mandible growth. Under the specific conditions of this research, it may be concluded that RME with acrylic bonded maxillary expansion appliance did promote signifciant vertical or sagittal cephalometric alterations. The vertical changes found with the use of the bonded appliance were small and probably transitory, similar to those occurred with the use of banded expansion appliances.

  11. Hedonic reactivity to visual and olfactory cues: rapid facial electromyographic reactions are altered in anorexia nervosa.

    Science.gov (United States)

    Soussignan, Robert; Schaal, Benoist; Rigaud, Daniel; Royet, Jean-Pierre; Jiang, Tao

    2011-03-01

    Though it has been suggested that hedonic processing is altered in anorexia nervosa (AN), few studies have used objective measures to assess affective processes in this eating disorder. Accordingly, we investigated facial electromyographic, autonomic and subjective reactivity to the smell and sight of food and non-food stimuli, and assessed more particularly rapid facial reactions reflecting automatic processing of pleasantness. AN and healthy control (HC) women were exposed, before and after a standardized lunch, to pictures and odorants of foods differing in energy density, as well as to non-food sensory cues. Whereas the temporal profile of zygomatic activity in AN patients was typified by a fast drop to sensory cues within the 1000 ms following stimulus onset, HC showed a larger EMG reactivity to pictures in a 800-1000 ms time window. In contrast, pleasantness ratings discriminated the two groups only for high energy density food cues suggesting a partial dissociation between objective and subjective measures of hedonic processes in AN patients. The findings suggest that the automatic processing of pleasantness might be altered in AN, with the sensitivity to reward being modulated by controlled processes. Copyright © 2010 Elsevier B.V. All rights reserved.

  12. NGF-dependent axon growth and regeneration are altered in sympathetic neurons of dystrophic mdx mice

    NARCIS (Netherlands)

    Lombardi, Loredana; Persiconi, Irene; Gallo, Alessandra; Hoogenraad, Casper C|info:eu-repo/dai/nl/227263502; De Stefano, Maria Egle

    Duchenne muscular dystrophy (DMD) is a lethal disease, determined by lack of dystrophin (Dp427), a muscular cytoskeletal protein also expressed by selected neuronal populations. Consequently, besides muscular wasting, both human patients and DMD animal models suffer several neural disorders. In

  13. Amorphous material from the rapid evaporation of basalt weathering solutions: Implications for Amazonian alteration

    Science.gov (United States)

    Smith, R.; Horgan, B. H. N.; Christensen, P. R.

    2016-12-01

    Amorphous silicates of ambiguous origin are detected on the Martian surface through orbiter and rover measurements. Secondary amorphous silicates might precipitate from rapidly evaporating weathering solutions under Amazonian ( 3 BYA - present) surface conditions. Yet, such phases are poorly understood and are underrepresented in infrared spectral libraries. Amazonian weathering was simulated by dissolving two basaltic tephra compositions in DI water under two different atmospheres (1: oxidizing and 2: simulated Martian). The resulting weathering solutions were rapidly evaporated into sample cups. Precipitate mineralogy was studied using visible and near-infrared (VNIR) and thermal-infrared (TIR) spectroscopy and x-ray diffraction (XRD). Solution compositions were analyzed using Ion Chromatography (IC) and Inductively Coupled Plasma Mass-Spectroscopy (ICP-MS). All experiments formed hydrated amorphous silicates and nanophase iron-oxides, but precipitates from solutions formed under a simulated Martian atmosphere also contain crystalline carbonate and sulfate minerals. The oxidizing atmosphere precipitates are also S-bearing, based on solution chemistry, but no crystalline sulfates were unambiguously detected. The TIR spectra of all samples exhibit a spectral feature at 460 cm-1 that was previously only known to be present in the spectra of basaltic glass and some terrestrial palagonitized basalt samples, indicating that the precipitates are new to spectral libraries. Ongoing characterization will help determine the composition and structure of the amorphous phases. TIR spectral and XRD instruments on the Spirit and Mars Science Laboratory (MSL) rovers both indicate high abundances of basaltic glass in rock and soil samples, despite chemical evidence for aqueous alteration. Our results suggest that these measurements are consistent with secondary amorphous silicates formed through the rapid evaporation of basalt weathering solutions. Thus, transient water

  14. Rapid single-step induction of functional neurons from human pluripotent stem cells.

    Science.gov (United States)

    Zhang, Yingsha; Pak, Changhui; Han, Yan; Ahlenius, Henrik; Zhang, Zhenjie; Chanda, Soham; Marro, Samuele; Patzke, Christopher; Acuna, Claudio; Covy, Jason; Xu, Wei; Yang, Nan; Danko, Tamas; Chen, Lu; Wernig, Marius; Südhof, Thomas C

    2013-06-05

    Available methods for differentiating human embryonic stem cells (ESCs) and induced pluripotent cells (iPSCs) into neurons are often cumbersome, slow, and variable. Alternatively, human fibroblasts can be directly converted into induced neuronal (iN) cells. However, with present techniques conversion is inefficient, synapse formation is limited, and only small amounts of neurons can be generated. Here, we show that human ESCs and iPSCs can be converted into functional iN cells with nearly 100% yield and purity in less than 2 weeks by forced expression of a single transcription factor. The resulting ES-iN or iPS-iN cells exhibit quantitatively reproducible properties independent of the cell line of origin, form mature pre- and postsynaptic specializations, and integrate into existing synaptic networks when transplanted into mouse brain. As illustrated by selected examples, our approach enables large-scale studies of human neurons for questions such as analyses of human diseases, examination of human-specific genes, and drug screening. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Misfolded SOD1 associated with motor neuron mitochondria alters mitochondrial shape and distribution prior to clinical onset.

    Directory of Open Access Journals (Sweden)

    Christine Vande Velde

    Full Text Available Mutations in superoxide dismutase (SOD1 are causative for inherited amyotrophic lateral sclerosis. A proportion of SOD1 mutant protein is misfolded onto the cytoplasmic face of mitochondria in one or more spinal cord cell types. By construction of mice in which mitochondrially targeted enhanced green fluorescent protein is selectively expressed in motor neurons, we demonstrate that axonal mitochondria of motor neurons are primary in vivo targets for misfolded SOD1. Mutant SOD1 alters axonal mitochondrial morphology and distribution, with dismutase active SOD1 causing mitochondrial clustering at the proximal side of Schmidt-Lanterman incisures within motor axons and dismutase inactive SOD1 producing aberrantly elongated axonal mitochondria beginning pre-symptomatically and increasing in severity as disease progresses. Somal mitochondria are altered by mutant SOD1, with loss of the characteristic cylindrical, networked morphology and its replacement by a less elongated, more spherical shape. These data indicate that mutant SOD1 binding to mitochondria disrupts normal mitochondrial distribution and size homeostasis as early pathogenic features of SOD1 mutant-mediated ALS.

  16. NOTCH SIGNALING ALTERS SENSORY OR NEURONAL CELL FATE SPECIFICATION OF INNER EAR STEM CELLS

    Science.gov (United States)

    Jeon, Sang-Jun; Fujioka, Masato; Kim, Shi-Chan; Edge, Albert S.B.

    2011-01-01

    Multipotent progenitor cells in the otic placode give rise to the specialized cell types of the inner ear, including neurons, supporting cells and hair cells. The mechanisms governing acquisition of specific fates by the cells that form the cochleovestibular organs remain poorly characterized. Here we show that whereas blocking Notch signaling with a γ-secretase inhibitor increased the conversion of inner ear stem cells to hair cells by a mechanism that involved the upregulation of bHLH transcription factor, Math1 (mouse Atoh1), differentiation to a neuronal lineage was increased by expression of the Notch intracellular domain. The shift to a neuronal lineage could be attributed in part to the continued cell proliferation in cells that did not undergo sensory cell differentiation due to the high Notch signaling, but also involved upregulation of Ngn1. The Notch intracellular domain influenced Ngn1 indirectly by upregulation of Sox2, a transcription factor expressed in many neural progenitor cells, and directly by an interaction with an RBP-J binding site in the Ngn1 promoter/enhancer. The induction of Ngn1 was blocked partially by mutation of the RBP-J site and nearly completely when the mutation was combined with inhibition of Sox2 expression. Thus Notch signaling had a significant role in the fate specification of neurons and hair cells from inner ear stem cells, and decisions about cell fate were mediated in part by a differential effect of combinatorial signaling by Notch and Sox2 on the expression of bHLH transcription factors. PMID:21653840

  17. Acute pressure on the sciatic nerve results in rapid inhibition of the wide dynamic range neuronal response.

    Science.gov (United States)

    Wang, Wenxue; Tan, Wei; Luo, Danping; Lin, Jianhua; Yu, Yaoqing; Wang, Qun; Zhao, Wangyeng; Wu, Buling; Chen, Jun; He, Jiman

    2012-12-04

    Acute pressure on the sciatic nerve has recently been reported to provide rapid short-term relief of pain in patients with various pathologies. Wide dynamic range (WDR) neurons transmit nociceptive information from the dorsal horn to higher brain centers. In the present study, we examined the effect of a 2-min application of sciatic nerve pressure on WDR neuronal activity in anesthetized male Sprague-Dawley rats. Experiments were carried out on 41 male Sprague-Dawley albino rats weighing 160-280 grams. Dorsal horn WDR neurons were identified on the basis of characteristic responses to mechanical stimuli applied to the cutaneous receptive field. Acute pressure was applied for 2 min to the sciatic nerve using a small vascular clip. The responses of WDR neurons to three mechanical stimuli applied to the cutaneous receptive field were recorded before, and 2, 5 and 20 min after cessation of the 2-min pressure application on the sciatic nerve. Two-min pressure applied to the sciatic nerve caused rapid attenuation of the WDR response to pinching, pressure and brushing stimuli applied to the cutaneous receptive field. Maximal attenuation of the WDR response to pinching and pressure was noted 5 min after release of the 2-min pressure on the sciatic nerve. The mean firing rate decreased from 31.7±1.7 Hz to 13±1.4 Hz upon pinching (p < 0.001), from 31.2±2.3 Hz to 10.9±1.4 Hz (p < 0.001) when pressure was applied, and from 18.9±1.2 Hz to 7.6±1.1 Hz (p < 0.001) upon brushing. Thereafter, the mean firing rates gradually recovered. Our results indicate that acute pressure applied to the sciatic nerve exerts a rapid inhibitory effect on the WDR response to both noxious and innocuous stimuli. Our results may partially explain the rapid analgesic effect of acute sciatic nerve pressure noted in clinical studies, and also suggest a new model for the study of pain.

  18. The neurosteroid dehydroepiandrosterone (DHEA) and its metabolites alter 5-HT neuronal activity via modulation of GABAA receptors.

    Science.gov (United States)

    Gartside, S E; Griffith, N C; Kaura, V; Ingram, C D

    2010-11-01

    Dehydroepiandrosterone (DHEA) and its metabolites, DHEA-sulphate (DHEA-S) and androsterone, have neurosteroid activity. In this study, we examined whether DHEA, DHEA-S and androsterone, can influence serotonin (5-HT) neuronal firing activity via modulation of γ-aminobutryic acid (GABA(A)) receptors. The firing of presumed 5-HT neurones in a slice preparation containing rat dorsal raphe nucleus was inhibited by the GABA(A) receptor agonists 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridinyl-3-ol (THIP) (25 μM) and GABA (100 μM). DHEA (100 and 300 μM) and DHEA-S (1, 10 and 100 μM) caused a rapid and reversible attenuation of the response to THIP. DHEA (100 μM) and DHEA-S (100 μM) also attenuated the effect of GABA. Androsterone (10 and 30 μM) markedly enhanced the inhibitory response to THIP (25 μM). The effect was apparent during androsterone administration but persisted and even increased in magnitude after drug wash-out. The data indicate that GABA(A) receptor-mediated regulation of 5-HT neuronal firing is sensitive to negative modulation by DHEA and its metabolite DHEA-S is sensitive to positive modulation by the metabolite androsterone. The effects of these neurosteroids on GABA(A) receptor-mediated regulation of 5-HT firing may underlie some of the reported behavioural and psychological effects of endogenous and exogenous DHEA.

  19. 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.

  20. Neurodegeneration in Autoimmune Optic Neuritis Is Associated with Altered APP Cleavage in Neurons and Up-Regulation of p53.

    Directory of Open Access Journals (Sweden)

    Sabine Herold

    Full Text Available Multiple Sclerosis (MS is a chronic autoimmune inflammatory disease of the central nervous system (CNS. Histopathological and radiological analysis revealed that neurodegeneration occurs early in the disease course. However, the pathological mechanisms involved in neurodegeneration are poorly understood. Myelin oligodendrocyte glycoprotein (MOG-induced experimental autoimmune encephalomyelitis (EAE in Brown Norway rats (BN-rats is a well-established animal model, especially of the neurodegenerative aspects of MS. Previous studies in this animal model indicated that loss of retinal ganglion cells (RGCs, the neurons that form the axons of the optic nerve, occurs in the preclinical phase of the disease and is in part independent of overt histopathological changes of the optic nerve. Therefore, the aim of this study was to identify genes which are involved in neuronal cell loss at different disease stages of EAE. Furthermore, genes that are highly specific for autoimmune-driven neurodegeneration were compared to those regulated in RGCs after optic nerve axotomy at corresponding time points. Using laser capture micro dissection we isolated RNA from unfixed RGCs and performed global transcriptome analysis of retinal neurons. In total, we detected 582 genes sequentially expressed in the preclinical phase and 1150 genes in the clinical manifest EAE (P 1.5. Furthermore, using ingenuity pathway analysis (IPA, we identified amyloid precursor protein (APP as a potential upstream regulator of changes in gene expression in the preclinical EAE but neither in clinical EAE, nor at any time point after optic nerve transection. Therefore, the gene pathway analysis lead to the hypothesis that altered cleavage of APP in neurons in the preclinical phase of EAE leads to the enhanced production of APP intracellular domain (AICD, which in turn acts as a transcriptional regulator and thereby initiates an apoptotic signaling cascade via up-regulation of the target gene p

  1. Rapid Alterations in Perirenal Adipose Tissue Transcriptomic Networks with Cessation of Voluntary Running.

    Directory of Open Access Journals (Sweden)

    Gregory N Ruegsegger

    Full Text Available In maturing rats, the growth of abdominal fat is attenuated by voluntary wheel running. After the cessation of running by wheel locking, a rapid increase in adipose tissue growth to a size that is similar to rats that have never run (i.e. catch-up growth has been previously reported by our lab. In contrast, diet-induced increases in adiposity have a slower onset with relatively delayed transcriptomic responses. The purpose of the present study was to identify molecular pathways associated with the rapid increase in adipose tissue after ending 6 wks of voluntary running at the time of puberty. Age-matched, male Wistar rats were given access to running wheels from 4 to 10 weeks of age. From the 10th to 11th week of age, one group of rats had continued wheel access, while the other group had one week of wheel locking. Perirenal adipose tissue was extracted, RNA sequencing was performed, and bioinformatics analyses were executed using Ingenuity Pathway Analysis (IPA. IPA was chosen to assist in the understanding of complex 'omics data by integrating data into networks and pathways. Wheel locked rats gained significantly more fat mass and significantly increased body fat percentage between weeks 10-11 despite having decreased food intake, as compared to rats with continued wheel access. IPA identified 646 known transcripts differentially expressed (p < 0.05 between continued wheel access and wheel locking. In wheel locked rats, IPA revealed enrichment of transcripts for the following functions: extracellular matrix, macrophage infiltration, immunity, and pro-inflammatory. These findings suggest that increases in visceral adipose tissue that accompanies the cessation of pubertal physical activity are associated with the alteration of multiple pathways, some of which may potentiate the development of pubertal obesity and obesity-associated systemic low-grade inflammation that occurs later in life.

  2. Rapid Alterations in Perirenal Adipose Tissue Transcriptomic Networks with Cessation of Voluntary Running.

    Science.gov (United States)

    Ruegsegger, Gregory N; Company, Joseph M; Toedebusch, Ryan G; Roberts, Christian K; Roberts, Michael D; Booth, Frank W

    2015-01-01

    In maturing rats, the growth of abdominal fat is attenuated by voluntary wheel running. After the cessation of running by wheel locking, a rapid increase in adipose tissue growth to a size that is similar to rats that have never run (i.e. catch-up growth) has been previously reported by our lab. In contrast, diet-induced increases in adiposity have a slower onset with relatively delayed transcriptomic responses. The purpose of the present study was to identify molecular pathways associated with the rapid increase in adipose tissue after ending 6 wks of voluntary running at the time of puberty. Age-matched, male Wistar rats were given access to running wheels from 4 to 10 weeks of age. From the 10th to 11th week of age, one group of rats had continued wheel access, while the other group had one week of wheel locking. Perirenal adipose tissue was extracted, RNA sequencing was performed, and bioinformatics analyses were executed using Ingenuity Pathway Analysis (IPA). IPA was chosen to assist in the understanding of complex 'omics data by integrating data into networks and pathways. Wheel locked rats gained significantly more fat mass and significantly increased body fat percentage between weeks 10-11 despite having decreased food intake, as compared to rats with continued wheel access. IPA identified 646 known transcripts differentially expressed (p rats, IPA revealed enrichment of transcripts for the following functions: extracellular matrix, macrophage infiltration, immunity, and pro-inflammatory. These findings suggest that increases in visceral adipose tissue that accompanies the cessation of pubertal physical activity are associated with the alteration of multiple pathways, some of which may potentiate the development of pubertal obesity and obesity-associated systemic low-grade inflammation that occurs later in life.

  3. A rapid method for combined laser scanning confocal microscopic and electron microscopic visualization of biocytin or neurobiotin-labeled neurons.

    Science.gov (United States)

    Sun, X J; Tolbert, L P; Hildebrand, J G; Meinertzhagen, I A

    1998-02-01

    Intracellular recording and dye filling are widely used to correlate the morphology of a neuron with its physiology. With laser scanning confocal microscopy, the complex shapes of labeled neurons in three dimensions can be reconstructed rapidly, but this requires fluorescent dyes. These dyes are neither permanent nor electron dense and therefore do not allow investigation by electron microscopy. Here we report a technique that quickly and easily converts a fluorescent label into a more stable and electron-dense stain. With this technique, a neuron is filled with Neurobiotin or biocytin, reacted with fluorophore-conjugated avidin, and imaged by confocal microscopy. To permit long-term storage or EM study, the fluorescent label is then converted to a stable electron-dense material by a single-step conversion using a commercially available ABC kit. We find that the method, which apparently relies on recognition of avidin's excess biotin binding sites by the biotin-peroxidase conjugate, is both faster and less labor intensive than photo-oxidation procedures in common use. The technique is readily adaptable to immunocytochemistry with biotinylated probes, as we demonstrate using anti-serotonin as an example.

  4. Fermentable carbohydrate alters hypothalamic neuronal activity and protects against the obesogenic environment.

    Science.gov (United States)

    Anastasovska, Jelena; Arora, Tulika; Sanchez Canon, Gina J; Parkinson, James R C; Touhy, Kieran; Gibson, Glen R; Nadkarni, Nachiket A; So, Po-Wah; Goldstone, Anthony P; Thomas, E Louise; Hankir, Mohammed K; Van Loo, Jan; Modi, Neena; Bell, Jimmy D; Frost, Gary

    2012-05-01

    Obesity has become a major global health problem. Recently, attention has focused on the benefits of fermentable carbohydrates on modulating metabolism. Here, we take a system approach to investigate the physiological effects of supplementation with oligofructose-enriched inulin (In). We hypothesize that supplementation with this fermentable carbohydrate will not only lead to changes in body weight and composition, but also to modulation in neuronal activation in the hypothalamus. Male C57BL/6 mice were maintained on a normal chow diet (control) or a high fat (HF) diet supplemented with either oligofructose-enriched In or corn starch (Cs) for 9 weeks. Compared to HF+Cs diet, In supplementation led to significant reduction in average daily weight gain (mean ± s.e.m.: 0.19 ± 0.01 g vs. 0.26 ± 0.02 g, P < 0.01), total body adiposity (24.9 ± 1.2% vs. 30.7 ± 1.4%, P < 0.01), and lowered liver fat content (11.7 ± 1.7% vs. 23.8 ± 3.4%, P < 0.01). Significant changes were also observed in fecal bacterial distribution, with increases in both Bifidobacteria and Lactobacillius and a significant increase in short chain fatty acids (SCFA). Using manganese-enhanced MRI (MEMRI), we observed a significant increase in neuronal activation within the arcuate nucleus (ARC) of animals that received In supplementation compared to those fed HF+Cs diet. In conclusion, we have demonstrated for the first time, in the same animal, a wide range of beneficial metabolic effects following supplementation of a HF diet with oligofructose-enriched In, as well as significant changes in hypothalamic neuronal activity.

  5. Alterations in the structure of neuronal inhibitory networks in psychiatric disorders

    OpenAIRE

    Gilabert Juan, Javier

    2013-01-01

    Introducción El trabajo de investigación de la presente Tesis doctoral realizado por Javier Gilabert Juan, ha estado centrado en el estudio de la plasticidad estructural neuronal de interneuronas en trastornos psiquiátricos, abordado desde diferentes estrategias de estudio: modelos animales, estudios en muestras de cerebro postmortem de pacientes con enfermedades psiquiátricas y estudios de asociación. Durante los últimos años, diversos trabajos han puesto de manifiesto que cierta...

  6. Visual Stimuli Evoked Action Potentials Trigger Rapidly Propagating Dendritic Calcium Transients in the Frog Optic Tectum Layer 6 Neurons.

    Directory of Open Access Journals (Sweden)

    Gytis Svirskis

    Full Text Available The superior colliculus in mammals or the optic tectum in amphibians is a major visual information processing center responsible for generation of orientating responses such as saccades in monkeys or prey catching avoidance behavior in frogs. The conserved structure function of the superior colliculus the optic tectum across distant species such as frogs, birds monkeys permits to draw rather general conclusions after studying a single species. We chose the frog optic tectum because we are able to perform whole-cell voltage-clamp recordings fluorescence imaging of tectal neurons while they respond to a visual stimulus. In the optic tectum of amphibians most visual information is processed by pear-shaped neurons possessing long dendritic branches, which receive the majority of synapses originating from the retinal ganglion cells. Since the first step of the retinal input integration is performed on these dendrites, it is important to know whether this integration is enhanced by active dendritic properties. We demonstrate that rapid calcium transients coinciding with the visual stimulus evoked action potentials in the somatic recordings can be readily detected up to the fine branches of these dendrites. These transients were blocked by calcium channel blockers nifedipine CdCl2 indicating that calcium entered dendrites via voltage-activated L-type calcium channels. The high speed of calcium transient propagation, >300 μm in <10 ms, is consistent with the notion that action potentials, actively propagating along dendrites, open voltage-gated L-type calcium channels causing rapid calcium concentration transients in the dendrites. We conclude that such activation by somatic action potentials of the dendritic voltage gated calcium channels in the close vicinity to the synapses formed by axons of the retinal ganglion cells may facilitate visual information processing in the principal neurons of the frog optic tectum.

  7. Function of Metallothionein-3 in Neuronal Cells: Do Metal Ions Alter Expression Levels of MT3?

    Directory of Open Access Journals (Sweden)

    Jamie Bousleiman

    2017-05-01

    Full Text Available A study of factors proposed to affect metallothionein-3 (MT3 function was carried out to elucidate the opaque role MT3 plays in human metalloneurochemistry. Gene expression of Mt2 and Mt3 was examined in tissues extracted from the dentate gyrus of mouse brains and in human neuronal cell cultures. The whole-genome gene expression analysis identified significant variations in the mRNA levels of genes associated with zinc homeostasis, including Mt2 and Mt3. Mt3 was found to be the most differentially expressed gene in the identified groups, pointing to the existence of a factor, not yet identified, that differentially controls Mt3 expression. To examine the expression of the human metallothioneins in neurons, mRNA levels of MT3 and MT2 were compared in BE(2C and SH-SY5Y cell cultures treated with lead, zinc, cobalt, and lithium. MT2 was highly upregulated by Zn2+ in both cell cultures, while MT3 was not affected, and no other metal had an effect on either MT2 or MT3.

  8. Exposure to ambient ultrafine particulate matter alters the expression of genes in primary human neurons.

    Science.gov (United States)

    Solaimani, Parrisa; Saffari, Arian; Sioutas, Constantinos; Bondy, Stephen C; Campbell, Arezoo

    2017-01-01

    Exposure to ambient particulate matter (PM) has been associated with the onset of neurodevelopmental and neurodegenerative disorders, but the mechanism of toxicity remains unclear. To gain insight into this neurotoxicity, this study sought to examine global gene expression changes caused by exposure to ambient ultrafine PM. Microarray analysis was performed on primary human neurons derived from fetal brain tissue after a 24h exposure to 20μg/mL of ambient ultrafine particles. We found a majority of the changes in noncoding RNAs, which are involved in epigenetic regulation of gene expression, and thereby could impact the expression of several other protein coding gene targets. Although neurons from biologically different lot numbers were used, we found a significant increase in the expression of metallothionein 1A and 1F in all samples after exposure to particulate matter as confirmed by quantitative PCR. These metallothionein 1 proteins are responsible for neuroprotection after exposure to environmental insult but prolonged induction can be toxic. Epidemiological studies have reported that in utero exposure to ultrafine PM not only leads to neurodevelopmental and behavioral abnormalities, but may also predispose the progeny to neurodegenerative disease later in life by genetic imprinting. Our results pinpoint some of the PM-induced genetic changes that may underlie these findings. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Monosodium glutamate alters the response properties of rat trigeminovascular neurons through activation of peripheral NMDA receptors.

    Science.gov (United States)

    O'Brien, Melissa; Cairns, Brian E

    2016-10-15

    Ingestion of monosodium glutamate (MSG) has been shown to cause headaches in healthy individuals and trigger migraine-like headaches in migraine sufferers. We combined immunohistochemistry, in vivo electrophysiology, and laser Doppler recordings of dural vasculature to investigate the effect of systemic administration of MSG on the trigeminovascular pathway. Immunohistochemical analysis confirmed the expression of NMDA receptors on nerve fibers innervating dural blood vessels and excitatory amino acid transporter 2 on dural blood vessels. Systemic administration of MSG (50mg/kg) evoked an increase in ongoing discharge in 5/6 spinal trigeminal subnucleus caudalis (SpVc) neurons with dural input recorded from male and female rats, respectively, as well as lowering their mechanical activation threshold. There were no sex-related differences in these effects of MSG. Neuronal discharge and mechanical sensitization were significantly attenuated by co-injection with the peripherally restricted NMDA receptor antagonist (2R)-amino-5-phosphonovaleric acid (APV) in both sexes. Systemic administration of MSG induced a 24.5% and 20.6% increase in dural flux in male and female rats, respectively. These results suggest that MSG-induced headache is mediated by the activation of peripheral NMDA receptors and subsequent dural vasodilation. Peripheral NMDA receptors are a potential target for the development of new drugs to treat headaches. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  10. Urotensin II modulates rapid eye movement sleep through activation of brainstem cholinergic neurons

    DEFF Research Database (Denmark)

    Huitron-Resendiz, Salvador; Kristensen, Morten Pilgaard; Sánchez-Alavez, Manuel

    2005-01-01

    administration of UII into the PPT nucleus increases REM sleep without inducing changes in the cortical blood flow. Intracerebroventricular injection of UII enhances both REM sleep and wakefulness and reduces slow-wave sleep 2. Intracerebroventricular, but not local, administration of UII increases cortical...... blood flow. Moreover, whole-cell recordings from rat-brain slices show that UII selectively excites cholinergic PPT neurons via an inward current and membrane depolarization that were accompanied by membrane conductance decreases. This effect does not depend on action potential generation or fast...

  11. Pulvinar neurons reveal neurobiological evidence of past selection for rapid detection of snakes.

    Science.gov (United States)

    Van Le, Quan; Isbell, Lynne A; Matsumoto, Jumpei; Nguyen, Minh; Hori, Etsuro; Maior, Rafael S; Tomaz, Carlos; Tran, Anh Hai; Ono, Taketoshi; Nishijo, Hisao

    2013-11-19

    Snakes and their relationships with humans and other primates have attracted broad attention from multiple fields of study, but not, surprisingly, from neuroscience, despite the involvement of the visual system and strong behavioral and physiological evidence that humans and other primates can detect snakes faster than innocuous objects. Here, we report the existence of neurons in the primate medial and dorsolateral pulvinar that respond selectively to visual images of snakes. Compared with three other categories of stimuli (monkey faces, monkey hands, and geometrical shapes), snakes elicited the strongest, fastest responses, and the responses were not reduced by low spatial filtering. These findings integrate neuroscience with evolutionary biology, anthropology, psychology, herpetology, and primatology by identifying a neurobiological basis for primates' heightened visual sensitivity to snakes, and adding a crucial component to the growing evolutionary perspective that snakes have long shaped our primate lineage.

  12. Pulvinar neurons reveal neurobiological evidence of past selection for rapid detection of snakes

    Science.gov (United States)

    Van Le, Quan; Isbell, Lynne A.; Matsumoto, Jumpei; Nguyen, Minh; Hori, Etsuro; Maior, Rafael S.; Tomaz, Carlos; Tran, Anh Hai; Ono, Taketoshi; Nishijo, Hisao

    2013-01-01

    Snakes and their relationships with humans and other primates have attracted broad attention from multiple fields of study, but not, surprisingly, from neuroscience, despite the involvement of the visual system and strong behavioral and physiological evidence that humans and other primates can detect snakes faster than innocuous objects. Here, we report the existence of neurons in the primate medial and dorsolateral pulvinar that respond selectively to visual images of snakes. Compared with three other categories of stimuli (monkey faces, monkey hands, and geometrical shapes), snakes elicited the strongest, fastest responses, and the responses were not reduced by low spatial filtering. These findings integrate neuroscience with evolutionary biology, anthropology, psychology, herpetology, and primatology by identifying a neurobiological basis for primates’ heightened visual sensitivity to snakes, and adding a crucial component to the growing evolutionary perspective that snakes have long shaped our primate lineage. PMID:24167268

  13. Alterations of neuronal precursor cells in stages of human adult neurogenesis in heroin addicts.

    Science.gov (United States)

    Bayer, Ronny; Franke, Heike; Ficker, Christoph; Richter, Monique; Lessig, Rüdiger; Büttner, Andreas; Weber, Marco

    2015-11-01

    Adult neurogenesis has been shown to occur throughout life and different brain pathologies were demonstrated to be associated with altered neurogenesis. Here, an impact of heroin addiction on neurogenesis in humans is hypothesised. Post mortem hippocampal specimens of drug addicts with known heroin abuse and a group of non-addictive control subjects were analysed, using antibodies indicating different stages of neurogenesis. The subgranular zone of the dentate gyrus was examined qualitatively and quantitatively. The data indicate (i) a decreased number of neural precursor cells, (ii) accompanied by low rates of proliferation and (iii) a marked loss of dendritic trees in targeting cells in heroin fatalities. (iv) The age-dependent increase of differentiating cells in the healthy controls was not observed in the addicts. Additionally, double immunofluorescence labelling indicated the precursor nature of Musashi-1 positive cells in the human subgranular zone of the dentate gyrus. Present data firstly demonstrate the influence of drug addiction with known heroin abuse on different developmental stages of progenitors in the dentate gyrus. The patterns of antibody staining suggest a distinct inhibition of neurogenesis at the stage of neural precursor cells and revealed morphological changes in targeting cells in cases of heroin addicts as compared to healthy controls. These alterations could be considerable for memory and cognitive deficits as well as addictive behaviour in chronic drug abusers and may give rise to specific pro-neurogenic therapies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Chronic intermittent hypoxia-hypercapnia blunts heart rate responses and alters neurotransmission to cardiac vagal neurons.

    Science.gov (United States)

    Dyavanapalli, Jhansi; Jameson, Heather; Dergacheva, Olga; Jain, Vivek; Alhusayyen, Mona; Mendelowitz, David

    2014-07-01

    Patients with obstructive sleep apnoea experience chronic intermittent hypoxia-hypercapnia (CIHH) during sleep that elicit sympathetic overactivity and diminished parasympathetic activity to the heart, leading to hypertension and depressed baroreflex sensitivity. The parasympathetic control of heart rate arises from pre-motor cardiac vagal neurons (CVNs) located in nucleus ambiguus (NA) and dorsal motor nucleus of the vagus (DMNX). The mechanisms underlying diminished vagal control of heart rate were investigated by studying the changes in blood pressure, heart rate, and neurotransmission to CVNs evoked by acute hypoxia-hypercapnia (H-H) and CIHH. In vivo telemetry recordings of blood pressure and heart rate were obtained in adult rats during 4 weeks of CIHH exposure. Retrogradely labelled CVNs were identified in an in vitro brainstem slice preparation obtained from adult rats exposed either to air or CIHH for 4 weeks. Postsynaptic inhibitory or excitatory currents were recorded using whole cell voltage clamp techniques. Rats exposed to CIHH had increases in blood pressure, leading to hypertension, and blunted heart rate responses to acute H-H. CIHH induced an increase in GABAergic and glycinergic neurotransmission to CVNs in NA and DMNX, respectively; and a reduction in glutamatergic neurotransmission to CVNs in both nuclei. CIHH blunted the bradycardia evoked by acute H-H and abolished the acute H-H evoked inhibition of GABAergic transmission while enhancing glycinergic neurotransmission to CVNs in NA. These changes with CIHH inhibit CVNs and vagal outflow to the heart, both in acute and chronic exposures to H-H, resulting in diminished levels of cardioprotective parasympathetic activity to the heart as seen in OSA patients. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

  15. Light stimuli control neuronal migration by altering of insulin-like growth factor 1 (IGF-1) signaling.

    Science.gov (United States)

    Li, Ying; Komuro, Yutaro; Fahrion, Jennifer K; Hu, Taofang; Ohno, Nobuhiko; Fenner, Kathleen B; Wooton, Jessica; Raoult, Emilie; Galas, Ludovic; Vaudry, David; Komuro, Hitoshi

    2012-02-14

    The role of genetic inheritance in brain development has been well characterized, but little is known about the contributions of natural environmental stimuli, such as the effect of light-dark cycles, to brain development. In this study, we determined the role of light stimuli in neuronal cell migration to elucidate how environmental factors regulate brain development. We show that in early postnatal mouse cerebella, granule cell migration accelerates during light cycles and decelerates during dark cycles. Furthermore, cerebellar levels of insulin-like growth factor 1 (IGF-1) are high during light cycles and low during dark cycles. There are causal relationships between light-dark cycles, speed of granule cell migration, and cerebellar IGF-1 levels. First, changes in light-dark cycles result in corresponding changes in the fluctuations of both speed of granule cell migration and cerebellar IGF-1 levels. Second, in vitro studies indicate that exogenous IGF-1 accelerates the migration of isolated granule cells through the activation of IGF-1 receptors. Third, in vivo studies reveal that inhibiting the IGF-1 receptors decelerates granule cell migration during light cycles (high IGF-1 levels) but does not alter migration during dark cycles (low IGF-1 levels). In contrast, stimulating the IGF-1 receptors accelerates granule cell migration during dark cycles (low IGF-1 levels) but does not alter migration during light cycles (high IGF-1 levels). These results suggest that during early postnatal development light stimuli control granule cell migration by altering the activity of IGF-1 receptors through modification of cerebellar IGF-1 levels.

  16. Neurotransmission to parasympathetic cardiac vagal neurons in the brain stem is altered with left ventricular hypertrophy-induced heart failure.

    Science.gov (United States)

    Cauley, Edmund; Wang, Xin; Dyavanapalli, Jhansi; Sun, Ke; Garrott, Kara; Kuzmiak-Glancy, Sarah; Kay, Matthew W; Mendelowitz, David

    2015-10-01

    Hypertension, cardiac hypertrophy, and heart failure (HF) are widespread and debilitating cardiovascular diseases that affect nearly 23 million people worldwide. A distinctive hallmark of these cardiovascular diseases is autonomic imbalance, with increased sympathetic activity and decreased parasympathetic vagal tone. Recent device-based approaches, such as implantable vagal stimulators that stimulate a multitude of visceral sensory and motor fibers in the vagus nerve, are being evaluated as new therapeutic approaches for these and other diseases. However, little is known about how parasympathetic activity to the heart is altered with these diseases, and this lack of knowledge is an obstacle in the goal of devising selective interventions that can target and selectively restore parasympathetic activity to the heart. To identify the changes that occur within the brain stem to diminish the parasympathetic cardiac activity, left ventricular hypertrophy was elicited in rats by aortic pressure overload using a transaortic constriction approach. Cardiac vagal neurons (CVNs) in the brain stem that generate parasympathetic activity to the heart were identified with a retrograde tracer and studied using patch-clamp electrophysiological recordings in vitro. Animals with left cardiac hypertrophy had diminished excitation of CVNs, which was mediated both by an augmented frequency of spontaneous inhibitory GABAergic neurotransmission (with no alteration of inhibitory glycinergic activity) as well as a diminished amplitude and frequency of excitatory neurotransmission to CVNs. Opportunities to alter these network pathways and neurotransmitter receptors provide future targets of intervention in the goal to restore parasympathetic activity and autonomic balance to the heart in cardiac hypertrophy and other cardiovascular diseases. Copyright © 2015 the American Physiological Society.

  17. Promotion of non-rapid eye movement sleep and activation of reticular thalamic neurons by a novel MT2 melatonin receptor ligand.

    Science.gov (United States)

    Ochoa-Sanchez, Rafael; Comai, Stefano; Lacoste, Baptiste; Bambico, Francis Rodriguez; Dominguez-Lopez, Sergio; Spadoni, Gilberto; Rivara, Silvia; Bedini, Annalida; Angeloni, Debora; Fraschini, Franco; Mor, Marco; Tarzia, Giorgio; Descarries, Laurent; Gobbi, Gabriella

    2011-12-14

    Melatonin activates two brain G-protein coupled receptors, MT(1) and MT(2), whose differential roles in the sleep-wake cycle remain to be defined. The novel MT(2) receptor partial agonist, N-{2-[(3-methoxyphenyl) phenylamino] ethyl} acetamide (UCM765), is here shown to selectively promote non-rapid eye movement sleep (NREMS) in rats and mice. The enhancement of NREMS by UCM765 is nullified by the pharmacological blockade or genetic deletion of MT(2) receptors. MT(2), but not MT(1), knock-out mice show a decrease in NREMS compared to the wild strain. Immunohistochemical labeling reveals that MT(2) receptors are localized in sleep-related brain regions, and notably the reticular thalamic nucleus (Rt). Microinfusion of UCM765 in the Rt promotes NREMS, and its systemic administration induces an increase in firing and rhythmic burst activity of Rt neurons, which is blocked by the MT(2) antagonist 4-phenyl-2-propionamidotetralin. Since developing hypnotics that increase NREMS without altering sleep architecture remains a medical challenge, MT(2) receptors may represent a novel target for the treatment of sleep disorders.

  18. Whole brain-based analysis of regional white matter tract alterations in rare motor neuron diseases by diffusion tensor imaging.

    Science.gov (United States)

    Unrath, Alexander; Müller, Hans-Peter; Riecker, Axel; Ludolph, Albert C; Sperfeld, Anne-Dorte; Kassubek, Jan

    2010-11-01

    Different motor neuron disorders (MNDs) are mainly defined by the clinical presentation based on the predominance of upper or lower motor neuron impairment and the course of the disease. Magnetic resonance imaging (MRI) mostly serves as a tool to exclude other pathologies, but novel approaches such as diffusion tensor imaging (DTI) have begun to add information on the underlying pathophysiological processes of these disorders in vivo. The present study was designed to investigate three different rare MNDs, i.e., primary lateral sclerosis (PLS, N = 25), hereditary spastic paraparesis (HSP, N = 24), and X-linked spinobulbar muscular atrophy (X-SBMA, N = 20), by use of whole-brain-based DTI analysis in comparison with matched controls. This analysis of white matter (WM) impairment revealed widespread and characteristic patterns of alterations within the motor system with a predominant deterioration of the corticospinal tract (CST) in HSP and PLS patients according to the clinical presentation and also in patients with X-SBMA to a lesser degree, but also WM changes in projections to the limbic system and within distinct areas of the corpus callosum (CC), the latter both for HSP and PLS. In summary, DTI was able to define a characteristic WM pathoanatomy in motor and extra-motor brain areas, such as the CC and the limbic projectional system, for different MNDs via whole brain-based FA assessment and quantitative fiber tracking. Future advanced MRI-based investigations might help to provide a fingerprint-identification of MNDs. © 2010 Wiley-Liss, Inc.

  19. Medial prefrontal cortex neuronal activation and synaptic alterations after stress-induced reinstatement of palatable food seeking: a study using c-fos-GFP transgenic female rats.

    Science.gov (United States)

    Cifani, Carlo; Koya, Eisuke; Navarre, Brittany M; Calu, Donna J; Baumann, Michael H; Marchant, Nathan J; Liu, Qing-Rong; Khuc, Thi; Pickel, James; Lupica, Carl R; Shaham, Yavin; Hope, Bruce T

    2012-06-20

    Relapse to maladaptive eating habits during dieting is often provoked by stress and there is evidence for a role of ovarian hormones in stress responses and feeding. We studied the role of these hormones in stress-induced reinstatement of food seeking and medial prefrontal cortex (mPFC) neuronal activation in c-fos-GFP transgenic female rats, which express GFP in strongly activated neurons. Food-restricted ovariectomized or sham-operated c-fos-GFP rats were trained to lever-press for palatable food pellets. Subsequently, lever-pressing was extinguished and reinstatement of food seeking and mPFC neuronal activation was assessed after injections of the pharmacological stressor yohimbine (0.5-2 mg/kg) or pellet priming (1-4 noncontingent pellets). Estrous cycle effects on reinstatement were also assessed in wild-type rats. Yohimbine- and pellet-priming-induced reinstatement was associated with Fos and GFP induction in mPFC; both reinstatement and neuronal activation were minimally affected by ovarian hormones in both c-fos-GFP and wild-type rats. c-fos-GFP transgenic rats were then used to assess glutamatergic synaptic alterations within activated GFP-positive and nonactivated GFP-negative mPFC neurons following yohimbine-induced reinstatement of food seeking. This reinstatement was associated with reduced AMPA receptor/NMDA receptor current ratios and increased paired-pulse facilitation in activated GFP-positive but not GFP-negative neurons. While ovarian hormones do not appear to play a role in stress-induced relapse of food seeking in our rat model, this reinstatement was associated with unique synaptic alterations in strongly activated mPFC neurons. Our paper introduces the c-fos-GFP transgenic rat as a new tool to study unique synaptic changes in activated neurons during behavior.

  20. Medial prefrontal cortex neuronal activation and synaptic alterations after stress-induced reinstatement of palatable food seeking: a study using c-fos-GFP transgenic female rats

    Science.gov (United States)

    Cifani, Carlo; Koya, Eisuke; Navarre, Brittany M.; Calu, Donna J.; Baumann, Michael H.; Marchant, Nathan J.; Liu, Qing-Rong; Khuc, Thi; Pickel, James; Lupica, Carl R.; Shaham, Yavin; Hope, Bruce T.

    2012-01-01

    Relapse to maladaptive eating habits during dieting is often provoked by stress and there is evidence for a role of ovarian hormones in stress responses and feeding. We studied the role of these hormones in stress-induced reinstatement of food seeking and medial prefrontal cortex (mPFC) neuronal activation in c-fos-GFP transgenic female rats, which express green fluorescent protein (GFP) in strongly activated neurons. Food-restricted ovariectomized or sham-operated c-fos-GFP rats were trained to lever-press for palatable food pellets. Subsequently, lever-pressing was extinguished and reinstatement of food seeking and mPFC neuronal activation was assessed after injections of the pharmacological stressor yohimbine (0.5–2 mg/kg) or pellet priming (1–4 non-contingent pellets). Estrous cycle effects on reinstatement were also assessed in wild-type rats. Yohimbine- and pellet-priming-induced reinstatement was associated with Fos and GFP induction in mPFC; both reinstatement and neuronal activation were minimally affected by ovarian hormones in both c-fos-GFP and wild-type rats. c-fos-GFP transgenic rats were then used to assess glutamatergic synaptic alterations within activated GFP-positive and non-activated GFP-negative mPFC neurons following yohimbine-induced reinstatement of food seeking. This reinstatement was associated with reduced AMPAR/NMDAR current ratios and increased paired-pulse facilitation in activated GFP-positive but not GFP-negative neurons. Together, while ovarian hormones do not appear to play a role in stress-induced relapse of food seeking in our rat model, this reinstatement was associated with unique synaptic alterations in strongly activated mPFC neurons. Our paper introduces the c-fos-GFP transgenic rat as a new tool to study unique synaptic changes in activated neurons during behavior. PMID:22723688

  1. 17β-Estradiol alters the response of subfornical organ neurons that project to supraoptic nucleus to plasma angiotensin II and hypernatremia.

    Science.gov (United States)

    Ciriello, John; Roder, Stefanie

    2013-08-14

    This study was done in urethane anesthetized, ovariectomized (OVX) female rats that were either implanted or not implanted with silastic capsules containing17β-estradiol (E2) to investigate the effect of systemic changes in E2 on the discharge rate of subfornical organ (SFO) neurons that projected to supraoptic nucleus (SON) and responded to changes in plasma levels of angiotensin II (ANG II) or hypernatremia. Extracellular single unit recordings were made from 146 histologically verified single units in SFO. Intra-carotid infusions of ANG II excited ~57% of these neurons, whereas ~23% were excited by hypertonic NaCl. Basal discharge rate of neurons excited by ANG II or hypertonic NaCl was significantly lower in OVX+E2 rats compared to OVX only animals. The response of SFO neurons antidromically activated by SON stimulation to intra-carotid injections of ANG II or hypertonic NaCl was greater in the OVX only compared to the OVX+E2 rats. Intra-carotid injections of E2 in either group attenuated not only the basal discharge of these neurons, but also their response to ANG II or hypertonic NaCl. In all cases this inhibitory effect of E2 was blocked by an intra-carotid injection of the E2 receptor antagonist ICI-182780, although ICI-182780 did not alter the neuron's response to ANG II or hypertonic NaCl. Additionally, ICI-182780 in the OVX+E2 animals significantly raised the basal discharge of SFO neurons and their response to ANG II or hypertonic NaCl. These data indicate that E2 alters the response of SFO neurons to ANG II or NaCl that project to SON, and suggest that E2 functions in the female to regulate neurohypophyseal function in response to circulating ANG II and plasma hypernatremia. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Alteration of spontaneous neuronal activity within the salience network in partially remitted depression.

    Science.gov (United States)

    Liu, Chun-Hong; Ma, Xin; Song, Lu-Ping; Tang, Li-Rong; Jing, Bin; Zhang, Yu; Li, Feng; Zhou, Zhen; Fan, Jin; Wang, Chuan-Yue

    2015-03-02

    Of major depression patients, 29-66% show only partial remission on a single antidepressant trial. Such patients are characterized by residual depressive symptoms such as anhedonia, psychic anxiety, sleep disturbance, and cognitive dysfunction. Despite having a tremendous impact on outcomes such as future relapse, morbidity, and mortality, the neural mechanisms of partially remitted depression remain unclear. Using the amplitude of low-frequency fluctuations (ALFF) approach, we investigated the intrinsic neural oscillation alterations during resting state in partially remitted depression. A total of 23 partially remitted depression patients and 68 healthy controls underwent magnetic resonance imaging for functional imaging. We compared ALFF differences between groups as well as correlations between clinical measurements and ALFF in the brain regions showing significant group differences. Compared with healthy controls, partially remitted depression patients showed increased ALFF in the left ventral anterior insula, bilateral posterior insula, and bilateral supramarginal gyrus, and decreased ALFF in the left calcarine gyrus. A trend positive correlation between the number of depressive episodes and ALFF values was found in the right posterior insula in the partially remitted depression group. In addition, the ALFF in the right supramarginal gyrus were negatively correlated with Hamilton Depression Rating Scale scores. Consistent with the emerging theory of the role of the salience network in sensing the changes of homeostasis that contributes to partially remitted depression, the current findings suggest that the increased intrinsic neural oscillation of the insula is related to the refractoriness to treatment and may be an imaging marker for predicting future depression recurrence. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Membrane-bound glucocorticoid receptors on distinct nociceptive neurons as potential targets for pain control through rapid non-genomic effects.

    Science.gov (United States)

    Shaqura, Mohammed; Li, Xiongjuan; Al-Khrasani, Mahmoud; Shakibaei, Mehdi; Tafelski, Sascha; Fürst, Susanna; Beyer, Antje; Kawata, Mitsuhiro; Schäfer, Michael; Mousa, Shaaban A

    2016-12-01

    Glucocorticoids were long believed to primarily function through cytosolic glucocorticoid receptor (GR) activation and subsequent classical genomic pathways. Recently, however, evidence has emerged that suggests the presence of rapid non-genomic GR-dependent signaling pathways within the brain, though their existence in spinal and peripheral nociceptive neurons remains elusive. In this paper, we aim to systemically identify GR within the spinal cord and periphery, to verify their putative membrane location and to characterize possible G protein coupling and pain modulating properties. Double immunofluorescence confocal microscopy revealed that GR predominantly localized in peripheral peptidergic and non-peptidergic nociceptive C- and Aδ-neurons and existed only marginally in myelinated mechanoreceptive and proprioreceptive neurons. Within the spinal cord, GR predominantly localized in incoming presynaptic nociceptive neurons, in pre- and postsynaptic structures of the dorsal horn, as well as in microglia. GR saturation binding revealed that these receptors are linked to the cell membrane of sensory neurons and, upon activation, they trigger membrane targeted [(35)S]GTPγS binding, indicating G protein coupling to a putative receptor. Importantly, subcutaneous dexamethasone immediately and dose-dependently attenuated acute nociceptive behavior elicited in an animal model of formalin-induced pain hypersensitivity compared to naive rats. Overall, this study provides firm evidence for a novel neuronal mechanism of GR agonists that is rapid, non-genomic, dependent on membrane binding and G protein coupling, and acutely modulates nociceptive behavior, thus unraveling a yet unconsidered mechanism of pain relief. Copyright © 2016. Published by Elsevier Ltd.

  4. Bidirectional Anticipation of Future Osmotic Challenges by Vasopressin Neurons.

    Science.gov (United States)

    Mandelblat-Cerf, Yael; Kim, Angela; Burgess, Christian R; Subramanian, Siva; Tannous, Bakhos A; Lowell, Bradford B; Andermann, Mark L

    2017-01-04

    Ingestion of water and food are major hypo- and hyperosmotic challenges. To protect the body from osmotic stress, posterior pituitary-projecting, vasopressin-secreting neurons (VPpp neurons) counter osmotic perturbations by altering their release of vasopressin, which controls renal water excretion. Vasopressin levels begin to fall within minutes of water consumption, even prior to changes in blood osmolality. To ascertain the precise temporal dynamics by which water or food ingestion affect VPpp neuron activity, we directly recorded the spiking and calcium activity of genetically defined VPpp neurons. In states of elevated osmolality, water availability rapidly decreased VPpp neuron activity within seconds, beginning prior to water ingestion, upon presentation of water-predicting cues. In contrast, food availability following food restriction rapidly increased VPpp neuron activity within seconds, but only following feeding onset. These rapid and distinct changes in activity during drinking and feeding suggest diverse neural mechanisms underlying anticipatory regulation of VPpp neurons. Published by Elsevier Inc.

  5. Alteration of Nrp1 signaling at different stages of olfactory neuron maturation promotes glomerular shifts along distinct axes in the olfactory bulb.

    Science.gov (United States)

    Assens, Alexis; Dal Col, Julien A; Njoku, Anthony; Dietschi, Quentin; Kan, Chenda; Feinstein, Paul; Carleton, Alan; Rodriguez, Ivan

    2016-10-15

    Building the topographic map in the mammalian olfactory bulb is explained by a model based on two axes along which sensory neurons are guided: one dorsoventral and one anteroposterior. This latter axis relies on specific expression levels of Nrp1. To evaluate the role of this receptor in this process, we used an in vivo genetic approach to decrease or suppress Nrp1 in specific neuronal populations and at different time points during axonal targeting. We observed, in neurons that express the M71 or M72 odorant receptors, that Nrp1 inactivation leads to two distinct wiring alterations, depending on the time at which Nrp1 expression is altered: first, a surprising dorsal shift of the M71 and M72 glomeruli, which often fuse with their contralateral counterparts, and second the formation of anteriorized glomeruli. The two phenotypes are partly recapitulated in mice lacking the Nrp1 ligand Sema3A and in mice whose sensory neurons express an Nrp1 mutant unable to bind Sema3A. Using a mosaic conditional approach, we show that M71 axonal fibers can bypass the Nrp1 signals that define their target area, since they are hijacked and coalesce with Nrp1-deficient M71-expressing axons that target elsewhere. Together, these findings show drastically different axonal targeting outcomes dependent on the timing at which Nrp1/Sema3A signaling is altered. © 2016. Published by The Company of Biologists Ltd.

  6. Selenium suppresses glutamate-induced cell death and prevents mitochondrial morphological dynamic alterations in hippocampal HT22 neuronal cells.

    Science.gov (United States)

    Ma, Yan-Mei; Ibeanu, Gordon; Wang, Li-Yao; Zhang, Jian-Zhong; Chang, Yue; Dong, Jian-Da; Li, P Andy; Jing, Li

    2017-01-19

    Previous studies have indicated that selenium supplementation may be beneficial in neuroprotection against glutamate-induced cell damage, in which mitochondrial dysfunction is considered a major pathogenic feature. However, the exact mechanisms by which selenium protects against glutamate-provoked mitochondrial perturbation remain ambiguous. In this study glutamate exposed murine hippocampal neuronal HT22 cell was used as a model to investigate the underlying mechanisms of selenium-dependent protection against mitochondria damage. We find that glutamate-induced cytotoxicity was associated with enhancement of superoxide production, activation of caspase-9 and -3, increases of mitochondrial fission marker and mitochondrial morphological changes. Selenium significantly resolved the glutamate-induced mitochondria structural damage, alleviated oxidative stress, decreased Apaf-1, caspases-9 and -3 contents, and altered the autophagy process as observed by a decline in the ratio of the autophagy markers LC3-I and LC3-II. These findings suggest that the protection of selenium against glutamate stimulated cell damage of HT22 cells is associated with amelioration of mitochondrial dynamic imbalance.

  7. Fate of tetanus toxin bound to the surface of primary neurons in culture: evidence for rapid internalization.

    Science.gov (United States)

    Critchley, D R; Nelson, P G; Habig, W H; Fishman, P H

    1985-05-01

    We examined the nature of the tetanus toxin receptor in primary cultures of mouse spinal cord by ligand blotting techniques. Membrane components were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transferred to nitrocellulose sheets, which were overlaid with 125I-labeled tetanus toxin. The toxin bound only to material at or near the dye front, which was lost when the cells were delipidated before electrophoresis. Gangliosides purified from the lipid extract were separated by thin-layer chromatography and the chromatogram was overlaid with 125I-toxin. The toxin bound to gangliosides corresponding to GD1b and GT1b. Similar results were obtained with brain membranes; thus, gangliosides rather than glycoproteins appear to be the toxin receptors both in vivo and in neuronal cell cultures. To follow the fate of tetanus toxin bound to cultured neurons, we developed an assay to measure cell-surface and internalized toxin. Cells were incubated with tetanus toxin at 0 degree C, washed, and sequentially exposed to antitoxin and 125I-labeled protein A. Using this assay, we found that much of the toxin initially bound to cell surface disappeared rapidly when the temperature was raised to 37 degrees C but not when the cells were kept at 0 degree C. Some of the toxin was internalized and could only be detected by our treating the cells with Triton X-100 before adding anti-toxin. Experiments with 125I-tetanus toxin showed that a substantial amount of the toxin bound at 0 degree C dissociated into the medium upon warming of the cells. Using immunofluorescence, we confirmed that some of the bound toxin was internalized within 15 min and accumulated in discrete structures. These structures did not appear to be lysosomes, as the cell-associated toxin had a long half-life and 90% of the radioactivity released into the medium was precipitated by trichloroacetic acid. The rapid internalization of tetanus toxin into a subcellular compartment where it escapes

  8. A large increase of sour taste receptor cells in Skn-1-deficient mice does not alter the number of their sour taste signal-transmitting gustatory neurons.

