Sample records for altered gaba levels

  1. mRNA and Protein Levels for GABA[subscript A][alpha]4, [alpha]5, [beta]1 and GABA[subscript B]R1 Receptors are Altered in Brains from Subjects with Autism (United States)

    Fatemi, S. Hossein; Reutiman, Teri J.; Folsom, Timothy D.; Rooney, Robert J.; Patel, Diven H.; Thuras, Paul D.


    We have shown altered expression of gamma-aminobutyric acid A (GABA[subscript A]) and gamma-aminobutyric acid B (GABA[subscript B]) receptors in the brains of subjects with autism. In the current study, we sought to verify our western blotting data for GABBR1 via qRT-PCR and to expand our previous work to measure mRNA and protein levels of 3…

  2. Stress-restress evokes sustained iNOS activity and altered GABA levels and NMDA receptors in rat hippocampus

    DEFF Research Database (Denmark)

    Harvey, Brian H; Oosthuizen, Frasia; Brand, Linda


    -methyl-D-aspartate (NMDA) receptor binding characteristics and GABA levels were studied in Sprague-Dawley rats 21 days after exposure to a stress-restress paradigm, using radiometric analysis, radioligand studies and high-performance liquid chromatography (HPLC) analysis with electrochemical detection, respectively...

  3. GABA and GABA receptors alterations in the primary visual cortex of concave lens-induced myopic model. (United States)

    Zhao, Wen; Bi, Ai-Ling; Xu, Chao-Li; Ye, Xiang; Chen, Mei-Qing; Wang, Xin-Ting; Zhang, Xiao-Yan; Guo, Jun-Guo; Jiang, Wen-Jun; Zhang, Jin; Bi, Hong-Sheng


    Until recently most researches on myopia mechanisms have mainly been focused on the eye ball and few investigations were explored on the upper visual pathway, such as the visual cortex. The roles of gamma-aminobutyric acid (GABA) in the retinal and in the upper visual pathway are inter-correlated. As the retinal glutamate decarboxylase (GAD), GABA, and the mRNA levels of GABA receptors increased during the concave lens induced myopia formation, however, whether GABA alterations also occurred in the visual cortex during the concave lens induction is still unknown. In the present study, using HPLC, Enzyme-Linked Immunosorbent Assay (ELISA) and Real-Time Quantitative-PCR (RT-PCR) methods, we observed the changing trends of GABA, glutamate decarboxylase (GAD), and GABA receptors in the visual cortex of concave lens-induced myopic guinea pigs. Similar to the changing patterns of retinal GABA, the concentrations of GAD, GABA and the mRNA levels of GABA receptors in the visual cortex also increased. These results indicate that the exploration on myopia mechanisms should possibly be investigated on the whole visual pathway and the detailed significance of cortical GABA alterations needs further investigation.

  4. Frontal GABA levels change during working memory. (United States)

    Michels, Lars; Martin, Ernst; Klaver, Peter; Edden, Richard; Zelaya, Fernando; Lythgoe, David J; Lüchinger, Rafael; Brandeis, Daniel; O'Gorman, Ruth L


    Functional neuroimaging metrics are thought to reflect changes in neurotransmitter flux, but changes in neurotransmitter levels have not been demonstrated in humans during a cognitive task, and the relationship between neurotransmitter dynamics and hemodynamic activity during cognition has not yet been established. We evaluate the concentration of the major inhibitory (GABA) and excitatory (glutamate + glutamine: Glx) neurotransmitters and the cerebral perfusion at rest and during a prolonged delayed match-to-sample working memory task. Resting GABA levels in the dorsolateral prefrontal cortex correlated positively with the resting perfusion and inversely with the change in perfusion during the task. Further, only GABA increased significantly during the first working memory run and then decreased continuously across subsequent task runs. The decrease of GABA over time was paralleled by a trend towards decreased reaction times and higher task accuracy. These results demonstrate a link between neurotransmitter dynamics and hemodynamic activity during working memory, indicating that functional neuroimaging metrics depend on the balance of excitation and inhibition required for cognitive processing.

  5. Frontal GABA levels change during working memory.

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    Lars Michels

    Full Text Available Functional neuroimaging metrics are thought to reflect changes in neurotransmitter flux, but changes in neurotransmitter levels have not been demonstrated in humans during a cognitive task, and the relationship between neurotransmitter dynamics and hemodynamic activity during cognition has not yet been established. We evaluate the concentration of the major inhibitory (GABA and excitatory (glutamate + glutamine: Glx neurotransmitters and the cerebral perfusion at rest and during a prolonged delayed match-to-sample working memory task. Resting GABA levels in the dorsolateral prefrontal cortex correlated positively with the resting perfusion and inversely with the change in perfusion during the task. Further, only GABA increased significantly during the first working memory run and then decreased continuously across subsequent task runs. The decrease of GABA over time was paralleled by a trend towards decreased reaction times and higher task accuracy. These results demonstrate a link between neurotransmitter dynamics and hemodynamic activity during working memory, indicating that functional neuroimaging metrics depend on the balance of excitation and inhibition required for cognitive processing.

  6. GABA level, gamma oscillation, and working memory performance in schizophrenia

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    Chi-Ming A. Chen


    Full Text Available A relationship between working memory impairment, disordered neuronal oscillations, and abnormal prefrontal GABA function has been hypothesized in schizophrenia; however, in vivo GABA measurements and gamma band neural synchrony have not yet been compared in schizophrenia. This case–control pilot study (N = 24 compared baseline and working memory task-induced neuronal oscillations acquired with high-density electroencephalograms (EEGs to GABA levels measured in vivo with magnetic resonance spectroscopy. Working memory performance, baseline GABA level in the left dorsolateral prefrontal cortex (DLPFC, and measures of gamma oscillations from EEGs at baseline and during a working memory task were obtained. A major limitation of this study is a relatively small sample size for several analyses due to the integration of diverse methodologies and participant compliance. Working memory performance was significantly lower for patients than for controls. During the working memory task, patients (n = 7 had significantly lower amplitudes in gamma oscillations than controls (n = 9. However, both at rest and across working memory stages, there were significant correlations between gamma oscillation amplitude and left DLPFC GABA level. Peak gamma frequency during the encoding stage of the working memory task (n = 16 significantly correlated with GABA level and working memory performance. Despite gamma band amplitude deficits in patients across working memory stages, both baseline and working memory-induced gamma oscillations showed strong dependence on baseline GABA levels in patients and controls. These findings suggest a critical role for GABA function in gamma band oscillations, even under conditions of system and cognitive impairments as seen in schizophrenia.

  7. [Pharmacological influences on the brain level and transport of GABA. II) Effect of various psychoactive drugs on brain level and uptake of GABA]. (United States)

    Gabana, M A; Varotto, M; Saladini, M; Zanchin, G; Battistin, L


    The effects of some psychoactive drugs on the level and uptake of GABA in the mouse brain was studied using well standardized procedures, mainely the silica-gel cromatography for determining the GABA content and the brain slices for measuring GABA uptake. It was found that levomepromazine, sulpiride, haloperidol and amytryptiline were without effects on the cerebral level of GABA; it was also found that these drugs do not influence the rates of uptake of GABA by mouse brain slices. Such results do indicate that the psychoactive drugs studied are without effects on the level and uptake of GABA in the brain.

  8. Altered gamma oscillations during pregnancy through loss of δ subunit-containing GABA(A) receptors on parvalbumin interneurons. (United States)

    Ferando, Isabella; Mody, Istvan


    Gamma (γ) oscillations (30-120 Hz), an emergent property of neuronal networks, correlate with memory, cognition and encoding. In the hippocampal CA3 region, locally generated γ oscillations emerge through feedback between inhibitory parvalbumin-positive basket cells (PV+BCs) and the principal (pyramidal) cells. PV+BCs express δ-subunit-containing GABA(A)Rs (δ-GABA(A)Rs) and NMDA receptors (NMDA-Rs) that balance the frequency of γ oscillations. Neuroactive steroids (NS), such as the progesterone-derived (3α,5α)-3-hydroxy-pregnan-20-one (allopregnanolone; ALLO), modulate the expression of δ-GABA(A)Rs and the tonic conductance they mediate. Pregnancy produces large increases in ALLO and brain-region-specific homeostatic changes in δ-GABA(A)Rs expression. Here we show that in CA3, where most PV+ interneurons (INs) express δ-GABA(A)Rs, expression of δ-GABA(A)Rs on INs diminishes during pregnancy, but reverts to control levels within 48 h postpartum. These anatomical findings were corroborated by a pregnancy-related increase in the frequency of kainate-induced CA3 γ oscillations in vitro that could be countered by the NMDA-R antagonists D-AP5 and PPDA. Mimicking the typical hormonal conditions during pregnancy by supplementing 100 nM ALLO lowered the γ frequencies to levels found in virgin or postpartum mice. Our findings show that states of altered NS levels (e.g., pregnancy) may provoke perturbations in γ oscillatory activity through direct effects on the GABAergic system, and underscore the importance of δ-GABA(A)Rs homeostatic plasticity in maintaining constant network output despite large hormonal changes. Inaccurate coupling of NS levels to δ-GABA(A)R expression may facilitate abnormal neurological and psychiatric conditions such as epilepsy, post-partum depression, and post-partum psychosis, thus providing insights into potential new treatments.

  9. Gestational changes of GABA levels and GABA binding in the human uterus

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    Erdoe, S.L.; Villanyi, P.; Laszlo, A.


    The concentrations of gamma-aminobutyric acid (GABA), the activities of L-glutamate decarboxylase and GABA-transaminase, and the nature of the sodium-independent binding of GABA were examined in uterine tissue pieces obtained surgically from pregnant and non-pregnant women. GABA concentrations were reduced, while the activity of GABA-transaminase and the specific binding of (/sup 3/H)GABA significantly increased in specimens from pregnant subjects. These findings suggest some gestation-related functional role for the GABA system in the human uterus.

  10. Altered response to benzodiazepine anxiolytics in mice lacking GABA B(1) receptors. (United States)

    Mombereau, Cedric; Kaupmann, Klemens; van der Putten, Herman; Cryan, John F


    Recently, we demonstrated that mice lacking the GABA(B(1)) subunit were more anxious than wild-type animals in several behavioural paradigms, most notably in the light-dark test. In an attempt to assess the effects of classical benzodiazepine anxiolytics on anxiety-like behaviour observed in these mice, animals were administered either chlordiazepoxide (10 mg/kg, p.o.) or diazepam (7.5 mg/kg, p.o.) prior to testing in the light-dark box. Surprisingly, in contrast with the wild-type mice, neither benzodiazepines decreased anxiety-like behaviour in GABA(B(1))(-/-) mice. These data suggest that targeted deletion of GABA(B(1)) subunit alters GABA(A) receptor function in vivo.

  11. In vivo neurochemical evidence that newly synthesised GABA activates GABA(B), but not GABA(A), receptors on dopaminergic nerve endings in the nucleus accumbens of freely moving rats

    NARCIS (Netherlands)

    Saigusa, T.; Aono, Y.; Sekino, R.; Uchida, T.; Takada, K.; Oi, Y.; Koshikawa, N.; Cools, A.R.


    GABA released from accumbal GABAergic interneurons plays an inhibitory role in the regulation of dopamine efflux through GABA(B) and GABA(A) receptors located on accumbal dopaminergic nerve endings. The cytosolic newly synthesised GABA alters vesicular GABA levels and, accordingly, the amount of GAB

  12. Antiepileptic activity of lobeline isolated from the leaf of Lobelia nicotianaefolia and its effect on brain GABA level in mice

    Institute of Scientific and Technical Information of China (English)

    Abrar M Tamboli; Rukhsana A Rub; Pinaki Ghosh; SL Bodhankar


    Objective:To investigate the anticonvulsant activity of the lobeline isolated from the Lobelia nicotianaefolia in chemoconvulsant-induced seizures and its biochemical mechanism by investigating relationship between seizure activities and altered gamma amino butyric acid (GABA) in brain of mice in Pentylenetetrazol (PTZ) seizure models. Methods:The anticonvulsant activity of the isolated lobeline (5, 10, 20 and 30 mg/kg, i.p.) was investigated in PTZ and strychnine induced seizures in mice and the effect of isolated lobeline on brain GABA level in seizures induced by PTZ. Diazepam was used as reference anticonvulsant drugs for comparison. Results:Isolated lobeline (10, 20 and 30 mg/kg, i.p.) significantly delayed and antagonized (P<0.050–0.001) the onset of PTZ-induced seizures. It also antagonized strychnine induced seizures. The mortality was also prevented in the test group of animals. In biochemical evaluation, isolated lobeline (5, 10 and 20 mg/kg, i.p.) significantly increased the brain GABA level. And at dose of 30 mg/kg GABA level showed slight decrease in PTZ model. Conclusions:In our findings, isolated lobeline (20mg/kg) exhibited potent anticonvulsant activity against PTZ induced seizures. Also a biochemical evaluation suggested significant increase in barain GABA level at 20 mg/kg i.p. of isolated lobeline. Hence, we may propose that lobeline reduces epileptic seizures by enhancing the GABA release supporting the GABAergic mechanism.

  13. Temporal development of GABA agonist induced alterations in ultrastructure and GABA receptor expression in cultured cerebellar granule cells

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    Hansen, Gert Helge; Belhage, B; Schousboe, A;


    The temporal development of the effect of THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) on the ultrastructure composition and GABA receptor expression in cerebellar granule cells was investigated by quantitative electron microscopy (morphometric analysis) and GABA binding assays...... exposed to THIP (150 microM) for 3 hr low affinity GABA receptors were induced. These findings show that the effect of THIP on the ultrastructure composition and GABA receptor expression in cultured cerebellar granule cells may be interrelated and moreover it is likely that the turn-over of GABA receptors...

  14. Sleep and GABA levels in the oral part of rat pontine reticular formation are decreased by local and systemic administration of morphine. (United States)

    Watson, C J; Lydic, R; Baghdoyan, H A


    Morphine, a mu-opioid receptor agonist, is a commonly prescribed treatment for pain. Although highly efficacious, morphine has many unwanted side effects including disruption of sleep and obtundation of wakefulness. One mechanism by which morphine alters sleep and wakefulness may be by modulating GABAergic signaling in brain regions regulating arousal, including the pontine reticular nucleus, oral part (PnO). This study used in vivo microdialysis in unanesthetized Sprague-Dawley rat to test the hypothesis that mu-opioid receptors modulate PnO GABA levels. Validation of the high performance liquid chromatographic technique used to quantify GABA was obtained by dialyzing the PnO (n=4 rats) with the GABA reuptake inhibitor nipecotic acid (500 microM). Nipecotic acid caused a 185+/-20% increase in PnO GABA levels, confirming chromatographic detection of GABA and demonstrating the existence of functional GABA transporters in rat PnO. Morphine caused a concentration-dependent decrease in PnO GABA levels (n=25 rats). Coadministration of morphine (100 microM) with naloxone (1 microM), a mu-opioid receptor antagonist, blocked the morphine-induced decrease in PnO GABA levels (n=5 rats). These results show for the first time that mu-opioid receptors in rat PnO modulate GABA levels. A second group of rats (n=6) was used to test the hypothesis that systemically administered morphine also decreases PnO GABA levels. I.v. morphine caused a significant (PPnO GABA levels relative to control i.v. infusions of saline. Finally, microinjections followed by 2 h recordings of electroencephalogram and electromyogram tested the hypothesis that PnO morphine administration disrupts sleep (n=8 rats). Morphine significantly (PPnO.

  15. Striatal and thalamic GABA level concentrations play differential roles for the modulation of response selection processes by proprioceptive information. (United States)

    Dharmadhikari, Shalmali; Ma, Ruoyun; Yeh, Chien-Lin; Stock, Ann-Kathrin; Snyder, Sandy; Zauber, S Elizabeth; Dydak, Ulrike; Beste, Christian


    The selection of appropriate responses is a complex endeavor requiring the integration of many different sources of information in fronto-striatal-thalamic circuits. An often neglected but relevant piece of information is provided by proprioceptive inputs about the current position of our limbs. This study examines the importance of striatal and thalamic GABA levels in these processes using GABA-edited magnetic resonance spectroscopy (GABA-MRS) and a Simon task featuring proprioception-induced interference in healthy subjects. As a possible model of deficits in the processing of proprioceptive information, we also included Parkinson's disease (PD) patients in this study. The results show that proprioceptive information about unusual postures complicates response selection processes in controls, but not in PD patients. The well-known deficits of PD patients in processing proprioceptive information can turn into a benefit when altered proprioceptive information would normally complicate response selection processes. Striatal and thalamic GABA levels play dissociable roles in the modulation of response selection processes by proprioceptive information: Striatal GABA levels seem to be important for the general speed of responding, most likely because striatal GABA promotes response selection. In contrast, the modulation of response conflict by proprioceptive information is closely related to thalamic GABA concentrations with higher concentration being related to a smaller response conflict effect. The most likely explanation for this finding is that the thalamus is involved in the integration of sensorimotor, attentional, and cognitive information for the purpose of response formation. Yet, this effect in the thalamus vanishes when controls and PD patients were analyzed separately.

  16. Removal of GABA(A receptor γ2 subunits from parvalbumin neurons causes wide-ranging behavioral alterations.

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    Elli Leppä

    Full Text Available We investigated the behavioral significance of fast synaptic inhibition by αβγ2-type GABA(A receptors on parvalbumin (Pv cells. The GABA(A receptor γ2 subunit gene was selectively inactivated in Pv-positive neurons by Cre/loxP recombination. The resulting Pv-Δγ2 mice were relatively healthy in the first postnatal weeks; but then as Cre started to be expressed, the mice progressively developed wide-ranging phenotypic alterations including low body weight, motor deficits and tremor, decreased anxiety levels, decreased pain sensitivity and deficient prepulse inhibition of the acoustic startle reflex and impaired spatial learning. Nevertheless, the deletion was not lethal, and mice did not show increased mortality even after one year. Autoradiography with t-butylbicyclophosphoro[(35S]thionate suggested an increased amount of GABA(A receptors with only α and β subunits in central nervous system regions that contained high levels of parvalbumin neurons. Using BAC-transgenesis, we reduced some of the Pv-Δγ2 phenotype by selectively re-expressing the wild-type γ2 subunit back into some Pv cells (reticular thalamic neurons and cerebellar Pv-positive neurons. This produced less severe impairments of motor skills and spatial learning compared with Pv-Δγ2 mice, but all other deficits remained. Our results reveal the widespread significance of fast GABAergic inhibition onto Pv-positive neurons for diverse behavioral modalities, such as motor coordination, sensorimotor integration, emotional behavior and nociception.

  17. The root-specific glutamate decarboxylase (GAD1) is essential for sustaining GABA levels in Arabidopsis. (United States)

    Bouché, Nicolas; Fait, Aaron; Zik, Moriyah; Fromm, Hillel


    In plants, as in most eukaryotes, glutamate decarboxylase catalyses the synthesis of GABA. The Arabidopsis genome contains five glutamate decarboxylase genes and one of these genes (glutamate decarboxylase1; i.e. GAD1 ) is expressed specifically in roots. By isolating and analyzing three gad1 T-DNA insertion alleles, derived from two ecotypes, we investigated the potential role of GAD1 in GABA production. We also analyzed a promoter region of the GAD1 gene and show that it confers root-specific expression when fused to reporter genes. Phenotypic analysis of the gad1 insertion mutants revealed that GABA levels in roots were drastically reduced compared with those in the wild type. The roots of the wild type contained about sevenfold more GABA than roots of the mutants. Disruption of the GAD1 gene also prevented the accumulation of GABA in roots in response to heat stress. Our results show that the root-specific calcium/calmodulin-regulated GAD1 plays a major role in GABA synthesis in plants under normal growth conditions and in response to stress.

  18. GABA-A and NMDA receptor expression is altered in the caudate but not the putamen of the postmortem brains of alcoholics.

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    Amol K Bhandage


    Full Text Available Chronic consumption of alcohol by humans has been shown to lead to impairment of executive and cognitive functions. Here we have studied the changes that take place in the dorsal striatum in post-mortem brains of alcoholics and normal controls. The results show a significant change in the expression of both the excitatory ionotropic glutamate receptor and the inhibitory GABA-A receptor subunit genes in the caudate but not the putamen of the striatum. The mRNA levels in the caudate encoding the glutamate receptor subunit GluN2A and the GABA-A receptor subunits δ, ε and ρ2 were significantly decreased whereas the GluD1, GluD2 and the GABA-A γ1 mRNA levels were significantly increased in the alcoholics as compared to controls. Interestingly in controls, 11 glutamate and 5 GABA-A receptor genes were more prominently (fold-increase varied from 1.24 to 2.91 expressed in the caudate than the putamen. We have previously shown in post-mortem samples from alcoholics that the expression level of glutamate and GABA-A receptor genes in the dorsal-lateral prefrontal cortex is similar to that of normal controls (Jin et al., 2011a;Jin et al., 2014b. This is in contrast to the present study. As the caudate is vital for automatic thinking, the results indicate that the balance between voluntary and automatic control of behaviours is altered in alcoholics. Our results suggest that there may be diminished executive control on goal-directed alcohol-seeking behaviour and, rather, a shift to greater striatal control over behaviours that may be critical in the progress of becoming an alcoholic.

  19. GABA-A and NMDA receptor subunit mRNA expression is altered in the caudate but not the putamen of the postmortem brains of alcoholics. (United States)

    Bhandage, Amol K; Jin, Zhe; Bazov, Igor; Kononenko, Olga; Bakalkin, Georgy; Korpi, Esa R; Birnir, Bryndis


    Chronic consumption of alcohol by humans has been shown to lead to impairment of executive and cognitive functions. Here, we have studied the mRNA expression of ion channel receptors for glutamate and GABA in the dorsal striatum of post-mortem brains from alcoholics (n = 29) and normal controls (n = 29), with the focus on the caudate nucleus that is associated with the frontal cortex executive functions and automatic thinking and on the putamen area that is linked to motor cortices and automatic movements. The results obtained by qPCR assay revealed significant changes in the expression of specific excitatory ionotropic glutamate and inhibitory GABA-A receptor subunit genes in the caudate but not the putamen. Thus, in the caudate we found reduced levels of mRNAs encoding the GluN2A glutamate receptor and the δ, ε, and ρ2 GABA-A receptor subunits, and increased levels of the mRNAs encoding GluD1, GluD2, and GABA-A γ1 subunits in the alcoholics as compared to controls. Interestingly in the controls, 11 glutamate and 5 GABA-A receptor genes were more prominently expressed in the caudate than the putamen (fold-increase varied from 1.24 to 2.91). Differences in gene expression patterns between the striatal regions may underlie differences in associated behavioral outputs. Our results suggest an altered balance between caudate-mediated voluntarily controlled and automatic behaviors in alcoholics, including diminished executive control on goal-directed alcohol-seeking behavior.

  20. An altered GABA-A receptor function in spinocerebellar ataxia type 6 and familial hemiplegic migraine type 1 associated with the CACNA1A gene mutation

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    Satoshi Kono


    General significance: An altered GABA-A receptor function has previously been reported in models of inherited murine cerebellar ataxia caused by a mutation in the CACNA1A gene. This study showed novel clinical characteristics of alteration in the GABA-A receptor in vivo, which may provide clinical evidence indicating a pathological mechanism common to neurological disorders associated with CACNA1A gene mutation.

  1. Effects of Yoga Versus Walking on Mood, Anxiety, and Brain GABA Levels: A Randomized Controlled MRS Study (United States)

    Whitfield, Theodore H.; Owen, Liz; Rein, Tasha; Karri, Surya K.; Yakhkind, Aleksandra; Perlmutter, Ruth; Prescot, Andrew; Renshaw, Perry F.; Ciraulo, Domenic A.; Jensen, J. Eric


    Abstract Objectives Yoga and exercise have beneficial effects on mood and anxiety. γ-Aminobutyric acid (GABA)-ergic activity is reduced in mood and anxiety disorders. The practice of yoga postures is associated with increased brain GABA levels. This study addresses the question of whether changes in mood, anxiety, and GABA levels are specific to yoga or related to physical activity. Methods Healthy subjects with no significant medical/psychiatric disorders were randomized to yoga or a metabolically matched walking intervention for 60 minutes 3 times a week for 12 weeks. Mood and anxiety scales were taken at weeks 0, 4, 8, 12, and before each magnetic resonance spectroscopy scan. Scan 1 was at baseline. Scan 2, obtained after the 12-week intervention, was followed by a 60-minute yoga or walking intervention, which was immediately followed by Scan 3. Results The yoga subjects (n = 19) reported greater improvement in mood and greater decreases in anxiety than the walking group (n = 15). There were positive correlations between improved mood and decreased anxiety and thalamic GABA levels. The yoga group had positive correlations between changes in mood scales and changes in GABA levels. Conclusions The 12-week yoga intervention was associated with greater improvements in mood and anxiety than a metabolically matched walking exercise. This is the first study to demonstrate that increased thalamic GABA levels are associated with improved mood and decreased anxiety. It is also the first time that a behavioral intervention (i.e., yoga postures) has been associated with a positive correlation between acute increases in thalamic GABA levels and improvements in mood and anxiety scales. Given that pharmacologic agents that increase the activity of the GABA system are prescribed to improve mood and decrease anxiety, the reported correlations are in the expected direction. The possible role of GABA in mediating the beneficial effects of yoga on mood and anxiety warrants

  2. Seizure-induced alterations in fast-spiking basket cell GABA currents modulate frequency and coherence of gamma oscillation in network simulations

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    Proddutur, Archana; Yu, Jiandong; Elgammal, Fatima S. [Department of Neurology and Neurosciences, New Jersey Medical School, Rutgers, Newark, New Jersey 07103 (United States); Santhakumar, Vijayalakshmi, E-mail: [Department of Neurology and Neurosciences, New Jersey Medical School, Rutgers, Newark, New Jersey 07103 (United States); Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, Newark, New Jersey 07103 (United States)


    Gamma frequency oscillations have been proposed to contribute to memory formation and retrieval. Fast-spiking basket cells (FS-BCs) are known to underlie development of gamma oscillations. Fast, high amplitude GABA synapses and gap junctions have been suggested to contribute to gamma oscillations in FS-BC networks. Recently, we identified that, apart from GABAergic synapses, FS-BCs in the hippocampal dentate gyrus have GABAergic currents mediated by extrasynaptic receptors. Our experimental studies demonstrated two specific changes in FS-BC GABA currents following experimental seizures [Yu et al., J. Neurophysiol. 109, 1746 (2013)]: increase in the magnitude of extrasynaptic (tonic) GABA currents and a depolarizing shift in GABA reversal potential (E{sub GABA}). Here, we use homogeneous networks of a biophysically based model of FS-BCs to examine how the presence of extrasynaptic GABA conductance (g{sub GABA-extra}) and experimentally identified, seizure-induced changes in g{sub GABA-extra} and E{sub GABA} influence network activity. Networks of FS-BCs interconnected by fast GABAergic synapses developed synchronous firing in the dentate gamma frequency range (40–100 Hz). Systematic investigation revealed that the biologically realistic range of 30 to 40 connections between FS-BCs resulted in greater coherence in the gamma frequency range when networks were activated by Poisson-distributed dendritic synaptic inputs rather than by homogeneous somatic current injections, which were balanced for FS-BC firing frequency in unconnected networks. Distance-dependent conduction delay enhanced coherence in networks with 30–40 FS-BC interconnections while inclusion of gap junctional conductance had a modest effect on coherence. In networks activated by somatic current injections resulting in heterogeneous FS-BC firing, increasing g{sub GABA-extra} reduced the frequency and coherence of FS-BC firing when E{sub GABA} was shunting (−74 mV), but failed to alter average

  3. Genetic manipulation of the γ-aminobutyric acid (GABA) shunt in rice: overexpression of truncated glutamate decarboxylase (GAD2) and knockdown of γ-aminobutyric acid transaminase (GABA-T) lead to sustained and high levels of GABA accumulation in rice kernels. (United States)

    Shimajiri, Yasuka; Oonishi, Takayuki; Ozaki, Kae; Kainou, Kumiko; Akama, Kazuhito


    Gamma-aminobutyric acid (GABA) is a non-protein amino acid commonly present in all organisms. Because cellular levels of GABA in plants are mainly regulated by synthesis (glutamate decarboxylase, GAD) and catabolism (GABA-transaminase, GABA-T), we attempted seed-specific manipulation of the GABA shunt to achieve stable GABA accumulation in rice. A truncated GAD2 sequence, one of five GAD genes, controlled by the glutelin (GluB-1) or rice embryo globulin promoters (REG) and GABA-T-based trigger sequences in RNA interference (RNAi) cassettes controlled by one of these promoters as well, was introduced into rice (cv. Koshihikari) to establish stable transgenic lines under herbicide selection using pyriminobac. T₁ and T₂ generations of rice lines displayed high GABA concentrations (2-100 mg/100 g grain). In analyses of two selected lines from the T₃ generation, there was a strong correlation between GABA level and the expression of truncated GAD2, whereas the inhibitory effect of GABA-T expression was relatively weak. In these two lines both with two T-DNA copies, their starch, amylose, and protein levels were slightly lower than non-transformed cv. Koshihikari. Free amino acid analysis of mature kernels of these lines demonstrated elevated levels of GABA (75-350 mg/100 g polished rice) and also high levels of several amino acids, such as Ala, Ser, and Val. Because these lines of seeds could sustain their GABA content after harvest (up to 6 months), the strategy in this study could lead to the accumulation GABA and for these to be sustained in the edible parts.


    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 ...

  5. Seizure-induced alterations in fast-spiking basket cell GABA currents modulate frequency and coherence of gamma oscillation in network simulations (United States)

    Proddutur, Archana; Yu, Jiandong; Elgammal, Fatima S.; Santhakumar, Vijayalakshmi


    Gamma frequency oscillations have been proposed to contribute to memory formation and retrieval. Fast-spiking basket cells (FS-BCs) are known to underlie development of gamma oscillations. Fast, high amplitude GABA synapses and gap junctions have been suggested to contribute to gamma oscillations in FS-BC networks. Recently, we identified that, apart from GABAergic synapses, FS-BCs in the hippocampal dentate gyrus have GABAergic currents mediated by extrasynaptic receptors. Our experimental studies demonstrated two specific changes in FS-BC GABA currents following experimental seizures [Yu et al., J. Neurophysiol. 109, 1746 (2013)]: increase in the magnitude of extrasynaptic (tonic) GABA currents and a depolarizing shift in GABA reversal potential (EGABA). Here, we use homogeneous networks of a biophysically based model of FS-BCs to examine how the presence of extrasynaptic GABA conductance (gGABA-extra) and experimentally identified, seizure-induced changes in gGABA-extra and EGABA influence network activity. Networks of FS-BCs interconnected by fast GABAergic synapses developed synchronous firing in the dentate gamma frequency range (40-100 Hz). Systematic investigation revealed that the biologically realistic range of 30 to 40 connections between FS-BCs resulted in greater coherence in the gamma frequency range when networks were activated by Poisson-distributed dendritic synaptic inputs rather than by homogeneous somatic current injections, which were balanced for FS-BC firing frequency in unconnected networks. Distance-dependent conduction delay enhanced coherence in networks with 30-40 FS-BC interconnections while inclusion of gap junctional conductance had a modest effect on coherence. In networks activated by somatic current injections resulting in heterogeneous FS-BC firing, increasing gGABA-extra reduced the frequency and coherence of FS-BC firing when EGABA was shunting (-74 mV), but failed to alter average FS-BC frequency when EGABA was depolarizing

  6. Multi-regional investigation of the relationship between functional MRI blood oxygenation level dependent (BOLD activation and GABA concentration.

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    Ashley D Harris

    Full Text Available Several recent studies have reported an inter-individual correlation between regional GABA concentration, as measured by MRS, and the amplitude of the functional blood oxygenation level dependent (BOLD response in the same region. In this study, we set out to investigate whether this coupling generalizes across cortex. In 18 healthy participants, we performed edited MRS measurements of GABA and BOLD-fMRI experiments using regionally related activation paradigms. Regions and tasks were the: occipital cortex with a visual grating stimulus; auditory cortex with a white noise stimulus; sensorimotor cortex with a finger-tapping task; frontal eye field with a saccade task; and dorsolateral prefrontal cortex with a working memory task. In contrast to the prior literature, no correlation between GABA concentration and BOLD activation was detected in any region. The origin of this discrepancy is not clear. Subtle differences in study design or insufficient power may cause differing results; these and other potential reasons for the discrepant results are discussed. This negative result, although it should be interpreted with caution, has a larger sample size than prior positive results, and suggests that the relationship between GABA and the BOLD response may be more complex than previously thought.

  7. IGF-1 Restores Visual Cortex Plasticity in Adult Life by Reducing Local GABA Levels

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    José Fernando Maya-Vetencourt


    Full Text Available The central nervous system architecture is markedly modified by sensory experience during early life, but a decline of plasticity occurs with age. Recent studies have challenged this dogma providing evidence that both pharmacological treatments and paradigms based on the manipulation of environmental stimulation levels can be successfully employed as strategies for enhancing plasticity in the adult nervous system. Insulin-like growth factor 1 (IGF-1 is a peptide implicated in prenatal and postnatal phases of brain development such as neurogenesis, neuronal differentiation, synaptogenesis, and experience-dependent plasticity. Here, using the visual system as a paradigmatic model, we report that IGF-1 reactivates neural plasticity in the adult brain. Exogenous administration of IGF-1 in the adult visual cortex, indeed, restores the susceptibility of cortical neurons to monocular deprivation and promotes the recovery of normal visual functions in adult amblyopic animals. These effects were accompanied by a marked reduction of intracortical GABA levels. Moreover, we show that a transitory increase of IGF-1 expression is associated to the plasticity reinstatement induced by environmental enrichment (EE and that blocking IGF-1 action by means of the IGF-1 receptor antagonist JB1 prevents EE effects on plasticity processes.

  8. GABA concentration and GABAergic neuron populations in limbic areas are differentially altered by brain serotonin deficiency in Tph2 knockout mice. (United States)

    Waider, Jonas; Proft, Florian; Langlhofer, Georg; Asan, Esther; Lesch, Klaus-Peter; Gutknecht, Lise


    While tryptophan hydroxylase-2 (Tph2) null mutant (Tph2(-/-)) mice are completely deficient in brain serotonin (5-HT) synthesis, the formation of serotonergic neurons and pathfinding of their projections are not impaired. However, 5-HT deficiency, during development and in the adult, might affect morphological and functional parameters of other neural systems. To assess the influence of 5-HT deficiency on γ-amino butyric acid (GABA) systems, we carried out measurements of GABA concentrations in limbic brain regions of adult male wildtype (wt), heterozygous (Tph2(+/-)) and Tph2(-/-) mice. In addition, unbiased stereological estimation of GABAergic interneuron numbers and density was performed in subregions of amygdala and hippocampus. Amygdala and prefrontal cortex displayed significantly increased and decreased GABA concentrations, respectively, exclusively in Tph2(+/-) mice while no changes were detected between Tph2(-/-) and wt mice. In contrast, in the hippocampus, increased GABA concentrations were found in Tph2(-/-) mice. While total cell density in the anterior basolateral amygdala did not differ between genotypes, the number and density of the GABAergic interneurons were significantly decreased in Tph2(-/-) mice, with the group of parvalbumin (PV)-immunoreactive (ir) interneurons contributing somewhat less to the decrease than that of non-PV-ir GABAergic interneurons. Major morphological changes were also absent in the dorsal hippocampus, and only a trend toward reduced density of PV-ir cells was observed in the CA3 region of Tph2(-/-) mice. Our findings are the first to document that life-long reduction or complete lack of brain 5-HT transmission causes differential changes of GABA systems in limbic regions which are key players in emotional learning and memory processes. The changes likely reflect a combination of developmental alterations and functional adaptations of emotion circuits to balance the lack of 5-HT, and may underlie altered emotional

  9. GABA-shunt enzymes activity in GH3 cells with reduced level of PMCA2 or PMCA3 isoform

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    Kowalski, Antoni, E-mail: [Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str., 92-215 Lodz (Poland); Zylinska, Ludmila, E-mail: [Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str., 92-215 Lodz (Poland); Boczek, Tomasz, E-mail: [Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str., 92-215 Lodz (Poland); Rebas, Elzbieta, E-mail: [Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str., 92-215 Lodz (Poland)


    Highlights: {yields} Suppression of PMCA2 or PMCA3 slows down proliferation of GH3 cells. {yields} PMCA2 suppression lowers the activity of GABA-shunt enzymes. {yields} PMCA3 suppression increases the expression of glutamate decarboxylase 65. {yields} PMCA2 and PMCA3 function appears to be linked to regulation of GABA metabolism. -- Abstract: GABA ({gamma}-aminobutyric acid) is important neurotransmitter and regulator of endocrine functions. Its metabolism involves three enzymes: glutamate decarboxylase (GAD65 and GAD67), GABA aminotransferase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH). As many cellular processes GABA turnover can depend on calcium homeostasis, which is maintained by plasma membrane calcium ATPases (PMCAs). In excitable cells PMCA2 and PMCA3 isoforms are particularly important. In this study we focused on GABA-metabolizing enzymes expression and activity in rat anterior pituitary GH3 cells with suppressed expression of PMCA2 or PMCA3. We observed that PMCA3-reduced cells have increased GAD65 expression. Suppression of PMCA2 caused a decrease in total GAD and GABA-T activity. These results indicate that PMCA2 and PMCA3 presence may be an important regulatory factor in GABA metabolism. Results suggest that PMCA2 and PMCA3 function is rather related to regulation of GABA synthesis and degradation than supplying cells with metabolites, which can be potentially energetic source.

  10. Effects of GABA agonists on body temperature regulation in GABA(B(1))-/- mice. (United States)

    Quéva, Christophe; Bremner-Danielsen, Marianne; Edlund, Anders; Ekstrand, A Jonas; Elg, Susanne; Erickson, Sven; Johansson, Thore; Lehmann, Anders; Mattsson, Jan P


    1. Activation of GABA(B) receptors evokes hypothermia in wildtype (GABA(B(1))+/+) but not in GABA(B) receptor knockout (GABA(B(1))-/-) mice. The aim of the present study was to determine the hypothermic and behavioural effects of the putative GABA(B) receptor agonist gamma-hydroxybutyrate (GHB), and of the GABA(A) receptor agonist muscimol. In addition, basal body temperature was determined in GABA(B(1))+/+, GABA(B(1))+/- and GABA(B(1))-/- mice. 2. GABA(B(1))-/- mice were generated by homologous recombination in embryonic stem cells. Correct gene targeting was assessed by Southern blotting, PCR and Western blotting. GABA(B) receptor-binding sites were quantified with radioligand binding. Measurement of body temperature was done using subcutaneous temperature-sensitive chips, and behavioural changes after drug administration were scored according to a semiquantitative scale. 3. GABA(B(1))-/- mice had a short lifespan, probably caused by generalised seizure activity. No histopathological or blood chemistry changes were seen, but the expression of GABA(B(2)) receptor protein was below the detection limit in brains from GABA(B(1))-/- mice, in the absence of changes in mRNA levels. 4. GABA(B) receptor-binding sites were absent in brain membranes from GABA(B(1))-/- mice. 5. GABA(B(1))-/- mice were hypothermic by approximately 1 degrees C compared to GABA(B(1))+/+ and GABA(B(1))+/- mice. 6. Injection of baclofen (9.6 mg kg-1) produced a large reduction in body temperature and behavioural effects in GABA(B(1))+/+ and in GABA(B(1))+/- mice, but GABA(B(1))-/- mice were unaffected. The same pattern was seen after administration of GHB (400 mg kg-1). The GABA(A) receptor agonist muscimol (2 mg kg-1), on the other hand, produced a more pronounced hypothermia in GABA(B(1))-/-mice. In GABA(B(1))+/+ and GABA(B(1))+/- mice, muscimol induced sedation and reduced locomotor activity. However, when given to GABA(B(1))-/- mice, muscimol triggered periods of intense jumping and wild

  11. Dynamics of epileptic activity in a peculiar case of childhood absence epilepsy and correlation with thalamic levels of GABA

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    Alberto Leal


    Significance: In a clinical case of CAE with EEG and fMRI-BOLD manifestations restricted to one hemisphere, we found an associated increase in thalamic GABA concentration consistent with a role for this abnormality in human CAE.

  12. Depolarizing actions of GABA in immature neurons depend neither on ketone bodies nor on pyruvate. (United States)

    Tyzio, Roman; Allene, Camille; Nardou, Romain; Picardo, Michel A; Yamamoto, Sumii; Sivakumaran, Sudhir; Caiati, Maddalena D; Rheims, Sylvain; Minlebaev, Marat; Milh, Mathieu; Ferré, Pascal; Khazipov, Rustem; Romette, Jean-Louis; Lorquin, Jean; Cossart, Rosa; Khalilov, Ilgam; Nehlig, Astrid; Cherubini, Enrico; Ben-Ari, Yehezkel


    GABA depolarizes immature neurons because of a high [Cl(-)](i) and orchestrates giant depolarizing potential (GDP) generation. Zilberter and coworkers (Rheims et al., 2009; Holmgren et al., 2010) showed recently that the ketone body metabolite DL-3-hydroxybutyrate (DL-BHB) (4 mM), lactate (4 mM), or pyruvate (5 mM) shifted GABA actions to hyperpolarizing, suggesting that the depolarizing effects of GABA are attributable to inadequate energy supply when glucose is the sole energy source. We now report that, in rat pups (postnatal days 4-7), plasma D-BHB, lactate, and pyruvate levels are 0.9, 1.5, and 0.12 mM, respectively. Then, we show that DL-BHB (4 mM) and pyruvate (200 μM) do not affect (i) the driving force for GABA(A) receptor-mediated currents (DF(GABA)) in cell-attached single-channel recordings, (2) the resting membrane potential and reversal potential of synaptic GABA(A) receptor-mediated responses in perforated patch recordings, (3) the action potentials triggered by focal GABA applications, or (4) the GDPs determined with electrophysiological recordings and dynamic two-photon calcium imaging. Only very high nonphysiological concentrations of pyruvate (5 mM) reduced DF(GABA) and blocked GDPs. Therefore, DL-BHB does not alter GABA signals even at the high concentrations used by Zilberter and colleagues, whereas pyruvate requires exceedingly high nonphysiological concentrations to exert an effect. There is no need to alter conventional glucose enriched artificial CSF to investigate GABA signals in the developing brain.

  13. GABA B receptor subunit expression in glia. (United States)

    Charles, K J; Deuchars, J; Davies, C H; Pangalos, M N


    GABA(B) receptor subunits are widely expressed on neurons throughout the CNS, at both pre- and postsynaptic sites, where they mediate the late, slow component of the inhibitory response to the major inhibitory neurotransmitter GABA. The existence of functional GABA(B) receptors on nonneuronal cells has been reported previously, although the molecular composition of these receptors has not yet been described. Here we demonstrate for the first time, using immunohistochemistry the expression of GABA(B1a), GABA(B1b), and GABA(B2) on nonneuronal cells of the rat CNS. All three principle GABA(B) receptor subunits were expressed on these cells irrespective of whether they had been cultured or found within brain tissue sections. At the ultrastructural level GABA(B) receptor subunits were expressed on astrocytic processes surrounding both symmetrical and assymetrical synapses in the CA1 subregion of the hippocampus. In addition, GABA(B1a), GABA(B1b), and GABA(B2) receptor subunits were expressed on activated microglia in culture but were not found on myelin forming oligodendrocytes in the white matter of rat spinal cord. Together these data demonstrate that the obligate subunits of functional GABA(B) receptors are expressed in astrocytes and microglia in the rat CNS.

  14. Behavioral deficit and decreased GABA receptor functional regulation in the cerebellum of epileptic rats: effect of Bacopa monnieri and bacoside A. (United States)

    Mathew, Jobin; Peeyush Kumar, T; Khan, Reas S; Paulose, C S


    In the present study, the effects of Bacopa monnieri and its active component, bacoside A, on motor deficit and alterations of GABA receptor functional regulation in the cerebellum of epileptic rats were investigated. Scatchard analysis of [(3)H]GABA and [(3)H]bicuculline in the cerebellum of epileptic rats revealed a significant decrease in B(max) compared with control. Real-time polymerase chain reaction amplification of GABA(A) receptor subunits-GABA(Aalpha1), GABA(Aalpha5,) and GABA(Adelta)-was downregulated (Pbacoside A reversed these changes to near-control levels. Our results suggest that changes in GABAergic activity, motor learning, and memory deficit are induced by the occurrence of repetitive seizures. Treatment with B. monnieri and bacoside A prevents the occurrence of seizures thereby reducing the impairment of GABAergic activity, motor learning, and memory deficit.

  15. Impulsivity and Aggression in Female BPD and ADHD Patients: Association with ACC Glutamate and GABA Concentrations. (United States)

    Ende, Gabriele; Cackowski, Sylvia; Van Eijk, Julia; Sack, Markus; Demirakca, Traute; Kleindienst, Nikolaus; Bohus, Martin; Sobanski, Esther; Krause-Utz, Annegret; Schmahl, Christian


    Borderline personality disorder (BPD) and attention-deficit-hyperactivity disorder (ADHD) are both characterized by high impulsivity and difficulties in controlling anger and aggression. In BPD, comorbid ADHD may further increase impulsivity. For both disorders, altered MR spectroscopy levels of the neurotransmitters glutamate and GABA as well as some correlations with impulsivity were previously reported. The objective of this study was to investigate the neurotransmitters glutamate and GABA in relation to impulsivity and aggression as expressed in the anterior cingulate cortex (ACC) in groups of female patients with BPD and ADHD, respectively. Associations of glutamate and GABA levels with further BPD (symptom severity) and ADHD aspects (hyperactivity and inattention) were exploratively evaluated. 1H MR spectra were acquired at 3T to determine glutamate to total creatine ratios (Glu/tCr) and GABA levels from the ACC in a BPD group (n=26), an ADHD group (n=22), and a healthy control (HC) group (n=30); all participants were females. Both patient groups showed higher scores on self-reported impulsivity, anger, and aggression compared with HCs. ACC GABA levels were significantly lower in ADHD than HC. Although measures of impulsivity were positively related to glutamate and negatively to GABA, for aggression only a negative correlation with GABA could be demonstrated. These data provide human in vivo evidence for the role of ACC Glu/tCr and GABA in impulsivity and aggression. If distinct associations of Glu/tCr and GABA for BPD and ADHD can be confirmed in future studies, this might yield implications for more specific pharmacological treatments.

  16. Cortical kindling induces elevated levels of AMPA and GABA receptor subunit mRNA within the amygdala/piriform region and is associated with behavioral changes in the rat. (United States)

    Henderson, Amy K; Galic, Michael A; Teskey, G Campbell


    Cortical kindling causes alterations within the motor cortex and results in long-standing motor deficits. Less attention has been directed to other regions that also participate in the epileptiform activity. We examined if cortical kindling could induce changes in excitatory and inhibitory receptor subunit mRNA in the amygdala/piriform regions and if such changes are associated with behavioral deficits. After cortical kindling, amygdala/piriform regions were dissected to analyze mRNA levels of NMDA, AMPA, and GABA receptor subunits using reverse transcription polymerase chain reaction, or rats were subjected to a series of behavioral tests. Kindled rats had significantly greater amounts of GluR1 and GluR2 AMPA receptor mRNA, and alpha1 and alpha2 GABA receptor subunit mRNA, compared with sham controls, which was associated with greater anxiety-like behaviors in the elevated plus maze and reduced freezing behaviors in the fear conditioning task. In summary, cortical kindling produces dynamic receptor subunit changes in regions in addition to the seizure focus.

  17. Brain GABA levels across psychiatric disorders : A systematic literature review and meta-analysis of 1H-MRS studies

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    Schür, Remmelt R.; Draisma, Luc W R; Wijnen, Jannie P.; Boks, Marco P.; Koevoets, Martijn G J C; Joëls, Marian; Klomp, Dennis W.; Kahn, René S.; Vinkers, Christiaan H.


    The inhibitory gamma-aminobutyric acid (GABA) system is involved in the etiology of most psychiatric disorders, including schizophrenia, autism spectrum disorder (ASD) and major depressive disorder (MDD). It is therefore not surprising that proton magnetic resonance spectroscopy (1H-MRS) is increasi

  18. Motor alterations induced by chronic 4-aminopyridine infusion in the spinal cord in vivo: role of glutamate and GABA receptors

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    Rafael eLazo-Gómez


    Full Text Available Motor neuron degeneration is the pathological hallmark of motor neuron diseases, a group of neurodegenerative disorders clinically manifested as muscle fasciculations and hyperreflexia, followed by paralysis, respiratory failure and death. Ample evidence supports a role of glutamate-mediated excitotoxicity in motor death. In previous work we showed that stimulation of glutamate release from nerve endings by perfusion of the K+-channel blocker 4-aminopyridine (4-AP in the rat hippocampus induces seizures and neurodegeneration, and that AMPA insusion in the spinal cord produces paralysis and motor neuron death. On these bases, in this work we have tested the effect of the chronic infusion of 4-AP in the spinal cord, using implanted osmotic minipumps, on motor activity and on motor neuron survival, and the mechanisms underlying this effect. 4-AP produced muscle fasciculations and motor deficits assessed in two motor tests, which start 2-3 h after the implant, which ameliorated spontaneously within 6-7 days, but no neurodegeneration. These effects were prevented by both AMPA and NMDA receptors blockers. The role of GABAA receptors was also explored, and we found that chronic infusion of bicuculline induced moderate motor neuron degeneration and enhanced the hyperexcitation produced by 4-AP. Unexpectedly, the GABAAR agonist muscimol also induced motor deficits and failed to prevent the MN death induced by AMPA. We conclude that motor alterations induced by chronic 4-AP infusion in the spinal cord in vivo is due to ionotropic glutamate receptor overactivation and that blockade of GABAergic neurotransmission induces motor neuron death under chronic conditions. These results shed light on the role of glutamatergic and GABAergic neurotransmission in the regulation of motor neuron excitability in the spinal cord.

  19. Neuromodulatory properties of fluorescent carbon dots: effect on exocytotic release, uptake and ambient level of glutamate and GABA in brain nerve terminals. (United States)

    Borisova, Tatiana; Nazarova, Anastasia; Dekaliuk, Mariia; Krisanova, Natalia; Pozdnyakova, Natalia; Borysov, Arsenii; Sivko, Roman; Demchenko, Alexander P


    Carbon dots (C-dots), a recently discovered class of fluorescent nano-sized particles with pure carbon core, have great bioanalytical potential. Neuroactive properties of fluorescent C-dots obtained from β-alanine by microwave heating were assessed based on the analysis of their effects on the key characteristics of GABA- and glutamatergic neurotransmission in isolated rat brain nerve terminals. It was found that C-dots (40-800 μg/ml) in dose-dependent manner: (1) decreased exocytotic release of [(3)H]GABA and L-[(14)C]glutamate; (2) reduced acidification of synaptic vesicles; (3) attenuated the initial velocity of Na(+)-dependent transporter-mediated uptake of [(3)H]GABA and L-[(14)C]glutamate; (4) increased the ambient level of the neurotransmitters, nevertheless (5) did not change significantly the potential of the plasma membrane of nerve terminals. Almost complete suppression of exocytotic release of the neurotransmitters was caused by C-dots at a concentration of 800 μg/ml. Fluorescent and neuromodulatory features combined in C-dots create base for their potential usage for labeling and visualization of key processes in nerve terminals, and also in theranostics. In addition, natural presence of carbon-containing nanoparticles in the human food chain and in the air may provoke the development of neurologic consequences.

  20. GABA[subscript A] Receptor Downregulation in Brains of Subjects with Autism (United States)

    Fatemi, S. Hossein; Reutiman, Teri J.; Folsom, Timothy D.; Thuras, Paul D.


    Gamma-aminobutyric acid A (GABA[subscript A]) receptors are ligand-gated ion channels responsible for mediation of fast inhibitory action of GABA in the brain. Preliminary reports have demonstrated altered expression of GABA receptors in the brains of subjects with autism suggesting GABA/glutamate system dysregulation. We investigated the…

  1. Multiple facets of GABAergic neurons and synapses: multiple fates of GABA signalling in epilepsies. (United States)

    Cossart, Rosa; Bernard, Christophe; Ben-Ari, Yehezkel


    Because blocking GABAergic neurotransmission in control tissue generates seizures and because GABA boosters control epilepsy in many patients, studies on epilepsies have been dominated by the axiom that seizures are generated by a failure of GABA-mediated inhibition. However, GABAergic interneurons and synapses are heterogeneous and have many roles that go beyond the straightforward concept of "inhibition of the target". Operation of such a diversified system cannot be ascribed to a single mechanism. In epileptic tissue, GABAergic networks undergo complex rewiring at the anatomical, physiological and functional levels; GABAergic synapses are still operative but show unique features, including excitatory effects. Therefore, inhibition is not a uniform notion and the concept of "failure" of inhibition in epilepsies must be reassessed. Seizures are not generated in a normal circuit in which GABA-mediated inhibition is simply impaired, but in a profoundly rewired network in which several properties of GABA function are altered. This review is part of the TINS Interneuron Diversity series.

  2. Chronic flumazenil alters GABA(A) receptor subunit mRNA expression, translation product assembly and channel function in neuronal cultures. (United States)

    Zheng, T M; Caruncho, H J; Zhu, W J; Vicini, S; Ikonomovic, S; Grayson, D R; Costa, E


    Flumazenil competitively blocks the pharmacological effects of both positive and negative allosteric modulators acting at the benzodiazepine binding sites of gamma-aminobutyric acid (GABA(A)) receptors. Using quantitative reverse transcription polymerase chain reaction, label-fracture immunocytochemistry and whole-cell patch-clamp recordings, we determined changes in the contents of selected GABA(A) receptor subunit mRNA(s), in their translation products and in the electrophysiological characteristics of the receptor channels in cultured cerebellar granule cells treated daily with flumazenil (10 microM) for 4 days in vitro. The contents of the alpha1 and alpha6 receptor subunit mRNAs were significantly increased in the flumazenil-treated group as compared with the dimethyl sulfoxide vehicle-treated control group, whereas there were no significant differences in the absolute amounts of the beta2, beta3, gamma2S, gamma2L++ + and delta receptor subunit mRNAs. The gold immunolabeling densities of the alpha1 and delta receptor subunits were significantly increased, whereas those of the alpha6, beta2/beta3 and gamma2 receptor subunits were decreased. Double-immunolabeling experiments using 5- and 10-nm gold particles suggest that after chronic flumazenil treatment, receptor subunit assemblies containing the alpha1/gamma2 and alpha6/delta subunits may be replaced by a receptor assembly containing the alpha1/delta subunits. The GABA potency in eliciting Cl- channel activity decreased significantly, as indicated by the elevated EC50 values, and the positive modulation of GABA action by diazepam also decreased. These results suggest that flumazenil, perhaps by blocking the action of endogenous allosteric modulators of GABA(A) receptors, may trigger a change in the expression and assembly of the subunits of the GABA(A) receptor. This implies that there might be a dynamic state in the regulation of GABA(A) receptor structure.

  3. Comparative immunohistochemical localisation of GABA(B1a), GABA(B1b) and GABA(B2) subunits in rat brain, spinal cord and dorsal root ganglion. (United States)

    Charles, K J; Evans, M L; Robbins, M J; Calver, A R; Leslie, R A; Pangalos, M N


    GABA(B) receptors are G-protein-coupled receptors mediating the slow onset and prolonged synaptic actions of GABA in the CNS. The recent cloning of two genes, GABA(B1) and GABA(B2), has revealed a novel requirement for GABA(B) receptor signalling. Studies have demonstrated that the two receptor subunits associate as a GABA(B1)/GABA(B2) heterodimer to form a functional GABA(B) receptor. In this study we have developed polyclonal antisera specific to two splice variants of the GABA(B1) subunit, GABA(B1a) and GABA(B1b), as well as an antiserum to the GABA(B2) subunit. Using affinity-purified antibodies derived from these antisera we have mapped out the distribution profile of each subunit in rat brain, spinal cord and dorsal root ganglion. In brain the highest areas of GABA(B1a), GABA(B1b) and GABA(B2) subunit expression were found in neocortex, hippocampus, thalamus, cerebellum and habenula. In spinal cord, GABA(B1) and GABA(B2) subunits were expressed in the superficial layers of the dorsal horn, as well as in motor neurones in the deeper layers of the ventral horn. GABA(B) receptor subunit immunoreactivity in dorsal root ganglion suggested that expression of GABA(B1b) was restricted to the large diameter neurones, in contrast to GABA(B1a) and GABA(B2) subunits which were expressed in both large and small diameter neurones. Although expression levels of GABA(B1) and GABA(B2) subunits varied we found no areas in which GABA(B1) was expressed in the absence of GABA(B2). This suggests that most, if not all, GABA(B1) immunoreactivity may represent functional GABA(B) receptors. Although our data are in general agreement with functional studies, some discrepancies in GABA(B1) subunit expression occurred with respect to other immunohistochemical studies. Overall our data suggest that GABA(B) receptors are widely expressed throughout the brain and spinal cord, and that GABA(B1a) and GABA(B1b) subunits can associate with GABA(B2) to form both pre- and post-synaptic receptors.

  4. Effect of timing and duration of salt treatment during growth of a fragrant rice variety on yield and 2-acetyl-1-pyrroline, proline, and GABA Levels. (United States)

    Poonlaphdecha, Janchai; Maraval, Isabelle; Roques, Sandrine; Audebert, Alain; Boulanger, Renaud; Bry, Xavier; Gunata, Ziya


    In greenhouse experiments, Aychade, a fragrant rice variety, was grown under one level of salt solution (EC of 3800 ± 400 μS·cm(-1)) sufficient to induce salt stress in rice. Timing and duration of salt solution application varied according to the growth stages. 2-Acetyl-1-pyrroline (2AP), a characteristic flavor compound of fragrant rice as well as biogenetically related compounds, proline, and γ-aminobutyric acid (GABA) were quantified. Salt treatments induced 2AP synthesis in the leaves, but the increase was often higher in the vegetative phase. This increase was correlated with proline level but not with that of GABA. Interestingly the grains from all the salt treated plants contained significantly higher levels of 2AP (733-998 μg·kg(-1)) than those from the control (592 μg·kg(-1)). The highest 2AP synthesis occurred when the plants were subjected to salt treatment during whole vegetative or reproductive phases. However in the latter case crop yield decreased significantly.

  5. Suppression of γ-aminobutyric acid (GABA) transaminases induces prominent GABA accumulation, dwarfism and infertility in the tomato (Solanum lycopersicum L.). (United States)

    Koike, Satoshi; Matsukura, Chiaki; Takayama, Mariko; Asamizu, Erika; Ezura, Hiroshi


    Tomatoes accumulate γ-aminobutyric acid (GABA) at high levels in the immature fruits. GABA is rapidly converted to succinate during fruit ripening through the activities of GABA transaminase (GABA-T) and succinate semialdehyde dehydrogenase (SSADH). Although three genes encoding GABA-T and both pyruvate- and α-ketoglutarate-dependent GABA-T activities have been detected in tomato fruits, the mechanism underlying the GABA-T-mediated conversion of GABA has not been fully understood. In this work, we conducted loss-of-function analyses utilizing RNA interference (RNAi) transgenic plants with suppressed pyruvate- and glyoxylate-dependent GABA-T gene expression to clarify which GABA-T isoforms are essential for its function. The RNAi plants with suppressed SlGABA-T gene expression, particularly SlGABA-T1, showed severe dwarfism and infertility. SlGABA-T1 expression was inversely associated with GABA levels in the fruit at the red ripe stage. The GABA contents in 35S::SlGABA-T1(RNAi) lines were 1.3-2.0 times and 6.8-9.2 times higher in mature green and red ripe fruits, respectively, than the contents in wild-type fruits. In addition, SlGABA-T1 expression was strongly suppressed in the GABA-accumulating lines. These results indicate that pyruvate- and glyoxylate-dependent GABA-T is the essential isoform for GABA metabolism in tomato plants and that GABA-T1 primarily contributes to GABA reduction in the ripening fruits.

  6. GABA systems, benzodiazepines, and substance dependence. (United States)

    Malcolm, Robert J


    Alterations in the gamma-aminobutyric acid (GABA) receptor complex and GABA neurotransmission influence the reinforcing and intoxicating effects of alcohol and benzodiazepines. Chronic modulation of the GABA(A)-benzodiazepine receptor complex plays a major role in central nervous system dysregulation during alcohol abstinence. Withdrawal symptoms stem in part from a decreased GABAergic inhibitory function and an increase in glutamatergic excitatory function. GABA(A) receptors play a role in both reward and withdrawal phenomena from alcohol and sedative-hypnotics. Although less well understood, GABA(B) receptor complexes appear to play a role in inhibition of motivation and diminish relapse potential to reinforcing drugs. Evidence suggests that long-term alcohol use and concomitant serial withdrawals permanently alter GABAergic function, down-regulate benzodiazepine binding sites, and in preclinical models lead to cell death. Benzodiazepines have substantial drawbacks in the treatment of substance use-related disorders that include interactions with alcohol, rebound effects, alcohol priming, and the risk of supplanting alcohol dependency with addiction to both alcohol and benzodiazepines. Polysubstance-dependent individuals frequently self-medicate with benzodiazepines. Selective GABA agents with novel mechanisms of action have anxiolytic, anticonvulsant, and reward inhibition profiles that have potential in treating substance use and withdrawal and enhancing relapse prevention with less liability than benzodiazepines. The GABA(B) receptor agonist baclofen has promise in relapse prevention in a number of substance dependence disorders. The GABA(A) and GABA(B) pump reuptake inhibitor tiagabine has potential for managing alcohol and sedative-hypnotic withdrawal and also possibly a role in relapse prevention.

  7. Ambient CO2, fish behaviour and altered GABAergic neurotransmission: exploring the mechanism of CO2-altered behaviour by taking a hypercapnia dweller down to low CO2 levels. (United States)

    Regan, Matthew D; Turko, Andy J; Heras, Joseph; Andersen, Mads Kuhlmann; Lefevre, Sjannie; Wang, Tobias; Bayley, Mark; Brauner, Colin J; Huong, Do Thi Thanh; Phuong, Nguyen Thanh; Nilsson, Göran E


    Recent studies suggest that projected rises of aquatic CO2 levels cause acid-base regulatory responses in fishes that lead to altered GABAergic neurotransmission and disrupted behaviour, threatening fitness and population survival. It is thought that changes in Cl(-) and HCO3 (-) gradients across neural membranes interfere with the function of GABA-gated anion channels (GABAA receptors). So far, such alterations have been revealed experimentally by exposing species living in low-CO2 environments, like many oceanic habitats, to high levels of CO2 (hypercapnia). To examine the generality of this phenomenon, we set out to study the opposite situation, hypothesizing that fishes living in typically hypercapnic environments also display behavioural alterations if exposed to low CO2 levels. This would indicate that ion regulation in the fish brain is fine-tuned to the prevailing CO2 conditions. We quantified pH regulatory variables and behavioural responses of Pangasianodon hypophthalmus, a fish native to the hypercapnic Mekong River, acclimated to high-CO2 (3.1 kPa) or low-CO2 (0.04 kPa) water. We found that brain and blood pH was actively regulated and that the low-CO2 fish displayed significantly higher activity levels, which were reduced after treatment with gabazine, a GABAA receptor blocker. This indicates an involvement of the GABAA receptor and altered Cl(-) and HCO3 (-) ion gradients. Indeed, Goldman calculations suggest that low levels of environmental CO2 may cause significant changes in neural ion gradients in P. hypophthalmus. Taken together, the results suggest that brain ion regulation in fishes is fine-tuned to the prevailing ambient CO2 conditions and is prone to disruption if these conditions change.

  8. GABA receptor imaging

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    Lee, Jong Doo [Yonsei University College of Medicine, Seoul (Korea, Republic of)


    GABA is primary an inhibitory neurotransmitter that is localized in inhibitory interneurons. GABA is released from presynaptic terminals and functions by binding to GABA receptors. There are two types of GABA receptors, GABA{sub A}-receptor that allows chloride to pass through a ligand gated ion channel and GABA{sub B}-receptor that uses G-proteins for signaling. The GABA{sub A}-receptor has a GABA binding site as well as a benzodiazepine binding sites, which modulate GABA{sub A}-receptor function. Benzodiazepine GABAA receptor imaging can be accomplished by radiolabeling derivates that activates benzodiazepine binding sites. There has been much research on flumazenil (FMZ) labeled with {sup 11}C-FMZ, a benzodiazepine derivate that is a selective, reversible antagonist to GABAA receptors. Recently, {sup 18}F-fluoroflumazenil (FFMZ) has been developed to overcome {sup 11}C's short half-life. {sup 18}F-FFMZ shows high selective affinity and good pharmacodynamics, and is a promising PET agent with better central benzodiazepine receptor imaging capabilities. In an epileptic focus, because the GABA/benzodiazepine receptor amount is decreased, using '1{sup 1}C-FMZ PET instead of {sup 18}F-FDG, PET, restrict the foci better and may also help find lesions better than high resolution MR. GABA{sub A} receptors are widely distributed in the cerebral cortex, and can be used as an viable neuronal marker. Therefore it can be used as a neuronal cell viability marker in cerebral ischemia. Also, GABA-receptors decrease in areas where neuronal plasticity develops, therefore, GABA imaging can be used to evaluate plasticity. Besides these usages, GABA receptors are related with psychological diseases, especially depression and schizophrenia as well as cerebral palsy, a motor-related disorder, so further in-depth studies are needed for these areas.

  9. The expression of GABA(B1) and GABA(B2) receptor subunits in the cNS differs from that in peripheral tissues. (United States)

    Calver, A R; Medhurst, A D; Robbins, M J; Charles, K J; Evans, M L; Harrison, D C; Stammers, M; Hughes, S A; Hervieu, G; Couve, A; Moss, S J; Middlemiss, D N; Pangalos, M N


    GABA(B) receptors are G-protein-coupled receptors that mediate the slow and prolonged synaptic actions of GABA in the CNS via the modulation of ion channels. Unusually, GABA(B) receptors form functional heterodimers composed of GABA(B1) and GABA(B2) subunits. The GABA(B1) subunit is essential for ligand binding, whereas the GABA(B2) subunit is essential for functional expression of the receptor dimer at the cell surface. We have used real-time reverse transcriptase-polymerase chain reaction to analyse expression levels of these subunits, and their associated splice variants, in the CNS and peripheral tissues of human and rat. GABA(B1) subunit splice variants were expressed throughout the CNS and peripheral tissues, whereas surprisingly GABA(B2) subunit splice variants were neural specific. Using novel antisera specific to individual GABA(B) receptor subunits, we have confirmed these findings at the protein level. Analysis by immunoblotting demonstrated the presence of the GABA(B1) subunit, but not the GABA(B2) subunit, in uterus and spleen. Furthermore, we have shown the first immunocytochemical analysis of the GABA(B2) subunit in the brain and spinal cord using a GABA(B2)-specific antibody. We have, therefore, identified areas of non-overlap between GABA(B1) and GABA(B2) subunit expression in tissues known to contain functional GABA(B) receptors. Such areas are of interest as they may well contain novel GABA(B) receptor subunit isoforms, expression of which would enable the GABA(B1) subunit to reach the cell surface and form functional GABA(B) receptors.

  10. How and why does tomato accumulate a large amount of GABA in the fruit?

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    Mariko eTakayama


    Full Text Available γ-Aminobutyric acid (GABA has received much attention as a health-promoting functional compound, and several GABA-enriched foods have been commercialized. In higher plants, GABA is primarily metabolized via a short pathway called the GABA shunt. The GABA shunt bypasses two steps (the oxidation of α-ketoglutarate to succinate of the tricarboxylic acid (TCA cycle via reactions catalysed by three enzymes: glutamate decarboxylase (GAD, GABA transaminase (GABA-T and succinic semialdehyde dehydrogenase (SSADH. The GABA shunt plays a major role in primary carbon and nitrogen metabolism and is an integral part of the TCA cycle under stress and non-stress conditions. Tomato is one of the major crops that accumulate a relatively high level of GABA in its fruits. The GABA levels in tomato fruits dramatically change during fruit development; the GABA levels increase from flowering to the mature green stage and then rapidly decrease during the ripening stage. Although GABA constitutes up to 50% of the free amino acids at the mature green stage, the molecular mechanism of GABA accumulation and the physiological function of GABA during tomato fruit development remain unclear. In this review, we summarize recent studies of GABA accumulation in tomato fruits and discuss the potential biological roles of GABA in tomato fruit development.

  11. Creatine uptake in mouse hearts with genetically altered creatine levels



    Creatine plays an important role in energy metabolism in the heart. Cardiomyocytes accumulate creatine via a specific creatine transporter (CrT), the capacity of which is reduced in the failing heart, resulting in lower myocardial creatine concentration. Therefore, to gain insight into how the CrT is regulated, we studied two mouse models of severely altered myocardial creatine levels. Cardiac creatine uptake levels were measured in isolated hearts from creatine-free guanidinoacetate-N-methyl...

  12. Tributyltin exposure alters cytokine levels in mouse serum. (United States)

    Lawrence, Shanieek; Pellom, Samuel T; Shanker, Anil; Whalen, Margaret M


    Tributyltin (TBT), a toxic environmental contaminant, has been widely utilized for various industrial, agricultural and household purposes. Its usage has led to a global contamination and its bioaccumulation in aquatic organisms and terrestrial mammals. Previous studies suggest that TBT has debilitating effects on the overall immune function of animals, rendering them more vulnerable to diseases. TBT (at concentrations that have been detected in human blood) alters secretion of inflammatory cytokines from human lymphocytes ex vivo. Thus, it is important to determine if specified levels of TBT can alter levels of cytokines in an in vivo system. Mice were exposed to biologically relevant concentrations of TBT (200, 100 or 25 nM final concentrations). The quantitative determination of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL2, IL5, IL7, IL12βp40, IL13, IL15, keratinocyte chemoattractant (KC), macrophage inflammatory protein 1β (MIP), MIP2 and regulated on activation normal T-cell-expressed and secreted (RANTES) was performed in mouse sera by MAGPIX analysis and Western blot. Results indicated alterations (both decreases and increases) in several cytokines. The pro-inflammatory cytokines IFNγ, TNFα, IL-1β, IL-2, IL5, IL12βp40 and IL-15 were altered as were the chemokines MIP-1 and RANTES and the anti-inflammatory cytokine IL-13. Increases in IFNγ and TNFα were seen in the serum of mice exposed to TBT for less than 24 h. Levels of IL1β, IL-12 βp40, IL-5 and IL-15 were also modulated in mouse serum, depending on the specific experiment and exposure level. IL-2 was consistently decreased in mouse serum when animals were exposed to TBT. There were also TBT-induced increases in MIP-1β, RANTES and IL-13. These results from human and murine samples clearly suggest that TBT exposures modulate the secretion inflammatory cytokines.

  13. The effect of morphine sensitization on extracellular concentrations of GABA in dorsal hippocampus of male rats. (United States)

    Farahmandfar, Maryam; Zarrindast, Mohammad-Reza; Kadivar, Mehdi; Karimian, Seyed Morteza; Naghdi, Nasser


    Repeated, intermittent exposure to drugs of abuse, such as morphine results in response enhancements to subsequent drug treatments, a phenomenon referred to as behavioral sensitization. As persistent neuronal sensitization may contribute to the long-lasting consequences of drug abuse, characterizing the neurochemical mechanisms of sensitization is providing insights into addiction. Although it has been shown that GABAergic systems in the CA1 region of dorsal hippocampus are involved in morphine sensitization, the alteration of extracellular level of GABA in this area in morphine sensitization has not been investigated. In the present study, using the in vivo microdialysis technique, we investigated the effect of morphine sensitization on extracellular GABA concentration in CA1 region of dorsal hippocampus of freely moving rats. Sensitization was induced by subcutaneous (s.c.) injection of morphine, once daily for 3 days followed by 5 days free of the opioid treatment. The results showed that extracellular GABA concentration in CA1 was decreased following acute administration of morphine in non-sensitized rats. However, morphine-induced behavioral sensitization significantly increased the extracellular GABA concentration in this area. The enhancement of GABA in morphine sensitized rats was inhibited by administration of naloxone 30 min before each of three daily doses of morphine. These results suggest an adaptation of the GABAergic neuronal transmission in dorsal hippocampus induced by morphine sensitization and it is implied that opioid receptors may play an important role in this effect.

  14. Systematic analysis of γ-aminobutyric acid (GABA) metabolism and function in the social amoeba Dictyostelium discoideum. (United States)

    Wu, Yuantai; Janetopoulos, Chris


    While GABA has been suggested to regulate spore encapsulation in the social amoeba Dictyostelium discoideum, the metabolic profile and other potential functions of GABA during development remain unclear. In this study, we investigated the homeostasis of GABA metabolism by disrupting genes related to GABA metabolism and signaling. Extracellular levels of GABA are tightly regulated during early development, and GABA is generated by the glutamate decarboxylase, GadB, during growth and in early development. However, overexpression of the prespore-specific homologue, GadA, in the presence of GadB reduces production of extracellular GABA. Perturbation of extracellular GABA levels delays the process of aggregation. Cytosolic GABA is degraded by the GABA transaminase, GabT, in the mitochondria. Disruption of a putative vesicular GABA transporter (vGAT) homologue DdvGAT reduces secreted GABA. We identified the GABAB receptor-like family member GrlB as the major GABA receptor during early development, and either disruption or overexpression of GrlB delays aggregation. This delay is likely the result of an abolished pre-starvation response and late expression of several "early" developmental genes. Distinct genes are employed for GABA generation during sporulation. During sporulation, GadA alone is required for generating GABA and DdvGAT is likely responsible for GABA secretion. GrlE but not GrlB is the GABA receptor during late development.

  15. [Autoantibodies to glutamate and GABA in opiate addiction]. (United States)

    Vetrile, L A; Fomina, V G; Nevidimova, T I; Vetlugina, T P; Batukhtina, E I; Savochkina, D N; Zakharova, I A; Davydova, T V


    Blood serum from 129 patients with opium addiction at different stages of the disease and 63 donors (control group) was examined for the presence of autoantibodies to the exciting and inhibitory amino acids glutamate and GABA. It was shown enhanced production of autoantibodies to glutamate and GABA. Dependence of the level and frequency of detec- tion of autoantibodies to glutamate and GABA on the stage of the disease was revealed.


    Directory of Open Access Journals (Sweden)



    Full Text Available Deoxynivalenol (DON is a mycotoxin produced by different species of Fusarium genus that may contaminate feed and food. In the present study we investigated the effect of low levels of DON on the modulation of performance, hemodynamic parameters, cellular and humoral immune response in weaned pigs. Histological alterations in different organ tissues were also analyzed. Our results showed that a short in vivo exposure (14 days of weanling piglets to 0; 0.5; 1.5 mg/day of DON significantly induced a dose dependent increase of cellular immune response (lymphocytes proliferation and leucocytes numbers. The 0.5 and 1.5 mg/day of DON modulated also the humoral immune response by increasing the immunoglobulin A synthesis with 7.32 % and 37.98 % and by decreasing that of immunoglubulin G with 11.15 % and 36.87 %, respectively when compared with the control. DON produced also alterations in the hemodynamic parameters of intoxicated piglets; the activity of lactate dehydrogenase significantly increased while the activity of L-glutamate, alkaline phosphatase, urea and creatinine significantly decreased. Both doses of the toxin induced microscopic alterations of the internal organ structure. By contrast, ingestion of the contaminated material had no effect on the performance (weight gain, feed consumption, and feed efficiency, organ weights, and total serum concentration of cholesterol, calcium, sodium and potassium. Taken together these results suggest that even when present at low level DON can affect blood parameters, humoral and cellular immune response in weaned piglets with a significant importance for the swine health.

  17. Trophic actions of GABA on neuronal development. (United States)

    Represa, Alfonso; Ben-Ari, Yehezkel


    During brain development, transmitter-gated receptors are operative before synapse formation, suggesting that their action is not restricted to synaptic transmission. GABA, which is the principal excitatory transmitter in the developing brain, acts as an epigenetic factor to control processes including cell proliferation, neuroblast migration and dendritic maturation. These effects appear to be mediated through a paracrine, diffuse, non-synaptic mode of action that precedes the more focused, rapid mode of operation characteristic of synaptic connections. This sequential operation implies that GABA is used as an informative agent but in a unique context at an early developmental stage. This sequence also implies that by altering these effects, drugs acting on the GABA system could be pathogenic during pregnancy.