    Science.gov (United States)

    Maeda, Naohiro; Narukawa, Masataka; Ishimaru, Yoshiro; Yamamoto, Kurumi; Misaka, Takumi; Abe, Keiko

    2017-05-01

    The connections between taste receptor cells (TRCs) and innervating gustatory neurons are formed in a mutually dependent manner during development. To investigate whether a change in the ratio of cell types that compose taste buds influences the number of innervating gustatory neurons, we analyzed the proportion of gustatory neurons that transmit sour taste signals in adult Skn-1a -/- mice in which the number of sour TRCs is greatly increased. We generated polycystic kidney disease 1 like 3-wheat germ agglutinin (pkd1l3-WGA)/Skn-1a +/+ and pkd1l3-WGA/Skn-1a -/- mice by crossing Skn-1a -/- mice and pkd1l3-WGA transgenic mice, in which neural pathways of sour taste signals can be visualized. The number of WGA-positive cells in the circumvallate papillae is 3-fold higher in taste buds of pkd1l3-WGA/Skn-1a -/- mice relative to pkd1l3-WGA/Skn-1a +/+ mice. Intriguingly, the ratio of WGA-positive neurons to P2X 2 -expressing gustatory neurons in nodose/petrosal ganglia was similar between pkd1l3-WGA/Skn-1a +/+ and pkd1l3-WGA/Skn-1a -/- mice. In conclusion, an alteration in the ratio of cell types that compose taste buds does not influence the number of gustatory neurons that transmit sour taste signals. Copyright © 2017. Published by Elsevier B.V.

  9. Inosine Alters Gene Expression and Axonal Projections in Neurons Contralateral to a Cortical Infarct and Improves Skilled Use of the Impaired Limb

    Science.gov (United States)

    Zai, Laila; Ferrari, Christina; Subbaiah, Sathish; Havton, Leif A.; Coppola, Giovanni; Strittmatter, Stephen; Irwin, Nina; Geschwind, Daniel; Benowitz, Larry I.

    2010-01-01

    Recovery after stroke and other types of brain injury is restricted in part by the limited ability of undamaged neurons to form compensatory connections. Inosine, a naturally occurring purine nucleoside, stimulates neurons to extend axons in culture and, in vivo, enhances the ability of undamaged neurons to form axon collaterals after brain damage. The molecular changes induced by inosine are unknown, as is the ability of inosine to restore complex functions associated with a specific cortical area. Using a unilateral injury model limited to the sensorimotor cortex, we show that inosine triples the number of corticospinal tract axons that project from the unaffected hemisphere and form synaptic bouton-like structures in the denervated half of the spinal cord. These changes correlate with improved recovery in animals’ ability to grasp and consume food pellets with the affected forepaw. Studies using laser-capture microdissection and microarray analysis show that inosine profoundly affects gene expression in corticospinal neurons contralateral to the injury. Inosine attenuates transcriptional changes caused by the stroke, while upregulating the expression of genes associated with axon growth and the complement cascade. Thus, inosine alters gene expression in neurons contralateral to a stroke, enhances the ability of these neurons to form connections on the denervated side of the spinal cord, and improves performance with the impaired limb. PMID:19553458

  10. Altered GABAA receptor-mediated synaptic transmission disrupts the firing of gonadotropin-releasing hormone neurons in male mice under conditions that mimic steroid abuse.

    Science.gov (United States)

    Penatti, Carlos A A; Davis, Matthew C; Porter, Donna M; Henderson, Leslie P

    2010-05-12

    Gonadotropin-releasing hormone (GnRH) neurons are the central regulators of reproduction. GABAergic transmission plays a critical role in pubertal activation of pulsatile GnRH secretion. Self-administration of excessive doses of anabolic androgenic steroids (AAS) disrupts reproductive function and may have critical repercussions for pubertal onset in adolescent users. Here, we demonstrate that chronic treatment of adolescent male mice with the AAS 17alpha-methyltestosterone significantly decreased action potential frequency in GnRH neurons, reduced the serum gonadotropin levels, and decreased testes mass. AAS treatment did not induce significant changes in GABAA receptor subunit mRNA levels or alter the amplitude or decay kinetics of GABAA receptor-mediated spontaneous postsynaptic currents (sPSCs) or tonic currents in GnRH neurons. However, AAS treatment significantly increased action potential frequency in neighboring medial preoptic area (mPOA) neurons and GABAA receptor-mediated sPSC frequency in GnRH neurons. In addition, physical isolation of the more lateral aspects of the mPOA from the medially localized GnRH neurons abrogated the AAS-induced increase in GABAA receptor-mediated sPSC frequency and the decrease in action potential firing in the GnRH cells. Our results indicate that AAS act predominantly on steroid-sensitive presynaptic neurons within the mPOA to impart significant increases in GABAA receptor-mediated inhibitory tone onto downstream GnRH neurons, resulting in diminished activity of these pivotal mediators of reproductive function. These AAS-induced changes in central GABAergic circuits of the forebrain may significantly contribute to the disruptive actions of these drugs on pubertal maturation and the development of reproductive competence in male steroid abusers.

  11. Prenatal stress alters the negative correlation between neuronal activation in limbic regions and behavioral responses in rats exposed to high and low anxiogenic environments.

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    Mairesse, Jérôme; Viltart, Odile; Salomé, Nicolas; Giuliani, Alessandro; Catalani, Assia; Casolini, Paola; Morley-Fletcher, Sara; Nicoletti, Ferdinando; Maccari, Stefania

    2007-08-01

    Behavioral adaptation to an anxiogenic environment involves the activity of various interconnected limbic regions, such as the amygdala, hippocampus and prefrontal cortex. Prenatal stress (PS) in rats affects the ability to cope with environmental challenges and alters brain plasticity, leading to long-lasting behavioral and neurobiological alterations. We examined in PS and control animals whether behavioral reactivity was correlated to neuronal activation by assessing Fos protein expression in limbic regions of rats exposed to a low or high anxiogenic environment (the closed and open arms of an elevated plus maze, respectively). A negative correlation was found between behavioral and neuronal activation, with a lower behavioral reactivity and a higher neuronal response observed in rats exposed to the more anxiogenic environment (the open arm) with respect to the less anxiogenic environment (the closed arm). Interestingly, the variation in the neurobehavioral response between the two arms of the maze was less pronounced in rats that had been subjected to PS. This study provides a remarkable example of how long-lasting changes in brain plasticity induced by PS affect the ability of limbic neurons to cope with anxiogenic stimuli of different strength.

  12. A mouse model of visual perceptual learning reveals alterations in neuronal coding and dendritic spine density in the visual cortex

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    Yan eWang

    2016-03-01

    Full Text Available Visual perceptual learning (VPL can improve spatial vision in normally sighted and visually impaired individuals. Although previous studies of humans and large animals have explored the neural basis of VPL, elucidation of the underlying cellular and molecular mechanisms remains a challenge. Owing to the advantages of molecular genetic and optogenetic manipulations, the mouse is a promising model for providing a mechanistic understanding of VPL. Here, we thoroughly evaluated the effects and properties of VPL on spatial vision in C57BL/6J mice using a two-alternative, forced-choice visual water task. Briefly, the mice underwent prolonged training at near the individual threshold of contrast or spatial frequency (SF for pattern discrimination or visual detection for 35 consecutive days. Following training, the contrast-threshold trained mice showed an 87% improvement in contrast sensitivity (CS and a 55% gain in visual acuity (VA. Similarly, the SF-threshold trained mice exhibited comparable and long-lasting improvements in VA and significant gains in CS over a wide range of SFs. Furthermore, learning largely transferred across eyes and stimulus orientations. Interestingly, learning could transfer from a pattern discrimination task to a visual detection task, but not vice versa. We validated that this VPL fully restored VA in adult amblyopic mice and old mice. Taken together, these data indicate that mice, as a species, exhibit reliable VPL. Intrinsic signal optical imaging revealed that mice with perceptual training had higher cut-off SFs in primary visual cortex (V1 than those without perceptual training. Moreover, perceptual training induced an increase in the dendritic spine density in layer 2/3 pyramidal neurons of V1. These results indicated functional and structural alterations in V1 during VPL. Overall, our VPL mouse model will provide a platform for investigating the neurobiological basis of VPL.

  13. Changes to dryland rainfall result in rapid moss mortality and altered soil fertility

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    Reed, Sasha C.; Coe, Kirsten K.; Sparks, Jed P.; Housman, David C.; Zelikova, Tamara J.; Belnap, Jayne

    2012-01-01

    Arid and semi-arid ecosystems cover ~40% of Earth’s terrestrial surface, but we know little about how climate change will affect these widespread landscapes. Like many drylands, the Colorado Plateau in southwestern United States is predicted to experience elevated temperatures and alterations to the timing and amount of annual precipitation. We used a factorial warming and supplemental rainfall experiment on the Colorado Plateau to show that altered precipitation resulted in pronounced mortality of the widespread moss Syntrichia caninervis. Increased frequency of 1.2 mm summer rainfall events reduced moss cover from ~25% of total surface cover to fertility. Mosses are important members in many dryland ecosystems and the community changes observed here reveal how subtle modifications to climate can affect ecosystem structure and function on unexpectedly short timescales. Moreover, mortality resulted from increased precipitation through smaller, more frequent events, underscoring the importance of precipitation event size and timing, and highlighting our inadequate understanding of relationships between climate and ecosystem function in drylands.

  14. Rapid Alterations in Perirenal Adipose Tissue Transcriptomic Networks with Cessation of Voluntary Running

    OpenAIRE

    Ruegsegger, Gregory N.; Company, Joseph M.; Toedebusch, Ryan G.; Roberts, Christian K.; Roberts, Michael D.; Booth, Frank W.

    2015-01-01

    In maturing rats, the growth of abdominal fat is attenuated by voluntary wheel running. After the cessation of running by wheel locking, a rapid increase in adipose tissue growth to a size that is similar to rats that have never run (i.e. catch-up growth) has been previously reported by our lab. In contrast, diet-induced increases in adiposity have a slower onset with relatively delayed transcriptomic responses. The purpose of the present study was to identify molecular pathways associated wi...

  15. Gene alterations at Drosophila inversion breakpoints provide prima facie evidence for natural selection as an explanation for rapid chromosomal evolution

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    Guillén Yolanda

    2012-02-01

    Full Text Available Abstract Background Chromosomal inversions have been pervasive during the evolution of the genus Drosophila, but there is significant variation between lineages in the rate of rearrangement fixation. D. mojavensis, an ecological specialist adapted to a cactophilic niche under extreme desert conditions, is a chromosomally derived species with ten fixed inversions, five of them not present in any other species. Results In order to explore the causes of the rapid chromosomal evolution in D. mojavensis, we identified and characterized all breakpoints of seven inversions fixed in chromosome 2, the most dynamic one. One of the inversions presents unequivocal evidence for its generation by ectopic recombination between transposon copies and another two harbor inverted duplications of non-repetitive DNA at the two breakpoints and were likely generated by staggered single-strand breaks and repair by non-homologous end joining. Four out of 14 breakpoints lay in the intergenic region between preexisting duplicated genes, suggesting an adaptive advantage of separating previously tightly linked duplicates. Four out of 14 breakpoints are associated with transposed genes, suggesting these breakpoints are fragile regions. Finally two inversions contain novel genes at their breakpoints and another three show alterations of genes at breakpoints with potential adaptive significance. Conclusions D. mojavensis chromosomal inversions were generated by multiple mechanisms, an observation that does not provide support for increased mutation rate as explanation for rapid chromosomal evolution. On the other hand, we have found a number of gene alterations at the breakpoints with putative adaptive consequences that directly point to natural selection as the cause of D. mojavensis rapid chromosomal evolution.

  16. Gene alterations at Drosophila inversion breakpoints provide prima facie evidence for natural selection as an explanation for rapid chromosomal evolution.

    Science.gov (United States)

    Guillén, Yolanda; Ruiz, Alfredo

    2012-02-01

    Chromosomal inversions have been pervasive during the evolution of the genus Drosophila, but there is significant variation between lineages in the rate of rearrangement fixation. D. mojavensis, an ecological specialist adapted to a cactophilic niche under extreme desert conditions, is a chromosomally derived species with ten fixed inversions, five of them not present in any other species. In order to explore the causes of the rapid chromosomal evolution in D. mojavensis, we identified and characterized all breakpoints of seven inversions fixed in chromosome 2, the most dynamic one. One of the inversions presents unequivocal evidence for its generation by ectopic recombination between transposon copies and another two harbor inverted duplications of non-repetitive DNA at the two breakpoints and were likely generated by staggered single-strand breaks and repair by non-homologous end joining. Four out of 14 breakpoints lay in the intergenic region between preexisting duplicated genes, suggesting an adaptive advantage of separating previously tightly linked duplicates. Four out of 14 breakpoints are associated with transposed genes, suggesting these breakpoints are fragile regions. Finally two inversions contain novel genes at their breakpoints and another three show alterations of genes at breakpoints with potential adaptive significance. D. mojavensis chromosomal inversions were generated by multiple mechanisms, an observation that does not provide support for increased mutation rate as explanation for rapid chromosomal evolution. On the other hand, we have found a number of gene alterations at the breakpoints with putative adaptive consequences that directly point to natural selection as the cause of D. mojavensis rapid chromosomal evolution.

  17. Gene alterations at Drosophila inversion breakpoints provide prima facie evidence for natural selection as an explanation for rapid chromosomal evolution

    Science.gov (United States)

    2012-01-01

    Background Chromosomal inversions have been pervasive during the evolution of the genus Drosophila, but there is significant variation between lineages in the rate of rearrangement fixation. D. mojavensis, an ecological specialist adapted to a cactophilic niche under extreme desert conditions, is a chromosomally derived species with ten fixed inversions, five of them not present in any other species. Results In order to explore the causes of the rapid chromosomal evolution in D. mojavensis, we identified and characterized all breakpoints of seven inversions fixed in chromosome 2, the most dynamic one. One of the inversions presents unequivocal evidence for its generation by ectopic recombination between transposon copies and another two harbor inverted duplications of non-repetitive DNA at the two breakpoints and were likely generated by staggered single-strand breaks and repair by non-homologous end joining. Four out of 14 breakpoints lay in the intergenic region between preexisting duplicated genes, suggesting an adaptive advantage of separating previously tightly linked duplicates. Four out of 14 breakpoints are associated with transposed genes, suggesting these breakpoints are fragile regions. Finally two inversions contain novel genes at their breakpoints and another three show alterations of genes at breakpoints with potential adaptive significance. Conclusions D. mojavensis chromosomal inversions were generated by multiple mechanisms, an observation that does not provide support for increased mutation rate as explanation for rapid chromosomal evolution. On the other hand, we have found a number of gene alterations at the breakpoints with putative adaptive consequences that directly point to natural selection as the cause of D. mojavensis rapid chromosomal evolution. PMID:22296923

  18. Wetland vegetation in Manzala lagoon, Nile Delta coast, Egypt: Rapid responses of pollen to altered nile hydrology and land use

    Science.gov (United States)

    Bernhardt, C.E.; Stanley, J.-D.; Horton, B.P.

    2011-01-01

    The pollen record in a sediment core from Manzala lagoon on the Nile delta coastal margin of Egypt, deposited from ca. AD 1860 to 1990, indicates rapid coastal wetland vegetation responses to two primary periods of human activity. These are associated with artificially altered Nile hydrologic regimes in proximal areas and distal sectors located to ???1200 km south of Manzala. Freshwater wetland plants that were dominant, such as Typha and Phragmites, decreased rapidly, whereas in the early 1900s, brackish water wetland species (e.g., Amaranthaceae) increased. This change occurred after closure of the Aswan Low Dam in 1902. The second major modification in the pollen record occurred in the early 1970s, after Aswan High Dam closure from 1965 to 1970, when Typha pollen abundance increased rapidly. Massive population growth occurred along the Nile during the 130 years represented by the core section. During this time, the total volume of lagoon water decreased because of conversion of wetland areas to agricultural land, and input of organic-rich sediment, sewage (municipal, agricultural, industrial), and fertilizer in Manzala lagoon increased markedly. Although the wetland plant community has continued to respond to increasingly intensified and varied human-induced pressures in proximal sectors, the two most marked changes in Manzala pollen best correlate with distal events (i.e., closure of the two dams at Aswan). The study also shows that the two major vegetation changes in Manzala lagoon each occurred less than 10 years after closure upriver of the Low and High dams that markedly altered the Nile regime from Upper Egypt to the coast. ?? 2011, the Coastal Education & Research Foundation (CERF).

  19. An insert-based enzymatic cell culture system to rapidly and reversibly induce hypoxia: investigations of hypoxia-induced cell damage, protein expression and phosphorylation in neuronal IMR-32 cells

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    Ying Huang

    2013-11-01

    Ischemia-reperfusion injury and tissue hypoxia are of high clinical relevance because they are associated with various pathophysiological conditions such as myocardial infarction and stroke. Nevertheless, the underlying mechanisms causing cell damage are still not fully understood, which is at least partially due to the lack of cell culture systems for the induction of rapid and transient hypoxic conditions. The aim of the study was to establish a model that is suitable for the investigation of cellular and molecular effects associated with transient and long-term hypoxia and to gain insights into hypoxia-mediated mechanisms employing a neuronal culture system. A semipermeable membrane insert system in combination with the hypoxia-inducing enzymes glucose oxidase and catalase was employed to rapidly and reversibly generate hypoxic conditions in the culture medium. Hydrogen peroxide assays, glucose measurements and western blotting were performed to validate the system and to evaluate the effects of the generated hypoxia on neuronal IMR-32 cells. Using the insert-based two-enzyme model, hypoxic conditions were rapidly induced in the culture medium. Glucose concentrations gradually decreased, whereas levels of hydrogen peroxide were not altered. Moreover, a rapid and reversible (onoff generation of hypoxia could be performed by the addition and subsequent removal of the enzyme-containing inserts. Employing neuronal IMR-32 cells, we showed that 3 hours of hypoxia led to morphological signs of cellular damage and significantly increased levels of lactate dehydrogenase (a biochemical marker of cell damage. Hypoxic conditions also increased the amounts of cellular procaspase-3 and catalase as well as phosphorylation of the pro-survival kinase Akt, but not Erk1/2 or STAT5. In summary, we present a novel framework for investigating hypoxia-mediated mechanisms at the cellular level. We claim that the model, the first of its kind, enables researchers to rapidly and

  20. Chronic ethanol exposure alters the levels, assembly, and cellular organization of the actin cytoskeleton and microtubules in hippocampal neurons in primary culture.

    Science.gov (United States)

    Romero, Ana M; Esteban-Pretel, Guillermo; Marín, María P; Ponsoda, Xavier; Ballestín, Raúl; Canales, Juan J; Renau-Piqueras, Jaime

    2010-12-01

    The organization and dynamics of microtubules (MTs) and the actin cytoskeleton are critical for the correct development and functions of neurons, including intracellular traffic and signaling. In vitro ethanol exposure impairs endocytosis, exocytosis, and nucleocytoplasmic traffic in astrocytes and alters endocytosis in cultured neurons. In astrocytes, these effects relate to changes in the organization and/or function of MTs and the actin cytoskeleton. To evaluate this possibility in hippocampal cultured neurons, we analyzed if chronic ethanol exposure affects the levels, assembly, and cellular organization of both cytoskeleton elements and the possible underlying mechanisms of these effects by morphological and biochemical methods. In the experiments described below, we provide the first evidence that chronic alcohol exposure decreases the amount of both filamentous actin and polymerized tubulin in neurons and that the number of MTs in dendrites lowers in treated cells. Alcohol also diminishes the MT-associated protein-2 levels, which mainly localizes in the somatodendritic compartment in neurons. Ethanol decreases the levels of total Rac, Cdc42, and RhoA, three small guanosine triphosphatases (GTPases) involved in the organization and dynamics of the actin cytoskeleton and MTs. Yet when alcohol decreases the levels of the active forms (GTP bound) of Rac1 and Cdc42, it does not affect the active form of RhoA. We also investigated the levels of several effector and regulator molecules of these GTPases to find that alcohol induces heterogeneous results. In conclusion, our results show that MT, actin cytoskeleton organization, and Rho GTPase signaling pathways are targets for the toxic effects of ethanol in neurons.

  1. Sleep alterations in mammals: did aquatic conditions inhibit rapid eye movement sleep?

    Science.gov (United States)

    Madan, Vibha; Jha, Sushil K

    2012-12-01

    Sleep has been studied widely in mammals and to some extent in other vertebrates. Higher vertebrates such as birds and mammals have evolved an inimitable rapid eye movement (REM) sleep state. During REM sleep, postural muscles become atonic and the temperature regulating machinery remains suspended. Although REM sleep is present in almost all the terrestrial mammals, the aquatic mammals have either radically reduced or completely eliminated REM sleep. Further, we found a significant negative correlation between REM sleep and the adaptation of the organism to live on land or in water. The amount of REM sleep is highest in terrestrial mammals, significantly reduced in semi-aquatic mammals and completely absent or negligible in aquatic mammals. The aquatic mammals are obligate swimmers and have to surface at regular intervals for air. Also, these animals live in thermally challenging environments, where the conductive heat loss is approximately ~90 times greater than air. Therefore, they have to be moving most of the time. As an adaptation, they have evolved unihemispheric sleep, during which they can rove as well as rest. A condition that immobilizes muscle activity and suspends the thermoregulatory machinery, as happens during REM sleep, is not suitable for these animals. It is possible that, in accord with Darwin's theory, aquatic mammals might have abolished REM sleep with time. In this review, we discuss the possibility of the intrinsic role of aquatic conditions in the elimination of REM sleep in the aquatic mammals.

  2. Increases in myocardial workload induced by rapid atrial pacing trigger alterations in global metabolism.

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    Aslan T Turer

    Full Text Available To determine whether increases in cardiac work lead to alterations in the plasma metabolome and whether such changes arise from the heart or peripheral organs.There is growing evidence that the heart influences systemic metabolism through endocrine effects and affecting pathways involved in energy homeostasis.Nineteen patients referred for cardiac catheterization were enrolled. Peripheral and selective coronary sinus (CS blood sampling was performed at serial timepoints following the initiation of pacing, and metabolite profiling was performed by liquid chromatography-mass spectrometry (LC-MS.Pacing-stress resulted in a 225% increase in the median rate·pressure product from baseline. Increased myocardial work induced significant changes in the peripheral concentration of 43 of 125 metabolites assayed, including large changes in purine [adenosine (+99%, p = 0.006, ADP (+42%, p = 0.01, AMP (+79%, p = 0.004, GDP (+69%, p = 0.003, GMP (+58%, p = 0.01, IMP (+50%, p = 0.03, xanthine (+61%, p = 0.0006], and several bile acid metabolites. The CS changes in metabolites qualitatively mirrored those in the peripheral blood in both timing and magnitude, suggesting the heart was not the major source of the metabolite release.Isolated increases in myocardial work can induce changes in the plasma metabolome, but these changes do not appear to be directly cardiac in origin. A number of these dynamic metabolites have known signaling functions. Our study provides additional evidence to a growing body of literature on metabolic 'cross-talk' between the heart and other organs.

  3. Alteration of Neuronal Excitability and Short-Term Synaptic Plasticity in the Prefrontal Cortex of a Mouse Model of Mental Illness.

    Science.gov (United States)

    Crabtree, Gregg W; Sun, Ziyi; Kvajo, Mirna; Broek, Jantine A C; Fénelon, Karine; McKellar, Heather; Xiao, Lan; Xu, Bin; Bahn, Sabine; O'Donnell, James M; Gogos, Joseph A

    2017-04-12

    Using a genetic mouse model that faithfully recapitulates a DISC1 genetic alteration strongly associated with schizophrenia and other psychiatric disorders, we examined the impact of this mutation within the prefrontal cortex. Although cortical layering, cytoarchitecture, and proteome were found to be largely unaffected, electrophysiological examination of the mPFC revealed both neuronal hyperexcitability and alterations in short-term synaptic plasticity consistent with enhanced neurotransmitter release. Increased excitability of layer II/III pyramidal neurons was accompanied by consistent reductions in voltage-activated potassium currents near the action potential threshold as well as by enhanced recruitment of inputs arising from superficial layers to layer V. We further observed reductions in both the paired-pulse ratios and the enhanced short-term depression of layer V synapses arising from superficial layers consistent with enhanced neurotransmitter release at these synapses. Recordings from layer II/III pyramidal neurons revealed action potential widening that could account for enhanced neurotransmitter release. Significantly, we found that reduced functional expression of the voltage-dependent potassium channel subunit K v 1.1 substantially contributes to both the excitability and short-term plasticity alterations that we observed. The underlying dysregulation of K v 1.1 expression was attributable to cAMP elevations in the PFC secondary to reduced phosphodiesterase 4 activity present in Disc1 deficiency and was rescued by pharmacological blockade of adenylate cyclase. Our results demonstrate a potentially devastating impact of Disc1 deficiency on neural circuit function, partly due to K v 1.1 dysregulation that leads to a dual dysfunction consisting of enhanced neuronal excitability and altered short-term synaptic plasticity. SIGNIFICANCE STATEMENT Schizophrenia is a profoundly disabling psychiatric illness with a devastating impact not only upon the

  4. Phase resetting of the mammalian circadian clock relies on a rapid shift of a small population of pacemaker neurons.

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    Jos H T Rohling

    Full Text Available The circadian pacemaker of the suprachiasmatic nuclei (SCN contains a major pacemaker for 24 h rhythms that is synchronized to the external light-dark cycle. In response to a shift in the external cycle, neurons of the SCN resynchronize with different pace. We performed electrical activity recordings of the SCN of rats in vitro following a 6 hour delay of the light-dark cycle and observed a bimodal electrical activity pattern with a shifted and an unshifted component. The shifted component was relatively narrow as compared to the unshifted component (2.2 h and 5.7 h, respectively. Curve fitting and simulations predicted that less than 30% of the neurons contribute to the shifted component and that their phase distribution is small. This prediction was confirmed by electrophysiological recordings of neuronal subpopulations. Only 25% of the neurons exhibited an immediate shift in the phase of the electrical activity rhythms, and the phases of the shifted subpopulations appeared significantly more synchronized as compared to the phases of the unshifted subpopulations (p<0.05. We also performed electrical activity recordings of the SCN following a 9 hour advance of the light-dark cycle. The phase advances induced a large desynchrony among the neurons, but consistent with the delays, only 19% of the neurons peaked at the mid of the new light phase. The data suggest that resetting of the central circadian pacemaker to both delays and advances is brought about by an initial shift of a relatively small group of neurons that becomes highly synchronized following a shift in the external cycle. The high degree of synchronization of the shifted neurons may add to the ability of this group to reset the pacemaker. The large desynchronization observed following advances may contribute to the relative difficulty of the circadian system to respond to advanced light cycles.

  5. Urinary bladder irritation alters efficacy of vagal stimulation on rostral medullary neurons in chronic T8 spinalized rats.

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    Kaddumi, Ezidin G; Hubscher, Charles H

    2007-07-01

    The presence of pelvic visceral inputs to neurons in the rostral medulla that are responsive to electrical stimulation of the abdominal branches of the vagus nerve (VAG-abd) was investigated in a complete chronic T8 spinal transection rat model. Using extracellular electrophysiological recordings from single medullary reticular formation (MRF) neurons, 371 neurons in 15 rats responsive to pinching the ear (search stimulus) were tested for somato-visceral and viscero-visceral convergent responses to stimulation of the following nerves/territories: VAG-abd, dorsal nerve of the penis, pelvic nerve, distention of urinary bladder and colon, penile stimulation, urethral infusion, and touch/pinch of the entire body surface. In addition to these mechanical and electrical stimuli, a chemical stimulus applied to the bladder was assessed as well. Of the total neurons examined, 205 were tested before and 166 tested beginning 20 min after application of a chemical irritant (2% acetic acid) to the urinary bladder (same rats used pre/post irritation). As with intact controls, many ear-responsive MRF neurons responded to the electrical stimulation of VAG-abd. Although MRF neuron responses failed to be evoked with direct (mechanical and electrical nerve) pelvic visceral stimuli, acute chemical irritation of the urinary bladder produced a significant increase in the number of MRF neurons responsive to stimulation of VAG-abd. The results of this study indicate a central effect that potentially relates to some of the generalized below level pelvic visceral sensations that have been documented in patients with complete spinal cord injury.

  6. Rapid State-Dependent Alteration in Kv3 Channel Availability Drives Flexible Synaptic Signaling Dependent on Somatic Subthreshold Depolarization.

    Science.gov (United States)

    Rowan, Matthew J M; Christie, Jason M

    2017-02-21

    In many neurons, subthreshold depolarization in the soma can transiently increase action-potential (AP)-evoked neurotransmission via analog-to-digital facilitation. The mechanisms underlying this form of short-term synaptic plasticity are unclear, in part, due to the relative inaccessibility of the axon to direct physiological interrogation. Using voltage imaging and patch-clamp recording from presynaptic boutons of cerebellar stellate interneurons, we observed that depolarizing somatic potentials readily spread into the axon, resulting in AP broadening, increased spike-evoked Ca(2+) entry, and enhanced neurotransmission strength. Kv3 channels, which drive AP repolarization, rapidly inactivated upon incorporation of Kv3.4 subunits. This leads to fast susceptibility to depolarization-induced spike broadening and analog facilitation independent of Ca(2+)-dependent protein kinase C signaling. The spread of depolarization into the axon was attenuated by hyperpolarization-activated currents (Ih currents) in the maturing cerebellum, precluding analog facilitation. These results suggest that analog-to-digital facilitation is tempered by development or experience in stellate cells. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. Rapid State-Dependent Alteration in Kv3 Channel Availability Drives Flexible Synaptic Signaling Dependent on Somatic Subthreshold Depolarization

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    Matthew J.M. Rowan

    2017-02-01

    Full Text Available In many neurons, subthreshold depolarization in the soma can transiently increase action-potential (AP-evoked neurotransmission via analog-to-digital facilitation. The mechanisms underlying this form of short-term synaptic plasticity are unclear, in part, due to the relative inaccessibility of the axon to direct physiological interrogation. Using voltage imaging and patch-clamp recording from presynaptic boutons of cerebellar stellate interneurons, we observed that depolarizing somatic potentials readily spread into the axon, resulting in AP broadening, increased spike-evoked Ca2+ entry, and enhanced neurotransmission strength. Kv3 channels, which drive AP repolarization, rapidly inactivated upon incorporation of Kv3.4 subunits. This leads to fast susceptibility to depolarization-induced spike broadening and analog facilitation independent of Ca2+-dependent protein kinase C signaling. The spread of depolarization into the axon was attenuated by hyperpolarization-activated currents (Ih currents in the maturing cerebellum, precluding analog facilitation. These results suggest that analog-to-digital facilitation is tempered by development or experience in stellate cells.

  8. Alterations in regional cerebral glucose metabolism across waking and non-rapid eye movement sleep in depression.

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    Nofzinger, Eric A; Buysse, Daniel J; Germain, Anne; Price, Julie C; Meltzer, Carolyn C; Miewald, Jean M; Kupfer, David J

    2005-04-01

    Depression is associated with sleep disturbances, including alterations in non-rapid eye movement (NREM) sleep. Non-rapid eye movement sleep is associated with decreases in frontal, parietal, and temporal cortex metabolic activity compared with wakefulness. To show that depressed patients would have less of a decrease than controls in frontal metabolism between waking and NREM sleep and to show that during NREM sleep, they would have increased activity in structures that promote arousal. Subjects completed electroencephalographic sleep and regional cerebral glucose metabolism assessments during both waking and NREM sleep using [(18)F]fluoro-2-deoxy-D-glucose positron emission tomography. General clinical research center. The study included 29 unmedicated patients who met the Structured Clinical Interview for DSM-IV criteria for current major depression and who had a score of 15 or greater on a 17-item Hamilton Rating Scale for Depression and 28 medically healthy subjects of comparable age and sex who were free of mental disorders. Electroencephalographic sleep and regional cerebral metabolism during waking and NREM sleep. Depressed patients showed smaller decreases than healthy subjects in relative metabolism in broad regions of the frontal, parietal, and temporal cortex from waking to NREM sleep. Depressed patients showed larger decreases than healthy subjects in relative metabolism in the left amygdala, anterior cingulate cortex, cerebellum, parahippocampal cortex, fusiform gyrus, and occipital cortex. However, in post hoc analyses, depressed patients showed hypermetabolism in these areas during both waking and NREM sleep. The smaller decrease in frontal metabolism from waking to NREM sleep in depressed patients is further evidence for a dynamic sleep-wake alteration in prefrontal cortex function in depression. Hypermetabolism in a ventral emotional neural system during waking in depressed patients persists into NREM sleep.

  9. Urethane anesthesia depresses activities of thalamocortical neurons and alters its response to nociception in terms of dual firing modes

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    Yeowool eHuh

    2013-10-01

    Full Text Available Anesthetics are often used to characterize the activity of single neurons in-vivo for its advantages such as reduced noise level and convenience in noxious stimulations. Of the anesthetics, urethane had been widely used in some thalamic studies under the assumption that sensory signals are still relayed to the thalamus under urethane anesthesia and that thalamic response would therefore reflect the response of the awake state. We tested whether this assumption stands by comparing thalamic activity in terms of tonic and burst firing modes during ‘the awake state’ or under ‘urethane anesthesia’ utilizing the extracellular single unit recording technique. First we have tested how thalamic relay neurons respond to the introduction of urethane and then tested how urethane influences thalamic discharges under formalin-induced nociception. Urethane significantly depressed overall firing rates of thalamic relay neurons, which was sustained despite the delayed increase of burst activity over the 4 hour recording period. Thalamic response to nociception under anesthesia was also similar overall except for the slight and transient increase of burst activity. Overall, results demonstrated that urethane suppresses the activity of thalamic relay neurons and that, despite the slight fluctuation of burst firing, formalin-induced nociception cannot significantly change the firing pattern of thalamic relay neurons that was caused by urethane.

  10. Altered posterior cingulate cortical cyctoarchitecture, but normal density of neurons and interneurons in the posterior cingulate cortex and fusiform gyrus in autism.

    Science.gov (United States)

    Oblak, Adrian L; Rosene, Douglas L; Kemper, Thomas L; Bauman, Margaret L; Blatt, Gene J

    2011-06-01

    Autism is a developmental disorder with prenatal origins, currently estimated to affect 1 in 91 children in the United States. Social-emotional deficits are a hallmark of autism and early neuropathology studies have indicated involvement of the limbic system. Imaging studies demonstrate abnormal activation of the posterior cingulate cortex (PCC), a component of the limbic system. Abnormal activation has also been noted in the fusiform gyrus (FFG), a region important for facial recognition and a key element in social interaction. A potential imbalance between excitatory and inhibitory interneurons in the cortex may contribute to altered information processing in autism. Furthermore, reduced numbers of GABA receptors have previously been reported in the autistic brain. Thionin-stained sections were used to qualitatively assess cytoarchitectonic patterning and quantitatively determine the density of neurons and immunohistochemistry was used to determine the densities of a subset of GABAergic interneurons utilizing parvalbumin-and calbindin-immunoreactivity. In autism, the PCC displayed altered cytoarchitecture with irregularly distributed neurons, poorly demarcated layers IV and V, and increased presence of white matter neurons. In contrast, no neuropathology was observed in the FFG. There was no significant difference in the density of thionin, parvalbumin, or calbindin interneurons in either region and there was a trend towards a reduced density of calbindin neurons in the PCC. This study highlights the presence of abnormal findings in the PCC, which appear to be developmental in nature and could affect the local processing of social-emotional behaviors as well as functioning of interrelated areas. Copyright © 2011, International Society for Autism Research, Wiley Periodicals, Inc.

  11. Downregulation of L1 perturbs neuronal migration and alters the expression of transcription factors in murine neocortex.

    Science.gov (United States)

    Kishimoto, Tomokazu; Itoh, Kyoko; Umekage, Masafumi; Tonosaki, Madoka; Yaoi, Takeshi; Fukui, Kenji; Lemmon, Vance P; Fushiki, Shinji

    2013-01-01

    L1 is a cell adhesion molecule associated with a spectrum of human neurological diseases, the most well-known being X-linked hydrocephalus. L1 knockout (L1-KO) mice have revealed a variety of functions of L1 that were crucial in brain development in different brain regions. However; the function of L1 in neuronal migration during cortical histogenesis remains to be clarified. We therefore investigated the corticogenesis of mouse embryos in which L1 molecules were knocked down in selected neurons, by employing in utero electroporation with shRNAs targeting L1 (L1 shRNA). Although more than 50% of the cells transfected with no small hairpin RNA (shRNA; monster green fluorescent protein: MGFP only) vector at embryonic day 13 (E13) reached the cortical plate at E16, significantly fewer (27%) cells transfected with L1 shRNA migrated to the same extent. At E17, 22% of cells transfected with the MGFP-only vector were found in the intermediate zone, and significantly more (34%) cells transfected with L1 shRNA remained in the same zone. Furthermore, the directions of the leading process of neurons transfected with L1 shRNA became more dispersed compared with cells with the MGFP-only vector. In addition, two transcription factors expressed in the neurons, Satb2 and Tbr1, were shown to be reduced or aberrantly expressed in neurons transfected with L1 shRNA. These observations suggest that L1 plays an important role in regulating the locomotion and orientation of migrating neurons and the expression of transcription factors during neocortical development that might partially be responsible for the abnormal tract formation seen in L1-KO mice. Copyright © 2012 Wiley Periodicals, Inc.

  12. Alterations to dendritic spine morphology, but not dendrite patterning, of cortical projection neurons in Tc1 and Ts1Rhr mouse models of Down syndrome.

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    Matilda A Haas

    Full Text Available Down Syndrome (DS is a highly prevalent developmental disorder, affecting 1/700 births. Intellectual disability, which affects learning and memory, is present in all cases and is reflected by below average IQ. We sought to determine whether defective morphology and connectivity in neurons of the cerebral cortex may underlie the cognitive deficits that have been described in two mouse models of DS, the Tc1 and Ts1Rhr mouse lines. We utilised in utero electroporation to label a cohort of future upper layer projection neurons in the cerebral cortex of developing mouse embryos with GFP, and then examined neuronal positioning and morphology in early adulthood, which revealed no alterations in cortical layer position or morphology in either Tc1 or Ts1Rhr mouse cortex. The number of dendrites, as well as dendrite length and branching was normal in both DS models, compared with wildtype controls. The sites of projection neuron synaptic inputs, dendritic spines, were analysed in Tc1 and Ts1Rhr cortex at three weeks and three months after birth, and significant changes in spine morphology were observed in both mouse lines. Ts1Rhr mice had significantly fewer thin spines at three weeks of age. At three months of age Tc1 mice had significantly fewer mushroom spines--the morphology associated with established synaptic inputs and learning and memory. The decrease in mushroom spines was accompanied by a significant increase in the number of stubby spines. This data suggests that dendritic spine abnormalities may be a more important contributor to cognitive deficits in DS models, rather than overall neuronal architecture defects.

  13. Rapid and efficient CRISPR/Cas9 gene inactivation in human neurons during human pluripotent stem cell differentiation and direct reprogramming.

    Science.gov (United States)

    Rubio, Alicia; Luoni, Mirko; Giannelli, Serena G; Radice, Isabella; Iannielli, Angelo; Cancellieri, Cinzia; Di Berardino, Claudia; Regalia, Giulia; Lazzari, Giovanna; Menegon, Andrea; Taverna, Stefano; Broccoli, Vania

    2016-11-18

    The CRISPR/Cas9 system is a rapid and customizable tool for gene editing in mammalian cells. In particular, this approach has widely opened new opportunities for genetic studies in neurological disease. Human neurons can be differentiated in vitro from hPSC (human Pluripotent Stem Cells), hNPCs (human Neural Precursor Cells) or even directly reprogrammed from fibroblasts. Here, we described a new platform which enables, rapid and efficient CRISPR/Cas9-mediated genome targeting simultaneously with three different paradigms for in vitro generation of neurons. This system was employed to inactivate two genes associated with neurological disorder (TSC2 and KCNQ2) and achieved up to 85% efficiency of gene targeting in the differentiated cells. In particular, we devised a protocol that, combining the expression of the CRISPR components with neurogenic factors, generated functional human neurons highly enriched for the desired genome modification in only 5 weeks. This new approach is easy, fast and that does not require the generation of stable isogenic clones, practice that is time consuming and for some genes not feasible.

  14. Hyperglycemia and high nitric oxide level induced oxidative stress in the brain and molecular alteration in the neurons and glial cells of laboratory mouse, Mus musculus.

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    Richa, Rashmi; Yadawa, Arun Kumar; Chaturvedi, Chandra Mohini

    2017-03-01

    Chronic hyperglycemia (glucotoxicity) is reported to have detrimental effects on various brain functions leading to neurodegenerative changes. However, the effect of hyperglycemia in combination with high nitric oxide (NO) level (reported to be increased during glucotoxicity), on brain functions is not clear yet. The present study was designed to investigate the effects of hyperglycemic drug Streptozotocin (STZ) and NO donor Sodium nitroprusside (SNP) on the brain of laboratory mouse, Mus musculus. Effects of these conditions were studied on the markers of oxidative stress, NF-κB signalling and the markers of neuronal and glial cell activation/inflammation. Results indicate increased level of MDA and altered antioxidant enzymes activity in both the treated groups compared to control but high levels of AGEs, AOPP and AR activity (markers of diabetic complications) were observed in STZ group only. On the other hand, while STZ group showed decreased IL-6 level, it was increased in SNP group but IFN-ϒ level increased in both the treated groups compared to control. Further, in addition to alterations in the expressions of iNOS, IKKβ, IKBα and NF-κB subunits (RelA-p65/RelB-p50) observed in the neurons and glial cells of different brain regions (hypothalamus, basolateral amygdala and cerebral cortex), enhanced expression of microglial CD11b and astrocytic GFAP was also found in both the treated groups compared to control. Present findings led us to conclude that both hyperglycemia and high NO level causes oxidative stress in addition to molecular alteration in the neurons and glial cells. It is suggested that high blood glucose and NO level induced oxidative stress may lead to neuroinflammation possibly via NF-κB signalling. Copyright © 2016. Published by Elsevier Ltd.

  15. Extended access methamphetamine decreases immature neurons in the hippocampus which results from loss and altered development of neural progenitors without altered dynamics of the S-phase of the cell cycle

    Science.gov (United States)

    Yuan, Clara J.; Quiocho, Jovy Marie D.; Kim, Airee; Wee, Sunmee; Mandyam, Chitra D.

    2011-01-01

    Methamphetamine addicts demonstrate impaired hippocampal-dependent cognitive function that could result from methamphetamine-induced maladaptive plasticity in the hippocampus. Reduced adult hippocampal neurogenesis observed in a rodent model of compulsive methamphetamine self-administration partially contributes to the maladaptive plasticity in the hippocampus. The potential mechanisms underlying methamphetamine-induced inhibition of hippocampal neurogenesis were identified in the present study. Key aspects of the cell cycle dynamics of hippocampal progenitors, including proliferation and neuronal development, were studied in rats that intravenously self-administered methamphetamine in a limited access (1 h/day: short access (ShA)-4 days and ShA-13 days) or extended access (6 h/day: long access (LgA)-4 days and LgA-13 days) paradigm. Immunohistochemical analysis of Ki-67 cells with 5-chloro-2’-deoxyuridine (CldU) demonstrated that LgA methamphetamine inhibited hippocampal proliferation by decreasing the proliferating pool of progenitors that are in the synthesis (S)-phase of the cell cycle. Double S-phase labeling with CldU and 5-iodo-2’-deoxyuridine (IdU) revealed that reduced S-phase cells were not due to alterations in the length of the S-phase. Further systematic analysis of Ki-67 cells with GFAP, Sox2, and DCX revealed that LgA methamphetamine-induced inhibition of hippocampal neurogenesis was attributable to impairment in the development of neuronal progenitors from preneuronal progenitors to immature neurons. Methamphetamine concomitantly increased hippocampal apoptosis, changes that were evident during the earlier days of self-administration. These findings demonstrate that methamphetamine self-administration initiates allostatic changes in adult neuroplasticity maintained by the hippocampus, including increased apoptosis, and altered dynamics of hippocampal neural progenitors. These data suggest that altered hippocampal plasticity by methamphetamine

  16. Rapid Response: To Scan or Not to Scan? The Utility of Noncontrast CT Head for Altered Mental Status.

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    Thacker, Purujit J; Sethi, Mansha; Sternlieb, Jonathan; Schneider, Doron; Naglak, Mary; Patel, Rajeshkumar R

    2018-01-17

    The aims of the study were the following: (1) to determine how often computed tomography (CT) scans of the head are obtained on rapid responses called for altered mental status (AMS), (2) to determine whether CT imaging of the head is required during all rapid responses called for AMS, (3) to determine which patients would benefit from CT scans of the head in this setting, (4) to note whether an adequate neurologic exam was documented, (5) to determine the cost of CT scans that did not change management, and (6) to examine the role of medications leading to AMS. The study was a retrospective chart review at Abington Jefferson Hospital. Data collected included the age, sex, time of rapid response, clinical condition of the patient, whether an arterial blood gas and blood glucose were done, and whether a neurological exam was documented in the resident's rapid response team note. The patient's medications were also reviewed. Computed tomography scan findings as well as changes made in a patient's care as a result of the scan were recorded. Any findings that did not lead to a change in management were considered a "negative" scan. Overall, 610 rapid responses were activated from January to August 2016. One hundred four (17.04%) of the total rapid responses were for AMS and 83 (79.8%) of these patients underwent noncontrast CT scan of the head. The mean (SD) age of the patients was 74.7 (13.6) years. A total of 56.6% were female. The most frequent clinical conditions documented at the time of rapid responses were noted as confused (33.7%, 28/83), either lethargic or unconscious (32.5%, 27/83), and concern for stroke (21.7%, 18/83). A total of 96.4% (80/83) of the CT scans done were negative for any acute changes. The three patients with positive scans (3/83) had a change in management as a result of the scans. If patients with symptoms concerning for stroke and unconscious patients are excluded, the total number of remaining patients is 56. Of these, zero patients had

  17. γ-Secretase modulators reduce endogenous amyloid β42 levels in human neural progenitor cells without altering neuronal differentiation.

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    D'Avanzo, Carla; Sliwinski, Christopher; Wagner, Steven L; Tanzi, Rudolph E; Kim, Doo Yeon; Kovacs, Dora M

    2015-08-01

    Soluble γ-secretase modulators (SGSMs) selectively decrease toxic amyloid β (Aβ) peptides (Aβ42). However, their effect on the physiologic functions of γ-secretase has not been tested in human model systems. γ-Secretase regulates fate determination of neural progenitor cells. Thus, we studied the impact of SGSMs on the neuronal differentiation of ReNcell VM (ReN) human neural progenitor cells (hNPCs). Quantitative PCR analysis showed that treatment of neurosphere-like ReN cell aggregate cultures with γ-secretase inhibitors (GSIs), but not SGSMs, induced a 2- to 4-fold increase in the expression of the neuronal markers Tuj1 and doublecortin. GSI treatment also induced neuronal marker protein expression, as shown by Western blot analysis. In the same conditions, SGSM treatment selectively reduced endogenous Aβ42 levels by ∼80%. Mechanistically, we found that Notch target gene expressions were selectively inhibited by a GSI, not by SGSM treatment. We can assert, for the first time, that SGSMs do not affect the neuronal differentiation of hNPCs while selectively decreasing endogenous Aβ42 levels in the same conditions. Our results suggest that our hNPC differentiation system can serve as a useful model to test the impact of GSIs and SGSMs on both endogenous Aβ levels and γ-secretase physiologic functions including endogenous Notch signaling. © FASEB.

  18. Deficiency of Serotonin in Raphe Neurons and Altered Behavioral Responses in Tryptophan Hydroxylase 2-Knockout Medaka (Oryzias latipes).

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    Ansai, Satoshi; Hosokawa, Hiroshi; Maegawa, Shingo; Naruse, Kiyoshi; Washio, Youhei; Sato, Kenji; Kinoshita, Masato

    2017-12-01

    Serotonin (5-hydroxytryptamine [5-HT]) is a bioactive monoamine that acts as a neurotransmitter in the central and peripheral nervous system of animals. Teleost fish species have serotonergic neurons in the raphe nuclei of the brainstem; however, the role of 5-HT in the raphe neurons in teleost fish remains largely unknown. Here, we established a medaka (Oryzias latipes) strain with targeted disruption of tryptophan hydroxylase 2 (tph2) gene that is involved in the 5-HT synthesis in the raphe nuclei. Immunohistochemistry and mass spectrometry analysis revealed that the homozygous mutants (tph2Δ13/Δ13) lacked the ability to synthesize 5-HT in the raphe neurons. To investigate the effects of 5-HT deficiency in adult behaviors, the mutant fish were subjected to five behavioral paradigms (diving, open-field, light-dark transition, mirror-biting, and two-fish social interaction). The homozygous mutation caused a longer duration of freezing response in all examined paradigms and reduced the number of entries to the top area in the diving test. In addition, the mutants exhibited a decreased number of mirror-biting in the males and an increased contact time in direct social interaction between the females. These results indicate that this tph2-knockout medaka serves as a good model to analyze the effects of 5-HT deficiency in the raphe neurons.

  19. Glycogen metabolism in brain and neurons - astrocytes metabolic cooperation can be altered by pre- and neonatal lead (Pb) exposure.

    Science.gov (United States)

    Baranowska-Bosiacka, Irena; Falkowska, Anna; Gutowska, Izabela; Gąssowska, Magdalena; Kolasa-Wołosiuk, Agnieszka; Tarnowski, Maciej; Chibowska, Karina; Goschorska, Marta; Lubkowska, Anna; Chlubek, Dariusz

    2017-09-01

    Lead (Pb) is an environmental neurotoxin which particularly affects the developing brain but the molecular mechanism of its neurotoxicity still needs clarification. The aim of this paper was to examine whether pre- and neonatal exposure to Pb (concentration of Pb in rat offspring blood below the "threshold level") may affect the brain's energy metabolism in neurons and astrocytes via the amount of available glycogen. We investigated the glycogen concentration in the brain, as well as the expression of the key enzymes involved in glycogen metabolism in brain: glycogen synthase 1 (Gys1), glycogen phosphorylase (PYGM, an isoform active in astrocytes; and PYGB, an isoform active in neurons) and phosphorylase kinase β (PHKB). Moreover, the expression of connexin 43 (Cx43) was evaluated to analyze whether Pb poisoning during the early phase of life may affect the neuron-astrocytes' metabolic cooperation. This work shows for the first time that exposure to Pb in early life can impair brain energy metabolism by reducing the amount of glycogen and decreasing the rate of its metabolism. This reduction in brain glycogen level was accompanied by a decrease in Gys1 expression. We noted a reduction in the immunoreactivity and the gene expression of both PYGB and PYGM isoform, as well as an increase in the expression of PHKB in Pb-treated rats. Moreover, exposure to Pb induced decrease in connexin 43 immunoexpression in all the brain structures analyzed, both in astrocytes as well as in neurons. Our data suggests that exposure to Pb in the pre- and neonatal periods results in a decrease in the level of brain glycogen and a reduction in the rate of its metabolism, thereby reducing glucose availability, which as a further consequence may lead to the impairment of brain energy metabolism and the metabolic cooperation between neurons and astrocytes. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Glycine receptor in rat hippocampal and spinal cord neurons as a molecular target for rapid actions of 17-β-estradiol

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    Liu Chun-Feng

    2009-01-01

    Full Text Available Abstract Glycine receptors (GlyRs play important roles in regulating hippocampal neural network activity and spinal nociception. Here we show that, in cultured rat hippocampal (HIP and spinal dorsal horn (SDH neurons, 17-β-estradiol (E2 rapidly and reversibly reduced the peak amplitude of whole-cell glycine-activated currents (IGly. In outside-out membrane patches from HIP neurons devoid of nuclei, E2 similarly inhibited IGly, suggesting a non-genomic characteristic. Moreover, the E2 effect on IGly persisted in the presence of the calcium chelator BAPTA, the protein kinase inhibitor staurosporine, the classical ER (i.e. ERα and ERβ antagonist tamoxifen, or the G-protein modulators, favoring a direct action of E2 on GlyRs. In HEK293 cells expressing various combinations of GlyR subunits, E2 only affected the IGly in cells expressing α2, α2β or α3β subunits, suggesting that either α2-containing or α3β-GlyRs mediate the E2 effect observed in neurons. Furthermore, E2 inhibited the GlyR-mediated tonic current in pyramidal neurons of HIP CA1 region, where abundant GlyR α2 subunit is expressed. We suggest that the neuronal GlyR is a novel molecular target of E2 which directly inhibits the function of GlyRs in the HIP and SDH regions. This finding may shed new light on premenstrual dysphoric disorder and the gender differences in pain sensation at the CNS level.

  1. A teleost androgen promotes development of primary ovarian follicles in coho salmon and rapidly alters the ovarian transcriptome.

    Science.gov (United States)

    Monson, Christopher; Forsgren, Kristy; Goetz, Giles; Harding, Louisa; Swanson, Penny; Young, Graham

    2017-11-01

    Recent studies using several teleost models have revealed that androgens increase the size of previtellogenic (primary and/or early secondary) ovarian follicles. To explore our hypothesis that androgens drive the development of primary follicles into early secondary follicles, and to determine the mechanisms underlying these androgenic effects, we exposed juvenile coho salmon to near-physiological and relatively sustained levels of the nonaromatizable androgen 11-ketotestosterone (11-KT). This resulted in significant growth of primary ovarian follicles after 10 and 20 days, with follicles after 20 days displaying a morphological phenotype characteristic of early secondary follicles (presence of cortical alveoli). Utilizing the same experimental approach, we then analyzed how 11-KT rapidly altered the ovarian transcriptome after 1 and 3 days of treatment. RNA-Seq analysis revealed that 69 (day 1) and 1,022 (day 3) contiguous sequences (contigs) were differentially expressed relative to controls. The differentially expressed contigs mapped to genes including those encoding proteins involved in gonadotropin, steroid hormone, and growth factor signaling, and in cell and ovarian development, including genes with putative androgen-response elements. Biological functions and canonical pathways identified as potentially altered by 11-KT include those involved in ovarian development, tissue differentiation and remodeling, and lipid metabolism. We conclude that androgens play a major role in stimulating primary ovarian follicle development and the transition into secondary growth. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Na+ Influx Induced by New Antimalarials Causes Rapid Alterations in the Cholesterol Content and Morphology of Plasmodium falciparum.

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    Sudipta Das

    2016-05-01

    Full Text Available Among the several new antimalarials discovered over the past decade are at least three clinical candidate drugs, each with a distinct chemical structure, that disrupt Na+ homeostasis resulting in a rapid increase in intracellular Na+ concentration ([Na+]i within the erythrocytic stages of Plasmodium falciparum. At present, events triggered by Na+ influx that result in parasite demise are not well-understood. Here we report effects of two such drugs, a pyrazoleamide and a spiroindolone, on intraerythrocytic P. falciparum. Within minutes following the exposure to these drugs, the trophozoite stage parasite, which normally contains little cholesterol, was made permeant by cholesterol-dependent detergents, suggesting it acquired a substantial amount of the lipid. Consistently, the merozoite surface protein 1 and 2 (MSP1 and MSP2, glycosylphosphotidylinositol (GPI-anchored proteins normally uniformly distributed in the parasite plasma membrane, coalesced into clusters. These alterations were not observed following drug treatment of P. falciparum parasites adapted to grow in a low [Na+] growth medium. Both cholesterol acquisition and MSP1 coalescence were reversible upon the removal of the drugs, implicating an active process of cholesterol exclusion from trophozoites that we hypothesize is inhibited by high [Na+]i. Electron microscopy of drug-treated trophozoites revealed substantial morphological changes normally seen at the later schizont stage including the appearance of partial inner membrane complexes, dense organelles that resemble "rhoptries" and apparent nuclear division. Together these results suggest that [Na+]i disruptor drugs by altering levels of cholesterol in the parasite, dysregulate trophozoite to schizont development and cause parasite demise.