  18. Anion transport and GABA signaling

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    Christian Andreas Huebner


    Full Text Available Whereas activation of GABAA receptors by GABA usually results in a hyperpolarizing influx of chloride into the neuron, the reversed chloride driving force in the immature nervous system results in a depolarizing efflux of chloride. This GABAergic depolarization is deemed to be important for the maturation of the neuronal network. The concept of a developmental GABA switch has mainly been derived from in vitro experiments and reliable in vivo evidence is still missing. As GABAA receptors are permeable for both chloride and bicarbonate, the net effect of GABA also critically depends on the distribution of bicarbonate. Whereas chloride can either mediate depolarizing or hyperpolarizing currents, bicarbonate invariably mediates a depolarizing current under physiological conditions. Intracellular bicarbonate is quickly replenished by cytosolic carbonic anhydrases. Intracellular bicarbonate levels also depend on different bicarbonate transporters expressed by neurons. The expression of these proteins is not only developmentally regulated but also differs between cell types and even subcellular regions. In this review we will summarize current knowledge about the role of some of these transporters for brain development and brain function.

  19. Marlin-1, a novel RNA-binding protein associates with GABA receptors. (United States)

    Couve, Andrés; Restituito, Sophie; Brandon, Julia M; Charles, Kelly J; Bawagan, Hinayana; Freeman, Katie B; Pangalos, Menelas N; Calver, Andrew R; Moss, Stephen J


    GABA(B) receptors are heterodimeric G protein-coupled receptors that mediate slow synaptic inhibition in the central nervous system. Whereas heterodimerization between GABA(B) receptor GABA(B)R1 and GABA(B)R2 subunits is essential for functional expression, how neurons coordinate the assembly of these critical receptors remains to be established. Here we have identified Marlin-1, a novel GABA(B) receptor-binding protein that associates specifically with the GABA(B)R1 subunit in yeast, tissue culture cells, and neurons. Marlin-1 is expressed in the brain and exhibits a granular distribution in cultured hippocampal neurons. Marlin-1 binds different RNA species including the 3'-untranslated regions of both the GABA(B)R1 and GABA(B)R2 mRNAs in vitro and also associates with RNA in cultured neurons. Inhibition of Marlin-1 expression via small RNA interference technology results in enhanced intracellular levels of the GABA(B)R2 receptor subunit without affecting the level of GABA(B)R1. Together our results suggest that Marlin-1 functions to regulate the cellular levels of GABA(B) R2 subunits, which may have significant effects on the production of functional GABA(B) receptor heterodimers. Therefore, our observations provide an added level of regulation for the control of GABA(B) receptor expression and for the efficacy of inhibitory synaptic transmission.

  20. Anthropogenic noise alters bat activity levels and echolocation calls

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    Jessie P. Bunkley


    Full Text Available Negative impacts from anthropogenic noise are well documented for many wildlife taxa. Investigations of the effects of noise on bats however, have not been conducted outside of the laboratory. Bats that hunt arthropods rely on auditory information to forage. Part of this acoustic information can fall within the spectrum of anthropogenic noise, which can potentially interfere with signal reception and processing. Compressor stations associated with natural gas extraction produce broadband noise 24 hours a day, 365 days a year. With over half a million producing gas wells in the U.S. this infrastructure is a major source of noise pollution across the landscape. We conducted a ‘natural experiment’ in the second largest gas extraction field in the U.S. to investigate the potential effects of gas compressor station noise on the activity levels of the local bat assemblage. We used acoustic monitoring to compare the activity level (number of minutes in a night with a bat call of the bat assemblage at sites with compressor stations to sites lacking this infrastructure. We found that activity levels for the Brazilian free-tailed bat (Tadarida brasiliensis were 40% lower at loud compressor sites compared to quieter well pads, whereas the activity levels of four other species (Myotis californicus, M. cillolabrum, M. lucifugus, Parastrellus hesperus were not affected by noise. Furthermore, our results reveal that the assemblage of bat species emitting low frequency (35 kHz echolocation did not exhibit altered activity levels in noise. Lower activity levels of Brazilian free-tailed bats at loud sites indicate a potential reduction in habitat for this species. Additionally, a comparison of echolocation search calls produced by free-tailed bats at sites with and without compressor stations reveal that this species modifies its echolocation search calls in noise—producing longer calls with a narrower bandwidth. Call alterations might affect prey

  1. Effects of the 5-HT1B receptor antagonist NAS-181 on extracellular levels of acetylcholine, glutamate and GABA in the frontal cortex and ventral hippocampus of awake rats: a microdialysis study. (United States)

    Hu, Xiao Jing; Wang, Fu-Hua; Stenfors, Carina; Ogren, Sven Ove; Kehr, Jan


    The purpose of this study was to investigate the effects of the 5-HT(1B) receptor antagonist NAS-181 ((R)-(+)-2-(3-morpholinomethyl-2H-chromen-8-yl) oxymethyl-morpholine methanesulfonate) on cholinergic, glutamatergic and GABA-ergic neurotransmission in the rat brain in vivo. Extracellular levels of acetylcholine, glutamate and GABA were monitored by microdialysis in the frontal cortex (FC) and ventral hippocampus (VHipp) in separate groups of freely moving rats. NAS-181 (1, 5 or 10 mg/kg, s.c.) caused a dose-dependent increase in ACh levels, reaching the maximal values of 500% (FC) and 230% (VHipp) of controls at 80 min post-injection. On the contrary, NAS-181 injected at doses of 10 or 20 mg/kg s.c. had no effect on basal extracellular levels of Glu and GABA in these areas. The present data suggest that ACh neurotransmission in the FC and VHipp, the brain structures strongly implicated in cognitive function, is under tonic inhibitory control of 5-HT(1B) heteroreceptors localized at the cholinergic terminals in these areas.

  2. 3D GABA imaging with real-time motion correction, shim update and reacquisition of adiabatic spiral MRSI. (United States)

    Bogner, Wolfgang; Gagoski, Borjan; Hess, Aaron T; Bhat, Himanshu; Tisdall, M Dylan; van der Kouwe, Andre J W; Strasser, Bernhard; Marjańska, Małgorzata; Trattnig, Siegfried; Grant, Ellen; Rosen, Bruce; Andronesi, Ovidiu C


    Gamma-aminobutyric acid (GABA) and glutamate (Glu) are the major neurotransmitters in the brain. They are crucial for the functioning of healthy brain and their alteration is a major mechanism in the pathophysiology of many neuro-psychiatric disorders. Magnetic resonance spectroscopy (MRS) is the only way to measure GABA and Glu non-invasively in vivo. GABA detection is particularly challenging and requires special MRS techniques. The most popular is MEscher-GArwood (MEGA) difference editing with single-voxel Point RESolved Spectroscopy (PRESS) localization. This technique has three major limitations: a) MEGA editing is a subtraction technique, hence is very sensitive to scanner instabilities and motion artifacts. b) PRESS is prone to localization errors at high fields (≥3T) that compromise accurate quantification. c) Single-voxel spectroscopy can (similar to a biopsy) only probe steady GABA and Glu levels in a single location at a time. To mitigate these problems, we implemented a 3D MEGA-editing MRS imaging sequence with the following three features: a) Real-time motion correction, dynamic shim updates, and selective reacquisition to eliminate subtraction artifacts due to scanner instabilities and subject motion. b) Localization by Adiabatic SElective Refocusing (LASER) to improve the localization accuracy and signal-to-noise ratio. c) K-space encoding via a weighted stack of spirals provides 3D metabolic mapping with flexible scan times. Simulations, phantom and in vivo experiments prove that our MEGA-LASER sequence enables 3D mapping of GABA+ and Glx (Glutamate+Gluatmine), by providing 1.66 times larger signal for the 3.02ppm multiplet of GABA+ compared to MEGA-PRESS, leading to clinically feasible scan times for 3D brain imaging. Hence, our sequence allows accurate and robust 3D-mapping of brain GABA+ and Glx levels to be performed at clinical 3T MR scanners for use in neuroscience and clinical applications.

  3. The Timing of the Excitatory-to-Inhibitory GABA Switch Is Regulated by the Oxytocin Receptor via KCC2

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    Marianna Leonzino


    Full Text Available Oxytocin and its receptor (Oxtr play a crucial role in the postnatal transition of neuronal GABA neurotransmission from excitatory to inhibitory, a developmental process known as the GABA switch. Using hippocampal neurons from Oxtr-null mice, we show that (1 Oxtr is necessary for the correct timing of the GABA switch by upregulating activity of the chloride cotransporter KCC2, (2 Oxtr, in a very early and narrow time window, directly modulates the functional activity of KCC2 by promoting its phosphorylation and insertion/stabilization at the neuronal surface, and (3 in the absence of Oxtr, electrophysiological alterations are recorded in mature neurons, a finding consistent with a reduced level of KCC2 and increased susceptibility to seizures observed in adult Oxtr-null mice. These data identify KCC2 as a key target of oxytocin in postnatal events that may be linked to pathogenesis of neurodevelopmental disorders.

  4. Brain microdialysis of GABA and glutamate : What does it signify?

    NARCIS (Netherlands)

    Timmerman, W; Westerink, BHC


    Microdialysis has become a frequently used method to study extracellular levels of GABA and glutamate in the central nervous system. However, the fact that the major part of GABA and glutamate as measured by microdialysis does not fulfill the classical criteria for exocytotic release questions the v

  5. Characteristics of gamma-aminobutyric acid (GABA receptors in the rat central nervous system.

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    Full Text Available Characteristics of gamma-aminobutyric acid (GABA were investigated in the rat central nervous system by radioreceptor assay (RRA. Scatchard analysis revealed that the rat brain had two distinct GABA binding sites with an apparent dissociation constant (Kd of 11.7 nM and 34.7 nM. The highest level of specific [3H]-GABA binding was found in the rat cerebellum. Imidazole acetic acid, a potent GABA agonist, was effective in displacing [3H]-GABA binding but beta-alanine was slightly effective in inhibiting [3H]-GABA binding. Muscimol, the most potent GABA agonist, has been used as a ligand to characterize the postsynaptic GABA receptors. However, the maximal binding capacity (Bmax of muscimol-RRA was about 3 times larger than that of GABA-RRA, suggesting that muscimol might label not only GABA receptors but other unknown receptors as well. An endogenous inhibitor of GABA receptor binding was purified from the P2 fraction of rat brain with 0.05% Triton X-100. The endogenous inhibitor was competitive with GABA on GABA binding sites. The inhibition by the endogenous inhibitor of GABA receptor binding was blocked by the allosteric effect of diazepam. In the presence of diazepam, [3H]-GABA binding with the endogenous inhibitor was larger than that with GABA, whereas there was no difference in the absence of diazepam. This indicated that the endogenous inhibitor was not GABA itself. The molecular weight of the endogenous inhibitor was estimate by gel filtration to be less than 3,000 daltons.

  6. GABA, Selank, and Olanzapine Affect the Expression of Genes Involved in GABAergic Neurotransmission in IMR-32 Cells (United States)

    Filatova, Elena; Kasian, Anastasiya; Kolomin, Timur; Rybalkina, Ekaterina; Alieva, Anelya; Andreeva, Lyudmila; Limborska, Svetlana; Myasoedov, Nikolay; Pavlova, Galina; Slominsky, Petr; Shadrina, Maria


    Clinical studies have shown that Selank had an anxiolytic effect comparable to that of classical benzodiazepine drugs, which can enhance the inhibitory effect of GABA by allosteric modulation of GABAA receptors. These data suggest that the molecular mechanism of the effect of Selank may also be related to its ability to affect the performance of the GABAergic system. To test this hypothesis, we studied the changes in expression of 84 genes involved in the functioning of the GABAergic system and in the processes of neurotransmission in the culture of neuroblastoma IMR-32 cells using qPCR method. As test substances, in addition to Selank, we selected the major GABAA receptor ligand, GABA, the atypical antipsychotic, olanzapine, and combinations of these compounds (Selank and GABA; Selank and olanzapine). We found no changes in the mRNA levels of the genes studied under the effect of Selank. The combined effect of GABA and Selank led to nearly complete suppression of changes in expression of genes in which mRNA levels changed under the effect of GABA. When Selank was used in conjunction with olanzapine, the expression alterations of more genes were observed compared with olanzapine alone. The data obtained indicate that Selank has no direct effect on the mRNA levels of the GABAergic system genes in neuroblastoma IMR-32 cells. At the same time, our results partially confirm the hypothesis that the peptide may affect the interaction of GABA with GABAA receptors. Our data also suggest that Selank may enhance the effect of olanzapine on the expression of the genes studied. PMID:28293190

  7. Attenuation of γ-aminobutyric acid (GABA) transaminase activity contributes to GABA increase in the cerebral cortex of mice exposed to β-cypermethrin. (United States)

    Han, Y; Cao, D; Li, X; Zhang, R; Yu, F; Ren, Y; An, L


    The current study investigated the γ-aminobutyric acid (GABA) levels and GABA metabolic enzymes (GABA transaminase (GABA(T)) and glutamate decarboxylase (GAD)) activities at 2 and 4 h after treatment, using a high-performance liquid chromatography with ultraviolet detectors and colorimetric assay, in the cerebral cortex of mice treated with 20, 40 or 80 mg/kg β-cypermethrin by a single oral gavage, with corn oil as vehicle control. In addition, GABA protein (4 h after treatment), GABA(T) protein (2 h after treatment) and GABA receptors messenger RNA (mRNA) expression were detected by immunohistochemistry, Western blot and real-time quantitative reverse transcriptase polymerase chain reaction, respectively. β-Cypermethrin (80 mg/kg) significantly increased GABA levels in the cerebral cortex of mice, at both 2 and 4 h after treatment, compared with the control. Also, GABA immunohistochemistry results suggested that the number of positive granules was increased in the cerebral cortex of mice 4 h after exposure to 80 mg/kg β-cypermethrin when compared with the control. Furthermore, the results also showed that GABA(T) activity detected was significantly decreased in the cerebral cortex of mice 2 h after β-cypermethrin administration (40 or 80 mg/kg). No significant changes were found in GAD activity, or the expression of GABA(T) protein and GABAB receptors mRNA, in the cerebral cortex of mice, except that 80 mg/kg β-cypermethrin caused a significant decrease, compared with the vehicle control, in GABAA receptors mRNA expression 4 h after administration. These results suggested that attenuated GABA(T) activity induced by β-cypermethrin contributed to increased GABA levels in the mouse brain. The downregulated GABAA receptors mRNA expression is most likely a downstream event.

  8. GABA-BZD Receptor Modulating Mechanism of Panax quinquefolius against 72-hours Sleep Deprivation Induced Anxiety like Behavior: Possible Roles of Oxidative Stress, Mitochondrial Dysfunction and Neuroinflammation

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    Priyanka eChanana


    Full Text Available ABSTRACTRationale- Panax quinquefolius (American Ginseng is known for its therapeutic potential against various neurological disorders, but its plausible mechanism of action still remains undeciphered. GABA (Gamma Amino Butyric Acid plays an important role in sleep wake cycle homeostasis. Thus there exists rationale in exploring the GABA-ergic potential of Panax quinquefolius as neuroprotective strategy in sleep deprivation induced secondary neurological problems.Objective- The present study was designed to explore the possible GABA-ergic mechanism in the neuro-protective effect of Panax quinquefolius against 72-hours sleep deprivation induced anxiety like behaviour, oxidative stress, mitochondrial dysfunction, HPA-axis activation and neuroinflammation.Materials and Methods- Male laca mice were sleep deprived for 72-hours by using Grid suspended over water method. Panax quinquefolius (American Ginseng 50, 100 and 200 mg/kg was administered alone and in combination with GABA modulators (GABA Cl- channel inhibitor, GABA-benzodiazepine receptor inhibitor and GABAA agonist for 8 days, starting five days prior to 72-hours sleep deprivation period. Various behavioural (locomotor activity, mirror chamber test, biochemical (lipid peroxidation, reduced glutathione, catalase, nitrite levels, mitochondrial complexes, neuroinflammation marker (Tumour Necrosis Factor, TNF-alpha, serum corticosterone, and histopathological sections of brains were assessed. Results- 72-hours sleep deprivation significantly impaired locomotor activity, caused anxiety-like behaviour, conditions of oxidative stress, alterations in mitochondrial enzyme complex activities, raised serum corticosterone levels, brain TNFα levels and led to neuroinflammation like signs in discrete brain areas as compared to naive group. Panax quinquefolius (100 and 200 mg/kg treatment restored the behavioural, biochemical, mitochondrial, molecular and histopathological alterations. Pre-treatment of

  9. Alterations in nigral NMDA and GABAA receptor control of the striatal dopamine level after repetitive exposures to nitrogen narcosis. (United States)

    Lavoute, Cécile; Weiss, Michel; Rostain, Jean-Claude


    Nitrogen pressure exposure in rats results in decreased dopamine (DA) release at the striatal terminals of the substantia nigra pars compacta (SNc) dopaminergic neurons, demonstrating the narcotic potency of nitrogen. This effect is attributed to decreased excitatory and increased inhibitory inputs to dopaminergic neurons, involving a change in NMDA and GABA(A) receptor function. We investigated whether repetitive exposures to nitrogen modify the excitatory and inhibitory control of the dopaminergic nigro-striatal pathway. We used voltammetry to measure dopamine levels in freely-moving rats, implanted with dopamine-sensitive electrodes in the striatum. NMDA/GABA(A) receptor agonists (NMDA/muscimol) and antagonists (AP7/gabazine) were administered through a guide-cannula into the SNc, and their effects on striatal dopamine levels were measured under normobaric conditions, before and after five repetitive exposures to 1 MPa nitrogen. NMDA-mediated dopamine release was greater following repetitive exposures, AP7-mediated inhibition of glutamatergic input was blocked, suggesting that NMDA receptor sensitivity was increased and glutamate release reduced. Muscimol did not modify dopamine levels following repetitive exposures, whereas the effect of gabazine was greater after exposures than before. This suggested that interneuronal GABA(A) receptors were desensitized, leading to an increased GABAergic input at dopaminergic cells. Thus, repetitive nitrogen exposure induced persistent changes in glutamatergic and GABAergic control of dopaminergic neurons, resulting in decreased activity of the nigrostriatal pathway.

  10. Salt stress alters DNA methylation levels in alfalfa (Medicago spp). (United States)

    Al-Lawati, A; Al-Bahry, S; Victor, R; Al-Lawati, A H; Yaish, M W


    Modification of DNA methylation status is one of the mechanisms used by plants to adjust gene expression at both the transcriptional and posttranscriptional levels when plants are exposed to suboptimal conditions. Under abiotic stress, different cultivars often show heritable phenotypic variation accompanied by epigenetic polymorphisms at the DNA methylation level. This variation may provide the raw materials for plant breeding programs that aim to enhance abiotic stress tolerance, including salt tolerance. In this study, methylation-sensitive amplified polymorphism (MSAP) analysis was used to assess cytosine methylation levels in alfalfa (Medicago spp) roots exposed to increasing NaCl concentrations (0.0, 8.0, 12.0, and 20.0 dS/m). Eleven indigenous landraces were analyzed, in addition to a salt-tolerant cultivar that was used as a control. There was a slight increase in DNA methylation upon exposure to high levels of soil salinity. Phylogenetic analysis using MSAP showed epigenetic variation within and between the alfalfa landraces when exposed to saline conditions. Based on MSAP and enzyme-linked immunosorbent assay results, we found that salinity increased global DNA methylation status, particularly in plants exposed to the highest level of salinity (20 dS/m). Quantitative reverse transcription-polymerase chain reaction indicated that this might be mediated by the overexpression of methyltransferase homolog genes after exposure to saline conditions. DNA demethylation using 5-azacytidine reduced seedling lengths and dry and fresh weights, indicating a possible decrease in salinity tolerance. These results suggest that salinity affects DNA methylation flexibility.

  11. GABA Metabolism and Transport: Effects on Synaptic Efficacy

    Directory of Open Access Journals (Sweden)

    Fabian C. Roth


    Full Text Available GABAergic inhibition is an important regulator of excitability in neuronal networks. In addition, inhibitory synaptic signals contribute crucially to the organization of spatiotemporal patterns of network activity, especially during coherent oscillations. In order to maintain stable network states, the release of GABA by interneurons must be plastic in timing and amount. This homeostatic regulation is achieved by several pre- and postsynaptic mechanisms and is triggered by various activity-dependent local signals such as excitatory input or ambient levels of neurotransmitters. Here, we review findings on the availability of GABA for release at presynaptic terminals of interneurons. Presynaptic GABA content seems to be an important determinant of inhibitory efficacy and can be differentially regulated by changing synthesis, transport, and degradation of GABA or related molecules. We will discuss the functional impact of such regulations on neuronal network patterns and, finally, point towards pharmacological approaches targeting these processes.

  12. Glutamate and GABA-metabolizing enzymes in post-mortem cerebellum in Alzheimer's disease: phosphate-activated glutaminase and glutamic acid decarboxylase. (United States)

    Burbaeva, G Sh; Boksha, I S; Tereshkina, E B; Savushkina, O K; Prokhorova, T A; Vorobyeva, E A


    Enzymes of glutamate and GABA metabolism in postmortem cerebellum from patients with Alzheimer's disease (AD) have not been comprehensively studied. The present work reports results of original comparative study on levels of phosphate-activated glutaminase (PAG) and glutamic acid decarboxylase isoenzymes (GAD65/67) in autopsied cerebellum samples from AD patients and matched controls (13 cases in each group) as well as summarizes published evidence for altered levels of PAG and GAD65/67 in AD brain. Altered (decreased) levels of these enzymes and changes in links between amounts of these enzymes and other glutamate-metabolizing enzymes (such as glutamate dehydrogenase and glutamine synthetase-like protein) in AD cerebella suggest significantly impaired glutamate and GABA metabolism in this brain region, which was previously regarded as not substantially involved in AD pathogenesis.

  13. The GABA excitatory/inhibitory shift in brain maturation and neurological disorders. (United States)

    Ben-Ari, Yehezkel; Khalilov, Ilgam; Kahle, Kristopher T; Cherubini, Enrico


    Ionic currents and the network-driven patterns they generate differ in immature and adult neurons: The developing brain is not a "small adult brain." One of the most investigated examples is the developmentally regulated shift of actions of the transmitter GABA that inhibit adult neurons but excite immature ones because of an initially higher intracellular chloride concentration [Cl(-)](i), leading to depolarizing and often excitatory actions of GABA instead of hyperpolarizing and inhibitory actions. The levels of [Cl(-)](i) are also highly labile, being readily altered transiently or persistently by enhanced episodes of activity in relation to synaptic plasticity or a variety of pathological conditions, including seizures and brain insults. Among the plethora of channels, transporters, and other devices involved in controlling [Cl(-)](i), two have emerged as playing a particularly important role: the chloride importer NKCC1 and the chloride exporter KCC2. Here, the authors stress the importance of determining how [Cl(-)](i) is dynamically regulated and how this affects brain operation in health and disease. In a clinical perspective, agents that control [Cl(-)](i) and reinstate inhibitory actions of GABA open novel therapeutic perspectives in many neurological disorders, including infantile epilepsies, autism spectrum disorders, and other developmental disorders.

  14. Impairment of GABA transporter GAT-1 terminates cortical recurrent network activity via enhanced phasic inhibition

    Directory of Open Access Journals (Sweden)

    Daniel Simon Razik


    Full Text Available In the central nervous system, GABA transporters (GATs very efficiently clear synaptically released GABA from the extracellular space, and thus exert a tight control on GABAergic inhibition. In neocortex, GABAergic inhibition is heavily recruited during recurrent phases of spontaneous action potential activity which alternate with neuronally quiet periods. Therefore, such activity should be quite sensitive to minute alterations of GAT function. Here, we explored the effects of a gradual impairment of GAT-1 and GAT-2/3 on spontaneous recurrent network activity – termed network bursts and silent periods – in organotypic slice cultures of rat neocortex. The GAT-1 specific antagonist NO-711 depressed activity already at nanomolar concentrations (IC50 for depression of spontaneous multiunit firing rate of 42 nM, reaching a level of 80% at 500-1000 nM. By contrast, the GAT-2/3 preferring antagonist SNAP-5114 had weaker and less consistent effects. Several lines of evidence pointed towards an enhancement of phasic GABAergic inhibition as the dominant activity-depressing mechanism: network bursts were drastically shortened, phasic GABAergic currents decayed slower, and neuronal excitability during ongoing activity was diminished. In silent periods, NO-711 had little effect on neuronal excitability or membrane resistance, quite in contrast to the effects of muscimol, a GABA mimetic which activates GABAA receptors tonically. Our results suggest that an enhancement of phasic GABAergic inhibition efficiently curtails cortical recurrent activity and may mediate antiepileptic effects of therapeutically relevant concentrations of GAT-1 antagonists.

  15. GABA, a natural immunomodulator of T lymphocytes

    DEFF Research Database (Denmark)

    Bjurstöm, Helen; Wang, Junyang; Ericsson, Ida


    gamma-aminobutyric acid (GABA) is the main neuroinhibitory transmitter in the brain. Here we show that GABA in the extracellular space may affect the fate of pathogenic T lymphocytes entering the brain. We examined in encephalitogenic T cells if they expressed functional GABA channels that could......M and higher GABA concentrations decreased T cell proliferation. The results are consistent with GABA being immunomodulatory....

  16. A fluorescence-coupled assay for gamma aminobutyric acid (GABA reveals metabolic stress-induced modulation of GABA content in neuroendocrine cancer.

    Directory of Open Access Journals (Sweden)

    Joseph E Ippolito

    Full Text Available Pathways involved in the synthesis of the neurotransmitter gamma-aminobutyric acid (GABA have been implicated in the pathogenesis of high grade neuroendocrine (NE neoplasms as well as neoplasms from a non-NE lineage. Using The Cancer Genome Atlas, overexpression of the GABA synthetic enzyme, glutamate decarboxylase 1 (GAD1, was found to be associated with decreased disease free-survival in prostate adenocarcinoma and decreased overall survival in clear cell renal cell carcinomas. Furthermore, GAD1 was found to be expressed in castrate-resistant prostate cancer cell lines, but not androgen-responsive cell lines. Using a novel fluorescence-coupled enzymatic microplate assay for GABA mediated through reduction of resazurin in a prostate neuroendocrine carcinoma (PNEC cell line, acid microenvironment-induced stress increased GABA levels while alkaline microenvironment-induced stress decreased GABA through modulation of GAD1 and glutamine synthetase (GLUL activities. Moreover, glutamine but not glucose deprivation decreased GABA through modulation of GLUL. Consistent with evidence in prokaryotic and eukaryotic organisms that GABA synthesis mediated through GAD1 may play a crucial role in surviving stress, GABA may be an important mediator of stress survival in neoplasms. These findings identify GABA synthesis and metabolism as a potentially important pathway for regulating cancer cell stress response as well as a potential target for therapeutic strategies.

  17. A fluorescence-coupled assay for gamma aminobutyric acid (GABA) reveals metabolic stress-induced modulation of GABA content in neuroendocrine cancer. (United States)

    Ippolito, Joseph E; Piwnica-Worms, David


    Pathways involved in the synthesis of the neurotransmitter gamma-aminobutyric acid (GABA) have been implicated in the pathogenesis of high grade neuroendocrine (NE) neoplasms as well as neoplasms from a non-NE lineage. Using The Cancer Genome Atlas, overexpression of the GABA synthetic enzyme, glutamate decarboxylase 1 (GAD1), was found to be associated with decreased disease free-survival in prostate adenocarcinoma and decreased overall survival in clear cell renal cell carcinomas. Furthermore, GAD1 was found to be expressed in castrate-resistant prostate cancer cell lines, but not androgen-responsive cell lines. Using a novel fluorescence-coupled enzymatic microplate assay for GABA mediated through reduction of resazurin in a prostate neuroendocrine carcinoma (PNEC) cell line, acid microenvironment-induced stress increased GABA levels while alkaline microenvironment-induced stress decreased GABA through modulation of GAD1 and glutamine synthetase (GLUL) activities. Moreover, glutamine but not glucose deprivation decreased GABA through modulation of GLUL. Consistent with evidence in prokaryotic and eukaryotic organisms that GABA synthesis mediated through GAD1 may play a crucial role in surviving stress, GABA may be an important mediator of stress survival in neoplasms. These findings identify GABA synthesis and metabolism as a potentially important pathway for regulating cancer cell stress response as well as a potential target for therapeutic strategies.

  18. Synchronization by Food Access Modifies the Daily Variations in Expression and Activity of Liver GABA Transaminase

    Directory of Open Access Journals (Sweden)

    Dalia De Ita-Pérez


    Full Text Available Daytime restricted feeding (DRF is an experimental protocol that influences the circadian timing system and underlies the expression of a biological clock known as the food entrained oscillator (FEO. Liver is the organ that reacts most rapidly to food restriction by adjusting the functional relationship between the molecular circadian clock and the metabolic networks. γ-Aminobutyric acid (GABA is a signaling molecule in the liver, and able to modulate the cell cycle and apoptosis. This study was aimed at characterizing the expression and activity of the mostly mitochondrial enzyme GABA transaminase (GABA-T during DRF/FEO expression. We found that DRF promotes a sustained increase of GABA-T in the liver homogenate and mitochondrial fraction throughout the entire day-night cycle. The higher amount of GABA-T promoted by DRF was not associated to changes in GABA-T mRNA or GABA-T activity. The GABA-T activity in the mitochondrial fraction even tended to decrease during the light period. We concluded that DRF influences the daily variations of GABA-T mRNA levels, stability, and catalytic activity of GABA-T. These data suggest that the liver GABAergic system responds to a metabolic challenge such as DRF and the concomitant appearance of the FEO.

  19. The dynamics of GABA signaling: Revelations from the circadian pacemaker in the suprachiasmatic nucleus. (United States)

    Albers, H Elliott; Walton, James C; Gamble, Karen L; McNeill, John K; Hummer, Daniel L


    Virtually every neuron within the suprachiasmatic nucleus (SCN) communicates via GABAergic signaling. The extracellular levels of GABA within the SCN are determined by a complex interaction of synthesis and transport, as well as synaptic and non-synaptic release. The response to GABA is mediated by GABAA receptors that respond to both phasic and tonic GABA release and that can produce excitatory as well as inhibitory cellular responses. GABA also influences circadian control through the exclusively inhibitory effects of GABAB receptors. Both GABA and neuropeptide signaling occur within the SCN, although the functional consequences of the interactions of these signals are not well understood. This review considers the role of GABA in the circadian pacemaker, in the mechanisms responsible for the generation of circadian rhythms, in the ability of non-photic stimuli to reset the phase of the pacemaker, and in the ability of the day-night cycle to entrain the pacemaker.

  20. GAD65 is essential for synthesis of GABA destined for tonic inhibition regulating epileptiform activity

    DEFF Research Database (Denmark)

    Walls, Anne B; Nilsen, Linn Hege; Eyjolfsson, Elvar M;


    ABSTRACT: GABA is synthesized from glutamate by glutamate decarboxylase (GAD), which exists in two isoforms, that is, GAD65 and GAD67. In line with GAD65 being located in the GABAergic synapse, several studies have demonstrated that this isoform is important during sustained synaptic transmission....... In contrast, the functional significance of GAD65 in the maintenance of GABA destined for extrasynaptic tonic inhibition is less well studied. Using GAD65-/- and wild type GAD65+/+ mice, this was examined employing the cortical wedge preparation, a model suitable for investigating extrasynaptic GABA......(A) receptor activity. An impaired tonic inhibition in GAD65-/- mice was revealed demonstrating a significant role of GAD65 in the synthesis of GABA acting extrasynaptically. The correlation between an altered tonic inhibition and metabolic events as well as the functional and metabolic role of GABA...

  1. Pesticide Exposure Alters Follicle-Stimulating Hormone Levels in Mexican Agricultural Workers


    Recio, Rogelio; Ocampo-Gómez, Guadalupe; Morán-Martínez, Javier; Borja-Aburto, Victor; López-Cervantes,Malaquías; Uribe, Marisela; Torres-Sánchez, Luisa; Cebrián, Mariano E.


    Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas–liquid chromatography, and serum pituitary and sex hormone levels by...

  2. The role of GABA(A) receptors in the development of alcoholism. (United States)

    Enoch, Mary-Anne


    Alcoholism is a common, heritable, chronic relapsing disorder. GABA(A) receptors undergo allosteric modulation by ethanol, anesthetics, benzodiazepines and neurosteroids and have been implicated in the acute as well as the chronic effects of ethanol including tolerance, dependence and withdrawal. Medications targeting GABA(A) receptors ameliorate the symptoms of acute withdrawal. Ethanol induces plasticity in GABA(A) receptors: tolerance is associated with generally decreased GABA(A) receptor activation and differentially altered subunit expression. The dopamine (DA) mesolimbic reward pathway originating in the ventral tegmental area (VTA), and interacting stress circuitry play an important role in the development of addiction. VTA GABAergic interneurons are the primary inhibitory regulators of DA neurons and a subset of VTA GABA(A) receptors may be implicated in the switch from heavy drinking to dependence. GABA(A) receptors modulate anxiety and response to stress; important elements of sustained drinking and relapse. The GABA(A) receptor subunit genes clustered on chromosome 4 are highly expressed in the reward pathway. Several recent studies have provided strong evidence that one of these genes, GABRA2, is implicated in alcoholism in humans. The influence of the interaction between ethanol and GABA(A) receptors in the reward pathway on the development of alcoholism together with genetic and epigenetic vulnerabilities will be explored in this review.

  3. Neurotransmitters as food supplements: the effects of GABA on brain and behavior. (United States)

    Boonstra, Evert; de Kleijn, Roy; Colzato, Lorenza S; Alkemade, Anneke; Forstmann, Birte U; Nieuwenhuis, Sander


    Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the human cortex. The food supplement version of GABA is widely available online. Although many consumers claim that they experience benefits from the use of these products, it is unclear whether these supplements confer benefits beyond a placebo effect. Currently, the mechanism of action behind these products is unknown. It has long been thought that GABA is unable to cross the blood-brain barrier (BBB), but the studies that have assessed this issue are often contradictory and range widely in their employed methods. Accordingly, future research needs to establish the effects of oral GABA administration on GABA levels in the human brain, for example using magnetic resonance spectroscopy. There is some evidence in favor of a calming effect of GABA food supplements, but most of this evidence was reported by researchers with a potential conflict of interest. We suggest that any veridical effects of GABA food supplements on brain and cognition might be exerted through BBB passage or, more indirectly, via an effect on the enteric nervous system. We conclude that the mechanism of action of GABA food supplements is far from clear, and that further work is needed to establish the behavioral effects of GABA.

  4. Functional properties of GABA synaptic inputs onto GABA neurons in monkey prefrontal cortex

    NARCIS (Netherlands)

    D.C. Rotaru (Diana C.); C. Olezene (Cameron); T. Miyamae (Takeaki); N.V. Povysheva (Nadezhda V.); A.V. Zaitsev (Aleksey V.); D.A. Lewis (David A.); G. Gonzalez-Burgos (Guillermo)


    textabstractIn rodent cortex GABAA receptor (GABAAR)-mediated synapses are a significant source of input onto GABA neurons, and the properties of these inputs vary among GABA neuron subtypes that differ in molecular markers and firing patterns. Some features of cortical interne

  5. Mutations in the GABA Transporter SLC6A1 Cause Epilepsy with Myoclonic-Atonic Seizures

    DEFF Research Database (Denmark)

    Carvill, Gemma L; McMahon, Jacinta M; Schneider, Amy;


    GAT-1, encoded by SLC6A1, is one of the major gamma-aminobutyric acid (GABA) transporters in the brain and is responsible for re-uptake of GABA from the synapse. In this study, targeted resequencing of 644 individuals with epileptic encephalopathies led to the identification of six SLC6A1 mutations...... in seven individuals, all of whom have epilepsy with myoclonic-atonic seizures (MAE). We describe two truncations and four missense alterations, all of which most likely lead to loss of function of GAT-1 and thus reduced GABA re-uptake from the synapse. These individuals share many...



    Watson, Christopher J.; Lydic, Ralph; Baghdoyan, Helen A.


    Morphine, a μ-opioid receptor agonist, is a commonly prescribed treatment for pain. Although highly efficacious, morphine has many unwanted side effects including disruption of sleep and obtundation of wakefulness. One mechanism by which morphine alters sleep and wakefulness may be by modulating GABAergic signaling in brain regions regulating arousal, including the oral pontine reticular formation (PnO). This study used in vivo microdialysis in unanesthetized Sprague-Dawley rat to test the hy...

  7. Segregation of acetylcholine and GABA in the rat superior cervical ganglia: functional correlation.

    Directory of Open Access Journals (Sweden)

    Diana eElinos


    Full Text Available Sympathetic neurons have the capability to segregate their neurotransmitters (NTs and co-transmitters to separate varicosities of single axons; furthermore, in culture, these neurons can even segregate classical transmitters. In vivo sympathetic neurons employ acetylcholine (ACh and other classical NTs such as gamma aminobutyric acid (GABA. Herein, we explore whether these neurons in vivo segregate these classical NTs in the superior cervical ganglia of the rat. We determined the topographical distribution of GABAergic varicosities, somatic GABAA receptor, as well as the regional distribution of the segregation of ACh and GABA. We evaluated possible regional differences in efficacy of ganglionic synaptic transmission, in the sensitivity of GABAA receptor to GABA and to the competitive antagonist picrotoxin (PTX. We found that sympathetic preganglionic neurons in vivo do segregate ACh and GABA. GABAergic varicosities and GABAA receptor expression showed a rostro-caudal gradient along ganglia; in contrast, segregation exhibited a caudo-rostral gradient. These uneven regional distributions in expression of GABA, GABAA receptors, and level segregation correlate with stronger synaptic transmission found in the caudal region. Accordingly, GABAA receptors of rostral region show larger sensitivity to GABA and PTX. These results suggest the presence of different types of GABAA receptors in each region that result in a different regional levels of endogenous GABA inhibition. Finally, we discuss a possible correlation of these different levels of GABA modulation and the function of the target organs innervated by rostral and caudal ganglionic neurons.

  8. Downregulation of GABA[Subscript A] Receptor Protein Subunits a6, ß2, d, e, ?2, ?, and ?2 in Superior Frontal Cortex of Subjects with Autism (United States)

    Fatemi, S. Hossein; Reutiman, Teri J.; Folsom, Timothy D.; Rustan, Oyvind G.; Rooney, Robert J.; Thuras, Paul D.


    We measured protein and mRNA levels for nine gamma-aminobutyric acid A (GABA[subscript A]) receptor subunits in three brain regions (cerebellum, superior frontal cortex, and parietal cortex) in subjects with autism versus matched controls. We observed changes in mRNA for a number of GABA[subscript A] and GABA[subscript B] subunits and overall…

  9. Effect of GABA on oxidative stress in the skeletal muscles and plasma free amino acids in mice fed high-fat diet. (United States)

    Xie, Z X; Xia, S F; Qiao, Y; Shi, Y H; Le, G W


    Increased levels of plasma free amino acids (pFAAs) can disturb the blood glucose levels in patients with obesity, diabetes mellitus and metabolic syndrome (MS) and are associated with enhanced protein oxidation. Oxidation of proteins, especially in the muscles, can promote protein degradation and elevate the levels of pFAAs. Gamma-aminobutyric acid (GABA), a food additive, can reduce high-fat diet (HFD)-induced hyperglycaemia; however, the mechanisms remain unclear. The aim of this study was to evaluate the effects of GABA on protein oxidation and pFAAs changes. One hundred male C57BL/6 mice were randomly divided into five groups that were fed with control diet, HFD and HFD supplied with 0.2%, 0.12% and 0.06% GABA in drinking water for 20 weeks respectively. HFD feeding led to muscular oxidative stress, protein oxidation, pFAA disorders, hyperglycaemia and augmented plasma GABA levels. Treatment with GABA restored normally fasting blood glucose level and dose-dependently inhibited body weight gains, muscular oxidation and protein degradation. While medium and low doses of GABA mitigated HFD-induced pFAA disorders, the high dose of GABA deteriorated the pFAA disorders. Medium dose of GABA increased the levels of GABA, but high dose of GABA reduced the levels of plasma GABA and increased the activity of succinic semialdehyde dehydrogenase in the liver. Therefore, treatment with GABA mitigated HFD-induced hyperglycaemia probably by repairing HFD-induced muscular oxidative stress and pFAA disorders in mice. Our data also suggest that an optimal dose of GABA is crucial for the prevention of excess GABA-related decrease in the levels of pFAA and GABA as well as obesity.

  10. [Influence of exogenous gamma-aminobutyric acid (GABA) on GABA metabolism and amino acid contents in roots of melon seedling under hypoxia stress]. (United States)

    Wang, Chun-Yan; Li, Jing-Rui; Xia, Qing-Ping; Wu, Xiao-Lei; Gao, Hong-Bo


    This paper investigated the influence of gamma-aminobutyric acid (GABA) on GABA metabolism and amino acid content under hypoxia stress by accurately controlling the level of dissolved oxygen in hydroponics, using the roots of melon 'Xiyu 1' seedlings as the test material. The results showed that compared with the control, the growth of roots was inhibited seriously under hypoxia stress. Meanwhile, the hypoxia-treated roots had significantly higher activities of glutamate decarboxylase (GAD), glutamate dehydrogenase (GDH), glutamate synthase (GOGAT), glutamine synthetase (GS), alanine aminotransferase (ALT), aspartate aminotransferase (AST) as well as the contents of GABA, pyruvic acid, alanine (Ala) and aspartic acid (Asp). But the contents of glutamic acid (Glu) and alpha-keto glutaric acid in roots under hypoxia stress was obviously lower than those of the control. Exogenous treatment with GABA alleviated the inhibition effect of hypoxia stress on root growth, which was accompanied by an increase in the contents of endogenous GABA, Glu, alpha-keto glutaric acid and Asp. Furthermore, under hypoxia stress, the activities of GAD, GDH, GOGAT, GS, ALT, AST as well as the contents of pyruvic acid and Ala significantly decreased in roots treated with GABA. However, adding GABA and viny-gamma-aminobutyric acid (VGB) reduced the alleviation effect of GABA on melon seedlings under hypoxia stress. The results suggested that absorption of GABA by roots could alleviate the injury of hypoxia stress to melon seedlings. This meant that GABA treatment allows the normal physiological metabolism under hypoxia by inhibiting the GAD activity through feedback and maintaining higher Glu content as well as the bal- ance of carbon and nitrogen.

  11. Alternative complement pathway and factor B activities in rats with altered blood levels of thyroid hormone

    Energy Technology Data Exchange (ETDEWEB)

    Bitencourt, C.S. [Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Duarte, C.G.; Azzolini, A.E.C.S.; Assis-Pandochi, A.I. [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)


    Evaluating the activity of the complement system under conditions of altered thyroid hormone levels might help elucidate the role of complement in triggering autoimmune processes. Here, we investigated alternative pathway (AP) activity in male Wistar rats (180 ± 10 g) after altering their thyroid hormone levels by treatment with triiodothyronine (T3), propylthiouracil (PTU) or thyroidectomy. T3 and thyroxine (T4) levels were determined by chemiluminescence assays. Hemolytic assays were performed to evaluate the lytic activity of the AP. Factor B activity was evaluated using factor B-deficient serum. An anti-human factor B antibody was used to measure factor B levels in serum by radial immunodiffusion. T3 measurements in thyroidectomized animals or animals treated with PTU demonstrated a significant reduction in hormone levels compared to control. The results showed a reduction in AP lytic activity in rats treated with increasing amounts of T3 (1, 10, or 50 µg). Factor B activity was also decreased in the sera of hyperthyroid rats treated with 1 to 50 µg T3. Additionally, treating rats with 25 µg T3 significantly increased factor B levels in their sera (P < 0.01). In contrast, increased factor B concentration and activity (32%) were observed in hypothyroid rats. We conclude that alterations in thyroid hormone levels affect the activity of the AP and factor B, which may in turn affect the roles of AP and factor B in antibody production.

  12. Alternative complement pathway and factor B activities in rats with altered blood levels of thyroid hormone

    Directory of Open Access Journals (Sweden)

    C.S. Bitencourt


    Full Text Available Evaluating the activity of the complement system under conditions of altered thyroid hormone levels might help elucidate the role of complement in triggering autoimmune processes. Here, we investigated alternative pathway (AP activity in male Wistar rats (180 ± 10 g after altering their thyroid hormone levels by treatment with triiodothyronine (T3, propylthiouracil (PTU or thyroidectomy. T3 and thyroxine (T4 levels were determined by chemiluminescence assays. Hemolytic assays were performed to evaluate the lytic activity of the AP. Factor B activity was evaluated using factor B-deficient serum. An anti-human factor B antibody was used to measure factor B levels in serum by radial immunodiffusion. T3 measurements in thyroidectomized animals or animals treated with PTU demonstrated a significant reduction in hormone levels compared to control. The results showed a reduction in AP lytic activity in rats treated with increasing amounts of T3 (1, 10, or 50 µg. Factor B activity was also decreased in the sera of hyperthyroid rats treated with 1 to 50 µg T3. Additionally, treating rats with 25 µg T3 significantly increased factor B levels in their sera (P < 0.01. In contrast, increased factor B concentration and activity (32% were observed in hypothyroid rats. We conclude that alterations in thyroid hormone levels affect the activity of the AP and factor B, which may in turn affect the roles of AP and factor B in antibody production.

  13. Modulation of cell surface GABA B receptors by desensitization,trafficking and regulated degradation

    Institute of Scientific and Technical Information of China (English)

    Dietmar; Benke; Khaled; Zemoura; Patrick; J; Maier


    Inhibitory neurotransmission ensures normal brain function by counteracting and integrating excitatory activity.-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the mammalian central nervous system,and mediates its effects via two classes of receptors:the GABA A and GABA B receptors.GABA A receptors are heteropentameric GABA-gated chloride channels and responsible for fast inhibitory neurotransmission.GABA B receptors are heterodimeric G protein coupled receptors (GPCR) that mediate slow and prolonged inhibitory transmission.The extent of inhibitory neurotransmission is determined by a variety of factors,such as the degree of transmitter release and changes in receptor activity by posttranslational modifications (e.g.,phosphorylation),as well as by the number of receptors present in the plasma membrane available for signal transduction.The level of GABA B receptors at the cell surface critically depends on the residence time at the cell surface and finally the rates of endocytosis and degradation.In this review we focus primarily on recent advances in the understanding of trafficking mechanisms that determine the expression level of GABA B receptors in the plasma membrane,and thereby signaling strength.

  14. The effects of stiripentol on GABA(A) receptors. (United States)

    Fisher, Janet L


    The anticonvulsant stiripentol (Diacomittm) has been shown to have a positive impact on control of seizures for many patients with Dravet syndrome. As with most antiepileptic drugs, stiripentol has multiple mechanisms of action. Its direct anticonvulsant activity is likely due to enhancement of inhibitory, γ-aminobutyric acid (GABA)ergic neurotransmission. Stiripentol was shown to increase the activity of both neuronal and recombinant GABA(A) receptors at clinically relevant concentrations. At recombinant receptors, stiripentol was found to act through a unique site in a subunit-dependent manner. Positive modulation by stiripentol was most effective at GABA(A) receptors containing an α3 subunit. The expression of the α3 subunit is developmentally regulated, with highest levels in the immature brain. This subunit selectivity may explain the greater clinical efficacy of stiripentol in childhood-onset epilepsies, including Dravet syndrome.

  15. The glutamate/GABA-glutamine cycle

    DEFF Research Database (Denmark)

    Bak, Lasse K; Schousboe, Arne; Waagepetersen, Helle S


    Neurons are metabolically handicapped in the sense that they are not able to perform de novo synthesis of neurotransmitter glutamate and gamma-aminobutyric acid (GABA) from glucose. A metabolite shuttle known as the glutamate/GABA-glutamine cycle describes the release of neurotransmitter glutamate....... Discussions of stoichiometry, the relative role of glutamate vs. GABA and pathological conditions affecting the glutamate/GABA-glutamine cycling are presented. Furthermore, a section is devoted to the accompanying ammonia homeostasis of the glutamate/GABA-glutamine cycle, examining the possible means...... of intercellular transfer of ammonia produced in neurons (when glutamine is deamidated to glutamate) and utilized in astrocytes (for amidation of glutamate) when the glutamate/GABA-glutamine cycle is operating. A main objective of this review is to endorse the view that the glutamate/GABA-glutamine cycle must...

  16. Subtle alterations in NMDA-stimulated cyclic GMP levels following lateral fluid percussion brain injury. (United States)

    Temple, M D; Delahunty, T M; Hamm, R J; Phillips, L L; Lyeth, B G; Povlishock, J T


    This study examined whether NMDA-stimulated cyclic GMP levels were altered at two different time points following lateral fluid percussion injury. At 60 min and 15 days postinjury, the left and right hippocampi were dissected and chopped into mini-prisms. Each hippocampus was divided into five equal parts and incubated with either the phosphodiesterase inhibitor IBMX (3-isobutyl-1-methylxanthine, 500 microM) alone, IBMX and N-methyl-D-aspartic acid (NMDA) OR IBMX, NMDA, and glycine (10 MM). Two concentrations of NMDA were used: 500 or 1,000 microM. Tissues were then assayed for levels of cyclic GMP. Results indicated that there were no changes in basal levels of cyclic GMP at either postinjury time point. At 60 min postinjury, there were no significant main effects for injury or drug concentration. There was a significant injury x side interaction effect with increased levels of NMDA-stimulated cyclic GMP in the hippocampus ipsilateral to the injury impact and decreased cyclic GMP levels in the contralateral hippocampus. There were no significant alterations in NMDA-stimulated cyclic GMP levels at 15 days postinjury. The data from this study indicated that NMDA-stimulated cyclic GMP accumulation is differentially altered in the hippocampus ipsilateral and contralateral to the site of the injury at 1 h after injury, but is normalized by 15 days postinjury. These findings implicate NMDA-mediated intracellular signaling processes in the acute excitotoxic response to injury.

  17. Neurotransmitters as food supplements: the effects of GABA on brain and behavior

    Directory of Open Access Journals (Sweden)

    Evert eBoonstra


    Full Text Available The food supplement version of gamma-aminobutyric acid (GABA is widely available online. Although many consumers claim that they experience benefits from the use of these products, it is unclear whether these supplements confer benefits beyond a placebo effect. Currently, the mechanism of action behind these products is unknown. It has long been thought that GABA is unable to cross the blood brain barrier (BBB, but the studies that have assessed this issue are often contradictory and range widely in their employed methods. Accordingly, future research needs to establish the effects of oral GABA administration on GABA levels in the human brain, for example using magnetic resonance spectroscopy. There is some evidence in favor of a calming effect of GABA food supplements, but most of this evidence was reported by researchers with a potential conflict of interest. We suggest that any veridical effects of GABA food supplements on brain and cognition might be exerted through BBB passage or, more indirectly, via an effect on the enteric nervous system. We conclude that the mechanism of action of GABA food supplements is far from clear, and that further work is needed to establish the behavioral effects of GABA.

  18. Alterations in cytochrome P-450 levels in adult rats following neonatal exposure to xenobiotics

    Energy Technology Data Exchange (ETDEWEB)

    Zangar, R.C. (Oregon State Univ., Corvallis (United States) Pacific Northwest Laboratories, Richland, WA (United States)); Springer, D.L. (Pacific Northwest Laboratories, Richland, WA (United States)); Buhler, D.R. (Oregon State Univ., Corvallis (United States))


    Neonatal exposure to certain xenobiotics has been shown to alter hepatic metabolism in adult rats in a manner that indicates long-term changes in enzyme regulation. Previously, the authors have observed changes in adult testosterone metabolism and in cytochrome P-450 (P-450) mRNA levels in animals neonatally exposed to phenobarbital (PB) or diethylstilbestrol (DES). In order to test for other enzyme alterations, they used Western blot procedures for specific P-450s to analyze hepatic microsomes from adult rats (24 wk old) that had been exposed neonatally to DES, PB, 7,12-dimethylbenz[a]anthracene (DMBA), or pregnenolone 16[alpha]-carbonitrile (PCN). The most striking effects were observed in the DES-treated males: P-4502C6 and an immunologically similar protein were increased 60 and 90%, respectively, relative to control values, but P-4503A2 was decreased by 44%. No changes were observed in the DES-treated males in levels of P-4502E1, P-4502B, or the male-specific P-4502C13. Adult males neonatally treated with PB had 150% increase in levels of anti-P4502B-reactive protein without significant changes in the other enzymes. The DES- and DMBA-treated females had increased levels of the female-specific P-4502C12 of 38 and 48%, respectively, but no other observed alterations. The results confirm that neonatal exposure to DES or PB can cause alterations in adult hepatic cytochrome P-450 levels but show that these chemicals act on different enzymes. Neonatal DMBA resulted in changes in adult females similar to those produced by the synthetic estrogen DES, but did so at about two-thirds lower dose. 37 refs., 5 figs.

  19. Influence of pyridoxal 5'-phosphate alone and in combination with vigabatrin on brain GABA measured by 1H-NMR-spectroscopy. (United States)

    Mueller, S G; Weber, O M; Boesiger, P; Wieser, H G


    Both iso-forms of the gamma-aminobutyric acid (GABA) synthesising enzyme and also the GABA degrading enzyme need pyridoxal 5'-phosphate (PP) as co-enzyme. The aim of the study was to investigate the influence of PP alone and in combination with various doses of vigabatrin (VGB) on brain GABA levels. In eight healthy subjects 300 mg/d PP and various doses of VGB (range, 1000 mg/d to 4000 mg/d) were given alone or in combination. The GABA+/creatine (Cr) signals in both occipital lobes were measured before treatment, during monotherapy with PP or VGB, and during combination of both using 1H-NMR-spectroscopy (1H-NMRS). PP alone did not change the GABA+/Cr signals. VGB alone increased the GABA+/Cr signals in both hemispheres. The combination PP and low-medium dosed VGB (1000-2000 mg/d) did not increase the GABA+/Cr signals. The effects of the combination of PP and high dosed (3000-4000 mg/d) VGB on the GABA+/Cr signals varied depending on the sequence of the drugs and dose of VGB. PP alone has no effect on the GABA+/Cr signals in healthy volunteers. The combination of PP and low-high dosed VGB had inconsistent effects on the GABA+/Cr signals compared to a VGB monotherapy because PP activates also the GABA-degrading enzyme GABA-transaminase.

  20. Interaction between cyclodextrin and neuronal membrane results in modulation of GABA(A) receptor conformational transitions. (United States)

    Pytel, Maria; Mercik, Katarzyna; Mozrzymas, Jerzy W


    Cyclodextrins (CDs) are nanostructures widely applied in biotechnology and chemistry. Owing to partially hydrophobic character, CDs interact with biological membranes. While the mechanisms of CDs interactions with lipids were widely studied, their effects on proteins are less understood. In the present study we investigated the effects of beta cyclodextrin (betaCD) on GABA(A) receptor (GABA(A)R) gating. To reliably resolve the kinetics of conformational transitions, currents were elicited by ultrafast gamma-aminobutyric acid (GABA) applications to outside-out patches from rat cultured hippocampal neurons. betaCD increased the amplitude of responses to saturating GABA concentration ([GABA]) in a dose-dependent manner and this effect was accompanied by profound alterations in the current kinetics. Current deactivation was slowed down by betaCD but this effect was biphasic with a maximum at around 0.5 mM betaCD. While the fast deactivation time constant was monotonically slowed down within considered betaCD concentration range, the slow component first increased and then, at millimolar betaCD concentration, decreased. The rate and extent of desensitization was decreased by betaCD in a dose-dependent manner. The analysis of current responses to nonsaturating [GABA] indicated that betaCD affected the GABA(A)R agonist binding site by slowing down the unbinding rate. Modulation of GABA(A)R desensitization and binding showed different concentration-dependence suggesting different modualtory sites with higher affinity of the latter one. All the betaCD effects were fully reversible indicating that cholesterol uptake into betaCD was not the primary mechanism. We conclude that betaCD is a strong modulator of GABA(A)R conformational transitions.

  1. Alterations in the levels of plasma amino acids in polycystic ovary syndrome- A pilot study

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    Sumithra N Unni C


    Full Text Available Background & objectives: Plasma amino acid levels are known to be altered in conditions like sepsis and burns which are situations of metabolic stress. Polycystic ovary syndrome (PCOS, a condition which affects a woman throughout her life, is said to be associated with metabolic stress. This study was undertaken to assess if there were significant alterations in the levels of plasma amino acids in women with PCOS. Methods: Sixty five women with PCOS along with the similar number of age matched normal controls were included in this study. Levels of 14 amino acids were determined using reverse phase high performance liquid chromatography. Results: The levels of methionine, cystine, isoleucine, phenylalanine, valine, tyrosine, proline, glycine, lysine and histidine were found to be significantly (P<0.001 lower in cases than in controls. Arginine and alanine levels were found to be significantly (P<0.001 higher in cases compared with controls. Interpretation & conclusions: Our findings showed significant derangement in the levels of plasma amino acids in women with PCOS which might be due to the oxidative and metabolic stress associated with it. Further studies need to be done to confirm the findings.

  2. Excitatory action of gamma-aminobutyric acid (GABA) on crustacean neurosecretory cells. (United States)

    García, U; Onetti, C; Valdiosera, R; Aréchiga, H


    1. Intracellular and voltage-clamp recordings were obtained from a selected population of neurosecretory (ns) cells in the X organ of the crayfish isolated eyestalk. Pulses of gamma-aminobutyric acid (GABA) elicited depolarizing responses and bursts of action potentials in a dose-dependent manner. These effects were blocked by picrotoxin (50 microM) but not by bicuculline. Picrotoxin also suppressed spontaneous synaptic activity. 2. The responses to GABA were abolished by severing the neurite of X organ cells, at about 150 microns from the cell body. Responses were larger when the application was made at the neuropil level. 3. Topical application of Cd2+ (2 mM), while suppressing synaptic activity, was incapable of affecting the responses to GABA. 4. Under whole-cell voltage-clamp, GABA elicited an inward current with a reversal potential dependent on the chloride equilibrium potential. The GABA effect was accompanied by an input resistance reduction up to 33% at a -50 mV holding potential. No effect of GABA was detected on potassium, calcium, and sodium currents present in X organ cells. 5. The effect of GABA on steady-state currents was dependent on the intracellular calcium concentration. At 10(-6) M [Ca2+]i, GABA (50 microM) increased the membrane conductance more than threefold and shifted the zero-current potential from -25 to -10 mV. At 10(-9) M [Ca2+]i, GABA induced only a 1.3-fold increase in membrane conductance, without shifting the zero-current potential. 6. These results support the notion that in the population of X organ cells sampled in this study, GABA acts as an excitatory neurotransmitter, opening chloride channels.

  3. High Pressure Germination of Bacillus subtilis Spores with Alterations in Levels and Types of Germination Proteins (United States)


    1ITLE AND SUBTITLE 5a CONTRACTNUMBER High pressure germination of Bacillus subtilis spores with W911NF-09-l-0286 alterations in levels and types of...A moderate high pressure (mHP) of 150 megaPascals (MPa) triggers germination of Bacillus subtilis spores via germinant receptors (GRs), while...germination by a very high pressure (vHP) of550 MPa is GR-independent. The mHP and vHP germination of Bacillus subtilis spores with different levels ofGRs

  4. A new stress model, a scream sound, alters learning and monoamine levels in rat brain. (United States)

    Hu, Lili; Yang, Juan; Song, Tusheng; Hou, Ni; Liu, Yong; Zhao, Xiaoge; Zhang, Dianzeng; Wang, Lumin; Wang, Tao; Huang, Chen


    Most existing animal models for stress involve the simultaneous application of physical and psychological stress factors. In the current study, we described and used a novel psychological stress model (scream sound stress). To study the validity of it, we carried out acute and chronic scream sound stress. First, adult Sprague-Dawley (SD) rats were randomly divided into white noise, stress and background groups. The white noise group and stress group were treated with white noise and scream sound for 4h in the morning respectively. Compared with white noise and background groups, exposure to acute scream sound increased corticosterone (CORT) level and decreased latency in Morris water maze (MWM) test. The levels of noradrenaline (NE), dopamine (DA), 5-hydroxytryptamine (5-HT), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were altered in the striatum, hypothalamus and hippocampus of stress rats. Second, adult SD rats were randomly divided into background and stress groups, which were treated with scream sound for three weeks. Exposure to chronic scream sound suppressed body weight gain, increased corticosterone (CORT) level, influenced the morphology of adrenal gland, improved spleen and thymus indices, and decreased latency in MWM test. NE, DA, DOPAC, HVA and 5-HIAA levels were also altered in the brain of stress rats. Our results suggested that scream sound, as a novel stressor, facilitated learning ability, as well as altered monoamine levels in the rat brain. Moreover, scream sound is easy to apply and can be applied in more animals at the same time.

  5. The Uptake of GABA in Trypanosoma cruzi. (United States)

    Galvez Rojas, Robert L; Ahn, Il-Young; Suárez Mantilla, Brian; Sant'Anna, Celso; Pral, Elizabeth Mieko Furusho; Silber, Ariel Mariano


    Gamma aminobutyric acid (GABA) is widely known as a neurotransmitter and signal transduction molecule found in vertebrates, plants, and some protozoan organisms. However, the presence of GABA and its role in trypanosomatids is unknown. Here, we report the presence of intracellular GABA and the biochemical characterization of its uptake in Trypanosoma cruzi, the etiological agent of Chagas' disease. Kinetic parameters indicated that GABA is taken up by a single transport system in pathogenic and nonpathogenic forms. Temperature dependence assays showed a profile similar to glutamate transport, but the effect of extracellular cations Na(+) , K(+) , and H(+) on GABA uptake differed, suggesting a different uptake mechanism. In contrast to reports for other amino acid transporters in T. cruzi, GABA uptake was Na(+) dependent and increased with pH, with a maximum activity at pH 8.5. The sensitivity to oligomycin showed that GABA uptake is dependent on ATP synthesis. These data point to a secondary active Na(+) /GABA symporter energized by Na(+) -exporting ATPase. Finally, we show that GABA occurs in the parasite's cytoplasm under normal culture conditions, indicating that it is regularly taken up from the culture medium or synthesized through an still undescribed metabolic pathway.

  6. Imbalance between Glutamate and GABA in Fmr1 Knockout Astrocytes Influences Neuronal Development

    Directory of Open Access Journals (Sweden)

    Lu Wang


    Full Text Available Fragile X syndrome (FXS is a form of inherited mental retardation that results from the absence of the fragile X mental retardation protein (FMRP, the product of the Fmr1 gene. Numerous studies have shown that FMRP expression in astrocytes is important in the development of FXS. Although astrocytes affect neuronal dendrite development in Fmr1 knockout (KO mice, the factors released by astrocytes are still unclear. We cultured wild type (WT cortical neurons in astrocyte-conditioned medium (ACM from WT or Fmr1 KO mice. Immunocytochemistry and Western blotting were performed to detect the dendritic growth of both WT and KO neurons. We determined glutamate and γ-aminobutyric acid (GABA levels using high-performance liquid chromatography (HPLC. The total neuronal dendritic length was reduced when cultured in the Fmr1 KO ACM. This neurotoxicity was triggered by an imbalanced release of glutamate and GABA from Fmr1 KO astrocytes. We found increased glutaminase and GABA transaminase (GABA-T expression and decreased monoamine oxidase B expression in Fmr1 KO astrocytes. The elevated levels of glutamate contributed to oxidative stress in the cultured neurons. Vigabatrin (VGB, a GABA-T inhibitor, reversed the changes caused by glutamate and GABA release in Fmr1 KO astrocytes and the abnormal behaviors in Fmr1 KO mice. Our results indicate that the imbalance in the astrocytic glutamate and GABA release may be involved in the neuropathology and the underlying symptoms of FXS, and provides a therapeutic target for treatment.

  7. Imbalance between Glutamate and GABA in Fmr1 Knockout Astrocytes Influences Neuronal Development (United States)

    Wang, Lu; Wang, Yan; Zhou, Shimeng; Yang, Liukun; Shi, Qixin; Li, Yujiao; Zhang, Kun; Yang, Le; Zhao, Minggao; Yang, Qi


    Fragile X syndrome (FXS) is a form of inherited mental retardation that results from the absence of the fragile X mental retardation protein (FMRP), the product of the Fmr1 gene. Numerous studies have shown that FMRP expression in astrocytes is important in the development of FXS. Although astrocytes affect neuronal dendrite development in Fmr1 knockout (KO) mice, the factors released by astrocytes are still unclear. We cultured wild type (WT) cortical neurons in astrocyte-conditioned medium (ACM) from WT or Fmr1 KO mice. Immunocytochemistry and Western blotting were performed to detect the dendritic growth of both WT and KO neurons. We determined glutamate and γ-aminobutyric acid (GABA) levels using high-performance liquid chromatography (HPLC). The total neuronal dendritic length was reduced when cultured in the Fmr1 KO ACM. This neurotoxicity was triggered by an imbalanced release of glutamate and GABA from Fmr1 KO astrocytes. We found increased glutaminase and GABA transaminase (GABA-T) expression and decreased monoamine oxidase B expression in Fmr1 KO astrocytes. The elevated levels of glutamate contributed to oxidative stress in the cultured neurons. Vigabatrin (VGB), a GABA-T inhibitor, reversed the changes caused by glutamate and GABA release in Fmr1 KO astrocytes and the abnormal behaviors in Fmr1 KO mice. Our results indicate that the imbalance in the astrocytic glutamate and GABA release may be involved in the neuropathology and the underlying symptoms of FXS, and provides a therapeutic target for treatment. PMID:27517961

  8. GABA metabolism pathway genes, UGA1 and GAD1, regulate replicative lifespan in Saccharomycescerevisiae

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    Kamei, Yuka; Tamura, Takayuki [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Yoshida, Ryo [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Ohta, Shinji [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Fukusaki, Eiichiro [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mukai, Yukio, E-mail: [Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan)


    Highlights: {yields}We demonstrate that two genes in the yeast GABA metabolism pathway affect aging. {yields} Deletion of the UGA1 or GAD1 genes extends replicative lifespan. {yields} Addition of GABA to wild-type cultures has no effect on lifespan. {yields} Intracellular GABA levels do not differ in longevity mutants and wild-type cells. {yields} Levels of tricarboxylic acid cycle intermediates positively correlate with lifespan. -- Abstract: Many of the genes involved in aging have been identified in organisms ranging from yeast to human. Our previous study showed that deletion of the UGA3 gene-which encodes a zinc-finger transcription factor necessary for {gamma}-aminobutyric acid (GABA)-dependent induction of the UGA1 (GABA aminotransferase), UGA2 (succinate semialdehyde dehydrogenase), and UGA4 (GABA permease) genes-extends replicative lifespan in the budding yeast Saccharomycescerevisiae. Here, we found that deletion of UGA1 lengthened the lifespan, as did deletion of UGA3; in contrast, strains with UGA2 or UGA4 deletions exhibited no lifespan extension. The {Delta}uga1 strain cannot deaminate GABA to succinate semialdehyde. Deletion of GAD1, which encodes the glutamate decarboxylase that converts glutamate into GABA, also increased lifespan. Therefore, two genes in the GABA metabolism pathway, UGA1 and GAD1, were identified as aging genes. Unexpectedly, intracellular GABA levels in mutant cells (except for {Delta}uga2 cells) did not differ from those in wild-type cells. Addition of GABA to culture media, which induces transcription of the UGA structural genes, had no effect on replicative lifespan of wild-type cells. Multivariate analysis of {sup 1}H nuclear magnetic resonance spectra for the whole-cell metabolite levels demonstrated a separation between long-lived and normal-lived strains. Gas chromatography-mass spectrometry analysis of identified metabolites showed that levels of tricarboxylic acid cycle intermediates positively correlated with lifespan

  9. GABA in Paraventricular Nucleus Regulates Adipose Afferent Reflex in Rats.

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    Lei Ding

    Full Text Available Chemical stimulation of white adipose tissue (WAT induces adipose afferent reflex (AAR, and thereby causes a general sympathetic activation. Paraventricular nucleus (PVN is important in control of sympathetic outflow. This study was designed to investigate the role of γ-aminobutyric acid (GABA in PVN in regulating the AAR.Experiments were carried out in anesthetized rats. Renal sympathetic nerve activity (RSNA and mean arterial pressure (MAP were continuously recorded. AAR was evaluated by the RSNA and MAP responses to electrical stimulation of the right epididymal WAT (eWAT afferent nerve. Electrical stimulation of eWAT afferent nerve increase RSNA. Bilateral microinjection of the GABAA receptor agonist isoguvacine or the GABAB receptor agonist baclofen attenuated the AAR. The effect of isoguvacine on the AAR was greater than that of baclofen. The GABAA receptor antagonist gabazine enhanced the AAR, while the GABAB receptor antagonist CGP-35348 had no significant effect on the AAR. Bilateral PVN microinjection of vigabatrin, a selective GABA-transaminase inhibitor, to increase endogenous GABA levels in the PVN abolished the AAR. The inhibitory effect of vigabatrin on the AAR was attenuated by the pretreatment with gabazine or CGP-35348. Pretreatment with combined gabazine and CGP-35348 abolished the effects of vigabatrin.Activation of GABAA or GABAB receptors in the PVN inhibits the AAR. Blockade of GABAA receptors in the PVN enhances the AAR. Endogenous GABA in the PVN plays an important role in regulating the AAR.

  10. GABA not only a neurotransmitter: osmotic regulation by GABAAR signalling

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    Tiziana eCesetti


    Full Text Available In neurons the anionic channel γ-aminobutyric (GABA A receptor (GABAAR plays a central role in mediating both the neurotrophic and neurotransmitter role of GABA. Activation of this receptor by GABA also affects the function of non-neuronal cells in the central nervous system (CNS, as GABAARs are expressed in mature macroglia and in almost all progenitor types, including neural stem cells. The relevance of GABA signalling in non-neuronal cells has been comparatively less investigated than in neurons. However, it is becoming increasingly evident that these cells are direct targets of GABA regulation. In non-neuronal cells GABAAR activation leads to influx or efflux of chloride (Cl- depending on the electrochemical gradient. Ion transport is indissolubly associated to water fluxes across the plasma membrane and plays a key role in brain physiology. Therefore, GABAAR could affect osmotic tension in the brain by modulating ion gradients. In addition, since water movements also occur through specialized water channels and transporters, GABAAR signalling could affect the movement of water also by regulating the function of the channels and transporters involved, thereby affecting not only the direction of the water fluxes but also their dynamics. This regulation has consequences at the cellular level as it modulates cell volume and activates multiple intracellular signalling mechanisms important for cell proliferation, maturation and survival. It may also have consequences at the systemic level. For example, it may indirectly control neuronal excitability, by regulating the extracellular space and interstitial concentration of Cl-, and contribute to brain water homeostasis. Therefore, GABAergic osmotic regulation should be taken into account during the treatment of pathologies requiring the administration of GABAAR modulators and for the development of therapies for diseases causing water unbalance in the brain.

  11. Exogenous γ-aminobutyric acid (GABA) affects pollen tube growth via modulating putative Ca2+-permeable membrane channels and is coupled to negative regulation on glutamate decarboxylase. (United States)

    Yu, Guang-Hui; Zou, Jie; Feng, Jing; Peng, Xiong-Bo; Wu, Ju-You; Wu, Ying-Liang; Palanivelu, Ravishankar; Sun, Meng-Xiang


    γ-Aminobutyric acid (GABA) is implicated in pollen tube growth, but the molecular and cellular mechanisms that it mediates are largely unknown. Here, it is shown that exogenous GABA modulates putative Ca(2+)-permeable channels on the plasma membranes of tobacco pollen grains and pollen tubes. Whole-cell voltage-clamp experiments and non-invasive micromeasurement technology (NMT) revealed that the influx of Ca(2+) increases in pollen tubes in response to exogenous GABA. It is also demonstrated that glutamate decarboxylase (GAD), the rate-limiting enzyme of GABA biosynthesis, is involved in feedback controls of Ca(2+)-permeable channels to fluctuate intracellular GABA levels and thus modulate pollen tube growth. The findings suggest that GAD activity linked with Ca(2+)-permeable channels relays an extracellular GABA signal and integrates multiple signal pathways to modulate tobacco pollen tube growth. Thus, the data explain how GABA mediates the communication between the style and the growing pollen tubes.

  12. Selective GABA transporter inhibitors tiagabine and EF1502 exhibit mechanistic differences in their ability to modulate the ataxia and anticonvulsant action of the extrasynaptic GABA(A) receptor agonist gaboxadol

    DEFF Research Database (Denmark)

    Madsen, Karsten Kirkegaard; Ebert, Bjarke; Clausen, Rasmus Prætorius


    Modulation of the extracellular levels of GABA via inhibition of the synaptic GABA transporter GAT1 by the clinically effective and selective GAT1 inhibitor tiagabine [(R)-N-[4,4-bis(3-methyl-2-thienyl)-3-butenyl]nipecotic acid; Gabitril] has proven to be an effective treatment strategy for focal...

  13. Determination and comparison of γ-aminobutyric acid (GABA) content in pu-erh and other types of Chinese tea. (United States)

    Zhao, Ming; Ma, Yan; Wei, Zhen-zhen; Yuan, Wen-xia; Li, Ya-li; Zhang, Chun-hua; Xue, Xiao-ting; Zhou, Hong-jie


    Two previous studies have reported that pu-erh tea contains a high level of γ-aminobutyric acid (GABA), which is the major inhibitory neurotransmitter in the central nervous system and has several physiological functions. However, two other researchers have demonstrated that the GABA content of several pu-erh teas was low. Due to the high value and health benefits of GABA, analysis of mass-produced pu-erh tea is necessary to determine whether it is actually enriched with GABA. A high-performance liquid chromatography (HPLC) method was developed for the determination of GABA in tea, the results of which were verified by amino acid analysis using an Amino Acid Analyzer (AAA). A total of 114 samples of various types of Chinese tea, including 62 pu-erh teas, 13 green teas, 8 oolong teas, 8 black teas, 3 white teas, 4 GABA teas, and 16 process samples from two industrial fermentations of pu-erh tea (including the raw material and the first to seventh turnings), were analyzed using HPLC. Statistical analysis demonstrated that the GABA content in pu-erh tea was significantly lower than that in other types of tea (p content decreased during industrial fermentation of pu-erh tea (p content in pu-erh tea. In addition, the GABA content in white tea was found to be significantly higher than that in the other types of tea (p < 0.05), leading to the possibility of producing GABA-enriched white tea.

  14. GABA uptake into astrocytes is not associated with significant metabolic cost: implications for brain imaging of inhibitory transmission. (United States)

    Chatton, Jean-Yves; Pellerin, Luc; Magistretti, Pierre J


    Synaptically released glutamate has been identified as a signal coupling excitatory neuronal activity to increased glucose utilization. The proposed mechanism of this coupling involves glutamate uptake into astrocytes resulting in increased intracellular Na+ (Nai+) and activation of the Na+/K+-ATPase. Increased metabolic demand linked to disruption of Nai+ homeostasis activates glucose uptake and glycolysis in astrocytes. Here, we have examined whether a similar neurometabolic coupling could operate for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), also taken up by Na+-dependent transporters into astrocytes. Thus, we have compared the Nai+ response to GABA and glutamate in mouse astrocytes by microspectrofluorimetry. The Nai+ response to GABA consisted of a rapid rise of 4-6 mM followed by a plateau that did not, however, significantly activate the pump. Indeed, the GABA transporter-evoked Na+ influxes are transient in nature, almost totally shutting off within approximately 30 sec of GABA application. The metabolic consequences of the GABA-induced Nai+ response were evaluated by monitoring cellular ATP changes indirectly in single cells and measuring 2-deoxyglucose uptake in astrocyte populations. Both approaches showed that, whereas glutamate induced a robust metabolic response in astrocytes (decreased ATP levels and glucose uptake stimulation), GABA did not cause any measurable metabolic response, consistent with the Nai+ measurements. Results indicate that GABA does not couple inhibitory neuronal activity with glucose utilization, as does glutamate for excitatory neurotransmission, and suggest that GABA-mediated synaptic transmission does not contribute directly to brain imaging signals based on deoxyglucose.

  15. Modulation of ROS levels in fibroblasts by altering mitochondria regulates the process of wound healing. (United States)

    Janda, Jaroslav; Nfonsam, Valentine; Calienes, Fernanda; Sligh, James E; Jandova, Jana


    Mitochondria are the major source of reactive oxygen species (ROS) in fibroblasts which are thought to be crucial regulators of wound healing with a potential to affect the expression of nuclear genes involved in this process. ROS generated by mitochondria are involved in all stages of tissue repair process but the regulation of ROS-generating system in fibroblasts still remains poorly understood. The purpose of this study was to better understand molecular mechanisms of how the regulation of ROS levels generated by mitochondria may influence the process of wound repair. Cybrid model system of mtDNA variations was used to study the functional consequences of altered ROS levels on wound healing responses in a uniform nuclear background of cultured ρ(0) fibroblasts. Mitochondrial ROS in cybrids were modulated by antioxidants that quench ROS to examine their ability to close the wound. Real-time PCR arrays were used to investigate whether ROS generated by specific mtDNA variants have the ability to alter expression of some key nuclear-encoded genes central to the wound healing response and oxidative stress. Our data suggest levels of mitochondrial ROS affect expression of some nuclear encoded genes central to wound healing response and oxidative stress and modulation of mitochondrial ROS by antioxidants positively affects in vitro process of wound closure. Thus, regulation of mitochondrial ROS-generating system in fibroblasts can be used as effective natural redox-based strategy to help treat non-healing wounds.

  16. Hypothesis/review: contribution of putrescine to 4-aminobutyrate (GABA) production in response to abiotic stress. (United States)

    Shelp, Barry J; Bozzo, Gale G; Trobacher, Christopher P; Zarei, Adel; Deyman, Kristen L; Brikis, Carolyne J


    4-Aminobutyrate (GABA) accumulates in various plant parts, including bulky fruits such as apples, in response to abiotic stress. It is generally believed that the GABA is derived from glutamate, although a contribution from polyamines is possible. Putrescine, but not spermidine and spermine, generally accumulates in response to the genetic manipulation of polyamine biosynthetic enzymes and abiotic stress. However, the GABA levels in stressed plants are influenced by processes other than putrescine availability. It is hypothesized that the catabolism of putrescine to GABA is regulated by a combination of gene-dependent and -independent processes. The expression of several putative diamine oxidase genes is weak, but highly stress-inducible in certain tissues of Arabidopsis. In contrast, candidate genes that encode 4-aminobutyraldehyde dehydrogenase are highly constitutive, but not stress inducible. Changes in O(2) availability and cellular redox balance due to stress may directly influence the activities of diamine oxidase and 4-aminobutyraldehyde dehydrogenase, thereby restricting GABA formation. Apple fruit is known to accumulate GABA under controlled atmosphere storage and therefore could serve as a model system for investigating the relative contribution of putrescine and glutamate to GABA production.

  17. Prevention of GABA reduction during dough fermentation using a baker's yeast dal81 mutant. (United States)

    Ando, Akira; Nakamura, Toshihide


    γ-Aminobutyric acid (GABA) is consumed by yeasts during fermentation. To prevent GABA reduction in bread dough, a baker's yeast mutant AY77 deficient in GABA assimilation was characterized and utilized for wheat dough fermentation. An amber mutation in the DAL81 gene, which codes for a positive regulator of multiple nitrogen degradation pathways, was found in the AY77 strain. The qPCR analyses of genes involved in nitrogen utilization showed that transcriptional levels of the UGA1 and DUR3 genes encoding GABA transaminase and urea transporter, respectively, are severely decreased in the AY77 cells. The AY77 strain cultivated by fed-batch culture using cane molasses exhibited inferior gas production during dough fermentation compared to that of wild-type strain AY13. However, when fed with molasses containing 0.5% ammonium sulfate, the mutant strain exhibited gas production comparable to that of the AY13 strain. In contrast to the AY13 strain, which completely consumed GABA in dough within 5 h, the AY77 strain consumed no GABA under either culture condition. Dough fermentation with the dal81 mutant strain should be useful for suppression of GABA reduction in breads.

  18. Local and global ligand-induced changes in the structure of the GABA(A) receptor. (United States)

    Muroi, Yukiko; Czajkowski, Cynthia; Jackson, Meyer B


    Ligand-gated channels mediate synaptic transmission through conformational transitions triggered by the binding of neurotransmitters. These transitions are well-defined in terms of ion conductance, but their structural basis is poorly understood. To probe these changes in structure, GABA(A) receptors were expressed in Xenopus oocytes and labeled at selected sites with environment-sensitive fluorophores. With labels at two different residues in the alpha1 subunit in loop E of the GABA-binding pocket, GABA elicited fluorescence changes opposite in sign. This pattern of fluorescence changes is consistent with a closure of the GABA-binding cavity at the subunit interface. The competitive antagonist SR-95531 inverted this pattern of fluorescence change, but the noncompetitive antagonist picrotoxin failed to elicit optical signals. In response to GABA (but not SR-95531), labels at the homologous residues in the beta2 subunit showed the same pattern of fluorescence change as the alpha1-subunit labels, indicating a global transition with comparable movements in homologous regions of different subunits. Incorporation of the gamma2 subunit altered the fluorescence changes of alpha1-subunit labels and eliminated them in beta2-subunit labels. Thus, the ligand-induced structural changes in the GABA(A) receptor can extend over considerable distances or remain highly localized, depending upon subunit composition and ligand.

  19. Methoxychlor reduces estradiol levels by altering steroidogenesis and metabolism in mouse antral follicles in vitro. (United States)

    Basavarajappa, Mallikarjuna S; Craig, Zelieann R; Hernández-Ochoa, Isabel; Paulose, Tessie; Leslie, Traci C; Flaws, Jodi A


    The organochlorine pesticide methoxychlor (MXC) is a known endocrine disruptor that affects adult rodent females by causing reduced fertility, persistent estrus, and ovarian atrophy. Since MXC is also known to target antral follicles, the major producer of sex steroids in the ovary, the present study was designed to test the hypothesis that MXC decreases estradiol (E₂) levels by altering steroidogenic and metabolic enzymes in the antral follicles. To test this hypothesis, antral follicles were isolated from CD-1 mouse ovaries and cultured with either dimethylsulfoxide (DMSO) or MXC. Follicle growth was measured every 24 h for 96 h. In addition, sex steroid hormone levels were measured using enzyme-linked immunosorbent assays (ELISA) and mRNA expression levels of steroidogenic enzymes as well as the E₂ metabolic enzyme Cyp1b1 were measured using qPCR. The results indicate that MXC decreased E₂, testosterone, androstenedione, and progesterone (P₄) levels compared to DMSO. In addition, MXC decreased expression of aromatase (Cyp19a1), 17β-hydroxysteroid dehydrogenase 1 (Hsd17b1), 17α-hydroxylase/17,20-lyase (Cyp17a1), 3β hydroxysteroid dehydrogenase 1 (Hsd3b1), cholesterol side-chain cleavage (Cyp11a1), steroid acute regulatory protein (Star), and increased expression of Cyp1b1 enzyme levels. Thus, these data suggest that MXC decreases steroidogenic enzyme levels, increases metabolic enzyme expression and this in turn leads to decreased sex steroid hormone levels.

  20. [A new role of GABA on synapses]. (United States)

    Hayama, Tatsuya; Kasai, Haruo


    Neurons connect and transmit information via synapses. The major excitatory and inhibitory (E-I) neurotransmitters are glutamate and γ-amino butyric acid (GABA), respectively. The E-I balance plays an important role in various brain functions. In this review, we summarize the role of GABA on synaptic integration and synaptic plasticity by introducing our own recent findings. In synaptic integration, GABA is considered to inhibit depolarization induced by glutamate and suppress action potentials. We found that GABA also has a more direct role on the synaptic plasticity of excitatory inputs. GABA effectively promotes the shrinkage and elimination of synapses by suppressing local dendritic Ca(2+) signaling, while keeping the Ca(2+) domain of the NMDA receptors intact. In this manner, GABA promoted the activation of calcineurin, which in turn activated cofilin. Interestingly, shrinkage tended to spread, likely due to the spread of cofilin, and induced competitive selection of synapses via its phosphorylation and dephosphorylation. The selection of synapses is key to the reorganization of the central nervous system during development and in adulthood, and GABA plays key roles in various mental disorders, such as autism and schizophrenia. Our results account well for the in vivo GABA functions on synaptic selection, and may help to develop new therapeutic compounds.

  1. GABA localization in the nematode Ascaris

    Energy Technology Data Exchange (ETDEWEB)

    Guastella, J.


    A histochemical approach was used to examine the distribution of GABA-associated neurons in the nematode Ascaris, an organism whose small number of morphologically simple neurons make it an excellent preparation for analyzing neuronal phenotypes. Two GABAergic markers were examined: GABA-like immunoreactivity (GLIR), a marker for endogenous stores of GABA; and ({sup 3}H)-GABA uptake, a marker for GABA uptake sites. Strong GLIR was present in the cell bodies, neurites and commissures of dorsal and ventral inhibitory motorneurons present in this region. Strong GLIR was also present in the cell bodies and processes of the four RME neurons in the nerve ring and in several other ganglionic neurons. Staining was absent in excitatory motorneurons, in ventral cord interneurons and in muscle cells and hypodermis. GABA uptake sites were found in single neural processes in both the ventral and dorsal nerve cords. ({sup 3}H)-GABA labeling was also observed in the other two RME cells and several other cephalic neurons. Four putative cholinergic excitatory motorneurons in the retrovesicular ganglion (RVG) were heavily labeled. Ventral and dorsal nerve cord inhibitory motorneurons did not take up ({sup 3}H)-GABA. Labeling of the ventral cord excitatory motorneuron somata and cell bodies was at or slightly above background. Heavy labeling of muscle cells was also observed.

  2. Autism associated gene, engrailed2, and flanking gene levels are altered in post-mortem cerebellum.

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    Jiyeon Choi

    Full Text Available BACKGROUND: Previous genetic studies demonstrated association between the transcription factor engrailed2 (EN2 and Autism Spectrum Disorder (ASD. Subsequent molecular analysis determined that the EN2 ASD-associated haplotype (rs1861972-rs1861973 A-C functions as a transcriptional activator to increase gene expression. EN2 is flanked by 5 genes, serotonin receptor5a (HTR5A, insulin induced gene1 (INSIG1, canopy1 homolog (CNPY1, RNA binding motif protein33 (RBM33, and sonic hedgehog (SHH. These flanking genes are co-expressed with EN2 during development and coordinate similar developmental processes. To investigate if mRNA levels for these genes are altered in individuals with autism, post-mortem analysis was performed. METHODS: qRT-PCR quantified mRNA levels for EN2 and the 5 flanking genes in 78 post-mortem cerebellar samples. mRNA levels were correlated with both affection status and rs1861972-rs1861973 genotype. Molecular analysis investigated whether EN2 regulates flanking gene expression. RESULTS: EN2 levels are increased in affected A-C/G-T individuals (p = .0077. Affected individuals also display a significant increase in SHH and a decrease in INSIG1 levels. Rs1861972-rs1861973 genotype is correlated with significant increases for SHH (A-C/G-T and CNPY1 (G-T/G-T levels. Human cell line over-expression and knock-down as well as mouse knock-out analysis are consistent with EN2 and SHH being co-regulated, which provides a possible mechanism for increased SHH post-mortem levels. CONCLUSIONS: EN2 levels are increased in affected individuals with an A-C/G-T genotype, supporting EN2 as an ASD susceptibility gene. SHH, CNPY1, and INSIG1 levels are also significantly altered depending upon affection status or rs1861972-rs1861973 genotype. Increased EN2 levels likely contribute to elevated SHH expression observed in the post-mortem samples.

  3. Steroid levels in crinoid echinoderms are altered by exposure to model endocrine disruptors. (United States)

    Lavado, Ramón; Barbaglio, Alice; Carnevali, M Daniela Candia; Porte, Cinta


    Sexual steroids (testosterone and estradiol) were measured in the whole body of wild specimens of the crinoid Antedon mediterranea collected from the Tyrrhenian Sea (Italy). Testosterone levels (274-1,488 pg/g wet weight (w.w.)) were higher than those of estradiol (60-442 pg/g w.w.) and no significant differences between males and females were observed. No clear seasonal trend was either detected - individuals from February, June and October 2004 analyzed - apart from a peak of estradiol in males in autumn. Nonetheless, dramatic changes on tissue steroid levels were observed when individuals were exposed to model androgenic and anti-androgenic compounds for 2 and 4 weeks. The selected compounds were 17 alpha-methyltestosterone (17 alpha-MT), triphenyltin (TPT), fenarimol (FEN), cyproterone acetate (CPA), and p,p'-DDE. Endogenous testosterone levels were significantly increased after exposure to 17 alpha-MT, TPT and FEN, while different responses were observed for estradiol; 17 alpha-MT and FEN increased endogenous estradiol (up to seven-fold), and TPT lead to a significant decrease. Concerning the anti-androgenic compounds, CPA significantly reduced testosterone in a dose-dependent manner without altering estradiol levels, whereas specimens exposed to p,p'-DDE at a low dose (24 ng/L) for 4 weeks showed a four-fold increase in T levels. Overall, the data show the ability of the selected compounds to alter endogenous steroid concentrations in A. mediterranea, and suggest the existence in this echinoderm species of vertebrate-like mechanisms that can be affected by exposure to androgenic and anti-androgenic chemicals.

  4. Mineral abundances and different levels of alteration around Mawrth Vallis, Mars

    Institute of Scientific and Technical Information of China (English)

    Sheng Gou; Zongyu Yue; Kaichang Di; Jinnian Wang


    Spectral indices from OMEGA hyperspectral data show that there are two main phyllosilicates exposed in and around Mawrth Vallis: Al phyllosilicates and Fe/Mg phyllosilicates. Detailed analysis of CRISM spectra shows that Al phyllosilicates such as montmorillonite, hydrated silica, kaolinite; Fe/Mg phyllo-silicates such as nontronite, saponite, serpentine are widespread on the light-toned outcrops. Though similar stratigraphical sequences, morphologies and textures are observed on both sides of Mawrth Vallis from HiRISE images, suggesting that the geological processes that formed these units must have operated at a regional scale; the multiple endmember spectral mixture analysis (MESMA) derived mineral abundance indicates that there is a higher level of alteration in the western side relative to the eastern side. We suggest that the observed phyllosilicates, stratigraphical sequences and different levels of alteration might have been caused by sedimentary deposition processes in which the composition of the external source sediment or the local solution was different, or by a pedogenic process closely related to the leaching of abundant liquid water with different chemical properties.

  5. Alterations of BDNF and GDNF serum levels in alcohol-addicted patients during alcohol withdrawal

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    Mehmet Bülent Sönmez

    Full Text Available Background and Objectives: Brain-derived neurotrophic factor (BDNF and glial cell line-derived neurotrophic factor (GDNF are neurotrophic neuropeptides that play important roles in the synaptic plasticity, neuronal growth, survival and function. A possible neuroprotective role of neurotrophic factors against alcohol-induced cell damage has been suggested, and dysregulations in neurotrophic factors may be involved in the vulnerability to addiction. The aim of this study was to investigate the alterations of BDNF and GDNF serum levels in alcohol-addicted patients during alcohol withdrawal compared to healthy controls. Methods: BDNF and GDNF serum levels of 34 male inpatients diagnosed with alcohol addiction according to DSM-IV-TR were investigated during alcohol withdrawal (day 1, 7 and 14 in comparison to 32 healthy controls using an enzyme-linked immunosorbent assay (ELISA. Severity of alcohol withdrawal was measured by Clinical Institute Withdrawal Assessment for Alcohol (CIWA-Ar, and intensity of alcohol craving was measured by Penn Alcohol Craving Scale (PACS during alcohol withdrawal (day 1, 7 and 14. Results: BDNF serum levels increased significantly during alcohol withdrawal (p = 0.020. They were negatively correlated to the severity of alcohol withdrawal, and the correlation was close to being statistically significant (p = 0.058. BDNF and GDNF serum levels did not differ significantly between the patient and control groups. GDNF serum levels did not change significantly during alcohol withdrawal. Conclusions: Our results may provide support for the previously hypothesized role of BDNF in the neuroadaptation during alcohol withdrawal.

  6. Audiovisual associations alter the perception of low-level visual motion

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    Hulusi eKafaligonul


    Full Text Available Motion perception is a pervasive nature of vision and is affected by both immediate pattern of sensory inputs and prior experiences acquired through associations. Recently, several studies reported that an association can be established quickly between directions of visual motion and static sounds of distinct frequencies. After the association is formed, sounds are able to change the perceived direction of visual motion. To determine whether such rapidly acquired audiovisual associations and their subsequent influences on visual motion perception are dependent on the involvement of higher-order attentive tracking mechanisms, we designed psychophysical experiments using regular and reverse-phi random dot motions isolating low-level pre-attentive motion processing. Our results show that an association between the directions of low-level visual motion and static sounds can be formed and this audiovisual association alters the subsequent perception of low-level visual motion. These findings support the view that audiovisual associations are not restricted to high-level attention based motion system and early-level visual motion processing has some potential role.

  7. Audiovisual associations alter the perception of low-level visual motion. (United States)

    Kafaligonul, Hulusi; Oluk, Can


    Motion perception is a pervasive nature of vision and is affected by both immediate pattern of sensory inputs and prior experiences acquired through associations. Recently, several studies reported that an association can be established quickly between directions of visual motion and static sounds of distinct frequencies. After the association is formed, sounds are able to change the perceived direction of visual motion. To determine whether such rapidly acquired audiovisual associations and their subsequent influences on visual motion perception are dependent on the involvement of higher-order attentive tracking mechanisms, we designed psychophysical experiments using regular and reverse-phi random dot motions isolating low-level pre-attentive motion processing. Our results show that an association between the directions of low-level visual motion and static sounds can be formed and this audiovisual association alters the subsequent perception of low-level visual motion. These findings support the view that audiovisual associations are not restricted to high-level attention based motion system and early-level visual motion processing has some potential role.

  8. Effects of glutamate decarboxylase and gamma-aminobutyric acid (GABA) transporter on the bioconversion of GABA in engineered Escherichia coli. (United States)

    Le Vo, Tam Dinh; Kim, Tae Wan; Hong, Soon Ho


    Gamma-aminobutyric acid (GABA) is a non-essential amino acid and a precursor of pyrrolidone, a monomer of nylon 4. GABA can be biosynthesized through the decarboxylation of L: -glutamate by glutamate decarboxylase. In this study, the effects of glutamate decarboxylase (gadA, gadB), glutamate/GABA antiporter (gadC) and GABA aminotransferase (gabT) on GABA production were investigated in Escherichia coli. Glutamate decarboxylase was overexpressed alone or with the glutamate/GABA antiporter to enhance GABA synthesis. GABA aminotransferase, which redirects GABA into the TCA cycle, was knock-out mutated. When gadB and gadC were co-overexpressed in the gabT mutant strain, a final GABA concentration of 5.46 g/l was obtained from 10 g/l of monosodium glutamate (MSG), which corresponded to a GABA yield of 89.5%.

  9. Allodynia and hyperalgesia in diabetic rats are mediated by GABA and depletion of spinal potassium-chloride co-transporters. (United States)

    Jolivalt, Corinne G; Lee, Corinne A; Ramos, Khara M; Calcutt, Nigel A


    Diabetic rats show behavioral indices of painful neuropathy that may model the human condition. Hyperalgesia during the formalin test in diabetic rats is accompanied by the apparently paradoxical decrease in spinal release of excitatory neurotransmitters and increase in the inhibitory neurotransmitter GABA. Decreased expression of the potassium-chloride co-transporter, KCC2, in the spinal cord promotes excitatory properties of GABA. We therefore measured spinal KCC2 expression and explored the role of the GABA(A) receptor in rats with painful diabetic neuropathy. KCC2 protein levels were significantly reduced in the spinal cord of diabetic rats, while levels of NKCC1 and the GABA(A) receptor were unchanged. Spinal delivery of the GABA(A) receptor antagonist bicuculline reduced formalin-evoked flinching in diabetic rats and also dose-dependently alleviated tactile allodynia. GABA(A) receptor-mediated rate-dependent depression of the spinal H reflex was absent in the spinal cord of diabetic rats. Control rats treated with the KCC2 blocker DIOA, mimicked diabetes by showing increased formalin-evoked flinching and diminished rate- dependent depression. The ability of bicuculline to alleviate allodynia and formalin-evoked hyperalgesia in diabetic rats is consistent with a reversal of the properties of GABA predicted by reduced spinal KCC2 and suggests that reduced KCC2 expression and increased GABA release contribute to spinally mediated hyperalgesia in diabetes.

  10. Saharan dust inputs and high UVR levels jointly alter the metabolic balance of marine oligotrophic ecosystems (United States)

    Cabrerizo, Marco J.; Medina-Sánchez, Juan Manuel; González-Olalla, Juan Manuel; Villar-Argaiz, Manuel; Carrillo, Presentación


    The metabolic balance of the most extensive bioma on the Earth is a controversial topic of the global-change research. High ultraviolet radiation (UVR) levels by the shoaling of upper mixed layers and increasing atmospheric dust deposition from arid regions may unpredictably alter the metabolic state of marine oligotrophic ecosystems. We performed an observational study across the south-western (SW) Mediterranean Sea to assess the planktonic metabolic balance and a microcosm experiment in two contrasting areas, heterotrophic nearshore and autotrophic open sea, to test whether a combined UVR × dust impact could alter their metabolic balance at mid-term scales. We show that the metabolic state of oligotrophic areas geographically varies and that the joint impact of UVR and dust inputs prompted a strong change towards autotrophic metabolism. We propose that this metabolic response could be accentuated with the global change as remote-sensing evidence shows increasing intensities, frequencies and number of dust events together with variations in the surface UVR fluxes on SW Mediterranean Sea. Overall, these findings suggest that the enhancement of the net carbon budget under a combined UVR and dust inputs impact could contribute to boost the biological pump, reinforcing the role of the oligotrophic marine ecosystems as CO2 sinks.

  11. Exposure to novelty and forced swimming evoke stressor-dependent changes in extracellular GABA in the rat hippocampus. (United States)

    de Groote, L; Linthorst, A C E


    In the hippocampus, a brain structure critically important in the stress response, GABA controls neuronal activity not only via synaptic inhibition, but also via tonic inhibition through stimulation of extrasynaptic GABA receptors. The extracellular level of GABA may represent a major determinant for tonic inhibition and, therefore, it is surprising that its responsiveness to stress has hardly been investigated. To clarify whether hippocampal extracellular GABA levels change in response to acute stress, we conducted an in vivo microdialysis study in rats. We found that dialysate GABA levels respond to various neuropharmacological manipulations such as reuptake inhibition, elevated concentrations of K(+), tetrodotoxin and baclofen, indicating that a large proportion of hippocampal extracellular GABA depends on neuronal release and that GABA re-uptake plays a role in determining the extracellular levels of this neurotransmitter. Next, rats were exposed to a novel cage or to forced swimming in 25 degrees C water. Interestingly, these two stressors resulted in opposite effects. Novelty caused a fast increase in GABA (120% of baseline), whereas forced swimming resulted in a profound decrease (70% of baseline). To discriminate between the psychological and physical aspects (i.e. the effects on body temperature) of forced swimming, another group of animals was forced to swim at 35 degrees C. This stressor, like novelty, caused an increase in hippocampal GABA, suggesting a stimulatory effect of psychological stress. The effects of novelty could not be blocked by the corticotropin-releasing factor receptor antagonist D-Phe-CRF(12-41). These results are the first to demonstrate stressor-dependent changes in hippocampal extracellular GABA; an observation which may be of particular significance for GABAergic tonic inhibition of hippocampal neurons.

  12. Alteration of plasma glutamate and glutamine levels in children with high-functioning autism.

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    Chie Shimmura

    Full Text Available BACKGROUND: It has recently been hypothesized that hyperglutamatergia in the brain is involved in the pathophysiology of autism. However, there is no conclusive evidence of the validity of this hypothesis. As peripheral glutamate/glutamine levels have been reported to be correlated with those of the central nervous system, the authors examined whether the levels of 25 amino acids, including glutamate and glutamine, in the platelet-poor plasma of drug-naïve, male children with high-functioning autism (HFA would be altered compared with those of normal controls. METHODOLOGY/PRINCIPAL FINDINGS: Plasma levels of 25 amino acids in male children (N = 23 with HFA and normally developed healthy male controls (N = 22 were determined using high-performance liquid chromatography. Multiple testing was allowed for in the analyses. Compared with the normal control group, the HFA group had higher levels of plasma glutamate and lower levels of plasma glutamine. No significant group difference was found in the remaining 23 amino acids. The effect size (Cohen's d for glutamate and glutamine was large: 1.13 and 1.36, respectively. Using discriminant analysis with logistic regression, the two values of plasma glutamate and glutamine were shown to well-differentiate the HFA group from the control group; the rate of correct classification was 91%. CONCLUSIONS/SIGNIFICANCE: The present study suggests that plasma glutamate and glutamine levels can serve as a diagnostic tool for the early detection of autism, especially normal IQ autism. These findings indicate that glutamatergic abnormalities in the brain may be associated with the pathobiology of autism.

  13. Alteration of Plasma Brain Natriuretic Peptide Level After Acute Moderate Exercise in Professional Athletes

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    Homa Sheikhani


    Full Text Available Background: Cardiac fatigue or myocardial damage following exercise until complete exhaustion can increase blood levels of brain natriuretic peptide (BNP in athletes. Objectives: The aim of the present study was to investigate the effect of resistance and acute moderate aerobic exercise on alterations in BNP levels in professional athletes. Materials and Methods: Forty professional athletes who had at least 3 years of a championship background in track and field (aerobic group or body building (resistance group volunteered to participate in the present study. Track and field athletes (n = 20 were requested to run 8 km at 60% to 70% of maximum heart rate. Body building athletes (n = 20 performed a resistance training session of 5 exercises in 3 sets of 10 repetitions at 75% of 1 RM (bench press, seated row, leg extension, leg curl, and leg press. Before and immediately after the exercise, plasma BNP levels of both groups of athletes were measured by PATHFASTTM NT-proBNP assay, an immunochemiluminescent assay using two polyclonal antibodies in sandwich test format, on a PATHFASTTM automated analyzer. Results: Plasma BNP levels immediately following exercise increased significantly as compared with baseline values. Plasma BNP concentrations in the aerobic group were significantly higher than in the resistance group before and after exercise. Moreover, the increase in mean BNP concentrations in aerobic athletes was 7 times more than in resistance athletes. Conclusions: BNP levels in athlete who performed distance exercises increased significantly compared with resistance training. Possibly exercise program type, intensity of exercise, volume of exercise program, and field sport can be factors of changes in BNP levels

  14. Early life stress is a risk factor for excessive alcohol drinking and impulsivity in adults and is mediated via a CRF/GABA(A) mechanism. (United States)

    Gondré-Lewis, Marjorie C; Warnock, Kaitlin T; Wang, Hong; June, Harry L; Bell, Kimberly A; Rabe, Holger; Tiruveedhula, Veera Venkata Naga Phani Babu; Cook, James; Lüddens, Hartmut; Aurelian, Laure; June, Harry L


    Childhood stress and trauma are associated with substance use disorders in adulthood, but the neurological changes that confer increased vulnerability are largely unknown. In this study, maternal separation (MS) stress, restricted to the pre-weaning period, was used as a model to study mechanisms of protracted effects of childhood stress/traumatic experiences on binge drinking and impulsivity. Using an operant self-administration model of binge drinking and a delay discounting assay to measure impulsive-like behavior, we report that early life stress due to MS facilitated acquisition of binge drinking and impulsivity during adulthood in rats. Previous studies have shown heightened levels of corticotropin releasing factor (CRF) after MS, and here, we add that MS increased expression levels of GABA(A) α2 subunit in central stress circuits. To investigate the precise role of these circuits in regulating impulsivity and binge drinking, the CRF1 receptor antagonist antalarmin and the novel GABA(A) α2 subunit ligand 3-PBC were infused into the central amygdala (CeA) and medial prefrontal cortex (mPFC). Antalarmin and 3-PBC at each site markedly reduced impulsivity and produced profound reductions on binge-motivated alcohol drinking, without altering responding for sucrose. Furthermore, whole-cell patch-clamp studies showed that low concentrations of 3-PBC directly reversed the effect of relatively high concentrations of ethanol on α2β3γ2 GABA(A) receptors, by a benzodiazepine site-independent mechanism. Together, our data provide strong evidence that maternal separation, i.e. early life stress, is a risk factor for binge drinking, and is linked to impulsivity, another key risk factor for excessive alcohol drinking. We further show that pharmacological manipulation of CRF and GABA receptor signaling is effective to reverse binge drinking and impulsive-like behavior in MS rats. These results provide novel insights into the role of the brain stress systems in the

  15. Muscimol as an ionotropic GABA receptor agonist. (United States)

    Johnston, Graham A R


    Muscimol, a psychoactive isoxazole from Amanita muscaria and related mushrooms, has proved to be a remarkably selective agonist at ionotropic receptors for the inhibitory neurotransmitter GABA. This historic overview highlights the discovery and development of muscimol and related compounds as a GABA agonist by Danish and Australian neurochemists. Muscimol is widely used as a ligand to probe GABA receptors and was the lead compound in the development of a range of GABAergic agents including nipecotic acid, tiagabine, 4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol, (Gaboxadol(®)) and 4-PIOL.

  16. GABA and Topiramate Inhibit the Formation of Human Macrophage-Derived Foam Cells by Modulating Cholesterol-Metabolism-Associated Molecules

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    Ying Yang


    Full Text Available Aims: γ-aminobutyric acid (GABA, the principal inhibitory neurotransmitter, acts on GABA receptors to play an important role in the modulation of macrophage functions. The present study examined the effects of GABA and a GABA receptor agonist on modulating cholesterol-metabolism-associated molecules in human monocyte-derived macrophages (HMDMs. Methods: ORO stain, HPLC, qRT-PCR, Western blot and EMSA were carried out using HMDMs exposed to ox-LDL with or without GABAergic agents as the experimental model. Results: GABA and topiramate reduced the percentage of cholesterol ester in lipid-laden HMDMs by down-regulating SR-A, CD36 and LOX-1 expression and up-regulating ABCA1, ABCG1 and SR-BI expression in lipid-laden HMDMs. The production of TNF-a was decreased in GABA-and topiramate-treated lipid-laden HMDMs, and levels of interleukin (IL-6 did not change. The activation of two signaling pathways, p38MAPK and NF-γB, was repressed by GABA and topiramate in lipid-laden HMDMs. Conclusion: GABA and topiramate inhibit the formation of human macrophage-derived foam cells and may be a possibility for macrophage targeted therapy of atherosclerotic lesions.

  17. GABA Australis, some reflections on the history of GABA receptor research in Australia. (United States)

    Johnston, Graham A R


    Research on GABA receptors has a long history in Australia dating from 1958 with David Curtis and his colleagues in Canberra. This review traces many of the advances made in Australia guided by highly cited publications and some obscure ones. It covers the discovery of key chemicals with which to investigate GABA receptor function including bicuculline, muscimol, phaclofen, THIP and (+)-CAMP. Also described are findings relevant to the involvement of mutant GABA receptors in inherited epilepsy. The modulation of GABA receptors by a bewildering range of chemicals, especially by flavonoids and terpenoids, is discussed.

  18. Kinetic studies on the inhibition of GABA-T by gamma-vinyl GABA and taurine. (United States)

    Sulaiman, Saba A J; Suliman, Fakhr Eldin O; Barghouthi, Samira


    Gamma-aminobutyric acid transaminase (GABA-T, EC is a pyridoxal phosphate (PLP) dependent enzyme that catalyzes the degradation of gamma-aminobutyric acid. The kinetics of this reaction are studied in vitro, both in the absence, and in the presence of two inhibitors: gamma-vinyl GABA (4-aminohex-5-enoic acid), and a natural product, taurine (ethylamine-2-sulfonic acid). A kinetic model that describes the transamination process is proposed. GABA-T from Pseudomonas fluorescens is inhibited by gamma-vinyl GABA and taurine at concentrations of 51.0 and 78.5 mM. Both inhibitors show competitive inhibition behavior when GABA is the substrate and the inhibition constant (Ki) values for gamma-vinyl GABA and taurine were found to be 26 +/- 3 mM and 68 +/- 7 mM respectively. The transamination process of alpha-ketoglutarate was not affected by the presence of gamma-vinyl GABA, whereas, taurine was a noncompetitive inhibitor of GABA-T when alpha-ketoglutarate was the substrate. The inhibition dissociation constant (Kii) for this system was found to be 96 +/- 10 mM. The Michaelis-Menten constant (Km) in the absence of inhibition, was found to be 0.79 +/- 0.11 mM, and 0.47 +/- 0.10 mM for GABA and alpha-ketoglutarate respectively.

  19. Inhibition of GABA release by presynaptic ionotropic GABA receptors in hippocampal CA3. (United States)

    Axmacher, Nikolai; Draguhn, Andreas


    Vesicular transmitter release can be regulated by transmitter-gated ion channels at presynaptic axon terminals. The central inhibitory transmitter GABA acts on such presynaptic ionotropic receptors in various cells, including inhibitory interneurons. Here we report that GABA-mediated postsynaptic inhibitory currents in CA3 pyramidal cells of rat hippocampal slices are suppressed by agonists of GABAA receptors. The effect is present for both stimulus-induced and miniature IPSCs, indicating a reduction in the probability of vesicular release by presynaptic, action-potential-independent mechanisms. We conclude that the release of GABA from hippocampal CA3 interneurons is regulated by a negative feedback via presynaptic ionotropic GABA autoreceptors.

  20. Action of bicyclic isoxazole GABA analogues on GABA transporters and its relation to anticonvulsant activity

    DEFF Research Database (Denmark)

    Bolvig, T; Larsson, O M; Pickering, D S;


    The inhibitory action of bicyclic isoxazole gamma-aminobutyric acid (GABA) analogues and their 4,4-diphenyl-3-butenyl (DPB) substituted derivatives has been investigated in cortical neurones and astrocytes as well as in human embryonic kidney (HEK 293) cells transiently expressing either mouse GABA...... anticonvulsant activity, lack of proconvulsant activity and the ability of THPO to increase extracellular GABA concentration, indicate that these bicyclic isoxazole GABA analogues and their DPB derivatives may be useful lead structures in future search for new antiepileptic drugs....

  1. Below-ambient levels of UV induce chloroplast structural change and alter starch metabolism. (United States)

    Fagerberg, W R


    Electromagnetic radiation (EMR) in the 400-700 nm bandwidth of photosynthetically active radiation (PAR) has been established as an important source of energy for photosynthesis and environmental signals regulating many aspects of green-plant life. Above-ambient levels of UV-B radiation (290-320 nm) under high-PAR conditions have been shown to elicit responses in chloroplasts of Brassica napus similar to those of chloroplasts at low-PAR exposure (W. Fagerberg and J. Bornman, Physiol. Plant. 101: 833-844, 1997). The question arises as to whether UV at normal levels can also evoke similar responses. Here we provide evidence that even below-ambient levels of UV-B (1/28 ambient; Durham, N.H., U.S.A., 1200 hours, March) were capable of inducing an increase in thylakoid surface area relative to the chloroplast volume typical of a low-PAR response (shade response) in sunflowers. This response occurred even though leaves were concurrently exposed to PAR levels that normally induce a "sun" or high-PAR response in the absence of UV-B. Subambient levels of UV-B were also associated with a decrease in chloroplast and starch volume. Exposure to levels of UV-A 1/10 of ambient appeared to enhance the high-PAR response of the chloroplast, characterized by an increase in the amounts of stored starch, an increase in chloroplast volume density ratio values, and a decrease in thylakoid surface area density ratios relative to the high-light controls. These effects were opposite to those seen in UV-B-exposed tissue. In a general sense, subambient levels of UV-B evoked a response similar to that elicited by low-PAR irradiance, while subambient UV-A elicited responses similar to those typical of high-PAR irradiance. The fact that below-ambient levels of UV altered a normal chloroplast structural response to PAR provides evidence that UV may be an important environmental signal for plants.

  2. Amygdala-kindling induces a lasting reduction of GABA-immunoreactive neurons in a discrete area of the ipsilateral piriform cortex. (United States)

    Lehmann, H; Ebert, U; Löscher, W


    Several lines of evidence indicate a critical role of the piriform cortex (PC) in the kindling model of temporal lobe epilepsy, suggesting that the PC is part of an epileptic network that is pivotal in the genesis of kindling, facilitating, and intensifying the spread of seizures from a focus in amygdala, hippocampus, or other limbic brain regions to cortical and subcortical regions. Kindling of the amygdala has been shown to induce long-lasting changes in synaptic efficacy in the ipsilateral PC comparable to abnormalities seen in epileptic foci, but the neurochemical alterations possibly underlying these functional changes are not known. The possibility that the enhanced excitability of the PC in response to kindling is related to a reduction of GABAergic neurotransmission prompted us to examine if a lasting reduction in GABA-immunoreactive PC neurons is detectable after kindling of the basolateral amygdala (BLA) in rats. Furthermore, GABA immunoreactivity was determined in the BLA in order to investigate whether GABAergic neurons decrease in focal tissue, as previously suggested by neurochemical and immunocytochemical studies in amygdala-kindled rats. Three groups of age-matched rats were used: (1) a group of rats that was kindled via electrical stimulation by a bipolar electrode implanted in the right BLA, (2) a group of BLA-implanted but nonstimulated rats, and (3) a group of non-implanted, naive control rats. The kindled rats were sacrificed 40 days after the last fully kindled seizure. The two other groups of rats were sacrificed together with the kindled rats on the same days, and tissues from kindled and control rats were treated concurrently throughout the immunohistochemical analysis. GABA neurons were stained by a monoclonal antibody to GABA. Kindling of the BLA led to a pronounced decrease in the number of GABA immunoreactive neurons in the ipsi- and contralateral BLA at all section levels examined. In the PC, no significant differences between groups

  3. GABA maintains the proliferation of progenitors in the developing chick ciliary marginal zone and non-pigmented ciliary epithelium.

    Directory of Open Access Journals (Sweden)

    Henrik Ring

    Full Text Available GABA is more than the main inhibitory neurotransmitter found in the adult CNS. Several studies have shown that GABA regulates the proliferation of progenitor and stem cells. This work examined the effects of the GABA(A receptor system on the proliferation of retinal progenitors and non-pigmented ciliary epithelial (NPE cells. qRT-PCR and whole-cell patch-clamp electrophysiology were used to characterize the GABA(A receptor system. To quantify the effects on proliferation by GABA(A receptor agonists and antagonists, incorporation of thymidine analogues was used. The results showed that the NPE cells express functional extrasynaptic GABA(A receptors with tonic properties and that low concentration of GABA is required for a baseline level of proliferation. Antagonists of the GABA(A receptors decreased the proliferation of dissociated E12 NPE cells. Bicuculline also had effects on progenitor cell proliferation in intact E8 and E12 developing retina. The NPE cells had low levels of the Cl-transporter KCC2 compared to the mature retina, suggesting a depolarising role for the GABA(A receptors. Treatment with KCl, which is known to depolarise membranes, prevented some of the decreased proliferation caused by inhibition of the GABA(A receptors. This supported the depolarising role for the GABA(A receptors. Inhibition of L-type voltage-gated Ca(2+ channels (VGCCs reduced the proliferation in the same way as inhibition of the GABA(A receptors. Inhibition of the channels increased the expression of the cyclin-dependent kinase inhibitor p27(KIP1, along with the reduced proliferation. These results are consistent with that when the membrane potential indirectly regulates cell proliferation with hyperpolarisation of the membrane potential resulting in decreased cell division. The increased expression of p27(KIP1 after inhibition of either the GABA(A receptors or the L-type VGCCs suggests a link between the GABA(A receptors, membrane potential, and

  4. Resveratrol alters the lipid composition, metabolism and peroxide level in senescent rat hepatocytes. (United States)

    Momchilova, Albena; Petkova, Diana; Staneva, Galya; Markovska, Tania; Pankov, Roumen; Skrobanska, Ralica; Nikolova-Karakashian, Mariana; Koumanov, Kamen


    Investigations were performed on the influence of resveratrol on the lipid composition, metabolism, fatty acid and peroxide level in plasma membranes of hepatocytes, isolated from aged rats. Hepatocytes were chosen due to the central role of the liver in lipid metabolism and homeostasis. The obtained results showed that the level of sphingomyelin (SM) and phosphatidylserine (PS) was augmented in plasma membranes of resveratrol-treated senescent hepatocytes. The saturated/unsaturated fatty acids ratio of the two most abundant membrane phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), was decreased as a result of resveratrol treatment. The neutral sphingomyelinase was found to be responsible for the increase of SM and the decrease of ceramide in plasma membranes of resveratrol-treated senescent hepatocytes. Using labeled acetate as a precursor of lipid synthesis we demonstrated, that resveratrol treatment resulted in inhibition mainly of phospholipid synthesis, followed by fatty acids synthesis. Resveratrol induced reduction of specific membrane-associated markers of apoptosis such as localization of PS in the external plasma membrane monolayer and ceramide level. Finally, the content of lipid peroxides was investigated, because the unsaturated fatty acids, which were augmented as a result of resveratrol treatment, are an excellent target of oxidative attack. The results showed that the lipid peroxide level was significantly lower, ROS were slightly reduced and GSH was almost unchanged in resveratrol-treated hepatocytes. We suggest, that one possible biochemical mechanism, underlying the reported resveratrol-induced changes, is the partial inactivation of neutral sphingomyelinase, leading to increase of SM, the latter acting as a native membrane antioxidant. In conclusion, our studies indicate that resveratrol treatment induces beneficial alterations in the phospholipid and fatty acid composition, as well as in the ceramide and peroxide

  5. Prenatal Hyperandrogenization Induces Metabolic and Endocrine Alterations Which Depend on the Levels of Testosterone Exposure (United States)

    Amalfi, Sabrina; Velez, Leandro Martín; Heber, María Florencia; Vighi, Susana; Ferreira, Silvana Rocío; Orozco, Adriana Vega; Pignataro, Omar; Motta, Alicia Beatriz


    Prenatal hyperandrogenism is able to induce polycystic ovary syndrome (PCOS) in rats. The aim of the present study was to establish if the levels of prenatal testosterone may determine the extent of metabolic and endocrine alterations during the adult life. Pregnant Sprague Dawley rats were prenatally injected with either 2 or 5 mg free testosterone (groups T2 and T5 respectively) from day 16 to day 19 day of gestation. Female offspring from T2 and T5 displayed different phenotype of PCOS during adult life. Offspring from T2 showed hyperandrogenism, ovarian cysts and ovulatory cycles whereas those from T5 displayed hyperandrogenism, ovarian cysts and anovulatory cycles. Both group showed increased circulating glucose levels after the intraperitoneal glucose tolerance test (IPGTT; an evaluation of insulin resistance). IPGTT was higher in T5 rats and directly correlated with body weight at prepubertal age. However, the decrease in the body weight at prepubertal age was compensated during adult life. Although both groups showed enhanced ovarian steroidogenesis, it appears that the molecular mechanisms involved were different. The higher dose of testosterone enhanced the expression of both the protein that regulates cholesterol availability (the steroidogenic acute regulatory protein (StAR)) and the protein expression of the transcriptional factor: peroxisome proliferator-activated receptor gamma (PPAR gamma). Prenatal hyperandrogenization induced an anti-oxidant response that prevented a possible pro-oxidant status. The higher dose of testosterone induced a pro-inflammatory state in ovarian tissue mediated by increased levels of prostaglandin E (PG) and the protein expression of cyclooxygenase 2 (COX2, the limiting enzyme of PGs synthesis). In summary, our data show that the levels of testosterone prenatally injected modulate the uterine environment and that this, in turn, would be responsible for the endocrine and metabolic abnormalities and the phenotype of PCOS

  6. In Vivo Measurement of GABA Transmission in Healthy Subjects and Schizophrenia Patients (United States)

    Frankle, W. Gordon; Cho, Raymond Y.; Prasad, Konasale M.; Mason, N. Scott; Paris, Jennifer; Himes, Michael L.; Walker, Christopher; Lewis, David A.; Narendran, Rajesh


    Objective Postmortem studies in schizophrenia reveal alterations in gene products that regulate the release and extracellular persistence of GABA. However, results of in vivo studies of schizophrenia measuring total tissue GABA with magnetic resonance spectroscopy (MRS) have been inconsistent. Neither the postmortem nor the MRS studies directly address the physiological properties of GABA neurotransmission. The present study addresses this question through an innovative positron emission tomography (PET) paradigm. Method The binding of [11C]flumazenil, a benzodiazepine-specific PET radiotracer, was measured before and after administration of tiagabine (0.2 mg/kg of body weight), a GABA membrane transporter (GAT1) blocker, in 17 off-medication patients with schizophrenia and 22 healthy comparison subjects. Increased extracellular GABA, through GAT1 blockade, enhances the affinity of GABAA receptors for benzodiazepine ligands, detected as an increase in [11C]flumazenil tissue distribution volume (VT). Results [11C]Flumazenil VT was significantly increased across all cortical brain regions in the healthy comparison group but not in the schizophrenia group. This lack of effect was most prominent in the antipsychotic-naive schizophrenia group. In this subgroup, [11C]flumazenil ΔVT in the medial temporal lobe was correlated with positive symptoms, and baseline [11C] flumazenil VT in the medial temporal lobe was negatively correlated with visual learning. In the healthy comparison group but not the schizophrenia group, [11C]flumazenil ΔVT was positively associated with gamma-band oscillation power. Conclusions This study demonstrates, for the first time, an in vivo impairment in GABA transmission in schizophrenia, most prominent in antipsychotic-naive individuals. The impairment in GABA transmission appears to be linked to clinical symptoms, disturbances in cortical oscillations, and cognition. PMID:26133962

  7. Elevated CO{sub 2} levels and herbivore damage alter host plant preferences

    Energy Technology Data Exchange (ETDEWEB)

    Agrell, J. [Lund Univ., Dept. of Animal Ecology, Lund (Sweden); Anderson, Peter, Swedish Univ. of Agricultural Sciences, Dept. of Crop Sciences, Alnarp (SE)); Oleszek, W.; Stochmal, Anna [Inst. of Soil Science and Plant Cultivation, Dept. of Biochemistry, Pulawy (Poland); Agrell, Cecilia [Lund Univ., Dept. of Chemical Ecology and Ecotoxicology, Lund (Sweden)


    Interactions between the moth Spodoptera littoralis and two of its host plants, alfalfa (Medicago sativa) and cotton (Gossypium hirsutum) were examined, using plants grown under ambient (350 ppm) and elevated (700 ppm) CO{sub 2} conditions. To determine strength and effects of herbivore-induced responses assays were performed with both undamaged (control) and herbivore damaged plants. CO{sub 2} and damage effects on larval host plant preferences were determined through dual-choice bioassays. In addition, larvae were reared from hatching to pupation on experimental foliage to examine effects on larval growth and development. When undamaged plants were used S. littoralis larvae in consumed more cotton than alfalfa, and CO{sub 2} enrichment caused a reduction in the preference for cotton. With damaged plants larvae consumed equal amounts of the two plant species (ambient CO{sub 2} conditions), but CO{sub 2} enrichment strongly shifted preferences towards cotton, which was then consumed three times more than alfalfa. Complementary assays showed that elevated CO{sub 2} levels had no effect on the herbivore-induced responses of cotton, whereas those of alfalfa were significantly increased. Larval growth was highest for larvae fed undamaged cotton irrespectively of CO{sub 2} level, and lowest for larvae on damaged alfalfa from the high CO{sub 2} treatment. Development time increased on damaged cotton irrespectively of CO{sub 2} treatment, and on damaged alfalfa in the elevated CO{sub 2} treatment. (au) These results demonstrate that elevated CO2 levels can cause insect herbivores to alter host plant preferences, and that effects on herbivore-induced responses may be a key mechanism behind these processes. Furthermore, since the insects were shown to avoid foliage that reduced their physiological performance, our data suggest that behavioural host plant shifts result in partial escape from negative consequences of feeding on high CO2 foliage. Thus, CO2 enrichment can alter

  8. Smoking, alcoholism and genetic polymorphisms alter CYP2B6 levels in human brain. (United States)

    Miksys, Sharon; Lerman, Caryn; Shields, Peter G; Mash, Deborah C; Tyndale, Rachel F


    CYP2B6 metabolizes drugs such as nicotine and bupropion, and many toxins and carcinogens. Nicotine induces CYP2B1 in rat brain and in humans polymorphic variation in CYP2B6 affects smoking cessation rates. The aim of this study was to compare CYP2B6 expression in brains of human smokers and non-smokers and alcoholics and non-alcoholics (n=26). CYP2B6 expression was brain region-specific, and was observed in both neurons and astrocytes. CYP2B6 levels were higher in brains of smokers and alcoholics, particularly in cerebellar Purkinje cells and hippocampal pyramidal neurons, cells known to be damaged in alcoholics. Significantly more (penzyme levels, stability and activity. Preliminary genotyping of this small sample (n=24) suggested that individuals with the CC genotype had higher brain CYP2B6 than those with the CT or TT genotype. Higher brain CYP2B6 activity in smokers and alcoholics may cause altered sensitivity to centrally acting drugs, increased susceptibility to neurotoxins and carcinogenic xenobiotics and contribute to central tolerance to nicotine.

  9. Fetal rat metabonome alteration by prenatal caffeine ingestion probably due to the increased circulatory glucocorticoid level and altered peripheral glucose and lipid metabolic pathways

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yansong [Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan University, Wuhan, 430071 (China); Xu, Dan [Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan University, Wuhan, 430071 (China); Research Center of Food and Drug Evaluation, Wuhan University, Wuhan, 430071 (China); Feng, Jianghua, E-mail: [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071 (China); Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, 361005 (China); Kou, Hao; Liang, Gai [Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan University, Wuhan, 430071 (China); Yu, Hong; He, Xiaohua; Zhang, Baifang; Chen, Liaobin [Research Center of Food and Drug Evaluation, Wuhan University, Wuhan, 430071 (China); Magdalou, Jacques [UMR 7561 CNRS-Nancy Université, Faculté de Médicine, Vandoeuvre-lès-Nancy (France); Wang, Hui, E-mail: [Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan University, Wuhan, 430071 (China); Research Center of Food and Drug Evaluation, Wuhan University, Wuhan, 430071 (China)


    The aims of this study were to clarify the metabonome alteration in fetal rats after prenatal caffeine ingestion and to explore the underlying mechanism pertaining to the increased fetal circulatory glucocorticoid (GC). Pregnant Wistar rats were daily intragastrically administered with different doses of caffeine (0, 20, 60 and 180 mg/kg) from gestational days (GD) 11 to 20. Metabonome of fetal plasma and amniotic fluid on GD20 were analyzed by {sup 1}H nuclear magnetic resonance-based metabonomics. Gene and protein expressions involved in the GC metabolism, glucose and lipid metabolic pathways in fetal liver and gastrocnemius were measured by real-time RT-PCR and immunohistochemistry. Fetal plasma metabonome were significantly altered by caffeine, which presents as the elevated α- and β‐glucose, reduced multiple lipid contents, varied apolipoprotein contents and increased levels of a number of amino acids. The metabonome of amniotic fluids showed a similar change as that in fetal plasma. Furthermore, the expressions of 11β-hydroxysteroid dehydrogenase 2 (11β-HSD-2) were decreased, while the level of blood GC and the expressions of 11β-HSD-1 and glucocorticoid receptor (GR) were increased in fetal liver and gastrocnemius. Meanwhile, the expressions of insulin-like growth factor 1 (IGF-1), IGF-1 receptor and insulin receptor were decreased, while the expressions of adiponectin receptor 2, leptin receptors and AMP-activated protein kinase α2 were increased after caffeine treatment. Prenatal caffeine ingestion characteristically change the fetal metabonome, which is probably attributed to the alterations of glucose and lipid metabolic pathways induced by increased circulatory GC, activated GC metabolism and enhanced GR expression in peripheral metabolic tissues. -- Highlights: ► Prenatal caffeine ingestion altered the metabonome of IUGR fetal rats. ► Caffeine altered the glucose and lipid metabolic pathways of IUGR fetal rats. ► Prenatal caffeine

  10. Behavioral deficit and decreased GABA receptor functional regulation in the hippocampus of epileptic rats: effect of Bacopa monnieri. (United States)

    Mathew, Jobin; Gangadharan, Gireesh; Kuruvilla, Korah P; Paulose, C S


    In the present study, alterations of the General GABA and GABA(A) receptors in the hippocampus of pilocarpine-induced temporal lobe epileptic rats and the therapeutic application of Bacopa monnieri and its active component Bacoside-A were investigated. Bacopa monnieri (Linn.) is a herbaceous plant belonging to the family Scrophulariaceae. Hippocampus is the major region of the brain belonging to the limbic system and plays an important role in epileptogenesis, memory and learning. Scatchard analysis of [³H]GABA and [³H]bicuculline in the hippocampus of the epileptic rat showed significant decrease in B(max) (P Bacoside-A treatment reverses all these changes near to control. Our results suggest that decreased GABA receptors in the hippocampus have an important role in epilepsy associated behavioral deficit, Bacopa monnieri and Bacoside-A have clinical significance in the management of epilepsy.

  11. Changes of GABA A Receptor α1 Subunit mRNA and [3H] Flunirazepam Binding in Animal Model of Status Epileptic Rats

    Institute of Scientific and Technical Information of China (English)

    Qinchi Lu


    OBJECTIVE: In the present study, we determinded whether status epilepticus or prolonged limbic seizures ( induced by pilocarpine) altered GABA A receptor αl subunit gene expression m the hippocanpus. BACKGROUND: A decrease in GABAergic inhibition during epileptogenesis plays an imprortant role in the development of persistent hyperexcitability observed during chronic epilepsy. METHODS: Stares epilepticus was reduced in male adult rats by a single i.p. injection ofpilocarpine (320-340 mg/kg). Rats that survived status epilepticus ( definded as continous seizure activity in the EcoG for at least 40 min) for 1 h and 2 h were sacrificed for GABA A receptor gene expression and binding assay. In situ hybridization was used to measure regional mRNA levels, and [3H] flunirazepam used to label the benzodiazepine binding sites. RESULTS: We found that 2h after the onset of seizure, GABA A receptor α1 m RNA decresed significarntly in the CA1 and CA3 fields of hippocampus. No significant change in ctl mRNA was observed in the dentate gyrus. However, [3H] flunirazepam binding decreased uniformly in CA l, CA3 and dentate gyrus 2h after status epfileptius. 1 h ofcontinuous seizures did not produce any significant change in either αl mRNA or [3H] flunirazepam birding in any of the hippocampal regions studied. Cresyl violet staining of the brain hippocampus areas lh or 2h after the seizure-onset. DISCUSSION: The above changes make the brain more susceptible for the development of chronic epilepsy. CONCLUSION: These results suggest that status epilepticus-induced decreased in GABA A recepor αl gene expression and [3H] flunirazepam binding in the hippocampus.

  12. Effects of Altered Levels of Extracellular Superoxide Dismutase and Irradiation on Hippocampal Neurogenesis in Female Mice

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Yani [Department of Neurology and Neurological Sciences, Stanford University, Stanford, California (United States); Leu, David [Department of Neurology and Neurological Sciences, Stanford University, Stanford, California (United States); Palo Alto Institute of Research and Education, Palo Alto, California (United States); Chui, Jennifer [Department of Neurology and Neurological Sciences, Stanford University, Stanford, California (United States); Fike, John R. [Departments of Neurosurgery and Radiation Oncology, University of California, San Francisco, California (United States); Huang, Ting-Ting, E-mail: [Department of Neurology and Neurological Sciences, Stanford University, Stanford, California (United States); VA Palo Alto Health Care System, Palo Alto, California (United States)


    Purpose: Altered levels of extracellular superoxide dismutase (EC-SOD) and cranial irradiation have been shown to affect hippocampal neurogenesis. However, previous studies were only conducted in male mice, and it was not clear if there was a difference between males and females. Therefore, female mice were studied and the results compared with those generated in male mice from an earlier study. Methods and Materials: Female wild-type, EC-SOD-null (KO), and EC-SOD bigenic mice with neuronal-specific expression of EC-SOD (OE) were subjected to a single dose of 5-Gy gamma rays to the head at 8 weeks of age. Progenitor cell proliferation, differentiation, and long-term survival of newborn neurons were determined. Results: Similar to results from male mice, EC-SOD deficiency and irradiation both resulted in significant reductions in mature newborn neurons in female mice. EC-SOD deficiency reduced long-term survival of newborn neurons whereas irradiation reduced progenitor cell proliferation. Overexpression of EC-SOD corrected the negative impacts from EC-SOD deficiency and irradiation and normalized the production of newborn neurons in OE mice. Expression of neurotrophic factors brain-derived neurotrophic factor and neurotrophin-3 were significantly reduced by irradiation in wild-type mice, but the levels were not changed in KO and OE mice even though both cohorts started out with a lower baseline level. Conclusion: In terms of hippocampal neurogenesis, EC-SOD deficiency and irradiation have the same overall effects in males and females at the age the studies were conducted.

  13. Sleep duration varies as a function of glutamate and GABA in rat pontine reticular formation. (United States)

    Watson, Christopher J; Lydic, Ralph; Baghdoyan, Helen A


    The oral part of the pontine reticular formation (PnO) is a component of the ascending reticular activating system and plays a role in the regulation of sleep and wakefulness. The PnO receives glutamatergic and GABAergic projections from many brain regions that regulate behavioral state. Indirect, pharmacological evidence has suggested that glutamatergic and GABAergic signaling within the PnO alters traits that characterize wakefulness and sleep. No previous studies have simultaneously measured endogenous glutamate and GABA from rat PnO in relation to sleep and wakefulness. The present study utilized in vivo microdialysis coupled on-line to capillary electrophoresis with laser-induced fluorescence to test the hypothesis that concentrations of glutamate and GABA in the PnO vary across the sleep/wake cycle. Concentrations of glutamate and GABA were significantly higher during wakefulness than during non-rapid eye movement sleep and rapid eye movement sleep. Regression analysis revealed that decreases in glutamate and GABA accounted for a significant portion of the variance in the duration of non-rapid eye movement sleep and rapid eye movement sleep episodes. These data provide novel support for the hypothesis that endogenous glutamate and GABA in the PnO contribute to the regulation of sleep duration.

  14. The anti-convulsant stiripentol acts directly on the GABA(A) receptor as a positive allosteric modulator. (United States)

    Fisher, Janet L


    Stiripentol (STP) has been used as co-therapy for treatment of epilepsy for many years. Its mechanism of action has long been considered to be indirect, as it inhibits the enzymes responsible for metabolism of other anti-convulsant agents. However, a recent report suggested that STP might also act at the neuronal level, increasing inhibitory GABAergic neurotransmission. We examined the effect of STP on the functional properties of recombinant GABA(A) receptors (GABARs) and found that it was a positive allosteric modulator of these ion channels. Its activity showed some dependence on subunit composition, with greater potentiation of alpha3-containing receptors and reduced potentiation when the beta1 or epsilon subunits were present. STP caused a leftward shift in the GABA concentration-response relationship, but did not increase the peak response of the receptors to a maximal GABA concentration. Although STP shares some functional characteristics with the neurosteroids, its activity was not inhibited by a neurosteroid site antagonist and was unaffected by a mutation in the alpha3 subunit that reduced positive modulation by neurosteroids. The differential effect of STP on beta1- and beta2/beta3-containing receptors was not altered by mutations within the second transmembrane domain that affect modulation by loreclezole. These findings suggest that STP acts as a direct allosteric modulator of the GABAR at a site distinct from many commonly used anti-convulsant, sedative and anxiolytic drugs. Its higher activity at alpha3-containing receptors as well as its activity at delta-containing receptors may provide a unique opportunity to target selected populations of GABARs.

  15. GabaB receptors activation in the NTS blocks the glycemic responses induced by carotid body receptor stimulation. (United States)

    Lemus, Mónica; Montero, Sergio; Cadenas, José Luis; Lara, José Jesús; Tejeda-Chávez, Héctor Rafael; Alvarez-Buylla, Ramón; de Alvarez-Buylla, Elena Roces


    The carotid body receptors participate in glucose regulation sensing glucose levels in blood entering the cephalic circulation. The carotid body receptors information, is initially processed within the nucleus tractus solitarius (NTS) and elicits changes in circulating glucose and brain glucose uptake. Previous work has shown that gamma-aminobutyric acid (GABA) in NTS modulates respiratory reflexes, but the role of GABA within NTS in glucose regulation remains unknown. Here we show that GABA(B) receptor agonist (baclofen) or antagonists (phaclofen and CGP55845A) locally injected into NTS modified arterial glucose levels and brain glucose retention. Control injections outside NTS did not elicit these responses. In contrast, GABA(A) agonist and antagonist (muscimol or bicuculline) produced no significant changes in blood glucose levels. When these GABAergic drugs were applied before carotid body receptors stimulation, again, only GABA(B) agonist or antagonist significantly affected glycemic responses; baclofen microinjection significantly reduced the hyperglycemic response and brain glucose retention observed after carotid body receptors stimulation, while phaclofen produced the opposite effect, increasing significantly hyperglycemia and brain glucose retention. These results indicate that activation of GABA(B), but not GABA(A), receptors in the NTS modulates the glycemic responses after anoxic stimulation of the carotid body receptors, and suggest the presence of a tonic inhibitory mechanism in the NTS to avoid hyperglycemia.

  16. Excitatory action of GABA on immature neurons is not due to absence of ketone bodies metabolites or other energy substrates. (United States)

    Ben-Ari, Yehezkel; Tyzio, Roman; Nehlig, Astrid


    Brain slices incubated with glucose have provided most of our knowledge on cellular, synaptic, and network driven mechanisms. It has been recently suggested that γ-aminobutyric acid (GABA) excites neonatal neurons in conventional glucose-perfused slices but not when ketone bodies metabolites, pyruvate, and/or lactate are added, suggesting that the excitatory actions of GABA are due to energy deprivation when glucose is the sole energy source. In this article, we review the vast number of studies that show that slices are not energy deprived in glucose-containing medium, and that addition of other energy substrates at physiologic concentrations does not alter the excitatory actions of GABA on neonatal neurons. In contrast, lactate, like other weak acids, can produce an intracellular acidification that will cause a reduction of intracellular chloride and a shift of GABA actions. The effects of high concentrations of lactate, and particularly of pyruvate (4-5 mm), as used are relevant primarily to pathologic conditions; these concentrations not being found in the brain in normal "control" conditions. Slices in glucose-containing medium may not be ideal, but additional energy substrates neither correspond to physiologic conditions nor alter GABA actions. In keeping with extensive observations in a wide range of animal species and brain structures, GABA depolarizes immature neurons and the reduction of the intracellular concentration of chloride ([Cl(-)](i)) is a basic property of brain maturation that has been preserved throughout evolution. In addition, this developmental sequence has important clinical implications, notably concerning the higher incidence of seizures early in life and their long-lasting deleterious sequels. Immature neurons have difficulties exporting chloride that accumulates during seizures, leading to permanent increase of [Cl(-)](i) that converts the inhibitory actions of GABA to excitatory and hampers the efficacy of GABA-acting antiepileptic

  17. GABA-agonists induce the formation of low-affinity GABA-receptors on cultured cerebellar granule cells via preexisting high affinity GABA receptors

    DEFF Research Database (Denmark)

    Belhage, B; Meier, E; Schousboe, A


    The kinetics of specific GABA-binding to membranes isolated from cerebellar granule cells, cultured for 12 days from dissociated cerebella of 7-day-old rats was studied using [3H]GABA as the ligand. The granule cells were cultured in the presence of the specific GABA receptor agonist 4, 5, 6, 7-t...

  18. Differential effects of phosphonic analogues of GABA on GABA(B) autoreceptors in rat neocortical slices. (United States)

    Ong, J; Marino, V; Parker, D A; Kerr, D I


    The effects of five phosphonic derivatives of GABA on the release of [3H]-GABA from rat neocortical slices, preloaded with [3H]-GABA, were investigated. Phaclofen and 4-aminobutylphosphonic acid (4-ABPA) increased the overflow of [3H] evoked by electrical stimulation (2 Hz) in a concentration-dependent manner, with similar potencies (phaclofen EC50=0.3 mmol/l, 4-ABPA EC50=0.4 mmol/l). At 3 mmol/l, phaclofen increased the release of [3H]-GABA by 82.6+/-8.6%, and 4-ABPA increased the release by 81.3+/-9.0%. 2-Amino-ethylphosphonic acid (2-AEPA) increased the overflow of [3H] by 46.8+/-10.9% at the highest concentration tested (3 mmol/l). In contrast, the lower phosphonic homologue 3-aminopropylphosphonic acid (3-APPA), and 2-amino-2-(p-chlorophenyl)-ethylphosphonic acid (2-CPEPA), a baclofen analogue, did not modify the stimulated overflow. These results suggest that phaclofen, 4-ABPA and 2-AEPA are antagonists at GABA(B) autoreceptors, the latter being the weakest antagonist, whilst neither 3-APPA nor 2-CPEPA are active at these receptors. Since phaclofen, 4-ABPA and 2-CPEPA are antagonists and 3-APPA a partial agonist/antagonist on GABA(B) heteroreceptors, the lack of effect of 3-APPA and 2-CPEPA on [3H]-GABA release in this study suggests that GABA(B) autoreceptors may be pharmacologically distinct from the heteroreceptors.

  19. GABA(A) receptor- and GABA transporter polymorphisms and risk for essential tremor

    DEFF Research Database (Denmark)

    Thier, S; Kuhlenbäumer, G; Lorenz, D


    Background:  Clinical features and animal models of essential tremor (ET) suggest gamma-aminobutyric acid A receptor (GABA(A) R) subunits and GABA transporters as putative candidate genes. Methods:  A total of 503 ET cases and 818 controls were investigated for an association between polymorphisms...

  20. Effect of THIP and SL 76002, two clinically experimented GABA-mimetic compounds, on anterior pituitary GABA receptors and prolactin secretion in the rat

    Energy Technology Data Exchange (ETDEWEB)

    Apud, J.A.; Masotto, C.; Racagni, G.


    In the present study, the ability of three direct GABA agonists, muscimol, THIP and SL 76002 to displace /sup 3/H-GABA binding from anterior pituitary and medio-basal hypothalamus membranes was evaluated. Further, the effect of both THIP and SL 76002 on baseline prolactin levels or after stimulation of hormone release with haloperidol has been also studied. Either muscimol, THIP or SL 76002 have shown to posses 7-, 7- and 3-fold higher affinity, respectively, for the central nervous system than for the anterior pituitary /sup 3/H-GABA binding sites. Moreover, THIP and SL 76002 have demonstrated to be respectively, 25- and 1000- fold less potent than muscimol in inhibiting /sup 3/H- GABA binding at the level of the anterior pituitary and about 25- and 2700-fold less potent at the level of the medio-basal hypothalamus. Under basal conditions, either THIP or SL 76002 were ineffective to reduce prolactin release. However, after stimulation of prolactin secretion through blockade of the dopaminergic neurotransmission with haloperidol (0.1 mg/kg), both THIP (10 mg/kg) and SL 76002 (200 mg/kg) significantly counteracted the neuroleptic-induced prolactin rise with a potency which is in line with their ability to inhibit /sup 3/H-GABA binding in the anterior pituitary. The present results indicate that both compounds inhibit prolactin release under specific experimental situations probably through a GABAergic mechanism. In view of the endocrine effects of these GABA-mimetic compounds, the possibility arises for an application of these type of drugs in clinical neuroendocrinology. 35 references, 3 figures, 2 tables.

  1. GABA(B2) is essential for g-protein coupling of the GABA(B) receptor heterodimer. (United States)

    Robbins, M J; Calver, A R; Filippov, A K; Hirst, W D; Russell, R B; Wood, M D; Nasir, S; Couve, A; Brown, D A; Moss, S J; Pangalos, M N


    GABA(B) receptors are unique among G-protein-coupled receptors (GPCRs) in their requirement for heterodimerization between two homologous subunits, GABA(B1) and GABA(B2), for functional expression. Whereas GABA(B1) is capable of binding receptor agonists and antagonists, the role of each GABA(B) subunit in receptor signaling is unknown. Here we identified amino acid residues within the second intracellular domain of GABA(B2) that are critical for the coupling of GABA(B) receptor heterodimers to their downstream effector systems. Our results provide strong evidence for a functional role of the GABA(B2) subunit in G-protein coupling of the GABA(B) receptor heterodimer. In addition, they provide evidence for a novel "sequential" GPCR signaling mechanism in which ligand binding to one heterodimer subunit can induce signal transduction through the second partner of a heteromeric complex.

  2. Mutations in γ-aminobutyric acid (GABA) transaminase genes in plants or Pseudomonas syringae reduce bacterial virulence. (United States)

    Park, Duck Hwan; Mirabella, Rossana; Bronstein, Philip A; Preston, Gail M; Haring, Michel A; Lim, Chun Keun; Collmer, Alan; Schuurink, Robert C


    Pseudomonas syringae pv. tomato DC3000 is a bacterial pathogen of Arabidopsis and tomato that grows in the apoplast. The non-protein amino acid γ-amino butyric acid (GABA) is produced by Arabidopsis and tomato and is the most abundant amino acid in the apoplastic fluid of tomato. The DC3000 genome harbors three genes annotated as gabT GABA transaminases. A DC3000 mutant lacking all three gabT genes was constructed and found to be unable to utilize GABA as a sole carbon and nitrogen source. In complete minimal media supplemented with GABA, the mutant grew less well than wild-type DC3000 and showed strongly reduced expression of hrpL and avrPto, which encode an alternative sigma factor and effector, respectively, associated with the type III secretion system. The growth of the gabT triple mutant was weakly reduced in Arabidopsis ecotype Landberg erecta (Ler) and strongly reduced in the Ler pop2-1 GABA transaminase-deficient mutant that accumulates higher levels of GABA. Much of the ability to grow on GABA-amended minimal media or in Arabidopsis pop2-1 leaves could be restored to the gabT triple mutant by expression in trans of just gabT2. The ability of DC3000 to elicit the hypersensitive response (HR) in tobacco leaves is dependent upon deployment of the type III secretion system, and the gabT triple mutant was less able than wild-type DC3000 to elicit this HR when bacteria were infiltrated along with GABA at levels of 1 mm or more. GABA may have multiple effects on P. syringae-plant interactions, with elevated levels increasing disease resistance.

  3. Genetic KCa3.1-deficiency produces locomotor hyperactivity and alterations in cerebral monoamine levels.

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    Kate Lykke Lambertsen

    Full Text Available BACKGROUND: The calmodulin/calcium-activated K(+ channel KCa3.1 is expressed in red and white blood cells, epithelia and endothelia, and possibly central and peripheral neurons. However, our knowledge about its contribution to neurological functions and behavior is incomplete. Here, we investigated whether genetic deficiency or pharmacological activation of KCa3.1 change behavior and cerebral monoamine levels in mice. METHODOLOGY/PRINCIPAL FINDINGS: In the open field test, KCa3.1-deficiency increased horizontal activity, as KCa3.1(-/- mice travelled longer distances (≈145% of KCa3.1(+/+ and at higher speed (≈1.5-fold of KCa3.1(+/+. Working memory in the Y-maze was reduced by KCa3.1-deficiency. Motor coordination on the rotarod and neuromuscular functions were unchanged. In KCa3.1(-/- mice, HPLC analysis revealed that turn-over rates of serotonin were reduced in frontal cortex, striatum and brain stem, while noradrenalin turn-over rates were increased in the frontal cortex. Dopamine turn-over rates were unaltered. Plasma catecholamine and corticosterone levels were unaltered. Intraperitoneal injections of 10 mg/kg of the KCa3.1/KCa2-activator SKA-31 reduced rearing and turning behavior in KCa3.1(+/+ but not in KCa3.1(-/- mice, while 30 mg/kg SKA-31 caused strong sedation in 50% of the animals of either genotypes. KCa3.1(-/- mice were hyperactive (≈+60% in their home cage and SKA-31-administration reduced nocturnal physical activity in KCa3.1(+/+ but not in KCa3.1(-/- mice. CONCLUSIONS/SIGNIFICANCE: KCa3.1-deficiency causes locomotor hyperactivity and altered monoamine levels in selected brain regions, suggesting a so far unknown functional link of KCa3.1 channels to behavior and monoaminergic neurotransmission in mice. The tranquilizing effects of low-dose SKA-31 raise the possibility to use KCa3.1/KCa2 channels as novel pharmacological targets for the treatment of neuropsychiatric hyperactivity disorders.

  4. Altered Carbon Isotope Discrimination of C3 Plants Under Very High pCO2 Levels (United States)

    Panetta, R. J.; Schubert, B.; Jahren, H.


    Various modeling and proxy-based reconstructions of atmospheric pCO2 levels for the last 120 Ma have estimated RCO2 as high as 12x for the Early Cretaceous, generally decreasing into the Cenozoic, and decreasing further into the Quaternary. Multiple ecological studies to assess the effect of elevated CO2 on plant biomass and δ13C value have been spurred on by recent increases in greenhouse gases, however these studies typically grow plants under only slightly elevated CO2 levels (i.e., the twenty foremost studies published since 1990 involved 550 to 750 ppm pCO2, which equals RCO2 = 1.4 to 1.9x). In order to recreate the highest pCO2 environments of the last 120 Ma, we grew radish (Raphanus sativus L.) in growth chambers that maintained controlled environmental conditions and pCO2 levels ranging from ~5 to 11x that of today’s atmosphere (1791 to 4200 ppm); upon harvest we measured total biomass and stable carbon isotope ratio (δ13Cplant) in both above and below ground plant tissue. Unlike the 1:1 relationship between stable isotopes of atmospheric CO2 (δ13Catm) and δ13Cplant observed at lower pCO2 levels (i.e., RCO2 = 1x to 3x; Jahren et al., 2008), the δ13Cplant of biomass grown at more elevated RCO2 was dependent upon δ13Catm according to the linear relationship: δ13Cplant = 1.9(δ13Cplant) - 12.2 ‰ (r2 = 0.71). Concomitantly, we see a highly significant (p sativus L. from -27.0 to -28.0 ‰ at RCO2 = 5x to 11x, respectively. We will discuss possible mechanisms for changing isotope discrimination at very high pCO2 levels that may not be operative at lower concentrations. For example, we noted a striking reduction in the variability of biomass between plants grown at the same (very high) level of pCO2. This variability (calculated as the standard deviation of the log-transformed biomass data after Poorter and Garnier, 1996) decreased by 37 % (above-ground) and 48 % (below-ground) for plants grown at RCO2 > 5x compared to plants grown at RCO2 = 1x to 3x


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    Full Text Available BACKGROUND HIV patients receiving highly active Anti-Retroviral Therapy (HAART usually suffer from side effects like hepatitis, neurological problems, abnormal fat distribution etc. Among these, the most physical, mental and cosmetically disturbing side effect is adipose tissue alterations (ATA, also called as lipodystrophy, which is abnormal fat deposition (Lipohypertrophy and/or fat atrophy (Lipoatrophy. AIM Several studies have shown dyslipidemia in patients on HAART, but there are very few studies on the lipid profile changes in patients on ART with ATA. Hence a study was conducted to assess the serum lipid profile and transaminases activity in patients on ART with ATA and also to evaluate whether lipid profile parameters can predict ATA changes in HIV patients on HAART. METHOD Randomly selected HIV positive patients, who were attending ART centre, were included in the study. Twenty five of these patients in whom HAART was yet to be started were considered as Control group, 25 patients on HAART for more than 12 months but without ATA as ART group and 23 patients on HAART with ATA as ATA group. Lipid profile and serum transaminases in all the groups were assayed by standard methods. RESULTS Serum cholesterol and LDL were significantly increased in ART group and ATA group when compared to control group, but there was no significant difference in lipid profile parameters between ART group and ATA group. Serum AST and ALT levels were significantly increased (p<0.02 in ATA group when compared to ART group. Buffalo hump was seen only in females in our study. Lipoatrophy (facial and limbs and central obesity was seen in males. CONCLUSION There was no significant change in lipid profile parameters in ATA group when compared with ART group. Hence lipid profile parameters are not good predictors of ATA changes in HIV patients on HAART. Significant increase in transaminase levels suggests increased hepatotoxity in ATA patients due to HAART drugs. There

  6. HSF1 transcriptional activity mediates alcohol induction of Vamp2 expression and GABA release

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    Florence P. Varodayan


    Full Text Available Many central synapses are highly sensitive to alcohol, and it is now accepted that short-term alterations in synaptic function may lead to longer term changes in circuit function. The regulation of postsynaptic receptors by alcohol has been well studied, but the mechanisms underlying the effects of alcohol on the presynaptic terminal are relatively unexplored. To identify a pathway by which alcohol regulates neurotransmitter release, we recently investigated the mechanism by which ethanol induces the Vamp2 gene, but not Vamp1, in mouse primary cortical cultures. These two genes encode isoforms of synaptobrevin, a vesicular soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE protein required for synaptic vesicle fusion. We found that alcohol activates the transcription factor heat shock factor 1 (HSF1 to induce Vamp2 gene expression, while Vamp1 mRNA levels remain unaffected. As the Vamp2 gene encodes a SNARE protein, we then investigated whether ethanol exposure and HSF1 transcriptional activity alter neurotransmitter release using electrophysiology. We found that alcohol increased the frequency of γ-aminobutyric acid (GABA-mediated miniature IPSCs via HSF1, but had no effect on mEPSCs. Overall, these data indicate that alcohol induces HSF1 transcriptional activity to trigger a specific coordinated adaptation in GABAergic presynaptic terminals. This mechanism could explain some of the changes in synaptic function that occur soon after alcohol exposure, and may underlie some of the more enduring effects of chronic alcohol intake on local circuit function.