  3. Rapid eye movement sleep loss induces neuronal apoptosis in the rat brain by noradrenaline acting on alpha 1-adrenoceptor and by triggering mitochondrial intrinsic pathway

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    Bindu I Somarajan

    2016-03-01

    Full Text Available Many neurodegenerative disorders are associated with rapid eye movement sleep (REMS-loss, however the mechanism was unknown. As REMS-loss elevates noradrenaline (NA level in the brain as well as induces neuronal apoptosis and degeneration, in this study we have delineated the intracellular molecular pathway involved in REMS deprivation (REMSD associated NA-induced neuronal apoptosis. Rats were REMS deprived for 6 days by the classical flower-pot method, suitable controls were conducted and the effects on apoptosis markers evaluated. Further, the role of NA was studied by one, intraperitoneal (i.p. injection of NA-ergic alpha1-adrenoceptor antagonist prazosin (PRZ and two, by down-regulation of NA synthesis in locus coeruleus (LC neurons by local microinjection of tyrosine hydroxylase siRNA (TH-siRNA. Immunoblot estimates showed that the expressions of pro-apoptotic proteins viz. Bcl2-associated death promoter (BAD protein, apoptotic protease activating factor-1 (Apaf-1, cytochrome c, caspase9, caspase3 were elevated in the REMS-deprived rat brains, while caspase8 level remained unaffected; PRZ treatment did not allow elevation of these pro-apoptotic factors. Further, REMSD increased cytochrome c expression, which was prevented if the NA synthesis from the LC neurons was blocked by microinjection of TH-siRNA in vivo into the LC during REMSD in freely moving normal rats. Mitochondrial damage was re-confirmed by transmission electron microscopy (TEM, which showed distinctly swollen mitochondria with disintegrated cristae, chromosomal condensation and clumping along the nuclear membrane and all these changes were prevented in PRZ treated rats. Combining findings of this study along with earlier reports we propose that upon REMSD NA level increases in the brain as the LC NA-ergic REM-OFF neurons do not cease firing and TH is up-regulated in those neurons. This elevated NA acting on alpha1-adrenoceptors damages mitochondria causing release of

  4. Altered Levels of Visinin-Like Protein 1 Correspond to Regional Neuronal Loss in Alzheimer Disease and Frontotemporal Lobar Degeneration.

    Science.gov (United States)

    Kirkwood, Caitlin M; MacDonald, Matthew L; Schempf, Tadhg A; Vatsavayi, Anil V; Ikonomovic, Milos D; Koppel, Jeremy L; Ding, Ying; Sun, Mai; Kofler, Julia K; Lopez, Oscar L; Yates, Nathan A; Sweet, Robert A

    2016-02-01

    Recent studies have implicated the neuronal calcium-sensing protein visinin-like 1 protein (Vilip-1) as a peripheral biomarker in Alzheimer disease (AD), but little is known about expression of Vilip-1 in the brains of patients with AD. We used targeted and quantitative mass spectrometry to measure Vilip-1 peptide levels in the entorhinal cortex (ERC) and the superior frontal gyrus (SF) from cases with early to moderate stage AD, frontotemporal lobar degeneration (FTLD), and cognitively and neuropathologically normal elderly controls. We found that Vilip-1 levels were significantly lower in the ERC, but not in SF, of AD subjects compared to normal controls. In FTLD cases, Vilip-1 levels in the SF were significantly lower than in normal controls. These findings suggest a unique role for cerebrospinal fluid Vilip-1 as a biomarker of ERC neuron loss in AD.

  5. Curcuma treatment prevents cognitive deficit and alteration of neuronal morphology in the limbic system of aging rats.

    Science.gov (United States)

    Vidal, Blanca; Vázquez-Roque, Rubén A; Gnecco, Dino; Enríquez, Raúl G; Floran, Benjamin; Díaz, Alfonso; Flores, Gonzalo

    2017-03-01

    Curcuma is a natural compound that has shown neuroprotective properties, and has been reported to prevent aging and improve memory. While the mechanism(s) underlying these effects are unclear, they may be related to increases in neural plasticity. Morphological changes have been reported in neuronal dendrites in the limbic system in animals and elderly humans with cognitive impairment. In this regard, there is a need to use alternative therapies that delay the onset of morphologies and behavioral characteristics of aging. Therefore, the objective of this study was to evaluate the effect of curcuma on cognitive processes and dendritic morphology of neurons in the prefrontal cortex (PFC), the CA1 and CA3 regions of the dorsal hippocampus, the dentate gyrus, and the basolateral amygdala (BLA) of aged rats. 18-month-old rats were administered curcuma (100 mg/kg) daily for 60 days. After treatment, recognition memory was assessed using the novel object recognition test. Curcuma-treated rats showed a significant increase in the exploration quotient. Dendritic morphology was assessed by Golgi-Cox staining and followed by Sholl analysis. Curcuma-treated rats showed a significant increase in dendritic spine density and dendritic length in pyramidal neurons of the PFC, the CA1 and CA3, and the BLA. The preservation of dendritic morphology was positively correlated with cognitive improvements. Our results suggest that curcuma induces modification of dendritic morphology in the aforementioned regions. These changes may explain how curcuma slows the aging process that has already begun in these animals, preventing deterioration in neuronal morphology of the limbic system and recognition memory. © 2016 Wiley Periodicals, Inc.

  6. Cisplatin alters the function and expression of N-type voltage-gated calcium channels in the absence of morphological damage of sensory neurons.

    Science.gov (United States)

    Leo, Markus; Schmitt, Linda-Isabell; Jastrow, Holger; Thomale, Jürgen; Kleinschnitz, Christoph; Hagenacker, Tim

    2017-01-01

    Platinum-based chemotherapeutic agents, such as cisplatin, are still frequently used for treating various types of cancer. Besides its high effectiveness, cisplatin has several serious side effects. One of the most common side effects is dorsal root ganglion (DRG) neurotoxicity. However, the mechanisms underlying this neurotoxicity are still unclear and controversially discussed. Cisplatin-mediated modulation of voltage-gated calcium channels (VGCCs) in the DRG neurons has been shown to alter intracellular calcium homeostasis, a process critical for the induction of neurotoxicity. Using the whole-cell patch-clamp technique, immunostaining, behavioural experiments and electron microscopy (EM) of rat DRGs, we here demonstrate that cisplatin-induced neurotoxicity is due to functional alteration of VGCC, but not due to morphological damage. In vitro application of cisplatin (0.5 µM) increased N-type VGCC currents ( ICa(V)) in small DRG neurons. Repetitive in vivo administration of cisplatin (1.5 mg/kg, cumulative 12 mg/kg) increased the protein level of N-type VGCC over 26 days, with the protein level being increased for at least 14 days after the final cisplatin administration. Behavioural studies revealed that N-type VGCCs are crucial for inducing symptoms of cisplatin-related neuropathic pain, such as thermal and mechanical hyperalgesia. EM and histology showed no evidence of any structural damage, apoptosis or necrosis in DRG cells after cisplatin exposure for 26 days. Furthermore, no nuclear DNA damage in sensory neurons was observed. Here, we provide evidence for a mainly functionally driven induction of neuropathic pain by cisplatin.

  7. Antinociceptive effect of botulinum toxin A involves alterations in AMPA receptor expression and glutamate release in spinal dorsal horn neurons.

    Science.gov (United States)

    Hong, Bin; Yao, LingLing; Ni, Linhui; Wang, Li; Hu, XingYue

    2017-08-15

    The use of botulinum toxin A (BTX-A) for various clinical therapeutic applications is increasing. It is widely believed that peripheral therapeutic or toxic effects of BTX-A are exclusively mediated by SNAP-25 cleavage. There is growing evidence of long-distance retrograde axonal transport of BTX-A on entering the central nervous system, subsequent to a local injection of the toxin. However, the prevalence of central antinociceptive effects after BTX-A peripheral application and its underlying mechanisms are unclear. Our results show that (1) BTX-A can undergo retrograde axonal transport to the dorsal horn after peripheral application; (2) Peripheral pretreatment with BTX-A decreases the expression and function of AMPA receptors in the spinal cord dorsal horn neurons; (3) Peripheral pretreatment with BTX-A does not change basal glutamate release, but decreases the effect of formalin-evoked release of glutamate in spinal cord dorsal horn neurons. These results suggest that peripheral application of BTX-A can change AMPA receptor expression in, and glutamate release from, spinal dorsal horn neurons, which may have significance in its central antinociceptive effects. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. TrkB gene transfer does not alter hippocampal neuronal loss and cognitive deficits following traumatic brain injury in mice.

    Science.gov (United States)

    Conte, Valeria; Raghupathi, Ramesh; Watson, Deborah J; Fujimoto, Scott; Royo, Nicolas C; Marklund, Niklas; Stocchetti, Nino; McIntosh, Tracy K

    2008-01-01

    The ability of brain-derived neurotrophic factor (BDNF) to attenuate secondary damage and influence behavioral outcome after experimental traumatic brain injury (TBI) remains controversial. Because TBI can result in decreased expression of the trkB receptor, thereby preventing BDNF from exerting potential neuroprotective effects, the contribution of both BDNF and its receptor trkB to hippocampal neuronal loss and cognitive dysfunction were evaluated. Full-length trkB was overexpressed in the left hippocampus of adult C57Bl/6 mice using recombinant adeno-associated virus serotype 2/5 (rAAV 2/5). EGFP (enhanced green fluorescent protein) expression was present at two weeks after AAV-EGFP injection and remained sustained up to four weeks after the injection. At 2 weeks following gene transduction, mice were subjected to parasagittal controlled cortical impact (CCI) brain injury, followed by either BDNF or PBS infusion into the hippocampus. No differences were observed in learning ability at two weeks post-injury or in motor function from 48 hours to two weeks among treatment groups. The number of surviving pyramidal neurons in the CA2-CA3 region of the hippocampus was also not different among treatment groups. These data suggest that neither overexpression of trkB, BNDF infusion or their combination affects neuronal survival or behavioral outcome following experimental TBI in mice.

  9. Deficits in the activity of presynaptic γ-aminobutyric acid type B receptors contribute to altered neuronal excitability in fragile X syndrome.

    Science.gov (United States)

    Kang, Ji-Yong; Chadchankar, Jayashree; Vien, Thuy N; Mighdoll, Michelle I; Hyde, Thomas M; Mather, Robert J; Deeb, Tarek Z; Pangalos, Menelas N; Brandon, Nicholas J; Dunlop, John; Moss, Stephen J

    2017-04-21

    The behavioral and anatomical deficits seen in fragile X syndrome (FXS) are widely believed to result from imbalances in the relative strengths of excitatory and inhibitory neurotransmission. Although modified neuronal excitability is thought to be of significance, the contribution that alterations in GABAergic inhibition play in the pathophysiology of FXS are ill defined. Slow sustained neuronal inhibition is mediated by γ-aminobutyric acid type B (GABA B ) receptors, which are heterodimeric G-protein-coupled receptors constructed from R1a and R2 or R1b and R2 subunits. Via the activation of G i/o , they limit cAMP accumulation, diminish neurotransmitter release, and induce neuronal hyperpolarization. Here we reveal that selective deficits in R1a subunit expression are seen in Fmr1 knock-out mice (KO) mice, a widely used animal model of FXS, but the levels of the respective mRNAs were unaffected. Similar trends of R1a expression were seen in a subset of FXS patients. GABA B receptors (GABA B Rs) exert powerful pre- and postsynaptic inhibitory effects on neurotransmission. R1a-containing GABA B Rs are believed to mediate presynaptic inhibition in principal neurons. In accordance with this result, deficits in the ability of GABA B Rs to suppress glutamate release were seen in Fmr1-KO mice. In contrast, the ability of GABA B Rs to suppress GABA release and induce postsynaptic hyperpolarization was unaffected. Significantly, this deficit contributes to the pathophysiology of FXS as the GABA B R agonist ( R )-baclofen rescued the imbalances between excitatory and inhibitory neurotransmission evident in Fmr1-KO mice. Collectively, our results provided evidence that selective deficits in the activity of presynaptic GABA B Rs contribute to the pathophysiology of FXS. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Rapid recovery and altered neurochemical dependence of locomotor central pattern generation following lumbar neonatal spinal cord injury.

    Science.gov (United States)

    Züchner, Mark; Kondratskaya, Elena; Sylte, Camilla B; Glover, Joel C; Boulland, Jean-Luc

    2018-01-15

    Spinal compression injury targeted to the neonatal upper lumbar spinal cord, the region of highest hindlimb locomotor rhythmogenicity, leads to an initial paralysis of the hindlimbs. Behavioural recovery is evident within a few days and approaches normal function within about 3 weeks. Fictive locomotion in the isolated injured spinal cord cannot be elicited by a neurochemical cocktail containing NMDA, dopamine and serotonin 1 day post-injury, but can 3 days post-injury as readily as in the uninjured spinal cord. Low frequency coordinated rhythmic activity can be elicited in the isolated uninjured spinal cord by NMDA + dopamine (without serotonin), but not in the isolated injured spinal cord. In both the injured and uninjured spinal cord, eliciting bona fide fictive locomotion requires the additional presence of serotonin. Following incomplete compression injury in the thoracic spinal cord of neonatal mice 1 day after birth (P1), we previously reported that virtually normal hindlimb locomotor function is recovered within about 3 weeks despite substantial permanent thoracic tissue loss. Here, we asked whether similar recovery occurs following lumbar injury that impacts more directly on the locomotor central pattern generator (CPG). As in thoracic injuries, lumbar injuries caused about 90% neuronal loss at the injury site and increased serotonergic innervation below the injury. Motor recovery was slower after lumbar than thoracic injury, but virtually normal function was attained by P25 in both cases. Locomotor CPG status was tested by eliciting fictive locomotion in isolated spinal cords using a widely used neurochemical cocktail (NMDA, dopamine, serotonin). No fictive locomotion could be elicited 1 day post-injury, but could within 3 days post-injury as readily as in age-matched uninjured control spinal cords. Burst patterning and coordination were largely similar in injured and control spinal cords but there were differences. Notably, in both groups there

  11. γ-Secretase modulators reduce endogenous amyloid β42 levels in human neural progenitor cells without altering neuronal differentiation

    OpenAIRE

    D’Avanzo, Carla; Sliwinski, Christopher; Wagner, Steven L.; Tanzi, Rudolph E.; Kim, Doo Yeon; Kovacs, Dora M.

    2015-01-01

    Soluble γ-secretase modulators (SGSMs) selectively decrease toxic amyloid β (Aβ) peptides (Aβ42). However, their effect on the physiologic functions of γ-secretase has not been tested in human model systems. γ-Secretase regulates fate determination of neural progenitor cells. Thus, we studied the impact of SGSMs on the neuronal differentiation of ReNcell VM (ReN) human neural progenitor cells (hNPCs). Quantitative PCR analysis showed that treatment of neurosphere-like ReN cell aggregate cultu...

  12. Osmotic Edema Rapidly Increases Neuronal Excitability Through Activation of NMDA Receptor-Dependent Slow Inward Currents in Juvenile and Adult Hippocampus

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    Kelli Lauderdale

    2015-09-01

    Full Text Available Cellular edema (cell swelling is a principal component of numerous brain disorders including ischemia, cortical spreading depression, hyponatremia, and epilepsy. Cellular edema increases seizure-like activity in vitro and in vivo, largely through nonsynaptic mechanisms attributable to reduction of the extracellular space. However, the types of excitability changes occurring in individual neurons during the acute phase of cell volume increase remain unclear. Using whole-cell patch clamp techniques, we report that one of the first effects of osmotic edema on excitability of CA1 pyramidal cells is the generation of slow inward currents (SICs, which initiate after approximately 1 min. Frequency of SICs increased as osmolarity decreased in a dose-dependent manner. Imaging of real-time volume changes in astrocytes revealed that neuronal SICs occurred while astrocytes were still in the process of swelling. SICs evoked by cell swelling were mainly nonsynaptic in origin and NMDA receptor-dependent. To better understand the relationship between SICs and changes in neuronal excitability, recordings were performed in increasingly physiological conditions. In the absence of any added pharmacological reagents or imposed voltage clamp, osmotic edema induced excitatory postsynaptic potentials and burst firing over the same timecourse as SICs. Like SICs, action potentials were blocked by NMDAR antagonists. Effects were more pronounced in adult (8–20 weeks old compared with juvenile (P15–P21 mice. Together, our results indicate that cell swelling triggered by reduced osmolarity rapidly increases neuronal excitability through activation of NMDA receptors. Our findings have important implications for understanding nonsynaptic mechanisms of epilepsy in relation to cell swelling and reduction of the extracellular space.

  13. A neuronal disruption in redox homeostasis elicited by ammonia alters the glycine/glutamate (GABA) cycle and contributes to MMA-induced excitability.

    Science.gov (United States)

    Royes, Luiz Fernando Freire; Gabbi, Patrícia; Ribeiro, Leandro Rodrigo; Della-Pace, Iuri Domingues; Rodrigues, Fernanda Silva; de Oliveira Ferreira, Ana Paula; da Silveira Junior, Mauro Eduardo Porto; da Silva, Luís Roberto Hart; Grisólia, Alan Barroso Araújo; Braga, Danielle Valente; Dobrachinski, Fernando; da Silva, Anderson Manoel Herculano Oliveira; Soares, Félix Alexandre Antunes; Marchesan, Sara; Furian, Ana Flavia; Oliveira, Mauro Schneider; Fighera, Michele Rechia

    2016-06-01

    Hyperammonemia is a common finding in children with methylmalonic acidemia. However, its contribution to methylmalonate-induced excitotoxicty is poorly understood. The aim of this study was to evaluate the mechanisms by which ammonia influences in the neurotoxicity induced by methylmalonate (MMA) in mice. The effects of ammonium chloride (NH4Cl 3, 6, and 12 mmol/kg; s.c.) on electroencephalographic (EEG) and behavioral convulsions induced by MMA (0.3, 0.66, and 1 µmol/2 µL, i.c.v.) were observed in mice. After, ammonia, TNF-α, IL1β, IL-6, nitrite/nitrate (NOx) levels, mitochondrial potential (ΔΨ), reactive oxygen species (ROS) generation, Methyl-Tetrazolium (MTT) reduction, succinate dehydrogenase (SDH), and Na(+), K(+)-ATPase activity levels were measured in the cerebral cortex. The binding of [(3)H]flunitrazepam, release of glutamate-GABA; glutamate decarboxylase (GAD) and glutamine synthetase (GS) activity and neuronal damage [opening of blood brain barrier (BBB) permeability and cellular death volume] were also measured. EEG recordings showed that an intermediate dose of NH4Cl (6 mmol/kg) increased the duration of convulsive episodes induced by MMA (0.66 μmol/2 μL i.c.v). NH4Cl (6 mmol/kg) administration also induced neuronal ammonia and NOx increase, as well as mitochondrial ROS generation throughout oxidation of 2,7-dichlorofluorescein diacetate (DCFH-DA) to DCF-RS, followed by GS and GAD inhibition. The NH4Cl plus MMA administration did not alter cytokine levels, plasma fluorescein extravasation, or neuronal damage. However, it potentiated DCF-RS levels, decreased the ΔΨ potential, reduced MTT, inhibited SDH activity, and increased Na(+), K(+)-ATPase activity. NH4Cl also altered the GABA cycle characterized by GS and GAD activity inhibition, [(3)H]flunitrazepam binding, and GABA release after MMA injection. On the basis of our findings, the changes in ROS and reactive nitrogen species (RNS) levels elicited by ammonia alter the glycine

  14. A molecular toolbox for rapid generation of viral vectors to up- or down-regulate in vivo neuronal gene expression

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    Melanie D. White

    2011-07-01

    Full Text Available We introduce a molecular toolbox for manipulation of neuronal gene expression in vivo. The toolbox includes promoters, ion channels, optogenetic tools, fluorescent proteins and intronic artificial microRNAs. The components are easily assembled into adeno-associated virus (AAV or lentivirus vectors using recombination cloning. We demonstrate assembly of toolbox components into lentivirus and AAV vectors and use these vectors for in vivo expression of inwardly rectifying potassium channels (Kir2.1, Kir3.1 and Kir3.2 and an artificial microRNA targeted against the ion channel HCN1 (HCN1 miR. We show that AAV assembled to express HCN1 miR produces efficacious and specific in vivo knockdown of HCN1 channels. Comparison of in vivo viral transduction using HCN1 miR with mice containing a germ line deletion of HCN1 reveals similar physiological phenotypes in cerebellar Purkinje cells. The easy assembly and re-usability of the toolbox components, together with the ability to up- or down-regulate neuronal gene expression in vivo, may be useful for applications in many areas of neuroscience.

  15. Apoptotic photoreceptor loss and altered expression of lysosomal proteins in the nclf mouse model of neuronal ceroid lipofuscinosis.

    Science.gov (United States)

    Bartsch, Udo; Galliciotti, Giovanna; Jofre, Guillermo F; Jankowiak, Wanda; Hagel, Christian; Braulke, Thomas

    2013-10-23

    Mutations in the CLN6 gene cause variant late-infantile neuronal ceroid lipofuscinosis, a lysosomal storage disorder clinically characterized by progressive loss of vision, dementia, seizures, and early death. Here, we analyzed the time course of photoreceptor loss and the role of lysosomes in nclf mice, an animal model of the human CLN6 disease. Labeling of apoptotic cells, activated astrocytes, and Müller cells, and expression analyses of glial fibrillary acidic protein, rhodopsin, and lysosomal proteins were performed on nclf mice during the course of retinal degeneration. In addition, the distribution and variability of storage material was examined at the ultrastructural level. Progressive apoptotic loss of photoreceptor cells was observed in nclf mice, resulting in reduction of the outer nuclear layer to approximately 3 rows of photoreceptor cells at 9 months of age. Onset of reactive gliosis was observed in 1-month-old nclf mice. Ultrastructural analysis revealed lysosomal storage material containing curvilinear and fingerprint-like inclusions in various retinal cell types. Expression levels of soluble mannose 6-phosphate-containing lysosomal enzymes, such as cathepsin D and the lysosomal membrane protein Lamp1, were increased in retinal cells of nclf mice. Accumulation of heterogeneous nondegraded macromolecules in dysfunctional lysosomes and autolysosomes impairs photoreceptor cells, ultimately leading to early-onset apoptotic death with subsequent activation of astrocytes and Müller cells in the retina of nclf mice. The defined steps of photoreceptor degeneration suggest that nclf mice might serve as an ideal animal model for experimental therapeutic approaches aimed at attenuating vision loss in neuronal ceroid lipofuscinosis.

  16. Knockdown of the glucocorticoid receptor alters functional integration of newborn neurons in the adult hippocampus and impairs fear-motivated behavior.

    Science.gov (United States)

    Fitzsimons, C P; van Hooijdonk, L W A; Schouten, M; Zalachoras, I; Brinks, V; Zheng, T; Schouten, T G; Saaltink, D J; Dijkmans, T; Steindler, D A; Verhaagen, J; Verbeek, F J; Lucassen, P J; de Kloet, E R; Meijer, O C; Karst, H; Joels, M; Oitzl, M S; Vreugdenhil, E

    2013-09-01

    Glucocorticoids (GCs) secreted after stress reduce adult hippocampal neurogenesis, a process that has been implicated in cognitive aspects of psychopathology, amongst others. Yet, the exact role of the GC receptor (GR), a key mediator of GC action, in regulating adult neurogenesis is largely unknown. Here, we show that GR knockdown, selectively in newborn cells of the hippocampal neurogenic niche, accelerates their neuronal differentiation and migration. Strikingly, GR knockdown induced ectopic positioning of a subset of the new granule cells, altered their dendritic complexity and increased their number of mature dendritic spines and mossy fiber boutons. Consistent with the increase in synaptic contacts, cells with GR knockdown exhibit increased basal excitability parallel to impaired contextual freezing during fear conditioning. Together, our data demonstrate a key role for the GR in newborn hippocampal cells in mediating their synaptic connectivity and structural as well as functional integration into mature hippocampal circuits involved in fear memory consolidation.

  17. Interleukin-18 alters protein expressions of neurodegenerative diseases-linked proteins in human SH-SY5Y neuron-like cells

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    Elina M Sutinen

    2014-08-01

    Full Text Available Chronic inflammation and oxidative stress (OS are present in Alzheimer´s disease (AD brains in addition to neuronal loss, Amyloid-β (Aβ plaques and hyperphosphorylated tau-protein neurofibrillary tangles. Previously we showed that levels of the pro-inflammatory cytokine, interleukin-18 (IL-18, are elevated in post-mortem AD brains. IL-18 can modulate the tau kinases, Cdk5 and GSK3β, as well as Aβ-production. IL-18 levels are also increased in AD risk diseases, including type-2 diabetes and obesity. Here, we explored other IL-18 regulated proteins in neuron-like SH-SY5Y cells. Differentiated SH-SY5Y cells, incubated with IL-18 for 24, 48 or 72h, were analyzed by two-dimensional gel electrophoresis (2D-DIGE. Specific altered protein spots were chosen and identified with mass spectrometry and verified by western immunoblotting. IL-18 had time-dependent effects on the SH-SY5Y proteome, modulating numerous protein levels/modifications. We concentrated on those related to OS (DDAH2, peroxiredoxins 2, 3 and 6, DJ-1, BLVRA, Aβ-degradation (MMP14, TIMP2, Aβ-aggregation (Septin-2 and modifications of axon growth and guidance associated, collapsing response mediator protein 2 (CRMP2. IL-18 significantly increased antioxidative enzymes, indicative of OS, and altered levels of glycolytic α- and γ-enolase and multifunctional 14-3-3γ and -ε, commonly affected in neurodegenerative diseases. MMP14, TIMP2, α-enolase and 14-3-3ε, indirectly involved in Aβ metabolism, as well as Septin-2 showed changes that increase Aβ levels. Increased 14-3-3γ may contribute to GSK3β driven tau hyperphosphorylation and CRMP2 Thr514 and Ser522 phosphorylation with the Thr555-site, a target for Rho kinase, showing time-dependent changes. IL-18 also increased caspase-1 levels and vacuolization of the cells. Although our SH-SY5Y cells were not aged, as neurons in AD, our work suggests that heightened or prolonged IL-18 levels can drive protein changes of known

  18. Novel rapid genotyping assays for neuronal ceroid lipofuscinosis in Border Collie dogs and high frequency of the mutant allele in Japan.

    Science.gov (United States)

    Mizukami, Keijiro; Chang, Hye-Sook; Yabuki, Akira; Kawamichi, Takuji; Kawahara, Natsuko; Hayashi, Daisuke; Hossain, Mohammad A; Rahman, Mohammad M; Uddin, Mohammad M; Yamato, Osamu

    2011-11-01

    Neuronal ceroid lipofuscinosis (NCL) constitutes a group of recessively inherited lysosomal storage diseases that primarily affect neuronal cells. Such diseases share certain clinical and pathologic features in human beings and animals. Neuronal ceroid lipofuscinosis in Border Collie dogs was first detected in Australia in the 1980s, and the pathogenic mutation was shown to be a nonsense mutation (c.619C>T) in exon 4 in canine CLN5 gene. In the present study, novel rapid genotyping assays including polymerase chain reaction (PCR)-restriction fragment length polymorphism, PCR primer-induced restriction analysis, mutagenically separated PCR, and real-time PCR with TaqMan minor groove binder probes, were developed. The utility of microchip electrophoresis was also evaluated. Furthermore, a genotyping survey was carried out in a population of Border Collies in Japan using these assays to determine the current allele frequency in Japan, providing information to control and prevent this disease in the next stage. All assays developed in the current study are available to discriminate these genotypes, and microchip electrophoresis showed a timesaving advantage over agarose gel electrophoresis. Of all assays, real-time PCR was the most suitable for large-scale examination because of its high throughput. The genotyping survey demonstrated that the carrier frequency was 8.1%. This finding suggested that the mutant allele frequency of NCL in Border Collies is high enough in Japan that measures to control and prevent the disease would be warranted. The genotyping assays developed in the present study could contribute to the prevention of NCL in Border Collies.

  19. Blocking systemic nitric oxide production alters neuronal activation in brain structures involved in cardiovascular regulation during polymicrobial sepsis.

    Science.gov (United States)

    Bruhn, Fernando Henrique Pascoti; Corrêa, Pollyanna Barbosa Farias; Oliveira-Pelegrin, Gabriela Ravanelli; Rocha, Maria José Alves

    2009-04-10

    In a previous study, we concluded that overproduction of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) in the late phase of sepsis prevents hypothalamic activation, blunts vasopressin secretion and contributes to hypotension, irreversible shock and death. The aim of this follow-up study was to evaluate if the same neuronal activation pattern happens in brain structures related to cardiovascular functions. Male Wistar rats received intraperitoneal injections of aminoguanidine, an iNOS inhibitor, or saline 30 min before cecal ligation and puncture (CLP) or sham surgeries. The animals were perfused 6 or 24h after the surgeries and the brains were removed and processed for Fos immunocytochemistry. We observed an increase (Pafter CLP in the area postrema (AP), nucleus of the tractus solitarius (NTS), ventral lateral medulla (VLM), locus coeruleus (LC) and parabrachial nucleus (PB). At 24h after CLP, however, c-fos expression was strongly decreased in all these nuclei (Pafter CLP, but showed an opposite effect at 24h, with an increase in the AP, NTS, and also in the VLM. No such effect was observed in the LC and PB at 6 or 24h. In all control animals, c-fos expression was minimal or absent. We conclude that in the early phase of sepsis iNOS-derived NO may be partially responsible for the activation of brain structures related to cardiovascular regulation. During the late phase, however, this activation is reduced or abolished.

  20. Altered Neuronal Dynamics in the Striatum on the Behavior of Huntingtin Interacting Protein 14 (HIP14 Knockout Mice

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    Ana María Estrada-Sánchez

    2013-11-01

    Full Text Available Huntington’s disease (HD, a neurodegenerative disorder caused by an expanded CAG repeat in the huntingtin gene, impairs information processing in the striatum, which, as part of the basal ganglia, modulates motor output. Growing evidence suggests that huntingtin interacting protein 14 (HIP14 contributes to HD neuropathology. Here, we recorded local field potentials (LFPs in the striatum as HIP14 knockout mice and wild-type controls freely navigated a plus-shaped maze. Upon entering the choice point of the maze, HIP14 knockouts tend to continue in a straight line, turning left or right significantly less often than wild-types, a sign of motor inflexibility that also occurs in HD mice. Striatal LFP activity anticipates this difference. In wild-types, the power spectral density pattern associated with entry into the choice point differs significantly from the pattern immediately before entry, especially at low frequencies (≤13 Hz, whereas HIP14 knockouts show no change in LFP activity as they enter the choice point. The lack of change in striatal activity may explain the turning deficit in the plus maze. Our results suggest that HIP14 plays a critical role in the aberrant behavioral modulation of striatal neuronal activity underlying motor inflexibility, including the motor signs of HD.

  1. Rapid changes in phospho-MAP/tau epitopes during neuronal stress: cofilin-actin rods primarily recruit microtubule binding domain epitopes.

    Directory of Open Access Journals (Sweden)

    Ineka T Whiteman

    Full Text Available Abnormal mitochondrial function is a widely reported contributor to neurodegenerative disease including Alzheimer's disease (AD, however, a mechanistic link between mitochondrial dysfunction and the initiation of neuropathology remains elusive. In AD, one of the earliest hallmark pathologies is neuropil threads comprising accumulated hyperphosphorylated microtubule-associated protein (MAP tau in neurites. Rod-like aggregates of actin and its associated protein cofilin (AC rods also occur in AD. Using a series of antibodies--AT270, AT8, AT100, S214, AT180, 12E8, S396, S404 and S422--raised against different phosphoepitopes on tau, we characterize the pattern of expression and re-distribution in neurites of these phosphoepitope labels during mitochondrial inhibition. Employing chick primary neuron cultures, we demonstrate that epitopes recognized by the monoclonal antibody 12E8, are the only species rapidly recruited into AC rods. These results were recapitulated with the actin depolymerizing drug Latrunculin B, which induces AC rods and a concomitant increase in the 12E8 signal measured on Western blot. This suggests that AC rods may be one way in which MAP redistribution and phosphorylation is influenced in neurons during mitochondrial stress and potentially in the early pathogenesis of AD.

  2. Neuronal and glial alterations in the cerebellar cortex of maternally deprived rats: gender differences and modulatory effects of two inhibitors of endocannabinoid inactivation.

    Science.gov (United States)

    López-Gallardo, M; Llorente, R; Llorente-Berzal, A; Marco, E M; Prada, C; Di Marzo, V; Viveros, M P

    2008-10-01

    Adult animals submitted to a single prolonged episode of maternal deprivation (MD) [24 h, postnatal day 9-10] show behavioral alterations that resemble specific symptoms of schizophrenia. Accordingly, this experimental procedure has been proposed as an animal model of schizophrenia based on the neurodevelopmental hypothesis. We have recently reported that MD-induced sex-dependent alterations in the hippocampus of neonatal rats. In view of recent evidence for important implications of the cerebellum in neurodevelopmental psychiatric diseases, we have now addressed possible degenerative changes in the cerebellar cortex of neonatal Wistar rats of both genders. To evaluate the presence of degenerated nerve cells, we used Fluoro-Jade C staining and for the study of astrocytes, we employed glial fibrillary acidic protein. Further, we analyzed the modulatory actions of two inhibitors of endocannabinoids inactivation, the fatty acid amide hydrolase inhibitor N-arachidonoyl-serotonin, AA-5-HT, and the endocannabinoid reuptake inhibitor, OMDM-2 (daily subcutaneous injections during the postnatal period 7-12). The animals were sacrificed at postnatal Day 13. MD induced significant increases in the number of Fluoro-Jade C positive cells (indicative of degenerating neurons) and in the number of glial fibrillary acidic protein positive cells, only in males. The two cannabinoid compounds reversed or attenuated these effects. The present results provide new insights regarding the psychopathological implications of the cerebellum, the role of the endocannabinoid system in neural development, and the possible neurodevelopmental basis of gender differences in schizophrenia. (c) 2008 Wiley Periodicals, Inc.

  3. Altered balance of glutamatergic/GABAergic synaptic input and associated changes in dendrite morphology after BDNF expression in BDNF-deficient hippocampal neurons

    OpenAIRE

    Singh, B.; Henneberger, C.; Betances, D.; Arevalo, M.A.; Rodriguez-Tebar, A.; Meier, J.C.; Grantyn, R.

    2006-01-01

    Cultured neurons from bdnf-/- mice display reduced densities of synaptic terminals, although in vivo these deficits are small or absent. Here we aimed at clarifying the local responses to postsynaptic brain-derived neurotrophic factor (BDNF). To this end, solitary enhanced green fluorescent protein (EGFP)-labeled hippocampal neurons from bdnf-/- mice were compared with bdnf-/- neurons after transfection with BDNF, bdnf-/- neurons after transient exposure to exogenous BDNF, and bdnf+/+ neurons...

  4. Perfluorooctane sulfonate induces neuronal and oligodendrocytic differentiation in neural stem cells and alters the expression of PPARγ in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Wan Ibrahim, Wan Norhamidah, E-mail: hamidah@science.upm.edu.my [Department of Neuroscience, Karolinska Institutet, S-17177 Stockholm (Sweden); Tofighi, Roshan, E-mail: Roshan.Tofighi@ki.se [Department of Neuroscience, Karolinska Institutet, S-17177 Stockholm (Sweden); Onishchenko, Natalia, E-mail: Natalia.Onishchenko@ki.se [Department of Neuroscience, Karolinska Institutet, S-17177 Stockholm (Sweden); Rebellato, Paola, E-mail: Paola.Rebellato@ki.se [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm (Sweden); Bose, Raj, E-mail: Raj.Bose@ki.se [Department of Neuroscience, Karolinska Institutet, S-17177 Stockholm (Sweden); Uhlén, Per, E-mail: Per.Uhlen@ki.se [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm (Sweden); Ceccatelli, Sandra, E-mail: Sandra.Ceccatelli@ki.se [Department of Neuroscience, Karolinska Institutet, S-17177 Stockholm (Sweden)

    2013-05-15

    Perfluorinated compounds are ubiquitous chemicals of major concern for their potential adverse effects on the human population. We have used primary rat embryonic neural stem cells (NSCs) to study the effects of perfluorooctane sulfonate (PFOS) on the process of NSC spontaneous differentiation. Upon removal of basic fibroblast growth factor, NSCs were exposed to nanomolar concentrations of PFOS for 48 h, and then allowed to differentiate for additional 5 days. Exposure to 25 or 50 nM concentration resulted in a lower number of proliferating cells and a higher number of neurite-bearing TuJ1-positive cells, indicating an increase in neuronal differentiation. Exposure to 50 nM also significantly increased the number of CNPase-positive cells, pointing to facilitation of oligodendrocytic differentiation. PPAR genes have been shown to be involved in PFOS toxicity. By q-PCR we detected an upregulation of PPARγ with no changes in PPARα or PPARδ genes. One of the downstream targets of PPARs, the mitochondrial uncoupling protein 2 (UCP2) was also upregulated. The number of TuJ1- and CNPase-positive cells increased after exposure to PPARγ agonist rosiglitazone (RGZ, 3 μM) and decreased after pre-incubation with the PPARγ antagonist GW9662 (5 μM). RGZ also upregulated the expression of PPARγ and UCP2 genes. Meanwhile GW9662 abolished the UCP2 upregulation and decreased Ca{sup 2+} activity induced by PFOS. Interestingly, a significantly higher expression of PPARγ and UCP3 genes was also detected in mouse neonatal brain after prenatal exposure to PFOS. These data suggest that PPARγ plays a role in the alteration of spontaneous differentiation of NSCs induced by nanomolar concentrations of PFOS. - Highlights: • PFOS decreases proliferation of neural stem cells (NSCs). • PFOS induces neuronal and oligodendrocytic differentiation in NSCs. • PFOS alters expression of PPARγ and UCP2 in vitro. • PFOS alters expression of PPARγ and UCP3 in vivo. • Block of PPAR

  5. Rapid changes in the sensitivity of arcuate nucleus neurons to central ghrelin in relation to feeding status.

    Science.gov (United States)

    Scott, Victoria; McDade, Donna M; Luckman, Simon M

    2007-01-30

    Ghrelin, the endogenous ligand for the growth hormone secretagogue (GHS) receptor, stimulates feeding and increases body weight. Systemic ghrelin administration induces the immediate-early gene protein product, c-Fos, in the arcuate nucleus of the hypothalamus (ARC) of satiated rats and this increase is potentiated in fasted rats. The aim of this study was to determine whether potentiation was seen in fasted animals after intracerebroventricular (i.c.v) administration of ghrelin and to identify the hypothalamic nuclei activated by this peptide. In addition we investigated if allowing fasted animals to re-feed for 1 h prior to i.c.v. ghrelin injection affected the c-Fos response. Using c-Fos immunocytochemistry, we demonstrated that i.c.v. ghrelin activated several hypothalamic nuclei, including the ARC, paraventricular nucleus (PVH) and the lateral hypothalamus (LH). The c-Fos response was greater in fasted animals compared with satiated animals. Fasted rats allowed access to food for 1 h prior to central ghrelin administration showed an attenuated response in the ARC, similar to the response seen in fed animals. However, the response in the LH (including in the orexin neurons) was further potentiated. The latter may reflect a connection between the hypothalamus and regions of the brain responding to the reward value of the meal.

  6. Altered spontaneous neuronal activity in chronic posttraumatic stress disorder patients before and after a 12-week paroxetine treatment.

    Science.gov (United States)

    Zhu, Hongru; Qiu, Changjian; Meng, Yajing; Cui, Haofei; Zhang, Yan; Huang, Xiaoqi; Zhang, Junran; Li, Tao; Gong, Qiyong; Zhang, Wei; Lui, Su

    2015-03-15

    Abnormal functional brain activity has been revealed in patients with Posttraumatic Stress Disorder (PTSD) in recent years, while the recovery neuromechanism of PTSD has not yet been elucidated. The aim of this study was to investigate the altered spontaneous brain activity in treatment-naïve chronic PTSD patients before and after 12 weeks׳ treatment with paroxetine. Twenty-one earthquake-related PTSD patients and seventeen traumatized controls underwent a resting functional magnetic resonance imaging (Rs-fMRI) scan at baseline. Amplitude of low-frequency fluctuation (ALFF) was calculated and compared between PTSD patients and controls. Then, the PTSD group completed 12 weeks of treatment with paroxetine, and Rs-fMRI was repeated to compare with the baseline. Lastly, correlation analyses of ALFF values within altered brain areas were conducted. Hyperactive function of visual cortex was observed in PTSD patients before and after treatment. After treatment, significantly increased ALFF values were observed in the left orbitofrontal cortex (OFC), while decreased ALFF values were found in the precuneus. Interestingly, a negative correlation between the mean ALFF values of OFC and those of precuneus and visual cortex was only observed in controls, but not in PTSD patients pre- or post-treatment. A corresponding control condition was absent in this study. The findings showed that manipulating regional spontaneous activity of precuneus and OFC could be a potential prognostic indicator of PTSD. However, hyperactive function of visual cortex and disrupted connections between OFC, precuneus and visual cortex did not reverse after treatment, which could be a potential target for further treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Deep brain stimulation of the subthalamic nucleus preferentially alters the translational profile of striatopallidal neurons in an animal model of Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Iman eKamali Sarvestani

    2015-06-01

    Full Text Available Deep brain stimulation targeting the subthalamic nucleus (STN-DBS is an effective surgical treatment for the motor symptoms of Parkinson’s disease (PD, the precise neuronal mechanisms of which both at molecular and network levels remain a topic of debate. Here we employ two transgenic mouse lines, combining translating ribosomal affinity purification (TRAP with bacterial artificial chromosome expression (Bac, to selectively identify changes in translational gene expression in either Drd1a-expressing striatonigral or Drd2-expressing striatopallidal medium spiny neurons (MSNs of the striatum following STN-DBS. 6-hydroxydopamine lesioned mice received either 5 days stimulation via a DBS electrode implanted in the ipsilateral STN or 5 days sham treatment (no stimulation. Striatal polyribosomal RNA was selectively purified from either Drd2 or Drd1a MSNs using the TRAP method and gene expression profiling performed. We identified 8 significantly altered genes in Drd2 MSNs (Vps33b, Ppp1r3c, Mapk4, Sorcs2, Neto1, Abca1, Penk1 and Gapdh and 2 overlapping genes in Drd1a MSNs (Penk1 and Ppp1r3c implicated in the molecular mechanisms of STN-DBS. A detailed functional analysis, using a further 728 probes implicated in STN-DBS, suggested an increased ability to receive excitation (mediated by increased dendritic spines, increased calcium influx and enhanced excitatory post synaptic potentials accompanied by processes that would hamper the initiation of action potentials, transport of neurotransmitters from soma to axon terminals and vesicular release in Drd2-expressing MSNs. Finally, changes in expression of several genes involved in apoptosis as well as cholesterol and fatty acid metabolism were also identified. This increased understanding of the molecular mechanisms induced by STN-DBS may reveal novel targets for future non-surgical therapies for PD.

  8. Estrogen activates rapid signaling in the brain: role of estrogen receptor alpha and estrogen receptor beta in neurons and glia.

    Science.gov (United States)

    Mhyre, A J; Dorsa, D M

    2006-01-01

    The aging process is known to coincide with a decline in circulating sex hormone levels in both men and women. Due to an increase in the average lifespan, a growing number of post-menopausal women are now receiving hormone therapy for extended periods of time. Recent findings of the Women's Health Initiative, however, have called into question the benefits of long-term hormone therapy for treating symptoms of menopause. The results of this study are still being evaluated, but it is clear that a better understanding of the molecular effects of estradiol is needed in order to develop new estrogenic compounds that activate specific mechanisms but lack adverse side effects. Traditionally, the effects of estradiol treatment have been ascribed to changes in gene expression, namely transcription at estrogen response elements. This review focuses on emerging information that estradiol can also activate a repertoire of membrane-initiated signaling pathways and that these rapid signaling events lead to functional changes at the cellular level. The various types of cells in the brain can respond differently to estradiol treatment based on the signaling properties of the cell, as well as which receptor, estrogen receptor alpha and/or estrogen receptor beta, is expressed. Taken together, these findings suggest that the estradiol-induced activation of membrane-initiated signaling pathways occurs in a cell-type specific manner and can differentially influence how the cells respond to various insults.

  9. Rapid transient isoform-specific neuregulin1 transcription in motor neurons is regulated by neurotrophic factors and axon-target interactions

    Science.gov (United States)

    Wang, Jiajing; Hmadcha, Abdelkrim; Zakarian, Vaagn; Song, Fei; Loeb, Jeffrey A.

    2015-01-01

    The neuregulins (NRGs) are a family of alternatively spliced factors that play important roles in nervous system development and disease. In motor neurons, NRG1 expression is regulated by activity and neurotrophic factors, however, little is known about what controls isoform-specific transcription. Here we show that NRG1 expression in the chick embryo increases in motor neurons that have extended their axons and that limb bud ablation before motor axon outgrowth prevents this induction, suggesting a trophic role from the developing limb. Consistently, NRG1 induction after limb bud ablation can be rescued by adding back the neurotrophic factors BDNF and GDNF. Mechanistically, BDNF induces a rapid and transient increase in type I and type III NRG1 mRNAs that peak at 4 h in rat embryonic ventral spinal cord cultures. Blocking MAPK or PI3K signaling or blocking transcription with Actinomycin D blocks BDNF induced NRG1 gene induction. BDNF had no effect on mRNA degradation, suggesting that transcriptional activation rather than message stability is important. Furthermore, BDNF activates a reporter construct that includes 700bp upstream of the type I NRG1 start site. Protein synthesis is also required for type I NRG1 mRNA transcription as cycloheximide produced a super-induction of type I, but not type III NRG1 mRNA, possibly through a mechanism involving sustained activation of MAPK and PI3K. These results reveal the existence of highly responsive, transient transcriptional regulatory mechanisms that differentially modulate NRG1 isoform expression as a function of extracellular and intracellular signaling cascades and mediated by neurotrophic factors and axon-target interactions. PMID:25913151

  10. SN56 basal forebrain cholinergic neuronal loss after acute and long-term chlorpyrifos exposure through oxidative stress generation; P75(NTR) and α7-nAChRs alterations mediated partially by AChE variants disruption.

    Science.gov (United States)

    Del Pino, Javier; Moyano, Paula; Anadon, María José; García, José Manuel; Díaz, María Jesús; Gómez, Gloria; García, Jimena; Frejo, María Teresa

    2016-04-15

    Chlorpyrifos (CPF) is an organophosphates insecticide reported to induce, both after acute and repeated exposure, cognitive disorders and basal forebrain cholinergic neuronal loss, involved on learning and memory regulation, which could be the cause of such cognitive disorders. This neuronal loss was mediated partially by AChE variants alteration, suggesting other mechanisms are involved. In this regard, CPF induces oxidative stress that is implicated in the induction of cognitive deficits, changes in AChE variants expression and neuronal loss. Otherwise, it has been shown that P75(NTR) and the α7-nAChRs expression is altered in basal forebrain of rats after CPF long-term exposure; this alteration has been related with oxidative stress induction, cholinergic cell loss, and disruption of learning and memory processes. According to these data, we hypothesized that CPF induces basal forebrain cholinergic neuronal loss through induction of oxidative stress produced by P75(NTR) and α7-nAChRs altered expression, which could mediate this action in part through AChE variants disruption. We evaluated this hypothesis in septal SN56 basal forebrain cholinergic neurons, after 24h and 14days CPF exposure in vitro. This study shows that CPF upregulated P75(NTR) and downregulated α7-nAChRs expression, which increased H2O2 and malondialdehyde content and reduced cell viability partially through AChE variants induction. Alpha7-nAChRs repression induced oxidative stress and cell death partially through this mechanism, but P75(NTR) overexpression did not produce these effects, although it increased oxidative stress and cell death after CPF treatment, showing that its overexpression increases cell vulnerability. Our present results provide new understanding of the mechanisms contributing to the harmful effects of CPF. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. SynPAnal: software for rapid quantification of the density and intensity of protein puncta from fluorescence microscopy images of neurons.

    Directory of Open Access Journals (Sweden)

    Eric Danielson

    Full Text Available Continuous modification of the protein composition at synapses is a driving force for the plastic changes of synaptic strength, and provides the fundamental molecular mechanism of synaptic plasticity and information storage in the brain. Studying synaptic protein turnover is not only important for understanding learning and memory, but also has direct implication for understanding pathological conditions like aging, neurodegenerative diseases, and psychiatric disorders. Proteins involved in synaptic transmission and synaptic plasticity are typically concentrated at synapses of neurons and thus appear as puncta (clusters in immunofluorescence microscopy images. Quantitative measurement of the changes in puncta density, intensity, and sizes of specific proteins provide valuable information on their function in synaptic transmission, circuit development, synaptic plasticity, and synaptopathy. Unfortunately, puncta quantification is very labor intensive and time consuming. In this article, we describe a software tool designed for the rapid semi-automatic detection and quantification of synaptic protein puncta from 2D immunofluorescence images generated by confocal laser scanning microscopy. The software, dubbed as SynPAnal (for Synaptic Puncta Analysis, streamlines data quantification for puncta density and average intensity, thereby increases data analysis throughput compared to a manual method. SynPAnal is stand-alone software written using the JAVA programming language, and thus is portable and platform-free.

  12. High glucose induced alteration of SIRTs in endothelial cells causes rapid aging in a p300 and FOXO regulated pathway.

    Directory of Open Access Journals (Sweden)

    Rokhsana Mortuza

    Full Text Available In diabetes, some of the cellular changes are similar to aging. We hypothesized that hyperglycemia accelerates aging-like changes in the endothelial cells (ECs and tissues leading to structural and functional damage. We investigated glucose-induced aging in 3 types of ECs using senescence associated β-gal (SA β-gal staining and cell morphology. Alterations of sirtuins (SIRTs and their downstream mediator FOXO and oxidative stress were investigated. Relationship of such alteration with histone acetylase (HAT p300 was examined. Similar examinations were performed in tissues of diabetic animals. ECs in high glucose (HG showed evidence of early senescence as demonstrated by increased SA β-gal positivity and reduced replicative capacities. These alterations were pronounced in microvascular ECs. They developed an irregular and hypertrophic phenotype. Such changes were associated with decreased SIRT (1-7 mRNA expressions. We also found that p300 and SIRT1 regulate each other in such process, as silencing one led to increase of the others' expression. Furthermore, HG caused reduction in FOXO1's DNA binding ability and antioxidant target gene expressions. Chemically induced increased SIRT1 activity and p300 knockdown corrected these abnormalities slowing aging-like changes. Diabetic animals showed increased cellular senescence in renal glomerulus and retinal blood vessels along with reduced SIRT1 mRNA expressions in these tissues. Data from this study demonstrated that hyperglycemia accelerates aging-like process in the vascular ECs and such process is mediated via downregulation of SIRT1, causing reduction of mitochondrial antioxidant enzyme in a p300 and FOXO1 mediated pathway.

  13. LRP1 controls biosynthetic and endocytic trafficking of neuronal prion protein

    DEFF Research Database (Denmark)

    Parkyn, Celia J; Vermeulen, Esmeralda G M; Mootoosamy, Roy C

    2008-01-01

    The trafficking of normal cellular prion protein (PrP(C)) is believed to control its conversion to the altered conformation (designated PrP(Sc)) associated with prion disease. Although anchored to the membrane by means of glycosylphosphatidylinositol (GPI), PrP(C) on neurons is rapidly and consti......The trafficking of normal cellular prion protein (PrP(C)) is believed to control its conversion to the altered conformation (designated PrP(Sc)) associated with prion disease. Although anchored to the membrane by means of glycosylphosphatidylinositol (GPI), PrP(C) on neurons is rapidly...

  14. Altered trunk muscle coordination during rapid trunk flexion in people in remission of recurrent low back pain.

    Science.gov (United States)

    D'hooge, Roseline; Hodges, Paul; Tsao, Henry; Hall, Leanne; Macdonald, David; Danneels, Lieven

    2013-02-01

    People with a history of low back pain (LBP) are at high risk to encounter additional LBP episodes. During LBP remission, altered trunk muscle control has been suggested to negatively impact spinal health. As sudden LBP onset is commonly reported during trunk flexion, the aim of the current study is to investigate whether dynamic trunk muscle recruitment is altered in LBP remission. Eleven people in remission of recurrent LBP and 14 pain free controls performed cued trunk flexion during a loaded and unloaded condition. Electromyographic activity was recorded from paraspinal (lumbar and thoracic erector spinae, latissimus dorsi, deep and superficial multifidus) and abdominal muscles (obliquus internus, externus and rectus abdominis) with surface and fine-wire electrodes. LBP participants exhibited higher levels of co-contraction of flexor/extensor muscles, lower agonistic abdominal and higher antagonistic paraspinal muscle activity than controls, both when data were analyzed in grouped and individual muscle behavior. A sub-analysis in people with unilateral LBP (n = 6) pointed to opposing changes in deep and superficial multifidus in relation to the pain side. These results suggest that dynamic trunk muscle control is modified during LBP remission, and might possibly increase spinal load and result in earlier muscle fatigue due to intensified muscle usage. These negative consequences for spinal health could possibly contribute to recurrence of LBP. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Glycogen synthase kinase 3 beta alters anxiety-, depression-, and addiction-related behaviors and neuronal activity in the nucleus accumbens shell.

    Science.gov (United States)

    Crofton, Elizabeth J; Nenov, Miroslav N; Zhang, Yafang; Scala, Federico; Page, Sean A; McCue, David L; Li, Dingge; Hommel, Jonathan D; Laezza, Fernanda; Green, Thomas A

    2017-05-01

    Psychiatric disorders such as anxiety, depression and addiction are often comorbid brain pathologies thought to share common mechanistic biology. As part of the cortico-limbic circuit, the nucleus accumbens shell (NAcSh) plays a fundamental role in integrating information in the circuit, such that modulation of NAcSh circuitry alters anxiety, depression, and addiction-related behaviors. Intracellular kinase cascades in the NAcSh have proven important mediators of behavior. To investigate glycogen-synthase kinase 3 (GSK3) beta signaling in the NAcSh in vivo we knocked down GSK3beta expression with a novel adeno-associated viral vector (AAV2) and assessed changes in anxiety- and depression-like behavior and cocaine self-administration in GSK3beta knockdown rats. GSK3beta knockdown reduced anxiety-like behavior while increasing depression-like behavior and cocaine self-administration. Correlative electrophysiological recordings in acute brain slices were used to assess the effect of AAV-shGSK3beta on spontaneous firing and intrinsic excitability of tonically active interneurons (TANs), cells required for input and output signal integration in the NAcSh and for processing reward-related behaviors. Loose-patch recordings showed that TANs transduced by AAV-shGSK3beta exhibited reduction in tonic firing and increased spike half width. When assessed by whole-cell patch clamp recordings these changes were mirrored by reduction in action potential firing and accompanied by decreased hyperpolarization-induced depolarizing sag potentials, increased action potential current threshold, and decreased maximum rise time. These results suggest that silencing of GSK3beta in the NAcSh increases depression- and addiction-related behavior, possibly by decreasing intrinsic excitability of TANs. However, this study does not rule out contributions from other neuronal sub-types. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Gestational Exposure to Air Pollution Alters Cortical Volume, Microglial Morphology, and Microglia-Neuron Interactions in a Sex-Specific Manner

    Directory of Open Access Journals (Sweden)

    Jessica L. Bolton

    2017-05-01

    Full Text Available Microglia are the resident immune cells of the brain, important for normal neural development in addition to host defense in response to inflammatory stimuli. Air pollution is one of the most pervasive and harmful environmental toxicants in the modern world, and several large scale epidemiological studies have recently linked prenatal air pollution exposure with an increased risk of neurodevelopmental disorders such as autism spectrum disorder (ASD. Diesel exhaust particles (DEP are a primary toxic component of air pollution, and markedly activate microglia in vitro and in vivo in adult rodents. We have demonstrated that prenatal exposure to DEP in mice, i.e., to the pregnant dams throughout gestation, results in a persistent vulnerability to behavioral deficits in adult offspring, especially in males, which is intriguing given the greater incidence of ASD in males to females (∼4:1. Moreover, there is a striking upregulation of toll-like receptor (TLR 4 gene expression within the brains of the same mice, and this expression is primarily in microglia. Here we explored the impact of gestational exposure to DEP or vehicle on microglial morphology in the developing brains of male and female mice. DEP exposure increased inflammatory cytokine protein and altered the morphology of microglia, consistent with activation or a delay in maturation, only within the embryonic brains of male mice; and these effects were dependent on TLR4. DEP exposure also increased cortical volume at embryonic day (E18, which switched to decreased volume by post-natal day (P30 in males, suggesting an impact on the developing neural stem cell niche. Consistent with this hypothesis, we found increased microglial-neuronal interactions in male offspring that received DEP compared to all other groups. Taken together, these data suggest a mechanism by which prenatal exposure to environmental toxins may affect microglial development and long-term function, and thereby contribute

  17. C9orf72 Hexanucleotide Expansions Are Associated with Altered Endoplasmic Reticulum Calcium Homeostasis and Stress Granule Formation in Induced Pluripotent Stem Cell‐Derived Neurons from Patients with Amyotrophic Lateral Sclerosis and Frontotemporal Dementia

    Science.gov (United States)

    Dafinca, Ruxandra; Scaber, Jakub; Ababneh, Nida'a; Lalic, Tatjana; Weir, Gregory; Christian, Helen; Vowles, Jane; Douglas, Andrew G.L.; Fletcher‐Jones, Alexandra; Browne, Cathy; Nakanishi, Mahito; Turner, Martin R.; Wade‐Martins, Richard

    2016-01-01

    Abstract An expanded hexanucleotide repeat in a noncoding region of the C9orf72 gene is a major cause of amyotrophic lateral sclerosis (ALS), accounting for up to 40% of familial cases and 7% of sporadic ALS in European populations. We have generated induced pluripotent stem cells (iPSCs) from fibroblasts of patients carrying C9orf72 hexanucleotide expansions, differentiated these to functional motor and cortical neurons, and performed an extensive phenotypic characterization. In C9orf72 iPSC‐derived motor neurons, decreased cell survival is correlated with dysfunction in Ca2+ homeostasis, reduced levels of the antiapoptotic protein Bcl‐2, increased endoplasmic reticulum (ER) stress, and reduced mitochondrial membrane potential. Furthermore, C9orf72 motor neurons, and also cortical neurons, show evidence of abnormal protein aggregation and stress granule formation. This study is an extensive characterization of iPSC‐derived motor neurons as cellular models of ALS carrying C9orf72 hexanucleotide repeats, which describes a novel pathogenic link between C9orf72 mutations, dysregulation of calcium signaling, and altered proteostasis and provides a potential pharmacological target for the treatment of ALS and the related neurodegenerative disease frontotemporal dementia. Stem Cells 2016;34:2063–2078 PMID:27097283

  18. Medial prefrontal cortical estradiol rapidly alters memory system bias in female rats: ultrastructural analysis reveals membrane-associated estrogen receptors as potential mediators.

    Science.gov (United States)

    Almey, Anne; Cannell, Elizabeth; Bertram, Kyla; Filardo, Edward; Milner, Teresa A; Brake, Wayne G

    2014-11-01

    High plasma levels of estradiol (E2) are associated with use of a place memory system over a response memory system. We examined whether infusing estradiol into the medial prefrontal cortex (mPFC) or anterior cingulate cortex (AC) could affect memory system bias in female rats. We also examined the ultrastructural distribution of estrogen receptor (ER)-α, ERβ, and G protein-coupled estrogen receptor 1 (GPER1) in the mPFC of female rats as a mechanism for the behavioral effects of E2 in the mPFC. Each rat was infused bilaterally with either E2 (0.13 μg) or vehicle into the mPFC or AC. The majority of E2 mPFC rats used place memory. In contrast, the majority of mPFC vehicle rats and AC E2 or vehicle rats used response memory. These data show that mPFC E2 rapidly biases females to use place memory. Electron microscopic analysis demonstrated that ERα, ERβ, and GPER1 are localized in the mPFC, almost exclusively at extranuclear sites. This is the first time that GPER1 has been localized to the mPFC of rats and the first time that ERα and ERβ have been described at extranuclear sites in the rat mPFC. The majority of receptors were observed on axons and axon terminals, suggesting that estrogens alter presynaptic transmission in the mPFC. This provides a mechanism via which ERs could rapidly alter transmission in the mPFC to alter PFC-dependent behaviors, such as memory system bias. The discrete nature of immunolabeling for these membrane-associated ERs may explain the discrepancy in previous light microscopy studies.

  19. Rapid reduction of MDCK cell cholesterol by methyl-beta-cyclodextrin alters steady state transepithelial electrical resistance.

    Science.gov (United States)

    Francis, S A; Kelly, J M; McCormack, J; Rogers, R A; Lai, J; Schneeberger, E E; Lynch, R D

    1999-07-01

    The role of plasma membrane lipids in regulating the passage of ions and other solutes through the paracellular pathway remains controversial. In this study we explore the contribution of cholesterol (CH) in maintaining the barrier function of an epithelial cell line using the CH-solubilizing agent methyl beta-cyclodextrin (MBCD) to stimulate CH efflux. Inclusion of 20 mM MBCD in both apical and basolateral media reduced CH levels by 70-80% with no significant effect on cell viability. Most of that decrease occurred during the first 30 min of incubation. Recovery of CH content to initial values was nearly complete 22 h after removal of MBCD. Within 30 min of adding MBCD to the culture medium, transepithelial electrical resistance (TER) increased, reaching maximum values 30-40% above controls. This early rise in TER occurred when MBCD was added to either side of the monolayer. The later rapid decline in TER was observed only when MBCD bathed the basolateral surface from which, coincidentally, CH efflux was most rapid. Freeze fracture replicas and transmission electron microscopy of monolayers exposed to MBCD for only 30 min revealed no increase in either the average tight junction (TJ) strand number or the dimensions of the lateral intercellular space. There was a statistically significant increase in the number of TJ particles associated with the E fracture face at this time. This raises the interesting possibility that during CH efflux there is a change in the interaction between TJ particles and underlying cytoskeletal elements. There was no change in staining for occludin and ZO-1. After exposing the basolateral surface to MBCD for 2 h, TER fell below control levels. The accompanying increase in mannitol flux suggests strongly that the decrease in TER resulted from an increase in the permeability of the paracellular and not the transcellular pathway. A decrease in immuno-staining for occludin and ZO-1 at TJs, a striking accumulation of actin at tri

  20. Rapid modulation of ultraviolet shielding in plants is influenced by solar ultraviolet radiation and linked to alterations in flavonoids.

    Science.gov (United States)

    Barnes, Paul W; Tobler, Mark A; Keefover-Ring, Ken; Flint, Stephan D; Barkley, Anne E; Ryel, Ronald J; Lindroth, Richard L

    2016-01-01

    The accumulation of ultraviolet (UV)-absorbing compounds (flavonoids and related phenylpropanoids) and the resultant decrease in epidermal UV transmittance (TUV ) are primary protective mechanisms employed by plants against potentially damaging solar UV radiation and are critical components of the overall acclimation response of plants to changing solar UV environments. Whether plants can adjust this UV sunscreen protection in response to rapid changes in UV, as occurs on a diurnal basis, is largely unexplored. Here, we use a combination of approaches to demonstrate that plants can modulate their UV-screening properties within minutes to hours, and these changes are driven, in part, by UV radiation. For the cultivated species Abelmoschus esculentus, large (30-50%) and reversible changes in TUV occurred on a diurnal basis, and these adjustments were associated with changes in the concentrations of whole-leaf UV-absorbing compounds and several quercetin glycosides. Similar results were found for two other species (Vicia faba and Solanum lycopersicum), but no such changes were detected in Zea mays. These findings reveal a much more dynamic UV-protection mechanism than previously recognized, raise important questions concerning the costs and benefits of UV-protection strategies in plants and have practical implications for employing UV to enhance crop vigor and quality in controlled environments. © 2015 John Wiley & Sons Ltd.

  1. Rapid genetic and epigenetic alterations under intergeneric genomic shock in newly synthesized Chrysanthemum morifolium x Leucanthemum paludosum hybrids (Asteraceae).

    Science.gov (United States)

    Wang, Haibin; Jiang, Jiafu; Chen, Sumei; Qi, Xiangyu; Fang, Weimin; Guan, Zhiyong; Teng, Nianjun; Liao, Yuan; Chen, Fadi

    2014-01-01

    The Asteraceae family is at the forefront of the evolution due to frequent hybridization. Hybridization is associated with the induction of widespread genetic and epigenetic changes and has played an important role in the evolution of many plant taxa. We attempted the intergeneric cross Chrysanthemum morifolium × Leucanthemum paludosum. To obtain the success in cross, we have to turn to ovule rescue. DNA profiling of the amphihaploid and amphidiploid was investigated using amplified fragment length polymorphism, sequence-related amplified polymorphism, start codon targeted polymorphism, and methylation-sensitive amplification polymorphism (MSAP). Hybridization induced rapid changes at the genetic and the epigenetic levels. The genetic changes mainly involved loss of parental fragments and gaining of novel fragments, and some eliminated sequences possibly from the noncoding region of L. paludosum. The MSAP analysis indicated that the level of DNA methylation was lower in the amphiploid (∼45%) than in the parental lines (51.5-50.6%), whereas it increased after amphidiploid formation. Events associated with intergeneric genomic shock were a feature of C. morifolium × L. paludosum hybrid, given that the genetic relationship between the parental species is relatively distant. Our results provide genetic and epigenetic evidence for understanding genomic shock in wide crosses between species in Asteraceae and suggest a need to expand our current evolutionary framework to encompass a genetic/epigenetic dimension when seeking to understand wide crosses.

  2. Rapid Genetic and Epigenetic Alterations under Intergeneric Genomic Shock in Newly Synthesized Chrysanthemum morifolium × Leucanthemum paludosum Hybrids (Asteraceae)

    Science.gov (United States)

    Wang, Haibin; Jiang, Jiafu; Chen, Sumei; Qi, Xiangyu; Fang, Weimin; Guan, Zhiyong; Teng, Nianjun; Liao, Yuan; Chen, Fadi

    2014-01-01

    The Asteraceae family is at the forefront of the evolution due to frequent hybridization. Hybridization is associated with the induction of widespread genetic and epigenetic changes and has played an important role in the evolution of many plant taxa. We attempted the intergeneric cross Chrysanthemum morifolium × Leucanthemum paludosum. To obtain the success in cross, we have to turn to ovule rescue. DNA profiling of the amphihaploid and amphidiploid was investigated using amplified fragment length polymorphism, sequence-related amplified polymorphism, start codon targeted polymorphism, and methylation-sensitive amplification polymorphism (MSAP). Hybridization induced rapid changes at the genetic and the epigenetic levels. The genetic changes mainly involved loss of parental fragments and gaining of novel fragments, and some eliminated sequences possibly from the noncoding region of L. paludosum. The MSAP analysis indicated that the level of DNA methylation was lower in the amphiploid (∼45%) than in the parental lines (51.5–50.6%), whereas it increased after amphidiploid formation. Events associated with intergeneric genomic shock were a feature of C. morifolium × L. paludosum hybrid, given that the genetic relationship between the parental species is relatively distant. Our results provide genetic and epigenetic evidence for understanding genomic shock in wide crosses between species in Asteraceae and suggest a need to expand our current evolutionary framework to encompass a genetic/epigenetic dimension when seeking to understand wide crosses. PMID:24407856

  3. Alterations of neurochemical expression of the coeliac-superior mesenteric ganglion complex (CSMG) neurons supplying the prepyloric region of the porcine stomach following partial stomach resection.

    Science.gov (United States)

    Palus, Katarzyna; Całka, Jarosław

    2016-03-01

    The purpose of the present study was to determine the response of the porcine coeliac-superior mesenteric ganglion complex (CSMG) neurons projecting to the prepyloric area of the porcine stomach to peripheral neuronal damage following partial stomach resection. To identify the sympathetic neurons innervating the studied area of stomach, the neuronal retrograde tracer Fast Blue (FB) was applied to control and partial stomach resection (RES) groups. On the 22nd day after FB injection, following laparotomy, the partial resection of the previously FB-injected stomach prepyloric area was performed in animals of RES group. On the 28th day, all animals were re-anaesthetized and euthanized. The CSMG complex was then collected and processed for double-labeling immunofluorescence. In control animals, retrograde-labelled perikarya were immunoreactive to tyrosine hydroxylase (TH), dopamine β-hydroxylase (DβH), neuropeptide Y (NPY) and galanin (GAL). Partial stomach resection decreased the numbers of FB-positive neurons immunopositive for TH and DβH. However, the strong increase of NPY and GAL expression, as well as de novo-synthesis of neuronal nitric oxide synthase (nNOS) and leu5-Enkephalin (LENK) was noted in studied neurons. Furthermore, FB-positive neurons in all pigs were surrounded by a network of cocaine- and amphetamine-regulated transcript peptide (CART)-, calcitonin gene-related peptide (CGRP)-, and substance P (SP)-, vasoactive intestinal peptide (VIP)-, LENK- and nNOS- immunoreactive nerve fibers. This may suggest neuroprotective contribution of these neurotransmitters in traumatic responses of sympathetic neurons to peripheral axonal damage. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Altered neurite morphology and cholinergic function of induced pluripotent stem cell-derived neurons from a patient with Kleefstra syndrome and autism

    Science.gov (United States)

    Nagy, J; Kobolák, J; Berzsenyi, S; Ábrahám, Z; Avci, H X; Bock, I; Bekes, Z; Hodoscsek, B; Chandrasekaran, A; Téglási, A; Dezső, P; Koványi, B; Vörös, E T; Fodor, L; Szél, T; Németh, K; Balázs, A; Dinnyés, A; Lendvai, B; Lévay, G; Román, V

    2017-01-01

    The aim of the present study was to establish an in vitro Kleefstra syndrome (KS) disease model using the human induced pluripotent stem cell (hiPSC) technology. Previously, an autism spectrum disorder (ASD) patient with Kleefstra syndrome (KS-ASD) carrying a deleterious premature termination codon mutation in the EHMT1 gene was identified. Patient specific hiPSCs generated from peripheral blood mononuclear cells of the KS-ASD patient were differentiated into post-mitotic cortical neurons. Lower levels of EHMT1 mRNA as well as protein expression were confirmed in these cells. Morphological analysis on neuronal cells differentiated from the KS-ASD patient-derived hiPSC clones showed significantly shorter neurites and reduced arborization compared to cells generated from healthy controls. Moreover, density of dendritic protrusions of neuronal cells derived from KS-ASD hiPSCs was lower than that of control cells. Synaptic connections and spontaneous neuronal activity measured by live cell calcium imaging could be detected after 5 weeks of differentiation, when KS-ASD cells exhibited higher sensitivity of calcium responses to acetylcholine stimulation indicating a lower nicotinic cholinergic tone at baseline condition in KS-ASD cells. In addition, gene expression profiling of differentiated neuronal cells from the KS-ASD patient revealed higher expression of proliferation-related genes and lower mRNA levels of genes involved in neuronal maturation and migration. Our data demonstrate anomalous neuronal morphology, functional activity and gene expression in KS-ASD patient-specific hiPSC-derived neuronal cultures, which offers an in vitro system that contributes to a better understanding of KS and potentially other neurodevelopmental disorders including ASD. PMID:28742076

  5. Cocaine causes deficits in radial migration and alters the distribution of glutamate and GABA neurons in the developing rat cerebral cortex.

    Science.gov (United States)

    Lee, Chun-Ting; Chen, Jia; Worden, Lila T; Freed, William J

    2011-01-01

    Prenatal cocaine exposure induces cytoarchitectural changes in the embryonic neocortex; however, the biological mechanisms and type of cortical neurons involved in these changes are not known. Previously, we found that neural progenitor proliferation in the neocortical ventricular zone (VZ) is inhibited by cocaine; here, we examine the changes in cortical neurogenesis and migration of glutamate and GABA neurons induced by prenatal cocaine exposure. Pregnant rats received 20 mg/kg of cocaine intraperitoneally twice at an interval of 12 h during three periods of neocortical neurogenesis. Neocortical area and distribution of developing neurons were examined by counting Tuj1+, glutamate+, or GABA+ cells in different areas of the cerebral cortex. Cocaine decreased neocortical area by reducing the size of the Tuj1+ layer, but only when administered during early periods of neocortical neurogenesis. The number of glutamatergic neurons was increased in the VZ but was decreased in the outer cortical laminae. Although the number of GABA+ neurons in the VZ of both the neocortex and ganglionic eminences was unchanged, GABA+ cells decreased in all other neocortical laminae. Tangential migration of GABA+ cells was also disrupted by cocaine. These findings suggest that in utero cocaine exposure disturbs radial migration of neocortical neurons, possibly because of decreased radial glia guiding support through enhanced differentiation of neocortical VZ progenitors. Cocaine interrupts radial migration of both glutamatergic and GABAergic neurons within the neocortex, in addition to the tangential migration of GABAergic neurons from the subcortical telecephalon. This may result in abnormal neocortical cytoarchitecture and concomitant adverse functional effects. Copyright © 2010 Wiley-Liss, Inc.

  6. Altered composition of bone as triggered by irradiation facilitates the rapid erosion of the matrix by both cellular and physicochemical processes.

    Directory of Open Access Journals (Sweden)

    Danielle E Green

    Full Text Available Radiation rapidly undermines trabecular architecture, a destructive process which proceeds despite a devastated cell population. In addition to the 'biologically orchestrated' resorption of the matrix by osteoclasts, physicochemical processes enabled by a damaged matrix may contribute to the rapid erosion of bone quality. 8w male C57BL/6 mice exposed to 5 Gy of Cs(137 γ-irradiation were compared to age-matched control at 2d, 10d, or 8w following exposure. By 10d, irradiation had led to significant loss of trabecular bone volume fraction. Assessed by reflection-based Fourier transform infrared imaging (FTIRI, chemical composition of the irradiated matrix indicated that mineralization had diminished at 2d by -4.3±4.8%, and at 10d by -5.8±3.2%. These data suggest that irradiation facilitates the dissolution of the matrix through a change in the material itself, a conclusion supported by a 13.7±4.5% increase in the elastic modulus as measured by nanoindentation. The decline in viable cells within the marrow of irradiated mice at 2d implies that the immediate collapse of bone quality and inherent increased risk of fracture is not solely a result of an overly-active biologic process, but one fostered by alterations in the material matrix that predisposes the material to erosion.

  7. Glycosylation alters steady-state inactivation of sodium channel Nav1.9/NaN in dorsal root ganglion neurons and is developmentally regulated.

    Science.gov (United States)

    Tyrrell, L; Renganathan, M; Dib-Hajj, S D; Waxman, S G

    2001-12-15

    Na channel NaN (Na(v)1.9) produces a persistent TTX-resistant (TTX-R) current in small-diameter neurons of dorsal root ganglia (DRG) and trigeminal ganglia. Na(v)1.9-specific antibodies react in immunoblot assays with a 210 kDa protein from the membrane fractions of adult DRG and trigeminal ganglia. The size of the immunoreactive protein is in close agreement with the predicted Na(v)1.9 theoretical molecular weight of 201 kDa, suggesting limited glycosylation of this channel in adult tissues. Neonatal rat DRG membrane fractions, however, contain an additional higher molecular weight immunoreactive protein. Reverse transcription-PCR analysis did not show additional longer transcripts that could encode the larger protein. Enzymatic deglycosylation of the membrane preparations converted both immunoreactive proteins into a single faster migrating band, consistent with two states of glycosylation of Na(v)1.9. The developmental change in the glycosylation state of Na(v)1.9 is paralleled by a developmental change in the gating of the persistent TTX-R Na(+) current attributable to Na(v)1.9 in native DRG neurons. Whole-cell patch-clamp analysis demonstrates that the midpoint of steady-state inactivation is shifted 7 mV in a hyperpolarized direction in neonatal (postnatal days 0-3) compared with adult DRG neurons, although there is no significant difference in activation. Pretreatment of neonatal DRG neurons with neuraminidase causes an 8 mV depolarizing shift in the midpoint of steady-state inactivation of Na(v)1.9, making it indistinguishable from that of adult DRG neurons. Our data show that extensive glycosylation of rat Na(v)1.9 is developmentally regulated and changes a critical property of this channel in native neurons.

  8. Rapid generation of sub-type, region-specific neurons and neural networks from human pluripotent stem cell-derived neurospheres

    Directory of Open Access Journals (Sweden)

    Aynun N. Begum

    2015-11-01

    Full Text Available Stem cell-based neuronal differentiation has provided a unique opportunity for disease modeling and regenerative medicine. Neurospheres are the most commonly used neuroprogenitors for neuronal differentiation, but they often clump in culture, which has always represented a challenge for neurodifferentiation. In this study, we report a novel method and defined culture conditions for generating sub-type or region-specific neurons from human embryonic and induced pluripotent stem cells derived neurosphere without any genetic manipulation. Round and bright-edged neurospheres were generated in a supplemented knockout serum replacement medium (SKSRM with 10% CO2, which doubled the expression of the NESTIN, PAX6 and FOXG1 genes compared with those cultured with 5% CO2. Furthermore, an additional step (AdSTEP was introduced to fragment the neurospheres and facilitate the formation of a neuroepithelial-type monolayer that we termed the “neurosphederm”. The large neural tube-type rosette (NTTR structure formed from the neurosphederm, and the NTTR expressed higher levels of the PAX6, SOX2 and NESTIN genes compared with the neuroectoderm-derived neuroprogenitors. Different layers of cortical, pyramidal, GABAergic, glutamatergic, cholinergic neurons appeared within 27 days using the neurosphederm, which is a shorter period than in traditional neurodifferentiation-protocols (42–60 days. With additional supplements and timeline dopaminergic and Purkinje neurons were also generated in culture too. Furthermore, our in vivo results indicated that the fragmented neurospheres facilitated significantly better neurogenesis in severe combined immunodeficiency (SCID mouse brains compared with the non-fragmented neurospheres. Therefore, this neurosphere-based neurodifferentiation protocol is a valuable tool for studies of neurodifferentiation, neuronal transplantation and high throughput screening assays.

  9. Altered dendritic complexity affects firing properties of cortical layer 2/3 pyramidal neurons in mice lacking the 5-HT3A receptor.

    NARCIS (Netherlands)

    van der Velden, L.; van Hooft, J.A.; Chameau, P.

    2012-01-01

    We have previously shown that the serotonergic input on Cajal-Retzius cells, mediated by 5-HT3 receptors, plays an important role in the early postnatal maturation of the apical dendritic trees of layer 2/3 pyramidal neurons. We reported that knockout mice lacking the 5-HT(3A) receptor showed

  10. Prolonged Consumption of Sucrose in a Binge-Like Manner, Alters the Morphology of Medium Spiny Neurons in the Nucleus Accumbens Shell.

    Directory of Open Access Journals (Sweden)

    Paul M Klenowski

    2016-03-01

    Full Text Available The modern diet has become highly sweetened, resulting in unprecedented levels of sugar consumption, particularly among adolescents. While chronic long-term sugar intake is known to contribute to the development of metabolic disorders including obesity and type II diabetes, little is known regarding the direct consequences of long-term, binge-like sugar consumption on the brain. Because sugar can cause the release of dopamine in the nucleus accumbens (NAc similarly to drugs of abuse, we investigated changes in the morphology of neurons in this brain region following short- (4 weeks and long-term (12 weeks binge-like sucrose consumption using an intermittent two-bottle choice paradigm. We used Golgi-Cox staining to impregnate medium spiny neurons (MSNs from the NAc core and shell of short- and long-term sucrose consuming rats and compared these to age matched water controls. We show that prolonged binge-like sucrose consumption significantly decreased the total dendritic length of NAc shell MSNs compared to age-matched control rats. We also found that the restructuring of these neurons resulted primarily from reduced distal dendritic complexity. Conversely, we observed increased spine densities at the distal branch orders of NAc shell MSNs from long-term sucrose consuming rats. Combined, these results highlight the neuronal effects of prolonged binge-like intake of sucrose on NAc shell MSN morphology.

  11. Regular consumption of a silicic acid-rich water prevents aluminium-induced alterations of nitrergic neurons in mouse brain: histochemical and immunohistochemical studies.

    Science.gov (United States)

    Foglio, E; Buffoli, B; Exley, C; Rezzani, R; Rodella, L F

    2012-08-01

    Silicon is not generally considered an essential nutrient for mammals and, to date, whether it has a biological role or beneficial effects in humans is not known. The results of a number of studies suggest that dietary silicon supplementation might have a protective effect both for limiting aluminium absorption across the gut and for the removal of systemic aluminium via the urine, hence, preventing potential accumulation of aluminium in the brain. Since our previous studies demonstrated that aluminium exposure reduces the number of nitrergic neurons, the aim of the present study was to compare the distribution and the morphology of NO-containing neurons in brain cortex of mice exposed to aluminium sulphate dissolved in silicic acid-rich or poor drinking water to assess the potential protective role of silicon against aluminium toxicity in the brain. NADPH-d histochemistry and nNOS immunohistochemistry showed that high concentrations of silicon in drinking water were able to minimize the impairment of the function of nitrergic neurons induced by aluminium administration. We found that silicon protected against aluminium-induced damage to the nitrergic system: in particular, we demonstrated that silicon maintains the number of nitrergic neurons and their expression of nitrergic enzymes at physiological levels, even after a 12 and 15 month exposure to aluminium.

  12. Glia-to-neuron transfer of miRNAs via extracellular vesicles: a new mechanism underlying inflammation-induced synaptic alterations.

    Science.gov (United States)

    Prada, Ilaria; Gabrielli, Martina; Turola, Elena; Iorio, Alessia; D'Arrigo, Giulia; Parolisi, Roberta; De Luca, Mariacristina; Pacifici, Marco; Bastoni, Mattia; Lombardi, Marta; Legname, Giuseppe; Cojoc, Dan; Buffo, Annalisa; Furlan, Roberto; Peruzzi, Francesca; Verderio, Claudia

    2018-01-04

    Recent evidence indicates synaptic dysfunction as an early mechanism affected in neuroinflammatory diseases, such as multiple sclerosis, which are characterized by chronic microglia activation. However, the mode(s) of action of reactive microglia in causing synaptic defects are not fully understood. In this study, we show that inflammatory microglia produce extracellular vesicles (EVs) which are enriched in a set of miRNAs that regulate the expression of key synaptic proteins. Among them, miR-146a-5p, a microglia-specific miRNA not present in hippocampal neurons, controls the expression of presynaptic synaptotagmin1 (Syt1) and postsynaptic neuroligin1 (Nlg1), an adhesion protein which play a crucial role in dendritic spine formation and synaptic stability. Using a Renilla-based sensor, we provide formal proof that inflammatory EVs transfer their miR-146a-5p cargo to neuron. By western blot and immunofluorescence analysis we show that vesicular miR-146a-5p suppresses Syt1 and Nlg1 expression in receiving neurons. Microglia-to-neuron miR-146a-5p transfer and Syt1 and Nlg1 downregulation do not occur when EV-neuron contact is inhibited by cloaking vesicular phosphatidylserine residues and when neurons are exposed to EVs either depleted of miR-146a-5p, produced by pro-regenerative microglia, or storing inactive miR-146a-5p, produced by cells transfected with an anti-miR-146a-5p. Morphological analysis reveals that prolonged exposure to inflammatory EVs leads to significant decrease in dendritic spine density in hippocampal neurons in vivo and in primary culture, which is rescued in vitro by transfection of a miR-insensitive Nlg1 form. Dendritic spine loss is accompanied by a decrease in the density and strength of excitatory synapses, as indicated by reduced mEPSC frequency and amplitude. These findings link inflammatory microglia and enhanced EV production to loss of excitatory synapses, uncovering a previously unrecognized role for microglia-enriched miRNAs, released

  13. Rapid generation of functional dopaminergic neurons from human induced pluripotent stem cells through a single-step procedure using cell lineage transcription factors.

    Science.gov (United States)

    Theka, Ilda; Caiazzo, Massimiliano; Dvoretskova, Elena; Leo, Damiana; Ungaro, Federica; Curreli, Sebastiano; Managò, Francesca; Dell'Anno, Maria Teresa; Pezzoli, Gianni; Gainetdinov, Raul R; Dityatev, Alexander; Broccoli, Vania

    2013-06-01

    Current protocols for in vitro differentiation of human induced pluripotent stem cells (hiPSCs) to generate dopamine (DA) neurons are laborious and time-expensive. In order to accelerate the overall process, we have established a fast protocol by expressing the developmental transcription factors ASCL1, NURR1, and LMX1A. With this method, we were able to generate mature and functional dopaminergic neurons in as few as 21 days, skipping all the intermediate steps for inducting and selecting embryoid bodies and rosette-neural precursors. Strikingly, the resulting neuronal conversion process was very proficient, with an overall efficiency that was more than 93% of all the coinfected cells. hiPSC-derived DA neurons expressed all the critical molecular markers of the DA molecular machinery and exhibited sophisticated functional features including spontaneous electrical activity and dopamine release. This one-step protocol holds important implications for in vitro disease modeling and is particularly amenable for exploitation in high-throughput screening protocols.

  14. Peripheral drive in Aα/β-fiber neurons is altered in a rat model of osteoarthritis: changes in following frequency and recovery from inactivation

    Directory of Open Access Journals (Sweden)

    Wu Q

    2013-03-01

    Full Text Available Qi Wu, James L HenryDepartment of Psychiatry and Behavioral Neurosciences, McMaster University, Hamilton, ON, CanadaPurpose: To determine conduction fidelity of Aα/β-fiber low threshold mechanoreceptors in a model of osteoarthritis (OA.Methods: Four weeks after cutting the anterior cruciate ligament and removing the medial meniscus to induce the model, in vivo intracellular recordings were made in ipsilateral L4 dorsal root ganglion neurons. L4 dorsal roots were stimulated to determine the refractory interval and the maximum following frequency of the evoked action potential (AP. Neurons exhibited two types of response to paired pulse stimulation. Results: One type of response was characterized by fractionation of the evoked AP into an initial nonmyelinated-spike and a later larger-amplitude somatic-spike at shorter interstimulus intervals. The other type of response was characterized by an all-or-none AP, where the second evoked AP failed altogether at shorter interstimulus intervals. In OA versus control animals, the refractory interval measured in paired pulse testing was less in all low threshold mechanoreceptors. With train stimulation, the maximum rising rate of the nonmyelinated-spike was greater in OA nonmuscle spindle low threshold mechanoreceptors, possibly due to changes in fast kinetics of currents. Maximum following frequency in Pacinian and muscle spindle neurons was greater in model animals compared to controls. Train stimulation also induced an inactivation and fractionation of the AP in neurons that showed fractionation of the AP in paired pulse testing. However, with train stimulation this fractionation followed a different time course, suggesting more than one type of inactivation.Conclusion: The data suggest that joint damage can lead to changes in the fidelity of AP conduction of large diameter sensory neurons, muscle spindle neurons in particular, arising from articular and nonarticular tissues in OA animals compared to

  15. Genome-wide DNA methylation alterations of Alternanthera philoxeroides in natural and manipulated habitats: implications for epigenetic regulation of rapid responses to environmental fluctuation and phenotypic variation.

    Science.gov (United States)

    Gao, Lexuan; Geng, Yupeng; Li, Bo; Chen, Jiakuan; Yang, Ji

    2010-11-01

    Alternanthera philoxeroides (alligator weed) is an invasive weed that can colonize both aquatic and terrestrial habitats. Individuals growing in different habitats exhibit extensive phenotypic variation but little genetic differentiation in its introduced range. The mechanisms underpinning the wide range of phenotypic variation and rapid adaptation to novel and changing environments remain uncharacterized. In this study, we examined the epigenetic variation and its correlation with phenotypic variation in plants exposed to natural and manipulated environmental variability. Genome-wide methylation profiling using methylation-sensitive amplified fragment length polymorphism (MSAP) revealed considerable DNA methylation polymorphisms within and between natural populations. Plants of different source populations not only underwent significant morphological changes in common garden environments, but also underwent a genome-wide epigenetic reprogramming in response to different treatments. Methylation alterations associated with response to different water availability were detected in 78.2% (169/216) of common garden induced polymorphic sites, demonstrating the environmental sensitivity and flexibility of the epigenetic regulatory system. These data provide evidence of the correlation between epigenetic reprogramming and the reversible phenotypic response of alligator weed to particular environmental factors. © 2010 Blackwell Publishing Ltd.

  16. CACNA1H missense mutations associated with amyotrophic lateral sclerosis alter Cav3.2 T-type calcium channel activity and reticular thalamic neuron firing.

    Science.gov (United States)

    Rzhepetskyy, Yuriy; Lazniewska, Joanna; Blesneac, Iulia; Pamphlett, Roger; Weiss, Norbert

    2016-11-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. In a recent study by Steinberg and colleagues, 2 recessive missense mutations were identified in the Cav3.2 T-type calcium channel gene (CACNA1H), in a family with an affected proband (early onset, long duration ALS) and 2 unaffected parents. We have introduced and functionally characterized these mutations using transiently expressed human Cav3.2 channels in tsA-201 cells. Both of these mutations produced mild but significant changes on T-type channel activity that are consistent with a loss of channel function. Computer modeling in thalamic reticular neurons suggested that these mutations result in decreased neuronal excitability of thalamic structures. Taken together, these findings implicate CACNA1H as a susceptibility gene in amyotrophic lateral sclerosis.

  17. Intermittent fasting promotes prolonged associative interactions during synaptic tagging/capture by altering the metaplastic properties of the CA1 hippocampal neurons.

    Science.gov (United States)

    Dasgupta, Ananya; Kim, Joonki; Manakkadan, Anoop; Arumugam, Thiruma V; Sajikumar, Sreedharan

    2017-12-19

    Metaplasticity is the inherent property of a neuron or neuronal population to undergo activity-dependent changes in neural function that modulate subsequent synaptic plasticity. Here we studied the effect of intermittent fasting (IF) in governing the interactions of associative plasticity mechanisms in the pyramidal neurons of rat hippocampal area CA1. Late long-term potentiation and its associative mechanisms such as synaptic tagging and capture at an interval of 120 min were evaluated in four groups of animals, AL (Ad libitum), IF12 (daily IF for 12 h), IF16 (daily IF for 16 h) and EOD (every other day IF for 24 h). IF had no visible effect on the early or late plasticity but it manifested a critical role in prolonging the associative interactions between weak and strong synapses at an interval of 120 min in IF16 and EOD animals. However, both IF12 and AL did not show associativity at 120 min. Plasticity genes such as Bdnf and Prkcz, which are well known for their expressions in late plasticity and synaptic tagging and capture, were significantly upregulated in IF16 and EOD in comparison to AL. Specific inhibition of brain derived neurotropic factor (BDNF) prevented the prolonged associativity expressed in EOD. Thus, daily IF for 16 h or more can be considered to enhance the metaplastic properties of synapses by improving their associative interactions that might translate into animprovedmemoryformation. Copyright © 2017. Published by Elsevier Inc.

  18. Aluminum modulates effects of beta amyloid(1-42) on neuronal calcium homeostasis and mitochondria functioning and is altered in a triple transgenic mouse model of Alzheimer's disease.

    Science.gov (United States)

    Drago, Denise; Cavaliere, Alessandra; Mascetra, Nicola; Ciavardelli, Domenico; di Ilio, Carmine; Zatta, Paolo; Sensi, Stefano L

    2008-10-01

    Recent findings suggest that beta-amyloid (A beta) is more neurotoxic when present in its oligomeric configuration rather than as monomers or fibrils. Previous work from our laboratories has shown that A beta aggregation is strongly influenced by the conjugation of the peptide with metal ions (aluminum A, copper [Cu], zinc [Zn], and iron [Fe]) that are found in high concentrations in the core of senile plaques. Disruption of Ca++ signaling and mitochondrial dysfunction are potent triggers of neuronal death and have been implicated in the neuronal loss that is associated with Alzheimer's disease (AD). In this study, we explored whether A beta-metal complexes can have detrimental effects on intraneuronal Ca++ ([Ca++]i) homeostasis and mitochondrial function in vitro. Results from our experiments indicate that, when conjugated with Al, A beta perturbs neuronal [Ca++]i homeostasis and inhibits mitochondrial respiration. Finally, we analyzed the content of the four metals in the brain of a triple transgenic animal model of AD and found that Al is the only one to be increased in the cortex of these mice.

  19. Diverse impact of acute and long-term extracellular proteolytic activity on plasticity of neuronal excitability

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    Tomasz eWójtowicz

    2015-08-01

    Full Text Available Learning and memory require alteration in number and strength of existing synaptic connections. Extracellular proteolysis within the synapses has been shown to play a pivotal role in synaptic plasticity by determining synapse structure, function, and number. Although synaptic plasticity of excitatory synapses is generally acknowledged to play a crucial role in formation of memory traces, some components of neural plasticity are reflected by nonsynaptic changes. Since information in neural networks is ultimately conveyed with action potentials, scaling of neuronal excitability could significantly enhance or dampen the outcome of dendritic integration, boost neuronal information storage capacity and ultimately learning. However, the underlying mechanism is poorly understood. With this regard, several lines of evidence and our most recent study support a view that activity of extracellular proteases might affect information processing in neuronal networks by affecting targets beyond synapses. Here we review the most recent studies addressing the impact of extracellular proteolysis on plasticity of neuronal excitability and discuss how enzymatic activity may alter input-output/transfer function of neurons, supporting cognitive processes. Interestingly, extracellular proteolysis may alter intrinsic neuronal excitability and excitation/inhibition balance both rapidly (time of minutes to hours and in long-term window. Moreover, it appears that by cleavage of extracellular matrix constituents, proteases may modulate function of ion channels or alter inhibitory drive and hence facilitate active participation of dendrites and axon initial segments in adjusting neuronal input/output function. Altogether, a picture emerges whereby both rapid and long-term extracellular proteolysis may influence some aspects of information processing in neurons, such as initiation of action potential, spike frequency adaptation, properties of action potential and dendritic

  20. Nutritional Omega-3 Deficiency Alters Glucocorticoid Receptor-Signaling Pathway and Neuronal Morphology in Regionally Distinct Brain Structures Associated with Emotional Deficits

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    Thomas Larrieu

    2016-01-01

    Full Text Available Extensive evidence suggests that long term dietary n-3 polyunsaturated fatty acids (PUFAs deficiency results in altered emotional behaviour. We have recently demonstrated that n-3 PUFAs deficiency induces emotional alterations through abnormal corticosterone secretion which leads to altered dendritic arborisation in the prefrontal cortex (PFC. Here we show that hypothalamic-pituitary-adrenal (HPA axis feedback inhibition was not compromised in n-3 deficient mice. Rather, glucocorticoid receptor (GR signaling pathway was inactivated in the PFC but not in the hippocampus of n-3 deficient mice. Consequently, only dendritic arborisation in PFC was affected by dietary n-3 PUFAs deficiency. In addition, occlusion experiment with GR blockade altered GR signaling in the PFC of control mice, with no further alterations in n-3 deficient mice. In conclusion, n-3 PUFAs deficiency compromised PFC, leading to dendritic atrophy, but did not change hippocampal GR function and dendritic arborisation. We argue that this GR sensitivity contributes to n-3 PUFAs deficiency-related emotional behaviour deficits.

  1. Dietary Plant Lectins Appear to Be Transported from the Gut to Gain Access to and Alter Dopaminergic Neurons of Caenorhabditis elegans, a Potential Etiology of Parkinson's Disease.

    Science.gov (United States)

    Zheng, Jolene; Wang, Mingming; Wei, Wenqian; Keller, Jeffrey N; Adhikari, Binita; King, Jason F; King, Michael L; Peng, Nan; Laine, Roger A

    2016-01-01

    Lectins from dietary plants have been shown to enhance drug absorption in the gastrointestinal tract of rats, be transported trans-synaptically as shown by tracing of axonal and dendritic paths, and enhance gene delivery. Other carbohydrate-binding protein toxins are known to traverse the gut intact in dogs. Post-feeding rhodamine- or TRITC-tagged dietary lectins, the lectins were tracked from gut to dopaminergic neurons (DAergic-N) in transgenic Caenorhabditis elegans (C. elegans) [egIs1(Pdat-1:GFP)] where the mutant has the green fluorescent protein (GFP) gene fused to a dopamine transport protein gene labeling DAergic-N. The lectins were supplemented along with the food organism Escherichia coli (OP50). Among nine tested rhodamine/TRITC-tagged lectins, four, including Phaseolus vulgaris erythroagglutinin (PHA-E), Bandeiraea simplicifolia (BS-I), Dolichos biflorus agglutinin (DBA), and Arachis hypogaea agglutinin (PNA), appeared to be transported from gut to the GFP-DAergic-N. Griffonia Simplicifolia and PHA-E, reduced the number of GFP-DAergic-N, suggesting a toxic activity. PHA-E, BS-I, Pisum sativum (PSA), and Triticum vulgaris agglutinin (Succinylated) reduced fluorescent intensity of GFP-DAergic-N. PHA-E, PSA, Concanavalin A, and Triticum vulgaris agglutinin decreased the size of GFP-DAergic-N, while BS-I increased neuron size. These observations suggest that dietary plant lectins are transported to and affect DAergic-N in C. elegans, which support Braak and Hawkes' hypothesis, suggesting one alternate potential dietary etiology of Parkinson's disease (PD). A recent Danish study showed that vagotomy resulted in 40% lower incidence of PD over 20 years. Differences in inherited sugar structures of gut and neuronal cell surfaces may make some individuals more susceptible in this conceptual disease etiology model.

  2. Rapid Selection in Modified BHK-21 Cells of a Foot-and-Mouth Disease Virus Variant Showing Alterations in Cell Tropism

    Science.gov (United States)

    Escarmís, Cristina; Carrillo, Elisa C.; Ferrer, Marcela; Arriaza, Juan F. García; Lopez, Nora; Tami, Cecilia; Verdaguer, Nuria; Domingo, Esteban; Franze-Fernández, Maria T.

    1998-01-01

    With persistent foot-and-mouth disease virus (FMDV) in BHK-21 cells, there is coevolution of the cells and the resident virus; the virulence of the virus for the parental BHK-21 cells is gradually increased, and the cells become partially resistant to FMDV. Here we report that variants of FMDV C3Arg/85 were selected in a single infection of partially resistant BHK-21 cells (termed BHK-Rb cells). Indirect immunofluorescence showed that the BHK-Rb cell population was heterogeneous with regard to susceptibility to C3Arg/85 infection. Infection of BHK-Rb cells with C3Arg/85 resulted in an early phase of partial cytopathology which was followed at 6 to 10 days postinfection by the shedding of mutant FMDVs, termed C3-Rb. The selected C3-Rb variants showed increased virulence for BHK-21 cells, were able to overcome the resistance of modified BHK-21 cells to infection, and had acquired the ability to bind heparin and to infect wild-type Chinese hamster ovary (CHO) cells. A comparison of the genomic sequences of the parental and modified viruses revealed only two amino acid differences, located at the surface of the particle, at the fivefold axis of the viral capsid (Asp-9→Ala in VP3 and either Gly-110→Arg or His-108→Arg in VP1). The same phenotypic and genotypic modifications occurred in a highly reproducible manner; they were seen in a number of independent infections of BHK-Rb cells with viral preparation C3Arg/85 or with clones derived from it. Neither amino acid substitutions in other structural or nonstructural proteins nor nucleotide substitutions in regulatory regions were found. These results prove that infection of partially permissive cells can promote the rapid selection of virus variants that show alterations in cell tropism and are highly virulent for the same cells. PMID:9811758

  3. Selective regional alterations in the content or distribution of neuronal and glial cytoskeletal proteins in brain of rats chronically exposed to 2,5-hexanedione.

    Science.gov (United States)

    Hernandez-Viadel, Mari Luz; Rodrigo, Regina; Felipo, Vicente

    2002-08-01

    Hexane is used in many industrial processes and induces neurotoxic effects in the central and peripheral nervous system. Hexane is metabolized to 2,5-hexanedione, which is the neurotoxic agent. Continued exposure to hexane or 2,5-hexanedione results in loss of sensorial and motor function in arms and legs and to alterations in axonal neurofilament proteins. The effects of 2,5-hexanedione on different cytoskeletal proteins in different brain areas have not been studied in detail. The aim of this work was to study the effects of chronic exposure of rats to 2,5-hexanedione (1% in the drinking water) on tubulin, neurofilament NF-L, microtubule-associated protein MAP-2, and on glial fibrillary acidic protein (GFAP), in cerebellum, hippocampus and cerebral cortex. The amount of each protein was determined by immunoblotting and its distribution was analysed by immunohistochemistry. The results obtained show a regional selectivity in the 2,5-hexanedione effects on cytoskeletal proteins. NF-L content decreased in all brain areas. MAP-2 decreased in cerebellum and hippocampus and tubulin decreased only in cerebellum. GFAP decreased only in cerebral cortex, but its distribution was altered in cerebellum, with increased content in the granular layer and decreased content in the molecular layer. The area most affected was the cerebellum, where all the proteins analysed were altered. These cytoskeletal proteins alterations may impair the transfer of information involved in the regulation by the cerebellum of motor function and contribute to the altered motor performance in rats exposed to 2,5-hexanedione and humans exposed to hexane.

  4. Xenon Reduces Neuronal Hippocampal Damage and Alters the Pattern of Microglial Activation after Experimental Subarachnoid Hemorrhage: A Randomized Controlled Animal Trial

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    Michael Veldeman

    2017-09-01

    Full Text Available ObjectiveThe neuroprotective properties of the noble gas xenon have already been demonstrated using a variety of injury models. Here, we examine for the first time xenon’s possible effect in attenuating early brain injury (EBI and its influence on posthemorrhagic microglial neuroinflammation in an in vivo rat model of subarachnoid hemorrhage (SAH.MethodsSprague-Dawley rats (n = 22 were randomly assigned to receive either Sham surgery (n = 9; divided into two groups or SAH induction via endovascular perforation (n = 13, divided into two groups. Of those randomized for SAH, 7 animals were postoperatively ventilated with 50 vol% oxygen/50 vol% xenon for 1 h and 6 received 50 vol% oxygen/50 vol% nitrogen (control. The animals were sacrificed 24 h after SAH. Of each animal, a cerebral coronal section (−3.60 mm from bregma was selected for assessment of histological damage 24 h after SAH. A 5-point neurohistopathological severity score was applied to assess neuronal cell damage in H&E and NeuN stained sections in a total of four predefined anatomical regions of interest. Microglial activation was evaluated by a software-assisted cell count of Iba-1 stained slices in three cortical regions of interest.ResultsA diffuse cellular damage was apparent in all regions of the ipsilateral hippocampus 24 h after SAH. Xenon-treated animals presented with a milder damage after SAH. This effect was found to be particularly pronounced in the medial regions of the hippocampus, CA3 (p = 0.040, and dentate gyrus (DG p = 0.040. However, for the CA1 and CA2 regions, there were no statistical differences in neuronal damage according to our histological scoring. A cell count of activated microglia was lower in the cortex of xenon-treated animals. This difference was especially apparent in the left piriform cortex (p = 0.017.ConclusionIn animals treated with 50 vol% xenon (for 1 h after SAH, a less pronounced neuronal damage was

  5. Genomic and Phenotypic Alterations of the Neuronal-Like Cells Derived from Human Embryonal Carcinoma Stem Cells (NT2 Caused by Exposure to Organophosphorus Compounds Paraoxon and Mipafox

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    David Pamies

    2014-01-01

    Full Text Available Historically, only few chemicals have been identified as neurodevelopmental toxicants, however, concern remains, and has recently increased, based upon the association between chemical exposures and increased developmental disorders. Diminution in motor speed and latency has been reported in preschool children from agricultural communities. Organophosphorus compounds (OPs are pesticides due to their acute insecticidal effects mediated by the inhibition of acetylcholinesterase, although other esterases as neuropathy target esterase (NTE can also be inhibited. Other neurological and neurodevelopmental toxic effects with unknown targets have been reported after chronic exposure to OPs in vivo. We studied the initial stages of retinoic acid acid-triggered differentiation of pluripotent cells towards neural progenitors derived from human embryonal carcinoma stem cells to determine if neuropathic OP, mipafox, and non-neuropathic OP, paraoxon, are able to alter differentiation of neural precursor cells in vitro. Exposure to 1 µM paraoxon (non-cytotoxic concentrations altered the expression of different genes involved in signaling pathways related to chromatin assembly and nucleosome integrity. Conversely, exposure to 5 µM mipafox, a known inhibitor of NTE activity, showed no significant changes on gene expression. We conclude that 1 µM paraoxon could affect the initial stage of in vitro neurodifferentiation possibly due to a teratogenic effect, while the absence of transcriptional alterations by mipafox exposure did not allow us to conclude a possible effect on neurodifferentiation pathways at the tested concentration.

  6. Neurological and behavioral abnormalities, ventricular dilatation, altered cellular functions, inflammation, and neuronal injury in brains of mice due to common, persistent, parasitic infection.

    Science.gov (United States)

    Hermes, Gretchen; Ajioka, James W; Kelly, Krystyna A; Mui, Ernest; Roberts, Fiona; Kasza, Kristen; Mayr, Thomas; Kirisits, Michael J; Wollmann, Robert; Ferguson, David J P; Roberts, Craig W; Hwang, Jong-Hee; Trendler, Toria; Kennan, Richard P; Suzuki, Yasuhiro; Reardon, Catherine; Hickey, William F; Chen, Lieping; McLeod, Rima

    2008-10-23

    Worldwide, approximately two billion people are chronically infected with Toxoplasma gondii with largely unknown consequences. To better understand long-term effects and pathogenesis of this common, persistent brain infection, mice were infected at a time in human years equivalent to early to mid adulthood and studied 5-12 months later. Appearance, behavior, neurologic function and brain MRIs were studied. Additional analyses of pathogenesis included: correlation of brain weight and neurologic findings; histopathology focusing on brain regions; full genome microarrays; immunohistochemistry characterizing inflammatory cells; determination of presence of tachyzoites and bradyzoites; electron microscopy; and study of markers of inflammation in serum. Histopathology in genetically resistant mice and cytokine and NRAMP knockout mice, effects of inoculation of isolated parasites, and treatment with sulfadiazine or alphaPD1 ligand were studied. Twelve months after infection, a time equivalent to middle to early elderly ages, mice had behavioral and neurological deficits, and brain MRIs showed mild to moderate ventricular dilatation. Lower brain weight correlated with greater magnitude of neurologic abnormalities and inflammation. Full genome microarrays of brains reflected inflammation causing neuronal damage (Gfap), effects on host cell protein processing (ubiquitin ligase), synapse remodeling (Complement 1q), and also increased expression of PD-1L (a ligand that allows persistent LCMV brain infection) and CD 36 (a fatty acid translocase and oxidized LDL receptor that mediates innate immune response to beta amyloid which is associated with pro-inflammation in Alzheimer's disease). Immunostaining detected no inflammation around intra-neuronal cysts, practically no free tachyzoites, and only rare bradyzoites. Nonetheless, there were perivascular, leptomeningeal inflammatory cells, particularly contiguous to the aqueduct of Sylvius and hippocampus, CD4+ and CD8+ T cells

  7. Neurological and behavioral abnormalities, ventricular dilatation, altered cellular functions, inflammation, and neuronal injury in brains of mice due to common, persistent, parasitic infection

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    Hwang Jong-Hee

    2008-10-01

    Full Text Available Abstract Background Worldwide, approximately two billion people are chronically infected with Toxoplasma gondii with largely unknown consequences. Methods To better understand long-term effects and pathogenesis of this common, persistent brain infection, mice were infected at a time in human years equivalent to early to mid adulthood and studied 5–12 months later. Appearance, behavior, neurologic function and brain MRIs were studied. Additional analyses of pathogenesis included: correlation of brain weight and neurologic findings; histopathology focusing on brain regions; full genome microarrays; immunohistochemistry characterizing inflammatory cells; determination of presence of tachyzoites and bradyzoites; electron microscopy; and study of markers of inflammation in serum. Histopathology in genetically resistant mice and cytokine and NRAMP knockout mice, effects of inoculation of isolated parasites, and treatment with sulfadiazine or αPD1 ligand were studied. Results Twelve months after infection, a time equivalent to middle to early elderly ages, mice had behavioral and neurological deficits, and brain MRIs showed mild to moderate ventricular dilatation. Lower brain weight correlated with greater magnitude of neurologic abnormalities and inflammation. Full genome microarrays of brains reflected inflammation causing neuronal damage (Gfap, effects on host cell protein processing (ubiquitin ligase, synapse remodeling (Complement 1q, and also increased expression of PD-1L (a ligand that allows persistent LCMV brain infection and CD 36 (a fatty acid translocase and oxidized LDL receptor that mediates innate immune response to beta amyloid which is associated with pro-inflammation in Alzheimer's disease. Immunostaining detected no inflammation around intra-neuronal cysts, practically no free tachyzoites, and only rare bradyzoites. Nonetheless, there were perivascular, leptomeningeal inflammatory cells, particularly contiguous to the aqueduct of

  8. Running wheel exercise reduces renewal of extinguished instrumental behavior and alters medial prefrontal cortex neurons in adolescent, but not adult, rats.

    Science.gov (United States)

    Eddy, Meghan C; Green, John T

    2017-12-01

    Physical exercise in rodents has repeatedly been shown to trigger positive effects on brain function, including increased neurotrophic factors and improved learning and memory. However, most of this work has focused on the adult hippocampus and hippocampal-dependent behavior. Here we examined the effect of running wheel exercise in adult and adolescent male rats on ABA renewal of extinguished instrumental conditioning, in which acquisition occurs in Context A, extinction in Context B, and renewal testing occurs back in Context A. In the first experiment, rats were given unlocked (exercise) or locked (no exercise) running wheel access in their home cages beginning at postnatal Day 30 (adolescent) or postnatal Day 56 (adult). Rats underwent lever-press acquisition in Context A and extinction in Context B. ABA renewal testing took place 2 weeks after the start of running wheel exposure. Nonexercising adolescent rats showed greater ABA renewal than nonexercising adult rats and exercise reduced ABA renewal in adolescents but not adults. ABA renewal depends on medial prefrontal cortex function. In a second experiment, we compared adolescent and adult apical dendrite branch length, branch number, and spine density of medial prefrontal cortex pyramidal neurons after 2 weeks of unlocked or locked running wheel access. The results revealed a higher density of dendritic spines and a lower dendritic branch length in adolescent exercisers than adolescent nonexercisers. Adult exercisers and nonexercisers did not differ. Collectively, these experiments suggest that exercise may have particularly strong effects on adolescent medial prefrontal cortex function and structure. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Long-lasting alterations in membrane properties, K+ currents and glutamatergic synaptic currents of nucleus accumbens medium spiny neurons in a rat model of alcohol dependence

    Directory of Open Access Journals (Sweden)

    Igor eSpigelman

    2012-06-01

    Full Text Available Chronic alcohol exposure causes marked changes in reinforcement mechanisms and motivational state that are thought to contribute to the development of cravings and relapse during protracted withdrawal. The nucleus accumbens (NAcc is a key structure of the mesolimbic dopaminergic reward system. Although the NAcc plays an important role in mediating alcohol-seeking behaviors, little is known about the molecular mechanisms underlying alcohol-induced neuroadaptive changes in NAcc function. The aim of this study was to investigate the effects of chronic intermittent ethanol (CIE treatment, a rat model of alcohol withdrawal and dependence, on intrinsic electrical membrane properties and glutamatergic synaptic transmission of medium spiny neurons (MSNs in the NAcc core during protracted withdrawal. We show that CIE treatment followed by prolonged withdrawal increased the inward rectification of MSNs observed at hyperpolarized potentials. In addition, MSNs from CIE-treated animals displayed a lower input resistance, faster action potentials (APs and larger fast afterhyperpolarizations (fAHPs than MSNs from vehicle-treated animals, all suggestive of increases in K+-channel conductances. Significant increases in the Cs+-sensitive inwardly-rectifying K+-current accounted for the increased input resistance, while increases in the A-type K+-current accounted for the faster APs and increased fAHPs in MSNs from CIE rats. We also show that the amplitude and the conductance of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR-mediated mEPSCs were enhanced in CIE-treated animals due to an increase in a small fraction of functional postsynaptic GluA2-lacking AMPARs. These long-lasting modifications of excitability and excitatory synaptic receptor function of MSNs in the NAcc core could play a critical role in the neuroadaptive changes underlying alcohol withdrawal and dependence.

  10. Dynamics of Seedling Growth Acclimation towards Altered Light Conditions Can Be Quantified via GROWSCREEN: A Setup and Procedure Designed for Rapid Optical Phenotyping of Different Plant Species

    National Research Council Canada - National Science Library

    Achim Walter; Hanno Scharr; Frank Gilmer; Rainer Zierer; Kerstin A. Nagel; Michaela Ernst; Anika Wiese; Olivia Virnich; Maja M. Christ; Beate Uhlig; Sybille Jünger; Uli Schurr

    2007-01-01

    Using a novel setup, we assessed how fast growth of Nicotiana tabacum seedlings responds to alterations in the light regime and investigated whether starch-free mutants of Arabidopsis thaliana show...

  11. Altered learning, memory, and social behavior in type 1 taste receptor subunit 3 knock-out mice are associated with neuronal dysfunction.