  7. An excitatory GABA loop operating in vivo

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    Guadalupe eAstorga


    Full Text Available While it has been proposed that the conventional inhibitory neurotransmitter GABA can be excitatory in the mammalian brain, much remains to be learned concerning the circumstances and the cellular mechanisms governing potential excitatory GABA action. Using a combination of optogenetics and two-photon calcium imaging in vivo, we find that activation of chloride-permeable GABAA receptors in parallel fibers of the cerebellar molecular layer of adult mice causes parallel fiber excitation. Stimulation of parallel fibers at submaximal stimulus intensities leads to GABA release from molecular layer interneurons, thus creating a positive feedback loop that enhances excitation near the center of an activated parallel fiber bundle. Our results imply that elevated chloride concentration can occur in specific intracellular compartments of mature mammalian neurons and suggest an excitatory role for GABAA receptors in the cerebellar cortex of adult mice.

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

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    Sivan Subburaju

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

  9. VTA GABA neurons modulate specific learning behaviours through the control of dopamine and cholinergic systems

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    Meaghan C Creed


    Full Text Available The mesolimbic reward system is primarily comprised of the ventral tegmental area (VTA and the nucleus accumbens (NAc as well as their afferent and efferent connections. This circuitry is essential for learning about stimuli associated with motivationally-relevant outcomes. Moreover, addictive drugs affect and remodel this system, which may underlie their addictive properties. In addition to DA neurons, the VTA also contains approximately 30% ɣ-aminobutyric acid (GABA neurons. The task of signalling both rewarding and aversive events from the VTA to the NAc has mostly been ascribed to DA neurons and the role of GABA neurons has been largely neglected until recently. GABA neurons provide local inhibition of DA neurons and also long-range inhibition of projection regions, including the NAc. Here we review studies using a combination of in vivo and ex vivo electrophysiology, pharmacogenetic and optogenetic manipulations that have characterized the functional neuroanatomy of inhibitory circuits in the mesolimbic system, and describe how GABA neurons of the VTA regulate reward and aversion-related learning. We also discuss pharmacogenetic manipulation of this system with benzodiazepines (BDZs, a class of addictive drugs, which act directly on GABAA receptors located on GABA neurons of the VTA. The results gathered with each of these approaches suggest that VTA GABA neurons bi-directionally modulate activity of local DA neurons, underlying reward or aversion at the behavioural level. Conversely, long-range GABA projections from the VTA to the NAc selectively target cholinergic interneurons (CINs to pause their firing and temporarily reduce cholinergic tone in the NAc, which modulates associative learning. Further characterization of inhibitory circuit function within and beyond the VTA is needed in order to fully understand the function of the mesolimbic system under normal and pathological conditions.

  10. Decreased auditory GABA+ concentrations in presbycusis demonstrated by edited magnetic resonance spectroscopy. (United States)

    Gao, Fei; Wang, Guangbin; Ma, Wen; Ren, Fuxin; Li, Muwei; Dong, Yuling; Liu, Cheng; Liu, Bo; Bai, Xue; Zhao, Bin; Edden, Richard A E


    Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the central auditory system. Altered GABAergic neurotransmission has been found in both the inferior colliculus and the auditory cortex in animal models of presbycusis. Edited magnetic resonance spectroscopy (MRS), using the MEGA-PRESS sequence, is the most widely used technique for detecting GABA in the human brain. However, to date there has been a paucity of studies exploring changes to the GABA concentrations in the auditory region of patients with presbycusis. In this study, sixteen patients with presbycusis (5 males/11 females, mean age 63.1 ± 2.6 years) and twenty healthy controls (6 males/14 females, mean age 62.5 ± 2.3 years) underwent audiological and MRS examinations. Pure tone audiometry from 0.125 to 8 kHz and tympanometry were used to assess the hearing abilities of all subjects. The pure tone average (PTA; the average of hearing thresholds at 0.5, 1, 2 and 4 kHz) was calculated. The MEGA-PRESS sequence was used to measure GABA+ concentrations in 4 × 3 × 3 cm(3) volumes centered on the left and right Heschl's gyri. GABA+ concentrations were significantly lower in the presbycusis group compared to the control group (left auditory regions: p = 0.002, right auditory regions: p = 0.008). Significant negative correlations were observed between PTA and GABA+ concentrations in the presbycusis group (r = -0.57, p = 0.02), while a similar trend was found in the control group (r = -0.40, p = 0.08). These results are consistent with a hypothesis of dysfunctional GABAergic neurotransmission in the central auditory system in presbycusis and suggest a potential treatment target for presbycusis.

  11. Electrical stimulation of the substantia nigra reticulata : Detection of neuronal extracellular GABA in the ventromedial thalamus and its regulatory mechanism using microdialysis in awake rats

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    Timmerman, W; Westerink, BHC


    A combination of electrical stimulation and microdialysis was used to study the nigrothalamic gamma aminobutyric acid (GABA)ergic system and its regulatory mechanisms in awake rats. Extracellular GABA levels in the ventromedial nucleus of the thalamus were detected in S-min fractions collected befor

  12. Contribution of polyamines metabolism and GABA shunt to chilling tolerance induced by nitric oxide in cold-stored banana fruit. (United States)

    Wang, Yansheng; Luo, Zisheng; Mao, Linchun; Ying, Tiejin


    Effect of exogenous nitric oxide (NO) on polyamines (PAs) catabolism, γ-aminobutyric acid (GABA) shunt, proline accumulation and chilling injury of banana fruit under cold storage was investigated. Banana fruit treated with NO sustained lower chilling injury index than the control. Notably elevated nitric oxide synthetase activity and endogenous NO level were observed in NO-treated banana fruit. PAs contents in treated fruit were significantly higher than control fruit, due to the elevated activities of arginine decarboxylase and ornithine decarboxylase. NO treatment increased the activities of diamine oxidase, polyamine oxidase and glutamate decarboxylase, while reduced GABA transaminase activity to lower levels compared with control fruit, which resulted the accumulation of GABA. Besides, NO treatment upregulated proline content and significantly enhanced the ornithine aminotransferase activity. These results indicated that the chilling tolerance induced by NO treatment might be ascribed to the enhanced catabolism of PAs, GABA and proline.

  13. Alterations in expression levels of deafness dystonia protein 1 affect mitochondrial morphology

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    Engl, Gertraud; Florian, Stefan; Tranebjærg, Lisbeth


    -C66W was overexpressed. Live cell microscopy of primary fibroblasts derived from DDON patients and of DDP1 downregulated HeLa cells displayed alterations of mitochondrial morphology with notable extensions in the length of mitochondrial tubules, whereas overexpression of DDP1 induced the formation...

  14. Early expression of GABA(A) receptor delta subunit in the neonatal rat hippocampus. (United States)

    Didelon, F; Mladinic', M; Cherubini, E; Bradbury, A


    The cDNA library screening strategy was used to identify the genes encoding for GABA(A) receptor subunits in the rat hippocampus during development. With this technique, genes encoding eleven GABA(A) receptor subunits were identified. The alpha5 subunit was by far the most highly expressed, followed by the gamma2, alpha2 and alpha4 subunits respectively. The expression of the beta2, alpha1, gamma1, beta1 and beta3 subunits was moderate, although that of the alpha3 and delta subunits was weak. In situ hybridization experiments, using digoxigenin-labeled cRNA probes, confirmed that the delta subunit was expressed in the neonatal as well as in the adult hippocampus, and is likely to form functional receptors in association with other subunits of the GABA(A) receptor. When the more sensitive RT-PCR approach was used, the gamma3 subunit was also detected, suggesting that this subunit is present in the hippocampus during development but at low levels of expression. The insertion of the delta subunit into functional GABA(A) receptors may enhance the efficacy of GABA in the immediate postnatal period when this amino acid is still exerting a depolarizing and excitatory action.

  15. Early expression of KCC2 in rat hippocampal cultures augments expression of functional GABA synapses. (United States)

    Chudotvorova, Ilona; Ivanov, Anton; Rama, Sylvain; Hübner, Christian A; Pellegrino, Christophe; Ben-Ari, Yehezkel; Medina, Igor


    The development of GABAergic synapses is associated with an excitatory to inhibitory shift of the actions of GABA because of a reduction of [Cl-]i. This is due to a delayed postnatal expression of the K+ -Cl- cotransporter KCC2, which has low levels at birth and peaks during the first few postnatal weeks. Whether the expression of the cotransporter and the excitatory to inhibitory shift have other consequences on the operation of GABA(A) receptors and synapses is not yet known. We have now expressed KCC2 in immature neurones at an early developmental stage and determined the consequences on the formation of GABA and glutamate synapses. We report that early expression of the cotransporter selectively enhances GABAergic synapses: there is a significant increase of the density of GABA(A) receptors and synapses and an increase of the frequency of GABAergic miniature postsynaptic currents. The density of glutamate synapses and frequency of AMPA miniature postsynaptic currents are not affected. We conclude that the expression of KCC2 and the reduction of [Cl-]i play a critical role in the construction of GABAergic networks that extends beyond the excitatory to inhibitory shift of the actions of GABA.

  16. CSF GABA is reduced in first-episode psychosis and associates to symptom severity. (United States)

    Orhan, F; Fatouros-Bergman, H; Goiny, M; Malmqvist, A; Piehl, F; Cervenka, S; Collste, K; Victorsson, P; Sellgren, C M; Flyckt, L; Erhardt, S; Engberg, G


    Schizophrenia is characterized by a multiplicity of symptoms arising from almost all domains of mental function. γ-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain and is increasingly recognized to have a significant role in the pathophysiology of the disorder. In the present study, cerebrospinal fluid (CSF) concentrations of GABA were analyzed in 41 first-episode psychosis (FEP) patients and 21 age- and sex-matched healthy volunteers by high-performance liquid chromatography. We found lower CSF GABA concentration in FEP patients compared with that in the healthy volunteers, a condition that was unrelated to antipsychotic and/or anxiolytic medication. Moreover, lower CSF GABA levels were associated with total and general score of Positive and Negative Syndrome Scale, illness severity and probably with a poor performance in a test of attention. This study offers clinical in vivo evidence for a potential role of GABA in early-stage schizophrenia.Molecular Psychiatry advance online publication, 14 March 2017; doi:10.1038/mp.2017.25.

  17. GABA/benzodiazepine receptor complex in long-sleep and short-sleep mice

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    Marley, R.J.


    LS mice are more sensitive to benzodiazepine-induced anesthesia; however, the two lines do not differ in their hypothermic response to flurazepam. SS mice are more resistant to 3-mercaptopropionic acid-induced seizures and more sensitive to the anticonvulsant effects of benzodiazepines. The various correlates of GABA and benzodiazepine actions probably are the results of different mechanisms of action and/or differential regional control. Bicuculline competition for /sup 3/H-GABA binding sites is greater in SS cerebellar tissue and /sup 3/H-flunitrazepam binding is greater in the mid-brain region of LS mice. GABA enhancement of /sup 3/H-flunitrazepma binding is greater in SS mice. Ethanol also enhances /sup 3/H-flunitrazepam binding and increases the levels of /sup 3/H-flunitrazepam binding above those observed for GABA. Using correlational techniques on data from LS and SS mice and several inbred mouse strains, it was demonstrated that a positive relationship exists between the degree of receptor coupling within the GABA receptor complex and the degree of resistance to seizures.

  18. Alterations in male sexual behaviour, attractiveness and testosterone levels induced by an adult-onset calorie restriction regimen. (United States)

    Govic, Antonina; Levay, Elizabeth A; Hazi, Agnes; Penman, Jim; Kent, Stephen; Paolini, Antonio G


    Despite an abundance of research on calorie restriction (CR) altering gonadal and appetite regulating hormones, the sexual behavioural consequences of CR remain to be examined systematically. This study compared the sexual behaviour, partner preference, serum testosterone and leptin levels of male adult Hooded Wistar rats administered a CR (continuous 25%, 50% CR or a temporary restriction) with ad libitum fed controls. The temporary restriction (Previous CR) failed to alter sexual behaviour, partner preference and levels of testosterone and leptin. The moderately 25% CR males did not demonstrate an impairment in sexual behaviour but did demonstrate a reduced level of attractiveness to females in one measure of partner preference. Sexual performance was affected by a substantial CR, as the CR 50% group exhibited a longer latency to the first intromission, indicating alteration in sexual arousal. Females also consistently demonstrated a clear preference for the control group compared to the CR 50% group. These findings indicate a possible reduction in the overall reproductive potential of the substantially CR animals. Testosterone levels were equally suppressed by both the 25% and 50% CR, while leptin levels were only reduced in the CR 50% group. Leptin, rather than testosterone, may have influenced the impairment in sexual behaviour only demonstrated by the substantially CR animals. Testosterone, may, however, play a role in modulating the preference of control over CR males, as attractiveness was totally reduced by a substantial CR, and partially reduced by a moderate restricted regimen.

  19. Reduction of GABA/sub B/ receptor binding induced by climbing fiber degeneration in the rat cerebellum

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    Kato, K.; Fukuda, H.


    When the rat cerebellar climbing fibers degenerated, as induced by lesioning the inferior olive with 3-acetylpyridine (3-AP), GABA/sub B/ receptor binding determined with /sup 3/H-(+/-)baclofen was reduced in the cerebellum but not in the cerebral cortex of rats. Computer analysis of saturation data revealed two components of the binding sites, and indicated that decrease of the binding in the cerebellum was due to reduction in receptor density, mainly of the high-affinity sites, the B/sub max/ of which was reduced to one-third that in the control animals. In vitro treatment with 3-AP, of the membranes prepared from either the cerebellum or the cerebral cortex, induced no alteration in the binding sites, thereby indicating that the alteration of GABA/sub B/ sites induced by in vivo treatment with 3-AP is not due to a direct action of 3-AP on the receptor. GABA/sub A/ and benzodiazepine receptor binding labelled with /sup 3/H-muscimol and /sup 3/H-diazepam, respectively, in both of brain regions was not affected by destruction of the inferior olive. These results provide evidence that some of the GABA/sub B/ sites but neither GABA/sub A/ nor benzodiazepine receptors in the cerebellum are located at the climbing fiber terminals. 28 references, 4 figures, 2 tables.

  20. Reproducibility and effect of tissue composition on cerebellar γ-aminobutyric acid (GABA) MRS in an elderly population. (United States)

    Long, Zaiyang; Dyke, Jonathan P; Ma, Ruoyun; Huang, Chaorui C; Louis, Elan D; Dydak, Ulrike


    MRS provides a valuable tool for the non-invasive detection of brain γ-aminobutyric acid (GABA) in vivo. GABAergic dysfunction has been observed in the aging cerebellum. The study of cerebellar GABA changes is of considerable interest in understanding certain age-related motor disorders. However, little is known about the reproducibility of GABA MRS in an aged population. Therefore, this study aimed to explore the feasibility and reproducibility of GABA MRS in the aged cerebellum at 3.0 T and to examine the effect of differing tissue composition on GABA measurements. MRI and (1)H MRS examinations were performed on 10 healthy elderly volunteers (mean age, 75.2 ± 6.5 years) using a 3.0-T Siemens Tim Trio scanner. Among them, five subjects were scanned twice to assess the short-term reproducibility. The MEGA-PRESS (Mescher-Garwood point-resolved spectroscopy) J-editing sequence was used for GABA detection in two volumes of interest (VOIs) in the left and right cerebellar dentate. MRS data processing and quantification were performed with LCModel 6.3-0L using two separate basis sets, generated from density matrix simulations using published values for chemical shifts and J couplings. Raw metabolite levels from LCModel outputs were corrected for cerebrospinal fluid contamination and relaxation. GABA-edited spectra yielded robust and stable GABA measurements with averaged intra-individual coefficients of variation for corrected GABA+ between 4.0 ± 2.8% and 13.4 ± 6.3%, and inter-individual coefficients of variation between 12.6% and 24.2%. In addition, there was a significant correlation between GABA+ obtained with the two LCModel basis sets. Overall, our results demonstrated the feasibility and reproducibility of cerebellar GABA-edited MRS at 3.0 T in an elderly population. This information might be helpful for studies using this technique to study GABA changes in normal or diseased aging brain, e.g. for power calculations and the interpretation of longitudinal

  1. Traumatic brain injury and the effects of diazepam, diltiazem, and MK-801 on GABA-A receptor subunit expression in rat hippocampus

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    Meyer Rebecca C


    Full Text Available Abstract Background Excitatory amino acid release and subsequent biochemical cascades following traumatic brain injury (TBI have been well documented, especially glutamate-related excitotoxicity. The effects of TBI on the essential functions of inhibitory GABA-A receptors, however, are poorly understood. Methods We used Western blot procedures to test whether in vivo TBI in rat altered the protein expression of hippocampal GABA-A receptor subunits α1, α2, α3, α5, β3, and γ2 at 3 h, 6 h, 24 h, and 7 days post-injuy. We then used pre-injury injections of MK-801 to block calcium influx through the NMDA receptor, diltiazem to block L-type voltage-gated calcium influx, or diazepam to enhance chloride conductance, and re-examined the protein expressions of α1, α2, α3, and γ2, all of which were altered by TBI in the first study and all of which are important constituents in benzodiazepine-sensitive GABA-A receptors. Results Western blot analysis revealed no injury-induced alterations in protein expression for GABA-A receptor α2 or α5 subunits at any time point post-injury. Significant time-dependent changes in α1, α3, β3, and γ2 protein expression. The pattern of alterations to GABA-A subunits was nearly identical after diltiazem and diazepam treatment, and MK-801 normalized expression of all subunits 24 hours post-TBI. Conclusions These studies are the first to demonstrate that GABA-A receptor subunit expression is altered by TBI in vivo, and these alterations may be driven by calcium-mediated cascades in hippocampal neurons. Changes in GABA-A receptors in the hippocampus after TBI may have far-reaching consequences considering their essential importance in maintaining inhibitory balance and their extensive impact on neuronal function.

  2. GABA and glutamate pathways are spatially and developmentally affected in the brain of Mecp2-deficient mice.

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    Rita El-Khoury

    Full Text Available Proper brain functioning requires a fine-tuning between excitatory and inhibitory neurotransmission, a balance maintained through the regulation and release of glutamate and GABA. Rett syndrome (RTT is a rare genetic disorder caused by mutations in the methyl-CpG binding protein 2 (MECP2 gene affecting the postnatal brain development. Dysfunctions in the GABAergic and glutamatergic systems have been implicated in the neuropathology of RTT and a disruption of the balance between excitation and inhibition, together with a perturbation of the electrophysiological properties of GABA and glutamate neurons, were reported in the brain of the Mecp2-deficient mouse. However, to date, the extent and the nature of the GABA/glutamate deficit affecting the Mecp2-deficient mouse brain are unclear. In order to better characterize these deficits, we simultaneously analyzed the GABA and glutamate levels in Mecp2-deficient mice at 2 different ages (P35 and P55 and in several brain areas. We used a multilevel approach including the quantification of GABA and glutamate levels, as well as the quantification of the mRNA and protein expression levels of key genes involved in the GABAergic and glutamatergic pathways. Our results show that Mecp2-deficient mice displayed regional- and age-dependent variations in the GABA pathway and, to a lesser extent, in the glutamate pathway. The implication of the GABA pathway in the RTT neuropathology was further confirmed using an in vivo treatment with a GABA reuptake inhibitor that significantly improved the lifespan of Mecp2-deficient mice. Our results confirm that RTT mouse present a deficit in the GABAergic pathway and suggest that GABAergic modulators could be interesting therapeutic agents for this severe neurological disorder.

  3. γ-Aninobutyric acid (GABA suppresses antigen-specific immune responses in ovalbumin γ(OVA-immunized BALB/c mice

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    Tohru Sakai


    Full Text Available γ-Aminobutruic acid (GABA is known to be a ubiquitous inhibitory neurotransmitter in the central nervous system. Furthermore, recent studies have shown that GABA modulates cardiovascular and respiratory functions. In this study, we examined the effect of GABA on antigen (Ag-specific immune responses and elucidated the mechanisms underlying those effects in ovalbumin (OVA-immunized BALB/c mice. OVA-specific proliferative responses were decreased in mice that had been administered 20 mg/kg GABA compared to those in control mice without reduction in responses to anti-CD3 monoclonal (mAb. The levels of OVA-specific IgG, IgG1 and IgG2a were also decreased in mice that had been administered GABA. However, GABA administration did not influence the TNP-specific IgM and IgG levels. Ag-presenting activity of CD11c+ dendritic cells from GABA-treated mice was less than that of cells from control mice. These results suggest that the suppressive effect of GABA on Ag-specific immune responses contributes to the reduction of antigen-presenting function on CD11c+ dendritic cells.

  4. Presynaptic Na+-dependent transport and exocytose of GABA and glutamate in brain in hypergravity. (United States)

    Borisova, T.; Pozdnyakova, N.; Krisanova, N.; Himmelreich, N.

    γ-Aminobutyric acid (GABA) and L-glutamate are the most widespread neurotransmitter amino acids in the mammalian central nervous system. GABA is now widely recognized as the major inhibitory neurotransmitter. L-glutamate mediates the most of excitatory synaptic neurotransmission in the brain. They involved in the main aspects of normal brain function. The nerve terminals (synaptosomes) offer several advantages as a model system for the study of general mechanisms of neurosecretion. Our data allowed to conclude that exposure of animals to hypergravity (centrifugation of rats at 10G for 1 hour) had a profound effect on synaptic processes in brain. Comparative analysis of uptake and release of GABA and glutamate have demonstrated that hypergravity loading evokes oppositely directed alterations in inhibitory and excitatory signal transmission. We studied the maximal velocities of [^3H]GABA reuptake and revealed more than twofold enhancement of GABA transporter activity (Vmax rises from 1.4 |pm 0.3 nmol/min/mg of protein in the control group to 3.3 ± 0.59 nmol/min/mg of protein for animals exposed to hypergravity (P ≤ 0.05)). Recently we have also demonstrated the significant lowering of glutamate transporter activity (Vmax of glutamate reuptake decreased from 12.5 ± 3.2 nmol/min/mg of protein in the control group to 5.6 ± 0.9 nmol/min/mg of protein in the group of animals, exposed to the hypergravity stress (P ≤ 0.05)). Significant changes occurred in release of neurotransmitters induced by stimulating exocytosis with the agents, which depolarized nerve terminal plasma membrane. Depolarization-evoked Ca2+-stimulated release was more abundant for GABA (7.2 ± 0.54% and 11,74 ±1,2 % of total accumulated label for control and hypergravity, respectively (P≤0.05)) and was essentially less for glutamate (14.4 ± 0.7% and 6.2 ± 1.9%) after exposure of animals to centrifuge induced artificial gravity. Changes observed in depolarization-evoked exocytotic release

  5. Glutamate and GABA in appetite regulation

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    Teresa Cardoso Delgado


    Full Text Available Appetite is regulated by a coordinated interplay between gut, adipose tissue and brain. A primary site for the regulation of appetite is the hypothalamus where interaction between orexigenic neurons, expressing Neuropeptide Y/Agouti-related protein, and anorexigenic neurons, expressing Pro-opiomelanocortin cocaine/Amphetamine-related transcript, controls energy homeostasis. Within the hypothalamus, several peripheral signals have been shown to modulate the activity of these neurons, including the orexigenic peptide ghrelin and the anorexigenic hormones insulin and leptin. In addition to the accumulated knowledge on neuropeptide signaling, presence and function of amino acid neurotransmitters in key hypothalamic neurons brought a new light into appetite regulation. Therefore, the principal aim of this review will be to describe the current knowledge of the role of amino acid neurotransmitters in the mechanism of neuronal activation during appetite regulation and the associated neuronal-astrocytic metabolic coupling mechanisms.Glutamate and GABA dominate synaptic transmission in the hypothalamus and administration of their receptors agonists into hypothalamic nuclei stimulates feeding. By using 13C High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy based analysis, the Cerdán group has shown that increased neuronal firing in mice hypothalamus, as triggered by appetite during the feeding-fasting paradigm, may stimulate the use of lactate as neuronal fuel leading to increased astrocytic glucose consumption and glycolysis. Moreover, fasted mice showed increased hypothalamic [2-13C]GABA content, which may be explained by the existence of GABAergic neurons in key appetite regulation hypothalamic nuclei. Interestingly, increased [2-13C]GABA concentration in the hypothalamus of fasted animals appears to result mainly from reduction in GABA metabolizing pathways, rather than increased GABA synthesis by augmented activity of the

  6. Chronic treatment with glucocorticoids alters rat hippocampal and prefrontal cortical morphology in parallel with endogenous agmatine and arginine decarboxylase levels. (United States)

    Zhu, Meng-Yang; Wang, Wei-Ping; Huang, Jingjing; Regunathan, Soundar


    In the present study, we examined the possible effect of chronic treatment with glucocorticoids on the morphology of the rat brain and levels of endogenous agmatine and arginine decarboxylase (ADC) protein, the enzyme essential for agmatine synthesis. Seven-day treatment with dexamethasone, at a dose (10 and 50 mug/kg/day) associated to stress effects contributed by glucocorticoids, did not result in obvious morphologic changes in the medial prefrontal cortex and hippocampus, as measured by immunocytochemical staining with beta-tubulin III. However, 21-day treatment (50 mug/kg/day) produced noticeable structural changes such as the diminution and disarrangement of dendrites and neurons in these areas. Simultaneous treatment with agmatine (50 mg/kg/day) prevented these morphological changes. Further measurement with HPLC showed that endogenous agmatine levels in the prefrontal cortex and hippocampus were significantly increased after 7-day treatments with dexamethasone in a dose-dependent manner. On the contrary, 21-day treatment with glucocorticoids robustly reduced agmatine levels in these regions. The treatment-caused biphasic alterations of endogenous agmatine levels were also seen in the striatum and hypothalamus. Interestingly, treatment with glucocorticoids resulted in a similar change of ADC protein levels in most brain areas to endogenous agmatine levels: an increase after 7-day treatment versus a reduction after 21-day treatment. These results demonstrated that agmatine has neuroprotective effects against structural alterations caused by glucocorticoids in vivo. The parallel alterations in the endogenous agmatine levels and ADC expression in the brain after treatment with glucocorticoids indicate the possible regulatory effect of these stress hormones on the synthesis and metabolism of agmatine in vivo.

  7. Excitatory GABA in rodent developing neocortex in vitro. (United States)

    Rheims, Sylvain; Minlebaev, Marat; Ivanov, Anton; Represa, Alfonso; Khazipov, Rustem; Holmes, Gregory L; Ben-Ari, Yehezkel; Zilberter, Yuri


    GABA depolarizes immature cortical neurons. However, whether GABA excites immature neocortical neurons and drives network oscillations as in other brain structures remains controversial. Excitatory actions of GABA depend on three fundamental parameters: the resting membrane potential (Em), reversal potential of GABA (E(GABA)), and threshold of action potential generation (Vthr). We have shown recently that conventional invasive recording techniques provide an erroneous estimation of these parameters in immature neurons. In this study, we used noninvasive single N-methyl-d-aspartate and GABA channel recordings in rodent brain slices to measure both Em and E(GABA) in the same neuron. We show that GABA strongly depolarizes pyramidal neurons and interneurons in both deep and superficial layers of the immature neocortex (P2-P10). However, GABA generates action potentials in layer 5/6 (L5/6) but not L2/3 pyramidal cells, since L5/6 pyramidal cells have more depolarized resting potentials and more hyperpolarized Vthr. The excitatory GABA transiently drives oscillations generated by L5/6 pyramidal cells and interneurons during development (P5-P12). The NKCC1 co-transporter antagonist bumetanide strongly reduces [Cl(-)]i, GABA-induced depolarization, and network oscillations, confirming the importance of GABA signaling. Thus a strong GABA excitatory drive coupled with high intrinsic excitability of L5/6 pyramidal neurons and interneurons provide a powerful mechanism of synapse-driven oscillatory activity in the rodent neocortex in vitro. In the companion paper, we show that the excitatory GABA drives layer-specific seizures in the immature neocortex.


    Directory of Open Access Journals (Sweden)

    Robert Colquhoun Shields


    Full Text Available Streptococcus mutans activates multiple cellular processes in response to the formation of a complex between comX-inducing peptide (XIP and the ComR transcriptional regulator. Bulk phase and microfluidic experiments previously revealed that ComR-dependent activation of comX is altered by pH and by carbohydrate source. Biofilm formation is a major factor in bacterial survival and virulence in the oral cavity. Here, we sought to determine the response of S. mutans biofilm cells to XIP during different stages of biofilm maturation. Using flow cytometry and confocal microscopy, we showed that exogenous addition of XIP to early biofilms resulted in robust comX activation. However, as the biofilms matured, increasing amounts of XIP were required to activate comX expression. Single-cell analysis demonstrated that the entire population was responding to XIP with activation of comX in early biofilms, but only a sub-population was responding in mature biofilms. The sub-population response of mature biofilms was retained when the cells were dispersed and then treated with XIP. The proportion and intensity of the bi-modal response of mature biofilm cells was altered in mutants lacking the Type II toxins MazF and RelE, or in a strain lacking the (pppGpp synthase/hydrolase RelA. Thus, competence signaling is markedly altered in cells growing in mature biofilms, and pathways that control cell death and growth/survival decisions modulate activation of comX expression in these sessile populations.

  9. Alteration in the cytokine levels and histopathological damage in common carp induced by glyphosate. (United States)

    Ma, Junguo; Li, Xiaoyu


    Glyphosate is one of the most frequently used herbicides, and it has been demonstrated to generate a series of toxicological problems in animals and humans. However, relatively little is known about the effects of glyphosate on the immune system of fish. In the present study, the acute toxicity of glyphosate on common carp was first determined; then, the contents of interferon-γ (IFN-γ), interleukin-1β (IL-1β), and tumor necrosis factor -α (TNF-α) and histopathological alterations in the liver, kidneys, and spleen of common carp exposed to 52.08 or 104.15 mg L(-1) of glyphosate for 168 h were also determined and evaluated. The results of the acute toxicity tests showed that the 96 h LC50 of glyphosate for common carp was 520.77 mg L(-1). Moreover, sub-acute exposure of glyphosate altered the contents of IFN-γ, IL-1β, and TNF-α in fish immune organs. For example, there was a remarkable increase in the IFN-γ content in the kidneys, while there was a decrease in the liver and spleen. The IL-1β content increased in liver and kidneys, but it decreased in the spleen, and TNF-α mainly increased in the fish liver, kidneys, and spleen. In addition, glyphosate-exposure also caused remarkable histopathological damage in the fish liver, kidneys, and spleen. These results suggest that glyphosate-caused cytokine alterations may result in an immune suppression or excessive activation in the treated common carp as well as may cause immune dysfunction or reduced immunity. In conclusion, glyphosate has immunotoxic effects on common carp.

  10. Growth of Streptococcus mutans in Biofilms Alters Peptide Signaling at the Sub-population Level (United States)

    Shields, Robert C.; Burne, Robert A.


    Streptococcus mutans activates multiple cellular processes in response to the formation of a complex between comX-inducing peptide (XIP) and the ComR transcriptional regulator. Bulk phase and microfluidic experiments previously revealed that ComR-dependent activation of comX is altered by pH and by carbohydrate source. Biofilm formation is a major factor in bacterial survival and virulence in the oral cavity. Here, we sought to determine the response of S. mutans biofilm cells to XIP during different stages of biofilm maturation. Using flow cytometry and confocal microscopy, we showed that exogenous addition of XIP to early biofilms resulted in robust comX activation. However, as the biofilms matured, increasing amounts of XIP were required to activate comX expression. Single-cell analysis demonstrated that the entire population was responding to XIP with activation of comX in early biofilms, but only a sub-population was responding in mature biofilms. The sub-population response of mature biofilms was retained when the cells were dispersed and then treated with XIP. The proportion and intensity of the bi-modal response of mature biofilm cells was altered in mutants lacking the Type II toxins MazF and RelE, or in a strain lacking the (p)ppGpp synthase/hydrolase RelA. Thus, competence signaling is markedly altered in cells growing in mature biofilms, and pathways that control cell death and growth/survival decisions modulate activation of comX expression in these sessile populations. PMID:27471495

  11. GABA(A) receptors in visual and auditory cortex and neural activity changes during basic visual stimulation. (United States)

    Qin, Pengmin; Duncan, Niall W; Wiebking, Christine; Gravel, Paul; Lyttelton, Oliver; Hayes, Dave J; Verhaeghe, Jeroen; Kostikov, Alexey; Schirrmacher, Ralf; Reader, Andrew J; Northoff, Georg


    Recent imaging studies have demonstrated that levels of resting γ-aminobutyric acid (GABA) in the visual cortex predict the degree of stimulus-induced activity in the same region. These studies have used the presentation of discrete visual stimulus; the change from closed eyes to open also represents a simple visual stimulus, however, and has been shown to induce changes in local brain activity and in functional connectivity between regions. We thus aimed to investigate the role of the GABA system, specifically GABA(A) receptors, in the changes in brain activity between the eyes closed (EC) and eyes open (EO) state in order to provide detail at the receptor level to complement previous studies of GABA concentrations. We conducted an fMRI study involving two different modes of the change from EC to EO: an EO and EC block design, allowing the modeling of the haemodynamic response, followed by longer periods of EC and EO to allow the measuring of functional connectivity. The same subjects also underwent [(18)F]Flumazenil PET to measure GABA(A) receptor binding potentials. It was demonstrated that the local-to-global ratio of GABA(A) receptor binding potential in the visual cortex predicted the degree of changes in neural activity from EC to EO. This same relationship was also shown in the auditory cortex. Furthermore, the local-to-global ratio of GABA(A) receptor binding potential in the visual cortex also predicted the change in functional connectivity between the visual and auditory cortex from EC to EO. These findings contribute to our understanding of the role of GABA(A) receptors in stimulus-induced neural activity in local regions and in inter-regional functional connectivity.

  12. Alterations in Lipid Levels of Mitochondrial Membranes Induced by Amyloid-ß: A Protective Role of Melatonin

    Directory of Open Access Journals (Sweden)

    Sergio A. Rosales-Corral


    Full Text Available Alzheimer pathogenesis involves mitochondrial dysfunction, which is closely related to amyloid-ß (Aß generation, abnormal tau phosphorylation, oxidative stress, and apoptosis. Alterations in membranal components, including cholesterol and fatty acids, their characteristics, disposition, and distribution along the membranes, have been studied as evidence of cell membrane alterations in AD brain. The majority of these studies have been focused on the cytoplasmic membrane; meanwhile the mitochondrial membranes have been less explored. In this work, we studied lipids and mitochondrial membranes in vivo, following intracerebral injection of fibrillar amyloid-ß (Aß. The purpose was to determine how Aß may be responsible for beginning of a vicious cycle where oxidative stress and alterations in cholesterol, lipids and fatty acids, feed back on each other to cause mitochondrial dysfunction. We observed changes in mitochondrial membrane lipids, and fatty acids, following intracerebral injection of fibrillar Aß in aged Wistar rats. Melatonin, a well-known antioxidant and neuroimmunomodulator indoleamine, reversed some of these alterations and protected mitochondrial membranes from obvious damage. Additionally, melatonin increased the levels of linolenic and n-3 eicosapentaenoic acid, in the same site where amyloid ß was injected, favoring an endogenous anti-inflammatory pathway.

  13. Alterations in Lipid Levels of Mitochondrial Membranes Induced by Amyloid-β: A Protective Role of Melatonin (United States)

    Rosales-Corral, Sergio A.; Lopez-Armas, Gabriela; Cruz-Ramos, Jose; Melnikov, Valery G.; Tan, Dun-Xian; Manchester, Lucien C.; Munoz, Ruben; Reiter, Russel J.


    Alzheimer pathogenesis involves mitochondrial dysfunction, which is closely related to amyloid-β (Aβ) generation, abnormal tau phosphorylation, oxidative stress, and apoptosis. Alterations in membranal components, including cholesterol and fatty acids, their characteristics, disposition, and distribution along the membranes, have been studied as evidence of cell membrane alterations in AD brain. The majority of these studies have been focused on the cytoplasmic membrane; meanwhile the mitochondrial membranes have been less explored. In this work, we studied lipids and mitochondrial membranes in vivo, following intracerebral injection of fibrillar amyloid-β (Aβ). The purpose was to determine how Aβ may be responsible for beginning of a vicious cycle where oxidative stress and alterations in cholesterol, lipids and fatty acids, feed back on each other to cause mitochondrial dysfunction. We observed changes in mitochondrial membrane lipids, and fatty acids, following intracerebral injection of fibrillar Aβ in aged Wistar rats. Melatonin, a well-known antioxidant and neuroimmunomodulator indoleamine, reversed some of these alterations and protected mitochondrial membranes from obvious damage. Additionally, melatonin increased the levels of linolenic and n-3 eicosapentaenoic acid, in the same site where amyloid β was injected, favoring an endogenous anti-inflammatory pathway. PMID:22666620

  14. 塞络通胶囊对大鼠多发性脑梗死恢复期Glu和GABA合成以及NMDA受体亚型表达的影响%Effect of Sailuotong capsule on Glu and GABA levels as well as NMDA receptor subtypes expression in recovery period of rat multiple cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    徐立; 宋文婷; 林成仁; 任建勋; 刘建勋; 姚明江; 王光蕊


    The rat model of multi-infarct was adopted in this study to elucidate the protective mechanism of Sailuotong capsule (Sailuotong) in recovery period of multiple cerebral infarction. The effects of Sailuotong on levels of Glu, GABA and the expression of NMDA receptor subtypes including NRI, NR2A and NR2B, were detected. The multi-infarct model rats were established by injecting embolizing microsphere via internal carotid artery, and were given Sailuotong treatment (16.5 and 33.0 mg·kg-1) for 60 days. The pathological changes in brain ultrastructure were observed by transmission electron microscope. The levels of Glu and GABA in brain tissue were measured with high performance liquid chromatography. The expression of NMDA receptors including NRI, NR2A and NR2B in neurons was evaluated by immunohistochemical staining. Compared with the sham rats, abnormal changes were observed in ultrastructures of neurons, neuroglia cells and synapses of model rat brains. Moreover, significant decrease of Glu and GABA, as well as the elevated expression of NRI, NR2A and NR2B were detected in brain tissues. Sailuotong (16.5 and 33.0 mg-kg"1) could improve ultrastructure of cerebral tissue, facilitate synthesis of Glu and GABA, and down-regulate expression of NR1, NR2A and NR2B in neurons. The results demonstrated that Sailuotong could exert neuroprotective effects to some extent in the recovery phase of multiple cerebral infarction by promoting expression of NMDA receptors and synthesis of Glu and GABA.%观察塞络通胶囊(塞络通)对大鼠多发性脑梗死恢复期脑组织中神经递质谷氨酸(Glu)和γ-氨基丁酸(GABA)含量以及NMDA受体亚型NR1、NR2A和NR2B表达的影响,阐述塞络通在脑缺血后恢复期对脑组织保护的作用机制.通过大鼠颈内动脉注射微球血管栓塞剂的方法建立多发性脑梗死大鼠模型,在脑梗死后10天采用不同剂量的寒络通(16.5及33.0 mg·kg 1)连续干预60天.采用透射电子显微镜观察脑

  15. Block of GABA(A) receptor ion channel by penicillin: electrophysiological and modeling insights toward the mechanism. (United States)

    Rossokhin, Alexey V; Sharonova, Irina N; Bukanova, Julia V; Kolbaev, Sergey N; Skrebitsky, Vladimir G


    GABA(A) receptors (GABA(A)R) mainly mediate fast inhibitory neurotransmission in the central nervous system. Different classes of modulators target GABA(A)R properties. Penicillin G (PNG) belongs to the class of noncompetitive antagonists blocking the open GABA(A)R and is a prototype of β-lactam antibiotics. In this study, we combined electrophysiological and modeling approaches to investigate the peculiarities of PNG blockade of GABA-activated currents recorded from isolated rat Purkinje cells and to predict the PNG binding site. Whole-cell patch-сlamp recording and fast application system was used in the electrophysiological experiments. PNG block developed after channel activation and increased with membrane depolarization suggesting that the ligand binds within the open channel pore. PNG blocked stationary component of GABA-activated currents in a concentration-dependent manner with IC50 value of 1.12mM at -70mV. The termination of GABA and PNG co-application was followed by a transient tail current. Protection of the tail current from bicuculline block and dependence of its kinetic parameters on agonist affinity suggest that PNG acts as a sequential open channel blocker that prevents agonist dissociation while the channel remains blocked. We built the GABA(A)R models based on nAChR and GLIC structures and performed an unbiased systematic search of the PNG binding site. Monte-Carlo energy minimization was used to find the lowest energy binding modes. We have shown that PNG binds close to the intracellular vestibule. In both models the maximum contribution to the energy of ligand-receptor interactions revealed residues located on the level of 2', 6' and 9' rings formed by a bundle of M2 transmembrane segments, indicating that these residues most likely participate in PNG binding. The predicted structural models support the described mechanism of PNG block.

  16. Long-term variation in above and belowground plant inputs alters soil organic matter biogeochemistry at the molecular-level (United States)

    Simpson, M. J.; Pisani, O.; Lin, L.; Lun, O.; Simpson, A.; Lajtha, K.; Nadelhoffer, K. J.


    The long-term fate of soil carbon reserves with global environmental change remains uncertain. Shifts in moisture, altered nutrient cycles, species composition, or rising temperatures may alter the proportions of above and belowground biomass entering soil. However, it is unclear how long-term changes in plant inputs may alter the composition of soil organic matter (SOM) and soil carbon storage. Advanced molecular techniques were used to assess SOM composition in mineral soil horizons (0-10 cm) after 20 years of Detrital Input and Removal Treatment (DIRT) at the Harvard Forest. SOM biomarkers (solvent extraction, base hydrolysis and cupric (II) oxide oxidation) and both solid-state and solution-state nuclear magnetic resonance (NMR) spectroscopy were used to identify changes in SOM composition and stage of degradation. Microbial activity and community composition were assessed using phospholipid fatty acid (PLFA) analysis. Doubling aboveground litter inputs decreased soil carbon content, increased the degradation of labile SOM and enhanced the sequestration of aliphatic compounds in soil. The exclusion of belowground inputs (No roots and No inputs) resulted in a decrease in root-derived components and enhanced the degradation of leaf-derived aliphatic structures (cutin). Cutin-derived SOM has been hypothesized to be recalcitrant but our results show that even this complex biopolymer is susceptible to degradation when inputs entering soil are altered. The PLFA data indicate that changes in soil microbial community structure favored the accelerated processing of specific SOM components with littler manipulation. These results collectively reveal that the quantity and quality of plant litter inputs alters the molecular-level composition of SOM and in some cases, enhances the degradation of recalcitrant SOM. Our study also suggests that increased litterfall is unlikely to enhance soil carbon storage over the long-term in temperate forests.

  17. Alterations of serum levels of BDNF-related miRNAs in patients with depression.

    Directory of Open Access Journals (Sweden)

    You-Jie Li

    Full Text Available Depression is a serious and potentially life-threatening mental disorder with unknown etiology. Emerging evidence shows that brain-derived neurotrophic factor (BDNF and microRNAs (miRNAs play critical roles in the etiology of depression. Here this study was aimed to identify and characterize the roles of BDNF and its putative regulatory miRNAs in depression. First, we identified that miR-182 may be a putative miRNA that regulates BDNF levels by bioinformatic studies, and characterized the effects of miR-182 on the BDNF levels using cell-based studies, side by side with miR-132 (a known miRNA that regulates BDNF expression. We showed that treatment of miR-132 and miR-182 respectively decreased the BDNF protein levels in a human neuronal cell model, supporting the regulatory roles of miR-132 and miR-182 on the BDNF expression. Furthermore, we explored the roles of miR-132 and miR-182 on the BDNF levels in depression using human subjects by assessing their serum levels. Compared with the healthy controls, patients with depression showed lower serum BDNF levels (via the enzyme-linked immunosorbent assays and higher serum miR-132 and miR-182 levels (via the real-time PCR. Finally, the Pearson's (or Spearman's correlation coefficient was calculated to study whether there was a relationship among the Self-Rating Depression Scale score, the serum BDNF levels, and serum BDNF-related miRNA levels. Our results revealed that there was a significant negative correlation between the SDS scores and the serum BDNF levels, and a positive correlation between the SDS scores and miR-132 levels. In addition, we found a reverse relationship between the serum BDNF levels and the miR-132/miR-182 levels in depression. Collectively, we provided evidence supporting that miR-182 is a putative BDNF-regulatory miRNA, and suggested that the serum BDNF and its related miRNAs may be utilized as important biomarkers in the diagnosis or as therapeutic targets of depression.

  18. Altered metabolism of copper, zinc, and magnesium is associated with increased levels of glycated hemoglobin in patients with diabetes mellitus. (United States)

    Viktorínová, Alena; Toserová, Eva; Krizko, Marián; Duracková, Zdenka


    Diabetes mellitus (DM) is associated with the alterations in the metabolism of copper (Cu), zinc (Zn), and magnesium (Mg). The aim of the present study was to investigate plasma levels of these elements in patients with DM and in healthy subjects. Association between glycated hemoglobin and levels of metals was also evaluated. We studied 36 subjects with DM (type 1, 11; type 2, 25) and 34 healthy subjects matched for age, sex, and duration of diabetes. Plasma concentrations of Cu, Zn, and Mg were measured by atomic absorption spectrometry. An imbalance in the levels of studied metals was observed in both type 1 and type 2 DM. We found higher levels of Cu (P diabetic complications.

  19. Genetic variations altering FSH action affect circulating hormone levels as well as follicle growth in healthy peripubertal girls

    DEFF Research Database (Denmark)

    Busch, Alexander S.; Hagen, Casper P; Almstrup, Kristian


    STUDY QUESTION: Do variants of the genes encoding follicle stimulating hormone (FSH) beta subunit (B) and FSH receptor (R) impact circulating reproductive hormone levels and ovarian follicle maturation in healthy peripubertal girls? SUMMARY ANSWER: FSHB and FSHR genetic variants exert, alone...... or their combination, distinct effects on reproductive hormone levels as well as ovarian follicle maturation in healthy peripubertal girls. WHAT IS KNOWN ALREADY: FSHB and FSHR genetic variants impact reproductive hormone levels as well as associated pathologies in women. While FSHR c. 2039A>G is known to alter...... as pathological conditions is being increasingly elucidated. The variant triplet set might serve as diagnostic and pharmacogenetic marker. For the first time, we show an additional effect of FSHR c.-29G>A on serum FSH levels in healthy girls. Moreover, morphological data suggest impaired FSH-induced maturation...

  20. Distribution and ultrastructure of neurons in opossum piriform cortex displaying immunoreactivity to GABA and GAD and high-affinity tritiated GABA uptake

    Energy Technology Data Exchange (ETDEWEB)

    Haberly, L.B.; Hansen, D.J.; Feig, S.L.; Presto, S.


    GABAergic neurons have been identified in the piriform cortex of the opossum at light and electron microscopic levels by immunocytochemical localization of GABA and the GABA-synthesizing enzyme glutamic acid decarboxylase and by autoradiographic visualization of high-affinity /sup 3/H-GABA uptake. Four major neuron populations have been distinguished on the basis of soma size, shape, and segregation at specific depths and locations: large horizontal cells in layer Ia of the anterior piriform cortex, small globular cells with thin dendrites concentrated in layers Ib and II of the posterior piriform cortex, and multipolar and fusiform cells concentrated in the deep part of layer III in anterior and posterior parts of the piriform cortex and the subjacent endopiriform nucleus. All four populations were well visualized with both antisera, but the large layer Ia horizontal cells displayed only very light /sup 3/H-GABA uptake, thus suggesting a lack of local axon collaterals or lack of high-affinity GABA uptake sites. The large, ultrastructurally distinctive somata of layer Ia horizontal cells receive a very small number of symmetrical synapses; the thin, axonlike dendrites of small globular cells are exclusively postsynaptic and receive large numbers of both symmetrical and asymmetrical synapses, in contrast to somata which receive a small number of both types; and the deep multipolar and fusiform cells receive a highly variable number of symmetrical and asymmetrical synapses on somata and proximal dendrites. Labeled puncta of axon terminal dimensions were found in large numbers in the neuropil surrounding pyramidal cell somata in layer II and in the endopiriform nucleus. Moderately large numbers of labeled puncta were found in layer I at the depth of pyramidal cell apical dendrites with greater numbers in layer Ia at the depth of distal apical segments than in layer Ib.

  1. The Glutamine-Glutamate/GABA Cycle

    DEFF Research Database (Denmark)

    Walls, Anne B; Waagepetersen, Helle S; Bak, Lasse Kristoffer;


    inhibitor methionine sulfoximine and the tricarboxylic acid cycle (aconitase) inhibitors fluoro-acetate and -citrate. Acetate is metabolized exclusively by glial cells, and [(13)C]acetate is thus capable when used in combination with magnetic resonance spectroscopy or mass spectrometry, to provide......The operation of a glutamine-glutamate/GABA cycle in the brain consisting of the transfer of glutamine from astrocytes to neurons and neurotransmitter glutamate or GABA from neurons to astrocytes is a well-known concept. In neurons, glutamine is not only used for energy production and protein...... synthesis, as in other cells, but is also an essential precursor for biosynthesis of amino acid neurotransmitters. An excellent tool for the study of glutamine transfer from astrocytes to neurons is [(14)C]acetate or [(13)C]acetate and the glial specific enzyme inhibitors, i.e. the glutamine synthetase...

  2. Decreased GABA receptor in the cerebral cortex of epileptic rats: effect of Bacopa monnieri and Bacoside-A

    Directory of Open Access Journals (Sweden)

    Mathew Jobin


    Full Text Available Abstact Background Gamma amino butyric acid (GABA, the principal inhibitory neurotransmitter in the cerebral cortex, maintains the inhibitory tones that counter balances neuronal excitation. When this balance is perturbed, seizures may ensue. Methods In the present study, alterations of the general GABA, GABAA and GABAB receptors in the cerebral cortex of the epileptic rat and the therapeutic application of Bacopa monnieri were investigated. Results Scatchard analysis of [3H]GABA, [3H]bicuculline and [3H]baclofen in the cerebral cortex of the epileptic rat showed significant decrease in Bmax (P Aά1, GABAAγ, GABAAδ, GABAB and GAD where down regulated (P Aά5 subunit and Cyclic AMP responsible element binding protein were up regulated. Confocal imaging study confirmed the decreased GABA receptors in epileptic rats. Epileptic rats have deficit in radial arm and Y maze performance. Conclusions Bacopa monnieri and Bacoside-A treatment reverses epilepsy associated changes to near control suggesting that decreased GABA receptors in the cerebral cortex have an important role in epileptic occurrence; Bacopa monnieri and Bacoside-A have therapeutic application in epilepsy management.

  3. Metabolic alterations derived from absence of Two-Pore Channel 1 at cardiac level

    Indian Academy of Sciences (India)



    Two-pore channels (TPCs or TPCNs) are novel voltage-gated ion channels that have been postulated to act as Ca2+ and/orNa+ channels expressed exclusively in acidic organelles such as endosomes and lysosomes. TPCNs participate in theregulation of diverse biological processes and recently have been proposed to be involved in the pathophysiology ofmetabolic disorders such as obesity, fatty liver disease and type 2 diabetes mellitus. Due to the importance of thesepathologies in the development of cardiovascular diseases, we aimed to study the possible role of two-pore channel 1(TPCN1) in the regulation of cardiac metabolism. To explore the cardiac function of TPCN1, we developed proteomicapproaches as 2-DE-MALDI-MS and LC-MALDI-MS in the cardiac left ventricle of TPCN1 KO and WT mice, and foundalterations in several proteins implicated in glucose and fatty acid metabolism in TPCN1 KO vs. WT mice. The resultsconfirmed the altered expression of HFABP, a key fatty acid transport protein, and of enolase and PGK1, the key enzymes inthe glycolytic process. Finally, in vitro experiments performed in neonatal rat cardiomyocytes, in which TPCN1 was silencedusing siRNAs, confirmed that the downregulation of TPCN1 gene expression increased 2-deoxy-D-[3H]-glucose uptake andGLUT4 mobilization into cell peripherals in cardiac cells. Our results are the first to suggest a potential role for TPCNs incardiac metabolism regulation.

  4. The TOC159 mutant of Arabidopsis thaliana accumulates altered levels of saturated and polyunsaturated fatty acids. (United States)

    Afitlhile, Meshack; Fry, Morgan; Workman, Samantha


    We evaluated whether the TOC159 mutant of Arabidopsis called plastid protein import 2-2 (ppi2-2) accumulates normal levels of fatty acids, and transcripts of fatty acid desaturases and galactolipid synthesis enzymes. The ppi2-2 mutant accumulates decreased pigments and total fatty acid content. The MGD1 gene was downregulated and the mutant accumulates decreased levels of monogalactosyldiacylglycerol (MGDG) and 16:3, which suggests that the prokaryotic pathway was impaired in the mutant. The HY5 gene, which encodes long hypocotyl5 transcription factor, was upregulated in the mutant. The DGD1 gene, an HY5 target was marginally increased and the mutant accumulates digalactosyldiacylglycerol at the control level. The mutant had increased expression of 3-ketoacyl-ACP synthase II gene, which encodes a plastid enzyme that elongates 16:0 to 18:0. Interestingly, glycerolipids in the mutant accumulate increased levels of 18:0. A gene that encodes stearoyl-ACP desaturase (SAD) was expressed at the control level and 18:1 was increased, which suggest that SAD may be strongly regulated at the posttranscriptional level. The molar ratio of MGDG to bilayer forming plastid lipids was decreased in the cold-acclimated wild type but not in the ppi2-2 mutant. This indicates that the mutant was unresponsive to cold-stress, and is consistent with increased levels of 18:0, and decreased 16:3 and 18:3 in the ppi2-2 mutant. Overall, these data indicate that a defective Toc159 receptor impaired the synthesis of MGDG, and affected desaturation of 16 and 18-carbon fatty acids. We conclude that expression of the MGD1 gene and synthesis of MGDG are tightly linked to plastid biogenesis.

  5. Association of a Human FABP1 Gene Promoter Region Polymorphism with Altered Serum Triglyceride Levels.

    Directory of Open Access Journals (Sweden)

    Xian-E Peng

    Full Text Available Liver fatty acid-binding protein (L-FABP, also known as fatty acid-binding protein 1 (FABP1, is a key regulator of hepatic lipid metabolism. Elevated FABP1 levels are associated with an increased risk of cardiovascular disease (CVD and metabolic syndromes. In this study, we examine the association of FABP1 gene promoter variants with serum FABP1 and lipid levels in a Chinese population. Four promoter single-nucleotide polymorphisms (SNPs of FABP1 gene were genotyped in a cross-sectional survey of healthy volunteers (n = 1,182 from Fuzhou city of China. Results showed that only the rs2919872 G>A variant was significantly associated with serum TG concentration(P = 0.032.Compared with the rs2919872 G allele, rs2919872 A allele contributed significantly to reduced serum TG concentration, and this allele dramatically decreased the FABP1 promoter activity(P < 0.05. The rs2919872 A allele carriers had considerably lower serum FABP1 levels than G allele carriers (P < 0.01. In the multivariable linear regression analysis, the rs2919872 A allele was negatively associated with serum FABP1 levels (β = -0.320, P = 0.003, while serum TG levels were positively associated with serum FABP1 levels (β = 0.487, P = 0.014. Our data suggest that compared with the rs2919872 G allele, the rs2919872 A allele reduces the transcriptional activity of FABP1 promoter, and thereby may link FABP1 gene variation to TG level in humans.

  6. Prenatal exposure to zinc oxide particles alters monoaminergic neurotransmitter levels in the brain of mouse offspring. (United States)

    Okada, Yuka; Tachibana, Ken; Yanagita, Shinya; Takeda, Ken


    Zinc oxide (ZnO) nano-sized particles (NPs) are beneficial materials used for sunscreens and cosmetics. Although ZnO NPs are widely used for cosmetics, the health effects of exposure during pregnancy on offspring are largely unknown. Here we investigated the effects of prenatal exposure to ZnO NPs on the monoaminergic system of the mouse brain. Subcutaneous administration of ZnO NPs to the pregnant ICR mice (total 500 μg/mouse) were carried out and then measured the levels of dopamine (DA), serotonin (5-HT), and noradrenalin, and their metabolites in 9 regions of the brain of offspring (6-week-old) using high performance liquid chromatography (HPLC). HPLC analysis demonstrated that DA levels were increased in hippocampus in the ZnO NP exposure group. In the levels of DA metabolites, homovanillic acid was increased in the prefrontal cortex and hippocampus, and 3, 4-dihydroxyphenylacetic acid was increased in the prefrontal cortex by prenatal ZnO NP exposure. Furthermore, DA turnover levels were increased in the prefrontal cortex, neostriatum, nucleus accumbens, and amygdala in the ZnO NP exposure group. We also found changes of the levels of serotonin in the hypothalamus, and of the levels of 5-HIAA (5-HT metabolite) in the prefrontal cortex and hippocampus in the ZnO NP-exposed group. The levels of 5-HT turnover were increased in each of the regions except for the cerebellum by prenatal ZnO NP exposure. The present study indicated that prenatal exposure to ZnO NPs might disrupt the monoaminergic system, and suggested the possibility of detrimental effects on the mental health of offspring.

  7. CSF beta-amyloid levels are altered in narcolepsy: a link with the inflammatory hypothesis? (United States)

    Liguori, Claudio; Placidi, Fabio; Albanese, Maria; Nuccetelli, Marzia; Izzi, Francesca; Marciani, Maria Grazia; Mercuri, Nicola Biagio; Bernardini, Sergio; Romigi, Andrea


    Narcolepsy is characterized by hypocretin deficiency due to the loss of hypothalamic orexinergic neurons, and is associated with both the human leucocyte antigen DQB1*06:02 and the T cell receptor polymorphism. The above relationship suggests autoimmune/inflammatory processes underlying the loss of orexinergic neurons in narcolepsy. To test the autoimmune/inflammatory hypothesis by means of cerebrospinal fluid (CSF) levels of beta-amyloid1-42 and/or total tau proteins in a sample of narcoleptic patients, we analysed 16 narcoleptic patients and 16 healthy controls. Beta-amyloid1-42 CSF levels were significantly lower in narcoleptic patients compared with healthy controls. We also documented pathologically low levels of CSF beta-amyloid1-42 (narcolepsy and the prevalence of an 'amyloidogenic' pathway caused by the deficiency of the alpha-secretases enzymes.

  8. Low-level red laser therapy alters effects of ultraviolet C radiation on Escherichia coli cells. (United States)

    Canuto, K S; Sergio, L P S; Guimarães, O R; Geller, M; Paoli, F; Fonseca, A S


    Low-level lasers are used at low power densities and doses according to clinical protocols supplied with laser devices or based on professional practice. Although use of these lasers is increasing in many countries, the molecular mechanisms involved in effects of low-level lasers, mainly on DNA, are controversial. In this study, we evaluated the effects of low-level red lasers on survival, filamentation, and morphology of Escherichia colicells that were exposed to ultraviolet C (UVC) radiation. Exponential and stationary wild-type and uvrA-deficientE. coli cells were exposed to a low-level red laser and in sequence to UVC radiation. Bacterial survival was evaluated to determine the laser protection factor (ratio between the number of viable cells after exposure to the red laser and UVC and the number of viable cells after exposure to UVC). Bacterial filaments were counted to obtain the percentage of filamentation. Area-perimeter ratios were calculated for evaluation of cellular morphology. Experiments were carried out in duplicate and the results are reported as the means of three independent assays. Pre-exposure to a red laser protected wild-type and uvrA-deficient E. coli cells against the lethal effect of UVC radiation, and increased the percentage of filamentation and the area-perimeter ratio, depending on UVC fluence and physiological conditions in the cells. Therapeutic, low-level red laser radiation can induce DNA lesions at a sub-lethal level. Consequences to cells and tissues should be considered when clinical protocols based on this laser are carried out.

  9. Low-level red laser therapy alters effects of ultraviolet C radiation on Escherichia coli cells

    Directory of Open Access Journals (Sweden)

    K.S. Canuto


    Full Text Available Low-level lasers are used at low power densities and doses according to clinical protocols supplied with laser devices or based on professional practice. Although use of these lasers is increasing in many countries, the molecular mechanisms involved in effects of low-level lasers, mainly on DNA, are controversial. In this study, we evaluated the effects of low-level red lasers on survival, filamentation, and morphology of Escherichia coli cells that were exposed to ultraviolet C (UVC radiation. Exponential and stationary wild-type and uvrA-deficient E. coli cells were exposed to a low-level red laser and in sequence to UVC radiation. Bacterial survival was evaluated to determine the laser protection factor (ratio between the number of viable cells after exposure to the red laser and UVC and the number of viable cells after exposure to UVC. Bacterial filaments were counted to obtain the percentage of filamentation. Area-perimeter ratios were calculated for evaluation of cellular morphology. Experiments were carried out in duplicate and the results are reported as the means of three independent assays. Pre-exposure to a red laser protected wild-type and uvrA-deficient E. coli cells against the lethal effect of UVC radiation, and increased the percentage of filamentation and the area-perimeter ratio, depending on UVC fluence and physiological conditions in the cells. Therapeutic, low-level red laser radiation can induce DNA lesions at a sub-lethal level. Consequences to cells and tissues should be considered when clinical protocols based on this laser are carried out.

  10. Low-level red laser therapy alters effects of ultraviolet C radiation on Escherichia coli cells

    Energy Technology Data Exchange (ETDEWEB)

    Canuto, K.S.; Guimaraes, O.R.; Geller, M. [Centro Universitario Serra dos Orgaos, Teresopolis, RJ (Brazil). Centro de Ciencias da Saude; Sergio, L.P.S. [Instituto de Biologia Roberto Alcantara Gomes, Rio de Janeiro, RJ (Brazil). Departamento de Biofisica e Biometria; Paoli, F. [Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, MG (Brazil). Departamento de Morfologia; Fonseca, A.S., E-mail: [Universidade Federal do Estado do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Ciencias Fisiologicas


    Low-level lasers are used at low power densities and doses according to clinical protocols supplied with laser devices or based on professional practice. Although use of these lasers is increasing in many countries, the molecular mechanisms involved in effects of low-level lasers, mainly on DNA, are controversial. In this study, we evaluated the effects of low-level red lasers on survival, filamentation, and morphology of Escherichia coli cells that were exposed to ultraviolet C (UVC) radiation. Exponential and stationary wild-type and uvrA-deficient E. coli cells were exposed to a low-level red laser and in sequence to UVC radiation. Bacterial survival was evaluated to determine the laser protection factor (ratio between the number of viable cells after exposure to the red laser and UVC and the number of viable cells after exposure to UVC). Bacterial filaments were counted to obtain the percentage of filamentation. Area-perimeter ratios were calculated for evaluation of cellular morphology. Experiments were carried out in duplicate and the results are reported as the means of three independent assays. Pre-exposure to a red laser protected wild-type and uvrA-deficient E. coli cells against the lethal effect of UVC radiation, and increased the percentage of filamentation and the area-perimeter ratio, depending on UVC fluence and physiological conditions in the cells. Therapeutic, low-level red laser radiation can induce DNA lesions at a sub-lethal level. Consequences to cells and tissues should be considered when clinical protocols based on this laser are carried out. (author)

  11. Nerve Regenerative Effects of GABA-B Ligands in a Model of Neuropathic Pain

    Directory of Open Access Journals (Sweden)

    Valerio Magnaghi


    Full Text Available Neuropathic pain arises as a direct consequence of a lesion or disease affecting the peripheral somatosensory system. It may be associated with allodynia and increased pain sensitivity. Few studies correlated neuropathic pain with nerve morphology and myelin proteins expression. Our aim was to test if neuropathic pain is related to nerve degeneration, speculating whether the modulation of peripheral GABA-B receptors may promote nerve regeneration and decrease neuropathic pain. We used the partial sciatic ligation- (PSL- induced neuropathic model. The biochemical, morphological, and behavioural outcomes of sciatic nerve were analysed following GABA-B ligands treatments. Simultaneous 7-days coadministration of baclofen (10 mg/kg and CGP56433 (3 mg/kg alters tactile hypersensitivity. Concomitantly, specific changes of peripheral nerve morphology, nerve structure, and myelin proteins (P0 and PMP22 expression were observed. Nerve macrophage recruitment decreased and step coordination was improved. The PSL-induced changes in nociception correlate with altered nerve morphology and myelin protein expression. Peripheral synergic effects, via GABA-B receptor activation, promote nerve regeneration and likely ameliorate neuropathic pain.

  12. Target-specific suppression of GABA release from parvalbumin interneurons in the basolateral amygdala by dopamine. (United States)

    Chu, Hong-Yuan; Ito, Wataru; Li, Jiayang; Morozov, Alexei


    Dopamine (DA) in the basolateral amygdala (BLA) promotes fear learning by disinhibiting principal neurons (PNs) and enabling synaptic plasticity in their sensory inputs. While BLA interneurons (INs) are heterogeneous, it is unclear which interneuron subtypes decrease GABAergic input to PNs in the presence of DA. Here, using cell type-selective photostimulation by channelrhodopsin 2 in BLA slices from mouse brain, we examined the role of parvalbumin-positive INs (PV-INs), the major interneuronal subpopulation in BLA, in the disinhibitory effect of DA. We found that DA selectively suppressed GABAergic transmission from PV-INs to PNs by acting on presynaptic D(2) receptors, and this effect was mimicked by Rp-cAMP, an inhibitor of cAMP-dependent signaling. In contrast, DA did not alter GABA release from PV-INs to INs. Furthermore, neither suppressing cAMP-dependent signaling by Rp-cAMP nor enhancing it by forskolin altered GABA release from PV-INs to BLA INs. Overall, DA disinhibits BLA, at least in part, by suppressing GABA release from PV-INs in the target cell-specific manner that results from differential control of this release by cAMP-dependent signaling.

  13. Spatial variability and reproducibility of GABA-edited MEGA-LASER 3D-MRSI in the brain at 3 T. (United States)

    Hnilicová, Petra; Považan, Michal; Strasser, Bernhard; Andronesi, Ovidiu C; Gajdošík, Martin; Dydak, Ulrike; Ukropec, Jozef; Dobrota, Dušan; Trattnig, Siegfried; Bogner, Wolfgang


    The reproducibility of gamma-aminobutyric acid (GABA) quantification results, obtained with MRSI, was determined on a 3 T MR scanner in healthy adults. In this study, a spiral-encoded, GABA-edited, MEGA-LASER MRSI sequence with real-time motion-scanner-instability corrections was applied for robust 3D mapping of neurotransmitters in the brain. In particular, the GABA(+) (i.e. GABA plus macromolecule contamination) and Glx (i.e. glutamate plus glutamine contamination) signal was measured. This sequence enables 3D-MRSI with about 3 cm(3) nominal resolution in about 20 min. Since reliable quantification of GABA is challenging, the spatial distribution of the inter-subject and intra-subject variability of GABA(+) and Glx levels was studied via test-retest assessment in 14 healthy volunteers (seven men-seven women). For both inter-subject and intra-subject repeated measurement sessions a low coefficient of variation (CV) and a high intraclass correlation coefficient (ICC) were found for GABA(+) and Glx ratios across all evaluated voxels (intra-/inter-subject: GABA(+) ratios, CV ~ 8%-ICC > 0.75; Glx ratios, CV ~ 6%-ICC > 0.70). The same was found in selected brain regions for Glx ratios versus GABA(+) ratios (CV varied from about 5% versus about 8% in occipital and parietal regions, to about 8% versus about 10% in the frontal area, thalamus, and basal ganglia). These results provide evidence that 3D mapping of GABA(+) and Glx using the described methodology provides high reproducibility for application in clinical and neuroscientific studies.

  14. GABA uptake inhibitors. Design, molecular pharmacology and therapeutic aspects

    DEFF Research Database (Denmark)

    Krogsgaard-Larsen, P; Frølund, B; Frydenvang, Karla Andrea


    GABAA receptor agonists. The availability of these compounds made it possible to study the pharmacology of the GABA uptake systems and the GABAA receptors separately. Based on extensive cellular and molecular pharmacological studies using 23, 24, and a number of mono- and bicyclic analogues, it has been...... demonstrated that neuronal and glial GABA transport mechanisms have dissimilar substrate specificities. With GABA transport mechanisms as pharmacological targets, strategies for pharmacological interventions with the purpose of stimulating GABA neurotransmission seem to be (1) effective blockade of neuronal...... recently been reported as the most selective glial GABA uptake inhibitor so far known and may be a useful tool for further elucidation of the pharmacology of GABA transporters. In recent years, a variety of lipophilic analogues of the amino acids 23 and 24 have been developed, and one of these compounds...

  15. Venous plasma levels of endothelin-1 are not altered immediately after nitroglycerin infusion in healthy subjects

    DEFF Research Database (Denmark)

    Thomsen, L L; Iversen, Helle Klingenberg; Emmeluth, C;


    Endothelin-1 and nitric oxide play an important regulatory role in the control of vascular smooth muscle tone. Nitroglycerin (NTG), a nitric oxide donating drug, may inhibit endothelin production. In this double-blind placebo-controlled crossover study, plasma levels of endothelin-1 were measured...

  16. Eradication of Helicobacter pylori infection favourably affects altered gastric mucosal MMP-9 levels

    NARCIS (Netherlands)

    Kubben, F.J.G.M.; Sier, C.F.M.; Schram, M.; Witte, T.A.M.C.; Veenendaal, R.A.; Duijn, W. van; Verheijen, J.H.; Hanemaaijer, R.; Lamers, C.B.H.W.; Verspaget, H.W.


    Background: Helicobacter pylori gastritis is recognized as an important pathogenetic factor in peptic ulcer disease and gastric carcinogenesis, and is accompanied by strongly enhanced gastric mucosal matrix metalloproteinase-9 (MMP-9) levels. Aim: This study was performed to investigate whether H. p

  17. High homocysteine levels prevent via H2 S the CoCl2 -induced alteration of lymphocyte viability. (United States)

    Bruzzese, Laurie; Fenouillet, Emmanuel; Fromonot, Julien; Durand-Gorde, Josée-Martine; Condo, Jocelyne; Kipson, Nathalie; Mottola, Giovanna; Deharo, Pierre; Guieu, Régis; Ruf, Jean


    High homocysteine (HCy) levels are associated with lymphocyte-mediated inflammatory responses that are sometimes in turn related to hypoxia. Because adenosine is a potent lymphocyte suppressor produced in hypoxic conditions and shares metabolic pathways with HCy, we addressed the influence of high HCy levels on the hypoxia-induced, adenosine-mediated, alteration of lymphocyte viability. We treated mitogen-stimulated human lymphocytes isolated from healthy individuals and the human lymphoma T-cell line CEM with cobalt chloride (CoCl2 )to reproduce hypoxia. We found that CoCl2 -altered cell viability was dose-dependently reversed using HCy. In turn, the HCy effect was inhibited using DL-propargylglycine, a specific inhibitor of the hydrogen sulphide (H2 S)-synthesizing enzyme cystathionine-γ-lyase involved in HCy catabolism. We then addressed the intracellular metabolic pathway of adenosine and HCy, and the role of the adenosine A2A receptor (A2 A R). We observed that: (i) hypoxic conditions lowered the intracellular concentration of HCy by increasing adenosine production, which resulted in high A2 A R expression and 3', 5'-cyclic adenosine monophosphate production; (ii) increasing intracellular HCy concentration reversed the hypoxia-induced adenosinergic signalling despite high adenosine concentration by promoting both S-adenosylhomocysteine and H2 S production; (iii) DL-propargylglycine that inhibits H2 S production abolished the HCy effect. Together, these data suggest that high HCy levels prevent, via H2 S production and the resulting down-regulation of A2 A R expression, the hypoxia-induced adenosinergic alteration of lymphocyte viability. We point out the relevance of these mechanisms in the pathophysiology of cardiovascular diseases.

  18. Treating enhanced GABAergic inhibition in Down syndrome: use of GABA α5-selective inverse agonists. (United States)

    Martínez-Cué, Carmen; Delatour, Benoît; Potier, Marie-Claude


    Excess inhibition in the brain of individuals carrying an extra copy of chromosome 21 could be responsible for cognitive deficits observed throughout their lives. A change in the excitatory/inhibitory balance in adulthood would alter synaptic plasticity, potentially triggering learning and memory deficits. γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mature central nervous system and binds to GABAA receptors, opens a chloride channel, and reduces neuronal excitability. In this review we discuss methods to alleviate neuronal inhibition in a mouse model of Down syndrome, the Ts65Dn mouse, using either an antagonist (pentylenetetrazol) or two different inverse agonists selective for the α5-subunit containing receptor. Both inverse agonists, which reduce inhibitory GABAergic transmission, could rescue learning and memory deficits in Ts65Dn mice. We also discuss safety issues since modulation of the excitatory-inhibitory balance to improve cognition without inducing seizures remains particularly difficult when using GABA antagonists.

  19. Levels of estradiol and testosterone are altered in Chinese men with sexual dysfunction. (United States)

    Wu, F; Chen, T; Mao, S; Jiang, H; Ding, Q; Xu, G


    An estimated 20-30% of adult men have at least one manifestation of sexual dysfunction, the most common of which are premature ejaculation (PE) and erectile dysfunction (ED). Emerging evidence has suggested an association between the regulation of hormones with the processes of erection and ejaculation. In this study, we aim to investigate the relationship between sexual dysfunction, namely, PE and ED, and the levels and ratios of estradiol to testosterone in Chinese men. A retrospective case-control study was performed involving 878 male patients aged from 18 to 74 years (mean: 36 years). The ratio of estradiol to testosterone was significantly higher for subjects with ED (7.45 ± 3.09 × 10(-3) ; p < 0.001), and combined PE and ED (6.66 ± 3.05 × 10(-3) ; p = 0.032) compared with that of the control group (6.01 ± 2.61 × 10(-3) ). The ratio was also significantly higher for ED patients when compared with PE patients (5.26 ± 2.18 × 10(-3) ; p < 0.001). Furthermore, compared with the control group, subjects with PE had similar levels of estradiol (95.47 ± 37.86 pmol/L vs. 94.12 ± 32.32 pmol/L; p = 0.678) but significantly higher levels of testosterone (18.66 ± 6.03 nmol/L vs. 16.82 ± 4.93 nmol/L; p < 0.001). This contrasted with the ED group, which showed similar levels of testosterone (16.96 ± 5.86 nmol/L vs. 16.82 ± 4.93 nmol/L; p = 0.773) and significantly higher levels of estradiol (116.88 ± 40.81 pmol/L vs. 94.12 ± 32.32 pmol/L; p < 0.001) compared with control. Subjects with combined ED and PE also had a significantly higher level of estradiol (104.98 ± 43.99 pmol/L vs. 94.12 ± 32.32 pmol/L; p = 0.014) and similar levels of testosterone (17.30 ± 7.23 nmol/L vs. 16.82 ± 4.93 nmol/L; p = 0.503) compared with control. In conclusion, this study involving Chinese males with sexual dysfunction reports, for the first time, that there is an association between sexual dysfunction

  20. High-fat diet transition reduces brain DHA levels associated with altered brain plasticity and behaviour. (United States)

    Sharma, Sandeep; Zhuang, Yumei; Gomez-Pinilla, Fernando


    To assess how the shift from a healthy diet rich in omega-3 fatty acids to a diet rich in saturated fatty acid affects the substrates for brain plasticity and function, we used pregnant rats fed with omega-3 supplemented diet from their 2nd day of gestation period as well as their male pups for 12 weeks. Afterwards, the animals were randomly assigned to either a group fed on the same diet or a group fed on a high-fat diet (HFD) rich in saturated fats for 3 weeks. We found that the HFD increased vulnerability for anxiety-like behavior, and that these modifications harmonized with changes in the anxiety-related NPY1 receptor and the reduced levels of BDNF, and its signalling receptor pTrkB, as well as the CREB protein. Brain DHA contents were significantly associated with the levels of anxiety-like behavior in these rats.