    Science.gov (United States)

    Martin, Bronwen; Wang, Rui; Cong, Wei-Na; Daimon, Caitlin M; Wu, Wells W; Ni, Bin; Becker, Kevin G; Lehrmann, Elin; Wood, William H; Zhang, Yongqing; Etienne, Harmonie; van Gastel, Jaana; Azmi, Abdelkrim; Janssens, Jonathan; Maudsley, Stuart

    2017-07-07

    The type 1 taste receptor member 3 (T1R3) is a G protein-coupled receptor involved in sweet-taste perception. Besides the tongue, the T1R3 receptor is highly expressed in brain areas implicated in cognition, including the hippocampus and cortex. As cognitive decline is often preceded by significant metabolic or endocrinological dysfunctions regulated by the sweet-taste perception system, we hypothesized that a disruption of the sweet-taste perception in the brain could have a key role in the development of cognitive dysfunction. To assess the importance of the sweet-taste receptors in the brain, we conducted transcriptomic and proteomic analyses of cortical and hippocampal tissues isolated from T1R3 knock-out (T1R3KO) mice. The effect of an impaired sweet-taste perception system on cognition functions were examined by analyzing synaptic integrity and performing animal behavior on T1R3KO mice. Although T1R3KO mice did not present a metabolically disrupted phenotype, bioinformatic interpretation of the high-dimensionality data indicated a strong neurodegenerative signature associated with significant alterations in pathways involved in neuritogenesis, dendritic growth, and synaptogenesis. Furthermore, a significantly reduced dendritic spine density was observed in T1R3KO mice together with alterations in learning and memory functions as well as sociability deficits. Taken together our data suggest that the sweet-taste receptor system plays an important neurotrophic role in the extralingual central nervous tissue that underpins synaptic function, memory acquisition, and social behavior. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Vasculo-Neuronal Coupling: Retrograde Vascular Communication to Brain Neurons.

    Science.gov (United States)

    Kim, Ki Jung; Ramiro Diaz, Juan; Iddings, Jennifer A; Filosa, Jessica A

    2016-12-14

    Continuous cerebral blood flow is essential for neuronal survival, but whether vascular tone influences resting neuronal function is not known. Using a multidisciplinary approach in both rat and mice brain slices, we determined whether flow/pressure-evoked increases or decreases in parenchymal arteriole vascular tone, which result in arteriole constriction and dilation, respectively, altered resting cortical pyramidal neuron activity. We present evidence for intercellular communication in the brain involving a flow of information from vessel to astrocyte to neuron, a direction opposite to that of classic neurovascular coupling and referred to here as vasculo-neuronal coupling (VNC). Flow/pressure increases within parenchymal arterioles increased vascular tone and simultaneously decreased resting pyramidal neuron firing activity. On the other hand, flow/pressure decreases evoke parenchymal arteriole dilation and increased resting pyramidal neuron firing activity. In GLAST-CreERT2; R26-lsl-GCaMP3 mice, we demonstrate that increased parenchymal arteriole tone significantly increased intracellular calcium in perivascular astrocyte processes, the onset of astrocyte calcium changes preceded the inhibition of cortical pyramidal neuronal firing activity. During increases in parenchymal arteriole tone, the pyramidal neuron response was unaffected by blockers of nitric oxide, GABAA, glutamate, or ecto-ATPase. However, VNC was abrogated by TRPV4 channel, GABAB, as well as an adenosine A1 receptor blocker. Differently to pyramidal neuron responses, increases in flow/pressure within parenchymal arterioles increased the firing activity of a subtype of interneuron. Together, these data suggest that VNC is a complex constitutive active process that enables neurons to efficiently adjust their resting activity according to brain perfusion levels, thus safeguarding cellular homeostasis by preventing mismatches between energy supply and demand. We present evidence for vessel-to-neuron

  13. Retinal Layers Changes in Human Preclinical and Early Clinical Diabetic Retinopathy Support Early Retinal Neuronal and Müller Cells Alterations

    Directory of Open Access Journals (Sweden)

    Stela Vujosevic

    2013-01-01

    Full Text Available Purpose. To evaluate the changes in thickness of individual inner and outer macular and peripapillary retinal layers in diabetes. Methods. 124 subjects (124 eyes were enrolled: 74 diabetics and 50 controls. Macular edema, proliferative diabetic retinopathy (DR, any intraocular treatment and refractive error >6 diopters were the main exclusion criteria. Full ophthalmic examination, stereoscopic fundus photography, and spectral domain-OCT were performed. After automatic retinal segmentation (layering in 5 layers, the thickness of each layer was calculated, and values compared among groups. Results. Thirty patients had no DR, 44 patients had non proliferative DR. A significant increase of inner plexiform and nuclear layers was found in DR eyes versus controls (P<0.001. A significant decrease (P<0.01 of retinal nerve fiber layer (RNFL and at specific sites of retinal ganglion cell layer (P=0.02 was documented in the macula. In the peripapillary area there were no differences between diabetics and controls. Conclusions. Decreased RNFL thickness and increased INL/OPL thickness in diabetics without DR or with initial DR suggest early alterations in the inner retina. On the contrary, the outer retina seems not to be affected at early stages of DM. Automatic intraretinal layering by SD-OCT may be a useful tool to diagnose and monitor early intraretinal changes in DR.

  14. Axonal dynamics of excitatory and inhibitory neurons in somatosensory cortex.

    Directory of Open Access Journals (Sweden)

    Sally A Marik

    2010-06-01

    Full Text Available Cortical topography can be remapped as a consequence of sensory deprivation, suggesting that cortical circuits are continually modified by experience. To see the effect of altered sensory experience on specific components of cortical circuits, we imaged neurons, labeled with a genetically modified adeno-associated virus, in the intact mouse somatosensory cortex before and after whisker plucking. Following whisker plucking we observed massive and rapid reorganization of the axons of both excitatory and inhibitory neurons, accompanied by a transient increase in bouton density. For horizontally projecting axons of excitatory neurons there was a net increase in axonal projections from the non-deprived whisker barrel columns into the deprived barrel columns. The axon collaterals of inhibitory neurons located in the deprived whisker barrel columns retracted in the vicinity of their somata and sprouted long-range projections beyond their normal reach towards the non-deprived whisker barrel columns. These results suggest that alterations in the balance of excitation and inhibition in deprived and non-deprived barrel columns underlie the topographic remapping associated with sensory deprivation.

  15. Structural and Functional Alterations in Neocortical Circuits after Mild Traumatic Brain Injury

    Science.gov (United States)

    Vascak, Michal

    National concern over traumatic brain injury (TBI) is growing rapidly. Recent focus is on mild TBI (mTBI), which is the most prevalent injury level in both civilian and military demographics. A preeminent sequelae of mTBI is cognitive network disruption. Advanced neuroimaging of mTBI victims supports this premise, revealing alterations in activation and structure-function of excitatory and inhibitory neuronal systems, which are essential for network processing. However, clinical neuroimaging cannot resolve the cellular and molecular substrates underlying such changes. Therefore, to understand the full scope of mTBI-induced alterations it is necessary to study cortical networks on the microscopic level, where neurons form local networks that are the fundamental computational modules supporting cognition. Recently, in a well-controlled animal model of mTBI, we demonstrated in the excitatory pyramidal neuron system, isolated diffuse axonal injury (DAI), in concert with electrophysiological abnormalities in nearby intact (non-DAI) neurons. These findings were consistent with altered axon initial segment (AIS) intrinsic activity functionally associated with structural plasticity, and/or disturbances in extrinsic systems related to parvalbumin (PV)-expressing interneurons that form GABAergic synapses along the pyramidal neuron perisomatic/AIS domains. The AIS and perisomatic GABAergic synapses are domains critical for regulating neuronal activity and E-I balance. In this dissertation, we focus on the neocortical excitatory pyramidal neuron/inhibitory PV+ interneuron local network following mTBI. Our central hypothesis is that mTBI disrupts neuronal network structure and function causing imbalance of excitatory and inhibitory systems. To address this hypothesis we exploited transgenic and cre/lox mouse models of mTBI, employing approaches that couple state-of-the-art bioimaging with electrophysiology to determine the structuralfunctional alterations of excitatory and

  16. Noisy Neurons

    Indian Academy of Sciences (India)

    IAS Admin

    Nerves are fibres that conduct electrical signals and hence pass on information from and to the brain. Nerves are made of nerve cells called neurons (Figure 1). Instructions in our body are sent via electrical signals that present themselves as variations in the potential across neuronal membranes. These potential differences ...

  17. Motor Neurons

    DEFF Research Database (Denmark)

    Hounsgaard, Jorn

    2017-01-01

    Motor neurons translate synaptic input from widely distributed premotor networks into patterns of action potentials that orchestrate motor unit force and motor behavior. Intercalated between the CNS and muscles, motor neurons add to and adjust the final motor command. The identity and functional...

  18. Steroid Treatment Reduces Allergic Airway Inflammation and Does Not Alter the Increased Numbers of Dendritic Cells and Calcitonin Gene-Related Peptide-Expressing Neurons in Airway Sensory Ganglia.

    Science.gov (United States)

    Le, Duc Dung; Funck, Ulrike; Wronski, Sabine; Heck, Sebastian; Tschernig, Thomas; Bischoff, Markus; Sester, Martina; Herr, Christian; Bals, Robert; Welte, Tobias; Braun, Armin; Dinh, Quoc Thai

    2016-01-01

    Our previous data demonstrated that allergic airway inflammation induces migration of dendritic cells (DC) into airway sensory jugular and nodose ganglia (jugular-nodose ganglion complex; JNC). Here we investigated the effects of steroid treatment regarding the expression and migration of DC and calcitonin gene-related peptide (CGRP)-immunoreactive neurons of vagal sensory ganglia during allergic airway inflammation. A house dust mite (HDM) model for allergic airway inflammation was used. The mice received 0.3 mg fluticasone propionate per kilogram of body weight in the last 9 days. JNC slices were analyzed on MHC II, the neuronal marker PGP9.5, and the neuropeptide CGRP. Allergic airway inflammation increased the numbers of DC and CGRP-expressing neurons in the JNC significantly in comparison to the controls (DC/neurons: HDM 44.58 ± 1.6% vs. saline 33.29 ± 1.6%, p neurons/total neurons: HDM 30.65 ± 1.9% vs. saline 19.49 ± 2.3%, p neurons in the JNC compared to HDM-treated mice. The present findings indicate an important role of DC and CGRP-containing neurons in the pathogenesis of allergic airway inflammation. However, steroid treatment did not have an effect on the population of DC and neurons displaying CGRP in the JNC, whereas steroid treatment was found to suppress allergic airway inflammation. © 2015 S. Karger AG, Basel.

  19. The special relationship: glia-neuron interactions in the neuroendocrine hypothalamus.

    Science.gov (United States)

    Clasadonte, Jerome; Prevot, Vincent

    2018-01-01

    Natural fluctuations in physiological conditions require adaptive responses involving rapid and reversible structural and functional changes in the hypothalamic neuroendocrine circuits that control homeostasis. Here, we discuss the data that implicate hypothalamic glia in the control of hypothalamic neuroendocrine circuits, specifically neuron-glia interactions in the regulation of neurosecretion as well as neuronal excitability. Mechanistically, the morphological plasticity displayed by distal processes of astrocytes, pituicytes and tanycytes modifies the geometry and diffusion properties of the extracellular space. These changes alter the relationship between glial cells of the hypothalamus and adjacent neuronal elements, especially at specialized intersections such as synapses and neurohaemal junctions. The structural alterations in turn lead to functional plasticity that alters the release and spread of neurotransmitters, neuromodulators and gliotransmitters, as well as the activity of discrete glial signalling pathways that mediate feedback by peripheral signals to the hypothalamus. An understanding of the contributions of these and other non-neuronal cell types to hypothalamic neuroendocrine function is thus critical both to understand physiological processes such as puberty, the maintenance of bodily homeostasis and ageing and to develop novel therapeutic strategies for dysfunctions of these processes, such as infertility and metabolic disorders.

  20. Doxorubicin in vivo rapidly alters expression and translation of myocardial electron transport chain genes, leads to ATP loss and caspase 3 activation.

    Directory of Open Access Journals (Sweden)

    Amy V Pointon

    Full Text Available BACKGROUND: Doxorubicin is one of the most effective anti-cancer drugs but its use is limited by cumulative cardiotoxicity that restricts lifetime dose. Redox damage is one of the most accepted mechanisms of toxicity, but not fully substantiated. Moreover doxorubicin is not an efficient redox cycling compound due to its low redox potential. Here we used genomic and chemical systems approaches in vivo to investigate the mechanisms of doxorubicin cardiotoxicity, and specifically test the hypothesis of redox cycling mediated cardiotoxicity. METHODOLOGY/PRINCIPAL FINDINGS: Mice were treated with an acute dose of either doxorubicin (DOX (15 mg/kg or 2,3-dimethoxy-1,4-naphthoquinone (DMNQ (25 mg/kg. DMNQ is a more efficient redox cycling agent than DOX but unlike DOX has limited ability to inhibit gene transcription and DNA replication. This allowed specific testing of the redox hypothesis for cardiotoxicity. An acute dose was used to avoid pathophysiological effects in the genomic analysis. However similar data were obtained with a chronic model, but are not specifically presented. All data are deposited in the Gene Expression Omnibus (GEO. Pathway and biochemical analysis of cardiac global gene transcription and mRNA translation data derived at time points from 5 min after an acute exposure in vivo showed a pronounced effect on electron transport chain activity. This led to loss of ATP, increased AMPK expression, mitochondrial genome amplification and activation of caspase 3. No data gathered with either compound indicated general redox damage, though site specific redox damage in mitochondria cannot be entirely discounted. CONCLUSIONS/SIGNIFICANCE: These data indicate the major mechanism of doxorubicin cardiotoxicity is via damage or inhibition of the electron transport chain and not general redox stress. There is a rapid response at transcriptional and translational level of many of the genes coding for proteins of the electron transport chain

  1. Alterações na dimensão transversal pela expansão rápida da maxila Transverse dimension alterations using rapid maxillary expansion

    Directory of Open Access Journals (Sweden)

    Roberto M. A. Lima Filho

    2009-10-01

    Full Text Available As deformidades transversais, que se manifestam tipicamente pela mordida cruzada unilateral ou bilateral, são os problemas esqueléticos que mais sequelas podem causar na região craniofacial. Entretanto, são as deformidades que melhor se adaptam às alterações ortopédicas. A expansão rápida da maxila tornou-se rotina na prática ortodôntica. Embora inicialmente tenha sido utilizada na correção da mordida cruzada posterior, atualmente sua indicação ampliou-se para a expansão indireta do arco inferior, obtenção de espaço para correção de apinhamento dentário, correção axial dos dentes posteriores, melhora na estética do sorriso e auxílio no tratamento de pacientes Classe II. A expansão ortopédica da maxila vem atraindo cada vez mais a atenção da comunidade científica devido, principalmente, à sua aplicação e capacidade de alterar o crescimento craniofacial em diversas situações clínicas. Esse tipo de intervenção ortopédica possui grande utilidade terapêutica, pois sua aplicação em diversas anormalidades apresenta maior versatilidade quando comparada aos aparelhos de modificação de crescimento disponíveis atualmente para o tratamento ortodôntico.Transverse deformities, typically manifested by unilateral or bilateral crossbite, are the skeletal problems that can cause more sequels in the craniofacial region. However, such deformities are the most adaptable to orthopedic changes. Rapid maxillary expansion has become a routine in the orthodontic practice. Even though initially such procedure has been used for correction of posterior crossbite, today it has been applied for indirect expansion of the lower arch, obtaining space for correction of dental crowding, correction of axial inclination of posterior teeth, improvement in the smile aesthetics characteristics and on treatment of Class II patients. Orthopedic maxillary expansion has gained increasing attention of the scientific community due to its

  2. Noisy Neurons

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 1. Noisy Neurons: Hodgkin-Huxley Model and Stochastic Variants. Shurti Paranjape. General Article Volume 20 Issue 1 January 2015 pp 34-43. Fulltext. Click here to view fulltext PDF. Permanent link:

  3. Anaesthesia generates neuronal insulin resistance by inducing hypothermia

    Directory of Open Access Journals (Sweden)

    Sutherland Calum

    2008-10-01

    Full Text Available Abstract Background Anaesthesia is commonly employed prior to surgical investigations and to permit icv injections in rodents. Indeed it is standard practise in many studies examining the subsequent actions of hormones and growth factors on the brain. Recent evidence that the basal activity of specific intracellular signalling proteins can be affected by anaesthesia prompted us to examine the effect of anaesthesia not only on the basal activity but also the insulin sensitivity of the major insulin signalling pathways. Results We find that urethane- and ketamine-induced anaesthesia results in rapid activation of the phosphatidylinositol (PI 3-kinase-protein kinase B (PKB signalling pathway in the brain, increases tau phosphorylation while at the same time reducing basal activity of the Ras-ERK pathway. Subsequent injection of insulin does not alter the activity of either the PI 3-kinase or ERK signalling pathways, indicating a degree of neuronal molecular insulin resistance. However, if body temperature is maintained during anaesthesia then there is no alteration in the basal activity of these signalling molecules. Subsequent response of both pathways to insulin injection is restored. Conclusion The data is consistent with a hypothermia related alteration in neuronal signalling following anaesthesia, and emphasises the importance of maintaining the body temperature of rodents when monitoring insulin (or growth factor/neurotrophic agent action in the brain of anesthetised rodents.

  4. Mutant copper-zinc superoxide dismutase (SOD1) induces protein secretion pathway alterations and exosome release in astrocytes: implications for disease spreading and motor neuron pathology in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Basso, Manuela; Pozzi, Silvia; Tortarolo, Massimo; Fiordaliso, Fabio; Bisighini, Cinzia; Pasetto, Laura; Spaltro, Gabriella; Lidonnici, Dario; Gensano, Francesco; Battaglia, Elisa; Bendotti, Caterina; Bonetto, Valentina

    2013-05-31

    Amyotrophic lateral sclerosis is the most common motor neuron disease and is still incurable. The mechanisms leading to the selective motor neuron vulnerability are still not known. The interplay between motor neurons and astrocytes is crucial in the outcome of the disease. We show that mutant copper-zinc superoxide dismutase (SOD1) overexpression in primary astrocyte cultures is associated with decreased levels of proteins involved in secretory pathways. This is linked to a general reduction of total secreted proteins, except for specific enrichment in a number of proteins in the media, such as mutant SOD1 and valosin-containing protein (VCP)/p97. Because there was also an increase in exosome release, we can deduce that astrocytes expressing mutant SOD1 activate unconventional secretory pathways, possibly as a protective mechanism. This may help limit the formation of intracellular aggregates and overcome mutant SOD1 toxicity. We also found that astrocyte-derived exosomes efficiently transfer mutant SOD1 to spinal neurons and induce selective motor neuron death. We conclude that the expression of mutant SOD1 has a substantial impact on astrocyte protein secretion pathways, contributing to motor neuron pathology and disease spread.

  5. Transient increase in neuronal chloride concentration by neuroactive amino acids released from glioma cells

    Directory of Open Access Journals (Sweden)

    Cristina eBertollini

    2012-11-01

    Full Text Available Neuronal chloride concentration ([Cl-]i is known to be dynamically modulated and alterations in Cl- homeostasis may occur in the brain at physiological and pathological conditions, being also likely involved in glioma-related seizures. However, the mechanism leading to changes in neuronal [Cl-]i during glioma invasion are still unclear. To characterize the potential effect of glioma released soluble factors on neuronal [Cl-]i, we used genetically encoded CFP/YFP-based ratiometric Cl-Sensor transiently expressed in cultured hippocampal neurons. Exposition of neurons to glioma conditioned medium (GCM caused rapid and transient elevation of [Cl-]i, resulting in the increase of fluorescence ratio, which was strongly reduced by blockers of ionotropic glutamate receptors APV and NBQX. Furthermore, in HEK cells expressing GluR1-AMPA receptors, GCM activated ionic current with efficacy similar to those caused by glutamate, supporting the notion that GCM contains glutamate or glutamatergic agonists, which cause neuronal depolarization, activation of NMDA and AMPA/KA receptors leading to elevation of [Cl-]i. Chromatographic analysis of the GCM showed that it contained several aminoacids, including glutamate, whose release from glioma cells did not occur via the most common glial mechanisms of transport, or in response to hypoosmotic stress. GCM also contained glycine, whose action contrasted the glutamate effect. Indeed, strychnine application significantly increased GCM-induced depolarization and [Cl-]i rise. GCM-evoked [Cl-]i elevation was not inhibited by antagonists of Cl- transporters and significantly reduced in the presence of anion channels blocker NPPB, suggesting that Cl-selective channels are a major route for GCM-induced Cl- influx. Altogether, these data show that glioma released aminoacids may dynamically alter Cl- equilibrium in surrounding neurons, deeply interfering with their inhibitory balance, likely leading to physiological and

  6. Increased transient Na+conductance and action potential output in layer 2/3 prefrontal cortex neurons of the fmr1-/ymouse.

    Science.gov (United States)

    Routh, Brandy N; Rathour, Rahul K; Baumgardner, Michael E; Kalmbach, Brian E; Johnston, Daniel; Brager, Darrin H

    2017-07-01

    Layer 2/3 neurons of the prefrontal cortex display higher gain of somatic excitability, responding with a higher number of action potentials for a given stimulus, in fmr1 -/y mice. In fmr1 -/y L2/3 neurons, action potentials are taller, faster and narrower. Outside-out patch clamp recordings revealed that the maximum Na + conductance density is higher in fmr1 -/y L2/3 neurons. Measurements of three biophysically distinct K + currents revealed a depolarizing shift in the activation of a rapidly inactivating (A-type) K + conductance. Realistic neuronal simulations of the biophysical observations recapitulated the elevated action potential and repetitive firing phenotype. Fragile X syndrome is the most common form of inherited mental impairment and autism. The prefrontal cortex is responsible for higher order cognitive processing, and prefrontal dysfunction is believed to underlie many of the cognitive and behavioural phenotypes associated with fragile X syndrome. We recently demonstrated that somatic and dendritic excitability of layer (L) 5 pyramidal neurons in the prefrontal cortex of the fmr1 -/y mouse is significantly altered due to changes in several voltage-gated ion channels. In addition to L5 pyramidal neurons, L2/3 pyramidal neurons play an important role in prefrontal circuitry, integrating inputs from both lower brain regions and the contralateral cortex. Using whole-cell current clamp recording, we found that L2/3 pyramidal neurons in prefrontal cortex of fmr1 -/y mouse fired more action potentials for a given stimulus compared with wild-type neurons. In addition, action potentials in fmr1 -/y neurons were significantly larger, faster and narrower. Voltage clamp of outside-out patches from L2/3 neurons revealed that the transient Na + current was significantly larger in fmr1 -/y neurons. Furthermore, the activation curve of somatic A-type K + current was depolarized. Realistic conductance-based simulations revealed that these biophysical changes in Na

  7. Acute melatonin treatment alters dendritic morphology and circadian clock gene expression in the hippocampus of Siberian hamsters.

    Science.gov (United States)

    Ikeno, Tomoko; Nelson, Randy J

    2015-02-01

    In the hippocampus of Siberian hamsters, dendritic length and dendritic complexity increase in the CA1 region whereas dendritic spine density decreases in the dentate gyrus region at night. However, the underlying mechanism of the diurnal rhythmicity in hippocampal neuronal remodeling is unknown. In mammals, most daily rhythms in physiology and behaviors are regulated by a network of circadian clocks. The central clock, located in the hypothalamus, controls melatonin secretion at night and melatonin modifies peripheral clocks by altering expression of circadian clock genes. In this study, we examined the effects of acute melatonin treatment on the circadian clock system as well as on morphological changes of hippocampal neurons. Male Siberian hamsters were injected with melatonin in the afternoon; 4 h later, mRNA levels of hypothalamic and hippocampal circadian clock genes and hippocampal neuron dendritic morphology were assessed. In the hypothalamus, melatonin treatment did not alter Period1 and Bmal1 expression. However, melatonin treatment increased both Period1 and Bmal1 expression in the hippocampus, suggesting that melatonin affected molecular oscillations in the hippocampus. Melatonin treatment also induced rapid remodeling of hippocampal neurons; melatonin increased apical dendritic length and dendritic complexity in the CA1 region and reduced the dendritic spine density in the dentate gyrus region. These data suggest that structural changes in hippocampal neurons are regulated by a circadian clock and that melatonin functions as a nighttime signal to coordinate the diurnal rhythm in neuronal remodeling. © 2014 Wiley Periodicals, Inc.

  8. Effects of a novel differentiation factor on the development of catecholamine traits in noncatecholamine neurons from various regions of the rat brain: studies in tissue culture.

    Science.gov (United States)

    Iacovitti, L

    1991-08-01

    The muscle-derived differentiation factor called MDF initiated expression of the catecholamine (CA) enzyme tyrosine hydroxylase (TH) in non-CA neurons isolated from a variety of regions in the rat brain. Specifically, subpopulations of neurons from the striatum, collicular plate, and cerebellum were TH-immunoreactive after an overnight exposure to MDF in culture. The number of immunopositive cells was greatest in the striatum, where more than half of all plated neurons expressed the enzyme. In contrast, MDF had no effect on the central neurons of the hippocampus or on peripheral sensory neurons. In 3H-thymidine studies, only brain neurons that had already withdrawn from mitosis expressed TH. These cells remained open to the epigenetic influence of MDF only during a brief and defined critical period that appears to be timed intrinsically. Without daily replenishment of MDF, expression of the enzyme disappeared after several days in culture, suggesting that MDF was rapidly depleted or degraded in vitro. However, in the continued presence of MDF, TH expression was maintained indefinitely, thus producing a permanent alteration in phenotype. Moreover, a single exposure to MDF during the critical period was sufficient to render neurons permanently receptive to the molecule so that TH expression could be reinitiated many days later. It is postulated that a memory of this biochemical interaction was established in these neurons, making transmitter phenotypic plasticity possible at later stages.

  9. Labeling of neuronal morphology using custom diolistic techniques.

    Science.gov (United States)

    Hough, Lyon H; Brown, Michael E

    2017-04-15

    Diolistic labeling is increasingly utilized in neuroscience as an efficient, reproducible method for visualization of neuronal morphology. The use of lipophilic carbocyanine dyes, combined with particle-mediated biolistic delivery allows for non-toxic fluorescent labeling of multiple neurons in both living and fixed tissue. Since first described, this labeling method has been modified to fit a variety of research goals and laboratory settings. Diolistic labeling has traditionally relied on commercially available devices for the propulsion of coated micro-particles into tissue sections. Recently, laboratory built biolistic devices have been developed which allow for increased availability and customization. Here, we discuss a custom biolistic device and provide a detailed protocol for its use. Using custom diolistic labeling we have characterized alterations in neuronal morphology of the lateral/dentate nucleus of the rat cerebellum. Comparisons were made in developing rat pups exposed to abnormally high levels of 5-methyloxytryptamine (5-MT) pre-and postnatally. Using quantitative software; dendritic morphology, architecture, and synaptic connections, were analyzed. The rapid nature of custom diolistics coupled with passive diffusion of dyes and compatibility with confocal microscopy, provides an unparalleled opportunity to examine features of neuronal cells at high spatial resolution in a three-dimensional tissue environment. While decreasing the associated costs, the laboratory-built device also overcomes many of the obstacles associated with traditional morphological labeling, to allow for reliable and reproducible neuronal labeling. The versatility of this method allows for its adaptation to a variety of laboratory settings and neuroscience related research goals. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Synaptic alterations in the medial geniculate bodies and the inferior colliculi in Alzheimer's disease: a Golgi and electron microscope study.

    Science.gov (United States)

    Baloyannis, Stavros J; Mauroudis, Ioannis; Manolides, Spyros L; Manolides, Leonidas S

    2009-04-01

    The neuronal loss and the alteration of the synapses in the medial geniculate bodies and the inferior colliculi may be involved in the impairment of communication and symbolic sound perception, which is noticed even in the early stages of Alzheimer's disease. Alzheimer's disease (AD) is a neurodegenerative disorder, causing a progressive decline of intellectual faculties, gradual impairment of behavior and social performance, impairment of communication and speech eloquence, and various neurological manifestations. We attempted to figure out the synaptic alterations in the medial geniculate bodies and the inferior colliculi in 12 early cases of Alzheimer's disease, who fulfilled the clinical, and laboratory diagnostic criteria of Alzheimer's disease. For the histological study we applied routine neuropathological techniques as well as Bodian staining and rapid Golgi method. We proceeded to electron microscopy for the ultrastructural study of synapses and dendritic spines. The morphological and morphometric analysis revealed substantial neuronal loss and synaptic alterations in the medial geniculate bodies as well as in inferior colliculi. Dendritic spines of the polyhedral and elongated cells of the medial geniculate bodies were decreased in number. Mitochondrial alterations and fragmentation of Golgi apparatus were seen in 15% of the neurons of the medial geniculate bodies and in 5% of the neurons of the inferior colliculi. Senile plaques and neurofibrillary tangles were not seen in either the medial geniculate bodies or the inferior colliculi.

  11. Characterisation of early mucosal and neuronal lesions following Shigella flexneri infection in human colon.

    Directory of Open Access Journals (Sweden)

    Emmanuel Coron

    Full Text Available BACKGROUND: Shigella, an enteroinvasive bacteria induces a major inflammatory response responsible for acute rectocolitis in humans. However, early effect of Shigella flexneri (S. flexneri infection upon the human mucosa and its microenvironement, in particular the enteric nervous system, remains currently unknown. Therefore, in this study, we sought to characterize ex vivo the early events of shigellosis in a model of human colonic explants. In particular, we aimed at identifying factors produced by S. flexneri and responsible for the lesions of the barrier. We also aimed at determining the putative lesions of the enteric nervous system induced by S. flexneri. METHODOLOGY/PRINCIPAL FINDINGS: We first showed that, following 3 h of infection, the invasive but not the non-invasive strain of S. flexneri induced significant desquamation of the intestinal epithelial barrier and a reduction of epithelial height. These changes were significantly reduced following infection with SepA deficient S. flexneri strains. Secondly, S. flexneri induced rapid neuronal morphological alterations suggestive of cell death in enteric submucosal neurones. These alterations were associated with a significant increase in the proportion of vasoactive intestinal peptide (VIP immunoreactive (IR neurons but not in total VIP levels. The NMDA receptor antagonist MK-801 blocked neuronal morphological changes induced by S. flexneri, but not the increase in the proportion of VIP-IR. CONCLUSIONS/SIGNIFICANCE: This human explant model can be used to gain better insight into the early pathogenic events following S. flexneri infection and the mechanisms involved.

  12. A Case for Microtubule Vulnerability in Amyotrophic Lateral Sclerosis: Altered Dynamics During Disease

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    Jayden A Clark

    2016-09-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is an aggressive multifactorial disease converging on a common pathology: the degeneration of motor neurons, their axons and neuromuscular synapses. This vulnerability and dysfunction of motor neurons highlights the dependency of these large cells on their intracellular machinery. Neuronal microtubules are an intracellular structure that facilitates a myriad of vital neuronal functions, including activity dependent axonal transport. In ALS it is becoming increasingly apparent that microtubules are likely to be a critical component of this disease. Not only are disruptions in this intracellular machinery present in the vast majority of seemingly sporadic cases, recent research has revealed that mutation to a microtubule protein, the tubulin isoform TUBA4A, is sufficient to cause a familial, albeit rare, form of disease. In both sporadic and familial disease, studies have provided evidence that microtubule mediated deficits in axonal transport are the tipping point for motor neuron survivability. Axonal transport deficits would lead to abnormal mitochondrial recycling, decreased vesicle and mRNA transport and limited signalling of key survival factors from the neurons peripheral synapses, causing the characteristic peripheral ‘die back’. This disruption to microtubule dependant transport in ALS has been shown to result from alterations in the phenomenon of microtubule dynamic instability: the rapid growth and shrinkage of microtubule polymers. This is accomplished primarily due to aberrant alterations to microtubule associated proteins (MAPS that regulate microtubule stability. Indeed, the current literature would argue that microtubule stability, particularly alterations in their dynamics, may be the initial driving force behind many familial and sporadic insults in ALS. Pharmacological stabilisation of the microtubule network offers an attractive therapeutic strategy in ALS; indeed it has shown promise in

  13. Postnatal neurogenesis: from neuroblast migration to neuronal integration.

    Science.gov (United States)

    Belvindrah, Richard; Lazarini, Françoise; Lledo, Pierre-Marie

    2009-01-01

    Ongoing neurogenesis maintains neuronal replacement in a few regions of the mammalian adult brain. One of these regions, the subventricular zone, generates olfactory bulb interneuron precursors that must migrate through the rostral migratory stream to reach the olfactory bulb circuit. There, they rapidly initiate dendritic growth and establish dendro-dendritic contacts with mitral/tufted cells and potentially other local interneurons. The sequential steps involved in neuroblast maturation during development have been studied extensively over previous years. However, the mechanisms and regulatory factors controlling the recruitment and first steps of synaptic integration of newly-formed neurons in the adult forebrain have only recently started to be elucidated. This review provides an integrated view of our current understanding of fate-choice decision in progenitors, how newborn neurons correctly migrate to specific circuits, how they integrate in olfactory bulb microcircuits, and the function they have to fulfill once they survive. The elucidation of these mechanisms may be crucial to understand the functional role of adult neurogenesis and eventually develop therapeutic strategies aimed at re-routing neuroblasts to altered circuits.

  14. Estrogen receptor–α in medial amygdala neurons regulates body weight

    Science.gov (United States)

    Xu, Pingwen; Cao, Xuehong; He, Yanlin; Zhu, Liangru; Yang, Yongjie; Saito, Kenji; Wang, Chunmei; Yan, Xiaofeng; Hinton, Antentor Othrell; Zou, Fang; Ding, Hongfang; Xia, Yan; Yan, Chunling; Shu, Gang; Wu, San-Pin; Yang, Bin; Feng, Yuxin; Clegg, Deborah J.; DeMarchi, Richard; Khan, Sohaib A.; Tsai, Sophia Y.; DeMayo, Francesco J.; Wu, Qi; Tong, Qingchun; Xu, Yong

    2015-01-01

    Estrogen receptor–α (ERα) activity in the brain prevents obesity in both males and females. However, the ERα-expressing neural populations that regulate body weight remain to be fully elucidated. Here we showed that single-minded–1 (SIM1) neurons in the medial amygdala (MeA) express abundant levels of ERα. Specific deletion of the gene encoding ERα (Esr1) from SIM1 neurons, which are mostly within the MeA, caused hypoactivity and obesity in both male and female mice fed with regular chow, increased susceptibility to diet-induced obesity (DIO) in males but not in females, and blunted the body weight–lowering effects of a glucagon-like peptide-1–estrogen (GLP-1–estrogen) conjugate. Furthermore, selective adeno-associated virus-mediated deletion of Esr1 in the MeA of adult male mice produced a rapid body weight gain that was associated with remarkable reductions in physical activity but did not alter food intake. Conversely, overexpression of ERα in the MeA markedly reduced the severity of DIO in male mice. Finally, an ERα agonist depolarized MeA SIM1 neurons and increased their firing rate, and designer receptors exclusively activated by designer drug–mediated (DREADD-mediated) activation of these neurons increased physical activity in mice. Collectively, our results support a model where ERα signals activate MeA neurons to stimulate physical activity, which in turn prevents body weight gain. PMID:26098212

  15. Serum Response Factor (SRF mediated gene activity in physiological and pathological processes of neuronal motility

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    Bernd eKnoll

    2011-12-01

    Full Text Available In recent years, the transcription factor SRF (serum response factor was shown to contribute to various physiological processes linked to neuronal motility. The latter include cell migration, axon guidance and e.g. synapse function relying on cytoskeletal dynamics, neurite outgrowth, axonal and dendritic differentiation, growth cone motility and neurite branching. SRF teams up with MRTFs (myocardin related transcription factors and TCFs (ternary complex factors to mediate cellular actin cytoskeletal dynamics and the immediate-early gene (IEG response, a bona fide indicator of neuronal activation. Herein, I will discuss how SRF and cofactors might modulate physiological processes of neuronal motility. Further, potential mechanisms engaged by neurite growth promoting molecules and axon guidance cues to target SRF’s transcriptional machinery in physiological neuronal motility will be presented. Of note, altered cytoskeletal dynamics and rapid initiation of an IEG response are a hallmark of injured neurons in various neurological disorders. Thus, SRF and its MRTF and TCF cofactors might emerge as a novel trio modulating peripheral and central axon regeneration.

  16. Reactive biomolecular divergence in genetically altered yeast cells and isolated mitochondria as measured by biocavity laser spectroscopy : a rapid diagnostic method for studying cellular responses to stress and disease.

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    Yaffe, Michael P. (University of California, San Diego, CA); Gourley, Paul Lee; Copeland, Robert Guild; McDonald, Anthony Eugene; Hendricks, Judy K.; Naviaux, Robert K. (Univesity of California, San Diego, CA)

    2006-12-01

    We report an analysis of four strains of baker's yeast (Saccharomyces cerevisiae) using biocavity laser spectroscopy. The four strains are grouped in two pairs (wild type and altered), in which one strain differs genetically at a single locus, affecting mitochondrial function. In one pair, the wild-type rho+ and a rho0 strain differ by complete removal of mitochondrial DNA (mtDNA). In the second pair, the wild-type rho+ and a rho- strain differ by knock-out of the nuclear gene encoding Cox4, an essential subunit of cytochrome c oxidase. The biocavity laser is used to measure the biophysical optic parameter Deltalambda, a laser wavelength shift relating to the optical density of cell or mitochondria that uniquely reflects its size and biomolecular composition. As such, Deltalambda is a powerful parameter that rapidly interrogates the biomolecular state of single cells and mitochondria. Wild-type cells and mitochondria produce Gaussian-like distributions with a single peak. In contrast, mutant cells and mitochondria produce leptokurtotic distributions that are asymmetric and highly skewed to the right. These distribution changes could be self-consistently modeled with a single, log-normal distribution undergoing a thousand-fold increase in variance of biomolecular composition. These features reflect a new state of stressed or diseased cells that we call a reactive biomolecular divergence (RBD) that reflects the vital interdependence of mitochondria and the nucleus.

  17. Shaping Neuronal Network Activity by Presynaptic Mechanisms.

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    Ayal Lavi

    2015-09-01

    Full Text Available Neuronal microcircuits generate oscillatory activity, which has been linked to basic functions such as sleep, learning and sensorimotor gating. Although synaptic release processes are well known for their ability to shape the interaction between neurons in microcircuits, most computational models do not simulate the synaptic transmission process directly and hence cannot explain how changes in synaptic parameters alter neuronal network activity. In this paper, we present a novel neuronal network model that incorporates presynaptic release mechanisms, such as vesicle pool dynamics and calcium-dependent release probability, to model the spontaneous activity of neuronal networks. The model, which is based on modified leaky integrate-and-fire neurons, generates spontaneous network activity patterns, which are similar to experimental data and robust under changes in the model's primary gain parameters such as excitatory postsynaptic potential and connectivity ratio. Furthermore, it reliably recreates experimental findings and provides mechanistic explanations for data obtained from microelectrode array recordings, such as network burst termination and the effects of pharmacological and genetic manipulations. The model demonstrates how elevated asynchronous release, but not spontaneous release, synchronizes neuronal network activity and reveals that asynchronous release enhances utilization of the recycling vesicle pool to induce the network effect. The model further predicts a positive correlation between vesicle priming at the single-neuron level and burst frequency at the network level; this prediction is supported by experimental findings. Thus, the model is utilized to reveal how synaptic release processes at the neuronal level govern activity patterns and synchronization at the network level.

  18. Shaping Neuronal Network Activity by Presynaptic Mechanisms

    Science.gov (United States)

    Ashery, Uri

    2015-01-01

    Neuronal microcircuits generate oscillatory activity, which has been linked to basic functions such as sleep, learning and sensorimotor gating. Although synaptic release processes are well known for their ability to shape the interaction between neurons in microcircuits, most computational models do not simulate the synaptic transmission process directly and hence cannot explain how changes in synaptic parameters alter neuronal network activity. In this paper, we present a novel neuronal network model that incorporates presynaptic release mechanisms, such as vesicle pool dynamics and calcium-dependent release probability, to model the spontaneous activity of neuronal networks. The model, which is based on modified leaky integrate-and-fire neurons, generates spontaneous network activity patterns, which are similar to experimental data and robust under changes in the model's primary gain parameters such as excitatory postsynaptic potential and connectivity ratio. Furthermore, it reliably recreates experimental findings and provides mechanistic explanations for data obtained from microelectrode array recordings, such as network burst termination and the effects of pharmacological and genetic manipulations. The model demonstrates how elevated asynchronous release, but not spontaneous release, synchronizes neuronal network activity and reveals that asynchronous release enhances utilization of the recycling vesicle pool to induce the network effect. The model further predicts a positive correlation between vesicle priming at the single-neuron level and burst frequency at the network level; this prediction is supported by experimental findings. Thus, the model is utilized to reveal how synaptic release processes at the neuronal level govern activity patterns and synchronization at the network level. PMID:26372048

  19. Dietary plant lectins appear to be transported from the gut to gain access to and alter dopaminergic neurons of Caenorhabditis elegans, a potential etiology of Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Jolene eZheng

    2016-03-01

    Full Text Available Lectins from dietary plants have been shown to enhance drug absorption in the gastrointestinal tract of rats, be transported trans-synaptically as shown by tracing of axonal and dendritic paths, and enhance gene delivery. Other carbohydrate-binding protein toxins are known to traverse the gut intact in dogs. Post-feeding rhodamine- or TRITC-tagged dietary lectins, the lectins were tracked from gut to dopaminergic neurons (DAergic-N in transgenic Caenorhabditis elegans (C. elegans (egIs1[Pdat-1::GFP] where the mutant has the Green Fluorescent Protein (GFP gene fused to a dopamine transport protein gene labeling dopaminergic neurons, The lectins were supplemented along with the food organism Escherichia coli (OP50. Among nine tested rhodamine/TRITC-tagged lectins, four, including Phaseolus vulgaris erythroagglutinin (PHA-E, Bandeiraea simplicifolia (BS-I, Dolichos biflorus agglutinin (DBA, and Arachis hypogaea (PNA, appeared to be transported from gut to the GFP-DAergic-N. Griffonia Simplicifolia (GSL-I and PHA-E, reduced the number of GFP-DAergic-N suggesting a toxic activity. PHA-E, BS-I, Pisum Sativum (PSA, and Triticum vulgaris agglutinin (Succinylated reduced fluorescent intensity of GFP-DAergic-N. PHA-E, PSA, Concanavalin A, and Triticum vulgaris agglutinin decreased the size of GFP-DAergic-N, while BS-I increased neuron size. These observations suggest that dietary plant lectins are transported to and affect DAergic-N in C. elegans, which support Braak and Hawkes’ hypothesis, suggesting one alternate potential dietary etiology of Parkinson’s disease (PD. A recent Danish study showed that vagotomy resulted in 40% lower incidence of PD over 20 years. Differences in inherited sugar structures of gut and neuronal cell surfaces may make some individuals more susceptible in this conceptual disease etiology model.

  20. TASK Channels on Basal Forebrain Cholinergic Neurons Modulate Electrocortical Signatures of Arousal by Histamine

    Science.gov (United States)

    Vu, Michael T.; Du, Guizhi; Bayliss, Douglas A.

    2015-01-01

    Basal forebrain cholinergic neurons are the main source of cortical acetylcholine, and their activation by histamine elicits cortical arousal. TWIK-like acid-sensitive K+ (TASK) channels modulate neuronal excitability and are expressed on basal forebrain cholinergic neurons, but the role of TASK channels in the histamine-basal forebrain cholinergic arousal circuit is unknown. We first expressed TASK channel subunits and histamine Type 1 receptors in HEK cells. Application of histamine in vitro inhibited the acid-sensitive K+ current, indicating a functionally coupled signaling mechanism. We then studied the role of TASK channels in modulating electrocortical activity in vivo using freely behaving wild-type (n = 12) and ChAT-Cre:TASKf/f mice (n = 12), the latter lacking TASK-1/3 channels on cholinergic neurons. TASK channel deletion on cholinergic neurons significantly altered endogenous electroencephalogram oscillations in multiple frequency bands. We then identified the effect of TASK channel deletion during microperfusion of histamine into the basal forebrain. In non-rapid eye movement sleep, TASK channel deletion on cholinergic neurons significantly attenuated the histamine-induced increase in 30–50 Hz activity, consistent with TASK channels contributing to histamine action on basal forebrain cholinergic neurons. In contrast, during active wakefulness, histamine significantly increased 30–50 Hz activity in ChAT-Cre:TASKf/f mice but not wild-type mice, showing that the histamine response depended upon the prevailing cortical arousal state. In summary, we identify TASK channel modulation in response to histamine receptor activation in vitro, as well as a role of TASK channels on cholinergic neurons in modulating endogenous oscillations in the electroencephalogram and the electrocortical response to histamine at the basal forebrain in vivo. SIGNIFICANCE STATEMENT Attentive states and cognitive function are associated with the generation of γ EEG activity

  1. Sensory neuron-derived eph regulates glomerular arbors and modulatory function of a central serotonergic neuron.

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    Ajeet Pratap Singh

    2013-04-01

    Full Text Available Olfactory sensory neurons connect to the antennal lobe of the fly to create the primary units for processing odor cues, the glomeruli. Unique amongst antennal-lobe neurons is an identified wide-field serotonergic neuron, the contralaterally-projecting, serotonin-immunoreactive deutocerebral neuron (CSDn. The CSDn spreads its termini all over the contralateral antennal lobe, suggesting a diffuse neuromodulatory role. A closer examination, however, reveals a restricted pattern of the CSDn arborization in some glomeruli. We show that sensory neuron-derived Eph interacts with Ephrin in the CSDn, to regulate these arborizations. Behavioural analysis of animals with altered Eph-ephrin signaling and with consequent arborization defects suggests that neuromodulation requires local glomerular-specific patterning of the CSDn termini. Our results show the importance of developmental regulation of terminal arborization of even the diffuse modulatory neurons to allow them to route sensory-inputs according to the behavioural contexts.

  2. Synchronization properties of heterogeneous neuronal networks with mixed excitability type.

    Science.gov (United States)

    Leone, Michael J; Schurter, Brandon N; Letson, Benjamin; Booth, Victoria; Zochowski, Michal; Fink, Christian G

    2015-03-01

    We study the synchronization of neuronal networks with dynamical heterogeneity, showing that network structures with the same propensity for synchronization (as quantified by master stability function analysis) may develop dramatically different synchronization properties when heterogeneity is introduced with respect to neuronal excitability type. Specifically, we investigate networks composed of neurons with different types of phase response curves (PRCs), which characterize how oscillating neurons respond to excitatory perturbations. Neurons exhibiting type 1 PRC respond exclusively with phase advances, while neurons exhibiting type 2 PRC respond with either phase delays or phase advances, depending on when the perturbation occurs. We find that Watts-Strogatz small world networks transition to synchronization gradually as the proportion of type 2 neurons increases, whereas scale-free networks may transition gradually or rapidly, depending upon local correlations between node degree and excitability type. Random placement of type 2 neurons results in gradual transition to synchronization, whereas placement of type 2 neurons as hubs leads to a much more rapid transition, showing that type 2 hub cells easily "hijack" neuronal networks to synchronization. These results underscore the fact that the degree of synchronization observed in neuronal networks is determined by a complex interplay between network structure and the dynamical properties of individual neurons, indicating that efforts to recover structural connectivity from dynamical correlations must in general take both factors into account.

  3. Dietary Plant Lectins Appear to Be Transported from the Gut to Gain Access to and Alter Dopaminergic Neurons of Caenorhabditis elegans, a Potential Etiology of Parkinson’s Disease

    Science.gov (United States)

    Zheng, Jolene; Wang, Mingming; Wei, Wenqian; Keller, Jeffrey N.; Adhikari, Binita; King, Jason F.; King, Michael L.; Peng, Nan; Laine, Roger A.

    2016-01-01

    Lectins from dietary plants have been shown to enhance drug absorption in the gastrointestinal tract of rats, be transported trans-synaptically as shown by tracing of axonal and dendritic paths, and enhance gene delivery. Other carbohydrate-binding protein toxins are known to traverse the gut intact in dogs. Post-feeding rhodamine- or TRITC-tagged dietary lectins, the lectins were tracked from gut to dopaminergic neurons (DAergic-N) in transgenic Caenorhabditis elegans (C. elegans) [egIs1(Pdat-1:GFP)] where the mutant has the green fluorescent protein (GFP) gene fused to a dopamine transport protein gene labeling DAergic-N. The lectins were supplemented along with the food organism Escherichia coli (OP50). Among nine tested rhodamine/TRITC-tagged lectins, four, including Phaseolus vulgaris erythroagglutinin (PHA-E), Bandeiraea simplicifolia (BS-I), Dolichos biflorus agglutinin (DBA), and Arachis hypogaea agglutinin (PNA), appeared to be transported from gut to the GFP-DAergic-N. Griffonia Simplicifolia and PHA-E, reduced the number of GFP-DAergic-N, suggesting a toxic activity. PHA-E, BS-I, Pisum sativum (PSA), and Triticum vulgaris agglutinin (Succinylated) reduced fluorescent intensity of GFP-DAergic-N. PHA-E, PSA, Concanavalin A, and Triticum vulgaris agglutinin decreased the size of GFP-DAergic-N, while BS-I increased neuron size. These observations suggest that dietary plant lectins are transported to and affect DAergic-N in C. elegans, which support Braak and Hawkes’ hypothesis, suggesting one alternate potential dietary etiology of Parkinson’s disease (PD). A recent Danish study showed that vagotomy resulted in 40% lower incidence of PD over 20 years. Differences in inherited sugar structures of gut and neuronal cell surfaces may make some individuals more susceptible in this conceptual disease etiology model. PMID:27014695

  4. Quantitative glycomics monitoring of induced pluripotent- and embryonic stem cells during neuronal differentiation

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    Michiyo Terashima

    2014-11-01

    Full Text Available Alterations in the structure of cell surface glycoforms occurring during the stages of stem cell differentiation remain unclear. We describe a rapid glycoblotting-based cellular glycomics method for quantitatively evaluating changes in glycoform expression and structure during neuronal differentiation of murine induced pluripotent stem cells (iPSCs and embryonic stem cells (ESCs. Our results show that changes in the expression of cellular N-glycans are comparable during the differentiation of iPSCs and ESCs. The expression of bisect-type N-glycans was significantly up-regulated in neurons that differentiated from both iPSCs and ESCs. From a glycobiological standpoint, iPSCs are an alternative neural cell source in addition to ESCs.

  5. Ephaptic coupling in cortical neurons

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    Costas Anastassiou

    2014-03-01

    Full Text Available The electrochemical processes that underlie neural function manifest themselves in ceaseless spatial and temporal fluctuations in the extracellular electric field. The local field potential (LFP, used to study neural interactions during various brain states, is regarded as an epiphenomenon of coordinated neural activity. Yet the extracellular field activity feeds back onto the electrical potential across the neuronal membrane via ephaptic coupling (Jefferys et al, Physiol Rev, 1995. The extent to which such ephaptic coupling alters the functioning of individual neurons and neural assemblies under physiological conditions has remained largely speculative despite recent advances (Ozen et al, JNeurosci, 2010; Fröhlich & McCormick, Neuron, 2010, Anastassiou et al, JNeurosci, 2010. To address this question we use a 12-pipette setup that allows independent positioning of each pipette under visual control with μm accuracy, with the flexibility of using an arbitrary number of these as patching, extracellularly stimulating or extracellular recording pipettes only a few μm away from the cell body of patched neurons (Anastassiou et al, Nat Neurosci, 2011. We stimulated in rat somatosensory cortical slices a variety of layer 5 neural types and recorded inside and outside their cell bodies while pharmacologically silencing synaptic transmission. Pyramidal cells couple to the extracellular field distinctly different from interneurons. Ephaptic coupling strength depends both on the field strength (as measured at the neuron soma as well as the spike-history of neurons. In particular, we find that ephaptic coupling strength depends both on the field strength (as measured at the cell body as well as the spike-history of neurons. How do such effects manifest themselves in vivo? We address this question through detailed large-scale simulations from thousands of biophysically realistic and interconnected neurons (Reimann, Anastassiou et al, Neuron, 2013 emulating

  6. GABA FUNCTION IS ALTERED FOLLOWING DEVELOPMENTAL HYPOTHYROIDISM: NEUROANATOMICAL AND NEUROPHYSIOLOGICAL EVIDENCE.

    Science.gov (United States)

    Thyroid hormone deficiency during development produces changes in the structure of neurons and glial cells and alters synaptic function in the hippocampus. GABAergic interneurons comprise the bulk of local inhibitory neuronal circuitry and a subpopulation of these interneurons ...

  7. Use of Genetically Altered Stem Cells for the Treatment of Huntington’s Disease

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    Andrew T. Crane

    2014-03-01

    Full Text Available Transplantation of stem cells for the treatment of Huntington’s disease (HD garnered much attention prior to the turn of the century. Several studies using mesenchymal stem cells (MSCs have indicated that these cells have enormous therapeutic potential in HD and other disorders. Advantages of using MSCs for cell therapies include their ease of isolation, rapid propagation in culture, and favorable immunomodulatory profiles. However, the lack of consistent neuronal differentiation of transplanted MSCs has limited their therapeutic efficacy to slowing the progression of HD-like symptoms in animal models of HD. The use of MSCs which have been genetically altered to overexpress brain derived neurotrophic factor to enhance support of surviving cells in a rodent model of HD provides proof-of-principle that these cells may provide such prophylactic benefits. New techniques that may prove useful for cell replacement therapies in HD include the use of genetically altering fate-restricted cells to produce induced pluripotent stem cells (iPSCs. These iPSCs appear to have certain advantages over the use of embryonic stem cells, including being readily available, easy to obtain, less evidence of tumor formation, and a reduced immune response following their transplantation. Recently, transplants of iPSCs have shown to differentiate into region-specific neurons in an animal model of HD. The overall successes of using genetically altered stem cells for reducing neuropathological and behavioral deficits in rodent models of HD suggest that these approaches have considerable potential for clinical use. However, the choice of what type of genetically altered stem cell to use for transplantation is dependent on the stage of HD and whether the end-goal is preserving endogenous neurons in early-stage HD, or replacing the lost neurons in late-stage HD. This review will discuss the current state of stem cell technology for treating the different stages of HD and

  8. TETRAMETHRIN AND DDT INHIBIT SPONTANEOUS FIRING IN CORTICAL NEURONAL NETWORKS

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    The insecticidal and neurotoxic effects of pyrethroids result from prolonged sodium channel inactivation, which causes alterations in neuronal firing and communication. Previously, we determined the relative potencies of 11 type I and type II pyrethroid insecticides using microel...

  9. Computational Modeling of Neuronal Current MRI Signals with Rat Somatosensory Cortical Neurons.

    Science.gov (United States)

    BagheriMofidi, Seyed Mehdi; Pouladian, Majid; Jameie, Seyed Behnammodin; Abbaspour Tehrani-Fard, Ali

    2016-09-01

    Magnetic field generated by active neurons has recently been considered to determine location of neuronal activity directly with magnetic resonance imaging (MRI), but controversial results have been reported about detection of such small magnetic fields. In this study, multiple neuronal morphologies of rat tissue were modeled to investigate better estimation of MRI signal change produced by neuronal magnetic field (NMF). Ten pyramidal neurons from layer II to VI of rat somatosensory area with realistic morphology, biophysics, and neuronal density were modeled to simulate NMF of neuronal tissue, from which effects of NMF on MRI signals were obtained. Neuronal current MRI signals, which consist of relative magnitude signal change (RMSC) and phase signal change (PSC), were at least three and one orders of magnitude less than a tissue with single neuron type, respectively. Also, a reduction in voxel size could increase signal alterations. Furthermore, with selection of zenith angle of external main magnetic field related to tissue surface near to 90°, RMSC could be maximized. This value for PSC would be 90° for small voxel size and zero degree for large ones.

  10. Neuronal encoding of the switch from specific to generalized fear.

    Science.gov (United States)

    Ghosh, Supriya; Chattarji, Sumantra

    2015-01-01

    Fear memories are crucial for survival. However, excessive generalization of such memories, characterized by a failure to discriminate dangerous from safe stimuli, is common in anxiety disorders. Neuronal encoding of the transition from cue-specific to generalized fear is poorly understood. We identified distinct neuronal populations in the lateral amygdala (LA) of rats that signaled generalized versus cue-specific associations and determined how their distributions switched during fear generalization. Notably, the same LA neurons that were cue specific before the behavioral shift to generalized fear lost their specificity afterwards, thereby tilting the balance of activity toward a greater proportion of generalizing neurons. Neuronal activity in the LA, but not the auditory cortex, was necessary for fear generalization. Furthermore, targeted activation of cAMP-PKA signaling in the LA increased neuronal excitability of LA neurons and led to generalized fear. These results provide a cellular basis in the amygdala for the alteration of emotional states from normal to pathological fear.