  1. Estrogen alters baseline and inflammatory-induced cytokine levels independent from hypothalamic-pituitary-adrenal axis activity. (United States)

    Shivers, Kai-Yvonne; Amador, Nicole; Abrams, Lisa; Hunter, Deirtra; Jenab, Shirzad; Quiñones-Jenab, Vanya


    Although estrogen reduces inflammatory-mediated pain responses, the mechanisms behind its effects are unclear. This study investigated if estrogen modulates inflammatory signaling by reducing baseline or inflammation-induced cytokine levels in the injury-site, serum, dorsal root ganglia (DRG) and/or spinal cord. We further tested whether estrogen effects on cytokine levels are in part mediated through hypothalamic-pituitary-adrenal (HPA) axis activation. Lumbar DRG, spinal cord, serum, and hind paw tissue were analyzed for cytokine levels in 17β-estradiol-(20%) or vehicle-(100% cholesterol) treated female rats following ovariectomy/sham adrenalectomy (OVX), adrenalectomy/sham ovariectomy (ADX) or ADX+OVX operation at baseline and post formalin injection. Formalin significantly increased pro-inflammatory interleukin (IL)-6 levels in the paw, as well as pro- and anti-inflammatory cytokine levels in the DRG, spinal cord and serum in comparison to naïve conditions. Estrogen replacement significantly increased anti-inflammatory IL-10 levels in the DRG. Centrally, estradiol significantly decreased pro-inflammatory tumor necrosis factor (TNF)-α and IL-1β levels, as well as IL-10 levels, in the spinal cord in comparison to cholesterol treatment. At both sites, most estradiol modulatory effects occurred irrespective of pain or surgical condition. Estradiol alone had no influence on cytokine release in the paw or serum, indicating that estrogen effects were site-specific. Although cytokine levels were altered between surgical conditions at baseline and following formalin administration, ADX operation did not significantly reverse estradiol's modulation of cytokine levels. These results suggest that estrogen directly regulates cytokines independent of HPA axis activity in vivo, in part by reducing cytokine levels in the spinal cord.

  2. Repeated Exposure to Neurotoxic Levels of Chlorpyriphos Alters Hippocampal Expression of Neurotrophins and Neuropeptides (United States)


    K.M., 2012. Increased nociceptive sensitivity and nociceptin/orphanin FQ levels in a rat model of PTSD. Mol. Pain 8, 76. ...animal was monitored for any pain or discomfort throughout the duration of the study. 2.3. Sample collection, biochemical measurements and...Decreased anxiety, Bipolar disorder (Van Den Eede et al., 2007) Npy Neuropeptide Y NPY Seizure inhibition, Neuroprotection, Pain inhibition, Appetite

  3. Imatinib alters cell viability but not growth factors levels in TM4 Sertoli cells (United States)

    Hashemnia, Seyyed Mohammad Reza; Atari-Hajipirloo, Somayeh; Roshan-Milani, Shiva; Valizadeh, Nasim; Mahabadi, Sonya; Kheradmand, Fatemeh


    Background: The anticancer agent imatinib (IM) is a small molecular analog of ATP that inhibits tyrosine kinase activity of platelet derived growth factors (PDGFs) and stem cell factor (SCF) receptor in cancer cells. However these factors have a key role in regulating growth and development of normal Sertoli, Leydig and germ cells. Objective: The aim of this study was to determine cell viability, PDGF and SCF levels in mouse normal Sertoli cells exposed to IM. Materials and Methods: In this experimental study, the mouse TM4 Sertoli cells were treated with 0, 2.5, 5, 10 and 20 μM IM for 2, 4 or 6 days. The cell viability and growth factors levels were assessed by MTT and ELISA methods, respectively. For statistical analysis, One-Way ANOVA was performed. Results: IM showed significant decrease in Sertoli cell viability compared to control group (p=0.001). However, IM increased PDGF and SCF level insignificantly (p>0.05). Conclusion: Results suggested that IM treatment induced a dose dependent reduction of cell viability in Sertoli cells. It seems that treatment with this anticancer drug is involved in the fertility process. Further studies are needed to evaluate the role of PDGF and SCF in this cell. PMID:27738659

  4. Alteration of cyclic nucleotides levels and oxidative stress in saliva of human subjects with periodontitis. (United States)

    Mashayekhi, Fereshteh; Aghahoseini, Farzaneh; Rezaie, Ali; Zamani, Mohammad J; Khorasani, Reza; Abdollahi, Mohammad


    Experimental findings suggest a protective role for cyclic nucleotides against induction of oxidative stress in saliva. Oxidative stress is a major contributor to the pathogenesis of inflammatory diseases. This study was conducted to evaluate salivary oxidative stress along with cGMP and cAMP levels in periodontitis subjects. cAMP and cGMP are second messengers that have important roles in salivary gland functions. Unstimulated whole saliva samples were obtained from periodontitis patients and age- and sex-matched healthy individuals. Saliva samples were analyzed for thiobarbituric reactive substances (TBARS) as a marker of lipid peroxidation, ferric reducing ability (total antioxidant power, TAP), and levels of cAMP and cGMP. Concentrations of cAMP and cGMP were reduced in the saliva of patients with moderate and severe periodontitis. Saliva of patients with severe periodontitis had higher TBARS and lower TAP than control subjects. The presence of oxidative stress and lower levels of salivary cGMP and cAMP in periodontitis are in association with disease severity.

  5. Altered serous levels of monoamine neurotransmitter metabolites in patiens with refractory and non-refractory depression

    Institute of Scientific and Technical Information of China (English)

    Guiqing Zhang; Yanxia Zhang; Jianxia Yang; Min Hu; Yueqi Zhang; Xia Liang


    The study examined plasma metabolite changes of monoamine neurotransmitters in patients with treatment-resistant depression (TRD) and non-TRD before and after therapy. All 30 TRD and 30 non-TRD patients met the diagnostic criteria for a depressive episode in accordance with the International Classification of Diseases, Tenth Revision. Before treatment, and at 4, 6, and 8 weeks after treatment, the plasma metabolite products of monoamine neurotransmitters in TRD group, including 5-hydroxyindoleacetic acid, 3-methoxy-4-hydroxyphenyl ethylene glycol and homovanillic acid, were significantly lower than those in the non-TRD group. After two types of anti-depressive therapy with 5-serotonin and norepinephrine reuptake inhibitor, combined with psychotherapy, the Hamilton Depression Rating Scale scores were significantly reduced in both groups of patients, and the serous levels of 5-hydroxyindoleacetic acid and 3-methoxy-4-hydroxyphenyl ethylene glycol were significantly increased. In contrast, the homovanillic acid level exhibited no significant change. The levels of plasma metabolite products of peripheral monoamine neurotransmitters in depressive patients may predict the degree of depression and the therapeutic effects of treatment.

  6. Altered α-synuclein, parkin, and synphilin isoform levels in multiple system atrophy brains

    DEFF Research Database (Denmark)

    Brudek, Tomasz; Winge, Kristian; Rasmussen, Nadja Bredo


    Together with Parkinson's disease (PD) and dementia with Lewy bodies, multiple system atrophy (MSA) is a member of a diverse group of neurodegenerative disorders termed α-synucleinopathies. Previously, it has been shown that α-synuclein, parkin, and synphilin-1 display disease-specific transcript......Together with Parkinson's disease (PD) and dementia with Lewy bodies, multiple system atrophy (MSA) is a member of a diverse group of neurodegenerative disorders termed α-synucleinopathies. Previously, it has been shown that α-synuclein, parkin, and synphilin-1 display disease......-specific transcription patterns in frontal cortex in PD, dementia with Lewy bodies, and MSA, and thus may mediate the development of α-synucleinopathies. In this study, the differential expression of α-synuclein isoforms on transcriptional and translational levels was ascertained in MSA patients in comparison with PD...... for parkin and synphilin-1 isoforms. In MSA brains, α-synuclein140 and α-synuclein 112 isoform levels were significantly increased, whereas levels of the α-synuclein 126 isoform were decreased in the substantia nigra, striatum, cerebellar cortex, and nucleus dentatus versus controls. Moreover, in MSA cases...

  7. Hypocretin/orexin antagonism enhances sleep-related adenosine and GABA neurotransmission in rat basal forebrain. (United States)

    Vazquez-DeRose, Jacqueline; Schwartz, Michael D; Nguyen, Alexander T; Warrier, Deepti R; Gulati, Srishti; Mathew, Thomas K; Neylan, Thomas C; Kilduff, Thomas S


    Hypocretin/orexin (HCRT) neurons provide excitatory input to wake-promoting brain regions including the basal forebrain (BF). The dual HCRT receptor antagonist almorexant (ALM) decreases waking and increases sleep. We hypothesized that HCRT antagonists induce sleep, in part, through disfacilitation of BF neurons; consequently, ALM should have reduced efficacy in BF-lesioned (BFx) animals. To test this hypothesis, rats were given bilateral IgG-192-saporin injections, which predominantly targets cholinergic BF neurons. BFx and intact rats were then given oral ALM, the benzodiazepine agonist zolpidem (ZOL) or vehicle (VEH) at lights-out. ALM was less effective than ZOL at inducing sleep in BFx rats compared to controls. BF adenosine (ADO), γ-amino-butyric acid (GABA), and glutamate levels were then determined via microdialysis from intact, freely behaving rats following oral ALM, ZOL or VEH. ALM increased BF ADO and GABA levels during waking and mixed vigilance states, and preserved sleep-associated increases in GABA under low and high sleep pressure conditions. ALM infusion into the BF also enhanced cortical ADO release, demonstrating that HCRT input is critical for ADO signaling in the BF. In contrast, oral ZOL and BF-infused ZOL had no effect on ADO levels in either BF or cortex. ALM increased BF ADO (an endogenous sleep-promoting substance) and GABA (which is increased during normal sleep), and required an intact BF for maximal efficacy, whereas ZOL blocked sleep-associated BF GABA release, and required no functional contribution from the BF to induce sleep. ALM thus induces sleep by facilitating the neural mechanisms underlying the normal transition to sleep.

  8. Altered seawater salinity levels affected growth and photosynthesis ofUlva fasciata (Ulvales, Chlorophyta) germlings

    Institute of Scientific and Technical Information of China (English)

    CHEN Binbin; ZOU Dinghui


    Seawater salinity is greatly influenced by tide, evaporation and rain falls. In this study, we investigated the growth and photosynthetic responses of zygote-derivedUlva fasciata Delile germlings to short-term (minutes) and prolonged (days) exposure to different salinity gradients, to evaluate the effect of salinity variation on the early stage of life history in this seaweed. The results showed that, the maximum net photosynthetic rates (NPRm) ofU. fasciata germlings was observably decreased in desalted (25 and 15) and high (45) salinity seawater in short-term exposure tests (in minutes). However, after 30 min, the photosynthesis activity in medium salinity (25) was maintained at a relative high level (above 70%). After 8 d prolonged culture, the photosynthesis and mean relative growth rate (RGR) of germlings were all markedly lowered, whereas the malondialdehyde (MDA) contents increased as the salinity desalted from 34 to 15. The salinity decrease from 34 to 25 had no significant effect on the RGR, but obviously influenced the morphology of the germlings. High salinity level (45) significantly depressed theRGR and photosynthesis ofU. fasciata germlings, while it notably increased the MDA contents. The results showed that the salinity elevation had more detrimental effects onUlva fasciata germlings than salinity decrease did. The germlings grown at the salinity seawater levels from 25 to 34, performed preferable photosynthetic acclimation both in temporary and prolonged culture. Broad salinity tolerance from 25 to 34 inU. fasciata germlings may have partly evolved as a response to regular diurnal tides.

  9. Cytochrome P450 levels are altered in patients with esophageal squamous-cell carcinoma

    DEFF Research Database (Denmark)

    Bergheim, I.; Wolfgarten, E.; Bollschweiler, E.


    AIM: To investigate the role of cytochrome P450 (CYP) in the carcinogenesis of squamous-cell carcinoma (SCC) in human esophagus by determining expression patterns and protein levels of representative CYPs in esophageal tissue of patients with SCC and controls. METHODS: mRNA expression of CYP2E1...... tissue (e.g. CYP2C8, CYP3A4, CYP3A5, and CYP2E1) between SCC patients and healthy subjects and may contribute to the development of SCC in the esophagus....

  10. F-cell levels are altered with erythrocyte density in sickle cell disease. (United States)

    Basu, Sumanta; Dash, Bisnu Prasad; Patel, Dilip Kumar; Chakravarty, Sudipa; Chakravarty, Amit; Banerjee, Debashis; Chakrabarti, Abhijit


    Lighter cells from density fractionated erythrocytes of sickle cell disease (SCD) patients carry higher amount of externalized phosphatidylserine (PS) and cell surface glycophorins compared to the denser counterparts. Further analysis also revealed that the denser cells contained higher levels of fetal hemoglobin (HbF) compared to the lighter cells, supported by the presence of larger number of F-cells in these populations. In this report, we have found direct evidence on the higher survival of the HbF rich erythrocytes in SCD.

  11. Imipramine reverses alterations in cytokines and BDNF levels induced by maternal deprivation in adult rats. (United States)

    Réus, Gislaine Z; Dos Santos, Maria Augusta B; Abelaira, Helena M; Ribeiro, Karine F; Petronilho, Fabrícia; Vuolo, Francieli; Colpo, Gabriela D; Pfaffenseller, Bianca; Kapczinski, Flávio; Dal-Pizzol, Felipe; Quevedo, João


    A growing body of evidence is pointing toward an association between immune molecules, as well brain-derived neurotrophic factor (BDNF) and the depression. The present study was aimed to evaluate the behavioral and molecular effects of the antidepressant imipramine in maternally deprived adult rats. To this aim, maternally deprived and non-deprived (control group) male rats were treated with imipramine (30mg/kg) once a day for 14 days during their adult phase. Their behavior was then assessed using the forced swimming test. In addition to this, IL-10, TNF-α and IL-1β cytokines were assessed in the serum and cerebrospinal fluid (CSF). In addition, BDNF protein levels were assessed in the prefrontal cortex, hippocampus and amygdala. In deprived rats treated with saline was observed an increase on immobility time, compared with non-deprived rats treated with imipramine (pimipramine treatment reversed the effects of maternal deprivation on BDNF and cytokines levels (pimipramine, it is suggested that classic antidepressants could exert their effects by modulating the immune system.

  12. Forest loss increases insect herbivory levels in human-altered landscapes (United States)

    Dodonov, Pavel; Morante-Filho, José Carlos; Mariano-Neto, Eduardo; Cazetta, Eliana; Andrade, Edyla Ribeiro de; Rocha-Santos, Larissa; Inforzato, Igor; Gomes, Francisco Sanches; Faria, Deborah


    Insect herbivory has been observed to be affected by habitat loss and fragmentation, although the mechanisms by which these anthropogenic disturbances affect this process are not well understood. To aid in clarifying this issue, we assessed the relation between forest cover and leaf damage caused by herbivorous insects on a representative tropical forest understory plant family, the Rubiaceae. We measured leaf area loss of Rubiaceae plants in 20 forest sites located in the Brazilian Atlantic forest, and also tested whether variation in forest cover, abundance of insectivorous birds (predators) and of Rubiaceae plants (resources) could explain the observed variation in leaf damage. Herbivory levels varied between 2.6 and 12.5 percent leaf area lost and increased with decreasing forest cover, whereas the other explanatory variables did not provide additional explanatory power. Therefore, forest loss appears to be the main driver of changes in local herbivory, and ecological processes such as top-down and bottom-up control may not account for the deforestation-related increase in herbivory levels. Other mechanisms, for example leaf quality and/or the influence of the adjoining land uses, have to be explored in future studies.

  13. Repeated exposure to neurotoxic levels of chlorpyrifos alters hippocampal expression of neurotrophins and neuropeptides. (United States)

    Lee, Young S; Lewis, John A; Ippolito, Danielle L; Hussainzada, Naissan; Lein, Pamela J; Jackson, David A; Stallings, Jonathan D


    Chlorpyrifos (CPF), an organophosphorus pesticide (OP), is one of the most widely used pesticides in the world. Subchronic exposures to CPF that do not cause cholinergic crisis are associated with problems in cognitive function (i.e., learning and memory deficits), but the biological mechanism(s) underlying this association remain speculative. To identify potential mechanisms of subchronic CPF neurotoxicity, adult male Long Evans (LE) rats were administered CPF at 3 or 10mg/kg/d (s.c.) for 21 days. We quantified mRNA and non-coding RNA (ncRNA) expression profiles by RNA-seq, microarray analysis and small ncRNA sequencing technology in the CA1 region of the hippocampus. Hippocampal slice immunohistochemistry was used to determine CPF-induced changes in protein expression and localization patterns. Neither dose of CPF caused overt clinical signs of cholinergic toxicity, although after 21 days of exposure, cholinesterase activity was decreased to 58% or 13% of control levels in the hippocampus of rats in the 3 or 10mg/kg/d groups, respectively. Differential gene expression in the CA1 region of the hippocampus was observed only in the 10mg/kg/d dose group relative to controls. Of the 1382 differentially expressed genes identified by RNA-seq and microarray analysis, 67 were common to both approaches. Differential expression of six of these genes (Bdnf, Cort, Crhbp, Nptx2, Npy and Pnoc) was verified in an independent CPF exposure study; immunohistochemistry demonstrated that CRHBP and NPY were elevated in the CA1 region of the hippocampus at 10mg/kg/d CPF. Gene ontology enrichment analysis suggested association of these genes with receptor-mediated cell survival signaling pathways. miR132/212 was also elevated in the CA1 hippocampal region, which may play a role in the disruption of neurotrophin-mediated cognitive processes after CPF administration. These findings identify potential mediators of CPF-induced neurobehavioral deficits following subchronic exposure to CPF at

  14. Advanced age, altered level of consciousness and a new diagnosis of diabetes are independently associated with hypernatreamia in hyperglycaemic crisis

    Directory of Open Access Journals (Sweden)

    Ogbera Anthonia O


    Full Text Available Abstract Background There is limited literature on hypernatreamia in the setting of hyperglycaemic crisis. This is despite the fact that the presence of hypernatreamia may impact on the classification of hyperglycaemic crisis and its management particularly with regards to the nature of fluid therapy. We determined the prevalence of hypernatreamia and its associated factors at presentation for hyperglycaemic crisis. Methods This was a retrospective review of data for hyperglycaemic crisis admissions in Nelson Mandela Academic Hospital, Mthatha, South Africa. The prevalence of hypernatreamia (uncorrected Serum Sodium at presentation >145 mmol/L was determined. Hyperosmolality was defined by calculated effective osmolality >320 mosmols/Kg. Multivariate logistic regression was undertaken using variables that were statistically significant in univariate analysis to ascertain those that were independently associated (Odds Ratio (OR with 95% Confidence Interval (CI with hypernatreamia. Results The prevalence of hypernatreamia in our admissions for hyperglycaemic crisis was 11.7% (n = 32/273 including 171 females and 102 males. All admissions with hypernatreamia met the criteria for hyperosmolality. Age ≥ 60 years (OR = 3.9 95% CI 1.3-12.3; P = 0.018, Altered level of consciousness (OR = 8.8 95% CI 2.3-32.8; P Conclusion The prevalence rate of hypernatreamia in hyperglycaemic admissions was high with all hypernatreamic admissions meeting the criteria for hyperosmolality. Advanced age, altered conscious level and a new diagnosis of diabetes were independently associated with hypernatreamia.

  15. Lack of Platelet-Activating Factor Receptor Attenuates Experimental Food Allergy but Not Its Metabolic Alterations regarding Adipokine Levels (United States)

    Batista, Nathália Vieira; Fonseca, Roberta Cristelli; Perez, Denise; Pereira, Rafaela Vaz Sousa; de Lima Alves, Juliana; Pinho, Vanessa; Faria, Ana Maria Caetano; Cara, Denise Carmona


    Platelet-activating factor (PAF) is known to be an important mediator of anaphylaxis. However, there is a lack of information in the literature about the role of PAF in food allergy. The aim of this work was to elucidate the participation of PAF during food allergy development and the consequent adipose tissue inflammation along with its alterations. Our data demonstrated that, both before oral challenge and after 7 days receiving ovalbumin (OVA) diet, OVA-sensitized mice lacking the PAF receptor (PAFR) showed a decreased level of anti-OVA IgE associated with attenuated allergic markers in comparison to wild type (WT) mice. Moreover, there was less body weight and adipose tissue loss in PAFR-deficient mice. However, some features of inflamed adipose tissue presented by sensitized PAFR-deficient and WT mice after oral challenge were similar, such as a higher rate of rolling leukocytes in this tissue and lower circulating levels of adipokines (resistin and adiponectin) in comparison to nonsensitized mice. Therefore, PAF signaling through PAFR is important for the allergic response to OVA but not for the adipokine alterations caused by this inflammatory process. Our work clarifies some effects of PAF during food allergy along with its role on the metabolic consequences of this inflammatory process. PMID:27314042

  16. Minocycline treatment inhibits microglial activation and alters spinal levels of endocannabinoids in a rat model of neuropathic pain. (United States)

    Guasti, Leonardo; Richardson, Denise; Jhaveri, Maulik; Eldeeb, Khalil; Barrett, David; Elphick, Maurice R; Alexander, Stephen P H; Kendall, David; Michael, Gregory J; Chapman, Victoria


    Activation of spinal microglia contributes to aberrant pain responses associated with neuropathic pain states. Endocannabinoids (ECs) are present in the spinal cord, and inhibit nociceptive processing; levels of ECs may be altered by microglia which modulate the turnover of endocannabinoids in vitro. Here, we investigate the effect of minocycline, an inhibitor of activated microglia, on levels of the endocannabinoids anandamide and 2-arachidonoylglycerol (2-AG), and the related compound N-palmitoylethanolamine (PEA), in neuropathic spinal cord. Selective spinal nerve ligation (SNL) in rats resulted in mechanical allodynia and the presence of activated microglia in the ipsilateral spinal cord. Chronic daily treatment with minocycline (30 mg/kg, ip for 14 days) significantly reduced the development of mechanical allodynia at days 5, 10 and 14 post-SNL surgery, compared to vehicle-treated SNL rats (P pain states.

  17. Minocycline treatment inhibits microglial activation and alters spinal levels of endocannabinoids in a rat model of neuropathic pain

    Directory of Open Access Journals (Sweden)

    Elphick Maurice R


    Full Text Available Abstract Activation of spinal microglia contributes to aberrant pain responses associated with neuropathic pain states. Endocannabinoids (ECs are present in the spinal cord, and inhibit nociceptive processing; levels of ECs may be altered by microglia which modulate the turnover of endocannabinoids in vitro. Here, we investigate the effect of minocycline, an inhibitor of activated microglia, on levels of the endocannabinoids anandamide and 2-arachidonoylglycerol (2-AG, and the related compound N-palmitoylethanolamine (PEA, in neuropathic spinal cord. Selective spinal nerve ligation (SNL in rats resulted in mechanical allodynia and the presence of activated microglia in the ipsilateral spinal cord. Chronic daily treatment with minocycline (30 mg/kg, ip for 14 days significantly reduced the development of mechanical allodynia at days 5, 10 and 14 post-SNL surgery, compared to vehicle-treated SNL rats (P P P P P

  18. Actions of agonists, fipronil and ivermectin on the predominant in vivo splice and edit variant (RDLbd, I/V of the Drosophila GABA receptor expressed in Xenopus laevis oocytes.

    Directory of Open Access Journals (Sweden)

    Kristin Lees

    Full Text Available Ionotropic GABA receptors are the targets for several classes of insecticides. One of the most widely-studied insect GABA receptors is RDL (resistance to dieldrin, originally isolated from Drosophila melanogaster. RDL undergoes alternative splicing and RNA editing, which influence the potency of GABA. Most work has focussed on minority isoforms. Here, we report the first characterisation of the predominant native splice variant and RNA edit, combining functional characterisation with molecular modelling of the agonist-binding region. The relative order of agonist potency is GABA> muscimol> TACA> β-alanine. The I/V edit does not alter the potency of GABA compared to RDLbd. Docking calculations suggest that these agonists bind and activate RDLbdI/V through a similar binding mode. TACA and β-alanine are predicted to bind with lower affinity than GABA, potentially explaining their lower potency, whereas the lower potency of muscimol and isoguvacine cannot be explained structurally from the docking calculations. The A301S (resistance to dieldrin mutation reduced the potency of antagonists picrotoxin, fipronil and pyrafluprole but the I/V edit had no measurable effect. Ivermectin suppressed responses to GABA of RDLbdI/V, RDLbd and RDLbdI/VA301S. The dieldrin resistant variant also showed reduced sensitivity to Ivermectin. This study of a highly abundant insect GABA receptor isoform will help the design of new insecticides.

  19. Neurobeachin Regulates Glutamate- and GABA-Receptor Targeting to Synapses via Distinct Pathways. (United States)

    Farzana, F; Zalm, R; Chen, N; Li, K W; Grant, Seth G N; Smit, A B; Toonen, R F; Verhage, M


    Neurotransmission and synaptic strength depend on expression of post-synaptic receptors on the cell surface. Post-translational modification of receptors, trafficking to the synapse through the secretory pathway, and subsequent insertion into the synapse involves interaction of the receptor with A-kinase anchor proteins (AKAPs) and scaffolding proteins. Neurobeachin (Nbea), a brain specific AKAP, is required for synaptic surface expression of both glutamate and GABA receptors. Here, we investigated the role of Nbea-dependent targeting of postsynaptic receptors by studying Nbea interaction with synapse-associated protein 102 (SAP102/Dlg3) and protein kinase A subunit II (PKA II). A Nbea mutant lacking the PKA binding domain showed a similar distribution as wild-type Nbea in Nbea null neurons and partially restored GABA receptor surface expression. To understand the relevance of Nbea interaction with SAP102, we analysed SAP102 null mutant mice. Nbea levels were reduced by ~80% in SAP102 null mice, but glutamatergic receptor expression was normal. A single-point mutation in the pleckstrin homology domain of Nbea (E2218R) resulted in loss of binding with SAP102. When expressed in Nbea null neurons, this mutant fully restored GABA receptor surface expression, but not glutamate receptor expression. Our results suggest that the PKA-binding domain is not essential for Nbea's role in receptor targeting and that Nbea targets glutamate and GABA receptors to the synapse via distinct molecular pathways by interacting with specific effector proteins.

  20. Modulation of glucose transporter 1 (GLUT1 expression levels alters mouse mammary tumor cell growth in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Christian D Young

    Full Text Available Tumor cells exhibit an altered metabolism characterized by elevated aerobic glycolysis and lactate secretion which is supported by an increase in glucose transport and consumption. We hypothesized that reducing or eliminating the expression of the most prominently expressed glucose transporter(s would decrease the amount of glucose available to breast cancer cells thereby decreasing their metabolic capacity and proliferative potential.Of the 12 GLUT family glucose transporters expressed in mice, GLUT1 was the most abundantly expressed at the RNA level in the mouse mammary tumors from MMTV-c-ErbB2 mice and cell lines examined. Reducing GLUT1 expression in mouse mammary tumor cell lines using shRNA or Cre/Lox technology reduced glucose transport, glucose consumption, lactate secretion and lipid synthesis in vitro without altering the concentration of ATP, as well as reduced growth on plastic and in soft agar. The growth of tumor cells with reduced GLUT1 expression was impaired when transplanted into the mammary fat pad of athymic nude mice in vivo. Overexpression of GLUT1 in a cell line with low levels of endogenous GLUT1 increased glucose transport in vitro and enhanced growth in nude mice in vivo as compared to the control cells with very low levels of GLUT1.These studies demonstrate that GLUT1 is the major glucose transporter in mouse mammary carcinoma models overexpressing ErbB2 or PyVMT and that modulation of the level of GLUT1 has an effect upon the growth of mouse mammary tumor cell lines in vivo.

  1. Activation of vagus nerve by semapimod alters substance P levels and decreases breast cancer metastasis. (United States)

    Erin, Nuray; Duymuş, Ozlem; Oztürk, Saffet; Demir, Necdet


    Chronic inflammation is involved in initiation as well as in progression of cancer. Semapimod, a tetravalent guanylhydrazon and formerly known as CNI-1493, inhibits the release of inflammatory cytokines from activated macrophages and this effect is partly mediated by the vagus nerve. Our previous findings demonstrated that inactivation of vagus nerve activity as well sensory neurons enhanced visceral metastasis of 4THM breast carcinoma. Hence semapimod by activating vagus nerve may inhibit breast cancer metastasis. Here, effects of semapimod on breast cancer metastasis, the role of vagal sensory neurons on this effect and changes in mediators of the neuroimmune connection, such as substance P (SP) as well as neprilysin-like activity, were examined. Vagotomy was performed on half of the control animals that were treated with semapimod following orthotopic injection of 4THM breast carcinoma cells. Semapimod decreased lung and liver metastases in control but not in vagotomized animals with an associated increased SP levels in sensory nerve endings. Semapimod also increased neprilysin-like activity in lung tissue of control animals but not in tumor-bearing animals. This is the first report demonstrating that semapimod enhances vagal sensory nerve activity and may have anti-tumoral effects under in-vivo conditions. Further studies, however, are required to elucidate the conditions and the mechanisms involved in anti-tumoral effects of semapimod.

  2. Alteration of brain levels of neurotransmitters and amino acids in male F344 rats induced by three-week repeated inhalation exposure to 1-bromopropane. (United States)

    Suda, Megumi; Honma, Takeshi; Miyagawa, Muneyuki; Wang, Rui-Sheng


    The present study investigated the effects of 1-bromopropane (1BP) on brain neuroactive substances of rats to determine the extent of its toxicity to the central nervous system (CNS). We measured the changes in neurotransmitters (acetylcholine, catecholamine, serotonin and amino acids) and their metabolites or precursors in eight brain regions after inhalation exposure to 1BP at 50 to 1,000 ppm for 8 h per day for 7 d per week for 3 wk. Rats were sacrificed at 2 h (Case 1), or at 19 h (Case 2) after the end of exposure. In Case 1, the level of 5-hydroxyindoleacetic acid (5HIAA) was lowered in some brain regions by 1BP exposure. The decrease of 5HIAA in the frontal cortex was statistically significant at 50 ppm 1BP exposure. In Case 2, gamma-amino butyric acid (GABA) and taurine were decreased in many brain regions of exposed rats, and a significant decrease of taurine in the midbrain occurred at 50 ppm 1BP exposure. In both cases of 2-h and 19-h intervals from the end of exposure to sacrifice, aspartate and glutamine levels were elevated in many brain regions, but the acetylcholine level did not change in any brain region. Three-week repeated exposure to 1BP produced significantly changes in amino acid contents of rat brains, particularly at 1,000 ppm.

  3. Wastewater treatment plant effluent alters pituitary gland gonadotropin mRNA levels in juvenile coho salmon (Oncorhynchus kisutch). (United States)

    Harding, Louisa B; Schultz, Irvin R; da Silva, Denis A M; Ylitalo, Gina M; Ragsdale, Dave; Harris, Stephanie I; Bailey, Stephanie; Pepich, Barry V; Swanson, Penny


    It is well known that endocrine disrupting compounds (EDCs) present in wastewater treatment plant (WWTP) effluents interfere with reproduction in fish, including altered gonad development and induction of vitellogenin (Vtg), a female-specific egg yolk protein precursor produced in the liver. As a result, studies have focused on the effects of EDC exposure on the gonad and liver. However, impacts of environmental EDC exposure at higher levels of the hypothalamic-pituitary-gonad axis are less well understood. The pituitary gonadotropins, follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh) are involved in all aspects of gonad development and are subject to feedback from gonadal steroids making them a likely target of endocrine disruption. In this study, the effects of WWTP effluent exposure on pituitary gonadotropin mRNA expression were investigated to assess the utility of Lh beta-subunit (lhb) as a biomarker of estrogen exposure in juvenile coho salmon (Oncorhynchus kisutch). First, a controlled 72-h exposure to 17α-ethynylestradiol (EE2) and 17β-trenbolone (TREN) was performed to evaluate the response of juvenile coho salmon to EDC exposure. Second, juvenile coho salmon were exposed to 0, 20 or 100% effluent from eight WWTPs from the Puget Sound, WA region for 72h. Juvenile coho salmon exposed to 2 and 10ng EE2L(-1) had 17-fold and 215-fold higher lhb mRNA levels relative to control fish. Hepatic vtg mRNA levels were dramatically increased 6670-fold, but only in response to 10ng EE2L(-1) and Fsh beta-subunit (fshb) mRNA levels were not altered by any of the treatments. In the WWTP effluent exposures, lhb mRNA levels were significantly elevated in fish exposed to five of the WWTP effluents. In contrast, transcript levels of vtg were not affected by any of the WWTP effluent exposures. Mean levels of natural and synthetic estrogens in fish bile were consistent with pituitary lhb expression, suggesting that the observed lhb induction may be due to

  4. Dorsomedial hypothalamic GABA regulates anxiety in the social interaction test. (United States)

    Shekhar, A; Katner, J S


    Blockade of GABAA function in the region of the dorsomedial hypothalamus (DMH) of rats is known to elicit a constellation of physiologic responses including increases in heart rate (HR), mean arterial blood pressure (BP), respiratory rate, and plasma catecholamine levels, as well as behavioral responses such as increases in locomotor activity and anxiogenic-like effects as measured in a conflict test and the elevated plus-maze test. The aim of the present study was to test the effects of microinjecting GABAA antagonists bicuculline methiodide (BMI) and picrotoxin, as well as the GABAA agonist muscimol, into the DMH of rats placed in the social interaction (SI) test. Muscimol decreased HR and BP but increased SI, whereas the GABA antagonists increased HR and BP but decreased SI time. Blocking the HR changes elicited by GABAergic drugs injected into the DMH with systemic injections of atenolol and atropine methylbromide did not block their effects on SI.

  5. GABA transporter subtype 1 and GABA transporter subtype 3 modulate glutamatergic transmission via activation of presynaptic GABA(B) receptors in the rat globus pallidus. (United States)

    Jin, Xiao-Tao; Paré, Jean-Francois; Smith, Yoland


    The intra-pallidal application of γ-aminobutyric acid (GABA) transporter subtype 1 (GAT-1) or GABA transporter subtype 3 (GAT-3) transporter blockers [1-(4,4-diphenyl-3-butenyl)-3-piperidinecarboxylic acid hydrochloride (SKF 89976A) or 1-[2-[tris(4-methoxyphenyl)methoxy]ethyl]-(S)-3-piperidinecarboxylic acid (SNAP 5114)] reduces the activity of pallidal neurons in monkey. This effect could be mediated through the activation of presynaptic GABA(B) heteroreceptors in glutamatergic terminals by GABA spillover following GABA transporter (GAT) blockade. To test this hypothesis, we applied the whole-cell recording technique to study the effects of SKF 89976A and SNAP 5114 on evoked excitatory postsynaptic currents (eEPSCs) in the presence of gabazine, a GABA(A) receptor antagonist, in rat globus pallidus slice preparations. Under the condition of postsynaptic GABA(B) receptor blockade by the intra-cellular application of N-(2,6-dimethylphenylcarbamoylmethyl)-triethylammonium bromide (OX314), bath application of SKF 89976A (10 μM) or SNAP 5114 (10 μM) decreased the amplitude of eEPSCs, without a significant effect on its holding current and whole cell input resistance. The inhibitory effect of GAT blockade on eEPSCs was blocked by (2S)-3-[[(1S)-1-(3,4-dichlorophenyl)ethyl]amino-2-hydroxypropyl](phenylmethyl)phosphinic acid, a GABA(B) receptor antagonist. The paired-pulse ratio of eEPSCs was increased, whereas the frequency, but not the amplitude, of miniature excitatory postsynaptic currents was reduced in the presence of either GAT blocker, demonstrating a presynaptic effect. These results suggest that synaptically released GABA can inhibit glutamatergic transmission through the activation of presynaptic GABA(B) heteroreceptors following GAT-1 or GAT-3 blockade. In conclusion, our findings demonstrate that presynaptic GABA(B) heteroreceptors in putative glutamatergic subthalamic afferents to the globus pallidus are sensitive to increases in extracellular GABA induced

  6. Altered Levels of Aroma and Volatiles by Metabolic Engineering of Shikimate Pathway Genes in Tomato Fruits

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    Vered Tzin


    Full Text Available The tomato (Solanum lycopersicum fruit is an excellent source of antioxidants, dietary fibers, minerals and vitamins and therefore has been referred to as a “functional food”. Ripe tomato fruits produce a large number of specialized metabolites including volatile organic compounds. These volatiles serve as key components of the tomato fruit flavor, participate in plant pathogen and herbivore defense, and are used to attract seed dispersers. A major class of specialized metabolites is derived from the shikimate pathway followed by aromatic amino acid biosynthesis of phenylalanine, tyrosine and tryptophan. We attempted to modify tomato fruit flavor by overexpressing key regulatory genes in the shikimate pathway. Bacterial genes encoding feedback-insensitive variants of 3-Deoxy-D-Arabino-Heptulosonate 7-Phosphate Synthase (DAHPS; AroG209-9 and bi-functional Chorismate Mutase/Prephenate Dehydratase (CM/PDT; PheA12 were expressed under the control of a fruit-specific promoter. We crossed these transgenes to generate tomato plants expressing both the AroG209 and PheA12 genes. Overexpression of the AroG209-9 gene had a dramatic effect on the overall metabolic profile of the fruit, including enhanced levels of multiple volatile and non-volatile metabolites. In contrast, the PheA12 overexpression line exhibited minor metabolic effects compared to the wild type fruit. Co-expression of both the AroG209-9 and PheA12 genes in tomato resulted overall in a similar metabolic effect to that of expressing only the AroG209-9 gene. However, the aroma ranking attributes of the tomato fruits from PheA12//AroG209-9 were unique and different from those of the lines expressing a single gene, suggesting a contribution of the PheA12 gene to the overall metabolic profile. We suggest that expression of bacterial genes encoding feedback-insensitive enzymes of the shikimate pathway in tomato fruits provides a useful metabolic engineering tool for the modification of

  7. Manganese accumulation in membrane fractions of primary astrocytes is associated with decreased γ-aminobutyric acid (GABA) uptake, and is exacerbated by oleic acid and palmitate. (United States)

    Fordahl, Steve C; Erikson, Keith M


    Manganese (Mn) exposure interferes with GABA uptake; however, the effects of Mn on GABA transport proteins (GATs) have not been identified. We sought to characterize how Mn impairs GAT function in primary rat astrocytes. Astrocytes exposed to Mn (500 μM) had significantly reduced (3)H-GABA uptake despite no change in membrane or cytosolic GAT3 protein levels. Co-treatment with 100 μM oleic or palmitic acids (both known to be elevated in Mn neurotoxicity), exacerbated the Mn-induced decline in (3)H-GABA uptake. Mn accumulation in the membrane fraction of astrocytes was enhanced with fatty acid administration, and was negatively correlated with (3)H-GABA uptake. Furthermore, control cells exposed to Mn only during the experimental uptake had significantly reduced (3)H-GABA uptake, and the addition of GABA (50 μM) blunted cytosolic Mn accumulation. These data indicate that reduced GAT function in astrocytes is influenced by Mn and fatty acids accumulating at or interacting with the plasma membrane.

  8. Altered Brain Network in Amyotrophic Lateral Sclerosis: A Resting Graph Theory-Based Network Study at Voxel-Wise Level. (United States)

    Zhou, Chaoyang; Hu, Xiaofei; Hu, Jun; Liang, Minglong; Yin, Xuntao; Chen, Lin; Zhang, Jiuquan; Wang, Jian


    Amyotrophic lateral sclerosis (ALS) is a rare degenerative disorder characterized by loss of upper and lower motor neurons. Neuroimaging has provided noticeable evidence that ALS is a complex disease, and shown that anatomical and functional lesions extend beyond precentral cortices and corticospinal tracts, to include the corpus callosum; frontal, sensory, and premotor cortices; thalamus; and midbrain. The aim of this study is to investigate graph theory-based functional network abnormalities at voxel-wise level in ALS patients on a whole brain scale. Forty-three ALS patients and 44 age- and sex-matched healthy volunteers were enrolled. The voxel-wise network degree centrality (DC), a commonly employed graph-based measure of network organization, was used to characterize the alteration of whole brain functional network. Compared with the controls, the ALS patients showed significant increase of DC in the left cerebellum posterior lobes, bilateral cerebellum crus, bilateral occipital poles, right orbital frontal lobe, and bilateral prefrontal lobes; significant decrease of DC in the bilateral primary motor cortex, bilateral sensory motor region, right prefrontal lobe, left bilateral precuneus, bilateral lateral temporal lobes, left cingulate cortex, and bilateral visual processing cortex. The DC's z-scores of right inferior occipital gyrus were significant negative correlated with the ALSFRS-r scores. Our findings confirm that the regions with abnormal network DC in ALS patients were located in multiple brain regions including primary motor, somatosensory and extra-motor areas, supporting the concept that ALS is a multisystem disorder. Specifically, our study found that DC in the visual areas was altered and ALS patients with higher DC in right inferior occipital gyrus have more severity of disease. The result demonstrated that the altered DC value in this region can probably be used to assess severity of ALS.

  9. Mutants of GABA transaminase (POP2 suppress the severe phenotype of succinic semialdehyde dehydrogenase (ssadh mutants in Arabidopsis.

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    Frank Ludewig

    Full Text Available BACKGROUND: The gamma-aminubutyrate (GABA shunt bypasses two steps of the tricarboxylic acid cycle, and is present in both prokaryotes and eukaryotes. In plants, the pathway is composed of the calcium/calmodulin-regulated cytosolic enzyme glutamate decarboxylase (GAD, the mitochondrial enzymes GABA transaminase (GABA-T; POP2 and succinic semialdehyde dehydrogenase (SSADH. We have previously shown that compromising the function of the GABA-shunt, by disrupting the SSADH gene of Arabidopsis, causes enhanced accumulation of reactive oxygen intermediates (ROIs and cell death in response to light and heat stress. However, to date, genetic investigations of the relationships between enzymes of the GABA shunt have not been reported. PRINCIPAL FINDINGS: To elucidate the role of succinic semialdehyde (SSA, gamma-hydroxybutyrate (GHB and GABA in the accumulation of ROIs, we combined two genetic approaches to suppress the severe phenotype of ssadh mutants. Analysis of double pop2 ssadh mutants revealed that pop2 is epistatic to ssadh. Moreover, we isolated EMS-generated mutants suppressing the phenotype of ssadh revealing two new pop2 alleles. By measuring thermoluminescence at high temperature, the peroxide contents of ssadh and pop2 mutants were evaluated, showing that only ssadh plants accumulate peroxides. In addition, pop2 ssadh seedlings are more sensitive to exogenous SSA or GHB relative to wild type, because GHB and/or SSA accumulate in these plants. SIGNIFICANCE: We conclude that the lack of supply of succinate and NADH to the TCA cycle is not responsible for the oxidative stress and growth retardations of ssadh mutants. Rather, we suggest that the accumulation of SSA, GHB, or both, produced downstream of the GABA-T transamination step, is toxic to the plants, resulting in high ROI levels and impaired development.

  10. GABA shunt enzymes and the relationship with morphine abstinence

    NARCIS (Netherlands)

    Th. de Boer (Thijs)


    textabstractSelective inhibition of tbe rate-limiting step in tbe degradation of tbe inhibitory neurotransmitter Y·aminobutyric acid (GABA) might be of potential use in the treatment of many neurological or psychiatric disorders since it might correct a central GABA deficiency. Alternatively, as suc

  11. Association of urinary metal profiles with altered glucose levels and diabetes risk: a population-based study in China.

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    Wei Feng

    Full Text Available Elevated heavy metals and fasting plasma glucose (FPG levels were both associated with increased risk of cardiovascular diseases. However, studies on the associations of heavy metals and essential elements with altered FPG and diabetes risk were limited or conflicting. The objective of this study was to evaluate the potential associations of heavy metals and essential trace elements with FPG and diabetes risk among general Chinese population.We conducted a cross-sectional study to investigate the associations of urinary concentrations of 23 metals with FPG, impaired fasting glucose (IFG and diabetes among 2242 community-based Chinese adults in Wuhan. We used the false discovery rate (FDR method to correct for multiple hypothesis tests.After adjusting for potential confounders, urinary aluminum, titanium, cobalt, nickel, copper, zinc, selenium, rubidium, strontium, molybdenum, cadmium, antimony, barium, tungsten and lead were associated with altered FPG, IFG or diabetes risk (all P< 0.05; arsenic was only dose-dependently related to diabetes (P< 0.05. After additional adjustment for multiple testing, titanium, copper, zinc, selenium, rubidium, tungsten and lead were still significantly associated with one or more outcomes (all FDR-adjusted P< 0.05.Our results suggest that multiple metals in urine are associated with FPG, IFG or diabetes risk. Because the cross-sectional design precludes inferences about causality, further prospective studies are warranted to validate our findings.

  12. Drospirenone intake alters plasmatic steroid levels and cyp17a1 expression in gonads of juvenile sea bass. (United States)

    Blanco, Maria; Fernandes, Denise; Medina, Paula; Blázquez, Mercedes; Porte, Cinta


    Drospirenone (DRO) is one of the most widely used progestins in contraceptive treatments and hormone replacement therapies. The pharmacokinetics and potential toxicological effects of DRO were investigated in juvenile sea bass (Dicentrarchus labrax) exposed through the diet (0.01-10 μg DRO/g) for up to 31 days. DRO was detected in the blood (4-27 ng/mL) of fish exposed to the highest concentration, with no significant bioaccumulation over time and no alteration of hepatic metabolizing enzymes, namely, CYP1A and CYP3A-catalysed activities and UDP-glucuronyltransferase (UGT). Pregnenolone (P5), progesterone (P4), 17α-hydroxyprogesterone (17P4), 17α-hydroxypregnenolone (17P5), androstenedione (AD) and testosterone (T) were determined in plasma and gene expression of cyp17a1, cyp19a1a and cyp11β analysed by qRT-PCR in gonads. The significant increase in plasmatic levels of 17P5, 17P4 and AD detected after 31 days exposure to 10 ng DRO/g together with the increased expression of cyp17a1 in females evidence the ability of DRO to alter steroid synthesis at low intake concentrations (7 ng DRO/day). However, the potential consequences of this steroid shift for female reproduction remain to be investigated.

  13. Recombinant Human Leptin Does Not Alter Gut Hormone Levels after Gastric Bypass but May Attenuate Sweet Cravings

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    Rushika Conroy


    Full Text Available Bariatric surgery improves glucose homeostasis and alters gut hormones partly independent of weight loss. Leptin plays a role in these processes; levels are decreased following bariatric surgery, creating a relative leptin insufficiency. We previously showed that leptin administration in a weight-reduced state after Roux-en-Y gastric bypass (RYGB caused no further weight loss. Here, we discuss the impact of leptin administration on gut hormones, glucostasis, and appetite. Weight stable women after RYGB were randomized to receive placebo or recombinant human metreleptin (0.05 mg/kg twice daily. At weeks 0 and 16, a liquid meal challenge was performed. Glucose, insulin, C-peptide, GLP-1, PYY, glucagon, and ghrelin (total, acyl, and desacyl were measured fasting and postprandially. Appetite was assessed using a visual analog scale. Mean post-op period was 53±2.3 months; mean BMI was 34.6±0.2 kg/m2. At 16 weeks, there was no significant change in weight within or between groups. Fasting PYY was significantly different between groups and the leptin group had lower sweets craving at week 16 than the placebo group (P<0.05. No other differences were observed. Leptin replacement does not alter gut hormones or glucostasis but may diminish sweet cravings compared to placebo in this population of post-RYGB women.

  14. Rhythmic and dysrhythmic thalamocortical dynamics: GABA systems and the edge effect. (United States)

    Llinás, Rodolfo; Urbano, Francisco J; Leznik, Elena; Ramírez, Rey R; van Marle, Hein J F


    Brain function is fundamentally related in the most general sense to the richness of thalamocortical interconnectivity, and in particular to the rhythmic oscillatory properties of thalamocortical loops. Such rhythmicity is involved in the genesis of cognition, in the sleep-wake cycle, and in several neurological and psychiatric disorders. The role of GABA-mediated transmission in regulating these functional states is addressed here. At the cortical level, inhibition determines the spread of cortical activation by sculpting the precise activity patterns that underlie the details of cognition and motor control. At the thalamic level, GABA-mediated inhibition modulates and resets distribution of the ongoing thalamocortical rhythmic oscillations that bind multisensory inputs into a single cognitive experience and regulate arousal levels.

  15. A noncanonical release of GABA and glutamate modulates neuronal migration. (United States)

    Manent, Jean-Bernard; Demarque, Michaël; Jorquera, Isabel; Pellegrino, Christophe; Ben-Ari, Yehezkel; Aniksztejn, Laurent; Represa, Alfonso


    Immature neurons express GABA and glutamate receptors before synapse formation, and both transmitters are released at an early developmental stage. We have now tested the hypothesis that the ongoing release of GABA and glutamate modulates neuronal migration. Using 5-bromo-2'-deoxyuridine labeling and cocultures of hippocampal slices obtained from naive and green fluorescent protein-transgenic mice, we report that migration is severely affected by GABA(A) or NMDA receptor antagonist treatments. These effects were also present in munc18-1 knock-out slices in which soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-dependent vesicular secretion of transmitters has been deleted. GABA(A) antagonists were more efficient than NMDA antagonists to reduce cell migration, in keeping with the earlier maturation of GABAergic mechanisms. We conclude that GABA and, to a lesser degree, glutamate released in a SNARE-independent mechanism exert a paracrine action on neuronal migration.

  16. Periodontitis increases rheumatic factor serum levels and citrullinated proteins in gingival tissues and alter cytokine balance in arthritic rats (United States)

    Corrêa, Mônica G.; Sacchetti, Silvana B.; Ribeiro, Fernanda Vieira; Pimentel, Suzana Peres; Casarin, Renato Corrêa Viana; Cirano, Fabiano Ribeiro; Casati, Marcio Z.


    This study investigated some immunological features by experimental periodontitis (EP) and rheumatoid arthritis (RA) disease interact in destructive processes in arthritic rats. Rats were assigned to the following groups: EP +RA; RA; EP; and Negative Control. RA was induced by immunizations with type-II collagen and a local immunization with Complete Freund’s adjuvant in the paw. Periodontitis was induced by ligating the right first molars. The serum level of rheumatoid factor (RF) and anti-citrullinated protein antibody (ACCPA) were measured before the induction of EP (T1) and at 28 days after (T2) by ELISA assay. ACCPA levels were also measured in the gingival tissue at T2. The specimens were processed for morphometric analysis of bone loss, and the gingival tissue surrounding the first molar was collected for the quantification of interleukin IL-1β, IL-4, IL-6, IL-17 and TNF-α using a Luminex/MAGpix assay. Paw edema was analyzed using a plethysmometer. Periodontitis increased the RF and ACCPA levels in the serum and in the gingival tissue, respectively. Besides, the level of paw swelling was increased by EP and remained in progress until the end of the experiment, when EP was associated with RA. Greater values of IL-17 were observed only when RA was present, in spite of PE. It can be concluded that periodontitis increases rheumatic factor serum levels and citrullinated proteins level in gingival tissues and alter cytokine balance in arthritic rats; at the same time, arthritis increases periodontal destruction, confirming the bidirectional interaction between diseases. PMID:28358812

  17. Photoperiodic changes in endocannabinoid levels and energetic responses to altered signalling at CB1 receptors in Siberian hamsters. (United States)

    Ho, J M; Smith, N S; Adams, S A; Bradshaw, H B; Demas, G E


    Siberian hamsters (Phodopus sungorus) adapt to seasonal environmental conditions with marked changes in body mass, primarily in the form of adiposity. Winter-like conditions (e.g. short days) are sufficient to decrease body mass by approximately 30% in part via reductions in food intake. The neuroendocrine mechanisms responsible for these changes are not well understood, and homeostatic orexigenic/anorexigenic systems of the hypothalamus provide little explanation. We investigated the potential role of endocannabinoids, which are known modulators of appetite and metabolism, in mediating seasonal changes in energy balance. Specifically, we housed hamsters in long or short days for 0, 3, or 9 weeks and measured endocannabinoid levels in the hypothalamus, brainstem, liver and retroperitoneal white adipose tissue (RWAT). An additional group of males housed in short days for 25 weeks were also compared with long-day controls. Following 9 weeks in short days, levels of the endocannabinoid 2-arachidonoylglycerol (2-AG) were significantly elevated in RWAT and reduced in brainstem, although they returned to long-day levels by week 25 in short-day males that had cycled back to summer-like energy balance. Endocannabinoid levels in these tissues correlated significantly with adiposity and change in body mass. No photoperiodic changes were observed in the hypothalamus or liver; however, sex differences in 2-AG levels were found in the liver (males > females). We further tested the effects of CB(1) receptor signalling on ingestive behaviour. Five daily injections of CB(1) antagonist SR141716 significantly reduced food intake and body mass but not food hoarding. Although the CB(1) agonist arachidonyl-2-chloroethylamide did not appreciably affect either ingestive behaviour, body mass was significantly elevated following 2 days of injections. Taken altogether, these findings demonstrate that endocannabinoid levels vary with sex and photoperiod in a site-specific manner, and that

  18. In vivo molecular imaging of the GABA/benzodiazepine receptor complex in the aged rat brain. (United States)

    Hoekzema, Elseline; Rojas, Santiago; Herance, Raúl; Pareto, Deborah; Abad, Sergio; Jiménez, Xavier; Figueiras, Francisca P; Popota, Foteini; Ruiz, Alba; Flotats, Núria; Fernández, Francisco J; Rocha, Milagros; Rovira, Mariana; Víctor, Víctor M; Gispert, Juan D


    The GABA-ergic system, known to regulate neural tissue genesis during cortical development, has been postulated to play a role in cerebral aging processes. Using in vivo molecular imaging and voxel-wise quantification, we aimed to assess the effects of aging on the benzodiazepine (BDZ) recognition site of the GABA(A) receptor. To visualize BDZ site availability, [(11)C]-flumazenil microPET acquisitions were conducted in young and old rats. The data were analyzed and region of interest analyses were applied to validate the voxel-wise approach. We observed decreased [(11)C]-flumazenil binding in the aged rat brains in comparison with the young control group. More specifically, clusters of reduced radioligand uptake were detected in the bilateral hippocampus, cerebellum, midbrain, and bilateral frontal and parieto-occipital cortex. Our results support the pertinence of voxel-wise quantification in the analysis of microPET data. Moreover, these findings indicate that the aging process involves declines in neural BDZ recognition site availability, proposed to reflect alterations in GABA(A) receptor subunit polypeptide expression.

  19. Cocaine disinhibits dopamine neurons in the ventral tegmental area via use-dependent blockade of GABA neuron voltage-sensitive sodium channels. (United States)

    Steffensen, Scott C; Taylor, Seth R; Horton, Malia L; Barber, Elise N; Lyle, Laura T; Stobbs, Sarah H; Allison, David W


    The aim of this study was to evaluate the effects of cocaine on gamma-aminobutyric acid (GABA) and dopamine (DA) neurons in the ventral tegmental area (VTA). Utilizing single-unit recordings in vivo, microelectrophoretic administration of DA enhanced the firing rate of VTA GABA neurons via D2/D3 DA receptor activation. Lower doses of intravenous cocaine (0.25-0.5 mg/kg), or the DA transporter (DAT) blocker methamphetamine, enhanced VTA GABA neuron firing rate via D2/D3 receptor activation. Higher doses of cocaine (1.0-2.0 mg/kg) inhibited their firing rate, which was not sensitive to the D2/D3 antagonist eticlopride. The voltage-sensitive sodium channel (VSSC) blocker lidocaine inhibited the firing rate of VTA GABA neurons at all doses tested (0.25-2.0 mg/kg). Cocaine or lidocaine reduced VTA GABA neuron spike discharges induced by stimulation of the internal capsule (ICPSDs) at dose levels 0.25-2 mg/kg (IC(50) 1.2 mg/kg). There was no effect of DA or methamphetamine on ICPSDs, or of DA antagonists on cocaine inhibition of ICPSDs. In VTA GABA neurons in vitro, cocaine reduced (IC(50) 13 microm) current-evoked spikes and TTX-sensitive sodium currents in a use-dependent manner. In VTA DA neurons, cocaine reduced IPSCs (IC(50) 13 microm), increased IPSC paired-pulse facilitation and decreased spontaneous IPSC frequency, without affecting miniature IPSC frequency or amplitude. These findings suggest that cocaine acts on GABA neurons to reduce activity-dependent GABA release on DA neurons in the VTA, and that cocaine's use-dependent blockade of VTA GABA neuron VSSCs may synergize with its DAT inhibiting properties to enhance mesolimbic DA transmission implicated in cocaine reinforcement.

  20. Alterations in intracellular ionic calcium levels in isolated adult rat cardiac myocytes due to the generation of free radicals

    Energy Technology Data Exchange (ETDEWEB)

    Burton, K.P.; Nazeran, H.; Hagler, H.K. (Univ. of Texas, Dallas, TX (United States))


    Oxygen-derived free radical production has been documented to occur on reperfusion of the ischemic myocardium. Intracellular ionic calcium ((Ca{sup ++}){sub i}) levels in isolated adult rat cardiac myocytes (M) exposed to free radicals were evaluated using the fluorescent calcium indicator, fura-2. The effect of different time periods of free radical exposure and the level of extracellular Ca{sup ++} concentration on altering (Ca{sup ++}){sub i} was examined. The free radical generating system (FRGS) utilized consisted of a HEPES buffered physiological salt solution containing 2.3 mM purine, 2.4. {mu}M iron-loaded transferrin and 0.01 U/ml xanthine oxidase. M maintained in HEPES buffer or the HEPES buffer containing purine and iron-loaded transferrin continued to stimulate, exhibited relatively uniform 340/380 ratios and maintained a rod shape for extended time periods. M continuously exposed to the FRGS showed a significant increase in (Ca{sup ++}){sub i}, became unresponsive to stimulation at 31 {plus minus} 7 (SE) min and eventually exhibited contracture. Exposure to the FRGS for 10 min resulted in a response similar to continuous exposure. M exposed to the FRGS for 5 min exhibited regular Ca{sup ++} transients for 55{plus minus}5 min. M exposed to the FRGS for 10 min and maintained in 2.5 mM Ca{sup ++} versus 1.25 mM Ca{sup ++}, accumulated significantly higher (CA{sup ++}){sub i}. Quiescent myocytes continuously exposed to the FRGS also exhibited a significant increase in (Ca{sup ++}){sub i} over time. Thus, a brief period of free radical exposure may induce subsequent damage. Alterations in Ca{sup ++} flux resulting from the generation of free radicals may possibly contribute to the development of Ca{sup ++} overload and myocardial arrhythmias.

  1. Spinal Fluid Lactate Dehydrogenase Level Differentiates between Structural and Metabolic Etiologies of Altered Mental Status in Children

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    Full Text Available How to Cite This Article: Khosroshahi N, Alizadeh P, Khosravi M, Salamati P, Kamrani K. Spinal Fluid Lactate Dehydrogenase Level Differentiates between Structural and Metabolic Etiologies of Altered Mental Status in Children. Iran J Child Neurol. 2015 Winter;9(1:31-36.AbstractObjectiveAltered mental status is a common cause of intensive care unit admission inchildren. Differentiating structural causes of altered mental status from metabolic etiologies is of utmost importance in diagnostic approach and management of the patients. Among many biomarkers proposed to help stratifying patients with altered mental status, spinal fluid lactate dehydrogenase appears to be the most promising biomarker to predict cellular necrosis.Materials & MethodsIn this cross sectional study we measured spinal fluid level of lactatedehydrogenase in children 2 months to 12 years of age admitted to a single center intensive care unit over one year. Spinal fluid level of lactate dehydrogenase in 40 pediatric cases of febrile seizure was also determined as the control group.ResultsThe study group included 35 boys (58.3% and 25 girls (41.7%. Their meanage was 2.7+/-3 years and their mean spinal fluid lactate dehydrogenase levelwas 613.8+/-190.4 units/liter. The control group included 24 boys (55.8% and19 girls (44.2%. Their mean age was 1.3+/-1.2 years and their mean spinalfluid lactate dehydrogenase level was 18.9+/-7.5 units/liter. The mean spinalfluid lactate dehydrogenase level in children with abnormal head CT scan was246.3+/-351.5 units/liter compared to 164.5+/-705.7 in those with normal CTscan of the head (p=0.001.ConclusionSpinal fluid lactate dehydrogenase level is useful in differentiating structural andmetabolic causes of altered mental status in children. ReferencesFesk SK. Coma and confusional states: emergency diagnosis and management. Neurol Clin 1998; 16: 237- 56.Cucchiara BL, Kanser SE, Wolk DA, et al. Early impairment in consciousness Predicts

  2. GABA agonist promoted formation of low affinity GABA receptors on cerebellar granule cells is restricted to early development

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, G H; Schousboe, A;


    The ability of the GABA receptor agonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP) to promote formation of low affinity GABA receptors on cerebellar granule cells was tested using primary cultures of these neurons. Granule cells were exposed to THIP (150 microM) for 6 hr after......, respectively, 4, 7, 10 and 14 days in culture. It was found that THIP treatment of 4- and 7-day-old cultures led to formation of low affinity GABA receptors, whereas such receptors could not be detected after THIP treatment in the older cultures (10 and 14 days) in spite of the fact that these cultured granule...... cells expressed a high density of high affinity GABA receptors. It is concluded that the ability of THIP to promote formation of low affinity GABA receptors on cerebellar granule cells is restricted to an early developmental period....

  3. ToF-SIMS imaging of molecular-level alteration mechanisms in Le Bonheur de vivre by Henri Matisse

    Energy Technology Data Exchange (ETDEWEB)

    Voras, Zachary E.; Wiggins, Marcie B.; Beebe, Thomas P. [University of Delaware, Department of Chemistry and Biochemistry, Newark, DE (United States); University of Delaware, UD Surface Analysis Facility, Newark, DE (United States); DeGhetaldi, Kristin [University of Delaware, Department of Art Conservation, Newark, DE (United States); Winterthur-University of Delaware Program in Art Conservation, Winterthur, DE (United States); Buckley, Barbara [The Barnes Foundation, Department of Conservation, Philadelphia, PA (United States); Baade, Brian [University of Delaware, Department of Art Conservation, Newark, DE (United States); Mass, Jennifer L. [Winterthur Museum, Scientific Research and Analysis Laboratory, Conservation Department, Winterthur, DE (United States)


    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has recently been shown to be a valuable tool for cultural heritage studies, especially when used in conjunction with established analytical techniques in the field. The ability of ToF-SIMS to simultaneously image inorganic and organic species within a paint cross section at micrometer-level spatial resolution makes it a uniquely qualified analytical technique to aid in further understanding the processes of pigment and binder alteration, as well as pigment-binder interactions. In this study, ToF-SIMS was used to detect and image both molecular and elemental species related to CdS pigment and binding medium alteration on the painting Le Bonheur de vivre (1905-1906, The Barnes Foundation) by Henri Matisse. Three categories of inorganic and organic components were found throughout Le Bonheur de vivre and co-localized in cross-sectional samples using high spatial resolution ToF-SIMS analysis: (1) species relating to the preparation and photo-induced oxidation of CdS yellow pigments (2) varying amounts of long-chain fatty acids present in both the paint and primary ground layer and (3) specific amino acid fragments, possibly relating to the painting's complex restoration history. ToF-SIMS's ability to discern both organic and inorganic species via cross-sectional imaging was used to compare samples collected from Le Bonheur de vivre to artificially aged reference paints in an effort to gather mechanistic information relating to alteration processes that have been previously explored using μXANES, SR-μXRF, SEM-EDX, and SR-FTIR. The relatively high sensitivity offered by ToF-SIMS imaging coupled to the high spatial resolution allowed for the positive identification of degradation products (such as cadmium oxalate) in specific paint regions that have before been unobserved. The imaging of organic materials has provided an insight into the extent of destruction of the original binding medium, as well as

  4. Altered topological organization of high-level visual networks in Alzheimer's disease and mild cognitive impairment patients. (United States)

    Deng, Yanjia; Shi, Lin; Lei, Yi; Wang, Defeng


    Altered regional activation of high-level visual (HLV) cortices in patients with Alzheimer's disease (AD) or mild cognitive impairment (MCI) has been well documented in previous fMRI studies, which led us to investigate the underlying alteration of the HLV networks in the terms of intrinsic interaction and topological organization. First, the activation likelihood estimation, a coordinate-based meta-analysis approach, was used to define the cortical regions/nodes included in HLV networks of "what" and "where" visions. Secondly, the acquired HLV regions were used as seeds to calculate their interregional resting-state functional connectivities (RSFCs) based on the temporal correlation of rs-functional MRI (rs-fMRI) time series. Here, the rs-fMRI data of AD (n=30), late MCI (n=35), early MCI (n=52) and matched healthy controls (n=44) were obtained from the Alzheimer's Disease Neuroimaging Initiative dataset. Finally, based on the calculated pair-wise RSFCs, the "what" and "where" HLV networks were respectively constructed, and their topological properties were calculated and analyzed among groups using the graph theory method. The results demonstrated increased clustering coefficient combined with a prolonged characteristic path length of the "where" visual network in AD patients. No significant alternation of the "what" visual network was found among the groups. These results suggest that the abnormality of the HLV networks could be a late-stage outcome in AD and that the "where" visual network may be more susceptible to the AD-related neuropathological changes than the "what" visual network. In addition, the dysfunction of the "where" network is found to be characterized by a decreased integration combined with an increased local segregation.

  5. Projected near-future CO2 levels increase activity and alter defensive behaviours in the tropical squid Idiosepius pygmaeus

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    Blake L. Spady


    Full Text Available Carbon dioxide (CO2 levels projected to occur in the oceans by the end of this century cause a range of behavioural effects in fish, but whether other highly active marine organisms, such as cephalopods, are similarly affected is unknown. We tested the effects of projected future CO2 levels (626 and 956 µatm on the behaviour of male two-toned pygmy squid, Idiosepius pygmaeus. Exposure to elevated CO2 increased the number of active individuals by 19–25% and increased movement (number of line-crosses by nearly 3 times compared to squid at present-day CO2. Squid vigilance and defensive behaviours were also altered by elevated CO2 with >80% of individuals choosing jet escape responses over defensive arm postures in response to a visual startle stimulus, compared with 50% choosing jet escape responses at control CO2. In addition, more escape responses were chosen over threat behaviours in body pattern displays at elevated CO2 and individuals were more than twice as likely to use ink as a defence strategy at 956 µatm CO2, compared with controls. Increased activity could lead to adverse effects on energy budgets as well as increasing visibility to predators. A tendency to respond to a stimulus with escape behaviours could increase survival, but may also be energetically costly and could potentially lead to more chases by predators compared with individuals that use defensive postures. These results demonstrate that projected future ocean acidification affects the behaviours of a tropical squid species.

  6. Changes in Dietary Fat Content Rapidly Alters the Mouse Plasma Coagulation Profile without Affecting Relative Transcript Levels of Coagulation Factors.

    Directory of Open Access Journals (Sweden)

    Audrey C A Cleuren

    Full Text Available Obesity is associated with a hypercoagulable state and increased risk for thrombotic cardiovascular events.Establish the onset and reversibility of the hypercoagulable state during the development and regression of nutritionally-induced obesity in mice, and its relation to transcriptional changes and clearance rates of coagulation factors as well as its relation to changes in metabolic and inflammatory parameters.Male C57BL/6J mice were fed a low fat (10% kcal as fat; LFD or high fat diet (45% kcal as fat; HFD for 2, 4, 8 or 16 weeks. To study the effects of weight loss, mice were fed the HFD for 16 weeks and switched to the LFD for 1, 2 or 4 weeks. For each time point analyses of plasma and hepatic mRNA levels of coagulation factors were performed after overnight fasting, as well as measurements of circulating metabolic and inflammatory parameters. Furthermore, in vivo clearance rates of human factor (F VII, FVIII and FIX proteins were determined after 2 weeks of HFD-feeding.HFD feeding gradually increased the body and liver weight, which was accompanied by a significant increase in plasma glucose levels from 8 weeks onwards, while insulin levels were affected after 16 weeks. Besides a transient rise in cytokine levels at 2 weeks after starting the HFD, no significant effect on inflammation markers was present. Increased plasma levels of fibrinogen, FII, FVII, FVIII, FIX, FXI and FXII were observed in mice on a HFD for 2 weeks, which in general persisted throughout the 16 weeks of HFD-feeding. Interestingly, with the exception of FXI the effects on plasma coagulation levels were not paralleled by changes in relative transcript levels in the liver, nor by decreased clearance rates. Switching from HFD to LFD reversed the HFD-induced procoagulant shift in plasma, again not coinciding with transcriptional modulation.Changes in dietary fat content rapidly alter the mouse plasma coagulation profile, thereby preceding plasma metabolic changes, which

  7. Proton MRS of the unilateral substantia nigra in the human brain at 4 tesla: detection of high GABA concentrations. (United States)

    Oz, Gülin; Terpstra, Melissa; Tkác, Ivan; Aia, Pratibha; Lowary, Jodi; Tuite, Paul J; Gruetter, Rolf


    Parkinson's disease (PD) is characterized by loss of dopaminergic neurons in the substantia nigra (SN), the cause of which is unknown. Characterization of early SN pathology could prove beneficial in the treatment and diagnosis of PD. The present study shows that with the use of short-echo (5 ms) Stimulated-Echo Acquisition Mode (STEAM) spectroscopy and LCModel, a neurochemical profile consisting of 10 metabolites, including gamma-aminobutyric acid (GABA), glutamate (Glu), and glutathione (GSH), can be measured from the unilateral SN at 4 tesla. The neurochemical profile of the SN is unique and characterized by a fourfold higher GABA/Glu ratio compared to the cortex, in excellent agreement with established neurochemistry. The presence of elevated GABA levels in SN was validated with the use of editing, suggesting that partial volume effects were greatly reduced. These findings establish the feasibility of obtaining a neurochemical profile of the unilateral human SN by single-voxel spectroscopy in small volumes.

  8. Synthesis of neurotransmitter GABA via the neuronal tricarboxylic acid cycle is elevated in rats with liver cirrhosis consistent with a high GABAergic tone in chronic hepatic encephalopathy

    DEFF Research Database (Denmark)

    Leke, Renata; Bak, Lasse Kristoffer; Iversen, Peter


    J. Neurochem. (2011) 117, 824-832. ABSTRACT: Hepatic encephalopathy (HE) is a neuropsychiatric complication to liver disease. It is known that ammonia plays a role in the pathogenesis of HE and disturbances in the GABAergic system have been related to HE. Synthesis of GABA occurs by decarboxylation...... the neuronal tricarboxylic acid cycle, an energy-generating pathway, prior to being employed for GABA synthesis (the indirect pathway). We have previously shown that ammonia induces an elevation of the neuronal tricarboxylic acid cycle activity. Thus, the aims of the present study were to determine...... if increased levels of ammonia increase GABA synthesis via the indirect pathway in a rat model of HE induced by bile-duct ligation and in co-cultures of neurons and astrocytes exposed to ammonia. Employing (13) C-labeled precursors and subsequent analysis by mass spectrometry, we demonstrated that more GABA...

  9. Regulation of cognition and symptoms of psychosis: focus on GABA(A) receptors and glycine transporter 1. (United States)

    Möhler, Hanns; Rudolph, Uwe; Boison, Detlev; Singer, Philipp; Feldon, Joram; Yee, Benjamin K


    Adaptive purposeful behaviour depends on appropriate modifications of synaptic connectivity that incorporate an organism's past experience. At least some forms of such synaptic plasticity are believed to be mediated by NMDA receptors (NMDARs). Complementary interaction with inhibitory neurotransmission mediated by GABA(A) receptors, and upstream control of the excitability of NMDARs by glycine availability can greatly influence the efficacy of NMDAR mediated neuroplasticity, and thereby exert significant effects on cognition. Memory, selective attention or sensorimotor gating functions can be modified in mice with a reduction of alpha(5)GABA(A) receptors in the hippocampus or a selective deletion of glycine transporter 1 (GlyT1) in the forebrain. Both genetic manipulations altered the formation or persistence of associative links leading to distinct phenotypes on trace conditioning, extinction learning, latent inhibition, working memory, and object recognition. Behavioural assays of latent inhibition, prepulse inhibition, working memory, and sensitivity to psychostimulants in particular suggest that alpha(3) and alpha(5) subunit-containing GABA(A) receptors as well as GlyT1 are potential sites for ameliorating psychotic-like behaviour. Taken together, these results qualify distinct GABA-A receptor subtypes and GlyT1 as molecular targets for the development of a new pharmacology in the treatment of cognitive decline and psychotic symptoms.

  10. Hippocampal GABA transporter distribution in patients with temporal lobe epilepsy and hippocampal sclerosis

    NARCIS (Netherlands)

    Schijns, O.; Karaca, U.; Andrade, P.; Nijs, L. de; Kusters, B.; Peeters, A.; Dings, J.; Pannek, H.; Ebner, A.; Rijkers, K.; Hoogland, G.


    PURPOSE: To determine hippocampal expression of neuronal GABA-transporter (GAT-1) and glial GABA-transporter (GAT-3) in patients with temporal lobe epilepsy (TLE) and hippocampal sclerosis (HS). METHODS: Hippocampal sections were immunohistochemically stained for GABA-transporter 1 and GABA-transpor

  11. An Electrostatic Funnel in the GABA-Binding Pathway.

    Directory of Open Access Journals (Sweden)

    Timothy S Carpenter


    Full Text Available The γ-aminobutyric acid type A receptor (GABAA-R is a major inhibitory neuroreceptor that is activated by the binding of GABA. The structure of the GABAA-R is well characterized, and many of the binding site residues have been identified. However, most of these residues are obscured behind the C-loop that acts as a cover to the binding site. Thus, the mechanism by which the GABA molecule recognizes the binding site, and the pathway it takes to enter the binding site are both unclear. Through the completion and detailed analysis of 100 short, unbiased, independent molecular dynamics simulations, we have investigated this phenomenon of GABA entering the binding site. In each system, GABA was placed quasi-randomly near the binding site of a GABAA-R homology model, and atomistic simulations were carried out to observe the behavior of the GABA molecules. GABA fully entered the binding site in 19 of the 100 simulations. The pathway taken by these molecules was consistent and non-random; the GABA molecules approach the binding site from below, before passing up behind the C-loop and into the binding site. This binding pathway is driven by long-range electrostatic interactions, whereby the electrostatic field acts as a 'funnel' that sweeps the GABA molecules towards the binding site, at which point more specific atomic interactions take over. These findings define a nuanced mechanism whereby the GABAA-R uses the general zwitterionic features of the GABA molecule to identify a potential ligand some 2 nm away from the binding site.

  12. Adrenergic drugs modify the level of noradrenaline in the insular cortex and alter extinction of conditioned taste aversion in rats. (United States)

    Fresquet, Nadine; Angst, Marie-Josée; Schleef, Carmen; Gobaille, Serge; Sandner, Guy


    We compared the effect of conditioned taste aversion in rats by measuring the amount of sucrose that they drunk after conditioning, which differed according to whether rats had drunk the sucrose freely (SD: self drinking) during the conditioning session, or had been forced to drink it (IO: intra-oral administration through a chronically implanted cannula). The SD procedure delayed the extinction of conditioned taste aversion. Enhanced arousal, alertness, awareness or attention in the SD condition may have strengthened the memory of the taste. Brain noradrenergic networks are involved in such processes. We administered two noradrenergic drugs that produce opposite effects on noradrenaline release in the brain, methoxy-idazoxan, RX821002 (1mg/kg, i.p.), and guanfacine (0.12mg/kg, i.p.). We evaluated their effect (i) on the level of noradrenaline in the gustatory cortex using microdialysis, (ii) on glycaemia that is an essential factor of taste learning and (iii) on the comparative SD versus IO conditioned taste aversion protocol mentioned above. Injecting RX821001 increased the level of noradrenaline in the gustatory cortex up to two-fold of the baseline. This effect lasted 1h. The same dose of RX821002 did not elicit any alteration of glycaemia. It enhanced extinction of conditioned taste aversion in the SD group of rats. Injecting 0.12mg/kg of guanfacine produced the opposite effect. The noradrenaline level of the gustatory cortex decreased, but only down to 20% of the baseline. This decrease lasted 2h. Guanfacine increased glycaemia. Extinction of conditioned taste aversion was only marginally decreased by guanfacine in the SD group of rats. These results fit with Aston-Jones' point of view that the role of the noradrenergic coeruleo-cortical system may be to enhance arousal, alertness, awareness or attention to an event by a transient increase of cortical noradrenaline.