  11. Closed-Loop Characterization of Neuronal Activation Using Electrical Stimulation and Optical Imaging

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    Michelle L. Kuykendal

    2017-06-01

    Full Text Available We have developed a closed-loop, high-throughput system that applies electrical stimulation and optical recording to facilitate the rapid characterization of extracellular, stimulus-evoked neuronal activity. In our system, a microelectrode array delivers current pulses to a dissociated neuronal culture treated with a calcium-sensitive fluorescent dye; automated real-time image processing of high-speed digital video identifies the neuronal response; and an optimized search routine alters the applied stimulus to achieve a targeted response. Action potentials are detected by measuring the post-stimulus, calcium-sensitive fluorescence at the neuronal somata. The system controller performs directed searches within the strength–duration (SD stimulus-parameter space to build probabilistic neuronal activation curves. This closed-loop system reduces the number of stimuli needed to estimate the activation curves when compared to the more commonly used open-loop approach. This reduction allows the closed-loop system to probe the stimulus regions of interest in the multi-parameter waveform space with increased resolution. A sigmoid model was fit to the stimulus-evoked activation data in both current (strength and pulse width (duration parameter slices through the waveform space. The two-dimensional analysis results in a set of probability isoclines corresponding to each neuron–electrode pair. An SD threshold model was then fit to the isocline data. We demonstrate that a closed-loop methodology applied to our imaging and micro-stimulation system enables the study of neuronal excitation across a large parameter space.

  12. Frizzled-5 receptor is involved in neuronal polarity and morphogenesis of hippocampal neurons.

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    Paula G Slater

    Full Text Available The Wnt signaling pathway plays important roles during different stages of neuronal development, including neuronal polarization and dendritic and axonal outgrowth. However, little is known about the identity of the Frizzled receptors mediating these processes. In the present study, we investigated the role of Frizzled-5 (Fzd5 on neuronal development in cultured Sprague-Dawley rat hippocampal neurons. We found that Fzd5 is expressed early in cultured neurons on actin-rich structures localized at minor neurites and axonal growth cones. At 4 DIV, Fzd5 polarizes towards the axon, where its expression is detected mainly at the peripheral zone of axonal growth cones, with no obvious staining at dendrites; suggesting a role of Fzd5 in neuronal polarization. Overexpression of Fzd5 during the acquisition of neuronal polarity induces mislocalization of the receptor and a loss of polarized axonal markers. Fzd5 knock-down leads to loss of axonal proteins, suggesting an impaired neuronal polarity. In contrast, overexpression of Fzd5 in neurons that are already polarized did not alter polarity, but decreased the total length of axons and increased total dendrite length and arborization. Fzd5 activated JNK in HEK293 cells and the effects triggered by Fzd5 overexpression in neurons were partially prevented by inhibition of JNK, suggesting that a non-canonical Wnt signaling mechanism might be involved. Our results suggest that, Fzd5 has a role in the establishment of neuronal polarity, and in the morphogenesis of neuronal processes, in part through the activation of the non-canonical Wnt mechanism involving JNK.

  13. Rapid Analytical Methods for On-Site Triage for Traumatic Brain Injury

    Science.gov (United States)

    North, Stella H.; Shriver-Lake, Lisa C.; Taitt, Chris R.; Ligler, Frances S.

    2012-07-01

    Traumatic brain injury (TBI) results from an event that causes rapid acceleration and deceleration of the brain or penetration of the skull with an object. Responses to stimuli and questions, loss of consciousness, and altered behavior are symptoms currently used to justify brain imaging for diagnosis and therapeutic guidance. Tests based on such symptoms are susceptible to false-positive and false-negative results due to stress, fatigue, and medications. Biochemical markers of neuronal damage and the physiological response to that damage are being identified. Biosensors capable of rapid measurement of such markers in the circulation offer a solution for on-site triage, as long as three criteria are met: (a) Recognition reagents can be identified that are sufficiently sensitive and specific, (b) the biosensor can provide quantitative assessment of multiple markers rapidly and simultaneously, and (c) both the sensor and reagents are designed for use outside the laboratory.

  14. Norepinephrine metabolism in neuronal cultures is increased by angiotensin II

    Energy Technology Data Exchange (ETDEWEB)

    Sumners, C.; Shalit, S.L.; Kalberg, C.J.; Raizada, M.K.

    1987-06-01

    In this study the authors have examined the actions of angiotensin II (ANG II) on catecholamine metabolism in neuronal brain cell cultures prepared from the hypothalamus and brain stem. Neuronal cultures prepared from the brains of 1-day-old Sprague-Dawley rats exhibit specific neuronal uptake mechanisms for both norepinephrine (NE) and dopamine (DA), and also monoamine oxidase (MAO) and catechol O-methyltransferase (COMT) activity. Separate neuronal uptake sites for NE and DA were identified by using specific neuronal uptake inhibitors for each amine. In previous studies, they determined that ANG II (10 nM-1 ..mu..M) stimulates increased neuronal (/sup 3/H)NE uptake by acting as specific receptors. They have confirmed these results here and in addition have shown that ANG II has not significant effects on neuronal (/sup 3/H)DA uptake. These results suggest that the actions of ANG II are restricted to the NE transporter in neuronal cultures. It is possible that ANG II stimulates the intraneuronal metabolism of at least part of the NE that is taken up, because the peptide stimulates MAO activity, an effect mediated by specific ANG II receptors. ANG II had no effect on COMT activity in neuronal cultures. Therefore, the use of neuronal cultures of hypothalamus and brain stem they have determined that ANG II can specifically alter NE metabolism in these areas, while apparently not altering DA metabolism.

  15. Sigma-1 Receptor and Neuronal Excitability.

    Science.gov (United States)

    Kourrich, Saïd

    2017-01-01

    The sigma-1 receptor (Sig-1R), via interaction with various proteins, including voltage-gated and ligand-gated ion channels (VGICs and LGICs), is involved in a plethora of neuronal functions. This capability to regulate a variety of ion channel targets endows the Sig-1R with a powerful capability to fine tune neuronal excitability, and thereby the transmission of information within brain circuits. This versatility may also explain why the Sig-1R is associated to numerous diseases at both peripheral and central levels. To date, how the Sig-1R chooses its targets and how the combinations of target modulations alter overall neuronal excitability is one of the challenges in the field of Sig-1R-dependent regulation of neuronal activity. Here, we will describe and discuss the latest findings on Sig-1R-dependent modulation of VGICs and LGICs, and provide hypotheses that may explain the diverse excitability outcomes that have been reported so far.

  16. A-type K+ channels encoded by Kv4.2, Kv4.3 and Kv1.4 differentially regulate intrinsic excitability of cortical pyramidal neurons

    Science.gov (United States)

    Carrasquillo, Yarimar; Burkhalter, Andreas; Nerbonne, Jeanne M

    2012-01-01

    Rapidly activating and rapidly inactivating voltage-gated A-type K+ currents, IA, are key determinants of neuronal excitability and several studies suggest a critical role for the Kv4.2 pore-forming α subunit in the generation of IA channels in hippocampal and cortical pyramidal neurons. The experiments here demonstrate that Kv4.2, Kv4.3 and Kv1.4 all contribute to the generation of IA channels in mature cortical pyramidal (CP) neurons and that Kv4.2-, Kv4.3- and Kv1.4-encoded IA channels play distinct roles in regulating the intrinsic excitability and the firing properties of mature CP neurons. In vivo loss of Kv4.2, for example, alters the input resistances, current thresholds for action potential generation and action potential repolarization of mature CP neurons. Elimination of Kv4.3 also prolongs action potential duration, whereas the input resistances and the current thresholds for action potential generation in Kv4.3−/− and WT CP neurons are indistinguishable. In addition, although increased repetitive firing was observed in both Kv4.2−/− and Kv4.3−/− CP neurons, the increases in Kv4.2−/− CP neurons were observed in response to small, but not large, amplitude depolarizing current injections, whereas firing rates were higher in Kv4.3−/− CP neurons only with large amplitude current injections. In vivo loss of Kv1.4, in contrast, had minimal effects on the intrinsic excitability and the firing properties of mature CP neurons. Comparison of the effects of pharmacological blockade of Kv4-encoded currents in Kv1.4−/− and WT CP neurons, however, revealed that Kv1.4-encoded IA channels do contribute to controlling resting membrane potentials, the regulation of current thresholds for action potential generation and repetitive firing rates in mature CP neurons. PMID:22615428

  17. Juvenil neuronal ceroid lipofuscinosis

    DEFF Research Database (Denmark)

    Ostergaard, J R; Hertz, Jens Michael

    1998-01-01

    Neuronal ceroid-lipofuscinosis is a group of neurodegenerative diseases which are characterized by an abnormal accumulation of lipopigment in neuronal and extraneuronal cells. The diseases can be differentiated into several subgroups according to age of onset, the clinical picture...

  18. Developmental time windows for axon growth influence neuronal network topology.

    Science.gov (United States)

    Lim, Sol; Kaiser, Marcus

    2015-04-01

    Early brain connectivity development consists of multiple stages: birth of neurons, their migration and the subsequent growth of axons and dendrites. Each stage occurs within a certain period of time depending on types of neurons and cortical layers. Forming synapses between neurons either by growing axons starting at similar times for all neurons (much-overlapped time windows) or at different time points (less-overlapped) may affect the topological and spatial properties of neuronal networks. Here, we explore the extreme cases of axon formation during early development, either starting at the same time for all neurons (parallel, i.e., maximally overlapped time windows) or occurring for each neuron separately one neuron after another (serial, i.e., no overlaps in time windows). For both cases, the number of potential and established synapses remained comparable. Topological and spatial properties, however, differed: Neurons that started axon growth early on in serial growth achieved higher out-degrees, higher local efficiency and longer axon lengths while neurons demonstrated more homogeneous connectivity patterns for parallel growth. Second, connection probability decreased more rapidly with distance between neurons for parallel growth than for serial growth. Third, bidirectional connections were more numerous for parallel growth. Finally, we tested our predictions with C. elegans data. Together, this indicates that time windows for axon growth influence the topological and spatial properties of neuronal networks opening up the possibility to a posteriori estimate developmental mechanisms based on network properties of a developed network.

  19. Leptin Acts via Lateral Hypothalamic Area Neurotensin Neurons to Inhibit Orexin Neurons by Multiple GABA-Independent Mechanisms

    Science.gov (United States)

    Goforth, Paulette B.; Leinninger, Gina M.; Patterson, Christa M.

    2014-01-01

    The adipocyte-derived hormone leptin modulates neural systems appropriately for the status of body energy stores. Leptin inhibits lateral hypothalamic area (LHA) orexin (OX; also known as hypocretin)-producing neurons, which control feeding, activity, and energy expenditure, among other parameters. Our previous results suggest that GABAergic LHA leptin receptor (LepRb)-containing and neurotensin (Nts)-containing (LepRbNts) neurons lie in close apposition with OX neurons and control Ox mRNA expression. Here, we show that, similar to leptin, activation of LHA Nts neurons by the excitatory hM3Dq DREADD (designer receptor exclusively activated by designer drugs) hyperpolarizes membrane potential and suppresses action potential firing in OX neurons in mouse hypothalamic slices. Furthermore, ablation of LepRb from Nts neurons abrogated the leptin-mediated inhibition, demonstrating that LepRbNts neurons mediate the inhibition of OX neurons by leptin. Leptin did not significantly enhance GABAA-mediated inhibitory synaptic transmission, and GABA receptor antagonists did not block leptin-mediated inhibition of OX neuron activity. Rather, leptin diminished the frequency of spontaneous EPSCs onto OX neurons. Furthermore, leptin indirectly activated an ATP-sensitive potassium (KATP) channel in OX neurons, which was required for the hyperpolarization of OX neurons by leptin. Although Nts did not alter OX activity, galanin, which is coexpressed in LepRbNts neurons, inhibited OX neurons, whereas the galanin receptor antagonist M40 (galanin-(1–12)-Pro3-(Ala-Leu)2-Ala amide) prevented the leptin-induced hyperpolarization of OX cells. These findings demonstrate that leptin indirectly inhibits OX neurons by acting on LHA LepRbNts neurons to mediate two distinct GABA-independent mechanisms of inhibition: the presynaptic inhibition of excitatory neurotransmission and the opening of KATP channels. PMID:25143620

  20. The auditory brainstem is a barometer of rapid auditory learning.

    Science.gov (United States)

    Skoe, E; Krizman, J; Spitzer, E; Kraus, N

    2013-07-23

    To capture patterns in the environment, neurons in the auditory brainstem rapidly alter their firing based on the statistical properties of the soundscape. How this neural sensitivity relates to behavior is unclear. We tackled this question by combining neural and behavioral measures of statistical learning, a general-purpose learning mechanism governing many complex behaviors including language acquisition. We recorded complex auditory brainstem responses (cABRs) while human adults implicitly learned to segment patterns embedded in an uninterrupted sound sequence based on their statistical characteristics. The brainstem's sensitivity to statistical structure was measured as the change in the cABR between a patterned and a pseudo-randomized sequence composed from the same set of sounds but differing in their sound-to-sound probabilities. Using this methodology, we provide the first demonstration that behavioral-indices of rapid learning relate to individual differences in brainstem physiology. We found that neural sensitivity to statistical structure manifested along a continuum, from adaptation to enhancement, where cABR enhancement (patterned>pseudo-random) tracked with greater rapid statistical learning than adaptation. Short- and long-term auditory experiences (days to years) are known to promote brainstem plasticity and here we provide a conceptual advance by showing that the brainstem is also integral to rapid learning occurring over minutes. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  1. DISTINCT MECHANISMS OF INHIBITION OF VSV REPLICATION IN NEURONS MEDIATED BY TYPE I AND TYPE II IFN.

    Science.gov (United States)

    D'Agostino, Paul M; Yang, Jingjun; Reiss, Carol Shoshkes

    2009-01-01

    Acute viral infection of neurons presents a difficult problem to the host, since neurons are essential and not replaced, therefore cell-autonomous pathway(s) of suppressing viral replication are critical. We have examined the mechanisms by which neurons respond to exogenous interferons (IFNs) and observed that novel pathways inhibit acute vesicular stomatitis virus (VSV) replication. For both type I (IFN-beta) and Type II (IFN-gamma) interferons, post-translational modification of viral proteins contributed to the replication blockade, diminishing the efficiency of viral assembly and budding from the host neuron. IFN-gamma treatment induces the accumulation of NOS-1 in the absence of an increase of mRNA encoding this enzyme; a NOS-1-inhibiting protein, PIN, is rapidly ubiquitinated and eliminated in the presence of IFN-gamma. NOS-1 produces NO which combines with superoxide to form peroxynitrite (ONOO-), this binds tyrosines, cysteines, and serines; antagonism of NOS-1 with either non-specific or selective inhibitors block the antiviral effect of IFN-gamma. VSV proteins are decorated with -NO(2) in IFN-gamma-treated neurons, probably resulting in their diminished ability to interact properly and mature into budding virus. For IFN-beta, protein phosphorylation of the Matrix protein (M) and Phosphoprotein (P) were altered in infected neurons, with hyperphosphorylation of M (but not hypophosphorylated P) found in released virions. Hyperphosphorylated M protein does not immunoprecipitate with the viral ribonucleoprotein complex in IFN-beta-treated neurons. Thus both types of IFN interfere with viral assembly and release of infectious particles, but by distinct pathways.

  2. Rapid, long-term labeling of cells in the developing and adult rodent visual cortex using double-stranded adeno-associated viral vectors.

    Science.gov (United States)

    Lowery, Rebecca L; Zhang, Yu; Kelly, Emily A; Lamantia, Cassandra E; Harvey, Brandon K; Majewska, Ania K

    2009-09-01

    Chronic in vivo imaging studies of the brain require a labeling method that is fast, long-lasting, efficient, nontoxic, and cell-type specific. Over the last decade, adeno-associated virus (AAV) has been used to stably express fluorescent proteins in neurons in vivo. However, AAV's main limitation for many studies (such as those of neuronal development) is the necessity of second-strand DNA synthesis, which delays peak transgene expression. The development of double-stranded AAV (dsAAV) vectors has overcome this limitation, allowing rapid transgene expression. Here, we have injected different serotypes (1, 2, 6, 7, 8, and 9) of a dsAAV vector carrying the green fluorescent protein (GFP) gene into the developing and adult mouse visual cortex and characterized its expression. We observed labeling of both neurons and astrocytes with serotype-specific tropism. dsAAV-GFP labeling showed high levels of neuronal GFP expression as early as 2 days postinjection and as long as a month, surpassing conventional AAV's onset of expression and matching its longevity. Neurons labeled with dsAAV-GFP appeared structurally and electrophysiologically identical to nonlabeled neurons, suggesting that dsAAV-GFP is neither cytotoxic nor alters normal neuronal function. We also demonstrated that dsAAV-labeled cells can be imaged with subcellular resolution in vivo over multiple days. We conclude that dsAAV is an excellent vector for rapid labeling and long-term in vivo imaging studies of astrocytes and neurons on the single cell level within the developing and adult visual cortex.

  3. NeuronMetrics: software for semi-automated processing of cultured neuron images.

    Science.gov (United States)

    Narro, Martha L; Yang, Fan; Kraft, Robert; Wenk, Carola; Efrat, Alon; Restifo, Linda L

    2007-03-23

    Using primary cell culture to screen for changes in neuronal morphology requires specialized analysis software. We developed NeuronMetrics for semi-automated, quantitative analysis of two-dimensional (2D) images of fluorescently labeled cultured neurons. It skeletonizes the neuron image using two complementary image-processing techniques, capturing fine terminal neurites with high fidelity. An algorithm was devised to span wide gaps in the skeleton. NeuronMetrics uses a novel strategy based on geometric features called faces to extract a branch number estimate from complex arbors with numerous neurite-to-neurite contacts, without creating a precise, contact-free representation of the neurite arbor. It estimates total neurite length, branch number, primary neurite number, territory (the area of the convex polygon bounding the skeleton and cell body), and Polarity Index (a measure of neuronal polarity). These parameters provide fundamental information about the size and shape of neurite arbors, which are critical factors for neuronal function. NeuronMetrics streamlines optional manual tasks such as removing noise, isolating the largest primary neurite, and correcting length for self-fasciculating neurites. Numeric data are output in a single text file, readily imported into other applications for further analysis. Written as modules for ImageJ, NeuronMetrics provides practical analysis tools that are easy to use and support batch processing. Depending on the need for manual intervention, processing time for a batch of approximately 60 2D images is 1.0-2.5 h, from a folder of images to a table of numeric data. NeuronMetrics' output accelerates the quantitative detection of mutations and chemical compounds that alter neurite morphology in vitro, and will contribute to the use of cultured neurons for drug discovery.

  4. Non-Stationarity in Multisensory Neurons in the Superior Colliculus

    Directory of Open Access Journals (Sweden)

    Thomas J Perrault

    2011-07-01

    Full Text Available The superior colliculus (SC integrates information from multiple sensory modalities to facilitate the detection and localization of salient events. The efficacy of multisensory integration is traditionally measured by comparing the magnitude of the response elicited by a cross-modal stimulus to the responses elicited by its modality-specific component stimuli, and because there is an element of randomness in the system, these calculations are made using response values averaged over multiple stimulus presentations in an experiment. Recent evidence suggests that multisensory integration in the SC is highly plastic and these neurons adapt to specific anomalous stimulus configurations. This raises the question whether such adaptation occurs during an experiment with traditional stimulus configurations; that is, whether the state of the neuron and its integrative principles are the same at the beginning and end of the experiment, or whether they are altered as a consequence of exposure to the testing stimuli even when they are pseudo-randomly interleaved. We find that unisensory and multisensory responses do change during an experiment, and these changes are predictable. Responses that are initially weak tend to potentiate, responses that are initially strong tend to habituate, and the efficacy of multisensory integration waxes or wanes accordingly during the experiment as predicted by the principle of inverse effectiveness. These changes are presumed to reflect two competing mechanisms in the SC: potentiation reflecting increases in the expectation that a stimulus will occur at a given location, habituation reflecting decreases in stimulus novelty. These findings indicate plasticity in multisensory integration that allows animals to adapt to rapidly changing environmental events while suggesting important caveats in the interpretation of experimental data: the neuron studied at the beginning of an experiment is not the same at the end of it.

  5. Expression of dystrophin in the mouse myenteric neurones.

    Science.gov (United States)

    Vannucchi, M G; Corsani, L; Giovannini, M G; Faussone-Pellegrini, M S

    2001-03-09

    Dystrophin, a membrane-associated protein, plays relevant roles in cell functions. Its lack or trunkated expression results in Duchenne muscular dystrophy (DMD), a pathology associated with alterations in gastrointestinal motility considered to be neural in origin. No data are available on the presence of dystrophin in myenteric neurones. We labelled mouse myenteric neurones with DYS1-, DYS2-, DYS3-antibodies; staining was located on the perikarya and processes, with no differences in distribution or intensity among the antibodies; the western immunoblot analysis indicated that myenteric neurones express several dystrophin isoforms; anti-dystrophins/anti-neuronal specific enolase double-labeling confirmed that all neurones express dystrophin. Dystrophin in myenteric neurones might play a role in cytoskeletal organization, axonal transport and signal pathways; its lack might cause the intestinal motor abnormalities reported in DMD patients.

  6. Revisiting the role of neurons in neurovascular coupling

    Directory of Open Access Journals (Sweden)

    Bruno Cauli

    2010-06-01

    Full Text Available In this article, we will review molecular, anatomical, physiological and pharmacological data in an attempt to better understand how excitatory and inhibitory neurons recruited by distinct afferent inputs to the cerebral cortex contribute to the coupled hemodynamic response, and how astrocytes can act as intermediaries to these neuronal populations. We aim at providing the pros and cons to the following statements that, depending on the nature of the afferent input to the neocortex, (i different neuronal or astroglial messengers, likely acting in sequence, mediate the hemodynamic changes, (ii some recruited neurons release messengers that directly alter blood vessel tone, (iii others act by modulating neuronal and astroglial activity, and (iv astrocytes act as intermediaries for both excitatory and inhibitory neurotransmitters. We will stress that a given afferent signal activates a precise neuronal circuitry that determines the mediators of the hemodynamic response as well as the level of interaction with surrounding astrocytes.

  7. New insights of altered lipid profile in Fragile X Syndrome

    National Research Council Canada - National Science Library

    Artuela Çaku; Nabil G Seidah; Audrey Lortie; Nancy Gagné; Patrice Perron; Jean Dubé; Francois Corbin

    2017-01-01

    .... Since lipids are important for neuronal development, we aim to investigate the lipid profile of French Canadian-FXS individuals and to identify the altered components of cholesterol metabolism...

  8. Functional maps within a single neuron

    Science.gov (United States)

    Johnston, Daniel

    2012-01-01

    The presence and plasticity of dendritic ion channels are well established. However, the literature is divided on what specific roles these dendritic ion channels play in neuronal information processing, and there is no consensus on why neuronal dendrites should express diverse ion channels with different expression profiles. In this review, we present a case for viewing dendritic information processing through the lens of the sensory map literature, where functional gradients within neurons are considered as maps on the neuronal topograph. Under such a framework, drawing analogies from the sensory map literature, we postulate that the formation of intraneuronal functional maps is driven by the twin objectives of efficiently encoding inputs that impinge along different dendritic locations and of retaining homeostasis in the face of changes that are required in the coding process. In arriving at this postulate, we relate intraneuronal map physiology to the vast literature on sensory maps and argue that such a metaphorical association provides a fresh conceptual framework for analyzing and understanding single-neuron information encoding. We also describe instances where the metaphor presents specific directions for research on intraneuronal maps, derived from analogous pursuits in the sensory map literature. We suggest that this perspective offers a thesis for why neurons should express and alter ion channels in their dendrites and provides a framework under which active dendrites could be related to neural coding, learning theory, and homeostasis. PMID:22933729

  9. Dynamics of Phosphoinositide-Dependent Signaling in Sympathetic Neurons

    Science.gov (United States)

    Kruse, Martin; Vivas, Oscar; Traynor-Kaplan, Alexis

    2016-01-01

    In neurons, loss of plasma membrane phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] leads to a decrease in exocytosis and changes in electrical excitability. Restoration of PI(4,5)P2 levels after phospholipase C activation is therefore essential for a return to basal neuronal activity. However, the dynamics of phosphoinositide metabolism have not been analyzed in neurons. We measured dynamic changes of PI(4,5)P2, phosphatidylinositol 4-phosphate, diacylglycerol, inositol 1,4,5-trisphosphate, and Ca2+ upon muscarinic stimulation in sympathetic neurons from adult male Sprague-Dawley rats with electrophysiological and optical approaches. We used this kinetic information to develop a quantitative description of neuronal phosphoinositide metabolism. The measurements and analysis show and explain faster synthesis of PI(4,5)P2 in sympathetic neurons than in electrically nonexcitable tsA201 cells. They can be used to understand dynamic effects of receptor-mediated phospholipase C activation on excitability and other PI(4,5)P2-dependent processes in neurons. SIGNIFICANCE STATEMENT Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a minor phospholipid in the cytoplasmic leaflet of the plasma membrane. Depletion of PI(4,5)P2 via phospholipase C-mediated hydrolysis leads to a decrease in exocytosis and alters electrical excitability in neurons. Restoration of PI(4,5)P2 is essential for a return to basal neuronal activity. However, the dynamics of phosphoinositide metabolism have not been analyzed in neurons. We studied the dynamics of phosphoinositide metabolism in sympathetic neurons upon muscarinic stimulation and used the kinetic information to develop a quantitative description of neuronal phosphoinositide metabolism. The measurements and analysis show a several-fold faster synthesis of PI(4,5)P2 in sympathetic neurons than in an electrically nonexcitable cell line, and provide a framework for future studies of PI(4,5)P2-dependent processes in neurons. PMID:26818524

  10. Regulation/modulation of sensory neuron sodium channels.

    Science.gov (United States)

    Chahine, Mohamed; O'Leary, Michael E

    2014-01-01

    The pseudounipolar sensory neurons of the dorsal root ganglia (DRG) give rise to peripheral branches that convert thermal, mechanical, and chemical stimuli into electrical signals that are transmitted via central branches to the spinal cord. These neurons express unique combinations of tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) Na(+) channels that contribute to the resting membrane potential, action potential threshold, and regulate neuronal firing frequency. The small-diameter neurons (35 μm) are typically low-threshold A-fibers that predominately express TTX-S Na(+) currents. Peripheral nerve damage, inflammation, and metabolic diseases alter the expression and function of these Na(+) channels leading to increases in neuronal excitability and pain. The Na(+) channels expressed in these neurons are the target of intracellular signaling cascades that regulate the trafficking, cell surface expression, and gating properties of these channels. Post-translational regulation of Na(+) channels by protein kinases (PKA, PKC, MAPK) alter the expression and function of the channels. Injury-induced changes in these signaling pathways have been linked to sensory neuron hyperexcitability and pain. This review examines the signaling pathways and regulatory mechanisms that modulate the voltage-gated Na(+) channels of sensory neurons.

  11. Microglia in neuronal plasticity: Influence of stress.

    Science.gov (United States)

    Delpech, Jean-Christophe; Madore, Charlotte; Nadjar, Agnes; Joffre, Corinne; Wohleb, Eric S; Layé, Sophie

    2015-09-01

    The central nervous system (CNS) has previously been regarded as an immune-privileged site with the absence of immune cell responses but this dogma was not entirely true. Microglia are the brain innate immune cells and recent findings indicate that they participate both in CNS disease and infection as well as facilitate normal CNS function. Microglia are highly plastic and play integral roles in sculpting the structure of the CNS, refining neuronal circuitry and connectivity, and contribute actively to neuronal plasticity in the healthy brain. Interestingly, psychological stress can perturb the function of microglia in association with an impaired neuronal plasticity and the development of emotional behavior alterations. As a result it seemed important to describe in this review some findings indicating that the stress-induced microglia dysfunction may underlie neuroplasticity deficits associated to many mood disorders. This article is part of a Special Issue entitled 'Neuroimmunology and Synaptic Function'. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Operant self-stimulation of dopamine neurons in the substantia nigra.

    Directory of Open Access Journals (Sweden)

    Mark A Rossi

    Full Text Available We examined the contribution of the nigrostriatal DA system to instrumental learning and behavior using optogenetics in awake, behaving mice. Using Cre-inducible channelrhodopsin-2 (ChR2 in mice expressing Cre recombinase driven by the tyrosine hydroxylase promoter (Th-Cre, we tested whether selective stimulation of DA neurons in the substantia nigra pars compacta (SNC, in the absence of any natural rewards, was sufficient to promote instrumental learning in naive mice. Mice expressing ChR2 in SNC DA neurons readily learned to press a lever to receive laser stimulation, but unlike natural food rewards the lever pressing did not decline with satiation. When the number of presses required to receive a stimulation was altered, mice adjusted their rate of pressing accordingly, suggesting that the rate of stimulation was a controlled variable. Moreover, extinction, i.e. the cessation of action-contingent stimulation, and the complete reversal of the relationship between action and outcome by the imposition of an omission contingency, rapidly abolished lever pressing. Together these results suggest that selective activation of SNC DA neurons can be sufficient for acquisition and maintenance of a new instrumental action.

  13. Minocycline inhibits hyperpolarization-activated currents in rat substantia gelatinosa neurons.

    Science.gov (United States)

    Liu, Nana; Zhang, Daying; Zhu, Mengye; Luo, Shiwen; Liu, Tao

    2015-08-01

    Minocycline is a widely used glial activation inhibitor that could suppress pain-related behaviors in a number of different pain animal models, yet, its analgesic mechanisms are not fully understood. Hyperpolarization-activated cation channel-induced Ih current plays an important role in neuronal excitability and pathological pain. In this study, we investigated the possible effect of minocycline on Ih of substantia gelatinosa neuron in superficial spinal dorsal horn by using whole-cell patch-clamp recording. We found that extracellular minocycline rapidly decreases Ih amplitude in a reversible and concentration-dependent manner (IC50 = 41 μM). By contrast, intracellular minocycline had no effect. Minocycline-induced inhibition of Ih was not affected by Na(+) channel blocker tetrodotoxin, glutamate-receptor antagonists (CNQX and D-APV), GABAA receptor antagonist (bicuculine methiodide), or glycine receptor antagonist (strychnine). Minocycline also caused a negative shift in the activation curve of Ih, but did not alter the reversal potential. Moreover, minocycline slowed down the inter-spike depolarizing slope and produced a robust decrease in the rate of action potential firing. Together, these results illustrate a novel cellular mechanism underlying minocycline's analgesic effect by inhibiting Ih currents of spinal dorsal horn neurons. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Dynamin-related protein 1 is required for normal mitochondrial bioenergetic and synaptic function in CA1 hippocampal neurons.

    Science.gov (United States)

    Shields, L Y; Kim, H; Zhu, L; Haddad, D; Berthet, A; Pathak, D; Lam, M; Ponnusamy, R; Diaz-Ramirez, L G; Gill, T M; Sesaki, H; Mucke, L; Nakamura, K

    2015-04-16

    Disrupting particular mitochondrial fission and fusion proteins leads to the death of specific neuronal populations; however, the normal functions of mitochondrial fission in neurons are poorly understood, especially in vivo, which limits the understanding of mitochondrial changes in disease. Altered activity of the central mitochondrial fission protein dynamin-related protein 1 (Drp1) may contribute to the pathophysiology of several neurologic diseases. To study Drp1 in a neuronal population affected by Alzheimer's disease (AD), stroke, and seizure disorders, we postnatally deleted Drp1 from CA1 and other forebrain neurons in mice (CamKII-Cre, Drp1lox/lox (Drp1cKO)). Although most CA1 neurons survived for more than 1 year, their synaptic transmission was impaired, and Drp1cKO mice had impaired memory. In Drp1cKO cell bodies, we observed marked mitochondrial swelling but no change in the number of mitochondria in individual synaptic terminals. Using ATP FRET sensors, we found that cultured neurons lacking Drp1 (Drp1KO) could not maintain normal levels of mitochondrial-derived ATP when energy consumption was increased by neural activity. These deficits occurred specifically at the nerve terminal, but not the cell body, and were sufficient to impair synaptic vesicle cycling. Although Drp1KO increased the distance between axonal mitochondria, mitochondrial-derived ATP still decreased similarly in Drp1KO boutons with and without mitochondria. This indicates that mitochondrial-derived ATP is rapidly dispersed in Drp1KO axons, and that the deficits in axonal bioenergetics and function are not caused by regional energy gradients. Instead, loss of Drp1 compromises the intrinsic bioenergetic function of axonal mitochondria, thus revealing a mechanism by which disrupting mitochondrial dynamics can cause dysfunction of axons.

  15. Dynamic GABAergic afferent modulation of AgRP neurons.

    Science.gov (United States)

    Garfield, Alastair S; Shah, Bhavik P; Burgess, Christian R; Li, Monica M; Li, Chia; Steger, Jennifer S; Madara, Joseph C; Campbell, John N; Kroeger, Daniel; Scammell, Thomas E; Tannous, Bakhos A; Myers, Martin G; Andermann, Mark L; Krashes, Michael J; Lowell, Bradford B

    2016-12-01

    Agouti-related peptide (AgRP) neurons of the arcuate nucleus of the hypothalamus (ARC) promote homeostatic feeding at times of caloric insufficiency, yet they are rapidly suppressed by food-related sensory cues before ingestion. Here we identify a highly selective inhibitory afferent to AgRP neurons that serves as a neural determinant of this rapid modulation. Specifically, GABAergic projections arising from the ventral compartment of the dorsomedial nucleus of the hypothalamus (vDMH) contribute to the preconsummatory modulation of ARCAgRP neurons. In a manner reciprocal to ARCAgRP neurons, ARC-projecting leptin receptor-expressing GABAergic vDMH neurons exhibit rapid activation upon availability of food that additionally reflects the relative value of the food. Thus, leptin receptor-expressing GABAergic vDMH neurons form part of the sensory network that relays real-time information about the nature and availability of food to dynamically modulate ARCAgRP neuron activity and feeding behavior.

  16. Circadian integration of sleep-wake and feeding requires NPY receptor-expressing neurons in the mediobasal hypothalamus.

    Science.gov (United States)

    Wiater, M F; Mukherjee, S; Li, A-J; Dinh, T T; Rooney, E M; Simasko, S M; Ritter, S

    2011-11-01

    Sleep and feeding rhythms are highly coordinated across the circadian cycle, but the brain sites responsible for this coordination are unknown. We examined the role of neuropeptide Y (NPY) receptor-expressing neurons in the mediobasal hypothalamus (MBH) in this process by injecting the targeted toxin, NPY-saporin (NPY-SAP), into the arcuate nucleus (Arc). NPY-SAP-lesioned rats were initially hyperphagic, became obese, exhibited sustained disruption of circadian feeding patterns, and had abnormal circadian distribution of sleep-wake patterns. Total amounts of rapid eye movement sleep (REMS) and non-REMS (NREMS) were not altered by NPY-SAP lesions, but a peak amount of REMS was permanently displaced to the dark period, and circadian variation in NREMS was eliminated. The phase reversal of REMS to the dark period by the lesion suggests that REMS timing is independently linked to the function of MBH NPY receptor-expressing neurons and is not dependent on NREMS pattern, which was altered but not phase reversed by the lesion. Sleep-wake patterns were altered in controls by restricting feeding to the light period, but were not altered in NPY-SAP rats by restricting feeding to either the light or dark period, indicating that disturbed sleep-wake patterns in lesioned rats were not secondary to changes in food intake. Sleep abnormalities persisted even after hyperphagia abated during the static phase of the lesion. Results suggest that the MBH is required for the essential task of integrating sleep-wake and feeding rhythms, a function that allows animals to accommodate changeable patterns of food availability. NPY receptor-expressing neurons are key components of this integrative function.

  17. NEURON and Python.

    Science.gov (United States)

    Hines, Michael L; Davison, Andrew P; Muller, Eilif

    2009-01-01

    The NEURON simulation program now allows Python to be used, alone or in combination with NEURON's traditional Hoc interpreter. Adding Python to NEURON has the immediate benefit of making available a very extensive suite of analysis tools written for engineering and science. It also catalyzes NEURON software development by offering users a modern programming tool that is recognized for its flexibility and power to create and maintain complex programs. At the same time, nothing is lost because all existing models written in Hoc, including graphical user interface tools, continue to work without change and are also available within the Python context. An example of the benefits of Python availability is the use of the xml module in implementing NEURON's Import3D and CellBuild tools to read MorphML and NeuroML model specifications.

  18. Rapid intermittent movement of axonal neurofilaments observed by fluorescence photobleaching

    National Research Council Canada - National Science Library

    Wang, L; Brown, A

    2001-01-01

    Observations on naturally occurring gaps in the axonal neurofilament array of cultured neurons have demonstrated that neurofilament polymers move along axons in a rapid, intermittent, and highly asynchronous manner...

  19. Rewiring Neuronal Circuits: A New Method for Fast Neurite Extension and Functional Neuronal Connection.

    Science.gov (United States)

    Magdesian, Margaret H; Anthonisen, Madeleine; Lopez-Ayon, G Monserratt; Chua, Xue Ying; Rigby, Matthew; Grütter, Peter

    2017-06-13

    Brain and spinal cord injury may lead to permanent disability and death because it is still not possible to regenerate neurons over long distances and accurately reconnect them with an appropriate target. Here a procedure is described to rapidly initiate, elongate, and precisely connect new functional neuronal circuits over long distances. The extension rates achieved reach over 1.2 mm/h, 30-60 times faster than the in vivo rates of the fastest growing axons from the peripheral nervous system (0.02 to 0.04 mm/h)(28) and 10 times faster than previously reported for the same neuronal type at an earlier stage of development(4). First, isolated populations of rat hippocampal neurons are grown for 2-3 weeks in microfluidic devices to precisely position the cells, enabling easy micromanipulation and experimental reproducibility. Next, beads coated with poly-D-lysine (PDL) are placed on neurites to form adhesive contacts and pipette micromanipulation is used to move the resulting bead-neurite complex. As the bead is moved, it pulls out a new neurite that can be extended over hundreds of micrometers and functionally connected to a target cell in less than 1 h. This process enables experimental reproducibility and ease of manipulation while bypassing slower chemical strategies to induce neurite growth. Preliminary measurements presented here demonstrate a neuronal growth rate far exceeding physiological ones. Combining these innovations allows for the precise establishment of neuronal networks in culture with an unprecedented degree of control. It is a novel method that opens the door to a plethora of information and insights into signal transmission and communication within the neuronal network as well as being a playground in which to explore the limits of neuronal growth. The potential applications and experiments are widespread with direct implications for therapies that aim to reconnect neuronal circuits after trauma or in neurodegenerative diseases.

  20. Corazonin neurons function in sexually dimorphic circuitry that shape behavioral responses to stress in Drosophila.

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    Full Text Available All organisms are confronted with dynamic environmental changes that challenge homeostasis, which is the operational definition of stress. Stress produces adaptive behavioral and physiological responses, which, in the Metazoa, are mediated through the actions of various hormones. Based on its associated phenotypes and its expression profiles, a candidate stress hormone in Drosophila is the corazonin neuropeptide. We evaluated the potential roles of corazonin in mediating stress-related changes in target behaviors and physiologies through genetic alteration of corazonin neuronal excitability. Ablation of corazonin neurons confers resistance to metabolic, osmotic, and oxidative stress, as measured by survival. Silencing and activation of corazonin neurons lead to differential lifespan under stress, and these effects showed a strong dependence on sex. Additionally, altered corazonin neuron physiology leads to fundamental differences in locomotor activity, and these effects were also sex-dependent. The dynamics of altered locomotor behavior accompanying stress was likewise altered in flies with altered corazonin neuronal function. We report that corazonin transcript expression is altered under starvation and osmotic stress, and that triglyceride and dopamine levels are equally impacted in corazonin neuronal alterations and these phenotypes similarly show significant sexual dimorphisms. Notably, these sexual dimorphisms map to corazonin neurons. These results underscore the importance of central peptidergic processing within the context of stress and place corazonin signaling as a critical feature of neuroendocrine events that shape stress responses and may underlie the inherent sexual dimorphic differences in stress responses.

  1. Nanomolar ouabain augments Ca2+ signalling in rat hippocampal neurones and glia

    Science.gov (United States)

    Song, Hong; Thompson, Scott M; Blaustein, Mordecai P

    2013-01-01

    Linkage of certain neurological diseases to Na+ pump mutations and some mood disorders to altered Na+ pump function has renewed interest in brain Na+ pumps. We tested nanomolar ouabain on Ca2+ signalling (fura-2) in rat hippocampal neurone–astrocyte co-cultures. The neurones and astrocytes express Na+ pumps with a high-ouabain-affinity catalytic subunit (α3 and α2, respectively); both also express pumps with a ouabain-resistant α1 subunit. Neurones and astrocytes were identified by immunocytochemistry and by stimulation; 3–4 μm l-glutamate (Glu) and 3 μm carbachol (CCh) evoked rapid Ca2+ transients only in neurones, and small, delayed transients in some astrocytes, whereas 0.5–1 μm ATP evoked Ca2+ transients only in astrocytes. Both cell types responded to 5–10 μm Glu or ATP. The signals evoked by 3–4 μm Glu in neurones were markedly inhibited by 3–10 μm MPEP (blocks metabotropic glutamate receptor mGluR5) and 10 μm LY341495 (non-selective mGluR blocker), but not by 80 μm AP5 (NMDA receptor blocker) or by selective block of mGluR1 or mGluR2. Pre-incubation (0.5–10 min) with 1–10 nm ouabain (EC50 neurones. This augmentation was abolished by a blocker of the Na+–Ca2+ exchanger, SEA0400 (300 nm). Ouabain (3 nm) pre-incubation also augmented 10 μm cyclopiazonic acid plus 10 mm caffeine-evoked release of Ca2+ from the neuronal endoplasmic reticulum (ER). The implication is that nanomolar ouabain inhibits α3 Na+ pumps, increases (local) intracellular Na+, and promotes Na+–Ca2+ exchanger-mediated Ca2+ gain and increased storage in the adjacent ER. Ouabain (3 nm) also increased ER Ca2+ release and enhanced 0.5 μm ATP-evoked transients in astrocytes; these effects were mediated by α2 Na+ pumps. Thus, nanomolar ouabain may strongly influence synaptic transmission in the brain as a result of its actions on the high-ouabain-affinity Na+ pumps in both neurones and astrocytes. The significance of these effects is heightened by the evidence that

  2. Neuronal Cholesterol Accumulation Induced by Cyp46a1 Down-Regulation in Mouse Hippocampus Disrupts Brain Lipid Homeostasis

    Directory of Open Access Journals (Sweden)

    Sophie Ayciriex

    2017-07-01

    Full Text Available Impairment in cholesterol metabolism is associated with many neurodegenerative disorders including Alzheimer's disease (AD. However, the lipid alterations underlying neurodegeneration and the connection between altered cholesterol levels and AD remains not fully understood. We recently showed that cholesterol accumulation in hippocampal neurons, induced by silencing Cyp46a1 gene expression, leads to neurodegeneration with a progressive neuronal loss associated with AD-like phenotype in wild-type mice. We used a targeted and non-targeted lipidomics approach by liquid chromatography coupled to high-resolution mass spectrometry to further characterize lipid modifications associated to neurodegeneration and cholesterol accumulation induced by CYP46A1 inhibition. Hippocampus lipidome of normal mice was profiled 4 weeks after cholesterol accumulation due to Cyp46a1 gene expression down-regulation at the onset of neurodegeneration. We showed that major membrane lipids, sphingolipids and specific enzymes involved in phosphatidylcholine and sphingolipid metabolism, were rapidly increased in the hippocampus of AAV-shCYP46A1 injected mice. This lipid accumulation was associated with alterations in the lysosomal cargoe, accumulation of phagolysosomes and impairment of endosome-lysosome trafficking. Altogether, we demonstrated that inhibition of cholesterol 24-hydroxylase, key enzyme of cholesterol metabolism leads to a complex dysregulation of lipid homeostasis. Our results contribute to dissect the potential role of lipids in severe neurodegenerative diseases like AD.

  3. Toxoplasma gondii actively inhibits neuronal function in chronically infected mice.

    Directory of Open Access Journals (Sweden)

    Fahad Haroon

    Full Text Available Upon infection with the obligate intracellular parasite Toxoplasma gondii, fast replicating tachyzoites infect a broad spectrum of host cells including neurons. Under the pressure of the immune response, tachyzoites convert into slow-replicating bradyzoites, which persist as cysts in neurons. Currently, it is unclear whether T. gondii alters the functional activity of neurons, which may contribute to altered behaviour of T. gondii-infected mice and men. In the present study we demonstrate that upon oral infection with T. gondii cysts, chronically infected BALB/c mice lost over time their natural fear against cat urine which was paralleled by the persistence of the parasite in brain regions affecting behaviour and odor perception. Detailed immunohistochemistry showed that in infected neurons not only parasitic cysts but also the host cell cytoplasm and some axons stained positive for Toxoplasma antigen suggesting that parasitic proteins might directly interfere with neuronal function. In fact, in vitro live cell calcium (Ca(2+ imaging studies revealed that tachyzoites actively manipulated Ca(2+ signalling upon glutamate stimulation leading either to hyper- or hypo-responsive neurons. Experiments with the endoplasmatic reticulum Ca(2+ uptake inhibitor thapsigargin indicate that tachyzoites deplete Ca(2+ stores in the endoplasmatic reticulum. Furthermore in vivo studies revealed that the activity-dependent uptake of the potassium analogue thallium was reduced in cyst harbouring neurons indicating their functional impairment. The percentage of non-functional neurons increased over time In conclusion, both bradyzoites and tachyzoites functionally silence infected neurons, which may significantly contribute to the altered behaviour of the host.

  4. Toxoplasma gondii Actively Inhibits Neuronal Function in Chronically Infected Mice

    Science.gov (United States)

    Haroon, Fahad; Händel, Ulrike; Angenstein, Frank; Goldschmidt, Jürgen; Kreutzmann, Peter; Lison, Holger; Fischer, Klaus-Dieter; Scheich, Henning; Wetzel, Wolfram; Schlüter, Dirk; Budinger, Eike

    2012-01-01

    Upon infection with the obligate intracellular parasite Toxoplasma gondii, fast replicating tachyzoites infect a broad spectrum of host cells including neurons. Under the pressure of the immune response, tachyzoites convert into slow-replicating bradyzoites, which persist as cysts in neurons. Currently, it is unclear whether T. gondii alters the functional activity of neurons, which may contribute to altered behaviour of T. gondii–infected mice and men. In the present study we demonstrate that upon oral infection with T. gondii cysts, chronically infected BALB/c mice lost over time their natural fear against cat urine which was paralleled by the persistence of the parasite in brain regions affecting behaviour and odor perception. Detailed immunohistochemistry showed that in infected neurons not only parasitic cysts but also the host cell cytoplasm and some axons stained positive for Toxoplasma antigen suggesting that parasitic proteins might directly interfere with neuronal function. In fact, in vitro live cell calcium (Ca2+) imaging studies revealed that tachyzoites actively manipulated Ca2+ signalling upon glutamate stimulation leading either to hyper- or hypo-responsive neurons. Experiments with the endoplasmatic reticulum Ca2+ uptake inhibitor thapsigargin indicate that tachyzoites deplete Ca2+ stores in the endoplasmatic reticulum. Furthermore in vivo studies revealed that the activity-dependent uptake of the potassium analogue thallium was reduced in cyst harbouring neurons indicating their functional impairment. The percentage of non-functional neurons increased over time In conclusion, both bradyzoites and tachyzoites functionally silence infected neurons, which may significantly contribute to the altered behaviour of the host. PMID:22530040

  5. Monoaminergic and neuropeptidergic neurons have distinct expression profiles of histone deacetylases.

    Directory of Open Access Journals (Sweden)

    Kenkichi Takase

    Full Text Available Monoaminergic and neuropeptidergic neurons regulate a wide variety of behaviors, such as feeding, sleep/wakefulness behavior, stress response, addiction, and social behavior. These neurons form neural circuits to integrate different modalities of behavioral and environmental factors, such as stress, maternal care, and feeding conditions. One possible mechanism for integrating environmental factors through the monoaminergic and neuropeptidergic neurons is through the epigenetic regulation of gene expression via altered acetylation of histones. Histone deacetylases (HDACs play an important role in altering behavior in response to environmental factors. Despite increasing attention and the versatile roles of HDACs in a variety of brain functions and disorders, no reports have detailed the localization of the HDACs in the monoaminergic and neuropeptidergic neurons. Here, we examined the expression profile of the HDAC protein family from HDAC1 to HDAC11 in corticotropin-releasing hormone, oxytocin, vasopressin, agouti-related peptide (AgRP, pro-opiomelanocortin (POMC, orexin, histamine, dopamine, serotonin, and noradrenaline neurons. Immunoreactivities for HDAC1,-2,-3,-5,-6,-7,-9, and -11 were very similar among the monoaminergic and neuropeptidergic neurons, while the HDAC4, -8, and -10 immunoreactivities were clearly different among neuronal groups. HDAC10 expression was found in AgRP neurons, POMC neurons, dopamine neurons and noradrenaline neurons but not in other neuronal groups. HDAC8 immunoreactivity was detected in the cytoplasm of almost all histamine neurons with a pericellular pattern but not in other neuropeptidergic and monoaminergic neurons. Thus, the differential expression of HDACs in monoaminergic and neuropeptidergic neurons may be crucial for the maintenance of biological characteristics and may be altered in response to environmental factors.

  6. Rapid Prototyping

    Science.gov (United States)

    1999-01-01

    Javelin, a Lone Peak Engineering Inc. Company has introduced the SteamRoller(TM) System as a commercial product. The system was designed by Javelin during a Phase II NASA funded small commercial product. The purpose of the invention was to allow automated-feed of flexible ceramic tapes to the Laminated Object Manufacturing rapid prototyping equipment. The ceramic material that Javelin was working with during the Phase II project is silicon nitride. This engineered ceramic material is of interest for space-based component.

  7. Long-lasting distortion of GABA signaling in MS/DB neurons after binge-like ethanol exposure during initial synaptogenesis

    Science.gov (United States)

    Wang, Haiying; DuBois, Dustin W.; Tobery, Angelika N.; Griffith, William H.; Brandt, Paul; Frye, Gerald D.

    2013-01-01

    Using a well-established model of binge-like ethanol treatment of rat pups on postnatal days (PD) 4–9, we found that maturation of GABAA receptor (GABAAR) miniature postsynaptic currents (mPSCs) was substantially blunted for medial septum/diagonal band (MS/DB) neurons in brain slices on PD 11–16. Ethanol reduced mPSC amplitude, frequency, and decay kinetics, while attenuating or exaggerating allosteric actions of zolpidem and allopregnanolone, respectively. The impact of ethanol in vivo was long lasting as most changes in MS/DB GABAAR mPSCs were still observed as late as PD 60–85. Maturing MS/DB neurons in naïve brain slices PD 4–16 showed increasing mPSC frequency, decay kinetics, and zolpidem sensitivity that were nearly identical to our earlier findings in cultured septal neurons [17, 18]. These rapidly developing mPSC parameters continued to mature through the first month of life then stabilized throughout the remainder of the lifespan. Finally, equivalent ethanol-induced alterations in GABAAR mPSC signaling were present in MS/DB neurons from both male and female animals. Previously, we showed ethanol treatment of cultured embryonic day 20 septal neurons distorts the maturation of GABAAR mPSCs predicting that early stages of GABAergic transmission in MS/DB neurons are vulnerable to intoxication injury [17, 18]. Since the overall character, timing, and magnitude of GABAergic mPSC developmental- and ethanol-induced changes in the in vivo model so closely mirror chronologically equivalent adaptations in cultured septal neurons, this suggests that such parallel models of ethanol impairment of GABAergic synaptic development in vivo and in vitro should be useful for translational studies exploring the efficacy and mechanism of action of potential therapeutic interventions from the cellular to whole animal level. PMID:23685190

  8. A mammalian nervous system-specific plasma membrane proteasome complex that modulates neuronal function

    Science.gov (United States)

    Ramachandran, Kapil V.; Margolis, Seth S.

    2017-01-01

    In the nervous system, rapidly occurring processes such as neuronal transmission and calcium signaling are affected by short-term inhibition of proteasome function. It remains unclear how proteasomes can acutely regulate such processes, as this is inconsistent with their canonical role in proteostasis. Here, we made the discovery of a mammalian nervous system-specific membrane proteasome complex that directly and rapidly modulates neuronal function by degrading intracellular proteins into extracellular peptides that can stimulate neuronal signaling. This proteasome complex is tightly associated with neuronal plasma membranes, exposed to the extracellular space, and catalytically active. Selective inhibition of this membrane proteasome complex by a cell-impermeable proteasome inhibitor blocked extracellular peptide production and attenuated neuronal activity-induced calcium signaling. Moreover, membrane proteasome-derived peptides are sufficient to induce neuronal calcium signaling. Our discoveries challenge the prevailing notion that proteasomes primarily function to maintain proteostasis, and highlight a form of neuronal communication through a membrane proteasome complex. PMID:28287632

  9. Motor neuron disease after electric injury

    Science.gov (United States)

    Jafari, H; Couratier, P; Camu, W

    2001-01-01

    The occurrence of motor neuron disease after electrical injury in six patients is reported and compared with patients from the literature. The patients were five men with spinal onset and one woman with bulbar motor neuron disease after electric shock. Two patients were struck by lightning and four by industrial electric shock. For all six of them, the disease started at the site of the electrical trauma. The mean delay for onset of motor neuron disease was 44 months. In four of the spinal patients the disease progressed slowly with mild handicap after several years. For the fifth patient, improvement was noted progressively. The patient with bulbar disease died 26 months after onset. A link between electric shock and motor neuron disease is likely, given the homogenous profile of the patients both in the five spinal cases presented here and in the literature. Bulbar onset has not been reported to date. However, in this patient the long delay between the electrical injury and motor neuron disease, together with the rapid evolution may suggest a chance association.

 PMID:11459909

  10. Electrophysiological properties of embryonic stem cell-derived neurons.

    Directory of Open Access Journals (Sweden)

    Jessica R Risner-Janiczek

    Full Text Available In vitro generation of functional neurons from embryonic stem (ES cells and induced pluripotent stem cells offers exciting opportunities for dissecting gene function, disease modelling, and therapeutic drug screening. To realize the potential of stem cells in these biomedical applications, a complete understanding of the cell models of interest is required. While rapid advances have been made in developing the technologies for directed induction of defined neuronal subtypes, most published works focus on the molecular characterization of the derived neural cultures. To characterize the functional properties of these neural cultures, we utilized an ES cell model that gave rise to neurons expressing the green fluorescent protein (GFP and conducted targeted whole-cell electrophysiological recordings from ES cell-derived neurons. Current-clamp recordings revealed that most neurons could fire single overshooting action potentials; in some cases multiple action potentials could be evoked by depolarization, or occurred spontaneously. Voltage-clamp recordings revealed that neurons exhibited neuronal-like currents, including an outward current typical of a delayed rectifier potassium conductance and a fast-activating, fast-inactivating inward current, typical of a sodium conductance. Taken together, these results indicate that ES cell-derived GFP(+ neurons in culture display functional neuronal properties even at early stages of differentiation.

  11. Electrolyte-gated organic synapse transistor interfaced with neurons

    CERN Document Server

    Desbief, Simon; Casalini, Stefano; Guerin, David; Tortorella, Silvia; Barbalinardo, Marianna; Kyndiah, Adrica; Murgia, Mauro; Cramer, Tobias; Biscarini, Fabio; Vuillaume, Dominique

    2016-01-01

    We demonstrate an electrolyte-gated hybrid nanoparticle/organic synapstor (synapse-transistor, termed EGOS) that exhibits short-term plasticity as biological synapses. The response of EGOS makes it suitable to be interfaced with neurons: short-term plasticity is observed at spike voltage as low as 50 mV (in a par with the amplitude of action potential in neurons) and with a typical response time in the range of tens milliseconds. Human neuroblastoma stem cells are adhered and differentiated into neurons on top of EGOS. We observe that the presence of the cells does not alter short-term plasticity of the device.

  12. Single neuron computation

    CERN Document Server

    McKenna, Thomas M; Zornetzer, Steven F

    1992-01-01

    This book contains twenty-two original contributions that provide a comprehensive overview of computational approaches to understanding a single neuron structure. The focus on cellular-level processes is twofold. From a computational neuroscience perspective, a thorough understanding of the information processing performed by single neurons leads to an understanding of circuit- and systems-level activity. From the standpoint of artificial neural networks (ANNs), a single real neuron is as complex an operational unit as an entire ANN, and formalizing the complex computations performed by real n

  13. Semi-automatic classification of skeletal morphology in genetically altered mice using flat-panel volume computed tomography.