  13. Neonatal pain-related stress and NFKBIA genotype are associated with altered cortisol levels in preterm boys at school age. (United States)

    Grunau, Ruth E; Cepeda, Ivan L; Chau, Cecil M Y; Brummelte, Susanne; Weinberg, Joanne; Lavoie, Pascal M; Ladd, Mihoko; Hirschfeld, Aaron F; Russell, Evan; Koren, Gideon; Van Uum, Stan; Brant, Rollin; Turvey, Stuart E


    Neonatal pain-related stress is associated with elevated salivary cortisol levels to age 18 months in children born very preterm, compared to full-term, suggesting early programming effects. Importantly, interactions between immune/inflammatory and neuroendocrine systems may underlie programming effects. We examined whether cortisol changes persist to school age, and if common genetic variants in the promoter region of the NFKBIA gene involved in regulation of immune and inflammatory responses, modify the association between early experience and later life stress as indexed by hair cortisol levels, which provide an integrated index of endogenous HPA axis activity. Cortisol was assayed in hair samples from 128 children (83 born preterm ≤ 32 weeks gestation and 45 born full-term) without major sensory, motor or cognitive impairments at age 7 years. We found that hair cortisol levels were lower in preterm compared to term-born children. Downregulation of the HPA axis in preterm children without major impairment, seen years after neonatal stress terminated, suggests persistent alteration of stress system programming. Importantly, the etiology was gender-specific such that in preterm boys but not girls, specifically those with the minor allele for NFKBIA rs2233409, lower hair cortisol was associated with greater neonatal pain (number of skin-breaking procedures from birth to term), independent of medical confounders. Moreover, the minor allele (CT or TT) of NFKBIA rs2233409 was associated with higher secretion of inflammatory cytokines, supporting the hypothesis that neonatal pain-related stress may act as a proinflammatory stimulus that induces long-term immune cell activation. These findings are the first evidence that a long-term association between early pain-related stress and cortisol may be mediated by a genetic variants that regulate the activity of NF-κB, suggesting possible involvement of stress/inflammatory mechanisms in HPA programming in boys born very

  14. Rice Stripe Virus Infection Alters mRNA Levels of Sphingolipid-Metabolizing Enzymes and Sphingolipids Content in Laodelphax striatellus (United States)

    Li, Fei-Qiang; Bai, Yue-Liang; Shi, Xiao-Xiao; Zhu, Mu-Fei; Zhang, Min-Jing; Mao, Cun-Gui; Zhu, Zeng-Rong


    Sphingolipids and their metabolites have been implicated in viral infection and replication in mammal cells but how their metabolizing enzymes in the host are regulated by viruses remains largely unknown. Here we report the identification of 12 sphingolipid genes and their regulation by Rice stripe virus in the small brown planthopper (Laodelphax striatellus Fallén), a serious pest of rice throughout eastern Asia. According to protein sequence similarity, we identified 12 sphingolipid enzyme genes in L. striatellus. By comparing their mRNA levels in viruliferous versus nonviruliferous L. striatellus at different life stages by qPCR, we found that RSV infection upregulated six genes (LsCGT1, LsNAGA1, LsSGPP, LsSMPD4, LsSMS, and LsSPT) in most stages of L. striatellus. Especially, four genes (LsCGT1, LsSMPD2, LsNAGA1, and LsSMS) and another three genes (LsNAGA1, LsSGPP, and LsSMS) were significantly upregulated in viruliferous third-instar and fourth-instar nymphs, respectively. HPLC-MS/MS results showed that RSV infection increased the levels of various ceramides, such as Cer18:0, Cer20:0, and Cer22:0 species, in third and fourth instar L. striatellus nymphs. Together, these results demonstrate that RSV infection alters the transcript levels of various sphingolipid enzymes and the contents of sphingolipids in L. striatellus, indicating that sphingolipids may be important for RSV infection or replication in L. striatellus. PMID:28130458

  15. Cloning and sequencing of mouse GABA transporter complementary DNA

    Institute of Scientific and Technical Information of China (English)



    A cDNA encoding the mouse GABA transporter has been isolated and sequenced.The results show that the mouse GABA transporter cDNA differs from that of the rat by 60 base pairs at the open reading frame region but the deduced amino acid sequences of the two cDNAs are identical and both composed of 599 amino acids.However,the amino acid sequence is different from the sequence deduced from a recently published mouse GABA transporter cDNA.

  16. Reduced parahippocampal and lateral temporal GABA{sub A}-[{sup 11}C]flumazenil binding in major depression: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Klumpers, Ursula M.H. [VU University Medical Center, Department of Psychiatry, Amsterdam (Netherlands); GGZ inGeest, partner of VUmc, Department of Psychiatry, Amsterdam (Netherlands); VU University Medical Center, Neuroscience Campus Amsterdam, Amsterdam (Netherlands); Veltman, Dick J. [VU University Medical Center, Department of Psychiatry, Amsterdam (Netherlands); VU University Medical Center, Neuroscience Campus Amsterdam, Amsterdam (Netherlands); Drent, Madeleine L. [VU University Medical Center, Department of Endocrinology, Amsterdam (Netherlands); Boellaard, Ronald; Lammertsma, Adriaan A. [VU University Medical Center, Department of Nuclear Medicine and PET Research, Amsterdam (Netherlands); VU University Medical Center, Neuroscience Campus Amsterdam, Amsterdam (Netherlands); Comans, Emile F.I. [VU University Medical Center, Department of Nuclear Medicine and PET Research, Amsterdam (Netherlands); Meynen, Gerben [VU University Medical Center, Department of Psychiatry, Amsterdam (Netherlands); Hoogendijk, Witte J.G. [VU University Medical Center, Department of Psychiatry, Amsterdam (Netherlands); VU University Medical Center, Center for Neurogenomics and Cognitive Research, Amsterdam (Netherlands); VU University Medical Center, Neuroscience Campus Amsterdam, Amsterdam (Netherlands)


    Major depressive disorder (MDD) has been related to both a dysfunctional {gamma}-amino butyric acid (GABA) system and to hyperactivity of the hypothalamic-pituitary-adrenal axis (HPA). Although GABA has been suggested to inhibit HPA axis activity, their relationship has never been studied at the level of the central GABA{sub A}-benzodiazepine receptor in depressed patients or in relation to antidepressant treatment. Eleven depressed outpatients were compared, before and after treatment with citalopram, with nine age-matched healthy controls. The subjects were scanned using the positron emission tomography (PET) tracer [{sup 11}C]flumazenil ([{sup 11}C]FMZ). Parametric voxel-by-voxel Logan plots were compared with methods based on regions of interest (ROI), to provide volume of distribution (V{sub T}) and binding potential (BP{sub ND}) values. Plasma GABA levels were determined and a dexamethasone-corticotropin releasing hormone (DEX-CRH) test was performed. In MDD, parametric voxel-by-voxel Logan plots showed bilateral reduced [{sup 11}C]FMZ binding in the parahippocampal gyrus and right lateral superior temporal gyrus (p uncorrected {<=}0.001). In the temporal area, [{sup 11}C]FMZ binding showed a strong inverse correlation with HPA axis activity. Plasma GABA did not discriminate MDD from controls, but correlated inversely with [{sup 11}C]FMZ binding in the right insula. Following treatment with citalopram, voxel-based analysis revealed reduced binding in the right lateral temporal gyrus and dorsolateral prefrontal cortex. The bilateral reduction in limbic parahippocampal and right temporal [{sup 11}C]FMZ binding found in MDD indicates decreased GABA{sub A}-benzodiazepine receptor complex affinity and/or number. The inverse relationship between GABA{sub A} binding in the temporal lobe and HPA axis activity, suggests that HPA axis hyperactivity is partly due to reduced GABA-ergic inhibition. (orig.)

  17. Low nanomolar GABA effects at extrasynaptic a4ß1/ß3delta GABAA receptor subtypes indicate a different binding mode for GABA at these receptors

    DEFF Research Database (Denmark)

    Karim, Nasiara; Wellendorph, Petrine; Absalom, Nathan;


    Ionotropic GABA(A) receptors are a highly heterogenous population of receptors assembled from a combination of multiple subunits. The aims of this study were to characterize the potency of GABA at human recombinant d-containing extrasynaptic GABA(A) receptors expressed in Xenopus oocytes using th...

  18. Chemical integrity of ( sup 3 H)GABA used in binding studies

    Energy Technology Data Exchange (ETDEWEB)

    Balcar, V.J. (Univ. of Sydney, N.S.W. (Australia))


    A method which is claimed to be able to determine the proportion of true GABA within radiolabeled GABA used in binding studies was tested using (3H)GABA. The method was found to be unsuitable for {sup 3}H-labeled GABA and, furthermore, both theoretical considerations and the present experimental data indicated that it could also produce misleading results with ({sup 14}C)GABA.

  19. Oxytocin-mediated GABA inhibition during delivery attenuates autism pathogenesis in rodent offspring. (United States)

    Tyzio, Roman; Nardou, Romain; Ferrari, Diana C; Tsintsadze, Timur; Shahrokhi, Amene; Eftekhari, Sanaz; Khalilov, Ilgam; Tsintsadze, Vera; Brouchoud, Corinne; Chazal, Genevieve; Lemonnier, Eric; Lozovaya, Natalia; Burnashev, Nail; Ben-Ari, Yehezkel


    We report that the oxytocin-mediated neuroprotective γ-aminobutyric acid (GABA) excitatory-inhibitory shift during delivery is abolished in the valproate and fragile X rodent models of autism. During delivery and subsequently, hippocampal neurons in these models have elevated intracellular chloride levels, increased excitatory GABA, enhanced glutamatergic activity, and elevated gamma oscillations. Maternal pretreatment with bumetanide restored in offspring control electrophysiological and behavioral phenotypes. Conversely, blocking oxytocin signaling in naïve mothers produced offspring having electrophysiological and behavioral autistic-like features. Our results suggest a chronic deficient chloride regulation in these rodent models of autism and stress the importance of oxytocin-mediated GABAergic inhibition during the delivery process. Our data validate the amelioration observed with bumetanide and oxytocin and point to common pathways in a drug-induced and a genetic rodent model of autism.

  20. Omega-3 Fatty Acid Enriched Chevon (Goat Meat Lowers Plasma Cholesterol Levels and Alters Gene Expressions in Rats

    Directory of Open Access Journals (Sweden)

    Mahdi Ebrahimi


    Full Text Available In this study, control chevon (goat meat and omega-3 fatty acid enriched chevon were obtained from goats fed a 50% oil palm frond diet and commercial goat concentrate for 100 days, respectively. Goats fed the 50% oil palm frond diet contained high amounts of α-linolenic acid (ALA in their meat compared to goats fed the control diet. The chevon was then used to prepare two types of pellets (control or enriched chevon that were then fed to twenty-male-four-month-old Sprague-Dawley rats (n=10 in each group for 12 weeks to evaluate their effects on plasma cholesterol levels, tissue fatty acids, and gene expression. There was a significant increase in ALA and docosahexaenoic acid (DHA in the muscle tissues and liver of the rats fed the enriched chevon compared with the control group. Plasma cholesterol also decreased (P<0.05 in rats fed the enriched chevon compared to the control group. The rat pellets containing enriched chevon significantly upregulated the key transcription factor PPAR-γ and downregulated SREBP-1c expression relative to the control group. The results showed that the omega-3 fatty acid enriched chevon increased the omega-3 fatty acids in the rat tissues and altered PPAR-γ and SREBP-1c genes expression.

  1. Sleep-deprivation induces changes in GABA(B and mGlu receptor expression and has consequences for synaptic long-term depression.

    Directory of Open Access Journals (Sweden)

    Ramakrishna Tadavarty

    Full Text Available Long term depression (LTD in the CA1 region of the hippocampus, induced with a 20-Hz, 30 s tetanus to Schaffer collaterals, is enhanced in sleep-deprived (SD rats. In the present study, we investigated the role of metabotropic glutamate receptors (mGluRs, γ-aminobutyric acid (GABA B receptors (GABA(B-Rs and N-methyl-D-aspartic acid receptors (NMDARs in the LTD of the population excitatory postsynaptic potential (pEPSP. The requirement of Ca(2+ from L- and T-type voltage-gated calcium channels (VGCCs and intracellular stores was also studied. Results indicate that mGluRs, a release of Ca(2+ from intracellular stores and GABA(B-Rs are required for LTD. Interestingly, while mGlu1Rs seem to be involved in both short-term depression and LTD, mGlu5Rs appear to participate mostly in LTD. CGP 55845, a GABA(B-R antagonist, partially suppressed LTD in normally sleeping (NS rats, while completely blocking LTD in SD rats. Moreover, GS-39783, a positive allosteric modulator for GABA(B-R, suppressed the pEPSP in SD, but not NS rats. Since both mGluRs and GABA(B-Rs seem to be involved in the LTD, especially in SD rats, we examined if the receptor expression pattern and/or dimerization changed, using immunohistochemical, co-localization and co-immunoprecipitation techniques. Sleep-deprivation induced an increase in the expression of GABA(B-R1 and mGlu1αR in the CA1 region of the hippocampus. In addition, co-localization and heterodimerization between mGlu1αR/GABA(B-R1 and mGlu1αR/GABA(B-R2 is enhanced in SD rats. Taken together, our findings present a novel form of LTD sensitive to the activation of mGluRs and GABA(B-Rs, and reveal, for the first time, that sleep-deprivation induces alterations in the expression and dimerization of these receptors.

  2. Altered blood oxygen level-dependent signal variability in chronic post-traumatic stress disorder during symptom provocation

    Directory of Open Access Journals (Sweden)

    Ke J


    Full Text Available Jun Ke,1,* Li Zhang,2,* Rongfeng Qi,1,* Qiang Xu,1 Weihui Li,2 Cailan Hou,3 Yuan Zhong,1 Zhiqiang Zhang,1 Zhong He,4 Lingjiang Li,2,5 Guangming Lu11Department of Medical Imaging, Jinling Hospital, Medical School of Nanjing University, Nanjing, 2Mental Health Institute, the Second Xiangya Hospital, National Technology Institute of Psychiatry, Key Laboratory of Psychiatry and Mental Health of Hunan Province, Central South University, Changsha, 3Guangdong Academy of Medical Science, Guangdong General Hospital, Guangdong Mental Health Center, Guangzhou, 4Department of Radiology of the Second Xiangya Hospital, Central South University, Changsha, 5Shenzhen Kangning Hospital of Guangdong Province, Shenzhen, People’s Republic of China*These authors contributed equally to this workBackground: Recent research suggests that variability in brain signal provides important information about brain function in health and disease. However, it is unknown whether blood oxygen level-dependent (BOLD signal variability is altered in post-traumatic stress disorder (PTSD. We aimed to identify the BOLD signal variability changes of PTSD patients during symptom provocation and compare the brain patterns of BOLD signal variability with those of brain activation.Methods: Twelve PTSD patients and 14 age-matched controls, who all experienced a mining accident, underwent clinical assessment as well as fMRI scanning while viewing trauma-related and neutral pictures. BOLD signal variability and brain activation were respectively examined with standard deviation (SD and general linear model analysis, and compared between the PTSD and control groups. Multiple regression analyses were conducted to explore the association between PTSD symptom severity and these two brain measures across all subjects as well as in the PTSD group.Results: PTSD patients showed increased activation in the middle occipital gyrus compared with controls, and an inverse correlation was found between PTSD

  3. Energy substrate availability as a determinant of neuronal resting potential, GABA signaling and spontaneous network activity in the neonatal cortex in vitro. (United States)

    Holmgren, Carl D; Mukhtarov, Marat; Malkov, Anton E; Popova, Irina Y; Bregestovski, Piotr; Zilberter, Yuri


    While the ultimate dependence of brain function on its energy supply is evident, how basic neuronal parameters and network activity respond to energy metabolism deviations is unresolved. The resting membrane potential (E(m)) and reversal potential of GABA-induced anionic currents (E(GABA)) are among the most fundamental parameters controlling neuronal excitability. However, alterations of E(m) and E(GABA) under conditions of metabolic stress are not sufficiently documented, although it is well known that metabolic crisis may lead to neuronal hyper-excitability and aberrant neuronal network activities. In this work, we show that in slices, availability of energy substrates determines whether GABA signaling displays an inhibitory or excitatory mode, both in neonatal neocortex and hippocampus. We demonstrate that in the neonatal brain, E(m) and E(GABA) strongly depend on composition of the energy substrate pool. Complementing glucose with ketone bodies, pyruvate or lactate resulted in a significant hyperpolarization of both E(m) and E(GABA), and induced a radical shift in the mode of GABAergic synaptic transmission towards network inhibition. Generation of giant depolarizing potentials, currently regarded as the hallmark of spontaneous neonatal network activity in vitro, was strongly inhibited both in neocortex and hippocampus in the energy substrate enriched solution. Based on these results we suggest the composition of the artificial cerebrospinal fluid, which bears a closer resemblance to the in vivo energy substrate pool. Our results suggest that energy deficits induce unfavorable changes in E(m) and E(GABA), leading to neuronal hyperactivity that may initiate a cascade of pathological events.

  4. Acupuncture reduces relapse to cocaine-seeking behavior via activation of GABA neurons in the ventral tegmental area. (United States)

    Jin, Wyju; Kim, Min Sun; Jang, Eun Young; Lee, Jun Yeon; Lee, Jin Gyeom; Kim, Hong Yu; Yoon, Seong Shoon; Lee, Bong Hyo; Chang, Suchan; Kim, Jae Hyo; Choi, Kwang H; Koo, Ho; Gwak, Young Seob; Steffensen, Scott C; Ryu, Yeon-Hee; Kim, Hee Young; Yang, Chae Ha


    There is growing public interest in alternative approaches to addiction treatment and scientific interest in elucidating the neurobiological underpinnings of acupuncture. Our previous studies showed that acupuncture at a specific Shenmen (HT7) points reduced dopamine (DA) release in the nucleus accumbens (NAc) induced by drugs of abuse. The present study was carried out to evaluate the effects of HT7 acupuncture on γ-aminobutyric acid (GABA) neuronal activity in the ventral tegmental area (VTA) and the reinstatement of cocaine-seeking behavior. Using microdialysis and in vivo single-unit electrophysiology, we evaluated the effects of HT7 acupuncture on VTA GABA and NAc DA release and VTA GABA neuronal activity in rats. Using a within-session reinstatement paradigm in rats self-administering cocaine, we evaluated the effects of HT7 stimulation on cocaine-primed reinstatement. Acupuncture at HT7 significantly reduced cocaine suppression of GABA release and GABA neuron firing rates in the VTA. HT7 acupuncture attenuated cocaine-primed reinstatement, which was blocked by VTA infusions of the selective GABAB receptor antagonist 2-hydroxysaclofen. HT7 stimulation significantly decreased acute cocaine-induced DA release in the NAc, which was also blocked by 2-hydroxysaclofen. HT7 acupuncture also attenuated cocaine-induced sensitization of extracellular DA levels in the NAc. Moreover, HT7 acupuncture reduced both locomotor activity and neuronal activation in the NAc induced by acute cocaine in a needle-penetration depth-dependent fashion. These results suggest that acupuncture may suppress cocaine-induced DA release in the NAc and cocaine-seeking behavior through activation of VTA GABA neurons. Acupuncture may be an effective therapy to reduce cocaine relapse by enhancing GABAergic inhibition in the VTA.

  5. Dual role of GABA in the neonatal rat hippocampus. (United States)

    Khalilov, I; Dzhala, V; Ben-Ari, Y; Khazipov, R


    The effects of modulators of GABA-A receptors on neuronal network activity were studied in the neonatal (postnatal days 0-5) rat hippocampus in vitro. Under control conditions, the physiological pattern of activity of the neonatal hippocampal network was characterized by spontaneous network-driven giant depolarizing potentials (GDPs). The GABA-A receptor agonist isoguvacine (1-2 microM) and the allosteric modulator diazepam (2 microM) induced biphasic responses: initially the frequency of GDPs increased 3 to 4 fold followed by blockade of GDPs and desynchronization of the network activity. The GABA-A receptor antagonists bicuculline (10 microM) and picrotoxin (100 microM) blocked GDPs and induced glutamate (AMPA and NMDA)-receptor-mediated interictal- and ictal-like activities in the hippocampal slices and the intact hippocampus. These data suggest that at early postnatal ages GABA can exert a dual - both excitatory and inhibitory - action on the network activity.

  6. [GABA-Receptors in Modulation of Fear Memory Extinction]. (United States)

    Dubrovina, N I


    GABA is the major inhibitory neurotransmitter in the central nervous system determining the efficacy of neuronal interaction. GABA-receptors play a key role in different aspects of fear memory--acquisition and consolidation, retention, reconsolidation and extinction. Extinction is an important behavioural phenomenon which allows organism to adapt its behavior to a changing environment. Extinction of fear memory is a form of new inhibitory learning which interferes with expression of the initial acquired fear conditioning. Resistance to extinction is symptom of depression and posttraumatic stress disorder. The aim of the present review was to summarize own and literary data about GABAergic modulation of fear extinction and pharmacological correction of extinction impairment at influences on GABA(A)- and GABA(B)- receptors.

  7. 大鼠生后MGBv神经元主动膜特性的变化及GABA受体激动剂的影响%Alteration of membrane properties of MGBv neurons and the effect of GABA receptor agonist on them during postnatal development in rats

    Institute of Scientific and Technical Information of China (English)

    姚小红; 万子兵; 熊鹰


    Objective To observe membrane properties of ventral partition of the medial geniculate body (MGBv) in Wistar rat and the effect of GABA receptor agonist on them during postnatal development. Methods Whole-cell patch clamp recording was used to record waveform of action potential (AP) and the effect of GABA receptor agonist on them from neurons in the MGBv of rats ( postnatal days 3-30). Results There was a difference in AP firing pattern in rat MGBv neurons of different postnatal day. We only recorded low threshold Ca2+ spikes (LTS) in P3 MGBv neurons, but recorded AP in P6-30 MGBv neurons after depolarizing currents application; AP was recorded at the start phase of pulse and with a long-last after hyperpolarization potential (AHP) in P8, in P20 AP was recorded after a delay and it appeared on depolarizing ramp with a shorter-last AHP compared with P8. The GABAA receptor agonist, muscimol, and the GABAB receptor agonist, baclofen, had effects on responses evoked by depolarizing current in the MGBv neurons in P6 and P15 rats. Muscimol and baclofen reduced AP firing rather than AP amplitude in P6 MGBv neurons, however, in P15 MGBv neurons baclofen had little effect on AP firing while muscimol greatly reduced the size of voltage shift produced by positive or negative current injection. Conclusion The AP waveform of MGBv neurons matures rapidly during first two postnatal weeks. A similar rapid maturation also has been observed in rat neocortical and hippocampal pyramidal neurons as well as in ferret dorsal lateral geniculate nucleus (LGNd) neurons. These results suggest that in the central nervous system of small mammals, AP waveforms mature rapidly in many types of neurons, thus, coordinated activities in neuronal circuits may occur. In early postnatal development, GABA receptor mainly mediates an excitation effect, depolarizes P6 MGBv neurons and dramatically increases the frequency of AP firing. Inhibition of GABA receptor matures slowly along with increment of

  8. GABA A receptor abnormalities in Prader-Willi syndrome assessed with positron emission tomography and [11C]flumazenil. (United States)

    Lucignani, Giovanni; Panzacchi, Andrea; Bosio, Laura; Moresco, Rosa Maria; Ravasi, Laura; Coppa, Isabella; Chiumello, Giuseppe; Frey, Kirk; Koeppe, Robert; Fazio, Ferruccio


    Prader-Willi syndrome (PWS) is a multi-system disorder characterized clinically by abnormal mental and physical development. PWS patients have a deletion in an imprinted region on paternal chromosome 15 (15q11-13), maternal disomy for this segment, or rarely, a chromosomal imprinting center deletion that gives rise to suppression of the equivalent paternal genes. Within the affected segment of chromosome 15 are genes encoding the alpha(5), beta(3) and gamma(3) subunits of the gamma-aminobutyric acid type-A (GABA(A)) receptor. Therefore, altered neurobehavioral function could arise in PWS due directly to altered GABA(A) receptor composition and expression, or alternatively, from brain developmental and maturational effects of these or other genes in the imprinted region. The aim of the present study was to assess cerebral GABA(A) receptors in PWS with the use of positron emission tomography of the benzodiazepine binding site employing [11C]flumazenil ([11C]FMZ). A reduction in [11C]FMZ binding was found predominantly in the cingulate, frontal and temporal neocortices and insula in six adult PWS patients compared to nine normal subjects. A possible role for the deleted beta(3) subunit gene in PWS is supported in part by the wide cortical distribution of its mRNA expression and the effects of experimental knockouts on benzodiazepine binding described in prior studies. Altered GABA(A) receptor composition or number in these cortical regions may account for neurobehavioral abnormalities in PWS including mild mental retardation, poor impulse control, and impaired responses to somatic pain.

  9. Benzodiazepines do not potentiate GABA responses in neonatal hippocampal neurons. (United States)

    Rovira, C; Ben-Ari, Y


    Benzodiazepines (midazolam; flunitrazepam) and pentobarbital increase the response to exogenous gamma-aminobutyric acid (GABA) in adult hippocampal cells. We report in this paper that in contrast pentobarbital but not benzodiazepine potentiate the effects of exogenous (GABA) in neurons recorded from slices of less than two weeks old. This finding suggests that the functional association of benzodiazepine and GABAA receptors is changed during early postnatal life.

  10. The glutamate-glutamine(GABA cycle: importance of late postnatal development and potential reciprocal interactions between biosynthesis and degradation

    Directory of Open Access Journals (Sweden)

    Leif eHertz


    Full Text Available The gold standard for studies of glutamate-glutamine(GABA cycling and its connections to brain biosynthesis from glucose of glutamate and GABA and their subsequent metabolism are the elegant in vivo studies by 13C magnetic resonance spectroscopy (NMR, showing the large fluxes in the cycle. However, simpler experiments in intact brain tissue (e.g. immunohistochemistry, brain slices, cultured brain cells and mitochondria have also made important contributions to the understanding of details, mechanisms and functional consequences of glutamate/GABA biosynthesis and degradation. The purpose of this review is to attempt to integrate evidence from different sources regarding i the enzyme(s responsible for the initial conversion of -ketoglutarate to glutamate; ii the possibility that especially glutamate oxidation is essentially confined to astrocytes; and iii the ontogenetically very late onset and maturation of glutamine-glutamate(GABA cycle function. Pathway models based on the functional importance of aspartate for glutamate synthesis suggest the possibility of interacting pathways for biosynthesis and degradation of glutamate and GABA and the use of transamination as the default mechanism for initiation of glutamate oxidation. The late development and maturation are related to the late cortical gliogenesis and convert brain cortical function from being purely neuronal to becoming neuronal-astrocytic. This conversion is associated with huge increases in energy demand and production, and the character of potentially incurred gains of function are discussed. These may include alterations in learning mechanisms, in mice indicated by lack of pairing of odor learning with aversive stimuli in newborn animals but the development of such an association 10-12 days later. The possibility is suggested that analogous maturational changes may contribute to differences in the way learning is accomplished in the newborn human brain and during later development.

  11. Accuracy and stability of measuring GABA, glutamate, and glutamine by proton magnetic resonance spectroscopy: A phantom study at 4 Tesla (United States)

    Henry, Michael E.; Lauriat, Tara L.; Shanahan, Meghan; Renshaw, Perry F.; Jensen, J. Eric


    Proton magnetic resonance spectroscopy has the potential to provide valuable information about alterations in gamma-aminobutyric acid (GABA), glutamate (Glu), and glutamine (Gln) in psychiatric and neurological disorders. In order to use this technique effectively, it is important to establish the accuracy and reproducibility of the methodology. In this study, phantoms with known metabolite concentrations were used to compare the accuracy of 2D J-resolved MRS, single-echo 30 ms PRESS, and GABA-edited MEGA-PRESS for measuring all three aforementioned neurochemicals simultaneously. The phantoms included metabolite concentrations above and below the physiological range and scans were performed at baseline, 1 week, and 1 month time-points. For GABA measurement, MEGA-PRESS proved optimal with a measured-to-target correlation of R2 = 0.999, with J-resolved providing R2 = 0.973 for GABA. All three methods proved effective in measuring Glu with R2 = 0.987 (30 ms PRESS), R2 = 0.996 (J-resolved) and R2 = 0.910 (MEGA-PRESS). J-resolved and MEGA-PRESS yielded good results for Gln measures with respective R2 = 0.855 (J-resolved) and R2 = 0.815 (MEGA-PRESS). The 30 ms PRESS method proved ineffective in measuring GABA and Gln. When measurement stability at in vivo concentration was assessed as a function of varying spectral quality, J-resolved proved the most stable and immune to signal-to-noise and linewidth fluctuation compared to MEGA-PRESS and 30 ms PRESS.

  12. Control of cortical neuronal migration by glutamate and GABA

    Directory of Open Access Journals (Sweden)

    Heiko J Luhmann


    Full Text Available Neuronal migration in the cortex is controlled by the paracrine action of the classical neurotransmitters glutamate and GABA. Glutamate controls radial migration of pyramidal neurons by acting primarily on NMDA receptors and regulates tangential migration of inhibitory interneurons by activating non-NMDA and NMDA receptors. GABA, acting on ionotropic GABAA-rho and GABAA receptors, has a dichotomic action on radially migrating neurons by acting as a GO signal in lower layers and as a STOP signal in upper cortical plate (CP, respectively. Metabotropic GABAB receptors promote radial migration into the CP and tangential migration of interneurons. Besides GABA, the endogenous GABAergic agonist taurine is a relevant agonist controlling radial migration. To a smaller extent glycine receptor activation can also influence radial and tangential migration. Activation of glutamate and GABA receptors causes increases in intracellular Ca2+ transients, which promote neuronal migration by acting on the cytoskeleton. Pharmacological or genetic manipulation of glutamate or GABA receptors during early corticogenesis induce heterotopic cell clusters in upper layers and loss of cortical lamination, i.e. neuronal migration disorders which can be associated with neurological or neuropsychiatric diseases. The pivotal role of NMDA and ionotropic GABA receptors in cortical neuronal migration is of major clinical relevance, since a number of drugs acting on these receptors (e.g. anti-epileptics, anesthetics, alcohol may disturb the normal migration pattern when present during early corticogenesis.

  13. The language of GABA in pollen tube growth and guidance

    Institute of Scientific and Technical Information of China (English)

    Guanghui YU; Yan CHEN


    The achievement of double fertilization in higher plants requires the successful transport of sperm cells to the female gametes, the ovules. Pollen tubes, the tubular structure protruding from pollens, carrying the sperms play an important role in this process. How a pollen tube precisely guides its direction to gain its goal is of mystery. Previous investigation indicated that mul-tiple signal clues from the pistils function as the route signs to regulate the pathway of pollen tube growth. Among the signal clues, γ-aminobutyric acid (GABA) seems to be universal. Its gradient concentration has been found both in tobacco and Arabidopsis pollen tube guid-ance. In the communication of pollens and pistils, what on earth GABA tells pollen tubes is of great interest. The GABA receptors on the pollen membrane are thought to be the hinge in the language conversation. In this review, the mechanism of GABA gradient formation is investigated. The possible GABA receptor on the pollen membrane is examined and its function is discussed. To decipher the possible language of GABA in pollen tube growth and guidance, multiple methods are needed. The combination of transcriptome and proteomics assay is expected to unveil the secret.

  14. The GABA excitatory/inhibitory developmental sequence: a personal journey. (United States)

    Ben-Ari, Y


    The developing brain is talkative but its language is not that of the adult. Most if not all voltage and transmitter-gated ionic currents follow a developmental sequence and network-driven patterns differ in immature and adult brains. This is best illustrated in studies engaged almost three decades ago in which we observed elevated intracellular chloride (Cl(-))i levels and excitatory GABA early during development and a perinatal excitatory/inhibitory shift. This sequence is observed in a wide range of brain structures and animal species suggesting that it has been conserved throughout evolution. It is mediated primarily by a developmentally regulated expression of the NKCC1 and KCC2 chloride importer and exporter respectively. The GABAergic depolarization acts in synergy with N-methyl-d-aspartate (NMDA) receptor-mediated and voltage-gated calcium currents to enhance intracellular calcium exerting trophic effects on neuritic growth, migration and synapse formation. These sequences can be deviated in utero by genetic or environmental insults leading to a persistence of immature features in the adult brain. This "neuroarcheology" concept paves the way to novel therapeutic perspectives based on the use of drugs that block immature but not adult currents. This is illustrated notably with the return to immature high levels of chloride and excitatory actions of GABA observed in many pathological conditions. This is due to the fact that in the immature brain a down regulation of KCC2 and an up regulation of NKCC1 are seen. Here, I present a personal history of how an unexpected observation led to novel concepts in developmental neurobiology and putative treatments of autism and other developmental disorders. Being a personal account, this review is neither exhaustive nor provides an update of this topic with all the studies that have contributed to this evolution. We all rely on previous inventors to allow science to advance. Here, I present a personal summary of this

  15. Temporal development of GABA agonist induced alterations in ultrastructure and GABA receptor expression in cultured cerebellar granule cells

    DEFF Research Database (Denmark)

    Hansen, G H; Belhage, B; Schousboe, A


    . It was found that the cytoplasmic density of smooth endoplasmic reticulum was decreased, while the cytoplasmic density of rough endoplasmic reticulum, Golgi apparatus, vesicles and coated vesicles was greatly enhanced after exposure of the cells to THIP (150 microM) for only 1 hr. In cerebellar granule cells...

  16. Pharmacological characterization of homobaclofen on wild type and mutant GABA(B)1b receptors coexpressed with the GABA(B)2 receptor

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Madsen, Bo E.; Krogsgaard-Larsen, P;


    Homobaclofen (5-amino-3-(4-chlorophenyl) pentanoic acid) is a homologue of the classical GABA(B) receptor agonist baclofen. In a recent study, the two enantiomers of this compound were tested in a GABA(B) receptor selective [3H]gamma-aminobutyric acid ([3H]GABA) binding assay using rat brain homo...

  17. Co-Localization of GABA Shunt Enzymes for the Efficient Production of Gamma-Aminobutyric Acid via GABA Shunt Pathway in Escherichia coli. (United States)

    Pham, Van Dung; Somasundaram, Sivachandiran; Park, Si Jae; Lee, Seung Hwan; Hong, Soon Ho


    Gamma-aminobutyric acid (GABA) is a non-protein amino acid, which is an important inhibitor of neurotransmission in the human brain. GABA is also used as the precursor of biopolymer Nylon-4 production. In this study, the carbon flux from the tricarboxylic acid cycle was directed to the GABA shunt pathway for the production of GABA from glucose. The GABA shunt enzymes succinate-semialdehyde dehydrogenase (GabD) and GABA aminotransferase (GabT) were co-localized along with the GABA transporter (GadC) by using a synthetic scaffold complex. The co-localized enzyme scaffold complex produced 0.71 g/l of GABA from 10 g/l of glucose. Inactivation of competing metabolic pathways in mutant E. coli strains XBM1 and XBM6 increased GABA production 13% to reach 0.80 g/l GABA by the enzymes co-localized and expressed in the mutant strains. The recombinant E. coli system developed in this study demonstrated the possibility of the pathway of the GABA shunt as a novel GABA production pathway.

  18. Dysbindin Deficiency Modifies the Expression of GABA Neuron and Ion Permeation Transcripts in the Developing Hippocampus (United States)

    Larimore, Jennifer; Zlatic, Stephanie A.; Arnold, Miranda; Singleton, Kaela S.; Cross, Rebecca; Rudolph, Hannah; Bruegge, Martha V.; Sweetman, Andrea; Garza, Cecilia; Whisnant, Eli; Faundez, Victor


    The neurodevelopmental factor dysbindin is required for synapse function and GABA interneuron development. Dysbindin protein levels are reduced in the hippocampus of schizophrenia patients. Mouse dysbindin genetic defects and other mouse models of neurodevelopmental disorders share defective GABAergic neurotransmission and, in several instances, a loss of parvalbumin-positive interneuron phenotypes. This suggests that mechanisms downstream of dysbindin deficiency, such as those affecting GABA interneurons, could inform pathways contributing to or ameliorating diverse neurodevelopmental disorders. Here we define the transcriptome of developing wild type and dysbindin null Bloc1s8sdy/sdy mouse hippocampus in order to identify mechanisms downstream dysbindin defects. The dysbindin mutant transcriptome revealed previously reported GABA parvalbumin interneuron defects. However, the Bloc1s8sdy/sdy transcriptome additionally uncovered changes in the expression of molecules controlling cellular excitability such as the cation-chloride cotransporters NKCC1, KCC2, and NCKX2 as well as the potassium channel subunits Kcne2 and Kcnj13. Our results suggest that dysbindin deficiency phenotypes, such as GABAergic defects, are modulated by the expression of molecules controlling the magnitude and cadence of neuronal excitability.

  19. Long-Lasting Effects of GABA Infusion Into the Cerebral Cortex of the Rat (United States)

    Montiel, Teresa; Almeida, Daniel; Arango, Iván; Calixto, Eduardo; Casasola, César; Brailowsky, Simón


    In electrophysiological terms, experimental models of durable information storage in the brain include long-term potentiation (LTP), long-term depression, and kindling. Protein synthesis correlates with these enduring processes. We propose a fourth example of long-lasting information storage in the brain, which we call the GABA-withdrawal syndrome (GWS). In rats, withdrawal of a chronic intracortical infusion of GABA, a ubiquitous inhibitory neurotransmitter, induced epileptogenesis at the infusion site. This overt GWS lasted for days. Anisomycin, a protein synthesis inhibitor, prevented the appearance of GWS in vivo. Hippocampal and neocortical slices showed a similar post-GABA hyperexcitability in vitro and an enhanced susceptibility to LTP induction. One to four months after the epileptic behavior disappeared, systemic administration of a subconvulsant dose of pentylenetetrazol produced the reappearance of paroxysmal activity. The long-lasting effects of tonic GABAA receptor stimulation may be involved in long-term information storage processes at the cortical level, whereas the cessation of GABAA receptor stimulation may be involved in chronic pathological conditions, such as epilepsy. Furthermore, we propose that GWS may represent a common key factor in the addiction to GABAergic agents (for example, barbiturates, benzodiazepines, and ethanol). GWS represents a novel form of neurono-glial plasticity. The mechanisms of this phenomenon remain to be understood. PMID:10709209

  20. CXCL12 chemokine and GABA neurotransmitter systems crosstalk and their putative roles

    Directory of Open Access Journals (Sweden)

    Guyon eAlice


    Full Text Available Since CXCL12 and its receptors, CXCR4 and CXCR7, have been found in the brain, the role of this chemokine has been expanded from chemoattractant in the immune system to neuromodulatory in the brain. Several pieces of evidence suggest that this chemokine system could crosstalk with the GABAergic system, known to be the main inhibitory neurotransmitter system in the brain. Indeed, GABA and CXCL12 as well as their receptors are colocalized in many cell types including neurons and there are several examples in which these two systems interact. Several mechanisms can be proposed to explain how these systems interact, including receptor-receptor interactions, crosstalk at the level of second messenger cascades, or direct pharmacological interactions, as GABA and GABAB receptor agonists/antagonists have been shown to be allosteric modulators of CXCR4.The interplay between CXCL12/CXCR4-CXCR7 and GABA/GABAA-GABAB receptors systems could have many physiological implications in neurotransmission, cancer and inflammation. In addition, the GABAB agonist baclofen is currently used in medicine to treat spasticity in patients with spinal cord injury, cerebral palsy, traumatic brain injury, multiple sclerosis and other disorders. More recently it has also been used in the treatment of alcohol dependence and withdrawal. The allosteric effects of this agent on CXCR4 could contribute to these beneficial effects or at the opposite, to its side effects.

  1. Antiseizure Activity of Midazolam in Mice Lacking δ-Subunit Extrasynaptic GABA(A) Receptors. (United States)

    Reddy, Sandesh D; Younus, Iyan; Clossen, Bryan L; Reddy, Doodipala Samba


    Midazolam is a benzodiazepine anticonvulsant with rapid onset and short duration of action. Midazolam is the current drug of choice for acute seizures and status epilepticus, including those caused by organophosphate nerve agents. The antiseizure activity of midazolam is thought to result from its allosteric potentiation of synaptic GABA(A) receptors in the brain. However, there are indications that benzodiazepines promote neurosteroid synthesis via the 18-kDa cholesterol transporter protein (TSPO). Therefore, we investigated the role of neurosteroids and their extrasynaptic GABA(A) receptor targets in the antiseizure activity of midazolam. Here, we used δ-subunit knockout (DKO) mice bearing a targeted deletion of the extrasynaptic receptors to investigate the contribution of the extrasynaptic receptors to the antiseizure activity of midazolam using the 6-Hz and hippocampus kindling seizure models. In both models, midazolam produced rapid and dose-dependent protection against seizures (ED50, 0.4 mg/kg). Moreover, the antiseizure potency of midazolam was undiminished in DKO mice compared with control mice. Pretreatment with PK11195 [1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide], a TSPO blocker, or finasteride, a 5α-reductase neurosteroid inhibitor, did not affect the antiseizure effect of midazolam. The antiseizure activity of midazolam was significantly reversed by pretreatment with flumazenil, a benzodiazepine antagonist. Plasma and brain levels of the neurosteroid allopregnanolone were not significantly greater in midazolam-treated animals. These studies therefore provide strong evidence that neurosteroids and extrasynaptic GABA(A) receptors are not involved in the antiseizure activity of midazolam, which mainly occurs through synaptic GABA(A) receptors via direct binding to benzodiazepine sites. This study reaffirms midazolam's use for controlling acute seizures and status epilepticus.

  2. GABA(A) receptor mediated inhibition contributes to corticostriatal frequency filtering. (United States)

    Jelinek, Devin A; Partridge, L Donald


    The striatum plays an important role in the initiation and learning of skilled motor behavior [6] and receives topographic input from most areas of the cortex. Cortical afferents make divergent contact with many striatal medium spiny neurons while individual medium spiny neurons receive tens of thousands of these glutamatergic synapses [13]. Temporal filtering of frequency information within synaptic fields plays an important role in the processing of neuronal signals. We have previously shown differential filtering characteristics within CA1, CA3, and the dentate gyrus of the hippocampus [26] and have now extended these studies to the cortical input to the dorsal striatum in order to address the network filtering characteristics in this important synaptic field. We measured field potentials of striatal medium spiny neurons in response to layer V cortical input over a range of stimulus frequencies from 2Hz to 100Hz. The average population spike amplitude in response to these stimulus trains exhibited a non-linear relationship to frequency, with characteristics of a low pass filter. In order to assess potential modulation of these filter properties, we examined the frequency response in the presence of antagonists to CB1, D2, nACh, and GABA(A) receptors, which are all known to be expressed at these synapses [13]. Of these, only GABA(A) receptor antagonists significantly modulated the frequency filtering characteristics over the examined frequency range. High frequency stimulation induces long term plasticity at corticostriatal synapses [4] and this process is strengthened when GABA(A) receptors are blocked [7,20,29]. Our results suggest a model whereby a temporary decrease in GABA level would modulate the filtering parameters of the corticostriatal circuit, allowing a more robust induction of high frequency-dependent plasticity.

  3. Allodynia and hyperalgesia in diabetic rats are mediated by GABA and depletion of spinal potassium-chloride co-transporters (United States)

    Jolivalt, Corinne G.; Lee, Corinne A.; Ramos, Khara M.; Calcutt, Nigel A.


    Diabetic rats show behavioral indices of painful neuropathy that may model the human condition. Hyperalgesia during the formalin test in diabetic rats is accompanied by the apparently paradoxical decrease in spinal release of excitatory neurotransmitters and increase in the inhibitory neurotransmitter GABA. Decreased expression of the potassium-chloride co-transporter, KCC2, in the spinal cord promotes excitatory properties of GABA. We therefore measured spinal KCC2 expression and explored the role of the GABAA receptor in rats with painful diabetic neuropathy. KCC2 protein levels were significantly reduced in the spinal cord of diabetic rats while levels of NKCC1 and the GABAA receptor were unchanged. Spinal delivery of the GABAA receptor antagonist bicuculline reduced formalin-evoked flinching in diabetic rats and also dose-dependently alleviated tactile allodynia. GABAA receptor-mediated rate-dependent depression of the spinal H reflex was absent in the spinal cord of diabetic rats. Control rats treated with the KCC2 blocker DIOA, mimicked diabetes by showing increased formalin-evoked flinching and diminished rate dependent depression. The ability of bicuculline to alleviate allodynia and formalin-evoked hyperalgesia in diabetic rats is consistent with a reversal of the properties of GABA predicted by reduced spinal KCC2 and suggests that reduced KCC2 expression and increased GABA release contribute to spinally-mediated hyperalgesia in diabetes. PMID:18755547

  4. Mono-hydroxy methoxychlor alters levels of key sex steroids and steroidogenic enzymes in cultured mouse antral follicles. (United States)

    Craig, Zelieann R; Leslie, Traci C; Hatfield, Kimberly P; Gupta, Rupesh K; Flaws, Jodi A


    Methoxychlor (MXC) is an organochlorine pesticide that reduces fertility in female rodents by decreasing antral follicle numbers and increasing follicular death. MXC is metabolized in the body to mono-hydroxy MXC (mono-OH). Little is known about the effects of mono-OH on the ovary. Thus, this work tested the hypothesis that mono-OH exposure decreases production of 17β-estradiol (E₂) by cultured mouse antral follicles. Antral follicles were isolated from CD-1 mice (age 35-39 days) and exposed to dimethylsulfoxide (DMSO), or mono-OH (0.1-10 μg/mL) for 96 h. Media and follicles were collected for analysis of sex steroid levels and mRNA expression, respectively. Mono-OH treatment (10 μg/mL) decreased E(2) (DMSO: 3009.72±744.99 ng/mL; mono-OH 0.1 μg/mL: 1679.66±461.99 ng/mL; 1 μg/mL: 1752.72±532.41 ng/mL; 10 μg/mL: 45.89±33.83 ng/mL), testosterone (DMSO: 15.43±2.86 ng/mL; mono-OH 0.1μg/mL: 17.17±4.71 ng/mL; 1 μg/mL: 13.64±3.53 ng/mL; 10 μg/mL: 1.29±0.23 ng/mL), androstenedione (DMSO: 1.92±0.34 ng/mL; mono-OH 0.1 μg/mL: 1.49±0.43ng/mL; 1 μg/mL: 0.64±0.31 ng/mL; 10 μg/mL: 0.12±0.06 ng/mL) and progesterone (DMSO: 24.11±4.21 ng/mL; mono-OH 0.1μg/mL: 26.77±4.41 ng/mL; 1 μg/mL: 20.90±3.75 ng/mL; 10 μg/mL: 9.44±2.97 ng/mL) levels. Mono-OH did not alter expression of Star, Hsd3b1, Hsd17b1 and Cyp1b1, but it did reduce levels of Cyp11a1, Cyp17a1 and Cyp19a1 mRNA. Collectively, these data suggest that mono-OH significantly decreases levels of key sex steroid hormones and the expression of enzymes required for steroidogenesis.

  5. Palmitate alters the rhythmic expression of molecular clock genes and orexigenic neuropeptide Y mRNA levels within immortalized, hypothalamic neurons. (United States)

    Fick, Laura J; Fick, Gordon H; Belsham, Denise D


    The control of energy homeostasis within the hypothalamus is under the regulated control of homeostatic hormones, nutrients and the expression of neuropeptides that alter feeding behavior. Elevated levels of palmitate, a predominant saturated fatty acid in diet and fatty acid biosynthesis, alter cellular function. For instance, a key mechanism involved in the development of insulin resistance is lipotoxicity, through increased circulating saturated fatty acids. Although many studies have begun to determine the underlying mechanisms of lipotoxicity in peripheral tissues, little is known about the effects of excess lipids in the brain. To determine these mechanisms we used an immortalized, clonal, hypothalamic cell line, mHypoE-44, to demonstrate that palmitate directly alters the expression of molecular clock components, by increasing Bmal1 and Clock, or by decreasing Per2, and Rev-erbα, their mRNA levels and altering their rhythmic period within individual neurons. We found that these neurons endogenously express the orexigenic neuropeptides NPY and AgRP, thus we determined that palmitate administration alters the mRNA expression of these neuropeptides as well. Palmitate treatment causes a significant increase in NPY mRNA levels and significantly alters the phase of rhythmic expression. We explored the link between AMPK and the expression of neuropeptide Y using the AMPK inhibitor compound C and the AMP analog AICAR. AMPK inhibition decreased NPY mRNA. AICAR also elevated basal NPY, but prevented the palmitate-mediated increase in NPY mRNA levels. We postulate that this palmitate-mediated increase in NPY and AgRP synthesis may initiate a detrimental positive feedback loop leading to increased energy consumption.

  6. Higher high density lipoprotein cholesterol associated with moderate alcohol consumption is not related to altered plasma lecithin : cholesterol acyltransferase and lipid transfer protein activity levels

    NARCIS (Netherlands)

    Riemens, SC; vanTol, A; Hoogenberg, K; vanGent, T; Scheek, LM; Sluiter, WJ; Dullaart, RPF


    Lecithin:cholesterol acyltransferase (LCAT), cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP) are important factors involved in HDL metabolism. Altered plasma activity levels of these factors could play a role in the increase in high density lipoprotein (HDL) choles

  7. Seizures beget seizures: the quest for GABA as a key player. (United States)

    Ben-Ari, Yehezkel


    Synapses mediated by gamma-aminobutyric acid (GABA) A receptors are notoriously altered during periods of enhanced activity. Since a loss of inhibitory tone is a basic cause of seizures and epilepsies, it is important to determine the underlying mechanisms and the way this could be alleviated or at least reduced. Alterations of the intracellular content of chloride are thought to be a major player in the sequence of events that follow episodes of hyperactivity. In this review, I discuss these mechanisms both in the adult and developing brain, relying on studies in which chloride and GABAergic currents were measured by electrophysiological and imaging techniques. The main conclusion is that in adult systems, status epilepticus induces a complete re-organization of the networks, with cell death, axonal growth, and glutamatergic neosynapse formation leading to an increased glutamatergic drive. This, in turn, will decrease the threshold of seizure generation and thus contribute to seizure generation. In contrast, GABAergic synapses are not readily "plastic" as the lost interneurones and synapses are not replaced. Somatostatin-positive 0-LM Interneurons that innervate the dendrites of the principal cells in the hippocampus degenerate selectively, leading to a loss of the inhibitory drive in the dendrites, whereas somatic projecting basket cells and somatic inhibitory drives are relatively spared. This imbalance leads to a reduction of the inhibitory strength that is necessary but not sufficient to generate ongoing seizures. An additional important factor is the persistent increase of the intracellular chloride concentration that leads to a long-lasting shift in the depolarizing direction of the actions of GABA that will also contribute to seizure generation. In the developing brain, a major source of seizure generation is the depolarizing and often excitatory actions of GABA due to a higher intracellular chloride concentration ([Cl-]I) in immature neurons, a property

  8. GABA agonist induced changes in ultrastructure and GABA receptor expression in cerebellar granule cells is linked to hyperpolarization of the neurons

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, G H; Schousboe, A


    GABA has been shown to exert a neurotrophic like activity by enhancing the morphological and functional maturation of neurons. Mechanisms involved in this effect of GABA are largely unknown but since GABA has been shown to mediate a hyperpolarizing action on neurons it can be assumed...... that this action might be important. In order to investigate this possibility, the ability to mimic the trophic actions of GABA of different agents known to influence the membrane potential or the GABA gated chloride channels was studied. Hence, GABA receptor expression as well as the ultrastructure of cerebellar...... granule cells were monitored after exposure of the cells in culture to either bromide, valinomycin or picrotoxin. It was found that cells which at early developmental stages (4 days in culture) were exposed to bromide or valinomycin expressed low affinity GABA receptors similar to cells treated...

  9. Non-GABA(A)-mediated effects of lindane on neurite development and intracellular free calcium ion concentration in cultured rat hippocampal neurons. (United States)

    Ferguson, C A; Audesirk, G


    Changes in transmembrane Ca(2+) fluxes and intracellular free Ca(2+) ion concentrations ([Ca(2+)](in)) regulate many aspects of neurite development in cultured neurons. Lindane has been shown to increase [Ca(2+)](in) in several cell types. It was therefore hypothesized that lindane exposure would increase [Ca(2+)](in) and thereby alter neurite development in cultured rat hippocampal neurons. The study reported here showed that lindane (50-100 muM) increased [Ca(2+)](in) during short-term exposure (up to 4 hr); in contrast, with long-term exposure (24-48 hr) lindane (1-50 mum) decreased [Ca(2+)](in) significantly below control levels. Lindane decreased neurite initiation at high concentrations (25 mum or above). Lindane increased dendrite number at low concentrations (0.5-1 muM), but decreased dendrite number at high concentrations (50 mum or above). Lindane decreased axon and dendrite elongation and branching at 50 mum. Loading neurons with 1 mum 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA), a calcium chelator that partially 'clamps' [Ca(2+)](in), eliminated the effects of 50 mum lindane on [Ca(2+)](in) in short-term exposures. BAPTA did not significantly reverse the inhibition of neurite initiation or axonal elongation caused by 50 mum lindane. However, BAPTA partially reversed the inhibition of dendrite elongation and completely reversed the inhibition of axon and dendrite branching caused by 50 mum lindane. Therefore, some, but not all, of lindane's effects on neurite development may be due to changes in [Ca(2+)](in). Picrotoxin, a gamma-aminobutyric acid A (GABA(A))-associated chloride channel antagonist, had no effect on [Ca(2+)](in) or any parameters of neurite growth, suggesting that the effects of lindane on neurite development and [Ca(2+)](in) were not mediated through actions on GABA(A)-associated chloride channels.

  10. Differences in prefrontal cortex GABA/glutamate ratio after acute restraint stress in rats are associated with specific behavioral and neurobiological patterns. (United States)

    Drouet, J-B; Fauvelle, F; Maunoir-Regimbal, S; Fidier, N; Maury, R; Peinnequin, A; Denis, J; Buguet, A; Canini, F


    In patients suffering from stress-related pathologies and depression, frontal cortex GABA and glutamate contents are reported to decrease and increase, respectively. This suggests that the GABA and/or glutamate content may participate in pathological phenotype expression. Whether differences in frontal cortex GABA and glutamate contents would be associated with specific behavioral and neurobiological patterns remains unclear, especially in the event of exposure to moderate stress. We hypothesized that an increase in prefrontal cortex GABA/glutamate ratio would be associated with a blunted prefrontal cortex activation, an enhanced hypothalamo-pituitary-adrenocortical (HPA) axis activation and changes in behavior. Rats being restrained for 1-h were then tested in an open-field test in order to assess their behavior while under stress, and were sacrificed immediately afterward. The GABA/glutamate ratio was assessed by (1)H high-resolution magic angle spinning magnetic resonance spectroscopy ((1)H-HRMAS-MRS). The neurobiological response was evaluated through prefrontal cortex mRNA expression and plasma corticosterone levels. The stressed rats were distributed into two subgroups according to their high (H-G/g) or low (L-G/g) GABA/glutamate ratio. Compared to the L-G/g rats, the H-G/g rats exhibited a decrease in c-fos, Arc, Npas4, Nr4a2 mRNA expression suggesting blunted prefrontal cortex activation. They also showed a more pronounced stress with an enhanced rise in corticosterone, alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), creatine kinase (CK) and lactate dehydrogenase (LDH) levels, as well as behavioral disturbances with decreased locomotion speed. These changes were independent from prefrontal cortex energetic status as mammalian target of rapamycin (mTOR) and adenosine monophosphate-activated protein kinase (AMPK) pathway activities were similar in both subpopulations. The differences in GABA/glutamate ratio in the frontal cortex observed

  11. Alterations in Circulating miRNA Levels following Early-Stage Estrogen Receptor-Positive Breast Cancer Resection in Post-Menopausal Women

    DEFF Research Database (Denmark)

    Kodahl, Annette R; Zeuthen, Pernille; Binder, Harald


    design and the same qPCR profiling platform, resulting in limited agreement. CONCLUSIONS: A panel of 4 circulating miRNAs exhibited significantly altered levels following radical resection of primary ER+ breast cancers in post-menopausal women. These specific miRNAs may be involved in tumorigenesis...... these alterations were also observed in an independent data set. METHODS: Global miRNA analysis was performed on prospectively collected serum samples from 24 post-menopausal women with estrogen receptor-positive early-stage breast cancer before surgery and 3 weeks after tumor resection using global LNA...

  12. Investigating GABA and its function in platelets as compared to neurons. (United States)

    Kaneez, Fatima Shad; Saeed, Sheikh Arshad


    We have recently suggested that platelets could be used as a model for neuronal receptors. In this paper we have investigated gamma-aminobutyric acid (GABA) metabolism and GABA receptors in platelets and in cultured neurons to see whether platelets' GABA mimics neuronal GABA receptor activities. We used the ELISA technique for detecting the GABA concentration in platelet rich plasma and cultured neurons. The functional effects of GABA and its receptor ligands on platelets were determined using an aggregometer. We found that the GABA concentration is 30% lower in platelets than in neurons and in both preparations GABA was metabolized by GABA transaminase (GABA-T). GABA potentiated calcium dependent platelet aggregation with a higher value in washed platelets suspension (WPS) then in platelet rich plasma (PRP). This effect was inhibited by benzodiazepines, calcium channel blockers and the selective phosphoinositide 3-kinase antagonist Wortmannin. GABA neurotransmission is involved in most aspects of normal brain function and can be perturbed in many neuropathologic conditions. We concluded that platelets could be further developed to be used as a peripheral model to study neuronal GABAergic function and its abnormality in diseases such as epilepsy and schizophrenia. Furthermore our results indicated that PI3-kinase is involved in calcium dependent GABA induced platelet aggregation as this synergistic effect is inhibited by Wortmannin in dose dependent manner.

  13. Actions of insecticides on the insect GABA receptor complex

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez, I.; Hawkins, C.A.; Taylor, A.M.; Beadle, D.J. (School of Biological and Molecular Sciences, Oxford Polytechnic, Headington, Oxford (England))


    The actions of insecticides on the insect gamma-aminobutyric acid (GABA) receptor were investigated using (35S)t-butylbicyclophosphorothionate (( 35S)TBPS) binding and voltage-clamp techniques. Specific binding of (35S)TBPS to a membrane homogenate derived from the brain of Locusta migratoria locusts is characterised by a Kd value of 79.3 {plus minus} 2.9 nM and a Bmax value of 1770 {plus minus} 40 fmol/mg protein. (35S)TBPS binding is inhibited by mM concentrations of barbiturates and benzodiazepines. In contrast dieldrin, ivermectin, lindane, picrotoxin and TBPS are inhibitors of (35S)TBPS binding at the nanomolar range. Bicuculline, baclofen and pyrethroid insecticides have no effect on (35S)TBPS binding. These results are similar to those obtained in electrophysiological studies of the current elicited by GABA in both Locusta and Periplaneta americana central neurones. Noise analysis of the effects of lindane, TBPS, dieldrin and picrotoxin on the cockroach GABA responses reveals that these compounds decrease the variance of the GABA-induced current but have no effect on its mean open time. All these compounds, with the exception of dieldrin, significantly decrease the conductance of GABA-evoked single current.

  14. Meta-diamide insecticides acting on distinct sites of RDL GABA receptor from those for conventional noncompetitive antagonists. (United States)

    Nakao, Toshifumi; Banba, Shinich; Nomura, Michikazu; Hirase, Kangetsu


    The RDL GABA receptor is an attractive target of insecticides. Here we demonstrate that meta-diamides [3-benzamido-N-(4-(perfluoropropan-2-yl)phenyl)benzamides] are a distinct class of RDL GABA receptor antagonists showing high insecticidal activity against Spodoptera litura. We also suggest that the mode of action of the meta-diamides is distinct from that of conventional noncompetitive antagonists (NCAs), such as fipronil, picrotoxin, lindane, dieldrin, and α-endosulfan. Using a membrane potential assay, we examined the effects of the meta-diamide 3-benzamido-N-(2-bromo-4-(perfluoropropan-2-yl)-6-(trifluoromethyl)phenyl)-2-fluorobenzamide (meta-diamide 7) and NCAs on mutant Drosophila RDL GABA receptors expressed in Drosophila Mel-2 cells. NCAs had little or no inhibitory activity against at least one of the three mutant receptors (A2'S, A2'G, and A2'N), which were reported to confer resistance to NCAs. In contrast, meta-diamide 7 inhibited all three A2' mutant receptors, at levels comparable to its activity with the wild-type receptor. Furthermore, the A2'S·T6'V mutation almost abolished the inhibitory effects of all NCAs. However, meta-diamide 7 inhibited the A2'S・T6'S mutant receptor at the same level as its activity with the wild-type receptor. In contrast, a G336M mutation in the third transmembrane domain of the RDL GABA receptor abolished the inhibitory activities of meta-diamide 7, although the G336M mutation had little effect on the inhibitory activities of conventional NCAs. Molecular modeling studies also suggested that the binding site of meta-diamides was different from those of NCAs. Meta-diamide insecticides are expected to be prominent insecticides effective against A2' mutant RDL GABA receptors with a different mode of action.

  15. Increased GABA(A receptor ε-subunit expression on ventral respiratory column neurons protects breathing during pregnancy.

    Directory of Open Access Journals (Sweden)

    Keith B Hengen

    Full Text Available GABAergic signaling is essential for proper respiratory function. Potentiation of this signaling with allosteric modulators such as anesthetics, barbiturates, and neurosteroids can lead to respiratory arrest. Paradoxically, pregnant animals continue to breathe normally despite nearly 100-fold increases in circulating neurosteroids. ε subunit-containing GABA(ARs are insensitive to positive allosteric modulation, thus we hypothesized that pregnant rats increase ε subunit-containing GABA(AR expression on brainstem neurons of the ventral respiratory column (VRC. In vivo, pregnancy rendered respiratory motor output insensitive to otherwise lethal doses of pentobarbital, a barbiturate previously used to categorize the ε subunit. Using electrode array recordings in vitro, we demonstrated that putative respiratory neurons of the preBötzinger Complex (preBötC were also rendered insensitive to the effects of pentobarbital during pregnancy, but unit activity in the VRC was rapidly inhibited by the GABA(AR agonist, muscimol. VRC unit activity from virgin and post-partum females was potently inhibited by both pentobarbital and muscimol. Brainstem ε subunit mRNA and protein levels were increased in pregnant rats, and GABA(AR ε subunit expression co-localized with a marker of rhythm generating neurons (neurokinin 1 receptors in the preBötC. These data support the hypothesis that pregnancy renders respiratory motor output and respiratory neuron activity insensitive to barbiturates, most likely via increased ε subunit-containing GABA(AR expression on respiratory rhythm-generating neurons. Increased ε subunit expression may be critical to preserve respiratory function (and life despite increased neurosteroid levels during pregnancy.

  16. Neurochemical correlates of. gamma. -aminobutyrate (GABA) inhibition in cat visual cortex

    Energy Technology Data Exchange (ETDEWEB)

    Balcar, V.J.; Dreher, B. (Univ. of Sydney (Australia))


    High affinity binding of ({sup 3}H){gamma}-aminobutyric acid (GABA) to neuronal membranes from different parts of cat visual cortex was tested for sensitivity to GABA{sub A} agonists isoguvacine and THIP, GABA{sub A} antagonist SR95531 and GABA{sub B} agonist baclofen. Some of the GABA{sub A}-binding sites were found to have a very low affinity for THIP, suggesting the presence and, possibly, uneven distribution of non-synaptic GABA{sub A} receptors in cat visual cortex. There were no differences in K{sub m} and V{sub max} values of high affinity uptake of GABA and in the potency of K{sup +}-stimulated release of GABA, between primary and association cortices. Consequently, the present results indicate that despite the anatomical and physiological differences between the primary and association feline visual cortices the neurochemical characteristics of GABAergic inhibition are very similar in the two regions.

  17. GABA depolarizes immature neurons and inhibits network activity in the neonatal neocortex in vivo. (United States)

    Kirmse, Knut; Kummer, Michael; Kovalchuk, Yury; Witte, Otto W; Garaschuk, Olga; Holthoff, Knut


    A large body of evidence from in vitro studies suggests that GABA is depolarizing during early postnatal development. However, the mode of GABA action in the intact developing brain is unknown. Here we examine the in vivo effects of GABA in cells of the upper cortical plate using a combination of electrophysiological and Ca(2+)-imaging techniques. We report that at postnatal days (P) 3-4, GABA depolarizes the majority of immature neurons in the occipital cortex of anaesthetized mice. At the same time, GABA does not efficiently activate voltage-gated Ca(2+) channels and fails to induce action potential firing. Blocking GABA(A) receptors disinhibits spontaneous network activity, whereas allosteric activation of GABA(A) receptors has the opposite effect. In summary, our data provide evidence that in vivo GABA acts as a depolarizing neurotransmitter imposing an inhibitory control on network activity in the neonatal (P3-4) neocortex.

  18. Refuting the challenges of the developmental shift of polarity of GABA actions: GABA more exciting than ever! (United States)

    Ben-Ari, Yehezkel; Woodin, Melanie A; Sernagor, Evelyne; Cancedda, Laura; Vinay, Laurent; Rivera, Claudio; Legendre, Pascal; Luhmann, Heiko J; Bordey, Angelique; Wenner, Peter; Fukuda, Atsuo; van den Pol, Anthony N; Gaiarsa, Jean-Luc; Cherubini, Enrico


    DURING BRAIN DEVELOPMENT, THERE IS A PROGRESSIVE REDUCTION OF INTRACELLULAR CHLORIDE ASSOCIATED WITH A SHIFT IN GABA POLARITY: GABA depolarizes and occasionally excites immature neurons, subsequently hyperpolarizing them at later stages of development. This sequence, which has been observed in a wide range of animal species, brain structures and preparations, is thought to play an important role in activity-dependent formation and modulation of functional circuits. This sequence has also been considerably reinforced recently with new data pointing to an evolutionary preserved rule. In a recent "Hypothesis and Theory Article," the excitatory action of GABA in early brain development is suggested to be "an experimental artefact" (Bregestovski and Bernard, 2012). The authors suggest that the excitatory action of GABA is due to an inadequate/insufficient energy supply in glucose-perfused slices and/or to the damage produced by the slicing procedure. However, these observations have been repeatedly contradicted by many groups and are inconsistent with a large body of evidence including the fact that the developmental shift is neither restricted to slices nor to rodents. We summarize the overwhelming evidence in support of both excitatory GABA during development, and the implications this has in developmental neurobiology.

  19. The four human ¿-aminobutyric acid (GABA) transporters

    DEFF Research Database (Denmark)

    Kvist, Trine; Christiansen, Bolette; Jensen, Anders Asbjørn;


    , we perform the first elaborate pharmacological characterization of all four human GAT subtypes. We conduct the experiments in parallel in a [3H]GABA uptake assay using 14 standard GAT substrates and inhibitors. This setup enables direct comparison of the absolute values of inhibitory activities......, no subtype selective ligands have been reported for the three remaining GATs. Given the potential therapeutic relevance of the individual GAT subtypes, a search for novel structures displaying selectivities for specific GAT subtypes is important. In this study, we validate our [3H]GABA uptake assay for use...... in high throughput screening. We find that the assay is categorized by high Z'-factors (Z' > 0.5) for all four GAT subtypes, demonstrating that the assay is excellent for a high throughput screen. This [3H]GABA uptake assay therefore enables future high through put screening of compound libraries...

  20. GABA-B receptor activation and conflict behavior

    Energy Technology Data Exchange (ETDEWEB)

    Ketelaars, C.E.J.; Bollen, E.L.; Rigter, H.; Bruinvels, J.


    Baclofen and oxazepam enhance extinction of conflict behavior in the Geller-Seifter test while baclofen and diazepam release punished behavior in Vogel's conflict test. In order to investigate the possibility that the effect of the selective GABA-B receptor agonist baclofen is mediated indirectly via the GABA-A/benzodiazepine receptor complex, the effect of pretreatment of rats with baclofen on (/sup 3/H)-diazepam binding to washed and unwashed cortical and cerebellar membranes of rats has been studied. Baclofen pretreatment increase Bmax in washed cerebellar membranes when bicuculline was present in the incubation mixture. No effect was seen in cortical membranes. The present results render it unlikely that the effect of baclofen on extinction of conflict behavior and punished drinking is mediated via the GABA-A/benzodiazepine receptor complex. 50 references, 1 figure, 4 tables.

  1. GABA(B) receptor activation in the ventral tegmental area inhibits the acquisition and expression of opiate-induced motor sensitization. (United States)

    Leite-Morris, Kimberly A; Fukudome, Eugene Y; Shoeb, Marwa H; Kaplan, Gary B


    Opiate-induced motor sensitization refers to the progressive and enduring motor response that develops after intermittent drug administration, and results from neuroadaptive changes in ventral tegmental area (VTA) and nucleus accumbens (NAc) neurons. Repeated activation of mu-opioid receptors localized on gamma-aminobutyric acid (GABA) neurons in the VTA enhances dopaminergic cell activity and stimulates dopamine release in the nucleus accumbens. We hypothesize that GABA(B) receptor agonist treatment in the VTA blocks morphine-induced motor stimulation, motor sensitization, and accumbal Fos immunoreactivity by inhibiting the activation of dopaminergic neurons. First, C57BL/6 mice were coadministered a single subcutaneous injection of morphine with intra-VTA baclofen, a GABA(B) receptor agonist. Baclofen produced a dose-dependent inhibition of opiate-induced motor stimulation that was attenuated by 2-hydroxysaclofen, a GABA(B) receptor antagonist. Next, morphine was administered on days 1, 3, 5, and 9 and mice demonstrated sensitization to its motor stimulant effects and concomitant induction of Fos immunoreactivity in the NAc shell (NAcS) but not NAc core. Intra-VTA baclofen administered during morphine pretreatment blocked the acquisition of morphine-induced motor sensitization and Fos activation in the NAcS. Intra-VTA baclofen administered only on day 9 blocked the expression of morphine-induced motor sensitization and Fos activation in the NAcS. A linear relationship was found between morphine-induced motor activity and accumbal Fos in single- and repeated-dose treatment groups. In conclusion, GABA(B) receptor stimulation in the VTA blocked opiate-induced motor stimulation and motor sensitization by inhibiting the activation of NAcS neurons. GABA(B) receptor agonists may be useful pharmacological treatments in altering the behavioral effects of opiates.

  2. Lung adenocarcinoma of never smokers and smokers harbor differential regions of genetic alteration and exhibit different levels of genomic instability.

    Directory of Open Access Journals (Sweden)

    Kelsie L Thu

    Full Text Available Recent evidence suggests that the observed clinical distinctions between lung tumors in smokers and never smokers (NS extend beyond specific gene mutations, such as EGFR, EML4-ALK, and KRAS, some of which have been translated into targeted therapies. However, the molecular alterations identified thus far cannot explain all of the clinical and biological disparities observed in lung tumors of NS and smokers. To this end, we performed an unbiased genome-wide, comparative study to identify novel genomic aberrations that differ between smokers and NS. High resolution whole genome DNA copy number profiling of 69 lung adenocarcinomas from smokers (n = 39 and NS (n = 30 revealed both global and regional disparities in the tumor genomes of these two groups. We found that NS lung tumors had a greater proportion of their genomes altered than those of smokers. Moreover, copy number gains on chromosomes 5q, 7p, and 16p occurred more frequently in NS. We validated our findings in two independently generated public datasets. Our findings provide a novel line of evidence distinguishing genetic differences between smoker and NS lung tumors, namely, that the extent of segmental genomic alterations is greater in NS tumors. Collectively, our findings provide evidence that these lung tumors are globally and genetically different, which implies they are likely driven by distinct molecular mechanisms.

  3. Role of GABA-active neurosteroids in the efficacy of metyrapone against cocaine addiction. (United States)

    Schmoutz, Christopher D; Guerin, Glenn F; Goeders, Nicholas E


    Previous research has demonstrated a complicated role for stress and HPA axis activation in potentiating various cocaine-related behaviors in preclinical models of drug dependence. However, the investigation of several antiglucocorticoid therapies has yielded equivocal results in reducing cocaine-related behaviors, possibly because of varying mechanisms of actions. Specifically, research suggests that metyrapone (a corticosterone synthesis inhibitor) may reduce cocaine self-administration in rats via a nongenomic, extra-adrenal mechanism without altering plasma corticosterone. In the current experiments, male rats were trained to self-administer cocaine infusions and food pellets in a multiple, alternating schedule of reinforcement. Metyrapone pretreatment dose-dependently decreased cocaine self-administration as demonstrated previously. Pharmacological inhibition of neurosteroid production by finasteride had significant effects on cocaine self-administration, regardless of metyrapone pretreatment. However, metyrapone's effects on cocaine self-administration were significantly attenuated with bicuculline pretreatment, suggesting a role for GABA-active neurosteroids in cocaine-reinforced behaviors. In vitro binding data also confirmed that metyrapone does not selectively bind to GABA-related proteins. The results of these experiments support the hypothesis that metyrapone may increase neurosteroidogenesis to produce effects on cocaine-related behaviors.

  4. Celsr3 is required for normal development of GABA circuits in the inner retina.

    Directory of Open Access Journals (Sweden)

    Alaron Lewis


    Full Text Available The identity of the specific molecules required for the process of retinal circuitry formation is largely unknown. Here we report a newly identified zebrafish mutant in which the absence of the atypical cadherin, Celsr3, leads to a specific defect in the development of GABAergic signaling in the inner retina. This mutant lacks an optokinetic response (OKR, the ability to visually track rotating illuminated stripes, and develops a super-normal b-wave in the electroretinogram (ERG. We find that celsr3 mRNA is abundant in the amacrine and ganglion cells of the retina, however its loss does not affect synaptic lamination within the inner plexiform layer (IPL or amacrine cell number. We localize the ERG defect pharmacologically to a late-stage disruption in GABAergic modulation of ON-bipolar cell pathway and find that the DNQX-sensitive fast b1 component of the ERG is specifically affected in this mutant. Consistently, we find an increase in GABA receptors on mutant ON-bipolar terminals, providing a direct link between the observed physiological changes and alterations in GABA signaling components. Finally, using blastula transplantation, we show that the lack of an OKR is due, at least partially, to Celsr3-mediated defects within the brain. These findings support the previously postulated inner retina origin for the b1 component and reveal a new role for Celsr3 in the normal development of ON visual pathway circuitry in the inner retina.

  5. Biphasic Alteration of the Inhibitory Synapse Scaffold Protein Gephyrin in Early and Late Stages of an Alzheimer Disease Model. (United States)

    Kiss, Eva; Gorgas, Karin; Schlicksupp, Andrea; Groß, Dagmar; Kins, Stefan; Kirsch, Joachim; Kuhse, Jochen


    The pathogenesis of Alzheimer disease (AD) is thought to begin many years before the diagnosis of dementia. Accumulating evidence indicates the involvement of GABAergic neurotransmission in the physiopathology of AD. However, in comparison to excitatory synapses, the structural and functional alterations of inhibitory synapses in AD are less well characterized. We studied the expression and distribution of proteins specific for inhibitory synapses in hippocampal areas of APPPS1 mice at different ages. Interestingly, by immunoblotting and confocal fluorescence microscopy, we disclosed a robust increase in the expression of gephyrin, an organizer of ligand-gated ion channels at inhibitory synapses in hippocampus CA1 and dentate gyrus of young presymptomatic APPPS1 mice (1 to 3 months) as compared to controls. The postsynaptic γ2-GABA(A)-receptor subunit and the presynaptic vesicular inhibitory amino acid transporter protein showed similar expression patterns. In contrast, adult transgenic animals (12 months) displayed decreased levels of these proteins in comparison to wild type in hippocampus areas devoid of amyloid plaques. Within most plaques, strong gephyrin immunoreactivity was detected, partially colocalizing with vesicular amino acid transporter and GABA(A)-receptor γ2 subunit immunoreactivities. Our results indicate a biphasic alteration in expression of hippocampal inhibitory synapse components in AD. Altered inhibition of neurotransmission might be an early prognostic marker and might even be involved in the pathogenesis of AD.

  6. Melanogenesis stimulation in B16-F10 melanoma cells induces cell cycle alterations, increased ROS levels and a differential expression of proteins as revealed by proteomic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Elizabeth S.; Kawahara, Rebeca [Departamento de Bioquimica e Biologia Molecular, Setor de Ciencias Biologicas, Universidade Federal do Parana, P.O. Box 19046, CEP 81531-990, Curitiba, PR (Brazil); Kadowaki, Marina K. [Universidade Estadual do Oeste do Parana, Cascavel, PR (Brazil); Amstalden, Hudson G.; Noleto, Guilhermina R.; Cadena, Silvia Maria S.C.; Winnischofer, Sheila M.B. [Departamento de Bioquimica e Biologia Molecular, Setor de Ciencias Biologicas, Universidade Federal do Parana, P.O. Box 19046, CEP 81531-990, Curitiba, PR (Brazil); Martinez, Glaucia R., E-mail: [Departamento de Bioquimica e Biologia Molecular, Setor de Ciencias Biologicas, Universidade Federal do Parana, P.O. Box 19046, CEP 81531-990, Curitiba, PR (Brazil)


    Considering that stimulation of melanogenesis may lead to alterations of cellular responses, besides melanin production, our main goal was to study the cellular effects of melanogenesis stimulation of B16-F10 melanoma cells. Our results show increased levels of the reactive oxygen species after 15 h of melanogenesis stimulation. Following 48 h of melanogenesis stimulation, proliferation was inhibited (by induction of cell cycle arrest in the G1 phase) and the expression levels of p21 mRNA were increased. In addition, melanogenesis stimulation did not induce cellular senescence. Proteomic analysis demonstrated the involvement of proteins from other pathways besides those related to the cell cycle, including protein disulfide isomerase A3, heat-shock protein 70, and fructose biphosphate aldolase A (all up-regulated), and lactate dehydrogenase (down-regulated). In RT-qPCR experiments, the levels of pyruvate kinase M2 mRNA dropped, whereas the levels of ATP synthase (beta-F1) mRNA increased. These data indicate that melanogenesis stimulation of B16-F10 cells leads to alterations in metabolism and cell cycle progression that may contribute to an induction of cell quiescence, which may provide a mechanism of resistance against cellular injury promoted by melanin synthesis. -- Highlights: Black-Right-Pointing-Pointer Melanogenesis stimulation by L-tyrosine+NH{sub 4}Cl in B16-F10 melanoma cells increases ROS levels. Black-Right-Pointing-Pointer Melanogenesis inhibits cell proliferation, and induced cell cycle arrest in the G1 phase. Black-Right-Pointing-Pointer Proteomic analysis showed alterations in proteins of the cell cycle and glucose metabolism. Black-Right-Pointing-Pointer RT-qPCR analysis confirmed alterations of metabolic targets after melanogenesis stimulation.

  7. Selective mGAT2 (BGT-1) GABA Uptake Inhibitor

    DEFF Research Database (Denmark)

    Vogensen, Stine Byskov; Jørgensen, Lars; Madsen, Karsten Kirkegaard;


    β-Amino acids sharing a lipophilic diaromatic side chain were synthesized and characterized pharmacologically on mouse GABA transporter subtypes mGAT1−4. The parent amino acids were also characterized. Compounds 13a, 13b, and 17b displayed more than 6-fold selectivity for mGAT2 over mGAT1. Compound...... 17b displayed anticonvulsive properties inferring a role of mGAT2 in epileptic disorders. These results provide new neuropharmacological tools and a strategy for designing subtype selective GABA transport inhibitors....

  8. [GABA, a key transmitter for fetal brain maturation]. (United States)

    Ben-Ari, Yehezkel


    GABA, the principal inhibitory transmitter excites immature neurons in all animal species studied. This is due to the higher intracellular concentration of chloride at early developmental stages. Excitatory actions of GABA play an important action in brain maturation. Recent observations also suggest an abrupt shift during delivery that exerts a neuro-protective action contributing to reduce the sequels of trauma and anoxic episodes. These observations have important clinical implications in relation to delivery associated insults but also preterm delivery and more generally consumption of agents during gestation.

  9. Fast detection of extrasynaptic GABA with a whole-cell sniffer

    DEFF Research Database (Denmark)

    Christensen, Rasmus K; Petersen, Anders V; Schmitt, Nicole;


    . Ambient GABA is essential for adjusting the excitability of neurons. However, due to the lack of suitable methods, little is known about its dynamics. Here we describe a new technique that allows detection of GABA transients and measurement of the steady state GABA concentration with high spatial...

  10. Cloning and characterization of a functional human ¿-aminobutyric acid (GABA) transporter, human GAT-2

    DEFF Research Database (Denmark)

    Christiansen, Bolette; Meinild, Anne-Kristine; Jensen, Anders A.


    and dependent on both Na(+) and Cl(-). Pharmacologically the transporter is distinct from the other human GABA transporters and similar to rat GAT-2 and mouse GAT3 with high sensitivity toward GABA and beta-alanine. Furthermore the GABA transport inhibitor (S)-SNAP-5114 displayed some inhibitory activity...

  11. Aerobic bacterial microbiota of the conjunctiva in diabetic patients with normal and altered glycated hemoglobin levels in two regions in Brazil

    Directory of Open Access Journals (Sweden)

    Natalia Pimentel Moreno


    Full Text Available Purpose: To study the aerobic bacterial microbiota of the conjunctiva in diabetic patients with regard to the management of diabetes, assessed using glycated hemoglobin levels. Methods: A cross-sectional study was conducted using conjunctival smears of diabetic patients from both sexes and with different ages, residing in two different Brazilian cities (Sorocaba and Rio Branco. A control group of non-diabetic patients was also included. The diabetic patients were considered to have controlled diabetes when their glycated hemoglobin level was ≤7% and blood glucose level was ≤126 mg/dL. Patients with non-controlled diabetes were those with glycated hemoglobin levels >7% and blood glucose levels >126 mg/dL. The samples obtained were inoculated in Brain-Heart Infusion broth and in culture media for aerobic bacteria (blood and chocolate agars; bacterial growth was evaluated in a microbiology laboratory. Results: A total of 120 eyes of 120 patients were included in the present study. The percentage of cultures in which bacterial growth was observed was greater in diabetic patients, although the difference was not statistically significant (p=0.103. There was a greater trend toward bacterial growth in the conjunctiva of diabetic patients with altered fasting blood glucose. There was no difference in the frequency of bacterial growth on the conjunctiva between diabetic patients with normal or altered glycated hemoglobin levels. In Sorocaba, conjunctival bacterial growth was similar to that observed in Rio Branco. The microorganism most frequently detected in the present study was Staphylococcus epidermidis, followed by Staphylococcus aureus, Proteus mirabilis, and Escherichia coli. Conclusion: There was no difference between diabetic patients with normal or altered glycated hemoglobin levels. The microorganisms found were similar to those found in studies investigating the conjunctival bacterial flora of diabetic and non-diabetic patients.

  12. Altered Levels of MicroRNA-9, -206, and -132 in Spinal Muscular Atrophy and Their Response to Antisense Oligonucleotide Therapy. (United States)

    Catapano, Francesco; Zaharieva, Irina; Scoto, Mariacristina; Marrosu, Elena; Morgan, Jennifer; Muntoni, Francesco; Zhou, Haiyan


    The identification of noninvasive biomarkers to monitor the disease progression in spinal muscular atrophy (SMA) is becoming increasingly important. MicroRNAs (miRNAs) regulate gene expression and are implicated in the pathogenesis of neuromuscular diseases, including motor neuron degeneration. In this study, we selectively characterized the expression of miR-9, miR-206, and miR-132 in spinal cord, skeletal muscle, and serum from SMA transgenic mice, and in serum from SMA patients. A systematic analysis of miRNA expression was conducted in SMA mice with different disease severities (severe type I-like and mild type III-like) at different disease stages (pre-, mid-, and late-symptomatic stages), and in morpholino antisense oligonucleotide-treated mice. There was differential expression of all three miRNAs in spinal cord, skeletal muscle and serum samples in SMA mice. Serum miRNAs were altered prior to the changes in spinal cord and skeletal muscle at the presymptomatic stage. The altered miR-132 levels in spinal cord, muscle, and serum transiently reversed to normal level after a single-dose morpholino antisense oligomer PMO25 treatment in SMA mice. We also confirmed a significant alteration of miR-9 and miR-132 level in serum samples from SMA patients. Our study indicates the potential of developing miRNAs as noninvasive biomarkers in SMA.

  13. GABA inhibition of luminescence from lantern shark (Etmopterus spinax) photophores. (United States)

    Claes, Julien M; Krönström, Jenny; Holmgren, Susanne; Mallefet, Jérôme


    Photogenic organs (photophores) of the velvet belly lantern shark (Etmopterus spinax) are under hormonal control, since melatonin (MT) and prolactin (PRL) trigger luminescence while α-melanocyte-stimulating hormone (α-MSH) prevents this light to be emitted. A recent study supported, however, the presence of numerous nerve fibres in the photogenic tissue of this shark. Immunohistochemical and pharmacological results collected in this work support these nerve fibres to be inhibitory GABAergic nerves since (i) GABA immunoreactivity was detected inside the photogenic tissue, where previous labelling detected the nerve fibre structures and (ii) GABA was able to inhibit MT and PRL-induced luminescence, which was on the other hand increased by the GABA(A) antagonist bicuculline (BICU). In addition, we also demonstrated that BICU can induce light per se by provoking pigment retraction in the pigmented cells composing the iris-like structure of the photophore, attaining, however, only about 10% of hormonally induced luminescence intensity at 10(-3)mol L(-1). This strongly supports that a GABA inhibitory tonus controls photophore "aperture" in the photogenic tissue of E. spinax but also that MT and PRL have more than one target cell type in the photophores.

  14. Neurofibromin Regulation of ERK Signaling Modulates GABA Release and Learning

    NARCIS (Netherlands)

    Y. Cui (Yijun); R.M. Costa (Rui); G.G. Murphy (Geoffrey); Y. Elgersma (Ype); Y. Zhu (Yuan); D.H. Gutmann (David); L.F. Parada (Luis); I. Mody (Istvan); A.J. Silva (Alcino)


    textabstractWe uncovered a role for ERK signaling in GABA release, long-term potentiation (LTP), and learning, and show that disruption of this mechanism accounts for the learning deficits in a mouse model for learning disabilities in neurofibromatosis type I (NF1). Our results demonstrate that neur

  15. Structure activity relationship of selective GABA uptake inhibitors

    DEFF Research Database (Denmark)

    Vogensen, Stine Byskov; Jørgensen, Lars; Madsen, Karsten K;


    A series of β-amino acids with lipophilic diaromatic side chain was synthesized and characterized pharmacologically on mouse γ-amino butyric acid (GABA) transporter subtypes mGAT1-4 in order to investigate structure activity relationships (SAR) for mGAT2 (corresponding to hBGT-1). Variation...

  16. Single rodent mesohabenular axons release glutamate and GABA (United States)

    Root, David H.; Mejias-Aponte, Carlos; Zhang, Shiliang; Wang, Huiling; Hoffman, Alexander F.; Lupica, Carl R.; Morales, Marisela


    The lateral habenula (LHb) is involved in reward, aversion, addiction, and depression, through descending interactions with several brain structures, including the ventral tegmental area (VTA). VTA provides reciprocal inputs to LHb, but their actions are unclear. Here we show that the majority of rat and mouse VTA neurons innervating LHb co-express markers for both glutamate-signaling (vesicular glutamate transporter 2, VGluT2) and GABA-signaling (glutamate decarboxylase, GAD; and vesicular GABA transporter, VGaT). A single axon from these mesohabenular neurons co-expresses VGluT2-protein and VGaT-protein, and surprisingly establishes symmetric and asymmetric synapses on LHb neurons. In LHb slices, light activation of mesohabenular fibers expressing channelrhodopsin-2 (ChR2) driven by VGluT2 or VGaT promoters elicits release of both glutamate and GABA onto single LHb neurons. In vivo light-activation of mesohabenular terminals inhibits or excites LHb neurons. Our findings reveal an unanticipated type of VTA neuron that co-transmits glutamate and GABA, and provides the majority of mesohabenular inputs. PMID:25242304

  17. Synthesis and proton NMR spectroscopy of intra-vesicular gamma-aminobutyric acid (GABA). (United States)

    Wang, Luke Y-J; Tong, Rong; Kohane, Daniel S


    We report the synthesis of vesicles containing gamma-aminobutyric acid (GABA), and their proton nuclear magnetic resonance ((1)H NMR) spectra. These vesicles were constructed to more closely mimic the intracellular environment wherein GABA exists. For this study, these GABA-containing vesicles were examined under (1)H NMR as a potential platform for future studies on the differences between aqueous phantoms, ex vivo brain extracts, and in vivo magnetic resonance spectroscopy results. We found that intra-vesicular GABA faithfully yielded the chemical shifts and J-coupling constants of free aqueous GABA, alongside the chemical shift signals of the vesicle wall.

  18. Antidepressant Effects of Electroconvulsive Therapy Unrelated to the Brain's Functional Network Connectivity alterations at an Individual Level (United States)

    Chen, Guang-Dong; Ji, Feng; Li, Gong-Ying; Lyu, Bo-Xuan; Hu, Wei; Zhuo, Chuan-Jun


    Background: Electroconvulsive therapy (ECT) can alleviate the symptoms of treatment-resistant depression (TRD). Functional network connectivity (FNC) is a newly developed method to investigate the brain's functional connectivity patterns. The first aim of this study was to investigate FNC alterations between TRD patients and healthy controls. The second aim was to explore the relationship between the ECT treatment response and pre-ECT treatment FNC alterations in individual TRD patients. Methods: This study included 82 TRD patients and 41 controls. Patients were screened at baseline and after 2 weeks of treatment with a combination of ECT and antidepressants. Group information guided-independent component analysis (GIG-ICA) was used to compute subject-specific functional networks (FNs). Grassmann manifold and step-wise forward component selection using support vector machines were adopted to perform the FNC measure and extract the functional networks' connectivity patterns (FCP). Pearson's correlation analysis was used to calculate the correlations between the FCP and ECT response. Results: A total of 82 TRD patients in the ECT group were successfully treated. On an average, 8.50 ± 2.00 ECT sessions were conducted. After ECT treatment, only 42 TRD patients had an improved response to ECT (the Hamilton scores reduction rate was more than 50%), response rate 51%. 8 FNs (anterior and posterior default mode network, bilateral frontoparietal network, audio network, visual network, dorsal attention network, and sensorimotor network) were obtained using GIG-ICA. We did not found that FCPs were significantly different between TRD patients and healthy controls. Moreover, the baseline FCP was unrelated to the ECT treatment response. Conclusions: The FNC was not significantly different between the TRD patients and healthy controls, and the baseline FCP was unrelated to the ECT treatment response. These findings will necessitate that we modify the experimental scheme to

  19. GABA (γ-aminobutyric acid production, antioxidant activity in some germinated dietary seeds and the effect of cooking on their GABA content

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    Kasarin TIANSAWANG


    Full Text Available Abstract Germinated grains have been known as sources of Gamma-aminobutyric acid (GABA that provide beneficial effects for human health. This study was aimed to investigate GABA production, dietary fiber, antioxidant activity, and the effect of cooking on GABA loss in germinated legumes and sesame. The highest GABA content was found in germinated mung bean, (0.8068 g kg-1, 24 h incubation followed by germinated soybean, germinated black bean and soaked sesame. Beside GABA, dietary fiber content also increased in all grains during germination where the insoluble dietary fiber fractions were always found in higher proportions to soluble dietary fiber fractions. Our results also confirmed that germinated mung bean is a rich source of GABA and dietary fibers. Microwave cooking resulted in the smallest loss of GABA in mung bean and sesame, while steaming led to the least GABA content loss in soybean and black bean. Therefore microwave cooking and steaming are the most recommended cooking processes to preserve GABA in germinated legumes and sesame.

  20. Spatial distributions of GABA receptors and local inhibition of Ca2+ transients studied with GABA uncaging in the dendrites of CA1 pyramidal neurons.

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    Yuya Kanemoto

    Full Text Available GABA (γ-amino-butylic acid-mediated inhibition in the dendrites of CA1 pyramidal neurons was characterized by two-photon uncaging of a caged-GABA compound, BCMACM-GABA, and one-photon uncaging of RuBi-GABA in rat hippocampal slice preparations. Although we found that GABA(A-mediated currents were diffusely distributed along the dendrites, currents elicited at the branch points of the apical dendritic trunk were approximately two times larger than those elsewhere in the dendrite. We examined the inhibitory action of the GABA-induced currents on Ca(2+ transients evoked with a single back-propagating action potential (bAP in oblique dendrites. We found that GABA uncaging selectively inhibited the Ca(2+ transients in the region adjacent (20 µm. Our data indicate that GABA inhibition results in spatially confined inhibition of Ca(2+ transients shortly after bAP, and suggest that this effect is particularly potent at the dendritic branch points where GABA receptors cluster.

  1. GABA(A) receptor subtype selective cognition enhancers. (United States)

    Maubach, Karen


    Currently the treatment of Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI) is largely unrealised, with no preventive or curative therapies. The marketed acetylcholinesterase inhibitors (eg. donepezil, Aricept) are directed toward temporary symptomatic relief from impaired cognition, but have prominent adverse effects with minimal efficacy. In pursuit of novel cognition enhancers, the observation that classical benzodiazepines (BZ, eg. diazepam) are amnesic, coupled with the preservation of GABA(A) receptors in brain areas most affected by AD, highlighted the GABA(A) receptor as a potential therapeutic target. In contrast to the amnesic BZ agonists, the BZ inverse agonists (eg. DMCM) which attenuate GABA(A) receptor function, have been shown to improve performance in animal models of learning and memory. Unfortunately, such non-selective ligands also induce anxiety and convulsions. More recently, novel ligands have been developed (eg. 6,6-dimethyl-3-(2-hydroxyethyl)thio-1-(thiazol-2-yl)-6,7-dihydro-2-benzothiophen-4(5H)-one) that demonstrate binding selectivity and high inverse agonism for the alpha5 GABA(A) receptor subtype, which is preferentially located in the hippocampus, a region of the brain associated with learning and memory. Pre-clinical results are encouraging, since these alpha5 selective inverse agonists enhance memory in animal models, such as spatial learning in the Morris water-maze, but are devoid of the adverse effects associated with activity at other GABA(A) receptor subtypes in other brain regions. If the efficacy and safety profiles of alpha5 inverse agonists in humans prove to be similar to those seen in pre-clinical studies, these compounds would offer significant benefit to AD and MCI patients.

  2. GABA mediated excitation in immature rat CA3 hippocampal neurons. (United States)

    Cherubini, E; Rovira, C; Gaiarsa, J L; Corradetti, R; Ben Ari, Y


    Intracellular recordings from rat hippocampal neurons in vitro during the first postnatal week revealed the presence of spontaneous giant depolarizing potentials (GDPs). These were generated by the synchronous discharge of a population of neurons. GDPs reversed polarity at -27 and -51 mV when recorded with KCl or K-methylsulphate filled electrodes, respectively. GDPs were blocked by the GABAA receptor antagonist bicuculline (10 microM). Iontophoretic or bath applications of GABA (10-300 microM) in the presence of tetrodotoxin (1 microM), induced a membrane depolarization or in voltage clamp experiments an inward current which reversed polarity at the same potential as GDPs. The response to GABA was blocked in a non-competitive manner by bicuculline (10 microM) and did not desensitize. GABA mediated GDPs were presynaptically modulated by N-methyl-D-aspartate (NMDA) and non-NMDA receptors. Their frequency was reduced or blocked by NMDA receptor antagonists and by the rather specific non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). The frequency of GDPs was enhanced by glycine and D-serine (10-30 microM) in a strychnine insensitive manner. This effect was blocked by AP-5, suggesting that it was mediated by the allosteric modulatory site of the NMDA receptor. These observations suggest that most of the 'excitatory' drive in immature neurons is mediated by GABA acting on GABAA receptors; furthermore excitatory amino acids modulate the release of GABA by a presynaptic action on GABAergic interneurons.

  3. Acute desensitization of presynaptic GABA(B)-mediated inhibition and induction of epileptiform discharges in the neonatal rat hippocampus

    NARCIS (Netherlands)

    Tosetti, P; Bakels, R; Colin-Le Brun, [No Value; Ferrand, N; Gaiarsa, JL; Caillard, O


    The consequences of sustained activation of GABA(B) receptors on GABA(B)-mediated inhibition and network activity were investigated in the neonatal rat hippocampus using whole-cell and extracellular field recordings. GABA(B)-mediated presynaptic control of gamma-aminobutyric acid (GABA) release prog

  4. The role of GABA in the regulation of GnRH neurons

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    Miho eWatanabe


    Full Text Available Gonadotropin-releasing hormone (GnRH neurons form the final common pathway for the central regulation of reproduction. Gamma-amino butyric acid (GABA has long been implicated as one of the major players in the regulation of GnRH neurons. Although GABA is typically an inhibitory neurotransmitter in the mature adult central nervous system, most mature GnRH neurons show the unusual characteristic of being excited by GABA. While many reports have provided much insight into the contribution of GABA to the activity of GnRH neurons, the precise physiological role of the excitatory action of GABA on GnRH neurons remains elusive. This brief review presents the current knowledge of the role of GABA signaling in GnRH neuronal activity. We also discuss the modulation of GABA signaling by neurotransmitters and neuromodulators and the functional consequence of GABAergic inputs to GnRH neurons in both the physiology and pathology of reproduction.

  5. Photorelease of GABA with visible light using an inorganic caging group

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    Emiliano Rial Verde


    Full Text Available We describe the selective photorelease of γ-amino butyric acid (GABA with a novel caged-GABA compound that uses a ruthenium complex as photosensor. This compound (“RuBi-GABA” can be excited with visible wavelengths, providing greater tissue penetration, less photo-toxicity, and faster photorelease kinetics than currently used UV light-sensitive caged compounds. Using pyramidal neurons from neocortical brain slices, we show that RuBi-GABA uncaging induces GABA-A receptor-mediated responses, has no detectable side effects on endogenous GABAergic and glutamatergic receptors and generates responses with kinetics and spatial resolution comparable to the best caged GABA compounds presently available. Finally, we illustrate two potential applications of RuBi-GABA uncaging: GABA receptor mapping, and optical silencing of neuronal firing.

  6. Are presynaptic GABA-Cρ2 receptors involved in anti-nociception? (United States)

    Tadavarty, R; Hwang, J; Rajput, P S; Soja, P J; Kumar, U; Sastry, B R


    We investigated the anti-nociceptive effects of GABA-C receptors in the central nervous system. Intracisternal injection of CACA, a GABA-C receptor agonist or isoguvacine, a GABA-A receptor agonist, significantly increased the tail-withdrawal latency. TPMPA, a GABA-C receptor antagonist blocked the effects of CACA but not isoguvacine indicating that GABA-C receptors are involved in regulating pain. Further, double-labelled immunofluorescence studies revealed that GABA-Cρ2 receptors are expressed presynaptically in the spinal dorsal horn, especially, substantia gelatinosa, a region that has been previously implicated in analgesia by regulating nociceptive inflow. These data provide a provenance for future work looking at presynaptic spinal GABA-C receptors in the control of nociception.

  7. An autonomous circadian clock in the inner mouse retina regulated by dopamine and GABA.

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    Guo-Xiang Ruan


    Full Text Available The influence of the mammalian retinal circadian clock on retinal physiology and function is widely recognized, yet the cellular elements and neural regulation of retinal circadian pacemaking remain unclear due to the challenge of long-term culture of adult mammalian retina and the lack of an ideal experimental measure of the retinal circadian clock. In the current study, we developed a protocol for long-term culture of intact mouse retinas, which allows retinal circadian rhythms to be monitored in real time as luminescence rhythms from a PERIOD2::LUCIFERASE (PER2::LUC clock gene reporter. With this in vitro assay, we studied the characteristics and location within the retina of circadian PER2::LUC rhythms, the influence of major retinal neurotransmitters, and the resetting of the retinal circadian clock by light. Retinal PER2::LUC rhythms were routinely measured from whole-mount retinal explants for 10 d and for up to 30 d. Imaging of vertical retinal slices demonstrated that the rhythmic luminescence signals were concentrated in the inner nuclear layer. Interruption of cell communication via the major neurotransmitter systems of photoreceptors and ganglion cells (melatonin and glutamate and the inner nuclear layer (dopamine, acetylcholine, GABA, glycine, and glutamate did not disrupt generation of retinal circadian PER2::LUC rhythms, nor did interruption of intercellular communication through sodium-dependent action potentials or connexin 36 (cx36-containing gap junctions, indicating that PER2::LUC rhythms generation in the inner nuclear layer is likely cell autonomous. However, dopamine, acting through D1 receptors, and GABA, acting through membrane hyperpolarization and casein kinase, set the phase and amplitude of retinal PER2::LUC rhythms, respectively. Light pulses reset the phase of the in vitro retinal oscillator and dopamine D1 receptor antagonists attenuated these phase shifts. Thus, dopamine and GABA act at the molecular level of PER

  8. Positive Allosteric Modulator of GABA Lowers BOLD Responses in the Cingulate Cortex.

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    Susanna A Walter

    Full Text Available Knowledge about the neural underpinnings of the negative blood oxygen level dependent (BOLD responses in functional magnetic resonance imaging (fMRI is still limited. We hypothesized that pharmacological GABAergic modulation attenuates BOLD responses, and that blood concentrations of a positive allosteric modulator of GABA correlate inversely with BOLD responses in the cingulate cortex. We investigated whether or not pure task-related negative BOLD responses were co-localized with pharmacologically modulated BOLD responses. Twenty healthy adults received either 5 mg diazepam or placebo in a double blind, randomized design. During fMRI the subjects performed a working memory task. Results showed that BOLD responses in the cingulate cortex were inversely correlated with diazepam blood concentrations; that is, the higher the blood diazepam concentration, the lower the BOLD response. This inverse correlation was most pronounced in the pregenual anterior cingulate cortex and the anterior mid-cingulate cortex. For subjects with diazepam plasma concentration > 0.1 mg/L we observed negative BOLD responses with respect to fixation baseline. There was minor overlap between cingulate regions with task-related negative BOLD responses and regions where the BOLD responses were inversely correlated with diazepam concentration. We interpret that the inverse correlation between the BOLD response and diazepam was caused by GABA-related neural inhibition. Thus, this study supports the hypothesis that GABA attenuates BOLD responses in fMRI. The minimal overlap between task-related negative BOLD responses and responses attenuated by diazepam suggests that these responses might be caused by different mechanisms.

  9. Association of Parkinson's disease with altered serum levels of lead and transition metals among South Indian subjects. (United States)

    Kumudini, Nadella; Uma, Addepally; Devi, Yalavarthy Prameela; Naushad, Shaik Mohammad; Mridula, Rukmini; Borgohain, Rupam; Kutala, Vijay Kumar


    Several epidemiologic studies have suggested an association between the Parkinson's disease (PD) and exposure to heavy metals, such as lead, iron, copper, manganese, etc. A growing body of evidence suggests that heavy metals stimulate free radical formation in the brain and can lead to neurodegeneration. In the present study, we investigated whether such association exists in PD cases from rural and urban areas in our study population. The plasma levels of copper, iron, manganese and lead in PD cases (n = 150) and controls (n = 170) were determined by inductively coupled plasma mass spectrometry (ICP-MS) and correlated with the oxidative stress markers like malondialdehyde (MDA), protein carbonyl and total glutathione. Results indicated significant increase in the levels of copper (17.73 +/- 4.48 vs. 13.0 + 3.22 ng/ml) and iron (554.4 +/- 123.8 vs. 421.7 +/- 126.1 ng/ml) in PD cases compared to controls, whereas no significant differences in the levels of manganese and lead were observed. Further, the data based on urban or rural residence showed that plasma copper, iron, manganese levels were comparatively higher in rural subjects, whereas plasma lead levels were significantly higher in urban subjects. Increased plasma iron showed positive correlation with marker of lipid peroxidation (MDA), suggesting that increased iron levels induced oxidative stress in PD. These results substantiated the earlier observations about the role of environmental exposure and metal-induced oxidative stress in the etiology of PD.

  10. Cell-attached recordings of responses evoked by photorelease of GABA in the immature cortical neurons

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    Marat eMinlebaev


    Full Text Available We present a novel non-invasive technique to measure the polarity of GABAergic responses based on cell-attached recordings of currents activated by laser-uncaging of GABA. For these recordings, a patch pipette was filled with a solution containing RuBi-GABA, and GABA was released from this complex by a laser beam conducted to the tip of the patch pipette via an optic fiber. In cell-attached recordings from neocortical and hippocampal neurons in postnatal days P2-5 rat brain slices in vitro, we found that laser-uncaging of GABA activates integral cell-attached currents mediated by tens of GABA(A channels. The initial response was inwardly directed, indicating a depolarizing response to GABA. The direction of the initial response was dependent on the pipette potential and analysis of its slope-voltage relationships revealed a depolarizing driving force of +11 mV for the currents through GABA channels. Initial depolarizing responses to GABA uncaging were inverted to hyperpolarizing in the presence of the NKCC1 blocker bumetanide. Current-voltage relationships of the currents evoked by Rubi-GABA uncaging using voltage-ramps at the peak of responses not only revealed a bumetanide-sensitive depolarizing reversal potential of the GABA(A receptor mediated responses, but also showed a strong voltage-dependent hysteresis. Upon desensitization of the uncaged-GABA response, current-voltage relationships of the currents through single GABA(A channels revealed depolarizing responses with the driving force values similar to those obtained for the initial response. Thus, cell-attached recordings of the responses evoked by local intrapipette GABA uncaging are suitable to assess the polarity of the GABA(A-Rs mediated signals in small cell compartments.

  11. Different subtypes of GABA-A receptors are expressed in human, mouse and rat T lymphocytes.

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    Suresh K Mendu

    Full Text Available γ-Aminobutyric acid (GABA is the most prominent neuroinhibitory transmitter in the brain, where it activates neuronal GABA-A receptors (GABA-A channels located at synapses and outside of synapses. The GABA-A receptors are primary targets of many clinically useful drugs. In recent years, GABA has been shown to act as an immunomodulatory molecule. We have examined in human, mouse and rat CD4(+ and CD8(+ T cells which subunit isoforms of the GABA-A channels are expressed. The channel physiology and drug specificity is dictated by the GABA-A receptor subtype, which in turn is determined by the subunit isoforms that make the channel. There were 5, 8 and 13 different GABA-A subunit isoforms identified in human, mouse and rat CD4(+ and CD8(+ T cells, respectively. Importantly, the γ2 subunit that imposes benzodiazepine sensitivity on the GABA-A receptors, was only detected in the mouse T cells. Immunoblots and immunocytochemistry showed abundant GABA-A channel proteins in the T cells from all three species. GABA-activated whole-cell transient and tonic currents were recorded. The currents were inhibited by picrotoxin, SR95531 and bicuculline, antagonists of GABA-A channels. Clearly, in both humans and rodents T cells, functional GABA-A channels are expressed but the subtypes vary. It is important to bear in mind the interspecies difference when selecting the appropriate animal models to study the physiological role and pharmacological properties of GABA-A channels in CD4(+ and CD8(+ T cells and when selecting drugs aimed at modulating the human T cells function.

  12. GABA increases electrical excitability in a subset of human unmyelinated peripheral axons.

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    Richard W Carr

    Full Text Available BACKGROUND: A proportion of small diameter primary sensory neurones innervating human skin are chemosensitive. They respond in a receptor dependent manner to chemical mediators of inflammation as well as naturally occurring algogens, thermogens and pruritogens. The neurotransmitter GABA is interesting in this respect because in animal models of neuropathic pain GABA pre-synaptically regulates nociceptive input to the spinal cord. However, the effect of GABA on human peripheral unmyelinated axons has not been established. METHODOLOGY/PRINCIPAL FINDINGS: Electrical stimulation was used to assess the effect of GABA on the electrical excitability of unmyelinated axons in isolated fascicles of human sural nerve. GABA (0.1-100 microM increased electrical excitability in a subset (ca. 40% of C-fibres in human sural nerve fascicles suggesting that axonal GABA sensitivity is selectively restricted to a sub-population of human unmyelinated axons. The effects of GABA were mediated by GABA(A receptors, being mimicked by bath application of the GABA(A agonist muscimol (0.1-30 microM while the GABA(B agonist baclofen (10-30 microM was without effect. Increases in excitability produced by GABA (10-30 microM were blocked by the GABA(A antagonists gabazine (10-20 microM, bicuculline (10-20 microM and picrotoxin (10-20 microM. CONCLUSIONS/SIGNIFICANCE: Functional GABA(A receptors are present on a subset of unmyelinated primary afferents in humans and their activation depolarizes these axons, an effect likely due to an elevated intra-axonal chloride concentration. GABA(A receptor modulation may therefore regulate segmental and peripheral components of nociception.

  13. Evidence for a Revised Ion/Substrate Coupling Stoichiometry of GABA Transporters. (United States)

    Willford, Samantha L; Anderson, Cynthia M; Spencer, Shelly R; Eskandari, Sepehr


    Plasma membrane γ-aminobutyric acid (GABA) transporters (GATs) are electrogenic transport proteins that couple the cotranslocation of Na(+), Cl(-), and GABA across the plasma membrane of neurons and glia. A fundamental property of the transporter that determines its ability to concentrate GABA in cells and, hence, regulate synaptic and extra-synaptic GABA concentrations, is the ion/substrate coupling stoichiometry. Here, we scrutinized the currently accepted 2 Na(+):1 Cl(-):1 GABA stoichiometry because it is inconsistent with the measured net charge translocated per co-substrate (Na(+), Cl(-), and GABA). We expressed GAT1 and GAT3 in Xenopus laevis oocytes and utilized thermodynamic and uptake under voltage-clamp measurements to determine the stoichiometry of the GABA transporters. Voltage-clamped GAT1-expressing oocytes were internally loaded with GABA, and the reversal potential (V rev) of the transporter-mediated current was recorded at different external concentrations of Na(+), Cl(-), or GABA. The shifts in V rev for a tenfold change in the external Na(+), Cl(-), and GABA concentration were 84 ± 4, 30 ± 1, and 29 ± 1 mV, respectively. To determine the net charge translocated per Na(+), Cl(-), and GABA, we measured substrate fluxes under voltage clamp in cells expressing GAT1 or GAT3. Charge flux to substrate flux ratios were 0.7 ± 0.1 charge/Na(+), 2.0 ± 0.2 charges/Cl(-), and 2.1 ± 0.1 charges/GABA. Altogether, our results strongly suggest a 3 Na(+):1 Cl(-):1 GABA coupling stoichiometry for the GABA transporters. The revised stoichiometry has important implications for understanding the contribution of GATs to GABAergic signaling in health and disease.

  14. Perturbations in reward-related decision-making induced by reduced prefrontal cortical GABA transmission: Relevance for psychiatric disorders. (United States)

    Piantadosi, Patrick T; Khayambashi, Shahin; Schluter, Magdalen G; Kutarna, Agnes; Floresco, Stan B


    The prefrontal cortex (PFC) is critical for higher-order cognitive functions, including decision-making. In psychiatric conditions such as schizophrenia, prefrontal dysfunction co-occurs with pronounced alterations in decision-making ability. These alterations include a diminished ability to utilize probabilistic reinforcement in guiding future choice, and a reduced willingness to expend effort to receive reward. Among the neurochemical abnormalities observed in the PFC of individuals with schizophrenia are alterations in the production and function of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). To probe how PFC GABA hypofunction may contribute to alterations in cost/benefit decision-making, we assessed the effects GABAA-receptor antagonist bicuculline (BIC; 50 ng in 0.5 μl saline/hemisphere) infusion in the medial PFC of rats during performance on a series of well-validated cost/benefit decision-making tasks. Intra-PFC BIC reduced risky choice and reward sensitivity during probabilistic discounting and decreased the preference for larger rewards associated with a greater effort cost, similar to the behavioral sequelae observed in schizophrenia. Additional experiments revealed that these treatments did not alter instrumental responding on a progressive ratio schedule, nor did they impair the ability to discriminate between reward and no reward. However, BIC induced a subtle but consistent impairment in preference for larger vs. smaller rewards of equal cost. BIC infusion also increased decision latencies and impaired the ability to "stay on task" as indexed by reduced rates of instrumental responding. Collectively, these results implicate prefrontal GABAergic dysfunction as a key contributing factor to abnormal decision-making observed in schizophrenia and other neuropsychiatric conditions with similar neurobiological and behavioral alterations.

  15. Exposure to extremely low frequency electromagnetic fields alters the behaviour, physiology and stress protein levels of desert locusts. (United States)

    Wyszkowska, Joanna; Shepherd, Sebastian; Sharkh, Suleiman; Jackson, Christopher W; Newland, Philip L


    Electromagnetic fields (EMFs) are present throughout the modern world and are derived from many man-made sources including overhead transmission lines. The risks of extremely-low frequency (ELF) electromagnetic fields are particularly poorly understood especially at high field strengths as they are rarely encountered at ground level. Flying insects, however, can approach close to high field strength transmission lines prompting the question as to how these high levels of exposure affect behaviour and physiology. Here we utilise the accessible nervous system of the locust to ask how exposure to high levels of ELF EMF impact at multiple levels. We show that exposure to ELF EMFs above 4 mT leads to reduced walking. Moreover, intracellular recordings from an identified motor neuron, the fast extensor tibiae motor neuron, show increased spike latency and a broadening of its spike in exposed animals. In addition, hind leg kick force, produced by stimulating the extensor tibiae muscle, was reduced following exposure, while stress-protein levels (Hsp70) increased. Together these results suggest that ELF EMF exposure has the capacity to cause dramatic effects from behaviour to physiology and protein expression, and this study lays the foundation to explore the ecological significance of these effects in other flying insects.

  16. Long-term exposure to xenoestrogens alters some brain monoamines and both serum thyroid hormones and cortisol levels in adult male rats

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    Nashwa M. Saied


    Full Text Available The present study was designed to examine the effect of long-term treatment with the phytoestrogen soy isoflavone [(SIF; 43 mg/kg body weight/day] and/or the plastics component bisphenol-A [(BPA; 3 mg/kg body weight/day] on some monoamines in the forebrain and both serum thyroid hormones and cortisol levels of adult rats. Significant increases in serotonin (5-HT and norepinephrine (NE level, and significant decreases in 5-hydroxyindoleacetic acid (5-HIAA level and 5-HIAA/5-HT ratio, were observed after treatment with SIF or BPA. Level of dopamine (DA was increased in SIF-treated group and decreased in BPA-treated group. Activity of monoamine oxidase (MAO was decreased in all treated groups. The level of serum thyroid hormones (fT3 and fT4 was increased after treatment with SIF and decreased after exposure to BPA, while cortisol level was increased in all treated groups. It may be concluded that long-term exposure to SIF or BPA disrupts monoamine levels in the forebrain of adult rats through alteration in the metabolic pathways of amines and disorders of thyroid hormones and cortisol levels.

  17. Perioperative prostate specific antigen levels among coronary artery bypass grafting patients: Does extracorporeal circulation and body temperature induce prostate specific antigen levels alterations? (United States)

    Patris, Emmanuel; Giakoumidakis, Konstantinos; Patris, Vasileios; Kuduvalli, Manoj; Argiriou, Mihalis; Charitos, Christos; Kalaitzis, Christos; Touloupidis, Stavros


    Purpose: The purpose of this study is to compare the perioperative total prostate specific antigen (tPSA) levels among coronary artery bypass grafting (CABG) patients with and without extracorporeal circulation (ECC), to investigate the changes overtime of tPSA in each group separately and to determine the effect of body core temperature on tPSA levels. Materials and Methods: A prospective study was conducted. Our sample was allocated to: (a) Seven patients who underwent off pump CABG (Group I) and (b) 16 CABG patients with ECC (Group II). The levels of tPSA were measured preoperatively (baseline), intra-operatively and at the 4th postoperative day. We compared the two groups on their tPSA levels and we investigated the changes of tPSA overtime in each group separately. Results: Intra-operative serum samples were obtained in significantly lower body temperature in patients of Group II than in those of Group I (31°C vs. 36.9°C, P < 0.001). In each group separately, postoperative tPSA levels were increased significantly compared to the baseline values (2.55 ng/ml vs. 0.39 ng/ml for Group I, P = 0.005 and 4.36 ng/ml vs. 0.77 for Group II, P < 0.001). CABG patients with ECC had significantly lower intra-operative tPSA levels than the baseline values (0.67 ng/ml vs. 0.77 ng/ml, P = 0.008). We did not observe significant differences of tPSA levels between the two groups. Conclusions: CABG surgery affects similarly the perioperative tPSA independently the involvement of ECC. Although all patients had significantly higher early postoperative tPSA levels, only those who underwent CABG with ECC had exceeded normal values and significantly decreased intra-operative tPSA. Hypothermia seems to be the causal factor of tPSA reduction. PMID:25657546

  18. Bisphenol A alters transcript levels of biomarker genes for Major Depressive Disorder in vascular endothelial cells and colon cancer cells. (United States)

    Ribeiro-Varandas, Edna; Pereira, H Sofia; Viegas, Wanda; Delgado, Margarida


    Bisphenol A (BPA) is capable of mimicking endogenous hormones with potential consequences for human health and BPA exposure has been associated with several human diseases including neuropsychiatric disorders. Here, quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) results show that BPA at low concentrations (10 ng/mL and 1 μg/mL) induces differential transcript levels of four biomarker genes for Major Depressive Disorder (MDD) in HT29 human colon adenocarcinona cell line and Human Umbilical Vein Endothelial Cells (HUVEC). These results substantiate increasing concerns of BPA exposure in levels currently detected in humans.

  19. At immature mossy fibers-CA3 connections, activation of presynaptic GABA(B) receptors by endogenously released GABA contributes to synapses silencing. (United States)

    Safiulina, Victoria F; Cherubini, Enrico


    Early in postnatal life correlated GABAergic activity in the hippocampus is thought to play a crucial role in synaptogenesis and in the development of adult neuronal networks. Unlike adulthood, at this developmental stage, mossy fibers (MF) which are the axons of granule cells, release GABA into CA3 principal cells and interneurons. Here, we tested the hypothesis that at MF-CA3 connections, tonic activation of GABA(B) autoreceptors by GABA is responsible for the low probability of release and synapse silencing. Blocking GABA(B) receptors with CGP55845 enhanced the probability of GABA release and switched on silent synapses while the opposite was observed with baclofen. Both these effects were presynaptic and were associated with changes in paired-pulse ratio and coefficient of variation. In addition, enhancing the extracellular GABA concentration by repetitive stimulation of MF or by blocking the GABA transporter GAT-1, switched off active synapses, an effect that was prevented by CGP55845. In the presence of CGP55845, stimulation of MF-induced synaptic potentiation. The shift of E(GABA) from the depolarizing to the hyperpolarizing direction with bumetanide, a blocker of the cation-chloride co-transporter NKCC1, prevented synaptic potentiation and caused synaptic depression, suggesting that the depolarizing action of GABA observed in the presence of CGP55845 is responsible for the potentiating effect. It is proposed that, activation of GABA(B) receptors by spillover of GABA from MF terminals reduces the probability of release and contributes to synapses silencing. This would act as a filter to prevent excessive activation of the auto-associative CA3 network and the emergence of seizures.

  20. General, kappa, delta and mu opioid receptor antagonists mediate feeding elicited by the GABA-B agonist baclofen in the ventral tegmental area and nucleus accumbens shell in rats: reciprocal and regional interactions. (United States)

    Miner, Patricia; Shimonova, Lyudmila; Khaimov, Arthur; Borukhova, Yaffa; Ilyayeva, Ester; Ranaldi, Robert; Bodnar, Richard J


    administration in the VTA or NACs was also preceded by administration of NTX (0.1, 1, 5 μg, 0.5 h), BFNA (0.4, 4 μg, 24 h), NBNI (0.6, 6 μg, 0.5 h) or NTI (0.4, 4 μg, 0.5 h) into the other site with intake measured 1, 2 and 4 h after agonist treatment. VTA NTX significantly reduced NACs baclofen-induced feeding. Correspondingly, NACs NTX significantly reduced VTA baclofen-induced feeding, indicating a robust and bidirectional general opioid and GABA-B receptor feeding interaction. Whereas the high, but not low VTA BFNA dose reduced NACs baclofen-induced feeding, NACs BFNA failed to affect VTA baclofen-induced feeding, indicating a unidirectional mu opioid and GABA-B receptor feeding interaction. Whereas VTA NBNI at both doses reduced NACs baclofen-induced feeding, the high, but not low NACs NBNI dose significantly reduced VTA baclofen-induced feeding, indicating a bidirectional kappa opioid and GABA-B receptor feeding interaction. Whereas VTA NTI only transiently reduced NACs baclofen-induced feeding, NACs NTI failed to affect VTA baclofen-induced feeding, indicating a weak unidirectional delta opioid and GABA-B receptor interaction. Whereas administration of NTX or BFNA into the NACs or VTA marginally reduced spontaneous food intake, NBNI or NTI into the same sites failed to alter food intake alone. Therefore, the present study suggests that GABA employs a distributed brain network in mediating its ingestive effects that is dependent upon intact opioid receptor signaling with kappa opioid receptors more involved than mu and delta opioid receptors underlying these regional effects. An alternative hypothesis to be considered is that these effects could be the sum of two independent drug effects (opioid antagonists decreasing and baclofen increasing food intake).

  1. Histopathological alterations of juvenile green (Acipenser medirostris) and white sturgeon (Acipenser transmontanus) exposed to graded levels of dietary methylmercury. (United States)

    Lee, Jang-Won; Kim, Jae-Won; De Riu, Nicola; Moniello, Giuseppe; Hung, Silas S O


    Triplicate groups of juvenile green and white sturgeon (average weight of 30 ± 2 g) were exposed to one of four concentrations of dietary methylmercury (MeHg; 0, 25, 50, and 100 mg MeHg/kg diet) for 8 weeks to determine and compare the sensitivity of the two sturgeon species from a histopathological perspective. After 4- and 8-week exposure, histological changes were examined in the kidney, liver, gill, skeletal muscle, and heart muscle of both species using light microscopy. Marked abnormalities were observed in the kidney and liver of both sturgeon species after each exposure period; the abnormalities showed progressive histological alterations in severity with increasing doses and duration of exposure. Renal lesions included tubular epithelium degeneration and necrosis, renal corpuscular disintegration, and interstitial tissue degeneration. The changes observed in the livers of both sturgeon species were glycogen depletion and vacuolar degeneration. In the gill and skeletal and heart muscle of green and white sturgeon fed MeHg-added diets, mild histological changes were observed but did not show pronounced difference between the two species. Although the lowest observed effect concentration in both species was the 25 mg MeHg/kg diet, the histological changes in the kidney and liver were more pronounced at all treatments groups of green sturgeon than those of white sturgeon. The current results on structural changes of kidney and liver (i.e., more severe glycogen depletion and tubular epithelium degeneration in green sturgeon) confirmed our previous results, in that green sturgeon exhibited a higher mortality, lower growth rate, and lower protein, lipid, and energy contents in their whole body than white sturgeon under the same MeHg exposures.

  2. Chronic stress induces structural alterations in splenic lymphoid tissue that are associated with changes in corticosterone levels in wistar-kyoto rats. (United States)

    Hernandez, María Eugenia; Martinez-Mota, Lucia; Salinas, Citlaltepetl; Marquez-Velasco, Ricardo; Hernandez-Chan, Nancy G; Morales-Montor, Jorge; Pérez-Tapia, Mayra; Streber, María L; Granados-Camacho, Ivonne; Becerril, Enrique; Javier, Baquera-Heredia; Pavón, Lenin


    Major depressive disorder patients present chronic stress and decreased immunity. The Wistar-Kyoto rat (WKY) is a strain in which the hypothalamic-pituitary-adrenal axis is overactivated. To determine whether chronic stress induces changes in corticosterone levels and splenic lymphoid tissue, 9-week-old male rats were subject to restraint stress (3 h daily), chemical stress (hydrocortisone treatment, 50 mg/Kg weight), mixed stress (restraint plus hydrocortisone), or control treatment (without stress) for 1, 4, and 7 weeks. The serum corticosterone levels by RIA and spleens morphology were analyzed. Corticosterone levels as did the structure, size of the follicles and morphology of the parenchyma (increase in red pulp) in the spleen, varied depending on time and type of stressor. These changes indicate that chronic stress alters the immune response in the spleen in WKY rats by inducing morphological changes, explaining in part the impaired immunity that develops in organisms that are exposed to chronic stress.

  3. Sex Hormones in Allergic Conjunctivitis: Altered Levels of Circulating Androgens and Estrogens in Children and Adolescents with Vernal Keratoconjunctivitis

    Directory of Open Access Journals (Sweden)

    Marta Sacchetti


    Full Text Available Purpose. Vernal keratoconjunctivitis (VKC is a chronic allergic disease mainly affecting boys in prepubertal age and usually recovering after puberty. To evaluate a possible role of sex hormones in VKC, serum levels of sex hormones in children and adolescents with VKC were assessed. Methods. 12 prepubertal and 7 early pubertal boys with active VKC and 6 male patients with VKC in remission phase at late pubertal age and 48 healthy age and sex-matched subjects were included. Serum concentration of estrone, 17 beta-estradiol, dehydroepiandrosterone-sulfate, total testosterone and free testosterone, dihydrotestosterone (DHT, cortisol, delta-4-androstenedione, follicle-stimulating hormone, luteinizing hormone, and sex-hormones binding globuline (SHBG were evaluated. Results. Serum levels of Estrone were significantly increased in all groups of patients with VKC when compared to healthy controls (P<0.001. Prepubertal and early pubertal VKC showed a significant decrease in DHT (P=0.007 and P=0.028, resp. and SHBG (P=0.01 and P=0.002, resp. when compared to controls and serum levels of SHBG were increased in late pubertal VKC in remission phase (P=0.007. Conclusions and Relevance. VKC patients have different circulating sex hormone levels in different phases of the disease and when compared to nonallergic subjects. These findings suggest a role played by sex hormones in the pathogenesis and/or activity of VKC.

  4. Sex Hormones in Allergic Conjunctivitis: Altered Levels of Circulating Androgens and Estrogens in Children and Adolescents with Vernal Keratoconjunctivitis (United States)

    Sacchetti, Marta; Lambiase, Alessandro; Moretti, Costanzo; Bonini, Stefano


    Purpose. Vernal keratoconjunctivitis (VKC) is a chronic allergic disease mainly affecting boys in prepubertal age and usually recovering after puberty. To evaluate a possible role of sex hormones in VKC, serum levels of sex hormones in children and adolescents with VKC were assessed. Methods. 12 prepubertal and 7 early pubertal boys with active VKC and 6 male patients with VKC in remission phase at late pubertal age and 48 healthy age and sex-matched subjects were included. Serum concentration of estrone, 17 beta-estradiol, dehydroepiandrosterone-sulfate, total testosterone and free testosterone, dihydrotestosterone (DHT), cortisol, delta-4-androstenedione, follicle-stimulating hormone, luteinizing hormone, and sex-hormones binding globuline (SHBG) were evaluated. Results. Serum levels of Estrone were significantly increased in all groups of patients with VKC when compared to healthy controls (P < 0.001). Prepubertal and early pubertal VKC showed a significant decrease in DHT (P = 0.007 and P = 0.028, resp.) and SHBG (P = 0.01 and P = 0.002, resp.) when compared to controls and serum levels of SHBG were increased in late pubertal VKC in remission phase (P = 0.007). Conclusions and Relevance. VKC patients have different circulating sex hormone levels in different phases of the disease and when compared to nonallergic subjects. These findings suggest a role played by sex hormones in the pathogenesis and/or activity of VKC. PMID:25756057

  5. Plasma trace elements levels are not altered by submaximal exercise intensities in well-trained endurance euhydrated athletes. (United States)

    González-Haro, Carlos; Soria, Marisol; López-Colón, José L; Llorente, María T; Escanero, Jesús F


    The purpose of this study was to assess the effect of relative exercise intensity on various plasma trace elements in euhydrated endurance athletes. Twenty-seven well-trained endurance athletes performed a cycloergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, workload increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Oxygen uptake, blood lactate concentration ([La⁻](b)), and plasma ions (Zn, Se, Mn and Co) were measured at rest, at the end of each stage, and 3, 5 and 7 min post-exercise. Urine specific gravity (U(SG)) was measured before and after the test, and subjects drank water ad libitum. Fat oxidation (FAT(OXR)), carbohydrate oxidation (CHO(OXR)), energy expenditure from fat (EE(FAT)), from carbohydrates (EE(CHO)) and total EE (EE(T)) were estimated using stoichiometric equations. A repeated measure (ANOVA) was used to compare plasma ion levels at each exercise intensity level. The significance level was set at Pathletes does not provoke a change in plasma trace element levels, suggesting that plasma volume plays an important role in the homeostasis of these elements during exercise.

  6. Potential Association of Lead Exposure During Early Development of Mice With Alteration of Hippocampus Nitric Oxide Levels and Learning Memory

    Institute of Scientific and Technical Information of China (English)



    Objective Chronic lead (Pb) exposure during development is known to produce learning deficits. Nitric oxide participates in the synaptic mechanisms involved in certain forms of learning and memory. This study was designed to clarify whether Pb-induced impairment in learning and memory was associated with the changes of nitric oxide levels in mice brains.Methods Sixty Balb/c mice aged 10 days were chosen. A model of lead exposure was established by drinking 0.025%, 0.05%,0.075% lead acetate, respectively for 8 weeks. The controls were orally given distilled water. The ability to learn and memorize was examined by open field test, T-water maze test. In parallel with the behavioral data, NO level of hippocampus tissue was detected by biochemical assay. Results Compared with control groups, (1) the weight of 0.075% group was significantly reduced (P<0.05); (2) The number of times in mice attaining the required standards in T-water maze test was lower in 0.075%group (P<0.01). No significant difference was found between experimental and control groups in open field test (P>0.05); (3)NO level of mouse hippocampus tissue was decreased in 0.075% group (P<0.01). Conclusions The findings suggest that decreased hippocampus NO level may contribute to the Pb-induced deficits in learning and memory processes.

  7. Altered Circulating Levels of Serotonin and Immunological Changes in Laying Hens Divergently Selected for Feather Pecking Behavior

    DEFF Research Database (Denmark)

    Buitenhuis, Albert Johannes; Kjaer, Jørgen B.; Labouriau, Rodrigo


    The aim of this study was to investigate the changes in immunological parameters as well as changes with respect to plasma levels of serotonin and tryptophan in lines selected for and against feather pecking (FP) behavior [high FP (HP) line and low FP (LP) line] for 5 generations. The hens from...

  8. Gelsolin-Cu/ZnSOD interaction alters intracellular reactive oxygen species levels to promote cancer cell invasion

    KAUST Repository

    Tochhawng, Lalchhandami


    The actin-binding protein, gelsolin, is a well known regulator of cancer cell invasion. However, the mechanisms by which gelsolin promotes invasion are not well established. As reactive oxygen species (ROS) have been shown to promote cancer cell invasion, we investigated on the hypothesis that gelsolin-induced changes in ROS levels may mediate the invasive capacity of colon cancer cells. Herein, we show that increased gelsolin enhances the invasive capacity of colon cancer cells, and this is mediated via gelsolin\\'s effects in elevating intracellular superoxide (O2 .-) levels. We also provide evidence for a novel physical interaction between gelsolin and Cu/ZnSOD, that inhibits the enzymatic activity of Cu/ZnSOD, thereby resulting in a sustained elevation of intracellular O2 .-. Using microarray data of human colorectal cancer tissues from Gene Omnibus, we found that gelsolin gene expression positively correlates with urokinase plasminogen activator (uPA), an important matrix-degrading protease invovled in cancer invasion. Consistent with the in vivo evidence, we show that increased levels of O2 .- induced by gelsolin overexpression triggers the secretion of uPA. We further observed reduction in invasion and intracellular O2 .- levels in colon cancer cells, as a consequence of gelsolin knockdown using two different siRNAs. In these cells, concurrent repression of Cu/ ZnSOD restored intracellular O2 .- levels and rescued invasive capacity. Our study therefore identified gelsolin as a novel regulator of intracellular O2 .- in cancer cells via interacting with Cu/ZnSOD and inhibiting its enzymatic activity. Taken together, these findings provide insight into a novel function of gelsolin in promoting tumor invasion by directly impacting the cellular redox milieu.

  9. Postsynaptic Depolarization Enhances GABA Drive to Dorsomedial Hypothalamic Neurons through Somatodendritic Cholecystokinin Release. (United States)

    Crosby, Karen M; Baimoukhametova, Dinara V; Bains, Jaideep S; Pittman, Quentin J


    Somatodendritically released peptides alter synaptic function through a variety of mechanisms, including autocrine actions that liberate retrograde transmitters. Cholecystokinin (CCK) is a neuropeptide expressed in neurons in the dorsomedial hypothalamic nucleus (DMH), a region implicated in satiety and stress. There are clear demonstrations that exogenous CCK modulates food intake and neuropeptide expression in the DMH, but there is no information on how endogenous CCK alters synaptic properties. Here, we provide the first report of somatodendritic release of CCK in the brain in male Sprague Dawley rats. CCK is released from DMH neurons in response to repeated postsynaptic depolarizations, and acts in an autocrine fashion on CCK2 receptors to enhance postsynaptic NMDA receptor function and liberate the retrograde transmitter, nitric oxide (NO). NO subsequently acts presynaptically to enhance GABA release through a soluble guanylate cyclase-mediated pathway. These data provide the first demonstration of synaptic actions of somatodendritically released CCK in the hypothalamus and reveal a new form of retrograde plasticity, depolarization-induced potentiation of inhibition. Significance statement: Somatodendritic signaling using endocannabinoids or nitric oxide to alter the efficacy of afferent transmission is well established. Despite early convincing evidence for somatodendritic release of neurohypophysial peptides in the hypothalamus, there is only limited evidence for this mode of release for other peptides. Here, we provide the first evidence for somatodendritic release of the satiety peptide cholecystokinin (CCK) in the brain. We also reveal a new form of synaptic plasticity in which postsynaptic depolarization results in enhancement of inhibition through the somatodendritic release of CCK.

  10. Identifying stimuli that alter immediate and subsequent levels of vocal stereotypy: a further analysis of functionally matched stimulation. (United States)

    Lanovaz, Marc J; Fletcher, Sarah E; Rapp, John T


    We used a three-component multiple-schedule with a brief reversal design to evaluate the effects of structurally unmatched and matched stimuli on immediate and subsequent vocal stereotypy that was displayed by three children with autism spectrum disorders. For 2 of the 3 participants, access to matched stimuli, unmatched stimuli, and music decreased immediate levels of vocal stereotypy; however, with the exception of matched stimuli for one participant, none of the stimuli produced a clear abolishing operation for subsequent vocal stereotypy. That is, vocal stereotypy typically increased to baseline levels shortly after alternative stimulation was removed. Detection of motivating operations for each participant's vocal stereotypy was aided by the analysis of component distributions. The results are discussed in terms of immediate and subsequent effects of preferred stimuli on automatically reinforced problem behavior.

  11. Histopathological alterations, biochemical responses and acetylcholinesterase levels in Clarias gariepinus as biomarkers of exposure to organophosphates pesticides. (United States)

    Doherty, V F; Ladipo, M K; Aneyo, I A; Adeola, A; Odulele, W Y


    Organophosphate pesticides, commonly used in large scale farming, have been found to be major contaminants in aquatic environment. Clarias gariepinus was exposed to acute and sublethal concentrations of phostoxin and DD Force to evaluate single and joint action toxicity of the organophosphates. Effects of phostoxin and DD force on antioxidant enzymes, fish organs and acetylcholinesterase levels in fingerlings and juveniles of C. gariepinus were also investigated. The lethal concentrations (96 h LC50) for phostoxin and DD Force were 0.631 and 1.759 mg/l, respectively. The results obtained from the bioassay showed that phostoxin was 2.8× more toxic than DD Force after exposure of C. gariepinus. Joint action toxicity evaluations of phostoxin and DD Force showed that the interaction between the chemicals was synergistic (RTU >1). The biochemical responses in the exposed fish differed significantly (P < 0.05) from the control fish. The result of acetylcholinesterase study revealed significant difference between acetylcholinesterase levels in the exposed fish and control, with reduction in the acetylcholineterase level in fish exposed to sublethal concentrations of phostoxin and DD Force. Haematological studies revealed an increase in WBC, RBC, PCV and platelets in the exposed fish. Histopathology of the gills showed shortened primary lamellae, loss of secondary lamellae and loss of ceratobrachial bones. In the acute toxicity studies, respiratory stress, erratic swimming and instant death of fish were observed in the exposed fish. This study reveals that changes in histopathology and acetylcholinesterase level are good biomarkers and can be successfully used to detect exposure to organophosphates pesticides in fish.

  12. Intracellular GSH Alterations and Its Relationship to Level of Resistance following Exposure to Cisplatin in Cancer Cells


    Jamali, Bardia; Nakhjavani, Maryam; Hosseinzadeh, Leila; Amidi, Salimeh; Nikounezhad, Nastaran; H. Shirazi, Farshad


    One of the major complications in cancer chemotherapy with cisplatin as one of the important medicines in treatment regimens of different cancers is the development of resistance. One of the most described cellular defense mechanisms involved in resistance is glutathione (GSH), thus in this study, the effects of cisplatin on the total intracellular GSH level (GSHi) in some sensitive and resistant variants of human cell lines (hepatocarcinoma HepG2, skin A375, cisplatin sensitive glioblastoma ...

  13. Glutathione peroxidase 1 expression, malondialdehyde levels and histological alterations in the liver of Acrossocheilus fasciatus exposed to cadmium chloride. (United States)

    Liu, Guo-Di; Sheng, Zhang; Wang, You-Fa; Han, Ying-Li; Zhou, Yang; Zhu, Jun-Quan


    Cadmium (Cd) is known as a widespread pollutant in aquatic environment. The accumulation of reactive oxygen species (ROS) is attributed to Cd exposure, which may affect the growth, development and physiological metabolism of aquatic organisms. In response to these unfavorable damages, antioxidant systems have been developed to protect against oxidative stress. In this study, we investigated the expression pattern of glutathione peroxidase 1 genes (GPx-1a and GPx-1b) in the liver of Acrossocheilus fasciatus after Cd administration. Total RNA extraction, reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) were performed in order to clone the A. fasciatus GPx-1a and GPx-1b full-length cDNA sequences and partial fragment of β-actin cDNA from the liver for the first time. Tissue-specific expression analysis proved that GPx-1 genes were widely expressed in the liver, kidney, gill, testis, muscle, spleen, heart and brain. The changes of GPx-1 mRNA and malondialdehyde (MDA) levels in the liver treated with Cd were measured. In addition, the acute toxic effects of Cd on the microstructure of the liver were studied using light microscopy. These results suggest that GPx-1, MDA and liver histology which represent molecular, biochemical and histological levels, can be used as potential biomarkers to monitor Cd pollution. The overall findings also highlight the potential use of those three bio-indicators combined together as a multi-level tool (molecular, biochemical and histological levels) when monitoring Cd contamination and other possible exogenetic pollutants in aquatic environment.

  14. Long-term exposure to paraquat alters behavioral parameters and dopamine levels in adult zebrafish (Danio rerio). (United States)

    Bortolotto, Josiane W; Cognato, Giana P; Christoff, Raissa R; Roesler, Laura N; Leite, Carlos E; Kist, Luiza W; Bogo, Mauricio R; Vianna, Monica R; Bonan, Carla D


    Chronic exposure to paraquat (Pq), a toxic herbicide, can result in Parkinsonian symptoms. This study evaluated the effect of the systemic administration of Pq on locomotion, learning and memory, social interaction, tyrosine hydroxylase (TH) expression, dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels, and dopamine transporter (DAT) gene expression in zebrafish. Adult zebrafish received an i.p. injection of either 10 mg/kg (Pq10) or 20 mg/kg (Pq20) of Pq every 3 days for a total of six injections. Locomotion and distance traveled decreased at 24 h after each injection in both treatment doses. In addition, both Pq10- and Pq20-treated animals exhibited differential effects on the absolute turn angle. Nonmotor behaviors were also evaluated, and no changes were observed in anxiety-related behaviors or social interactions in Pq-treated zebrafish. However, Pq-treated animals demonstrated impaired acquisition and consolidation of spatial memory in the Y-maze task. Interestingly, dopamine levels increased while DOPAC levels decreased in the zebrafish brain after both treatments. However, DAT expression decreased in the Pq10-treated group, and there was no change in the Pq20-treated group. The amount of TH protein showed no significant difference in the treated group. Our study establishes a new model to study Parkinson-associated symptoms in zebrafish that have been chronically treated with Pq.

  15. Altered transcription levels of endocrine associated genes in two fisheries species collected from the Great Barrier Reef catchment and lagoon. (United States)

    Kroon, Frederieke J; Hook, Sharon E; Jones, Dean; Metcalfe, Suzanne; Henderson, Brent; Smith, Rachael; Warne, Michael St J; Turner, Ryan D; McKeown, Adam; Westcott, David A


    The Great Barrier Reef (GBR) is chronically exposed to agricultural run-off containing pesticides, many of which are known endocrine disrupting chemicals (EDCs). Here, we measure mRNA transcript abundance of two EDC biomarkers in wild populations of barramundi (Lates calcarifer) and coral trout (Plectropomus leopardus and Plectropomus maculatus). Transcription levels of liver vitellogenin (vtg) differed significantly in both species amongst sites with different exposures to agricultural run-off; brain aromatase (cyp19a1b) revealed some differences for barramundi only. Exposure to run-off from sugarcane that contains pesticides is a likely pathway given (i) significant associations between barramundi vtg transcription levels, catchment sugarcane land use, and river pesticide concentrations, and (ii) consistency between patterns of coral trout vtg transcription levels and pesticide distribution in the GBR lagoon. Given the potential consequences of such exposure for reproductive fitness and population dynamics, these results are cause for concern for the sustainability of fisheries resources downstream from agricultural land uses.

  16. The pch2Delta mutation in baker's yeast alters meiotic crossover levels and confers a defect in crossover interference.

    Directory of Open Access Journals (Sweden)

    Sarah Zanders


    Full Text Available Pch2 is a widely conserved protein that is required in baker's yeast for the organization of meiotic chromosome axes into specific domains. We provide four lines of evidence suggesting that it regulates the formation and distribution of crossover events required to promote chromosome segregation at Meiosis I. First, pch2Delta mutants display wild-type crossover levels on a small (III chromosome, but increased levels on larger (VII, VIII, XV chromosomes. Second, pch2Delta mutants show defects in crossover interference. Third, crossovers observed in pch2Delta require both Msh4-Msh5 and Mms4-Mus81 functions. Lastly, the pch2Delta mutation decreases spore viability and disrupts crossover interference in spo11 hypomorph strains that have reduced levels of meiosis-induced double-strand breaks. Based on these and previous observations, we propose a model in which Pch2 functions at an early step in crossover control to ensure that every homolog pair receives an obligate crossover.

  17. Intracellular GSH Alterations and Its Relationship to Level of Resistance following Exposure to Cisplatin in Cancer Cells. (United States)

    Jamali, Bardia; Nakhjavani, Maryam; Hosseinzadeh, Leila; Amidi, Salimeh; Nikounezhad, Nastaran; H Shirazi, Farshad


    One of the major complications in cancer chemotherapy with cisplatin as one of the important medicines in treatment regimens of different cancers is the development of resistance. One of the most described cellular defense mechanisms involved in resistance is glutathione (GSH), thus in this study, the effects of cisplatin on the total intracellular GSH level (GSHi) in some sensitive and resistant variants of human cell lines (hepatocarcinoma HepG2, skin A375, cisplatin sensitive glioblastoma U373MG and cisplatin resistant glioblastoma U373MGCP, cisplatin sensitive ovary A2780S and cisplatin resistant A2780CP cells) were studied. MTT assay was performed to measure cytotoxicity of cisplatin (33.3 µM for 1 hour). Following cisplatin exposure, GSHi (per million cells) was evaluated using a photometrical assay up to 90 minutes. Our results indicate that there are significant differences between GSHi content of A2780CP and U373MGCP cells compared to other cell lines. Moreover, IC50 of cisplatin in different cells seems to have a relation with mean of GSH level in 90 minutes (GSH (mean)90). As a conclusion, it seems that resistance to cisplatin in different cell lines is more related with the diverse patterns of GSHi variations following cisplatin exposure than its original level, and/or its cellular increase or decrease. It is also suggested that GSH (mean)90 may be used as a factor for the prediction of cellular resistance to cisplatin.

  18. Synaptically released neurotransmitter fails to desensitize postsynaptic GABA(A) receptors in cerebellar cultures. (United States)

    Mellor, J R; Randall, A D


    GABA concentration jump experiments performed on membrane patches predict that postsynaptic GABA(A) receptors will become desensitized following the release of the contents of a single GABA-containing synaptic vesicle. To examine this we used a single synaptic bouton stimulation technique to directly examine whether postsynaptic GABA(A) receptors in cultured cerebellar granule cells exhibit transmitter-induced desensitization. In a large number of recordings, no evidence was found for desensitization of postsynaptic GABA(A) receptors by vesicularly released transmitter. This was the case even when as many as 40 vesicles were released from a single bouton within 1.5 s. In addition, postsynaptic depolarization and application of the benzodiazepine flunitrazepam, manipulations previously shown to enhance desensitization of GABA(A) receptors, failed to unmask transmitter-induced desensitization. In contrast, a single 2- to 3-s application of a high concentration of exogenous GABA was able to depress synaptic responsiveness for up to 70 s. Furthermore, pharmacological depletion of GABA eliminated inhibitory synaptic communication, suggesting that GABA is the transmitter and the desensitization-resistant inhibitory postsynaptic currents are not mediated by a "nondesensitizing" ligand such as beta-alanine. Overall our data indicate that a specific desensitization-resistant population of GABA(A) receptors are present at postsynaptic sites on cultured cerebellar granule cells.

  19. Dioxin exposure reduces the steroidogenic capacity of mouse antral follicles mainly at the level of HSD17B1 without altering atresia. (United States)

    Karman, Bethany N; Basavarajappa, Mallikarjuna S; Hannon, Patrick; Flaws, Jodi A


    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent ovarian toxicant. Previously, we demonstrated that in vitro TCDD (1nM) exposure decreases production/secretion of the sex steroid hormones progesterone (P4), androstenedione (A4), testosterone (T), and 17β-estradiol (E2) in mouse antral follicles. The purpose of this study was to determine the mechanism by which TCDD inhibits steroidogenesis. Specifically, we examined the effects of TCDD on the steroidogenic enzymes, atresia, and the aryl hydrocarbon receptor (AHR) protein. TCDD exposure for 48h increased levels of A4, without changing HSD3B1 protein, HSD17B1 protein, estrone (E1), T or E2 levels. Further, TCDD did not alter atresia ratings compared to vehicle at 48h. TCDD, however, did down regulate the AHR protein at 48h. TCDD exposure for 96h decreased transcript levels for Cyp11a1, Cyp17a1, Hsd17b1, and Cyp19a1, but increased Hsd3b1 transcript. TCDD exposure particularly lowered both Hsd17b1 transcript and HSD17B1 protein. However, TCDD exposure did not affect levels of E1 in the media nor atresia ratings at 96h. TCDD, however, decreased levels of the proapoptotic factor Bax. Collectively, these data suggest that TCDD exposure causes a major block in the steroidogenic enzyme conversion of A4 to T and E1 to E2 and that it regulates apoptotic pathways, favoring survival over death in antral follicles. Finally, the down-regulation of the AHR protein in TCDD exposed follicles persisted at 96h, indicating that the activation and proteasomal degradation of this receptor likely plays a central role in the impaired steroidogenic capacity and altered apoptotic pathway of exposed antral follicles.

  20. Investigating the Role of Glutamate and GABA in the Modulation of Transthalamic Activity: A Combined fMRI-fMRS Study (United States)

    Just, Nathalie; Sonnay, Sarah


    The Excitatory-Inhibitory balance (EIB) between glutamatergic and GABAergic neurons is known to regulate the function of thalamocortical neurocircuits. The thalamus is known as an important relay for glutamatergic and GABAergic signals ascending/descending to/from the somatosensory cortex in rodents. However, new investigations attribute a larger role to thalamic nuclei as modulators of information processing within the cortex. In this study, functional Magnetic Resonance Spectroscopy (fMRS) was used to measure glutamate (Glu) and GABA associations with BOLD responses during activation of the thalamus to barrel cortex (S1BF) pathway at 9.4T. In line with previous studies in humans, resting GABA and Glu correlated negatively and positively respectively with BOLD responses in S1BF. Moreover, a significant negative correlation (R = −0.68, p = 0.0024) between BOLD responses in the thalamus and the barrel cortex was found. Rats with low Glu levels and high resting GABA levels in S1BF demonstrated lower BOLD responses in S1BF and high amplitude BOLD responses in the thalamus themselves linked to the release of high GABA levels during stimulation. In addition, early analysis of resting state functional connectivity suggested EIB controlled thalamocortical neuronal synchrony. We propose that the presented approach may be useful for further characterization of diseases affecting thalamocortical neurotransmission. PMID:28197105

  1. Glutamate and GABA concentration changes in the globus pallidus internus of Parkinson's patients during performance of implicit and declarative memory tasks: a report of two subjects. (United States)

    Buchanan, Robert J; Gjini, Klevest; Darrow, David; Varga, Georgeta; Robinson, Jennifer L; Nadasdy, Zoltan


    The basal ganglia, typically associated with motor function, are involved in human cognitive processes, as demonstrated in behavioral, lesion, and noninvasive functional neuroimaging studies. Here we report task-contingent changes in concentrations of the neurotransmitters glutamate (Glu) and gamma-aminobutyric acid (GABA) in the globus pallidus internus (GPi) of two patients with Parkinson's disease undergoing deep brain stimulation surgery by utilizing in-vivo microdialysis measurements during performance of implicit and declarative memory tasks. Performance of an implicit memory task (weather prediction task-WPT) was associated with increased levels of glutamate and GABA in the GPi compared to their concentrations at baseline. On the other hand, performance of a declarative memory task (verbal learning task-VLT) was associated with decreased levels of glutamate and GABA in GPi compared to baseline during the encoding and immediate recall phase with less conclusive results during the delayed recall phase. These results are in line with hypothesized changes in these neurotransmitter levels: an increase of excitatory (Glu) input from subthalamic nucleus (STN) to GPi during implicit memory task performance and a decrease of inhibitory inputs (GABA) from globus pallidus externus (GPe) and striatum to GPi during declarative memory performance. Consistent with our previous report on in-vivo neurotransmitter changes during tasks in STN, these data provide corroborative evidence for the direct involvement of basal ganglia in cognitive functions and complements our model of the functional circuitry of basal ganglia in the healthy and Parkinson's disease affected brain.

  2. The alterations in adenosine nucleotides and lactic acid levels in striated muscles following death with cervical dislocation or electric shock. (United States)

    Pençe, Halime Hanim; Pençe, Sadrettin; Kurtul, Naciye; Bakan, Ebubekir; Kök, Ahmet Nezih; Kocoglu, Hasan


    In this study, changes in adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and lactic acid levels in masseter, triceps, and quadriceps muscles obtained from right and left sides of Spraque-Dawley rats following two different types of death were investigated. The samples were taken immediately and 120 minutes after death occurred either by cervical dislocation or electric shock. ATP concentrations in the muscles of masseter, triceps, and quadriceps were lower in samples obtained 120 minutes after death than that of samples obtained immediately after death. ADP, AMP, and lactic acid concentrations in these muscles were higher in samples obtained 120 minutes after death than those obtained immediately after death. A positive linear correlation was determined between ATP and ADP concentrations in quadriceps muscles of the rats killed with cervical dislocation and in masseter muscles of the rats killed with electric shock. When the rats killed with cervical dislocation and with electric shock were compared, ADP, AMP, and lactic acid concentrations were lower in the former than in the latter for both times (immediately and 120 minutes after death occurred). In the case of electric shock, ATP is consumed faster because of immediate contractions during death, resulting in a faster rigor mortis. This finding was confirmed with higher lactic acid levels in muscles of the rats killed with electric shock than the other group. In the cervical dislocation and electric shock group rats, ATP decreased in different levels in the three different muscle types mentioned above, being much decline in masseter in cervical dislocation and in quadriceps in electric shock group. This may be caused by low mass and less glycogen storage of masseter and by near localisation of electrode to quadriceps. One can conclude that the occurrence of rigor mortis is closely related to the mode of death.

  3. Alterations in glutathione levels and apoptotic regulators are associated with acquisition of arsenic trioxide resistance in multiple myeloma.