    Directory of Open Access Journals (Sweden)

    Christian Dullin

    2007-07-01

    Full Text Available Rapid progress in exploring the human and mouse genome has resulted in the generation of a multitude of mouse models to study gene functions in their biological context. However, effective screening methods that allow rapid noninvasive phenotyping of transgenic and knockout mice are still lacking. To identify murine models with bone alterations in vivo, we used flat-panel volume computed tomography (fpVCT for high-resolution 3-D imaging and developed an algorithm with a computational intelligence system. First, we tested the accuracy and reliability of this approach by imaging discoidin domain receptor 2- (DDR2- deficient mice, which display distinct skull abnormalities as shown by comparative landmark-based analysis. High-contrast fpVCT data of the skull with 200 microm isotropic resolution and 8-s scan time allowed segmentation and computation of significant shape features as well as visualization of morphological differences. The application of a trained artificial neuronal network to these datasets permitted a semi-automatic and highly accurate phenotype classification of DDR2-deficient compared to C57BL/6 wild-type mice. Even heterozygous DDR2 mice with only subtle phenotypic alterations were correctly determined by fpVCT imaging and identified as a new class. In addition, we successfully applied the algorithm to classify knockout mice lacking the DDR1 gene with no apparent skull deformities. Thus, this new method seems to be a potential tool to identify novel mouse phenotypes with skull changes from transgenic and knockout mice on the basis of random mutagenesis as well as from genetic models. However for this purpose, new neuronal networks have to be created and trained. In summary, the combination of fpVCT images with artificial neuronal networks provides a reliable, novel method for rapid, cost-effective, and noninvasive primary screening tool to detect skeletal phenotypes in mice.

  14. Single-neuron NMDA receptor phenotype influences neuronal rewiring and reintegration following traumatic injury.

    Science.gov (United States)

    Patel, Tapan P; Ventre, Scott C; Geddes-Klein, Donna; Singh, Pallab K; Meaney, David F

    2014-03-19

    Alterations in the activity of neural circuits are a common consequence of traumatic brain injury (TBI), but the relationship between single-neuron properties and the aggregate network behavior is not well understood. We recently reported that the GluN2B-containing NMDA receptors (NMDARs) are key in mediating mechanical forces during TBI, and that TBI produces a complex change in the functional connectivity of neuronal networks. Here, we evaluated whether cell-to-cell heterogeneity in the connectivity and aggregate contribution of GluN2B receptors to [Ca(2+)]i before injury influenced the functional rewiring, spontaneous activity, and network plasticity following injury using primary rat cortical dissociated neurons. We found that the functional connectivity of a neuron to its neighbors, combined with the relative influx of calcium through distinct NMDAR subtypes, together contributed to the individual neuronal response to trauma. Specifically, individual neurons whose [Ca(2+)]i oscillations were largely due to GluN2B NMDAR activation lost many of their functional targets 1 h following injury. In comparison, neurons with large GluN2A contribution or neurons with high functional connectivity both independently protected against injury-induced loss in connectivity. Mechanistically, we found that traumatic injury resulted in increased uncorrelated network activity, an effect linked to reduction of the voltage-sensitive Mg(2+) block of GluN2B-containing NMDARs. This uncorrelated activation of GluN2B subtypes after injury significantly limited the potential for network remodeling in response to a plasticity stimulus. Together, our data suggest that two single-cell characteristics, the aggregate contribution of NMDAR subtypes and the number of functional connections, influence network structure following traumatic injury.

  15. Neuromorphic Silicon Neuron Circuits

    Science.gov (United States)

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; van Schaik, André; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain–machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance-based Hodgkin–Huxley models to bi-dimensional generalized adaptive integrate and fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips. PMID:21747754

  16. Neuromorphic Silicon Neuron Circuits

    National Research Council Canada - National Science Library

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; Schaik, André van; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems...

  17. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri

    2011-05-01

    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  18. Histamine Transmission Modulates the Phenotype of Murine Narcolepsy Caused by Orexin Neuron Deficiency.

    Science.gov (United States)

    Bastianini, Stefano; Silvani, Alessandro; Berteotti, Chiara; Lo Martire, Viviana; Cohen, Gary; Ohtsu, Hiroshi; Lin, Jian-Sheng; Zoccoli, Giovanna

    2015-01-01

    Narcolepsy type 1 is associated with loss of orexin neurons, sleep-wake derangements, cataplexy, and a wide spectrum of alterations in other physiological functions, including energy balance, cardiovascular, and respiratory control. It is unclear which narcolepsy signs are directly related to the lack of orexin neurons or are instead modulated by dysfunction of other neurotransmitter systems physiologically controlled by orexin neurons, such as the histamine system. To address this question, we tested whether some of narcolepsy signs would be detected in mice lacking histamine signaling (HDC-KO). Moreover, we studied double-mutant mice lacking both histamine signaling and orexin neurons (DM) to evaluate whether the absence of histamine signaling would modulate narcolepsy symptoms produced by orexin deficiency. Mice were instrumented with electrodes for recording the electroencephalogram and electromyogram and a telemetric arterial pressure transducer. Sleep attacks fragmenting wakefulness, cataplexy, excess rapid-eye-movement sleep (R) during the activity period, and enhanced increase of arterial pressure during R, which are hallmarks of narcolepsy in mice, did not occur in HDC-KO, whereas they were observed in DM mice. Thus, these narcolepsy signs are neither caused nor abrogated by the absence of histamine. Conversely, the lack of histamine produced obesity in HDC-KO and to a greater extent also in DM. Moreover, the regularity of breath duration during R was significantly increased in either HDC-KO or DM relative to that in congenic wild-type mice. Defects of histamine transmission may thus modulate the metabolic and respiratory phenotype of murine narcolepsy.

  19. Histamine Transmission Modulates the Phenotype of Murine Narcolepsy Caused by Orexin Neuron Deficiency.

    Directory of Open Access Journals (Sweden)

    Stefano Bastianini

    Full Text Available Narcolepsy type 1 is associated with loss of orexin neurons, sleep-wake derangements, cataplexy, and a wide spectrum of alterations in other physiological functions, including energy balance, cardiovascular, and respiratory control. It is unclear which narcolepsy signs are directly related to the lack of orexin neurons or are instead modulated by dysfunction of other neurotransmitter systems physiologically controlled by orexin neurons, such as the histamine system. To address this question, we tested whether some of narcolepsy signs would be detected in mice lacking histamine signaling (HDC-KO. Moreover, we studied double-mutant mice lacking both histamine signaling and orexin neurons (DM to evaluate whether the absence of histamine signaling would modulate narcolepsy symptoms produced by orexin deficiency. Mice were instrumented with electrodes for recording the electroencephalogram and electromyogram and a telemetric arterial pressure transducer. Sleep attacks fragmenting wakefulness, cataplexy, excess rapid-eye-movement sleep (R during the activity period, and enhanced increase of arterial pressure during R, which are hallmarks of narcolepsy in mice, did not occur in HDC-KO, whereas they were observed in DM mice. Thus, these narcolepsy signs are neither caused nor abrogated by the absence of histamine. Conversely, the lack of histamine produced obesity in HDC-KO and to a greater extent also in DM. Moreover, the regularity of breath duration during R was significantly increased in either HDC-KO or DM relative to that in congenic wild-type mice. Defects of histamine transmission may thus modulate the metabolic and respiratory phenotype of murine narcolepsy.

  20. State-dependency of neuronal slow dynamics during sleep observed in cat lateral geniculate nucleus.

    Science.gov (United States)

    Nakamura, K; Yamamoto, M; Takahashi, K; Nakao, M; Mizutani, Y; Katayama, N; Kodama, T

    2000-01-01

    From the accumulated results, we hypothesize that neurons in the central processor systems of the brain generally exhibit a common state-dependency in slow dynamics of their spontaneous activities during sleep. In this paper, activities of relay cells in the cat's lateral geniculate nucleus (LGN) were studied to see if our hypothesis can be applied in this thalamic region. Data segments in polygraphically steady states were strictly extracted in order to sample the activities whose stationarity was guaranteed in a statistical sense. During slow wave sleep (SWS), the discharge pattern was characterized by short bursts. In contrast, the rather tonic discharge pattern was observed to prevail during rapid eye movement (REM) sleep. Spectral analyses showed white noise-like spectra in the low frequency range of 0.04-1.0 Hz during SWS, and 1/f noise-like spectra in the same frequency range during REM sleep. This state-dependency of the slow dynamics was consistently characterized by the other statistical parameters concerning the second-order moment as well. In contrast, the fast dynamics over 1.0 Hz tended to exhibit neuron-specific changes associated with the sleep state in terms of the Markovian dependency analysis. Consequently, our working hypothesis was not rejected for the LGN relay cells. The result here extends the possibility that the state-dependency of the slow dynamics we found is a general rule concerning single neuronal dynamics in widespread areas of the brain during sleep. The state-dependency of the slow dynamics of the LGN relay cells could be understood according to the proposed mechanism that a state-associated alteration in the global biasing input to a neural network during sleep induces the phenomenon with which we are concerned. The slow dynamics of neuronal activities might provide a novel framework defining SWS and REM sleep states instead of the polygraphic characteristics.

  1. Performance limitations of relay neurons.

    Directory of Open Access Journals (Sweden)

    Rahul Agarwal

    Full Text Available Relay cells are prevalent throughout sensory systems and receive two types of inputs: driving and modulating. The driving input contains receptive field properties that must be transmitted while the modulating input alters the specifics of transmission. For example, the visual thalamus contains relay neurons that receive driving inputs from the retina that encode a visual image, and modulating inputs from reticular activating system and layer 6 of visual cortex that control what aspects of the image will be relayed back to visual cortex for perception. What gets relayed depends on several factors such as attentional demands and a subject's goals. In this paper, we analyze a biophysical based model of a relay cell and use systems theoretic tools to construct analytic bounds on how well the cell transmits a driving input as a function of the neuron's electrophysiological properties, the modulating input, and the driving signal parameters. We assume that the modulating input belongs to a class of sinusoidal signals and that the driving input is an irregular train of pulses with inter-pulse intervals obeying an exponential distribution. Our analysis applies to any [Formula: see text] order model as long as the neuron does not spike without a driving input pulse and exhibits a refractory period. Our bounds on relay reliability contain performance obtained through simulation of a second and third order model, and suggest, for instance, that if the frequency of the modulating input increases or the DC offset decreases, then relay increases. Our analysis also shows, for the first time, how the biophysical properties of the neuron (e.g. ion channel dynamics define the oscillatory patterns needed in the modulating input for appropriately timed relay of sensory information. In our discussion, we describe how our bounds predict experimentally observed neural activity in the basal ganglia in (i health, (ii in Parkinson's disease (PD, and (iii in PD during

  2. Lumping Izhikevich neurons

    OpenAIRE

    Visser Sid; van Gils Stephan A

    2014-01-01

    We present the construction of a planar vector field that yields the firing rate of a bursting Izhikevich neuron can be read out, while leaving the sub-threshold behaviour intact. This planar vector field is used to derive lumped formulations of two complex heterogeneous networks of bursting Izhikevich neurons. In both cases, the lumped model is compared with the spiking network. There is excellent agreement in terms of duration and number of action potentials within the bursts, but there is ...

  3. Effects of Hallucinogens on Neuronal Activity.

    Science.gov (United States)

    Lladó-Pelfort, L; Celada, P; Riga, M S; Troyano-Rodríguez, E; Santana, N; Artigas, F

    2017-02-26

    Hallucinogens evoke sensory, perceptual, affective, and cognitive effects that may be useful to understand the neurobiological basis of mood and psychotic disorders. The present chapter reviews preclinical research carried out in recent years in order to better understand the action of psychotomimetic agents such as the noncompetitive NMDA receptor (NMDA-R) antagonists and serotonergic hallucinogens. Our studies have focused on the mechanisms through which these agents alter cortical activity. Noncompetitive NMDA-R antagonists, such as phencyclidine (PCP) and MK-801 (dizocilpine), as well as the serotonergic hallucinogens DOI and 5-MeO-DMT, produce similar effects on cellular and population activity in prefrontal cortex (PFC); these effects include alterations of pyramidal neuron discharge (with an overall increase in firing), as well as a marked attenuation of the low frequency oscillations (0.2-4 Hz) to which neuronal discharge is coupled in anesthetized rodents. PCP increases c-fos expression in excitatory neurons from various cortical and subcortical areas, particularly the thalamus. This effect of PCP involves the preferential blockade of NMDA-R on GABAergic neurons of the reticular nucleus of the thalamus, which provides feedforward inhibition to the rest of thalamic nuclei. It is still unknown whether serotonergic hallucinogens also affect thalamocortical networks. However, when examined, similar alterations in other cortical areas, such as the primary visual cortex (V1), have been observed, suggesting that these agents affect cortical activity in sensory and associative areas. Interestingly, the disruption of PFC activity induced by PCP, DOI and 5-MeO-DMT is reversed by classical and atypical antipsychotic drugs. This effect suggests a possible link between the mechanisms underlying the disruption of perception by multiple classes of hallucinogenic agents and the therapeutic efficacy of antipsychotic agents.

  4. NeuronBank: A Tool for Cataloging Neuronal Circuitry

    Science.gov (United States)

    Katz, Paul S.; Calin-Jageman, Robert; Dhawan, Akshaye; Frederick, Chad; Guo, Shuman; Dissanayaka, Rasanjalee; Hiremath, Naveen; Ma, Wenjun; Shen, Xiuyn; Wang, Hsui C.; Yang, Hong; Prasad, Sushil; Sunderraman, Rajshekhar; Zhu, Ying

    2010-01-01

    The basic unit of any nervous system is the neuron. Therefore, understanding the operation of nervous systems ultimately requires an inventory of their constituent neurons and synaptic connectivity, which form neural circuits. The presence of uniquely identifiable neurons or classes of neurons in many invertebrates has facilitated the construction of cellular-level connectivity diagrams that can be generalized across individuals within a species. Homologous neurons can also be recognized across species. Here we describe NeuronBank.org, a web-based tool that we are developing for cataloging, searching, and analyzing neuronal circuitry within and across species. Information from a single species is represented in an individual branch of NeuronBank. Users can search within a branch or perform queries across branches to look for similarities in neuronal circuits across species. The branches allow for an extensible ontology so that additional characteristics can be added as knowledge grows. Each entry in NeuronBank generates a unique accession ID, allowing it to be easily cited. There is also an automatic link to a Wiki page allowing an encyclopedic explanation of the entry. All of the 44 previously published neurons plus one previously unpublished neuron from the mollusc, Tritonia diomedea, have been entered into a branch of NeuronBank as have 4 previously published neurons from the mollusc, Melibe leonina. The ability to organize information about neuronal circuits will make this information more accessible, ultimately aiding research on these important models. PMID:20428500

  5. Sensorimotor training alters action understanding.

    Science.gov (United States)

    Catmur, Caroline; Thompson, Emma L; Bairaktari, Orianna; Lind, Frida; Bird, Geoffrey

    2017-11-02

    The discovery of 'mirror' neurons stimulated intense interest in the role of motor processes in social interaction. A popular assumption is that observation-related motor activation, exemplified by mirror neurons' matching properties, evolved to subserve the 'understanding' of others' actions. Alternatively, such motor activation may result from sensorimotor learning. Sensorimotor training alters observation-related motor activation, but studies demonstrating training-dependent changes in motor activation have not addressed the functional role of such activation. We therefore tested whether sensorimotor learning alters action understanding. Participants completed an action understanding task, judging the weight of boxes lifted by another person, before and after 'counter-mirror' sensorimotor training. During this training they lifted heavy boxes while observing light boxes being lifted, and vice-versa. Compared to a control group, this training significantly reduced participants' action understanding ability. Performance on a duration judgement task was unaffected by training. These data suggest the ability to understand others' actions results from sensorimotor learning. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Glial cell-line derived neurotrophic factor-dependent fusimotor neuron survival during development.

    Science.gov (United States)

    Whitehead, Jennifer; Keller-Peck, Cynthia; Kucera, Jan; Tourtellotte, Warren G

    2005-01-01

    Glial cell-line derived neurotrophic factor (GDNF) is a potent survival factor for motor neurons. Previous studies have shown that some motor neurons depend upon GDNF during development but this GDNF-dependent motor neuron subpopulation has not been characterized. We examined GDNF expression patterns in muscle and the impact of altered GDNF expression on the development of subtypes of motor neurons. In GDNF hemizygous mice, motor neuron innervation to muscle spindle stretch receptors (fusimotor neuron innervation) was decreased, whereas in transgenic mice that overexpress GDNF in muscle, fusimotor innervation to muscle spindles was increased. Facial motor neurons, which do not contain fusimotor neurons, were not changed in number when GDNF was over expressed by facial muscles during their development. Taken together, these data indicate that fusimotor neurons depend upon GDNF for survival during development. Since the fraction of cervical and lumbar motor neurons lost in GDNF-deficient mice at birth closely approximates the size of the fusimotor neuron pool, these data suggest that motor neuron loss in GDNF-deficient mice may be primarily of fusimotor neuron origin.

  7. Overnight fasting regulates inhibitory tone to cholinergic neurons of the dorsomedial nucleus of the hypothalamus.

    Science.gov (United States)

    Groessl, Florian; Jeong, Jae Hoon; Talmage, David A; Role, Lorna W; Jo, Young-Hwan

    2013-01-01

    The dorsomedial nucleus of the hypothalamus (DMH) contributes to the regulation of overall energy homeostasis by modulating energy intake as well as energy expenditure. Despite the importance of the DMH in the control of energy balance, DMH-specific genetic markers or neuronal subtypes are poorly defined. Here we demonstrate the presence of cholinergic neurons in the DMH using genetically modified mice that express enhanced green florescent protein (eGFP) selectively in choline acetyltransferase (Chat)-neurons. Overnight food deprivation increases the activity of DMH cholinergic neurons, as shown by induction of fos protein and a significant shift in the baseline resting membrane potential. DMH cholinergic neurons receive both glutamatergic and GABAergic synaptic input, but the activation of these neurons by an overnight fast is due entirely to decreased inhibitory tone. The decreased inhibition is associated with decreased frequency and amplitude of GABAergic synaptic currents in the cholinergic DMH neurons, while glutamatergic synaptic transmission is not altered. As neither the frequency nor amplitude of miniature GABAergic or glutamatergic postsynaptic currents is affected by overnight food deprivation, the fasting-induced decrease in inhibitory tone to cholinergic neurons is dependent on superthreshold activity of GABAergic inputs. This study reveals that cholinergic neurons in the DMH readily sense the availability of nutrients and respond to overnight fasting via decreased GABAergic inhibitory tone. As such, altered synaptic as well as neuronal activity of DMH cholinergic neurons may play a critical role in the regulation of overall energy homeostasis.

  8. Overnight fasting regulates inhibitory tone to cholinergic neurons of the dorsomedial nucleus of the hypothalamus.

    Directory of Open Access Journals (Sweden)

    Florian Groessl

    Full Text Available The dorsomedial nucleus of the hypothalamus (DMH contributes to the regulation of overall energy homeostasis by modulating energy intake as well as energy expenditure. Despite the importance of the DMH in the control of energy balance, DMH-specific genetic markers or neuronal subtypes are poorly defined. Here we demonstrate the presence of cholinergic neurons in the DMH using genetically modified mice that express enhanced green florescent protein (eGFP selectively in choline acetyltransferase (Chat-neurons. Overnight food deprivation increases the activity of DMH cholinergic neurons, as shown by induction of fos protein and a significant shift in the baseline resting membrane potential. DMH cholinergic neurons receive both glutamatergic and GABAergic synaptic input, but the activation of these neurons by an overnight fast is due entirely to decreased inhibitory tone. The decreased inhibition is associated with decreased frequency and amplitude of GABAergic synaptic currents in the cholinergic DMH neurons, while glutamatergic synaptic transmission is not altered. As neither the frequency nor amplitude of miniature GABAergic or glutamatergic postsynaptic currents is affected by overnight food deprivation, the fasting-induced decrease in inhibitory tone to cholinergic neurons is dependent on superthreshold activity of GABAergic inputs. This study reveals that cholinergic neurons in the DMH readily sense the availability of nutrients and respond to overnight fasting via decreased GABAergic inhibitory tone. As such, altered synaptic as well as neuronal activity of DMH cholinergic neurons may play a critical role in the regulation of overall energy homeostasis.

  9. Neuronal avalanches and learning

    Energy Technology Data Exchange (ETDEWEB)

    Arcangelis, Lucilla de, E-mail: dearcangelis@na.infn.it [Department of Information Engineering and CNISM, Second University of Naples, 81031 Aversa (Italy)

    2011-05-01

    Networks of living neurons represent one of the most fascinating systems of biology. If the physical and chemical mechanisms at the basis of the functioning of a single neuron are quite well understood, the collective behaviour of a system of many neurons is an extremely intriguing subject. Crucial ingredient of this complex behaviour is the plasticity property of the network, namely the capacity to adapt and evolve depending on the level of activity. This plastic ability is believed, nowadays, to be at the basis of learning and memory in real brains. Spontaneous neuronal activity has recently shown features in common to other complex systems. Experimental data have, in fact, shown that electrical information propagates in a cortex slice via an avalanche mode. These avalanches are characterized by a power law distribution for the size and duration, features found in other problems in the context of the physics of complex systems and successful models have been developed to describe their behaviour. In this contribution we discuss a statistical mechanical model for the complex activity in a neuronal network. The model implements the main physiological properties of living neurons and is able to reproduce recent experimental results. Then, we discuss the learning abilities of this neuronal network. Learning occurs via plastic adaptation of synaptic strengths by a non-uniform negative feedback mechanism. The system is able to learn all the tested rules, in particular the exclusive OR (XOR) and a random rule with three inputs. The learning dynamics exhibits universal features as function of the strength of plastic adaptation. Any rule could be learned provided that the plastic adaptation is sufficiently slow.

  10. Multifaceted effects of oligodendroglial exosomes on neurons: impact on neuronal firing rate, signal transduction and gene regulation.

    Science.gov (United States)

    Fröhlich, Dominik; Kuo, Wen Ping; Frühbeis, Carsten; Sun, Jyh-Jang; Zehendner, Christoph M; Luhmann, Heiko J; Pinto, Sheena; Toedling, Joern; Trotter, Jacqueline; Krämer-Albers, Eva-Maria

    2014-09-26

    Exosomes are small membranous vesicles of endocytic origin that are released by almost every cell type. They exert versatile functions in intercellular communication important for many physiological and pathological processes. Recently, exosomes attracted interest with regard to their role in cell-cell communication in the nervous system. We have shown that exosomes released from oligodendrocytes upon stimulation with the neurotransmitter glutamate are internalized by neurons and enhance the neuronal stress tolerance. Here, we demonstrate that oligodendroglial exosomes also promote neuronal survival during oxygen-glucose deprivation, a model of cerebral ischaemia. We show the transfer from oligodendrocytes to neurons of superoxide dismutase and catalase, enzymes which are known to help cells to resist oxidative stress. Additionally, we identify various effects of oligodendroglial exosomes on neuronal physiology. Electrophysiological analysis using in vitro multi-electrode arrays revealed an increased firing rate of neurons exposed to oligodendroglial exosomes. Moreover, gene expression analysis and phosphorylation arrays uncovered differentially expressed genes and altered signal transduction pathways in neurons after exosome treatment. Our study thus provides new insight into the broad spectrum of action of oligodendroglial exosomes and their effects on neuronal physiology. The exchange of extracellular vesicles between neural cells may exhibit remarkable potential to impact brain performance. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  11. The Languages of Neurons: An Analysis of Coding Mechanisms by Which Neurons Communicate, Learn and Store Information

    Directory of Open Access Journals (Sweden)

    Morris H. Baslow

    2009-11-01

    Full Text Available In this paper evidence is provided that individual neurons possess language, and that the basic unit for communication consists of two neurons and their entire field of interacting dendritic and synaptic connections. While information processing in the brain is highly complex, each neuron uses a simple mechanism for transmitting information. This is in the form of temporal electrophysiological action potentials or spikes (S operating on a millisecond timescale that, along with pauses (P between spikes constitute a two letter “alphabet” that generates meaningful frequency-encoded signals or neuronal S/P “words” in a primary language. However, when a word from an afferent neuron enters the dendritic-synaptic-dendritic field between two neurons, it is translated into a new frequency-encoded word with the same meaning, but in a different spike-pause language, that is delivered to and understood by the efferent neuron. It is suggested that this unidirectional inter-neuronal language-based word translation step is of utmost importance to brain function in that it allows for variations in meaning to occur. Thus, structural or biochemical changes in dendrites or synapses can produce novel words in the second language that have changed meanings, allowing for a specific signaling experience, either external or internal, to modify the meaning of an original word (learning, and store the learned information of that experience (memory in the form of an altered dendritic-synaptic-dendritic field.

  12. Activation of neuronal P2X7 receptor-pannexin-1 mediates death of enteric neurons during colitis.

    Science.gov (United States)

    Gulbransen, Brian D; Bashashati, Mohammad; Hirota, Simon A; Gui, Xianyong; Roberts, Jane A; MacDonald, Justin A; Muruve, Daniel A; McKay, Derek M; Beck, Paul L; Mawe, Gary M; Thompson, Roger J; Sharkey, Keith A

    2012-03-18

    Inflammatory bowel diseases (IBDs) are chronic relapsing and remitting conditions associated with long-term gut dysfunction resulting from alterations to the enteric nervous system and a loss of enteric neurons. The mechanisms underlying inflammation-induced enteric neuron death are unknown. Here using in vivo models of experimental colitis we report that inflammation causes enteric neuron death by activating a neuronal signaling complex composed of P2X7 receptors (P2X7Rs), pannexin-1 (Panx1) channels, the Asc adaptor protein and caspases. Inhibition of P2X7R, Panx1, Asc or caspase activity prevented inflammation-induced neuron cell death. Preservation of enteric neurons by inhibiting Panx1 in vivo prevented the onset of inflammation-induced colonic motor dysfunction. Panx1 expression was reduced in Crohn's disease but not ulcerative colitis. We conclude that activation of neuronal Panx1 underlies neuron death and the subsequent development of abnormal gut motility in IBD. Targeting Panx1 represents a new neuroprotective strategy to ameliorate the progression of IBD-associated dysmotility.

  13. Developmental switch of leptin signaling in arcuate nucleus neurons.

    Science.gov (United States)

    Baquero, Arian F; de Solis, Alain J; Lindsley, Sarah R; Kirigiti, Melissa A; Smith, M Susan; Cowley, Michael A; Zeltser, Lori M; Grove, Kevin L

    2014-07-23

    Leptin is well known for its role in the regulation of energy homeostasis in adults, a mechanism that at least partially results from the inhibition of the activity of NPY/AgRP/GABA neurons (NAG) in the arcuate nucleus of the hypothalamus (ARH). During early postnatal development in the rodent, leptin promotes axonal outgrowth from ARH neurons, and preautonomic NAG neurons are particularly responsive to leptin's trophic effects. To begin to understand how leptin could simultaneously promote axonal outgrowth from and inhibit the activity of NAG neurons, we characterized the electrochemical effects of leptin on NAG neurons in mice during early development. Here, we show that NAG neurons do indeed express a functional leptin receptor throughout the early postnatal period in the mouse; however, at postnatal days 13-15, leptin causes membrane depolarization in NAG neurons, rather than the expected hyperpolarization. Leptin action on NAG neurons transitions from stimulatory to inhibitory in the periweaning period, in parallel with the acquisition of functional ATP-sensitive potassium channels. These findings are consistent with the idea that leptin provides an orexigenic drive through the NAG system to help rapidly growing pups meet their energy requirements. Copyright © 2014 the authors 0270-6474/14/349982-13$15.00/0.

  14. Vagal Sensory Neuron Subtypes that Differentially Control Breathing.

    Science.gov (United States)

    Chang, Rui B; Strochlic, David E; Williams, Erika K; Umans, Benjamin D; Liberles, Stephen D

    2015-04-23

    Breathing is essential for survival and under precise neural control. The vagus nerve is a major conduit between lung and brain required for normal respiration. Here, we identify two populations of mouse vagus nerve afferents (P2ry1, Npy2r), each a few hundred neurons, that exert powerful and opposing effects on breathing. Genetically guided anatomical mapping revealed that these neurons densely innervate the lung and send long-range projections to different brainstem targets. Npy2r neurons are largely slow-conducting C fibers, while P2ry1 neurons are largely fast-conducting A fibers that contact pulmonary endocrine cells (neuroepithelial bodies). Optogenetic stimulation of P2ry1 neurons acutely silences respiration, trapping animals in exhalation, while stimulating Npy2r neurons causes rapid, shallow breathing. Activating P2ry1 neurons did not impact heart rate or gastric pressure, other autonomic functions under vagal control. Thus, the vagus nerve contains intermingled sensory neurons constituting genetically definable labeled lines with different anatomical connections and physiological roles. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Selective conversion of fibroblasts into peripheral sensory neurons.

    Science.gov (United States)

    Blanchard, Joel W; Eade, Kevin T; Szűcs, Attila; Lo Sardo, Valentina; Tsunemoto, Rachel K; Williams, Daniel; Sanna, Pietro Paolo; Baldwin, Kristin K

    2015-01-01

    Humans and mice detect pain, itch, temperature, pressure, stretch and limb position via signaling from peripheral sensory neurons. These neurons are divided into three functional classes (nociceptors/pruritoceptors, mechanoreceptors and proprioceptors) that are distinguished by their selective expression of TrkA, TrkB or TrkC receptors, respectively. We found that transiently coexpressing Brn3a with either Ngn1 or Ngn2 selectively reprogrammed human and mouse fibroblasts to acquire key properties of these three classes of sensory neurons. These induced sensory neurons (iSNs) were electrically active, exhibited distinct sensory neuron morphologies and matched the characteristic gene expression patterns of endogenous sensory neurons, including selective expression of Trk receptors. In addition, we found that calcium-imaging assays could identify subsets of iSNs that selectively responded to diverse ligands known to activate itch- and pain-sensing neurons. These results offer a simple and rapid means for producing genetically diverse human sensory neurons suitable for drug screening and mechanistic studies.

  16. Adhesion to carbon nanotube conductive scaffolds forces action-potential appearance in immature rat spinal neurons

    OpenAIRE

    Alessandra Fabbro; Antonietta Sucapane; Francesca Maria Toma; Enrica Calura; Lisa Rizzetto; Claudia Carrieri; Paola Roncaglia; Valentina Martinelli; Denis Scaini; Lara Masten; Antonio Turco; Stefano Gustincich; Maurizio Prato; Laura Ballerini

    2013-01-01

    In the last decade, carbon nanotube growth substrates have been used to investigate neurons and neuronal networks formation in vitro when guided by artificial nano-scaled cues. Besides, nanotube-based interfaces are being developed, such as prosthesis for monitoring brain activity. We recently described how carbon nanotube substrates alter the electrophysiological and synaptic responses of hippocampal neurons in culture. This observation highlighted the exceptional ability of this material in...

  17. Amyloid Precursor Proteins Are Dynamically Trafficked and Processed During Neuronal Development

    Directory of Open Access Journals (Sweden)

    Jenna M. Ramaker

    2016-11-01

    Full Text Available Proteolytic processing of the Amyloid Precursor Protein (APP produces beta-amyloid (Aβ peptide fragments that accumulate in Alzheimer’s Disease (AD, but APP may also regulate multiple aspects of neuronal development, albeit via mechanisms that are not well understood. APP is a member of a family of transmembrane glycoproteins expressed by all higher organisms, including two mammalian orthologs (APLP1 and APLP2 that have complicated investigations into the specific activities of APP. By comparison, insects express only a single APP-related protein (APP-Like, or APPL that contains the same protein interaction domains identified in APP. However, unlike its mammalian orthologs, APPL is only expressed by neurons, greatly simplifying an analysis of its functions in vivo. Like APP, APPL is processed by secretases to generate a similar array of extracellular and intracellular cleavage fragments, as well as an Aβ-like fragment that can induce neurotoxic responses in the brain. Exploiting the complementary advantages of two insect models (Drosophila melanogaster and Manduca sexta, we have investigated the regulation of APPL trafficking and processing with respect to different aspects of neuronal development. By comparing the behavior of endogenously expressed APPL with fluorescently tagged versions of APPL and APP, we have shown that some full-length protein is consistently trafficked into the most motile regions of developing neurons both in vitro and in vivo. Concurrently, much of the holoprotein is rapidly processed into N- and C-terminal fragments that undergo bi-directional transport within distinct vesicle populations. Unexpectedly, we also discovered that APPL can be transiently sequestered into an amphisome-like compartment in developing neurons, while manipulations targeting APPL cleavage altered their motile behavior in cultured embryos. These data suggest that multiple mechanisms restrict the bioavailability of the holoprotein to regulate

  18. Histamine Transmission Modulates the Phenotype of Murine Narcolepsy Caused by Orexin Neuron Deficiency

    National Research Council Canada - National Science Library

    Bastianini, Stefano; Silvani, Alessandro; Berteotti, Chiara; Lo Martire, Viviana; Cohen, Gary; Ohtsu, Hiroshi; Lin, Jian-Sheng; Zoccoli, Giovanna

    2015-01-01

    Narcolepsy type 1 is associated with loss of orexin neurons, sleep-wake derangements, cataplexy, and a wide spectrum of alterations in other physiological functions, including energy balance, cardio...

  19. Domoic acid disrupts the activity and connectivity of neuronal networks in organotypic brain slice cultures.

    Science.gov (United States)

    Hiolski, E M; Ito, S; Beggs, J M; Lefebvre, K A; Litke, A M; Smith, D R

    2016-09-01

    Domoic acid is a neurotoxin produced by algae and is found in seafood during harmful algal blooms. As a glutamate agonist, domoic acid inappropriately stimulates excitatory activity in neurons. At high doses, this leads to seizures and brain lesions, but it is unclear how lower, asymptomatic exposures disrupt neuronal activity. Domoic acid has been detected in an increasing variety of species across a greater geographical range than ever before, making it critical to understand the potential health impacts of low-level exposure on vulnerable marine mammal and human populations. To determine whether prolonged domoic acid exposure altered neuronal activity in hippocampal networks, we used a custom-made 512 multi-electrode array with high spatial and temporal resolution to record extracellular potentials (spikes) in mouse organotypic brain slice cultures. We identified individual neurons based on spike waveform and location, and measured the activity and functional connectivity within the neuronal networks of brain slice cultures. Domoic acid exposure significantly altered neuronal spiking activity patterns, and increased functional connectivity within exposed cultures, in the absence of overt cellular or neuronal toxicity. While the overall spiking activity of neurons in domoic acid-exposed cultures was comparable to controls, exposed neurons spiked significantly more often in bursts. We also identified a subset of neurons that were electrophysiologically silenced in exposed cultures, and putatively identified those neurons as fast-spiking inhibitory neurons. These results provide evidence that domoic acid affects neuronal activity in the absence of cytotoxicity, and suggest that neurodevelopmental exposure to domoic acid may alter neurological function in the absence of clinical symptoms. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Neuronal spike initiation modulated by extracellular electric fields.

    Directory of Open Access Journals (Sweden)

    Guo-Sheng Yi

    Full Text Available Based on a reduced two-compartment model, the dynamical and biophysical mechanism underlying the spike initiation of the neuron to extracellular electric fields is investigated in this paper. With stability and phase plane analysis, we first investigate in detail the dynamical properties of neuronal spike initiation induced by geometric parameter and internal coupling conductance. The geometric parameter is the ratio between soma area and total membrane area, which describes the proportion of area occupied by somatic chamber. It is found that varying it could qualitatively alter the bifurcation structures of equilibrium as well as neuronal phase portraits, which remain unchanged when varying internal coupling conductance. By analyzing the activating properties of somatic membrane currents at subthreshold potentials, we explore the relevant biophysical basis of spike initiation dynamics induced by these two parameters. It is observed that increasing geometric parameter could greatly decrease the intensity of the internal current flowing from soma to dendrite, which switches spike initiation dynamics from Hopf bifurcation to SNIC bifurcation; increasing internal coupling conductance could lead to the increase of this outward internal current, whereas the increasing range is so small that it could not qualitatively alter the spike initiation dynamics. These results highlight that neuronal geometric parameter is a crucial factor in determining the spike initiation dynamics to electric fields. The finding is useful to interpret the functional significance of neuronal biophysical properties in their encoding dynamics, which could contribute to uncovering how neuron encodes electric field signals.

  1. Kappe neurons, a novel population of olfactory sensory neurons

    Science.gov (United States)

    Ahuja, Gaurav; Nia, Shahrzad Bozorg; Zapilko, Veronika; Shiriagin, Vladimir; Kowatschew, Daniel; Oka, Yuichiro; Korsching, Sigrun I.

    2014-02-01

    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons are identified by their Go-like immunoreactivity, and show a distinct spatial distribution within the olfactory epithelium, similar to, but significantly different from that of crypt neurons. Furthermore, kappe neurons project to a single identified target glomerulus within the olfactory bulb, mdg5 of the mediodorsal cluster, whereas crypt neurons are known to project exclusively to the mdg2 glomerulus. Kappe neurons are negative for established markers of ciliated, microvillous and crypt neurons, but appear to have microvilli. Kappe neurons constitute the fourth type of olfactory sensory neurons reported in teleost fishes and their existence suggests that encoding of olfactory stimuli may require a higher complexity than hitherto assumed already in the peripheral olfactory system.

  2. Lumping Izhikevich neurons

    Directory of Open Access Journals (Sweden)

    Visser Sid

    2014-12-01

    Full Text Available We present the construction of a planar vector field that yields the firing rate of a bursting Izhikevich neuron can be read out, while leaving the sub-threshold behavior intact. This planar vector field is used to derive lumped formulations of two complex heterogeneous networks of bursting Izhikevich neurons. In both cases, the lumped model is compared with the spiking network. There is excellent agreement in terms of duration and number of action potentials within the bursts, but there is a slight mismatch of the burst frequency. The lumped model accurately accounts for both intrinsic bursting and post inhibitory rebound potentials in the neuron model, features which are absent in prevalent neural mass models.

  3. Stochastic neuron models

    CERN Document Server

    Greenwood, Priscilla E

    2016-01-01

    This book describes a large number of open problems in the theory of stochastic neural systems, with the aim of enticing probabilists to work on them. This includes problems arising from stochastic models of individual neurons as well as those arising from stochastic models of the activities of small and large networks of interconnected neurons. The necessary neuroscience background to these problems is outlined within the text, so readers can grasp the context in which they arise. This book will be useful for graduate students and instructors providing material and references for applying probability to stochastic neuron modeling. Methods and results are presented, but the emphasis is on questions where additional stochastic analysis may contribute neuroscience insight. An extensive bibliography is included. Dr. Priscilla E. Greenwood is a Professor Emerita in the Department of Mathematics at the University of British Columbia. Dr. Lawrence M. Ward is a Professor in the Department of Psychology and the Brain...

  4. Imaging voltage in neurons

    Science.gov (United States)

    Peterka, Darcy S.; Takahashi, Hiroto; Yuste, Rafael

    2011-01-01

    In the last decades, imaging membrane potential has become a fruitful approach to study neural circuits, especially in invertebrate preparations with large, resilient neurons. At the same time, particularly in mammalian preparations, voltage imaging methods suffer from poor signal to noise and secondary side effects, and they fall short of providing single-cell resolution when imaging of the activity of neuronal populations. As an introduction to these techniques, we briefly review different voltage imaging methods (including organic fluorophores, SHG chromophores, genetic indicators, hybrid, nanoparticles and intrinsic approaches), and illustrate some of their applications to neuronal biophysics and mammalian circuit analysis. We discuss their mechanisms of voltage sensitivity, from reorientation, electrochromic or electro-optical phenomena, to interaction among chromophores or membrane scattering, and highlight their advantages and shortcomings, commenting on the outlook for development of novel voltage imaging methods. PMID:21220095

  5. Specific and rapid effects of acoustic stimulation on the tonotopic distribution of Kv3.1b potassium channels in the adult rat.

    Science.gov (United States)

    Strumbos, J G; Polley, D B; Kaczmarek, L K

    2010-05-19

    Recent studies have demonstrated that total cellular levels of voltage-gated potassium channel subunits can change on a time scale of minutes in acute slices and cultured neurons, raising the possibility that rapid changes in the abundance of channel proteins contribute to experience-dependent plasticity in vivo. In order to investigate this possibility, we took advantage of the medial nucleus of the trapezoid body (MNTB) sound localization circuit, which contains neurons that precisely phase-lock their action potentials to rapid temporal fluctuations in the acoustic waveform. Previous work has demonstrated that the ability of these neurons to follow high-frequency stimuli depends critically upon whether they express adequate amounts of the potassium channel subunit Kv3.1. To test the hypothesis that net amounts of Kv3.1 protein would be rapidly upregulated when animals are exposed to sounds that require high frequency firing for accurate encoding, we briefly exposed adult rats to acoustic environments that varied according to carrier frequency and amplitude modulation (AM) rate. Using an antibody directed at the cytoplasmic C-terminus of Kv3.1b (the adult splice isoform of Kv3.1), we found that total cellular levels of Kv3.1b protein-as well as the tonotopic distribution of Kv3.1b-labeled cells-was significantly altered following 30 min of exposure to rapidly modulated (400 Hz) sounds relative to slowly modulated (0-40 Hz, 60 Hz) sounds. These results provide direct evidence that net amounts of Kv3.1b protein can change on a time scale of minutes in response to stimulus-driven synaptic activity, permitting auditory neurons to actively adapt their complement of ion channels to changes in the acoustic environment. Copyright 2010 IBRO. Published by Elsevier Ltd. All rights reserved.

  6. Visualizing the spinal neuronal dynamics of locomotion

    Science.gov (United States)

    Subramanian, Kalpathi R.; Bashor, D. P.; Miller, M. T.; Foster, J. A.

    2004-06-01

    Modern imaging and simulation techniques have enhanced system-level understanding of neural function. In this article, we present an application of interactive visualization to understanding neuronal dynamics causing locomotion of a single hip joint, based on pattern generator output of the spinal cord. Our earlier work visualized cell-level responses of multiple neuronal populations. However, the spatial relationships were abstract, making communication with colleagues difficult. We propose two approaches to overcome this: (1) building a 3D anatomical model of the spinal cord with neurons distributed inside, animated by the simulation and (2) adding limb movements predicted by neuronal activity. The new system was tested using a cat walking central pattern generator driving a pair of opposed spinal motoneuron pools. Output of opposing motoneuron pools was combined into a single metric, called "Net Neural Drive", which generated angular limb movement in proportion to its magnitude. Net neural drive constitutes a new description of limb movement control. The combination of spatial and temporal information in the visualizations elegantly conveys the neural activity of the output elements (motoneurons), as well as the resulting movement. The new system encompasses five biological levels of organization from ion channels to observed behavior. The system is easily scalable, and provides an efficient interactive platform for rapid hypothesis testing.

  7. A novel, primate-specific, brain isoform of KCNH2 impacts cortical physiology, cognition, neuronal repolarization and risk for schizophrenia

    Science.gov (United States)

    Huffaker, Stephen J.; Chen, Jingshan; Nicodemus, Kristin K.; Sambataro, Fabio; Yang, Feng; Mattay, Venkata; Lipska, Barbara K.; Hyde, Thomas M.; Song, Jian; Rujescu, Daniel; Giegling, Ina; Mayilyan, Karine; Proust, Morgan J.; Soghoyan, Armen; Caforio, Grazia; Callicott, Joseph H.; Bertolino, Alessandro; Meyer-Lindenberg, Andreas; Chang, Jay; Ji, Yuanyuan; Egan, Michael F.; Goldberg, Terry E.; Kleinman, Joel E.; Lu, Bai; Weinberger, Daniel R.

    2009-01-01

    Organized neuronal firing is critical for cortical processing and is disrupted in schizophrenia. Using 5’ RACE in human brain, we identified a primate-specific isoform (3.1) of the K+-channel KCNH2 that modulates neuronal firing. KCNH2-3.1 mRNA levels are comparable to KCNH2-1A in brain, but 1000-fold lower in heart. In schizophrenic hippocampus, KCNH2-3.1 expression is 2.5-fold greater than KCNH2-1A. A meta-analysis of 5 clinical samples (367 families, 1158 unrelated cases, 1704 controls) shows association of SNPs in KCNH2 with schizophrenia. Risk-associated alleles predict lower IQ scores and speed of cognitive processing, altered memory-linked fMRI signals, and increased KCNH2-3.1 expression in post-mortem hippocampus. KCNH2-3.1 lacks a domain critical for slow channel deactivation. Overexpression of KCNH2-3.1 in primary cortical neurons induces a rapidly deactivating K+ current and a high-frequency, non-adapting firing pattern. These results identify a novel KCNH2 channel involved in cortical physiology, cognition, and psychosis, providing a potential new psychotherapeutic drug target. PMID:19412172

  8. Staurosporine and extracellular matrix proteins mediate the conversion of small cell lung carcinoma cells into a neuron-like phenotype.

    Directory of Open Access Journals (Sweden)

    Tamara Murmann

    Full Text Available Small cell lung carcinomas (SCLCs represent highly aggressive tumors with an overall five-year survival rate in the range of 5 to 10%. Here, we show that four out of five SCLC cell lines reversibly develop a neuron-like phenotype on extracellular matrix constituents such as fibronectin, laminin or thrombospondin upon staurosporine treatment in an RGD/integrin-mediated manner. Neurite-like processes extend rapidly with an average speed of 10 µm per hour. Depending on the cell line, staurosporine treatment affects either cell cycle arrest in G2/M phase or induction of polyploidy. Neuron-like conversion, although not accompanied by alterations in the expression pattern of a panel of neuroendocrine genes, leads to changes in protein expression as determined by two-dimensional gel electrophoresis. It is likely that SCLC cells already harbour the complete molecular repertoire to convert into a neuron-like phenotype. More extensive studies are needed to evaluate whether the conversion potential of SCLC cells is suitable for therapeutic interventions.

  9. 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.

  10. Photosensitive neurons in mollusks

    Directory of Open Access Journals (Sweden)

    Kartelija Gordana

    2005-01-01

    Full Text Available In addition to regular photoreceptors, some invertebrates possess simple extra ocular photoreceptors. For ex­ample, the central ganglia of mollusks contain photosensitive neurons. These neurons are located on the dorsal surface of the ganglia and based on their electrophysiological properties it has been postulated that they are internal photoreceptors. Besides the eye, transduction of light also occurs in these extra-ocular photoreceptors. In the present work, we analyze the reactivity of these nerve cells to light and describe the underlying mechanism mediating the light-induced response.

  11. From Neurons to Newtons

    DEFF Research Database (Denmark)

    Nielsen, Bjørn Gilbert

    2001-01-01

    proteins generate forces, to the macroscopic levels where overt arm movements are vol- untarily controlled within an unpredictable environment by legions of neurons¯ring in orderly fashion. An extensive computer simulation system has been developed for this thesis, which at present contains a neural...... network scripting language for specifying arbitrary neural architectures, de¯nition ¯les for detailed spinal networks, various biologically realistic models of neurons, and dynamic synapses. Also included are structurally accurate models of intrafusal and extra-fusal muscle ¯bers and a general body...

  12. Rapid neurogenesis through transcriptional activation in human stem cells.

    Science.gov (United States)

    Busskamp, Volker; Lewis, Nathan E; Guye, Patrick; Ng, Alex H M; Shipman, Seth L; Byrne, Susan M; Sanjana, Neville E; Murn, Jernej; Li, Yinqing; Li, Shangzhong; Stadler, Michael; Weiss, Ron; Church, George M

    2014-11-17

    Advances in cellular reprogramming and stem cell differentiation now enable ex vivo studies of human neuronal differentiation. However, it remains challenging to elucidate the underlying regulatory programs because differentiation protocols are laborious and often result in low neuron yields. Here, we overexpressed two Neurogenin transcription factors in human-induced pluripotent stem cells and obtained neurons with bipolar morphology in 4 days, at greater than 90% purity. The high purity enabled mRNA and microRNA expression profiling during neurogenesis, thus revealing the genetic programs involved in the rapid transition from stem cell to neuron. The resulting cells exhibited transcriptional, morphological and functional signatures of differentiated neurons, with greatest transcriptional similarity to prenatal human brain samples. Our analysis revealed a network of key transcription factors and microRNAs that promoted loss of pluripotency and rapid neurogenesis via progenitor states. Perturbations of key transcription factors affected homogeneity and phenotypic properties of the resulting neurons, suggesting that a systems-level view of the molecular biology of differentiation may guide subsequent manipulation of human stem cells to rapidly obtain diverse neuronal types. © 2014 The Authors. Published under the terms of the CC BY 4.0 license.

  13. Neuronal survival in the brain: neuron type-specific mechanisms

    DEFF Research Database (Denmark)

    Pfisterer, Ulrich Gottfried; Khodosevich, Konstantin

    2017-01-01

    numbers of neurons that are not yet completely integrated into the local circuits helps to ensure that maturation and homeostatic function of neuronal networks in the brain proceed correctly. External signals from brain microenvironment together with intrinsic signaling pathways determine whether......Neurogenic regions of mammalian brain produce many more neurons that will eventually survive and reach a mature stage. Developmental cell death affects both embryonically produced immature neurons and those immature neurons that are generated in regions of adult neurogenesis. Removal of substantial...... a particular neuron will die. To accommodate this signaling, immature neurons in the brain express a number of transmembrane factors as well as intracellular signaling molecules that will regulate the cell survival/death decision, and many of these factors cease being expressed upon neuronal maturation...

  14. Neuronal survival in the brain: neuron type-specific mechanisms

    DEFF Research Database (Denmark)

    Pfisterer, Ulrich Gottfried; Khodosevich, Konstantin

    2017-01-01

    Neurogenic regions of mammalian brain produce many more neurons that will eventually survive and reach a mature stage. Developmental cell death affects both embryonically produced immature neurons and those immature neurons that are generated in regions of adult neurogenesis. Removal of substantial...... numbers of neurons that are not yet completely integrated into the local circuits helps to ensure that maturation and homeostatic function of neuronal networks in the brain proceed correctly. External signals from brain microenvironment together with intrinsic signaling pathways determine whether...... a particular neuron will die. To accommodate this signaling, immature neurons in the brain express a number of transmembrane factors as well as intracellular signaling molecules that will regulate the cell survival/death decision, and many of these factors cease being expressed upon neuronal maturation...

  15. Control of REM sleep by ventral medulla GABAergic neurons.

    Science.gov (United States)

    Weber, Franz; Chung, Shinjae; Beier, Kevin T; Xu, Min; Luo, Liqun; Dan, Yang

    2015-10-15

    Rapid eye movement (REM) sleep is a distinct brain state characterized by activated electroencephalogram and complete skeletal muscle paralysis, and is associated with vivid dreams. Transection studies by Jouvet first demonstrated that the brainstem is both necessary and sufficient for REM sleep generation, and the neural circuits in the pons have since been studied extensively. The medulla also contains neurons that are active during REM sleep, but whether they play a causal role in REM sleep generation remains unclear. Here we show that a GABAergic (γ-aminobutyric-acid-releasing) pathway originating from the ventral medulla powerfully promotes REM sleep in mice. Optogenetic activation of ventral medulla GABAergic neurons rapidly and reliably initiated REM sleep episodes and prolonged their durations, whereas inactivating these neurons had the opposite effects. Optrode recordings from channelrhodopsin-2-tagged ventral medulla GABAergic neurons showed that they were most active during REM sleep (REMmax), and during wakefulness they were preferentially active during eating and grooming. Furthermore, dual retrograde tracing showed that the rostral projections to the pons and midbrain and caudal projections to the spinal cord originate from separate ventral medulla neuron populations. Activating the rostral GABAergic projections was sufficient for both the induction and maintenance of REM sleep, which are probably mediated in part by inhibition of REM-suppressing GABAergic neurons in the ventrolateral periaqueductal grey. These results identify a key component of the pontomedullary network controlling REM sleep. The capability to induce REM sleep on command may offer a powerful tool for investigating its functions.

  16. Effects of oxaliplatin on mouse myenteric neurons and colonic motility

    Directory of Open Access Journals (Sweden)

    Linah eWafai

    2013-03-01

    Full Text Available Oxaliplatin, an anti-cancer chemotherapeutic agent used for the treatment of colorectal cancer, commonly causes gastrointestinal side-effects such as constipation, diarrhoea, nausea and vomiting. Damage to enteric neurons may underlie some of these gastrointestinal side-effects, as the enteric nervous system controls the functions of the bowel. In this study, neuronal loss and changes to the structure and immunoreactivity of myenteric neuronal nitric oxide synthase (nNOS neurons were examined in colonic segments from mice following exposure to oxaliplatin ex vivo and following repeated intraperitoneal injections of oxaliplatin over 3 weeks in vivo, using immunohistochemistry and confocal microscopy. Significant morphological alterations and increases in the proportion of NOS-immunoreactive neurons were associated with both short-term oxaliplatin exposure and long-term oxaliplatin administration, confirming that oxaliplatin causes changes to the myenteric neurons. Long-term oxaliplatin administration induced substantial neuronal loss that was correlated with a reduction in both the frequency and propagation speed of colonic migrating motor complexes in vitro. Similar changes probably produce some symptoms experienced by patients undergoing oxaliplatin treatment.

  17. Lumping Izhikevich neurons

    NARCIS (Netherlands)

    Visser, S.; van Gils, Stephanus A.

    2014-01-01

    We present the construction of a planar vector field that yields the firing rate of a bursting Izhikevich neuron can be read out, while leaving the sub-threshold behaviour intact. This planar vector field is used to derive lumped formulations of two complex heterogeneous networks of bursting

  18. Retinoic acid affects calcium signaling in adult molluscan neurons

    Science.gov (United States)

    Vesprini, Nicholas D.; Dawson, Taylor F.; Yuan, Ye; Bruce, Doug

    2014-01-01

    Retinoic acid, the active metabolite of vitamin A, is important for nervous system development, regeneration, as well as cognitive functions of the adult central nervous system. These central nervous system functions are all highly dependent on neuronal activity. Retinoic acid has previously been shown to induce changes in the firing properties and action potential waveforms of adult molluscan neurons in a dose- and isomer-dependent manner. In this study, we aimed to determine the cellular pathways by which retinoic acid might exert such effects, by testing the involvement of pathways previously shown to be affected by retinoic acid. We demonstrated that the ability of all-trans retinoic acid (atRA) to induce electrophysiological changes in cultured molluscan neurons was not prevented by inhibitors of protein synthesis, protein kinase A or phospholipase C. However, we showed that atRA was capable of rapidly reducing intracellular calcium levels in the same dose- and isomer-dependent manner as shown previously for changes in neuronal firing. Moreover, we also demonstrated that the transmembrane ion flux through voltage-gated calcium channels was rapidly modulated by retinoic acid. In particular, the peak current density was reduced and the inactivation rate was increased in the presence of atRA, over a similar time course as the changes in cell firing and reductions in intracellular calcium. These studies provide further evidence for the ability of atRA to induce rapid effects in mature neurons. PMID:25343782

  19. Spiking neuron network Helmholtz machine

    National Research Council Canada - National Science Library

    Sountsov, Pavel; Miller, Paul

    2015-01-01

    .... This paper aims to unify the two fields of probabilistic inference and synaptic plasticity by using a neuronal network of realistic model spiking neurons to implement a well-studied computational...

  20. Identifying neuronal oscillations using rhythmicity

    NARCIS (Netherlands)

    Fransen, A.M.M.; Ede, F.L. van; Maris, E.G.G.

    2015-01-01

    Neuronal oscillations are a characteristic feature of neuronal activity and are typically investigated through measures of power and coherence. However, neither of these measures directly reflects the distinctive feature of oscillations: their rhythmicity. Rhythmicity is the extent to which future

  1. Somatostatin Neurons in the Basal Forebrain Promote High-Calorie Food Intake

    Directory of Open Access Journals (Sweden)

    Chen Zhu

    2017-07-01

    Full Text Available Obesity has become a global issue, and the overconsumption of food is thought to be a major contributor. However, the regulatory neural circuits that regulate palatable food consumption remain unclear. Here, we report that somatostatin (SOM neurons and GABAergic (VGAT neurons in the basal forebrain (BF play specific roles in regulating feeding. Optogenetic stimulation of BF SOM neurons increased fat and sucrose intake within minutes and promoted anxiety-like behaviors. Furthermore, optogenetic stimulation of projections from BF SOM neurons to the lateral hypothalamic area (LHA selectively resulted in fat intake. In addition, activation of BF VGAT neurons rapidly induced general food intake and gnawing behaviors. Whole-brain mapping of inputs and outputs showed that BF SOM neurons form bidirectional connections with several brain areas important in feeding and regulation of emotion. Collectively, these results suggest that BF SOM neurons play a selective role in hedonic feeding.

  2. Reelin secreted by GABAergic neurons regulates glutamate receptor homeostasis.

    Directory of Open Access Journals (Sweden)

    Cecilia Gonzalez Campo

    Full Text Available BACKGROUND: Reelin is a large secreted protein of the extracellular matrix that has been proposed to participate to the etiology of schizophrenia. During development, reelin is crucial for the correct cytoarchitecture of laminated brain structures and is produced by a subset of neurons named Cajal-Retzius. After birth, most of these cells degenerate and reelin expression persists in postnatal and adult brain. The phenotype of neurons that bind secreted reelin and whether the continuous secretion of reelin is required for physiological functions at postnatal stages remain unknown. METHODOLOGY/PRINCIPAL FINDINGS: Combining immunocytochemical and pharmacological approaches, we first report that two distinct patterns of reelin expression are present in cultured hippocampal neurons. We show that in hippocampal cultures, reelin is secreted by GABAergic neurons displaying an intense reelin immunoreactivity (IR. We demonstrate that secreted reelin binds to receptors of the lipoprotein family on neurons with a punctate reelin IR. Secondly, using calcium imaging techniques, we examined the physiological consequences of reelin secretion blockade. Blocking protein secretion rapidly and reversibly changes the subunit composition of N-methyl-D-aspartate glutamate receptors (NMDARs to a predominance of NR2B-containing NMDARs. Addition of recombinant or endogenously secreted reelin rescues the effects of protein secretion blockade and reverts the fraction of NR2B-containing NMDARs to control levels. Therefore, the continuous secretion of reelin is necessary to control the subunit composition of NMDARs in hippocampal neurons. CONCLUSIONS/SIGNIFICANCE: Our data show that the heterogeneity of reelin immunoreactivity correlates with distinct functional populations: neurons synthesizing and secreting reelin and/or neurons binding reelin. Furthermore, we show that continuous reelin secretion is a strict requirement to maintain the composition of NMDARs. We propose

  3. Localization of the brainstem GABAergic neurons controlling paradoxical (REM) sleep.

    Science.gov (United States)

    Sapin, Emilie; Lapray, Damien; Bérod, Anne; Goutagny, Romain; Léger, Lucienne; Ravassard, Pascal; Clément, Olivier; Hanriot, Lucie; Fort, Patrice; Luppi, Pierre-Hervé

    2009-01-01

    Paradoxical sleep (PS) is a state characterized by cortical activation, rapid eye movements and muscle atonia. Fifty years after its discovery, the neuronal network responsible for the genesis of PS has been only partially identified. We recently proposed that GABAergic neurons would have a pivotal role in that network. To localize these GABAergic neurons, we combined immunohistochemical detection of Fos with non-radioactive in situ hybridization of GAD67 mRNA (GABA synthesis enzyme) in control rats, rats deprived of PS for 72 h and rats allowed to recover after such deprivation. Here we show that GABAergic neurons gating PS (PS-off neurons) are principally located in the ventrolateral periaqueductal gray (vlPAG) and the dorsal part of the deep mesencephalic reticular nucleus immediately ventral to it (dDpMe). Furthermore, iontophoretic application of muscimol for 20 min in this area in head-restrained rats induced a strong and significant increase in PS quantities compared to saline. In addition, we found a large number of GABAergic PS-on neurons in the vlPAG/dDPMe region and the medullary reticular nuclei known to generate muscle atonia during PS. Finally, we showed that PS-on neurons triggering PS localized in the SLD are not GABAergic. Altogether, our results indicate that multiple populations of PS-on GABAergic neurons are distributed in the brainstem while only one population of PS-off GABAergic neurons localized in the vlPAG/dDpMe region exist. From these results, we propose a revised model for PS control in which GABAergic PS-on and PS-off neurons localized in the vlPAG/dDPMe region play leading roles.

  4. Localization of the brainstem GABAergic neurons controlling paradoxical (REM sleep.

    Directory of Open Access Journals (Sweden)

    Emilie Sapin

    Full Text Available Paradoxical sleep (PS is a state characterized by cortical activation, rapid eye movements and muscle atonia. Fifty years after its discovery, the neuronal network responsible for the genesis of PS has been only partially identified. We recently proposed that GABAergic neurons would have a pivotal role in that network. To localize these GABAergic neurons, we combined immunohistochemical detection of Fos with non-radioactive in situ hybridization of GAD67 mRNA (GABA synthesis enzyme in control rats, rats deprived of PS for 72 h and rats allowed to recover after such deprivation. Here we show that GABAergic neurons gating PS (PS-off neurons are principally located in the ventrolateral periaqueductal gray (vlPAG and the dorsal part of the deep mesencephalic reticular nucleus immediately ventral to it (dDpMe. Furthermore, iontophoretic application of muscimol for 20 min in this area in head-restrained rats induced a strong and significant increase in PS quantities compared to saline. In addition, we found a large number of GABAergic PS-on neurons in the vlPAG/dDPMe region and the medullary reticular nuclei known to generate muscle atonia during PS. Finally, we showed that PS-on neurons triggering PS localized in the SLD are not GABAergic. Altogether, our results indicate that multiple populations of PS-on GABAergic neurons are distributed in the brainstem while only one population of PS-off GABAergic neurons localized in the vlPAG/dDpMe region exist. From these results, we propose a revised model for PS control in which GABAergic PS-on and PS-off neurons localized in the vlPAG/dDPMe region play leading roles.

  5. Amyloid-Beta Induced Changes in Vesicular Transport of BDNF in Hippocampal Neurons

    Directory of Open Access Journals (Sweden)

    Bianca Seifert

    2016-01-01

    Full Text Available The neurotrophin brain derived neurotrophic factor (BDNF is an important growth factor in the CNS. Deficits in transport of this secretory protein could underlie neurodegenerative diseases. Investigation of disease-related changes in BDNF transport might provide insights into the cellular mechanism underlying, for example, Alzheimer’s disease (AD. To analyze the role of BDNF transport in AD, live cell imaging of fluorescently labeled BDNF was performed in hippocampal neurons of different AD model systems. BDNF and APP colocalized with low incidence in vesicular structures. Anterograde as well as retrograde transport of BDNF vesicles was reduced and these effects were mediated by factors released from hippocampal neurons into the extracellular medium. Transport of BDNF was altered at a very early time point after onset of human APP expression or after acute amyloid-beta(1-42 treatment, while the activity-dependent release of BDNF remained unaffected. Taken together, extracellular cleavage products of APP induced rapid changes in anterograde and retrograde transport of BDNF-containing vesicles while release of BDNF was unaffected by transgenic expression of mutated APP. These early transport deficits might lead to permanently impaired brain functions in the adult brain.

  6. Biosynthesis and processing of endogenous BDNF: CNS neurons store and secrete BDNF, not pro-BDNF.

    Science.gov (United States)

    Matsumoto, Tomoya; Rauskolb, Stefanie; Polack, Martin; Klose, Johannes; Kolbeck, Roland; Korte, Martin; Barde, Yves-Alain

    2008-02-01

    Pro- and mature BDNF activate very different receptors and intracellular pathways, potentially leading to either neuronal death or survival. Here we examined the biochemistry of endogenous BDNF in mouse neurons using sensitive reagents and found that pro-BDNF is rapidly converted intracellularly to mature BDNF, the latter being stored and released by excitatory input.

  7. Inflammation and neuronal death in the motor cortex of the wobbler mouse, an ALS animal model

    DEFF Research Database (Denmark)

    Dahlke, Carolin; Saberi, Darius; Ott, Bastian

    2015-01-01

    Background Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder of the upper and lower motor neurons, characterized by rapid progressive weakness, muscle atrophy, dysarthria, dysphagia, and dyspnea. Whereas the exact cause of ALS remains uncertain, the wobbler mouse (phenotype...

  8. Motor neuron disease in blacks

    African Journals Online (AJOL)

    1989-08-19

    Aug 19, 1989 ... We reported earlier that motor neuron disease occurs more commonly among blacks than Parkinson's disease, which is relatively rare in this race group.! The hypothesis that these conditions, and other neuronal abiotrophies, are the result of previous subclinical neuronal insult and subsequent age-related.

  9. Simple model of spiking neurons.

    Science.gov (United States)

    Izhikevich, E M

    2003-01-01

    A model is presented that reproduces spiking and bursting behavior of known types of cortical neurons. The model combines the biologically plausibility of Hodgkin-Huxley-type dynamics and the computational efficiency of integrate-and-fire neurons. Using this model, one can simulate tens of thousands of spiking cortical neurons in real time (1 ms resolution) using a desktop PC.

  10. Moving Neurons back into place

    OpenAIRE

    Kerjan, Geraldine; Gleeson, Joseph G.

    2009-01-01

    Subcortical band heterotopia (SBH) is a neuron migration disorder characterized by an aberrant ‘band-like’ accumulation of neurons within the neocortical white matter, frequently leading to mental retardation and epilepsy. SBH can now be regressed by reactivating neuronal migration.

  11. Neuronal substrate of eating disorders

    OpenAIRE

    Timofeeva, Elena; Calvez, Juliane

    2014-01-01

    Eating disorders are devastating and life-threatening psychiatric diseases. Although clinical and experimental investigations have significantly progressed in discovering the neuronal causes of eating disorders, the exact neuronal and molecular mechanisms of the development and maintenance of these pathologies are not fully understood. The complexity of the neuronal substrate of eating disorders hampers progress in revealing the precise mechanisms. The present re...

  12. Understanding Neuronal Mechanisms of Epilepsy ...

    Indian Academy of Sciences (India)

    Admin

    Control il ti. Human brain. Control epileptic. Mutani et al., 1994 ... of Calcium Transients Evoked in. Response to Spontaneous Epileptic ... Proof : Feed forward inhibition in subiculum. CA1. Subiculum. Stimulation artifact. -60 mV. Excitatory neuron. Inhibitory neuron. Excitatory neuron. Excitatory. Synapse. Inhibitory. Synapse.

  13. Brain Rhythms Connect Impaired Inhibition to Altered Cognition in Schizophrenia

    Science.gov (United States)

    Pittman-Polletta, Benjamin R.; Kocsis, Bernat; Vijayan, Sujith; Whittington, Miles A.; Kopell, Nancy J.

    2015-01-01

    In recent years, schizophrenia research has focused on inhibitory interneuron dysfunction at the level of neurobiology, and on cognitive impairments at the psychological level. Reviewing both experimental and computational findings, we show how the temporal structure of the activity of neuronal populations, exemplified by brain rhythms, can begin to bridge these levels of complexity. Oscillations in neuronal activity tie the pathophysiology of schizophrenia to alterations in local processing and large-scale coordination, and these alterations in turn can lead to the cognitive and perceptual disturbances observed in schizophrenia. PMID:25850619

  14. REMOD: a computational tool for remodeling neuronal dendrites

    Directory of Open Access Journals (Sweden)

    Panagiotis Bozelos

    2014-05-01

    Full Text Available In recent years, several modeling studies have indicated that dendritic morphology is a key determinant of how individual neurons acquire a unique signal processing profile. The highly branched dendritic structure that originates from the cell body, explores the surrounding 3D space in a fractal-like manner, until it reaches a certain amount of complexity. Its shape undergoes significant alterations not only in various neuropathological conditions, but in physiological, too. Yet, despite the profound effect that these alterations can have on neuronal function, the causal relationship between structure and function remains largely elusive. The lack of a systematic approach for remodeling neuronal cells and their dendritic trees is a key limitation that contributes to this problem. In this context, we developed a computational tool that allows the remodeling of any type of neurons, given a set of exemplar morphologies. The tool is written in Python and provides a simple GUI that guides the user through various options to manipulate selected neuronal morphologies. It provides the ability to load one or more morphology files (.swc or .hoc and choose specific dendrites to operate one of the following actions: shrink, remove, extend or branch (as shown in Figure 1. The user retains complete control over the extent of each alteration and if a chosen action is not possible due to pre-existing structural constraints, appropriate warnings are produced. Importantly, the tool can also be used to extract morphology statistics for one or multiple morphologies, including features such as the total dendritic length, path length to the root, branch order, diameter tapering, etc. Finally, an experimental utility enables the user to remodel entire dendritic trees based on preloaded statistics from a database of cell-type specific neuronal morphologies. To our knowledge, this is the first tool that allows (a the remodeling of existing –as opposed to the de novo

  15. Dendrodendritic connections between the cochlear efferent neurons in guinea pig.

    Science.gov (United States)

    Szabó, Zs; Bácskai, T; Deák, Á; Matesz, K; Veress, G; Sziklai, I

    2011-10-31

    The outer hair cells of organ of Corti are innervated by the efferent neurons of medial olivocochlear neurons (MOC) of the brainstem which modify the cochlear auditory processing and sensitivity. Most of the MOC neurons are excited by a dominant ear and only a small portion of them is excited by both ears resulting in a binaural facilitation. The functional role of the feedback system between the organ of Corti and the cochlear efferent neurons is the protection of the ear from acoustic injury. The rapid impulse propagation in the bilateral olivocochlear system is suggestive of an electrotonic interaction between the bilateral olivocochlear neurons. The morphological background of the MOC pathway is not yet completely characterized. Therefore, we have labeled the bilateral cochlear nerves with different neuronal tracers in guinea pigs. In the anesthetized animals the cochlear nerves were exposed in the basal part of the modiolus and labeled simultaneously with different retrograde fluorescent tracers. By using confocal laser scanning microscope we could detect close appositions between the dendrites of the neurons of bilateral MOC. The distance between the neighboring profiles suggested close membrane appositions without interposing glial elements. These connections might serve as one of the underlying mechanisms of the binaural facilitation mediated by the olivocochlear system. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  16. Dopamine neurons release transmitter via a flickering fusion pore.

    Science.gov (United States)

    Staal, Roland G W; Mosharov, Eugene V; Sulzer, David

    2004-04-01

    A key question in understanding mechanisms of neurotransmitter release is whether the fusion pore of a synaptic vesicle regulates the amount of transmitter released during exocytosis. We measured dopamine release from small synaptic vesicles of rat cultured ventral midbrain neurons using carbon fiber amperometry. Our data indicate that small synaptic vesicle fusion pores flicker either once or multiple times in rapid succession, with each flicker releasing approximately 25-30% of vesicular dopamine. The incidence of events with multiple flickers was reciprocally regulated by phorbol esters and staurosporine. Thus, dopamine neurons regulate the amount of neurotransmitter released by small synaptic vesicles by controlling the number of fusion pore flickers per exocytotic event. This mode of exocytosis is a potential mechanism whereby neurons can rapidly reuse vesicles without undergoing the comparatively slow process of recycling.

  17. A mechanism for cognitive dynamics: neuronal communication through neuronal coherence.

    Science.gov (United States)

    Fries, Pascal

    2005-10-01

    At any one moment, many neuronal groups in our brain are active. Microelectrode recordings have characterized the activation of single neurons and fMRI has unveiled brain-wide activation patterns. Now it is time to understand how the many active neuronal groups interact with each other and how their communication is flexibly modulated to bring about our cognitive dynamics. I hypothesize that neuronal communication is mechanistically subserved by neuronal coherence. Activated neuronal groups oscillate and thereby undergo rhythmic excitability fluctuations that produce temporal windows for communication. Only coherently oscillating neuronal groups can interact effectively, because their communication windows for input and for output are open at the same times. Thus, a flexible pattern of coherence defines a flexible communication structure, which subserves our cognitive flexibility.

  18. Enhanced sensitivity of dopaminergic neurons to rotenone-induced toxicity with aging.

    Science.gov (United States)

    Phinney, Amie L; Andringa, Gerda; Bol, John G J M; Wolters, Erik Ch; van Muiswinkel, Freek L; van Dam, Anne-Marie W; Drukarch, Benjamin

    2006-05-01

    Rotenone has been reported to induce various degrees of Parkinsonism in rats. We tested whether advancing age alters the sensitivity of dopaminergic neurons to rotenone. A low, systemic dose of rotenone had no effect on young rats, but led to a 20-30% reduction of tyrosine hydroxylase-positive neurons in the substantia nigra of older rats. The effect was specific to nigral dopaminergic neurons and may be associated with the increase of glial cell activation in older rats. These data suggest that age enhances the sensitivity of dopaminergic neurons to rotenone and should be considered when assessing models of Parkinson's disease.

  19. Serotonin: a regulator of neuronal morphology and circuitry

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    Daubert, Elizabeth A.; Condron, Barry G.

    2010-01-01

    Serotonin is an important neuromodulator associated with a wide range of physiological effects in the central nervous system. The exact mechanisms for how serotonin influences brain development are not well understood, although studies in invertebrate and vertebrate model organisms are beginning to unravel a regulatory role for serotonin in neuronal morphology and circuit formation. Recent data suggests a developmental window during which altered serotonin levels permanently impact circuitry, however, the temporal constraints and molecular mechanisms responsible are still under investigation. Growing evidence suggests that alterations in early serotonin signaling contribute to a number of neurodevelopmental and neuropsychiatric disorders. Thus, understanding how altered serotonin signaling affects neuronal morphology and plasticity, and ultimately animal physiology and pathophysiology, will be of great significance. PMID:20561690

  20. Evidence for neuronal localisation of enteroviral sequences in motor neurone disease/amyotrophic lateral sclerosis by in situ hybridization.

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    Woodall, C J; Graham, D I

    2004-01-01

    Sequences resembling those of human enterovirus type B sequences have been associated with motor neurone disease/amyotrophic lateral sclerosis. In a previous study we detected enteroviral sequences in spinal cord/brain stem from cases of motor neurone disease/amyotrophic lateral sclerosis, but not controls. Adjacent tissue sections to two of those strongly positive for these sequences by reverse-transcriptase polymerase chain reaction were analyzed by in situ hybridization with digoxigenin-labelled virus-specific antisense riboprobes. In one case, a female aged 83 showing 12 month rapid progressive disease, signal was specifically localized to cells identifiable as motor neurones of the anterior horn. In another case, a male aged 63 with a 60-month history of progressive muscle weakness, dysarthia, dyspnoea and increased tendon reflexes, signal was located to neurones in the gracile/cuneate nuclei of the brain stem tissue block that had been analyzed. This case showed loss of neurones in the anterior horn of the spinal cord by histopathologic examination which would account for clinical signs of motor neurone disease/amyotrophic lateral sclerosis. Dysfunction of the gracile/cuneate nuclei might have been masked by the paralytic disease. These structures are adjacent to the hypoglossal nuclei, and suggest either localised dissemination from hypoglossal nuclei or a possible route of dissemination of infection through the brainstem to the hypoglossal nuclei. These findings provide further evidence for the possible involvement of enteroviruses in motor neurone disease/amyotrophic lateral sclerosis.

  1. Evidence for neuronal localisation of enteroviral sequences in motor neurone disease/amyotrophic lateral sclerosis by in situ hybridization

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    CJ Woodall

    2009-06-01

    Full Text Available Sequences resembling those of human enterovirus type B sequences have been associated with motor neurone disease/ amyotrophic lateral sclerosis. In a previous study we detected enteroviral sequences in spinal cord/brain stem from cases of motor neurone disease/amyotrophic lateral sclerosis, but not controls. Adjacent tissue sections to two of those strongly positive for these sequences by reverse-transcriptase polymerase chain reaction were analyzed by in situ hybridization with digoxigenin-labelled virus-specific antisense riboprobes. In one case, a female aged 83 showing 12 month rapid progressive disease, signal was specifically localized to cells identifiable as motor neurones of the anterior horn. In another case, a male aged 63 with a 60-month history of progressive muscle weakness, dysarthia, dyspnoea and increased tendon reflexes, signal was located to neurones in the gracile/cuneate nuclei of the brain stem tissue block that had been analyzed. This case showed loss of neurones in the anterior horn of the spinal cord by histopathologic examination which would account for clinical signs of motor neurone disease/amyotrophic lateral sclerosis. Dysfunction of the gracile/cuneate nuclei might have been masked by the paralytic disease. These structures are adjacent to the hypoglossal nuclei, and suggest either localised dissemination from hypoglossal nuclei or a possible route of dissemination of infection through the brainstem to the hypoglossal nuclei. These findings provide further evidence for the possible involvement of enteroviruses in motor neurone disease/amyotrophic lateral sclerosis.

  2. Asynchronous Cholinergic Drive Correlates with Excitation-Inhibition Imbalance via a Neuronal Ca2+ Sensor Protein

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    Keming Zhou

    2017-05-01

    Full Text Available Excitation-inhibition imbalance in neural networks is widely linked to neurological and neuropsychiatric disorders. However, how genetic factors alter neuronal activity, leading to excitation-inhibition imbalance, remains unclear. Here, using the C. elegans locomotor circuit, we examine how altering neuronal activity for varying time periods affects synaptic release pattern and animal behavior. We show that while short-duration activation of excitatory cholinergic neurons elicits a reversible enhancement of presynaptic strength, persistent activation results to asynchronous and reduced cholinergic drive, inducing imbalance between endogenous excitation and inhibition. We find that the neuronal calcium sensor protein NCS-2 is required for asynchronous cholinergic release in an activity-dependent manner and dampens excitability of inhibitory neurons non-cell autonomously. The function of NCS-2 requires its Ca2+ binding and membrane association domains. These results reveal a synaptic mechanism implicating asynchronous release in regulation of excitation-inhibition balance.

  3. Overproduction of Upper-Layer Neurons in the Neocortex Leads to Autism-like Features in Mice

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    Wei-Qun Fang

    2014-12-01

    Full Text Available The functional integrity of the neocortex depends upon proper numbers of excitatory and inhibitory neurons; however, the consequences of dysregulated neuronal production during the development of the neocortex are unclear. As excess cortical neurons are linked to the neurodevelopmental disorder autism, we investigated whether the overproduction of neurons leads to neocortical malformation and malfunction in mice. We experimentally increased the number of pyramidal neurons in the upper neocortical layers by using the small molecule XAV939 to expand the intermediate progenitor population. The resultant overpopulation of neurons perturbs development of dendrites and spines of excitatory neurons and alters the laminar distribution of interneurons. Furthermore, these phenotypic changes are accompanied by dysregulated excitatory and inhibitory synaptic connection and balance. Importantly, these mice exhibit behavioral abnormalities resembling those of human autism. Thus, our findings collectively suggest a causal relationship between neuronal overproduction and autism-like features, providing developmental insights into the etiology of autism.

  4. Metamorphosis of an identified serotonergic neuron in the Drosophila olfactory system.

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    Roy, Bidisha; Singh, Ajeet P; Shetty, Chetak; Chaudhary, Varun; North, Annemarie; Landgraf, Matthias; Vijayraghavan, K; Rodrigues, Veronica

    2007-10-24

    Odors are detected by sensory neurons that carry information to the olfactory lobe where they connect to projection neurons and local interneurons in glomeruli: anatomically well-characterized structures that collect, integrate and relay information to higher centers. Recent studies have revealed that the sensitivity of such networks can be modulated by wide-field feedback neurons. The connectivity and function of such feedback neurons are themselves subject to alteration by external cues, such as hormones, stress, or experience. Very little is known about how this class of central neurons changes its anatomical properties to perform functions in altered developmental contexts. A mechanistic understanding of how central neurons change their anatomy to meet new functional requirements will benefit greatly from the establishment of a model preparation where cellular and molecular changes can be examined in an identified central neuron. In this study, we examine a wide-field serotonergic neuron in the Drosophila olfactory pathway and map the dramatic changes that it undergoes from larva to adult. We show that expression of a dominant-negative form of the ecdysterone receptor prevents remodeling. We further use different transgenic constructs to silence neuronal activity and report defects in the morphology of the adult-specific dendritic trees. The branching of the presynaptic axonal arbors is regulated by mechanisms that affect axon growth and retrograde transport. The neuron develops its normal morphology in the absence of sensory input to the antennal lobe, or of the mushroom bodies. However, ablation of its presumptive postsynaptic partners, the projection neurons and/or local interneurons, affects the growth and branching of terminal arbors. Our studies establish a cellular system for studying remodeling of a central neuromodulatory feedback neuron and also identify key elements in this process. Understanding the morphogenesis of such neurons, which have been

  5. Metamorphosis of an identified serotonergic neuron in the Drosophila olfactory system

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    Landgraf Matthias

    2007-10-01

    Full Text Available Abstract Background Odors are detected by sensory neurons that carry information to the olfactory lobe where they connect to projection neurons and local interneurons in glomeruli: anatomically well-characterized structures that collect, integrate and relay information to higher centers. Recent studies have revealed that the sensitivity of such networks can be modulated by wide-field feedback neurons. The connectivity and function of such feedback neurons are themselves subject to alteration by external cues, such as hormones, stress, or experience. Very little is known about how this class of central neurons changes its anatomical properties to perform functions in altered developmental contexts. A mechanistic understanding of how central neurons change their anatomy to meet new functional requirements will benefit greatly from the establishment of a model preparation where cellular and molecular changes can be examined in an identified central neuron. Results In this study, we examine a wide-field serotonergic neuron in the Drosophila olfactory pathway and map the dramatic changes that it undergoes from larva to adult. We show that expression of a dominant-negative form of the ecdysterone receptor prevents remodeling. We further use different transgenic constructs to silence neuronal activity and report defects in the morphology of the adult-specific dendritic trees. The branching of the presynaptic axonal arbors is regulated by mechanisms that affect axon growth and retrograde transport. The neuron develops its normal morphology in the absence of sensory input to the antennal lobe, or of the mushroom bodies. However, ablation of its presumptive postsynaptic partners, the projection neurons and/or local interneurons, affects the growth and branching of terminal arbors. Conclusion Our studies establish a cellular system for studying remodeling of a central neuromodulatory feedback neuron and also identify key elements in this process

  6. Phosphoinositide signaling in somatosensory neurons

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    Rohacs, Tibor

    2015-01-01

    Somatosensory neurons of the dorsal root ganglia (DRG) and trigeminal ganglia (TG) are responsible for detecting thermal and tactile stimuli. They are also the primary neurons mediating pain and itch. A large number of cell surface receptors in these neurons couple to phospholipase C (PLC) enzymes leading to the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and the generation of downstream signaling molecules. These neurons also express many different ion channels, several of which are regulated by phosphoinositides. This review will summarize the knowledge on phosphoinositide signaling in these neurons, with special focus on effects on sensory and other ion channels. PMID:26724974

  7. Microglia Control Neuronal Network Excitability via BDNF Signalling

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    Francesco Ferrini

    2013-01-01

    Full Text Available Microglia-neuron interactions play a crucial role in several neurological disorders characterized by altered neural network excitability, such as epilepsy and neuropathic pain. While a series of potential messengers have been postulated as substrates of the communication between microglia and neurons, including cytokines, purines, prostaglandins, and nitric oxide, the specific links between messengers, microglia, neuronal networks, and diseases have remained elusive. Brain-derived neurotrophic factor (BDNF released by microglia emerges as an exception in this riddle. Here, we review the current knowledge on the role played by microglial BDNF in controlling neuronal excitability by causing disinhibition. The efforts made by different laboratories during the last decade have collectively provided a robust mechanistic paradigm which elucidates the mechanisms involved in the synthesis and release of BDNF from microglia, the downstream TrkB-mediated signals in neurons, and the biophysical mechanism by which disinhibition occurs, via the downregulation of the K+-Cl− cotransporter KCC2, dysrupting Cl−homeostasis, and hence the strength of GABAA- and glycine receptor-mediated inhibition. The resulting altered network activity appears to explain several features of the associated pathologies. Targeting the molecular players involved in this canonical signaling pathway may lead to novel therapeutic approach for ameliorating a wide array of neural dysfunctions.

  8. Neuron-microglia interactions in mental health disorders: 'For better, and for worse'

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    Eric S Wohleb

    2016-11-01

    Full Text Available Persistent cognitive and behavioral symptoms that characterize many mental health disorders arise from impaired neuroplasticity in several key corticolimbic brain regions. Recent evidence suggest that reciprocal neuron-microglia interactions shape neuroplasticity during physiological conditions, implicating microglia in the neurobiology of mental health disorders. Neuron-microglia interactions are modulated by several molecular and cellular pathways and dysregulation of these pathways often have neurobiological consequences, including aberrant neuronal responses and microglia activation. The interactions between neurons and microglia have implications for mental health disorders as rodent stress models cause concomitant neuronal dystrophy and alterations in microglia morphology and function. In this context, functional changes in microglia may be indicative of an immune state termed parainflammation in which tissue-resident macrophages (i.e., microglia respond to malfunctioning cells by initiating modest inflammation in an attempt to restore homeostasis. Thus, aberrant neuronal activity and release of damage-associated signals during repeated stress exposure may contribute to functional changes in microglia and resultant parainflammation. Furthermore, accumulating evidence shows that uncoupling neuron-microglia interactions may contribute to altered neuroplasticity and associated anxiety- or depressive-like behaviors. Additional work shows that microglia have varied phenotypes in specific brain regions, which may underlie divergent neuroplasticity observed in corticolimbic structures following stress exposure. These findings indicate that neuron-microglia interactions are critical mediators of the interface between adaptive, homeostatic neuronal function and the neurobiology of mental health disorders.

  9. A high-throughput model for investigating neuronal function and synaptic transmission in cultured neuronal networks.

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    Virdee, Jasmeet K; Saro, Gabriella; Fouillet, Antoine; Findlay, Jeremy; Ferreira, Filipa; Eversden, Sarah; O'Neill, Michael J; Wolak, Joanna; Ursu, Daniel

    2017-11-03

    Loss of synapses or alteration of synaptic activity is associated with cognitive impairment observed in a number of psychiatric and neurological disorders, such as schizophrenia and Alzheimer's disease. Therefore successful development of in vitro methods that can investigate synaptic function in a high-throughput format could be highly impactful for neuroscience drug discovery. We present here the development, characterisation and validation of a novel high-throughput in vitro model for assessing neuronal function and synaptic transmission in primary rodent neurons. The novelty of our approach resides in the combination of the electrical field stimulation (EFS) with data acquisition in spatially separated areas of an interconnected neuronal network. We integrated our methodology with state of the art drug discovery instrumentation (FLIPR Tetra) and used selective tool compounds to perform a systematic pharmacological validation of the model. We investigated pharmacological modulators targeting pre- and post-synaptic receptors (AMPA, NMDA, GABA-A, mGluR2/3 receptors and Nav, Cav voltage-gated ion channels) and demonstrated the ability of our model to discriminate and measure synaptic transmission in cultured neuronal networks. Application of the model described here as an unbiased phenotypic screening approach will help with our long term goals of discovering novel therapeutic strategies for treating neurological disorders.

  10. Neuron-specific splicing.

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    Hakim, Nor Hakimah Ab; Majlis, Burhanuddin Yeop; Suzuki, Hitoshi; Tsukahara, Toshifumi

    2017-03-22

    During pre-mRNA splicing events, introns are removed from the pre-mRNA, and the remaining exons are connected together to form a single continuous molecule. Alternative splicing is a common mechanism for the regulation of gene expression in eukaryotes. More than 90% of human genes are known to undergo alternative splicing. The most common type of alternative splicing is exon skipping, which is also known as cassette exon. Other known alternative splicing events include alternative 5' splice sites, alternative 3' splice sites, intron retention, and mutually exclusive exons. Alternative splicing events are controlled by regulatory proteins responsible for both positive and negative regulation. In this review, we focus on neuronal splicing regulators and discuss several notable regulators in depth. In addition, we have also included an example of splicing regulation mediated by the RBFox protein family. Lastly, as previous studies have shown that a number of splicing factors are associated with neuronal diseases such as Alzheime's disease (AD) and Autism spectrum disorder (ASD), here we consider their importance in neuronal diseases wherein the underlying mechanisms have yet to be elucidated.

  11. Enhanced astrocytic nitric oxide production and neuronal modifications in the neocortex of a NOS2 mutant mouse.

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    Yossi Buskila

    Full Text Available BACKGROUND: It has been well accepted that glial cells in the central nervous system (CNS produce nitric oxide (NO through the induction of a nitric oxide synthase isoform (NOS2 only in response to various insults. Recently we described rapid astroglial, NOS2-dependent, NO production in the neocortex of healthy mice on a time scale relevant to neuronal activity. To explore a possible role for astroglial NOS2 in normal brain function we investigated a NOS2 knockout mouse (B6;129P2-Nos2(tm1Lau/J, Jackson Laboratory. Previous studies of this mouse strain revealed mainly altered immune responses, but no compensatory pathways and no CNS abnormalities have been reported. METHODOLOGY/PRINCIPAL FINDINGS: To our surprise, using NO imaging in brain slices in combination with biochemical methods we uncovered robust NO production by neocortical astrocytes of the NOS2 mutant. These findings indicate the existence of an alternative pathway that increases basal NOS activity. In addition, the astroglial mutation instigated modifications of neuronal attributes, shown by changes in the membrane properties of pyramidal neurons, and revealed in distinct behavioral abnormalities characterized by an increase in stress-related parameters. CONCLUSIONS/SIGNIFICANCE: The results strongly indicate the involvement of astrocytic-derived NO in modifying the activity of neuronal networks. In addition, the findings corroborate data linking NO signaling with stress-related behavior, and highlight the potential use of this genetic model for studies of stress-susceptibility. Lastly, our results beg re-examination of previous studies that used this mouse strain to examine the pathophysiology of brain insults, assuming lack of astrocytic nitrosative reaction.

  12. Neto2 Assembles with Kainate Receptors in DRG Neurons during Development and Modulates Neurite Outgrowth in Adult Sensory Neurons.

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    Vernon, Claire G; Swanson, Geoffrey T

    2017-03-22

    Peripheral sensory neurons in the dorsal root ganglia (DRG) are the initial transducers of sensory stimuli, including painful stimuli, from the periphery to central sensory and pain-processing centers. Small- to medium-diameter non-peptidergic neurons in the neonatal DRG express functional kainate receptors (KARs), one of three subfamilies of ionotropic glutamate receptors, as well as the putative KAR auxiliary subunit Neuropilin- and tolloid-like 2 (Neto2). Neto2 alters recombinant KAR function markedly but has yet to be confirmed as an auxiliary subunit that assembles with and alters the function of endogenous KARs. KARs in neonatal DRG require the GluK1 subunit as a necessary constituent, but it is unclear to what extent other KAR subunits contribute to the function and proposed roles of KARs in sensory ganglia, which include promotion of neurite outgrowth and modulation of glutamate release at the DRG-dorsal horn synapse. In addition, KARs containing the GluK1 subunit are implicated in modes of persistent but not acute pain signaling. We show here that the Neto2 protein is highly expressed in neonatal DRG and modifies KAR gating in DRG neurons in a developmentally regulated fashion in mice. Although normally at very low levels in adult DRG neurons, Neto2 protein expression can be upregulated via MEK/ERK signaling and after sciatic nerve crush and Neto2 -/- neurons from adult mice have stunted neurite outgrowth. These data confirm that Neto2 is a bona fide KAR auxiliary subunit that is an important constituent of KARs early in sensory neuron development and suggest that Neto2 assembly is critical to KAR modulation of DRG neuron process outgrowth. SIGNIFICANCE STATEMENT Pain-transducing peripheral sensory neurons of the dorsal root ganglia (DRG) express kainate receptors (KARs), a subfamily of glutamate receptors that modulate neurite outgrowth and regulate glutamate release at the DRG-dorsal horn synapse. The putative KAR auxiliary subunit Neuropilin- and

  13. Mechanical stress activates neurites and somata of myenteric neurons

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    Eva Maria Kugler

    2015-09-01

    Full Text Available The particular location of myenteric neurons, sandwiched between the 2 muscle layers of the gut, implies that their somata and neurites undergo mechanical stress during gastrointestinal motility. Existence of mechanosensitive enteric neurons (MEN is undoubted but many of their basic features remain to be studied. In this study, we used ultra-fast neuroimaging to record activity of primary cultured myenteric neurons of guinea pig and human intestine after von Frey hair evoked deformation of neurites and somata. Independent component analysis was applied to reconstruct neuronal morphology and follow neuronal signals. Of the cultured neurons 45% (114 out of 256, 30 guinea pigs responded to neurite probing with a burst spike frequency of 13.4 Hz. Action potentials generated at the stimulation site invaded the soma and other neurites. Mechanosensitive sites were expressed across large areas of neurites. Many mechanosensitive neurites appeared to have afferent and efferent functions as those that responded to deformation also conducted spikes coming from the soma. Mechanosensitive neurites were also activated by nicotine application. This supported the concept of multifunctional MEN. 14% of the neurons (13 out of 96, 18 guinea pigs responded to soma deformation with burst spike discharge of 17.9 Hz. Firing of MEN adapted rapidly (RAMEN, slowly (SAMEN or ultra-slowly (USAMEN. The majority of MEN showed SAMEN behavior although significantly more RAMEN occurred after neurite probing. Cultured myenteric neurons from human intestine had similar properties. Compared to MEN, dorsal root ganglion neurons were activated by neurite but not by soma deformation with slow adaptation of firing. We demonstrated that MEN exhibit specific features very likely reflecting adaptation to their specialized functions in the gut.

  14. Associative Learning Drives the Formation of Silent Synapses in Neuronal Ensembles of the Nucleus Accumbens.

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    Whitaker, Leslie R; Carneiro de Oliveira, Paulo E; McPherson, Kylie B; Fallon, Rebecca V; Planeta, Cleopatra S; Bonci, Antonello; Hope, Bruce T

    2016-08-01

    Learned associations between environmental stimuli and rewards play a critical role in addiction. Associative learning requires alterations in sparsely distributed populations of strongly activated neurons, or neuronal ensembles. Until recently, assessment of functional alterations underlying learned behavior was restricted to global neuroadaptations in a particular brain area or cell type, rendering it impossible to identify neuronal ensembles critically involved in learned behavior. We used Fos-GFP transgenic mice that contained a transgene with a Fos promoter driving expression of green fluorescent protein (GFP) to detect neurons that were strongly activated during associative learning, in this case, context-independent and context-specific cocaine-induced locomotor sensitization. Whole-cell electrophysiological recordings were used to assess synaptic alterations in specifically activated GFP-positive (GFP+) neurons compared with surrounding nonactivated GFP-negative (GFP-) neurons 90 min after the sensitized locomotor response. After context-independent cocaine sensitization, cocaine-induced locomotion was equally sensitized by repeated cocaine injections in two different sensitization contexts. Correspondingly, silent synapses in these mice were induced in GFP+ neurons, but not GFP- neurons, after sensitization in both of these contexts. After context-specific cocaine sensitization, cocaine-induced locomotion was sensitized exclusively in mice trained and tested in the same context (paired group), but not in mice that were trained in one context and then tested in a different context (unpaired group). Silent synapses increased in GFP+ neurons, but not in GFP- neurons from mice in the paired group, but not from mice in the unpaired group. Our results indicate that silent synapses are formed only in neuronal ensembles of the nucleus accumbens shell that are related to associative learning. Published by Elsevier Inc.

  15. Altering the Balance between Excitation and Inhibition in Cultured Neural Networks

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    Dzakpasu, Rhonda

    2010-03-01

    How is the network temporal structure altered when the balance between excitation and inhibition is changed? Proper balance is essential for normal brain function, including cognitive processing, the representation of sensory information and motor control. When the balance is compromised, neurological disorders may result. We use a simple reduced experimental system to investigate how manipulating the number of inhibitory neurons in a network of cultured hippocampal neurons affects synchronized bursting activity, the most prominent temporal signature of cultured hippocampal networks. Inhibitory neurons are thought to control spike timing and modulate network excitability and their absence may lead to widespread synchronization. We culture dissociated hippocampal neurons with varying quantities of inhibitory neurons on an 8x8 grid of extracellular electrodes and study how inhibitory neurons modulate network temporal dynamics. We show that as the proportion of inhibitory neurons increase, there is a dramatic transition in the temporal pattern.

  16. Different patterns of neuronal activity trigger distinct responses of oligodendrocyte precursor cells in the corpus callosum.

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    Balint Nagy

    2017-08-01

    Full Text Available In the developing and adult brain, oligodendrocyte precursor cells (OPCs are influenced by neuronal activity: they are involved in synaptic signaling with neurons, and their proliferation and differentiation into myelinating glia can be altered by transient changes in neuronal firing. An important question that has been unanswered is whether OPCs can discriminate different patterns of neuronal activity and respond to them in a distinct way. Here, we demonstrate in brain slices that the pattern of neuronal activity determines the functional changes triggered at synapses between axons and OPCs. Furthermore, we show that stimulation of the corpus callosum at different frequencies in vivo affects proliferation and differentiation of OPCs in a dissimilar way. Our findings suggest that neurons do not influence OPCs in "all-or-none" fashion but use their firing pattern to tune the response and behavior of these nonneuronal cells.

  17. Intrinsic membrane properties of central vestibular neurons in rodents.

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    Eugène, Daniel; Idoux, Erwin; Beraneck, Mathieu; Moore, L E; Vidal, Pierre-Paul

    2011-05-01

    Numerous studies in rodents have shown that the functional efficacy of several neurotransmitter receptors and the intrinsic membrane excitability of central vestibular neurons, as well as the organization of synaptic connections within and between vestibular nuclei can be modified during postnatal development, after a lesion of peripheral vestibular organs or in vestibular-deficient mutant animals. This review mainly focuses on the intrinsic membrane properties of neurons of the medial vestibular nuclei of rodents, their postnatal maturation, and changes following experimental or congenital alterations in vestibular inputs. It also presents the concomitant modifications in the distribution of these neurons into different neuron types, which has been based on their membrane properties in relation to their anatomical, biochemical, or functional properties. The main points discussed in this review are that (1) the intrinsic membrane properties can be used to distinguish between two dominant types of neurons, (2) the system remains plastic throughout the whole life of the animal, and finally, (3) the intracellular calcium concentration has a major effect on the intrinsic membrane properties of central vestibular neurons.

  18. Learning and Stress Shape the Reward Response Patterns of Serotonin Neurons.

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    Zhong, Weixin; Li, Yi; Feng, Qiru; Luo, Minmin

    2017-09-13

    The ability to predict reward promotes animal survival. Both dopamine neurons in the ventral tegmental area and serotonin neurons in the dorsal raphe nucleus (DRN) participate in reward processing. Although the learning effects on dopamine neurons have been extensively characterized, it remains largely unknown how the response of serotonin neurons evolves during learning. Moreover, although stress is known to strongly influence reward-related behavior, we know very little about how stress modulates neuronal reward responses. By monitoring Ca 2+ signals during the entire process of Pavlovian conditioning, we here show that learning differentially shapes the response patterns of serotonin neurons and dopamine neurons in mice of either sex. Serotonin neurons gradually develop a slow ramp-up response to the reward-predicting cue, and ultimately remain responsive to the reward, whereas dopamine neurons increase their response to the cue but reduce their response to the reward. For both neuron types, the responses to the cue and the reward depend on reward value, are reversible when the reward is omitted, and are rapidly reinstated by restoring the reward. We also found that stressors including head restraint and fearful context substantially reduce the response strength of both neuron types, to both the cue and the reward. These results reveal the dynamic nature of the reward responses, support the hypothesis that DRN serotonin neurons signal the current likelihood of receiving a net benefit, and suggest that the inhibitory effect of stress on the reward responses of serotonin neurons and dopamine neurons may contribute to stress-induced anhedonia. SIGNIFICANCE STATEMENT Both serotonin neurons in the dorsal raphe and dopamine neurons in the ventral tegmental area are intimately involved in reward processing. Using long-term fiber photometry of Ca 2+ signals from freely behaving mice, we here show that learning produces a ramp-up activation pattern in serotonin neurons

  19. Early steps toward understanding neuronal communication.

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    Snyder, Adam C; Smith, Matthew A

    2017-10-25

    The computational power of the brain arises from the complex interactions between neurons. One straightforward method to quantify the strength of neuronal interactions is by measuring correlation and coherence. Efforts to measure correlation have been advancing rapidly of late, spurred by the development of advanced recording technologies enabling recording from many neurons and brain areas simultaneously. This review highlights recent results that provide clues into the principles of neural coordination, connections to cognitive and neurological phenomena, and key directions for future research. The correlation structure of neural activity in the brain has important consequences for the encoding properties of neural populations. Recent studies have shown that this correlation structure is not fixed, but adapts in a variety of contexts in ways that appear beneficial to task performance. By studying these changes in biological neural networks and computational models, researchers have improved our understanding of the principles guiding neural communication. Correlation and coherence are highly informative metrics for studying coding and communication in the brain. Recent findings have emphasized how the brain modifies correlation structure dynamically in order to improve information-processing in a goal-directed fashion. One key direction for future research concerns how to leverage these dynamic changes for therapeutic purposes.

  20. Parvalbumin+ Neurons and Npas1+ Neurons Are Distinct Neuron Classes in the Mouse External Globus Pallidus

    Science.gov (United States)

    Hernández, Vivian M.; Hegeman, Daniel J.; Cui, Qiaoling; Kelver, Daniel A.; Fiske, Michael P.; Glajch, Kelly E.; Pitt, Jason E.; Huang, Tina Y.; Justice, Nicholas J.

    2015-01-01

    Compelling evidence suggests that pathological activity of the external globus pallidus (GPe), a nucleus in the basal ganglia, contributes to the motor symptoms of a variety of movement disorders such as Parkinson's disease. Recent studies have challenged the idea that the GPe comprises a single, homogenous population of neurons that serves as a simple relay in the indirect pathway. However, we still lack a full understanding of the diversity of the neurons that make up the GPe. Specifically, a more precise classification scheme is needed to better describe the fundamental biology and function of different GPe neuron classes. To this end, we generated a novel multicistronic BAC (bacterial artificial chromosome) transgenic mouse line under the regulatory elements of the Npas1 gene. Using a combinatorial transgenic and immunohistochemical approach, we discovered that parvalbumin-expressing neurons and Npas1-expressing neurons in the GPe represent two nonoverlapping cell classes, amounting to 55% and 27% of the total GPe neuron population, respectively. These two genetically identified cell classes projected primarily to the subthalamic nucleus and to the striatum, respectively. Additionally, parvalbumin-expressing neurons and Npas1-expressing neurons were distinct in their autonomous and driven firing characteristics, their expression of intrinsic ion conductances, and their responsiveness to chronic 6-hydroxydopamine lesion. In summary, our data argue that parvalbumin-expressing neurons and Npas1-expressing neurons are two distinct functional classes of GPe neurons. This work revises our understanding of the GPe, and provides the foundation for future studies of its function and dysfunction. SIGNIFICANCE STATEMENT Until recently, the heterogeneity of the constituent neurons within the external globus pallidus (GPe) was not fully appreciated. We addressed this knowledge gap by discovering two principal GPe neuron classes, which were identified by their nonoverlapping

  1. Astroglial networks promote neuronal coordination.

    Science.gov (United States)

    Chever, Oana; Dossi, Elena; Pannasch, Ulrike; Derangeon, Mickael; Rouach, Nathalie

    2016-01-12

    Astrocytes interact with neurons to regulate network activity. Although the gap junction subunits connexin 30 and connexin 43 mediate the formation of extensive astroglial networks that cover large functional neuronal territories, their role in neuronal synchronization remains unknown. Using connexin 30- and connexin 43-deficient mice, we showed that astroglial networks promoted sustained population bursts in hippocampal slices by setting the basal active state of neurons. Astroglial networks limited excessive neuronal depolarization induced by spontaneous synaptic activity, increased neuronal release probability, and favored the recruitment of neurons during bursting, thus promoting the coordinated activation of neuronal networks. In vivo, this sustained neuronal coordination translated into increased severity of acutely evoked epileptiform events and convulsive behavior. These results revealed that connexin-mediated astroglial networks synchronize bursting of neuronal assemblies, which can exacerbate pathological network activity and associated behavior. Our data thus provide molecular and biophysical evidence predicting selective astroglial gap junction inhibitors as anticonvulsive drugs. Copyright © 2016, American Association for the Advancement of Science.

  2. 5-HT inhibition of rat insulin 2 promoter Cre recombinase transgene and proopiomelanocortin neuron excitability in the mouse arcuate nucleus.

    Science.gov (United States)

    Hisadome, K; Smith, M A; Choudhury, A I; Claret, M; Withers, D J; Ashford, M L J

    2009-03-03

    A number of anti-obesity agents have been developed that enhance hypothalamic 5-HT transmission. Various studies have demonstrated that arcuate neurons, which express proopiomelanocortin peptides (POMC neurons), and neuropeptide Y with agouti-related protein (NPY/AgRP) neurons, are components of the hypothalamic circuits responsible for energy homeostasis. An additional arcuate neuron population, rat insulin 2 promoter Cre recombinase transgene (RIPCre) neurons, has recently been implicated in hypothalamic melanocortin circuits involved in energy balance. It is currently unclear how 5-HT modifies neuron excitability in these local arcuate neuronal circuits. We show that 5-HT alters the excitability of the majority of mouse arcuate RIPCre neurons, by either hyperpolarization and inhibition or depolarization and excitation. RIPCre neurons sensitive to 5-HT, predominantly exhibit hyperpolarization and pharmacological studies indicate that inhibition of neuronal firing is likely to be through 5-HT(1F) receptors increasing current through a voltage-dependent potassium conductance. Indeed, 5-HT(1F) receptor immunoreactivity co-localizes with RIPCre green fluorescent protein expression. A minority population of POMC neurons also respond to 5-HT by hyperpolarization, and this appears to be mediated by the same receptor-channel mechanism. As neither POMC nor RIPCre neuronal populations display a common electrical response to 5-HT, this may indicate that sub-divisions of POMC and RIPCre neurons exist, perhaps serving different outputs.

  3. The role of Serine Proteases and Serine Protease Inhibitors in the migration of Gonadotropin-Releasing Hormone neurons

    Directory of Open Access Journals (Sweden)

    Silverman Ann-Judith

    2002-02-01

    Full Text Available Abstract Background Mechanisms regulating neuronal migration during development remain largely undefined. Extracellular matrix cues, target site released factors, and components of the migratory neurons themselves are likely all coordinated in time and space directing neurons to their appropriate locations. We have studied the effects of proteases and their inhibitors on the extracellular matrix and the consequences to the migration of gonadotropin releasing hormone (GnRH neurons in the embryonic chick. Chick GnRH neurons differentiate in the olfactory epithelium, migrate along the olfactory nerve and enter the forebrain. The accessibility of this coherent cell group make it amenable for studying protease/inhibitor roles in migratory processes. Results Affigel blue beads were used to deliver a serine protease inhibitor, protease nexin-1 (PN-1, and a target protease, trypsin, to the olfactory epithelium coincident with initiation of GnRH neuronal migration. PN-1 inhibited neuronal migration while trypsin accelerated their transit into the CNS. Prior to initiation of migration, neither PN-1 nor trypsin altered the timing of neuronal exit. Trypsin did, however, accelerate the timing of neuronal crossing into the nerve-forebrain junction. Conclusions These data support the hypothesis that protease activity modulates neuronal movements across barriers. Moreover, the data suggest, for the first time, that aspects of GnRH neuronal migration may be cell autonomous but modulated by ECM alterations.

  4. Motor neurons and the generation of spinal motor neurons diversity

    OpenAIRE

    Nicolas eStifani

    2014-01-01

    Motor neurons (MNs) are neuronal cells located in the central nervous system (CNS) controlling a variety of downstream targets. This function infers the existence of MN subtypes matching the identity of the targets they innervate. To illustrate the mechanism involved in the generation of cellular diversity and the acquisition of specific identity, this review will focus on spinal motor neurons (SpMNs) that have been the core of significant work and discoveries during the last decades. SpMNs a...

  5. Changes in Appetitive Associative Strength Modulates Nucleus Accumbens, But Not Orbitofrontal Cortex Neuronal Ensemble Excitability.

    Science.gov (United States)

    Ziminski, Joseph J; Hessler, Sabine; Margetts-Smith, Gabriella; Sieburg, Meike C; Crombag, Hans S; Koya, Eisuke

    2017-03-22

    Cues that predict the availability of food rewards influence motivational states and elicit food-seeking behaviors. If a cue no longer predicts food availability, then animals may adapt accordingly by inhibiting food-seeking responses. Sparsely activated sets of neurons, coined "neuronal ensembles," have been shown to encode the strength of reward-cue associations. Although alterations in intrinsic excitability have been shown to underlie many learning and memory processes, little is known about these properties specifically on cue-activated neuronal ensembles. We examined the activation patterns of cue-activated orbitofrontal cortex (OFC) and nucleus accumbens (NAc) shell ensembles using wild-type and Fos-GFP mice, which express green fluorescent protein (GFP) in activated neurons, after appetitive conditioning with sucrose and extinction learning. We also investigated the neuronal excitability of recently activated, GFP+ neurons in these brain areas using whole-cell electrophysiology in brain slices. Exposure to a sucrose cue elicited activation of neurons in both the NAc shell and OFC. In the NAc shell, but not the OFC, these activated GFP+ neurons were more excitable than surrounding GFP- neurons. After extinction, the number of neurons activated in both areas was reduced and activated ensembles in neither area exhibited altered excitability. These data suggest that learning-induced alterations in the intrinsic excitability of neuronal ensembles is regulated dynamically across different brain areas. Furthermore, we show that changes in associative strength modulate the excitability profile of activated ensembles in the NAc shell.SIGNIFICANCE STATEMENT Sparsely distributed sets of neurons called "neuronal ensembles" encode learned associations about food and cues predictive of its availability. Widespread changes in neuronal excitability have been observed in limbic brain areas after associative learning, but little is known about the excitability changes that

  6. Nasal neuron PET imaging quantifies neuron generation and degeneration

    National Research Council Canada - National Science Library

    Van de Bittner, Genevieve C; Riley, Misha M; Cao, Luxiang; Ehses, Janina; Herrick, Scott P; Ricq, Emily L; Wey, Hsiao-Ying; O'Neill, Michael J; Ahmed, Zeshan; Murray, Tracey K; Smith, Jaclyn E; Wang, Changning; Schroeder, Frederick A; Albers, Mark W; Hooker, Jacob M

    2017-01-01

    .... Quantification of the olfactory sensory neurons (OSNs), which detect odors within the nasal cavity, would provide insight into the etiology of olfactory dysfunction associated with disease and mortality...

  7. Resonate-and-fire neurons.

    Science.gov (United States)

    Izhikevich, E M

    2001-01-01

    We suggest a simple spiking model-resonate-and-fire neuron, which is similar to the integrate-and-fire neuron except that the state variable is complex. The model provides geometric illustrations to many interesting phenomena occurring in biological neurons having subthreshold damped oscillations of membrane potential. For example, such neurons prefer a certain resonant frequency of the input that is nearly equal to their eigenfrequency, they can be excited or inhibited by a doublet (two pulses) depending on its interspike interval, and they can fire in response to an inhibitory input. All these properties could be observed in Hodgkin-Huxley-type models. We use the resonate-and-fire model to illustrate possible sensitivity of biological neurons to the fine temporal structure of the input spike train. Being an analogue of the integrate-and-fire model, the resonate-and-fire model is computationally efficient and suitable for simulations of large networks of spiking neurons.

  8. Signal transfer within a cultured asymmetric cortical neuron circuit

    Science.gov (United States)

    Isomura, Takuya; Shimba, Kenta; Takayama, Yuzo; Takeuchi, Akimasa; Kotani, Kiyoshi; Jimbo, Yasuhiko

    2015-12-01

    Objective. Simplified neuronal circuits are required for investigating information representation in nervous systems and for validating theoretical neural network models. Here, we developed patterned neuronal circuits using micro fabricated devices, comprising a micro-well array bonded to a microelectrode-array substrate. Approach. The micro-well array consisted of micrometre-scale wells connected by tunnels, all contained within a silicone slab called a micro-chamber. The design of the micro-chamber confined somata to the wells and allowed axons to grow through the tunnels bidirectionally but with a designed, unidirectional bias. We guided axons into the point of the arrow structure where one of the two tunnel entrances is located, making that the preferred direction. Main results. When rat cortical neurons were cultured in the wells, their axons grew through the tunnels and connected to neurons in adjoining wells. Unidirectional burst transfers and other asymmetric signal-propagation phenomena were observed via the substrate-embedded electrodes. Seventy-nine percent of burst transfers were in the forward direction. We also observed rapid propagation of activity from sites of local electrical stimulation, and significant effects of inhibitory synapse blockade on bursting activity. Significance. These results suggest that this simple, substrate-controlled neuronal circuit can be applied to develop in vitro models of the function of cortical microcircuits or deep neural networks, better to elucidate the laws governing the dynamics of neuronal networks.