    Directory of Open Access Journals (Sweden)

    Shannon M Matulis

    Full Text Available Arsenic trioxide (ATO has been tested in relapsed/refractory multiple myeloma with limited success. In order to better understand drug mechanism and resistance pathways in myeloma we generated an ATO-resistant cell line, 8226/S-ATOR05, with an IC50 that is 2-3-fold higher than control cell lines and significantly higher than clinically achievable concentrations. Interestingly we found two parallel pathways governing resistance to ATO in 8226/S-ATOR05, and the relevance of these pathways appears to be linked to the concentration of ATO used. We found changes in the expression of Bcl-2 family proteins Bfl-1 and Noxa as well as an increase in cellular glutathione (GSH levels. At low, clinically achievable concentrations, resistance was primarily associated with an increase in expression of the anti-apoptotic protein Bfl-1 and a decrease in expression of the pro-apoptotic protein Noxa. However, as the concentration of ATO increased, elevated levels of intracellular GSH in 8226/S-ATOR05 became the primary mechanism of ATO resistance. Removal of arsenic selection resulted in a loss of the resistance phenotype, with cells becoming sensitive to high concentrations of ATO within 7 days following drug removal, indicating changes associated with high level resistance (elevated GSH are dependent upon the presence of arsenic. Conversely, not until 50 days without arsenic did cells once again become sensitive to clinically relevant doses of ATO, coinciding with a decrease in the expression of Bfl-1. In addition we found cross-resistance to melphalan and doxorubicin in 8226/S-ATOR05, suggesting ATO-resistance pathways may also be involved in resistance to other chemotherapeutic agents used in the treatment of multiple myeloma.

  4. Enhanced polyamine accumulation alters carotenoid metabolism at the transcriptional level in tomato fruit over-expressing spermidine synthase. (United States)

    Neily, Mohamed Hichem; Matsukura, Chiaki; Maucourt, Mickaël; Bernillon, Stéphane; Deborde, Catherine; Moing, Annick; Yin, Yong-Gen; Saito, Takeshi; Mori, Kentaro; Asamizu, Erika; Rolin, Dominique; Moriguchi, Takaya; Ezura, Hiroshi


    Polyamines are involved in crucial plant physiological events, but their roles in fruit development remain unclear. We generated transgenic tomato plants that show a 1.5- to 2-fold increase in polyamine content by over-expressing the spermidine synthase gene, which encodes a key enzyme for polyamine biosynthesis. Pericarp-columella and placental tissue from transgenic tomato fruits were subjected to (1)H-nuclear magnetic resonance (NMR) for untargeted metabolic profiling and high-performance liquid chromatography-diode array detection for carotenoid profiling to determine the effects of high levels of polyamine accumulation on tomato fruit metabolism. A principal component analysis of the quantitative (1)H NMR data from immature green to red ripe fruit showed a clear discrimination between developmental stages, especially during ripening. Quantification of 37 metabolites in pericarp-columella and 41 metabolites in placenta tissues revealed distinct metabolic profiles between the wild type and transgenic lines, particularly at the late ripening stages. Notably, the transgenic tomato fruits also showed an increase in carotenoid accumulation, especially in lycopene (1.3- to 2.2-fold), and increased ethylene production (1.2- to 1.6-fold) compared to wild-type fruits. Genes responsible for lycopene biosynthesis, including phytoene synthase, phytoene desaturase, and deoxy-d-xylulose 5-phosphate synthase, were significantly up-regulated in ripe transgenic fruits, whereas genes involved in lycopene degradation, including lycopene-epsilon cyclase and lycopene beta cyclase, were down-regulated in the transgenic fruits compared to the wild type. These results suggest that a high level of accumulation of polyamines in the tomato regulates the steady-state level of transcription of genes responsible for the lycopene metabolic pathway, which results in a higher accumulation of lycopene in the fruit.

  5. Methoxychlor-induced alteration in the levels of HSP70 and clusterin is accompanied with oxidative stress in adult rat testis. (United States)

    Vaithinathan, S; Saradha, B; Mathur, P P


    Methoxychlor, an organochlorine pesticide, has been reported to induce abnormalities in male reproductive tract. However, the insight into the mechanisms of gonadal toxicity induced by methoxychlor is not well known. We investigated whether treatment with methoxychlor would alter the levels of stress proteins, heat shock proteins (HSP), and clusterin (CLU), and oxidative stress-related parameters in the testis of adult male rats. Animals were exposed to a single dose of methoxychlor (50 mg/kg body weight) orally and were terminated at various time points (0, 3, 6, 12, 24, and 72 h) using anesthetic ether. The levels of HSP70, CLU, and the activities of superoxide dismutase (SOD), catalase, and lipid peroxidation levels were evaluated in a 10% testis homogenate. A sequential reduction in the activities of catalase and SOD with concomitant increase in the levels of thiobarbituric acid reactive substance (TBARS) was observed. These changes elicited by methoxychlor were very significant between 6-12 h of posttreatment. Immunoblot analysis of HSP revealed the expression of HSP72, an inducible form of HSP, at certain time points (3-24 h) following exposure to methoxychlor. Similarly, the levels of secretory CLU (sCLU) were also found to be elevated between 3-24 h of treatment. The present data demonstrate methoxychlor-elicited increase in the levels of inducible HSP72 and sCLU, which could be a part of protective mechanism mounted to reduce cellular oxidative damage.

  6. Pharmacological analysis of the activation and receptor properties of the tonic GABA(CR current in retinal bipolar cell terminals.

    Directory of Open Access Journals (Sweden)

    Stefanie M Jones

    Full Text Available GABAergic inhibition in the central nervous system (CNS can occur via rapid, transient postsynaptic currents and via a tonic increase in membrane conductance, mediated by synaptic and extrasynaptic GABA(A receptors (GABA(ARs respectively. Retinal bipolar cells (BCs exhibit a tonic current mediated by GABA(CRs in their axon terminal, in addition to synaptic GABA(AR and GABA(CR currents, which strongly regulate BC output. The tonic GABA(CR current in BC terminals (BCTs is not dependent on vesicular GABA release, but properties such as the alternative source of GABA and the identity of the GABA(CRs remain unknown. Following a recent report that tonic GABA release from cerebellar glial cells is mediated by Bestrophin 1 anion channels, we have investigated their role in non-vesicular GABA release in the retina. Using patch-clamp recordings from BCTs in goldfish retinal slices, we find that the tonic GABA(CR current is not reduced by the anion channel inhibitors NPPB or flufenamic acid but is reduced by DIDS, which decreases the tonic current without directly affecting GABA(CRs. All three drugs also exhibit non-specific effects including inhibition of GABA transporters. GABA(CR ρ subunits can form homomeric and heteromeric receptors that differ in their properties, but BC GABA(CRs are thought to be ρ1-ρ2 heteromers. To investigate whether GABA(CRs mediating tonic and synaptic currents may differ in their subunit composition, as is the case for GABA(ARs, we have examined the effects of two antagonists that show partial ρ subunit selectivity: picrotoxin and cyclothiazide. Tonic and synaptic GABA(CR currents were differentially affected by both drugs, suggesting that a population of homomeric ρ1 receptors contributes to the tonic current. These results extend our understanding of the multiple forms of GABAergic inhibition that exist in the CNS and contribute to visual signal processing in the retina.

  7. GABA transporter 1 transcriptional starting site exhibiting tissue specific difference

    Institute of Scientific and Technical Information of China (English)


    GABA transporter 1(GAT1)takes important roles in multiple physiological processes through the uptake and release of GABA,but the regulation of GAT1 gene expression in different tissues is rarely known.To address the question,first,5' Rapid amplification of cDNA end(RACE)was used to determine GAT1 transcriptional starting sites in neonatal mouse cerebral cortex and intestine,adult mouse brain and adult rat testis.The products of 5'RACE were confirmed by DNA sequencing.We found that the transcript of GAT1 in neonatal mouse cerebral cortex and adult mouse brain starts at the same site(inside of exon 1),while in mouse intestine,GAT1 starts transcription in intron 1,and in rat testis,the transcript of GAT1 has an additional untranslation exon to the 5' direction.

  8. Striatal cholinergic interneurons Drive GABA release from dopamine terminals. (United States)

    Nelson, Alexandra B; Hammack, Nora; Yang, Cindy F; Shah, Nirao M; Seal, Rebecca P; Kreitzer, Anatol C


    Striatal cholinergic interneurons are implicated in motor control, associative plasticity, and reward-dependent learning. Synchronous activation of cholinergic interneurons triggers large inhibitory synaptic currents in dorsal striatal projection neurons, providing one potential substrate for control of striatal output, but the mechanism for these GABAergic currents is not fully understood. Using optogenetics and whole-cell recordings in brain slices, we find that a large component of these inhibitory responses derive from action-potential-independent disynaptic neurotransmission mediated by nicotinic receptors. Cholinergically driven IPSCs were not affected by ablation of striatal fast-spiking interneurons but were greatly reduced after acute treatment with vesicular monoamine transport inhibitors or selective destruction of dopamine terminals with 6-hydroxydopamine, indicating that GABA release originated from dopamine terminals. These results delineate a mechanism in which striatal cholinergic interneurons can co-opt dopamine terminals to drive GABA release and rapidly inhibit striatal output neurons.

  9. Bacillus sp. QSI-1 Modulate Quorum Sensing Signals Reduce Aeromonas hydrophila Level and Alter Gut Microbial Community Structure in Fish (United States)

    Zhou, Shuxin; Zhang, An; Yin, Hongping; Chu, Weihua


    Quorum sensing (QS) is a cell density dependent process that enables bacteria to communicate with each other based on the production, secretion and sensing of the auto-inducer molecules and then subsequently regulate virulence associated gene expression. Interrupting quorum sensing may represent a novel alternative approach to combat bacterial pathogen. Several bacteria can produce quorum quenching (QQ) enzymes. However, the role of QQ bacteria in shaping the microbiota and the level of N-acyl-homoserine lactones (AHLs, a prevalent type of QS molecules) producing bacteria remains largely unknown. The objective of this study was to examine the presence of AHLs in the fish intestine and investigate the modulation of gut microbiota and its effect on Aeromonas hydrophila level by a QQ enzyme producing probiotic Bacillus sp. QSI-1. AHLs were found in fish gut content and were confirmed in Aeromonas species using Chromobacterium violaceum CV026 and Agrobacterium tumefaciens AT 136 (pZLR4) as reporter strains. We demonstrated that the composition of fish gut microbiota was affected by quenching bacteria QSI-1, and the percentage of A. hydrophila was decreased significantly. Taken together, these results provide valuable insights into QQ enzyme producing probiotics can modulate the microbiota structure and decrease the percentage of AHL-producing pathogenic bacteria in the gut. These data strongly suggest that QQ probiotics may serve as non-antibiotic feed additive in aquaculture to control bacterial diseases. PMID:28018866

  10. Comparative study of antibody levels developed by vaccination against polio virus in population after vaccine type alteration. (United States)

    Farkas, Ágnes; Magyar, Nóra; Szomor, Katalin N; Takács, Mária


    During clinical trials, samples from Hungarian patients of different age groups were tested for antibodies against all 3 serotypes of poliovirus, a member of Picornaviridae family. During the virus neutralization serological test, blood samples were titrated using permanent virus concentration. Based on the cythopathic effect observed under a light microscope, the antibody level of the patient was assessed. The 100 people examined were classified into 5 groups based on age and type of original vaccine: I. Newborns, no vaccination given; II. Immunosuppressed patients; III. Born before 1986, received only OPV vaccine; IV. Born between 1992-2005, received a combination of OPV and IPV vaccines; V. Born after 2006, received only IPV vaccine. Results show that vaccination coverage meets all the criteria. None of the immunized persons was seronegative to all three polioviruses. Both IPV and OPV vaccines are effective against poliovirus. Blood samples from newborn babies with no immunization were also examined. Results show that most newborns have maternal antibodies in their blood. Results of group II show that immunosuppression does not have a negative influence on blood antibody levels against polioviruses. In spite of the low number of samples, our results show that seroconversion after immunization in the Hungarian population is adequate. For more accurate results about vaccination coverage in the population, further trials would be necessary.

  11. Alteration of Porcine Serum Albumin Levels in Pork Meat by Marination in Kiwi or Pineapple Juice and Subsequent Pan Broiling. (United States)

    Moon, Sung-Sil; Kim, Dongwook; Kim, Il-Suk; Ham, Jun-Sang; Park, Beom-Young; Jang, Aera


    This study was conducted to evaluate the changes in porcine serum albumin (PSA), a major allergen, which occur when raw pork ham is marinated with kiwi or pineapple juice, and/or when the ham is pan broiled at 300℃ for 4 min after marination. In this study, raw pork ham was soaked for 4 h or 8 h in marinades containing commercial marinating sauce only, commercial marinating sauce and 7% kiwi juice, or commercial marinating sauce and 7% pineapple juice. When the meat was marinated and then pan-broiled, pork ham meat protein was significantly denatured and hydrolyzed, and the level of PSA in the meat was significantly reduced. The PSA contents of pork broiled without marination, pork that had been marinated in commercial marinating sauce alone, pork that had been marinated in commercial marinating sauce with kiwi juice, and pork that had been marinated in commercial marinating sauce with pineapple juice, were 95.4, 43.3, 14.3, and 5.4 ng/mL, respectively (pkiwi juice; and marination for 8 h was more effective than marinating for 4 h. These results indicate that the level of PSA in pork ham is effectively reduced, when the meat is first marinated in sauces that contain kiwi or pineapple extracts for 8 h, rather than 4 h, and then cooked. Further study is needed to determine whether marinated pork meat reduces allergenicity in vivo, as well.

  12. Sarcopenia, obesity, and natural killer cell immune senescence in aging: altered cytokine levels as a common mechanism. (United States)

    Lutz, Charles T; Quinn, LeBris S


    Human aging is characterized by both physical and physiological frailty. A key feature of frailty, sarcopenia is the age-associated decline in skeletal muscle mass, strength, and endurance that characterize even the healthy elderly. Increases in adiposity, particularly in visceral adipose tissue, are almost universal in aging individuals and can contribute to sarcopenia and insulin resistance by increasing levels of inflammatory cytokines known collectively as adipokines. Aging also is associated with declines in adaptive and innate immunity, known as immune senescence, which are risk factors for cancer and all-cause mortality. The cytokine interleukin-15 (IL-15) is highly expressed in skeletal muscle tissue and declines in aging rodent models. IL-15 inhibits fat deposition and insulin resistance, is anabolic for skeletal muscle in certain situations, and is required for the development and survival of natural killer (NK) lymphocytes. We review the effect that adipokines and myokines have on NK cells, with special emphasis on IL-15. We posit that increased adipokine and decreased IL-15 levels during aging constitute a common mechanism for sarcopenia, obesity, and immune senescence.

  13. CypD(-/-) hearts have altered levels of proteins involved in Krebs cycle, branch chain amino acid degradation and pyruvate metabolism. (United States)

    Menazza, Sara; Wong, Renee; Nguyen, Tiffany; Wang, Guanghui; Gucek, Marjan; Murphy, Elizabeth


    Cyclophilin D (CypD) is a mitochondrial chaperone that has been shown to regulate the mitochondrial permeability transition pore (MPTP). MPTP opening is a major determinant of mitochondrial dysfunction and cardiomyocyte death during ischemia/reperfusion (I/R) injury. Mice lacking CypD have been widely used to study regulation of the MPTP, and it has been shown recently that genetic depletion of CypD correlates with elevated levels of mitochondrial Ca(2+). The present study aimed to characterize the metabolic changes in CypD(-/-) hearts. Initially, we used a proteomics approach to examine protein changes in CypD(-/-) mice. Using pathway analysis, we found that CypD(-/-) hearts have alterations in branched chain amino acid metabolism, pyruvate metabolism and the Krebs cycle. We tested whether these metabolic changes were due to inhibition of electron transfer from these metabolic pathways into the electron transport chain. As we found decreased levels of succinate dehydrogenase and electron transfer flavoprotein in the proteomics analysis, we examined whether activities of these enzymes might be altered. However, we found no alterations in their activities. The proteomics study also showed a 23% decrease in carnitine-palmitoyltransferase 1 (CPT1), which prompted us to perform a metabolomics analysis. Consistent with the decrease in CPT1, we found a significant decrease in C4/Ci4, C5-OH/C3-DC, C12:1, C14:1, C16:1, and C20:3 acyl carnitines in hearts from CypD(-/-) mice. In summary, CypD(-/-) hearts exhibit changes in many metabolic pathways and caution should be used when interpreting results from these mice as due solely to inhibition of the MPTP.

  14. Protective effect of montelukast against quinolinic acid/malonic acid induced neurotoxicity: possible behavioral, biochemical, mitochondrial and tumor necrosis factor-α level alterations in rats. (United States)

    Kalonia, H; Kumar, P; Kumar, A; Nehru, B


    The present study has been designed to explore the protective effect of montelukast (leukotriene receptor antagonist) against intrastriatal quinolinic acid (QA; 300 nmol) and malonic acid (MA; 6 μmol) induced Huntington's like symptoms in rats. Quinolinic acid has been reported to induce excitotoxicity by stimulating the N-methyl-D-aspartate receptor, causing calcium overload which in turn leads to the neurodegeneration. On the other hand, MA, being a reversible inhibitor of mitochondrial enzyme complex-II, leads to energy crisis and free radical generation. Recent studies have reported the therapeutic potential of leukotriene receptor antagonists in different neurodegenerative disorders. However, their exact role is yet to be established. The present study accordingly, is an attempt to investigate the effect of montelukast against QA and MA induced behavioral, biochemical and molecular alterations in rat striatum. Oxidative stress, mitochondrial enzyme complex and tumor necrosis factor-alpha (TNF-α) were evaluated on day 21st and 14th post intrastriatal QA and MA treatment, respectively. Findings of the present study demonstrate significant alteration in the locomotor activity and motor coordination as well as oxidative burden (increased lipid peroxidation, nitrite concentration and decreased endogenous antioxidants), mitochondrial enzyme complex (I, II and IV) activities and TNF-α level, in both intrastriatal QA and MA treated animals. Further, montelukast (0.4, 0.8 mg/kg p.o.) treatment for 21 and 14 days respectively, attenuated the behavioral alterations, oxidative stress, mitochondrial dysfunction and TNF-α level in these models of Huntington's disease in a significant manner. In conclusion, the present study emphasizes the neuroprotective potential of montelukast in the therapeutic management of Huntington like symptoms.

  15. A possible role of the non-GAT1 GABA transporters in transfer of GABA from GABAergic to glutamatergic neurons in mouse cerebellar neuronal cultures

    DEFF Research Database (Denmark)

    Suñol, C; Babot, Z; Cristòfol, R


    . The distribution of GAD, GABA and the vesicular glutamate transporter VGlut-1 was assessed using specific antibodies combined with immunofluorescence microscopy. Additionally, tiagabine, SKF 89976-A, betaine, beta-alanine, nipecotic acid and guvacine were used to inhibit the GAT1, betaine/GABA (BGT1), GAT2 and GAT...... neurons constituting the majority of the cells. GABA uptake exhibited the kinetics of high affinity transport and could be partly (20%) inhibited by betaine (IC(50) 142 microM), beta-alanine (30%) and almost fully (90%) inhibited by SKF 89976-A (IC(50) 0.8 microM) or nipecotic acid and guvacine at 1 m...... no effect on the overall GABA content. The inhibitory action of beta-alanine and high concentrations of nipecotic acid and guvacine on GABA transport strongly suggests that also GAT2 or GAT3 (HUGO nomenclature) could play a role....

  16. Adaptation in sound localization: from GABA(B) receptor-mediated synaptic modulation to perception. (United States)

    Stange, Annette; Myoga, Michael H; Lingner, Andrea; Ford, Marc C; Alexandrova, Olga; Felmy, Felix; Pecka, Michael; Siveke, Ida; Grothe, Benedikt


    Across all sensory modalities, the effect of context-dependent neural adaptation can be observed at every level, from receptors to perception. Nonetheless, it has long been assumed that the processing of interaural time differences, which is the primary cue for sound localization, is nonadaptive, as its outputs are mapped directly onto a hard-wired representation of space. Here we present evidence derived from in vitro and in vivo experiments in gerbils indicating that the coincidence-detector neurons in the medial superior olive modulate their sensitivity to interaural time differences through a rapid, GABA(B) receptor-mediated feedback mechanism. We show that this mechanism provides a gain control in the form of output normalization, which influences the neuronal population code of auditory space. Furthermore, psychophysical tests showed that the paradigm used to evoke neuronal GABA(B) receptor-mediated adaptation causes the perceptual shift in sound localization in humans that was expected on the basis of our physiological results in gerbils.

  17. Ionotropic GABA and Glutamate Receptor Mutations and Human Neurologic Diseases. (United States)

    Yuan, Hongjie; Low, Chian-Ming; Moody, Olivia A; Jenkins, Andrew; Traynelis, Stephen F


    The advent of whole exome/genome sequencing and the technology-driven reduction in the cost of next-generation sequencing as well as the introduction of diagnostic-targeted sequencing chips have resulted in an unprecedented volume of data directly linking patient genomic variability to disorders of the brain. This information has the potential to transform our understanding of neurologic disorders by improving diagnoses, illuminating the molecular heterogeneity underlying diseases, and identifying new targets for therapeutic treatment. There is a strong history of mutations in GABA receptor genes being involved in neurologic diseases, particularly the epilepsies. In addition, a substantial number of variants and mutations have been found in GABA receptor genes in patients with autism, schizophrenia, and addiction, suggesting potential links between the GABA receptors and these conditions. A new and unexpected outcome from sequencing efforts has been the surprising number of mutations found in glutamate receptor subunits, with the GRIN2A gene encoding the GluN2A N-methyl-d-aspartate receptor subunit being most often affected. These mutations are associated with multiple neurologic conditions, for which seizure disorders comprise the largest group. The GluN2A subunit appears to be a locus for epilepsy, which holds important therapeutic implications. Virtually all α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor mutations, most of which occur within GRIA3, are from patients with intellectual disabilities, suggesting a link to this condition. Similarly, the most common phenotype for kainate receptor variants is intellectual disability. Herein, we summarize the current understanding of disease-associated mutations in ionotropic GABA and glutamate receptor families, and discuss implications regarding the identification of human mutations and treatment of neurologic diseases.

  18. Altered levels of the Taraxacum kok-saghyz (Russian dandelion) small rubber particle protein, TkSRPP3, result in qualitative and quantitative changes in rubber metabolism. (United States)

    Collins-Silva, Jillian; Nural, Aise Taban; Skaggs, Amanda; Scott, Deborah; Hathwaik, Upul; Woolsey, Rebekah; Schegg, Kathleen; McMahan, Colleen; Whalen, Maureen; Cornish, Katrina; Shintani, David


    Several proteins have been identified and implicated in natural rubber biosynthesis, one of which, the small rubber particle protein (SRPP), was originally identified in Hevea brasiliensis as an abundant protein associated with cytosolic vesicles known as rubber particles. While previous in vitro studies suggest that SRPP plays a role in rubber biosynthesis, in vivo evidence is lacking to support this hypothesis. To address this issue, a transgene approach was taken in Taraxacum kok-saghyz (Russian dandelion or Tk) to determine if altered SRPP levels would influence rubber biosynthesis. Three dandelion SRPPs were found to be highly abundant on dandelion rubber particles. The most abundant particle associated SRPP, TkSRPP3, showed temporal and spatial patterns of expression consistent with patterns of natural rubber accumulation in dandelion. To confirm its role in rubber biosynthesis, TkSRPP3 expression was altered in Russian dandelion using over-expression and RNAi methods. While TkSRPP3 over-expressing lines had slightly higher levels of rubber in their roots, relative to the control, TkSRPP3 RNAi lines showed significant decreases in root rubber content and produced dramatically lower molecular weight rubber than the control line. Not only do results here provide in vivo evidence of TkSRPP proteins affecting the amount of rubber in dandelion root, but they also suggest a function in regulating the molecular weight of the cis-1, 4-polyisoprene polymer.

  19. L-carnitine Mediated Reduction in Oxidative Stress and Alteration in Transcript Level of Antioxidant Enzymes in Sheep Embryos Produced In Vitro. (United States)

    Mishra, A; Reddy, I J; Gupta, P S P; Mondal, S


    The objective of this study was to find out the effect of L-carnitine on oocyte maturation and subsequent embryo development, with L-carnitine-mediated alteration if any in transcript level of antioxidant enzymes (GPx, Cu/Zn-SOD (SOD1) and Mn-SOD (SOD2) in oocytes and developing sheep embryos produced in vitro. Different concentrations of L-carnitine (0 mm, 2.5 mm, 5 mm, 7.5 mm and 10 mm) were used in maturation medium. Oocytes matured with 10 mm L-carnitine showed significantly (p carnitine were not significantly different. Maturation rate was not influenced by supplementation of any experimental concentration of L-carnitine. There was a significant (p carnitine-treated oocytes and embryos than control group. Antioxidant effect of L-carnitine was proved by culturing oocytes and embryos with H2O2 in the presence of L-carnitine which could be able to protect oocytes and embryos from H2O2-induced oxidative damage. L-carnitine supplementation significantly (p carnitine supplementation during in vitro maturation reduces oxidative stress-induced embryo toxicity by decreasing intracellular ROS and increasing intracellular GSH that in turn improved developmental potential of oocytes and embryos and alters transcript level of antioxidant enzymes.

  20. Plasma glucagon-like peptide 1 and peptide YY levels are not altered in symptomatic fructose-sorbitol malabsorption

    DEFF Research Database (Denmark)

    Valeur, Jørgen; Øines, Eliann; Morken, Mette Helvik;


    consecutive patients with functional abdominal complaints, referred to our clinic for investigation of self-reported food hypersensitivity, were included in the study and compared with 15 healthy volunteers. All subjects ingested a mixture of 25 g fructose and 5 g sorbitol. Pulmonary hydrogen and methane...... excretion and plasma glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) levels were measured during the next 3 h. Both habitual and post-test symptoms were assessed. RESULTS: Malabsorption of fructose and sorbitol was present in 61% of the patients and 73% of the controls. Nevertheless, the patients...... intolerance in patients with self-reported food hypersensitivity. Other mechanisms related to bacterial fermentation may be involved and should be investigated further....

  1. Elevated copper levels during larval development cause altered locomotor behavior in the adult carabid beetle Pterostichus cupreus L. (Coleoptera: Carbidae)

    DEFF Research Database (Denmark)

    Bayley, M; Baatrup, E; Heimbach, U


    It is generally believed that copper causes changes in carabid communities indirectly by reducing food availability, because these animals are frequently found to have only slightly elevated metal contents even close to pollution sources. Using computer-centered video tracking, the locomotor...... behavior of adult Pterostichus cupreus carabid beetles was quantified after being raised on copper-contaminated food and soil during larval development. Copper was found to have an acute toxic effect measured in larval mortality, to cause a slight increase in the developmental period of males......, but not to effect the emergence weights of adults of either sex. This toxic effect on the larvae was preserved through pupation to the surviving adults, which were normal in size and appearance, but displayed a dramatically depressed locomotor behavior. Copper analysis of these adults revealed that copper levels...

  2. Toxicity of canavanine in tomato (Solanum lycopersicum L.) roots is due to alterations in RNS, ROS and auxin levels. (United States)

    Krasuska, Urszula; Andrzejczak, Olga; Staszek, Paweł; Borucki, Wojciech; Gniazdowska, Agnieszka


    Canavanine (CAN) is non-proteinogenic aminoacid and a structural analog of arginine (Arg). Naturally, CAN occurs in legumes e.g. jack bean and is considered as a strong allelochemical. As a selective inhibitor of inducible nitric oxide synthase in mammalians, it could act as a modifier of nitric oxide (NO) concentration in plants. Modifications in the content of endogenous reactive nitrogen species (RNS) and reactive oxygen species (ROS) influence root structure and architecture, being also under hormonal control. The aim of the work was to investigate regulation of root growth in tomato (Solanum lycopersicum L. cv. Malinowy Ożarowski) seedling by application of CAN at concentration (10 and 50 μM) leading to 50% or 100% restriction of root elongation. CAN at higher concentration led to slight DNA fragmentation, increased total RNA and protein level. Decline in total respiration rate after CAN supplementation was not associated with enhanced membrane permeability. Malformations in root morphology (shorter and thicker roots, limited number of lateral roots) were accompanied by modification in NO and ONOO(-) localization; determined mainly in peridermal cells and some border cells. Although, CAN resulted in low RNS production, addition of exogenous NO by usage of NO donors did not reverse its negative effect, nor recovery effect was detected after roots imbibition in Arg. To build up a comprehensive view on mode of action of CAN as root growth inhibitor, it was shown an elevated level of auxin. To summarize, we demonstrated several secondary mode of action of CAN, indicating its toxicity in plants linked to restriction in RNS formation accompanied by simultaneous overaccumulation of ROS.

  3. Natural functional SNPs in miR-155 alter its expression level, blood cell counts and immune responses

    Directory of Open Access Journals (Sweden)

    Congcong Li


    Full Text Available miR-155 has been confirmed to be a key factor in immune responses in humans and other mammals. Therefore, investigation of variations in miR-155 could be useful for understanding the differences in immunity between individuals. In this study, four SNPs in miR-155 were identified in mice (Mus musculus and humans (Homo sapiens. In mice, the four SNPs were closely linked and formed two miR-155 haplotypes (A and B. Ten distinct types of blood parameters were associated with miR-155 expression under normal conditions. Additionally, 4 and 14 blood parameters were significantly different between these two genotypes under normal and lipopolysaccharide (LPS stimulation conditions, respectively. Moreover, the expression levels of miR-155, the inflammatory response to LPS stimulation and the lethal ratio following Salmonella typhimurium infection were significantly increased in mice harboring the AA genotype. Further, two SNPs, one in the loop region and the other near the 3' terminal of pre-miR-155, were confirmed to be responsible for the differential expression of miR-155 in mice. Interestingly, two additional SNPs, one in the loop region and the other in the middle of miR-155*, modulated the function of miR-155 in humans. Predictions of secondary RNA structure using RNAfold showed that these SNPs affected the structure of miR-155 in both mice and humans. Our results provide novel evidence of the natural functional SNPs of miR-155 in both mice and humans, which may affect the expression levels of mature miR-155 by modulating its secondary structure. The SNPs of human miR-155 may be considered as causal mutations for some immune-related diseases in the clinic. The two genotypes of mice could be used as natural models for studying the mechanisms of immune diseases caused by abnormal expression of miR-155 in humans.

  4. Altered circulating levels of matrix metalloproteinases and inhibitors associated with elevated type 2 cytokines in lymphatic filarial disease.

    Directory of Open Access Journals (Sweden)

    Rajamanickam Anuradha

    Full Text Available BACKGROUND: Infection with Wuchereria bancrofti can cause severe disease characterized by subcutaneous fibrosis and extracellular matrix remodeling. Matrix metalloproteinases (MMPs are a family of enzymes governing extracellular remodeling by regulating cellular homeostasis, inflammation, and tissue reorganization, while tissue-inhibitors of metalloproteinases (TIMPs are endogenous regulators of MMPs. Homeostatic as well as inflammation-induced balance between MMPs and TIMPs is considered critical in mediating tissue pathology. METHODS: To elucidate the role of MMPs and TIMPs in filarial pathology, we compared the plasma levels of a panel of MMPs, TIMPs, other pro-fibrotic factors, and cytokines in individuals with chronic filarial pathology with (CP Ag+ or without (CP Ag- active infection to those with clinically asymptomatic infections (INF and in those without infection (endemic normal [EN]. Markers of pathogenesis were delineated based on comparisons between the two actively infected groups (CP Ag+ compared to INF and those without active infection (CP Ag- compared to EN. RESULTS AND CONCLUSION: Our data reveal that an increase in circulating levels of MMPs and TIMPs is characteristic of the filarial disease process per se and not of active infection; however, filarial disease with active infection is specifically associated with increased ratios of MMP1/TIMP4 and MMP8/TIMP4 as well as with pro-fibrotic cytokines (IL-5, IL-13 and TGF-β. Our data therefore suggest that while filarial lymphatic disease is characterized by a non-specific increase in plasma MMPs and TIMPs, the balance between MMPs and TIMPs is an important factor in regulating tissue pathology during active infection.

  5. The C-terminal domains of the GABA(b) receptor subunits mediate intracellular trafficking but are not required for receptor signaling. (United States)

    Calver, A R; Robbins, M J; Cosio, C; Rice, S Q; Babbs, A J; Hirst, W D; Boyfield, I; Wood, M D; Russell, R B; Price, G W; Couve, A; Moss, S J; Pangalos, M N


    GABA(B) receptors are G-protein-coupled receptors that mediate slow synaptic inhibition in the brain and spinal cord. These receptors are heterodimers assembled from GABA(B1) and GABA(B2) subunits, neither of which is capable of producing functional GABA(B) receptors on homomeric expression. GABA(B1,) although able to bind GABA, is retained within the endoplasmic reticulum (ER) when expressed alone. In contrast, GABA(B2) is able to access the cell surface when expressed alone but does not couple efficiently to the appropriate effector systems or produce any detectable GABA-binding sites. In the present study, we have constructed chimeric and truncated GABA(B1) and GABA(B2) subunits to explore further GABA(B) receptor signaling and assembly. Removal of the entire C-terminal intracellular domain of GABA(B1) results in plasma membrane expression without the production of a functional GABA(B) receptor. However, coexpression of this truncated GABA(B1) subunit with either GABA(B2) or a truncated GABA(B2) subunit in which the C terminal has also been removed is capable of functional signaling via G-proteins. In contrast, transferring the entire C-terminal tail of GABA(B1) to GABA(B2) leads to the ER retention of the GABA(B2) subunit when expressed alone. These results indicate that the C terminal of GABA(B1) mediates the ER retention of this protein and that neither of the C-terminal tails of GABA(B1) or GABA(B2) is an absolute requirement for functional coupling of heteromeric receptors. Furthermore although GABA(B1) is capable of producing GABA-binding sites, GABA(B2) is of central importance in the functional coupling of heteromeric GABA(B) receptors to G-proteins and the subsequent activation of effector systems.

  6. Glutamate alteration of glutamic acid decarboxylase (GAD) in GABAergic neurons: the role of cysteine proteases. (United States)

    Monnerie, Hubert; Le Roux, Peter D


    Brain cell vulnerability to neurologic insults varies greatly, depending on their neuronal subpopulation. Among cells that survive a pathological insult such as ischemia or brain trauma, some may undergo morphological and/or biochemical changes that could compromise brain function. We previously reported that surviving cortical GABAergic neurons exposed to glutamate in vitro displayed an NMDA receptor (NMDAR)-mediated alteration in the levels of the GABA synthesizing enzyme glutamic acid decarboxylase (GAD65/67) [Monnerie, H., Le Roux, P., 2007. Reduced dendrite growth and altered glutamic acid decarboxylase (GAD) 65- and 67-kDa isoform protein expression from mouse cortical GABAergic neurons following excitotoxic injury in vitro. Exp. Neurol. 205, 367-382]. In this study, we examined the mechanisms by which glutamate excitotoxicity caused a change in cortical GABAergic neurons' GAD protein levels. Removing extracellular calcium prevented the NMDAR-mediated decrease in GAD protein levels, measured using Western blot techniques, whereas inhibiting calcium entry through voltage-gated calcium channels had no effect. Glutamate's effect on GAD protein isoforms was significantly attenuated by preincubation with the cysteine protease inhibitor N-Acetyl-L-Leucyl-L-Leucyl-L-norleucinal (ALLN). Using class-specific protease inhibitors, we observed that ALLN's effect resulted from the blockade of calpain and cathepsin protease activities. Cell-free proteolysis assay confirmed that both proteases were involved in glutamate-induced alteration in GAD protein levels. Together these results suggest that glutamate-induced excitotoxic stimulation of NMDAR in cultured cortical neurons leads to altered GAD protein levels from GABAergic neurons through intracellular calcium increase and protease activation including calpain and cathepsin. Biochemical alterations in surviving cortical GABAergic neurons in various disease states may contribute to the altered balance between excitation

  7. GABA receptor subunit composition relative to insecticide potency and selectivity. (United States)

    Ratra, G S; Casida, J E


    Three observations on the 4-[(3)H]propyl-4'-ethynylbicycloorthobenzoate ([(3)H]EBOB) binding site in the gamma-aminobutyric acid (GABA) receptor indicate the specific target for insecticide action in human brain and a possible mechanism for selectivity. First, from published data, alpha-endosulfan, lindane and fipronil compete for the [(3)H]EBOB binding site with affinities of 0.3--7 nM in both human recombinant homooligomeric beta 3 receptors and housefly head membranes. Second, from structure-activity studies, including new data, GABAergic insecticide binding potency on the pentameric receptor formed from the beta 3 subunit correlates well with that on the housefly receptor (r=0.88, n=20). This conserved inhibitor specificity is consistent with known sequence homologies in the housefly GABA receptor and the human GABA(A) receptor beta 3 subunit. Third, as mostly new findings, various combinations of alpha 1, alpha 6, and gamma 2 subunits coexpressed with a beta 1 or beta 3 subunit confer differential insecticide binding sensitivity, particularly to fipronil, indicating that subunit composition is a major factor in insecticide selectivity.

  8. Tris(2-butoxyethyl)phosphate and triethyl phosphate alter embryonic development, hepatic mRNA expression, thyroid hormone levels, and circulating bile acid concentrations in chicken embryos

    Energy Technology Data Exchange (ETDEWEB)

    Egloff, Caroline [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Crump, Doug, E-mail: [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Porter, Emily; Williams, Kim L.; Letcher, Robert J.; Gauthier, Lewis T. [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Kennedy, Sean W. [National Wildlife Research Centre, Environment Canada, Ottawa, ON K1A 0H3 (Canada); Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5 (Canada)


    The organophosphate flame retardants tris(2-butoxyethyl) phosphate (TBOEP) and triethyl phosphate (TEP) are used in a wide range of applications to suppress or delay the ignition and spread of fire. Both compounds have been detected in the environment and TBOEP was recently measured in free-living avian species. In this study, TBOEP and TEP were injected into the air cell of chicken embryos at concentrations ranging from 0 to 45,400 ng/g and 0 to 241,500 ng/g egg, respectively. Pipping success, development, hepatic mRNA expression of 9 target genes, thyroid hormone levels, and circulating bile acid concentrations were determined. Exposure to the highest doses of TBOEP and TEP resulted in negligible detection of the parent compounds in embryonic contents at pipping indicating their complete metabolic degradation. TBOEP exposure had limited effects on chicken embryos, with the exception of hepatic CYP3A37 mRNA induction. TEP exposure decreased pipping success to 68%, altered growth, increased liver somatic index (LSI) and plasma bile acids, and modulated genes associated with xenobiotic and lipid metabolism and the thyroid hormone pathway. Plasma thyroxine levels were decreased at all TEP doses, including an environmentally-relevant concentration (8 ng/g), and gallbladder hypotrophy was evident at ≥ 43,200 ng/g. Tarsus length and circulating thyroxine concentration emerged as potential phenotypic anchors for the modulation of transthyretin mRNA. The increase in plasma bile acids and LSI, gallbladder hypotrophy, and discoloration of liver tissue represented potential phenotypic outcomes associated with modulation of hepatic genes involved with xenobiotic and lipid metabolism. - Highlights: • TBOEP is not embryolethal to chicken embryos. • TEP affected embryonic viability, morphometric endpoints, and thyroid hormone levels. • TEP altered mRNA levels of xenobiotic and lipid metabolism genes. • TEP increased plasma bile acids and caused gallbladder hypotrophy

  9. Power of the policy: how the announcement of high-stakes clinical examination altered OSCE implementation at institutional level

    Directory of Open Access Journals (Sweden)

    Lin Chi-Wei


    Full Text Available Abstract Background The Objective Structured Clinical Examination (OSCE has been widely applied as a high-stakes examination for assessing physicians’ clinical competency. In 1992, OSCE was first introduced in Taiwan, and the authorities announced that passing the OSCE would be a prerequisite for step-2 medical licensure examination in 2013. This study aimed to investigate the impacts of the announced national OSCE policy on implementation of OSCE at the institutional level. Further, the readiness and the recognition of barriers toward a high-stakes examination were explored. Methods In 2007 and 2010, the year before and after the announcement of high-stakes OSCE policy in 2008, respectively, questionnaires on the status of OSCE implementation were distributed to all hospitals with active OSCE programs in Taiwan. Information on OSCE facilities, equipment, station length, number of administrations per year, and the recognition of barriers to the success of implementing an OSCE were collected. The missing data were completed by telephone interviews. The OSCE format, administration, and facilities before and after the announcement of the nationwide OSCE policy were compared. Results The data were collected from 17 hospitals in 2007 and 21 in 2010. Comparing the OSCE formats between 2007 and 2010, the number of stations increased and the station length decreased. The designated space and the equipment for OSCE were also found to have been improved. As for the awareness of OSCE implementation barriers, the hospital representatives concerned mostly about the availability and quality of standardized patients in 2007, as well as space and facilities in 2010. Conclusions The results of this study underscored an overall increase in the number of OSCE hospitals and changes in facilities and formats. While recruitment and training of standardized patients were the major concerns before the official disclosure of the policy, space and facilities became the

  10. Calmodulin binding to glutamate decarboxylase is required for regulation of glutamate and GABA metabolism and normal development in plants. (United States)

    Baum, G; Lev-Yadun, S; Fridmann, Y; Arazi, T; Katsnelson, H; Zik, M; Fromm, H


    Glutamate decarboxylase (GAD) catalyzes the decarboxylation of glutamate to CO2 and gamma-aminobutyrate (GABA). GAD is ubiquitous in prokaryotes and eukaryotes, but only plant GAD has been shown to bind calmodulin (CaM). Here, we assess the role of the GAD CaM-binding domain in vivo. Transgenic tobacco plants expressing a mutant petunia GAD lacking the CaM-binding domain (GADdeltaC plants) exhibit severe morphological abnormalities, such as short stems, in which cortex parenchyma cells fail to elongate, associated with extremely high GABA and low glutamate levels. The morphology of transgenic plants expressing the full-length GAD (GAD plants) is indistinguishable from that of wild-type (WT) plants. In WT and GAD plant extracts, GAD activity is inhibited by EGTA and by the CaM antagonist trifluoperazine, and is associated with a CaM-containing protein complex of approximately 500 kDa. In contrast, GADdeltaC plants lack normal GAD complexes, and GAD activity in their extracts is not affected by EGTA and trifluoperazine. We conclude that CaM binding to GAD is essential for the regulation of GABA and glutamate metabolism, and that regulation of GAD activity is necessary for normal plant development. This study is the first to demonstrate an in vivo function for CaM binding to a target protein in plants.

  11. Mathematical Identification of a Neuronal Network Consisting of GABA and DA in Striatal Slices of the Rat Brain

    Directory of Open Access Journals (Sweden)

    L. Ramrath


    Full Text Available High frequency stimulation (HFS has been used to treat various neurological and psychiatric diseases. Although further disorders are under investigation to extend the clinical application of HFS, the complex effect of HFS within a neuronal network is still unknown. Thus, it would be desirable to find a theoretical model that allows an estimation of the expected effect of applied HFS. Based on the neurochemical analysis of effects of the γ-aminobutyric acid (GABAA receptor antagonist bicuculline, the D2-like receptor antagonist sulpiride and the D1-like receptor antagonist SCH-23390 on HFS evoked GABA and dopamine (DA release from striatal slices of the rat brain, a mathematical network model is proposed including the neurotransmitters GABA, DA and glutamate (GLU. The model reflects inhibitory and excitatory interactions of the neurotransmitters outflow in the presence of HFS. Under the assumption of linear interactions and static measurements, the model is expressed analytically. Numerical identification of inhibition and excitation is performed on a basis of real outflow levels of GABA and DA in the rat striatum. Results validate the nature of the proposed model. Therefore, this leads to an analytical model of the interactions within distinct neural network components of the rat striatum.

  12. GABA and Endocannabinoids Mediate Depotentiation of Schaffer Collateral Synapses Induced by Stimulation of Temperoammonic Inputs.

    Directory of Open Access Journals (Sweden)

    Yukitoshi Izumi

    Full Text Available Long-term potentiation (LTP of Schaffer collateral (SC synapses in the hippocampus is thought to play a key role in episodic memory formation. Because the hippocampus is a shorter-term, limited capacity storage system, repeated bouts of learning and synaptic plasticity require that SC synapses reset to baseline at some point following LTP. We previously showed that repeated low frequency activation of temperoammonic (TA inputs to the CA1 region depotentiates SC LTP without persistently altering basal transmission. This heterosynaptic depotentiation involves adenosine A1 receptors but not N-methyl-D-aspartate receptors, metabotropic glutamate receptors or L-type calcium channels. In the present study, we used rat hippocampal slices to explore other messengers contributing to TA-induced SC depotentiation, and provide evidence for the involvement of cannabinoid-1 and γ-aminobutyric acid (GABA type-A receptors as more proximal signaling events leading to synaptic resetting, with A1 receptor activation serving as a downstream event. Surprisingly, we found that TA-induced SC depotentiation is independent of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA/kainate glutamate receptors. We also examined the involvement of mitogen-activated protein kinases (MAPKs, and found a role for extracellular-signal related kinase 1/2 and p38 MAPK, but not c-Jun-N-terminal kinase. These results indicate that low frequency stimulation of TA inputs to CA1 activates a complex signaling network that instructs SC synaptic resetting. The involvement of GABA and endocannabinoids suggest mechanisms that could contribute to cognitive dysfunction associated with substance abuse and neuropsychiatric disorders.

  13. GABA and Endocannabinoids Mediate Depotentiation of Schaffer Collateral Synapses Induced by Stimulation of Temperoammonic Inputs. (United States)

    Izumi, Yukitoshi; Zorumski, Charles F


    Long-term potentiation (LTP) of Schaffer collateral (SC) synapses in the hippocampus is thought to play a key role in episodic memory formation. Because the hippocampus is a shorter-term, limited capacity storage system, repeated bouts of learning and synaptic plasticity require that SC synapses reset to baseline at some point following LTP. We previously showed that repeated low frequency activation of temperoammonic (TA) inputs to the CA1 region depotentiates SC LTP without persistently altering basal transmission. This heterosynaptic depotentiation involves adenosine A1 receptors but not N-methyl-D-aspartate receptors, metabotropic glutamate receptors or L-type calcium channels. In the present study, we used rat hippocampal slices to explore other messengers contributing to TA-induced SC depotentiation, and provide evidence for the involvement of cannabinoid-1 and γ-aminobutyric acid (GABA) type-A receptors as more proximal signaling events leading to synaptic resetting, with A1 receptor activation serving as a downstream event. Surprisingly, we found that TA-induced SC depotentiation is independent of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate glutamate receptors. We also examined the involvement of mitogen-activated protein kinases (MAPKs), and found a role for extracellular-signal related kinase 1/2 and p38 MAPK, but not c-Jun-N-terminal kinase. These results indicate that low frequency stimulation of TA inputs to CA1 activates a complex signaling network that instructs SC synaptic resetting. The involvement of GABA and endocannabinoids suggest mechanisms that could contribute to cognitive dysfunction associated with substance abuse and neuropsychiatric disorders.

  14. Embryonic and postnatal development of GABA, calbindin, calretinin, and parvalbumin in the mouse claustral complex. (United States)

    Dávila, José Carlos; Real, M Angeles; Olmos, Luis; Legaz, Isabel; Medina, Loreta; Guirado, Salvador


    We analyzed the development of immunoreactive expression patterns for the neurotransmitter gamma-aminobutyric acid (GABA) and the calcium-binding proteins calbindin, calretinin, and parvalbumin in the embryonic and postnatal mouse claustral complex. Each calcium-binding protein shows a different temporal and spatial pattern of development. Calbindin-positive cells start to be seen very early during embryogenesis and increase dramatically until birth, thus becoming the most abundant cell type during embryonic development, especially in the ventral pallial part of the claustrum. The distribution of calbindin neurons throughout the claustrum during embryonic development partly parallels that of GABA neurons, suggesting that at least part of the calbindin neurons of the claustral complex are GABAergic and originate in the subpallium. Parvalbumin cells, on the other hand, start to be seen only postnatally, and their number then increases while the density of calbindin neurons decreases. Based on calretinin expression in axons, the core/shell compartments of the dorsal claustrum start to be clearly seen at embryonic day 18.5 and may be related to the development of the thalamoclaustral input. Comparison with the expression of Cadherin 8, a marker of the developing dorsolateral claustrum, indicates that the core includes a central part of the dorsolateral claustrum, whereas the shell includes a peripheral area of the dorsolateral claustrum, plus the adjacent ventromedial claustrum. The present data on the spatiotemporal developmental patterns of several subtypes of GABAergic neurons in the claustral complex may help for future studies on temporal lobe epilepsies, which have been related to an alteration of the GABAergic activity.

  15. The Alterations of Serum Cortisol Level and Blood Cell Count in Male Rats after a Short Term Exposure to Burned Radioactive Lantern Mantle Powder

    Directory of Open Access Journals (Sweden)

    Rezaeian Mohsen


    Full Text Available Background: Most lantern mantles contain low levels of radioactive thorium. Although radioactive lantern mantles present a minimal radiation health hazard, it is generally believed when inhaled or ingested, it can be dangerous. The purpose of this study was to assess the effect of short term exposure to radioactive lantern mantle on serum cortisol level and blood count.Materials and Methods: This experimental study was conducted in 2007-2009 in the school of medicine of Rafsanjan University of Medical Sciences. Twenty eight rats were divided randomly into two groups of 14 animals each. The first group was exposed to 600 mg burned radioactive lantern mantle powder (activity of 800Bq for 24 hours and inhaled radon released from mantles. The second group was exposed to non-radioactive lantern mantle powder at the same interval. Paired t-test was used to evaluate the difference in the means of cortisol and blood cell count in both groups. P<0.05 was considered as the significance level.Results: Short term exposure of animals to radioactive lantern mantle powder led to a statistically significant decreased cortisol level, while no statistically significant decrease was found in animals that were exposed to non-radioactive mantle powder. Furthermore, a significant reduction was shown in post-exposure counts of WBC in the case group.Conclusions: Despite alteration of serum cortisol level, this study could not show stimulatory effects in some blood counts

  16. Long-term exposure to abnormal glucose levels alters drug metabolism pathways and insulin sensitivity in primary human hepatocytes (United States)

    Davidson, Matthew D.; Ballinger, Kimberly R.; Khetani, Salman R.


    Hyperglycemia in type 2 diabetes mellitus has been linked to non-alcoholic fatty liver disease, which can progress to inflammation, fibrosis/cirrhosis, and hepatocellular carcinoma. Understanding how chronic hyperglycemia affects primary human hepatocytes (PHHs) can facilitate the development of therapeutics for these diseases. Conversely, elucidating the effects of hypoglycemia on PHHs may provide insights into how the liver adapts to fasting, adverse diabetes drug reactions, and cancer. In contrast to declining PHH monocultures, micropatterned co-cultures (MPCCs) of PHHs and 3T3-J2 murine embryonic fibroblasts maintain insulin-sensitive glucose metabolism for several weeks. Here, we exposed MPCCs to hypo-, normo- and hyperglycemic culture media for ~3 weeks. While albumin and urea secretion were not affected by glucose level, hypoglycemic MPCCs upregulated CYP3A4 enzyme activity as compared to other glycemic states. In contrast, hyperglycemic MPCCs displayed significant hepatic lipid accumulation in the presence of insulin, while also showing decreased sensitivity to insulin-mediated inhibition of glucose output relative to a normoglycemic control. In conclusion, we show for the first time that PHHs exposed to hypo- and hyperglycemia can remain highly functional, but display increased CYP3A4 activity and selective insulin resistance, respectively. In the future, MPCCs under glycemic states can aid in novel drug discovery and mechanistic investigations.

  17. Alteration of behavior and monoamine levels attributable to Lactobacillus plantarum PS128 in germ-free mice. (United States)

    Liu, Wei-Hsien; Chuang, Hsiao-Li; Huang, Yen-Te; Wu, Chien-Chen; Chou, Geng-Ting; Wang, Sabrina; Tsai, Ying-Chieh


    Probiotics, defined as live bacteria or bacterial products, confer a significant health benefit to the host, including amelioration of anxiety-like behavior and psychiatric illnesses. Here we administered Lactobacillus plantarum PS128 (PS128) to a germ-free (GF) mouse model to investigate the impact of the gut-brain axis on emotional behaviors. First, we demonstrated that chronic administration of live PS128 showed no adverse effects on physical health. Then, we found that administration of live PS128 significantly increased the total distance traveled in the open field test and decreased the time spent in the closed arm in the elevated plus maze test, whereas the administration of PS128 had no significant effects in the depression-like behaviors of GF mice. Also, chronic live PS128 ingestion significantly increased the levels of both serotonin and dopamine in the striatum, but not in the prefrontal cortex or hippocampus. These results suggest that the chronic administration of PS128 is safe and could induce changes in emotional behaviors. The behavioral changes are correlated with the increase in the monoamine neurotransmitters in the striatum. These findings suggest that daily intake of the L. plantarum strain PS128 could improve anxiety-like behaviors and may be helpful in ameliorating neuropsychiatric disorders.

  18. Low level of selenium increases the efficacy of 24-epibrassinolide through altered physiological and biochemical traits of Brassica juncea plants. (United States)

    Naz, Fatima Salva; Yusuf, Mohammad; Khan, Tanveer A; Fariduddin, Qazi; Ahmad, Aqil


    This study was conducted to provide an insight into the effect of Se (through soil) induced changes in Brassica juncea plants in the presence and absence of 24-epibrassinolide (EBL; foliar). The Se treatments showed dual response, 10 μM of Se significantly increased growth, water relations, photosynthetic attributes along with carbonic anhydrase activity whereas its higher concentrations proved inhibitory in concentration dependent manner. The follow-up application of EBL to the Se stressed plants improved growth, water relations, photosynthesis and simultaneously enhanced the various antioxidant enzymes viz. catalase, peroxidase and superoxide dismutase with the excess accumulation of proline. In addition to this, 10 μM Se increases the efficacy of 10(-8) M of EBL and both in combination showed maximum increase for the growth and photosynthetic traits of plants. On the other hand, the elevated level of antioxidant enzymes as well as proline could have conferred tolerance to the Se-stressed plants resulting in improved growth, water relations and photosynthesis.

  19. Effect of GABA on sperm acrosome reation in antisperm antibody positive patients

    Institute of Scientific and Technical Information of China (English)

    BianSL; ZhanW


    Objective:To investigate the effect of gamma-aminobutyric acid(GABA) on the rate of sperm acrosome reaction both in normal and antisperm antibody (AsAb) porsitive men.Methods:the sperm acrosome reaction was tested with triplestain technique in two groups of 18 men each.Results:(1)GABA increased the rate of sperm acrosome reaction both in normal and AsAb positive subjects(P<0.01);(2) GABA increased the Na+-K+-ATPase activity of sperm(P<0.01);(3)GABA increased the Ca2+-ATPase activity of sperm (P<0.05);(4)GABA decreased the production of MDA and oxygen free radicals of sperm.conclusion:GABA could regulate the rate of sperm acrosome reaction.

  20. Aldehyde dehydrogenase 1a1 mediates a GABA synthesis pathway in midbrain dopaminergic neurons. (United States)

    Kim, Jae-Ick; Ganesan, Subhashree; Luo, Sarah X; Wu, Yu-Wei; Park, Esther; Huang, Eric J; Chen, Lu; Ding, Jun B


    Midbrain dopamine neurons are an essential component of the basal ganglia circuitry, playing key roles in the control of fine movement and reward. Recently, it has been demonstrated that γ-aminobutyric acid (GABA), the chief inhibitory neurotransmitter, is co-released by dopamine neurons. Here, we show that GABA co-release in dopamine neurons does not use the conventional GABA-synthesizing enzymes, glutamate decarboxylases GAD65 and GAD67. Our experiments reveal an evolutionarily conserved GABA synthesis pathway mediated by aldehyde dehydrogenase 1a1 (ALDH1a1). Moreover, GABA co-release is modulated by ethanol (EtOH) at concentrations seen in blood alcohol after binge drinking, and diminished ALDH1a1 leads to enhanced alcohol consumption and preference. These findings provide insights into the functional role of GABA co-release in midbrain dopamine neurons, which may be essential for reward-based behavior and addiction.

  1. Prospective frequency correction for macromolecule-suppressed GABA editing at 3T

    DEFF Research Database (Denmark)

    Edden, Richard A E; Oeltzschner, Georg; Harris, Ashley D;


    PURPOSE: To investigate the effects of B0 field offsets and drift on macromolecule (MM)-suppressed GABA-editing experiments, and to implement and test a prospective correction scheme. "Symmetric" editing schemes are proposed to suppress unwanted coedited MM signals in GABA editing. MATERIALS...... AND METHODS: Full density-matrix simulations of both conventional (nonsymmetric) and symmetric MM-suppressed editing schemes were performed for the GABA spin system to evaluate their offset-dependence. Phantom and in vivo (15 subjects at 3T) GABA-edited experiments with symmetrical suppression of MM signals...... were performed to quantify the effects of field offsets on the total GABA+MM signal (designated GABA+). A prospective frequency correction method based on interleaved water referencing (IWR) acquisitions was implemented and its experimental performance evaluated during positive and negative drift...

  2. Molecular basis of the alternative recruitment of GABA(A) versus glycine receptors through gephyrin

    DEFF Research Database (Denmark)

    Maric, Hans-Michael; Kasaragod, Vikram Babu; Hausrat, Torben Johann;


    γ-Aminobutyric acid type A and glycine receptors (GABA(A)Rs, GlyRs) are the major inhibitory neurotransmitter receptors and contribute to many synaptic functions, dysfunctions and human diseases. GABA(A)Rs are important drug targets regulated by direct interactions with the scaffolding protein ge...... of GABA(A)Rs offers a framework for future investigations into the regulation of inhibitory synaptic strength and for the development of mechanistically and therapeutically relevant compounds targeting the gephyrin-GABA(A)R interaction.......γ-Aminobutyric acid type A and glycine receptors (GABA(A)Rs, GlyRs) are the major inhibitory neurotransmitter receptors and contribute to many synaptic functions, dysfunctions and human diseases. GABA(A)Rs are important drug targets regulated by direct interactions with the scaffolding protein...

  3. Distribution of GABA-like immunoreactivity in the rat amygdaloid complex. (United States)

    Nitecka, L; Ben-Ari, Y


    The distribution of GABA-like (GABA-Li) immunoreactivity in the rat amygdaloid complex was studied by using an anti-GABA antibody. GABA-Li positive neurons and processes were present in every nucleus of the complex. Three patterns of immunoreactivity were revealed: (1) the intercalated masses and the lateral olfactory tract nucleus exhibited the most intense staining of the neuropil, and virtually every neuron was labeled, (2) the central and medial nuclei contained intensely labeled neuropil and moderately labeled neurons, and (3) in the remaining nuclei, the neuropil was weakly labeled, and relatively numerous GABA-Li neurons were present. Our results suggest that: (1) the intercalated masses and lateral olfactory tract nucleus consist of large aggregates of GABA-Li immunoreactive neurons, and (2) the lateral, basal dorsal, and the posterior cortical nuclei may constitute a significant source of GABAergic connections to other amygdaloid nuclei, in particular to the medial and central nuclei.

  4. Association of GABA(B) receptors and members of the 14-3-3 family of signaling proteins. (United States)

    Couve, A; Kittler, J T; Uren, J M; Calver, A R; Pangalos, M N; Walsh, F S; Moss, S J


    Two GABA(B) receptors, GABA(B)R1 and GABA(B)R2, have been cloned recently. Unlike other G protein-coupled receptors, the formation of a heterodimer between GABA(B)R1 and GABA(B)R2 is required for functional expression. We have used the yeast two hybrid system to identify proteins that interact with the C-terminus of GABA(B)R1. We report a direct association between GABA(B) receptors and two members of the 14-3-3 protein family, 14-3-3eta and 14-3-3zeta. We demonstrate that the C-terminus of GABA(B)R1 associates with 14-3-3zeta in rat brain preparations and tissue cultured cells, that they codistribute after rat brain fractionation, colocalize in neurons, and that the binding site overlaps partially with the coiled-coil domain of GABA(B)R1. Furthermore we show a reduced interaction between the C-terminal domains of GABA(B)R1 and GABA(B)R2 in the presence of 14-3-3. The results strongly suggest that GABA(B)R1 and 14-3-3 associate in the nervous system and begin to reveal the signaling complexities of the GABA(B)R1/GABA(B)R2 receptor heterodimer.

  5. Estradiol-induced modulation of estrogen receptor-beta and GABA within the adult neocortex: a potential transsynaptic mechanism for estrogen modulation of BDNF. (United States)

    Blurton-Jones, Mathew; Tuszynski, Mark H


    Estrogen influences brain-derived neurotrophic factor (BDNF) expression in the neocortex. However, BDNF-producing cortical neurons do not express detectable levels of nuclear estrogen receptors; instead, the most abundant cortical nuclear estrogen receptor, ER-beta, is present in GABAergic neurons, prompting us to test the hypothesis that estrogen effects on BDNF are mediated via cortical inhibitory interneurons. Adult female ovariectomized rats were provided acute estrogen replacement and the number of cortical GABA, ER-beta, and ER-beta/GABA double-labeled neurons was examined. Within 48 hours of injection of 17-beta-estradiol, the number of perirhinal neurons double-labeled for ER-beta/GABA was reduced by 28% (PBDNF-expressing cells, brain sections were double- or triple-labeled for ER-beta, GABAergic, and BDNF immunomarkers. The findings indicated that ER-beta-bearing inhibitory neurons project onto other GABAergic neurons that lack nuclear estrogen receptors; these inhibitory neurons in turn innervate BDNF-expressing excitatory cells. High estrogen states reduce cortical GABA levels, presumably releasing inhibition on BDNF-expressing neurons. This identifies a putative two-step transsynaptic mechanism whereby estrogen availability modulates expression of inhibitory transmitters, resulting in increased BDNF expression.

  6. Early loss of interneurons and delayed subunit-specific changes in GABA(A)-receptor expression in a mouse model of mesial temporal lobe epilepsy. (United States)

    Bouilleret, V; Loup, F; Kiener, T; Marescaux, C; Fritschy, J M


    Unilateral injection of kainic acid (KA) into the dorsal hippocampus of adult mice induces spontaneous recurrent partial seizures and replicates histopathological changes observed in human mesial temporal lobe epilepsy (MTLE) (Bouilleret V et al., Neuroscience 1999; 89:717-729). Alterations in pre- and postsynaptic components of GABAergic neurotransmission were investigated immunohistochemically at different time points (1-120 days) in this mouse model of MTLE. Markers of GABAergic interneurons (parvalbumin, calbindin-D28k, and calretinin), the type-1 GABA transporter (GAT1), and major GABA(A)-receptor subunits expressed in the hippocampal formation were analyzed. Acutely, KA injection produced a profound loss of hilar cells but only limited damage to CA1 and CA3 pyramidal cells. In addition, parvalbumin and calbindin-D28k staining of interneurons disappeared irreversibly in CA1 and dentate gyrus (DG), whereas calretinin staining was spared. The prominent GABA(A)-receptor alpha1 subunit staining of interneurons also disappeared after KA treatment, suggesting acute degeneration of these cells. Likewise, GAT1 immunoreactivity revealed degenerating terminals at 24 h post-KA in CA1 and DC and subsided almost completely thereafter. Loss of CA1 and, to a lesser extent, CA3 neurons became evident at 7-15 days post-KA. It was more accentuated after 1 month, accompanied by a corresponding reduction of GABA(A)-receptor staining. In contrast, DC granule cells were markedly enlarged and dispersed in the molecular layer and exhibited a prominent increase in GABA(A)-receptor subunit staining. After 4 months, the dorsal CA1 area was lost almost entirely, CA3 was reduced, and the DG represented most of the remaining dorsal hippocampal formation. No significant morphological alterations were detected contralaterally. These results suggest that loss of hilar cells and GABAergic neurons contributes to epileptogenesis in this model of MTLE. In contrast, long-term degeneration of

  7. Human cerebrospinal fluid fatty acid levels differ between supernatant fluid and brain-derived nanoparticle fractions, and are altered in Alzheimer's disease.

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    Alfred N Fonteh

    Full Text Available Although saturated (SAFA, monounsaturated (MUFA, and polyunsaturated (PUFA fatty acids are important structural components of neuronal membranes and precursors of signaling molecules, knowledge of their metabolism in Alzheimer's disease (AD is limited. Based on recent discovery that lipids in cerebrospinal fluid (CSF are distributed in both brain-derived nanoparticles (NP and supernatant fluid (SF, we hypothesized that fatty acid (FA abundance and distribution into these compartments is altered in early AD pathology.We assayed the FA composition and abundance in CSF fractions from cognitively healthy (CH, mild cognitive impairment (MCI, and AD study participants using gas chromatography-mass spectrometry. In the SF fraction, concentration of docosahexaenoic acid [DHA, (C22:6n-3] was less in AD compared with CH, while alpha linolenic acid [α-LNA, (C18:3n-3] was lower in MCI compared with CH. In the NP fraction, levels of SAFAs (C15:0, C16:0 and a MUFA (C15:1 differentiated CH from MCI, while two MUFAs (C15:1, C19:1 and four PUFAs (C20:2n-6, C20:3n-3, C22:4n-6, C22:5n-3 were higher in AD compared with CH. Levels of even-chain free SAFA and total free FA levels were higher in AD, levels of odd-chain free SAFAs, MUFAs, n-3 PUFAs, and total PUFA, were lower in AD compared with CH. Free n-6 PUFA levels were similar in all three groups.FA metabolism is compartmentalized differently in NP versus SF fractions of CSF, and altered FA levels reflect the importance of abnormal metabolism and oxidative pathways in AD. Depleted DHA in CSF fractions in AD is consistent with the importance of n-3 PUFAs in cognitive function, and suggests that disturbed PUFA metabolism contributes to AD pathology. This study of FA levels in CSF fractions from different cognitive stages shows potential AD biomarkers, and provides further insight into cell membrane dysfunctions, including mechanisms leading to amyloid production.

  8. Allosteric modulation of GABA(B) receptor function in human frontal cortex. (United States)

    Olianas, Maria C; Ambu, Rossano; Garau, Luciana; Onali, Pierluigi


    In the present study, the effects of different allosteric modulators on the functional activity of gamma-aminobutyric acid (GABA)B receptors in membranes of post-mortem human frontal cortex were examined. Western blot analysis indicated that the tissue preparations expressed both GABA(B1) and GABA(B2) subunits of the GABA(B) receptor heterodimer. In [35S]-GTPgammaS binding assays, Ca2+ ion (1 mM) enhanced the potency of the agonists GABA and 3-aminopropylphosphinic acid (3-APA) and that of the antagonist CGP55845, but not that of the GABA(B) receptor agonist (-)-baclofen. CGP7930 (2,6-di-t-Bu-4-(3-hydroxy-2,2-dimethyl-propyl)-phenol), a positive allosteric modulator of GABA(B) receptors, potentiated both GABA(B) receptor-mediated stimulation of [35S]-GTPgammaS binding and inhibition of forskolin (FSK)-stimulated adenylyl cyclase activity. Chelation of Ca2+ ion by EGTA reduced the CGP7930 enhancement of GABA potency in stimulating [35S]-GTPgammaS binding by two-fold. Fendiline, also reported to act as a positive allosteric modulator of GABA(B) receptors, failed to enhance GABA stimulation of [35S]-GTPgammaS binding but inhibited the potentiating effect of CGP7930. The inhibitory effect was mimicked by the phenothiazine antipsychotic trifluoperazine (TFP), but not by other compounds, such as verapamil or diphenydramine (DPN). These data demonstrate that the function of GABA(B) receptors of human frontal cortex is positively modulated by Ca2+ ion and CGP7930, which interact synergistically. Conversely, fendiline and trifluoperazine negatively affect the allosteric regulation by CGP7930.

  9. Postnatal morphine administration alters hippocampal development in rats. (United States)

    Traudt, Christopher M; Tkac, Ivan; Ennis, Kathleen M; Sutton, Leah M; Mammel, Daniel M; Rao, Raghavendra


    Morphine is frequently used as an analgesic and sedative in preterm infants. Adult rats exposed to morphine have an altered hippocampal neurochemical profile and decreased neurogenesis in the dentate gyrus of the hippocampus. To evaluate whether neonatal rats are similarly affected, rat pups were injected twice daily with 2 mg/kg morphine or normal saline from postnatal days 3 to 7. On postnatal day 8, the hippocampal neurochemical profile was determined using in vivo (1)H NMR spectroscopy. The mRNA and protein concentrations of specific analytes were measured in hippocampus, and cell division in dentate gyrus was assessed using bromodeoxyuridine. The concentrations of γ-aminobutyric acid (GABA), taurine, and myo-insotol were decreased, whereas concentrations of glutathione, phosphoethanolamine, and choline-containing compounds were increased in morphine-exposed rats relative to control rats. Morphine decreased glutamic acid decarboxylase enzyme levels and myelin basic protein mRNA expression in the hippocampus. Bromodeoxyuridine labeling in the dentate gyrus was decreased by 60-70% in morphine-exposed rats. These results suggest that recurrent morphine administration during brain development alters hippocampal structure.

  10. THIP and isoguvacine are partial agonists of GABA-stimulated benzodiazepine receptor binding. (United States)

    Karobath, M; Lippitsch, M


    The effects of THIP and isoguvacine on 3H-flunitrazepam binding to washed membranes prepared from the cerebral cortex of adult rats have been examined. THIP, which has only minimal stimulatory effects on benzodiazepine (BZ) receptor binding, has been found to inhibit the stimulation induced by small concentrations (2 microM) of exogenous GABA. While isoguvacine stimulates BZ receptor binding, although to a smaller extent than GABA, it also antagonizes the stimulation of BZ receptor binding induced by GABA. Thus THIP and isoguvacine exhibit the properties of a partial agonist of GABA-stimulated BZ receptor binding.

  11. GABA(A) receptors on calbindin-immunoreactive myenteric neurons of guinea pig intestine. (United States)

    Zhou, X; Galligan, J J


    These studies were carried out to characterize the properties of gamma-aminobutyric acidA (GABA(A)) receptors on guinea pig intestinal myenteric neurons maintained in primary culture. In addition, the type of neuron expressing GABA(A) receptors was identified using immunohistochemical methods. Whole-cell patch clamp recordings of currents elicited by GABA and acetylcholine (ACh) were obtained using pipettes containing Neurobiotin. After electrophysiological studies, neurons were processed for localization of calbindin-D28K-immunoreactivity (calbindin-ir). GABA (1 mM) and ACh (3 mM) caused inward currents in most cells tested. GABA currents were mimicked by muscimol (1-300 microM) and were blocked by bicuculline (10 microM) indicating that GABA was acting at GABA(A) receptors. GABA currents were associated with a conductance increase and a linear current/voltage relationship with a reversal potential of 1 +/- 1 mV (n = 5). Pentobarbital (PB, 3-1000 microM) and diazepam (DZP, 0.01-10 microM) potentiated GABA-induced currents. A maximum concentration of DZP (1 microM) increased GABA-induced currents 3.1 +/- 0.3 times while PB (1000 microM) increased GABA currents by 11 +/- 2 times. In outside-out patches, the amplitude of GABA-activated single-channel currents was linearly related to membrane potential with a single-channel conductance of 28.5 + 0.5 pS (n = 10). PB and DZP increased the open probability of GABA-induced single-channel currents. Neurons containing calbindin-ir were large, were isolated from other neurons and had GABA current amplitudes of -3.4 +/- 0.3 nA (n = 48). Neurons with weak or absent calbindin-ir were smaller, were localized in clusters of cells and had GABA-induced current amplitudes of -0.6 +/- 0.1 nA (n = 20). ACh-induced currents were smaller in calbindin-ir neurons (-0.7 +/- 0.1 nA) compared to weakly calbindin-ir neurons (-1.4 +/- 0.1 nA). These results indicate that myenteric calbindin-ir neurons express a high density of GABA

  12. Pu-Erh tea and GABA attenuates oxidative stress in kainic acid-induced status epilepticus



    Abstract Background Pu-Erh tea is one of the most-consumed beverages due to its taste and the anti-anxiety-producing effect of the gamma-aminobutyric acid (GABA) if contains. However the protective effects of Pu-Erh tea and its constituent, GABA to kainic acid (KA)-induced seizure have not been fully investigated. Methods We analyzed the effect of Pu-Erh tea leaf (PETL) and GABA on KA-induced neuronal injury in vivo and in vitro. Results PETL and GABA reduced the maximal seizure classes, pred...

  13. Unique insecticide specificity of human homomeric rho 1 GABA(C) receptor. (United States)

    Ratra, Gurpreet S; Erkkila, Brian E; Weiss, David S; Casida, John E


    Several convulsants and major insecticides block the gamma-aminobutyric acid (GABA)-gated chloride channel in brain on binding to the GABA(A) receptor. The GABA(C) receptor, important in retina and present in brain, is also coupled to a chloride channel and is therefore a potential target for toxicant action examined here in radioligand binding and electrophysiological experiments. Human homomeric rho 1 GABA(C) receptor expressed in human embryonic kidney cells (HEK293) undergoes specific and saturable high-affinity binding of 4-n-[3H]propyl-4' -ethynylbicycloorthobenzoate ([3H]EBOB) using a cyano analog (CNBOB) to determine non-specific binding. This GABA(C) rho 1 receptor is very sensitive to CNBOB and lindane relative to alpha-endosulfan, tert-butylbicyclophosphorothionate, picrotoxinin and fipronil (IC(50) values of 23, 91, 800, 1080, 4000 and >10000 nM, respectively, in displacing [3H]EBOB). A similar potency sequence (except for picrotoxinin) is observed for inhibition of GABA-induced currents of rho 1 receptor expressed in Xenopus oocytes. The present study does not consider rho 2 homomeric and rho 1 rho 2 heteromeric GABA(C) receptors which are known to be more sensitive than rho 1 to picrotoxinin. The inhibitor sensitivity and specificity of this rho 1 GABA(C) receptor differ greatly from those of human homomeric beta 3 and native GABA(A) receptors.

  14. [GABA--the basic mediator of excitation in the early stages of hippocampal development]. (United States)

    Khazipov, R N; Zefirov, A L; Ben-Ari, E


    GABA is the principal neurotransmitter of inhibition in the adult mammalian brain. However, at early stages of development, including embryonic period and first week of postnatal life, GABA plays the role of main neurotransmitter of excitation. The paradoxical excitatory effect of GABA is due to an inversed chloride gradient and therefore a depolarizing direction of GABA-A receptor mediated responses. In addition, another type of GABAergic inhibition mediated by postsynaptic GABA-B receptors is not functional at early stage of life. In the neonatal rat hippocampus, GABA, acting via GABA-A receptors, activates voltage gated sodium and calcium channels and potentiates the activity of NMDA receptors by reducing their voltage dependent Mg2+ block. The temporal window when GABA exerts excitatory actions coincides with a particular pattern of activity of hippocampal neuronal network that is characterized by periodical giant depolarizing potentials (GDPs) reminiscent of interictal-like epileptiform discharges. Recent studies have shown that GDPs result from the synchronous discharge of GABAergic interneurons and principal glutamatergic pyramidal cells and are mediated by the synergistic excitatory actions of GABA-A and glutamate receptors. GDPs provide synchronous intracellular Ca2+ oscillations and may therefore be implicated in hebbian modulation of developing synapses and activity-dependent formation of the hippocampal network.

  15. Sodium-independent, bicuculline-sensitive (/sup 3/H)GABA binding to isolated rat hepatocytes

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    Minuk, G.Y.; Bear, C.E.; Sarjeant, E.J.


    To determine whether hepatocytes possess specific receptor sites for gamma-aminobutyric acid (GABA), a potent amino acid neurotransmitter, (/sup 3/H)GABA, was added to sodium-free suspensions of Percoll-purified hepatocytes derived from collagenase-perfused rat livers under various experimental conditions and in the presence or absence of specific GABA receptor agonists (muscimol) and antagonists (bicuculline). The effects of GABA, muscimol, and bicuculline on hepatocyte resting membrane potentials were also determined. Specific binding of (/sup 3/H)GABA to hepatocytes was a consistent finding. GABA-hepatocyte interactions were reversible and temperature dependent. Muscimol and bicuculline inhibited binding in a dose-dependent manner (IC50, 30 nM and 50 microM, respectively), whereas strychnine (1.0-100 microM), a nonspecific central nervous system stimulant, had no appreciable effect. Both GABA and muscimol (100 microM) caused significant hyperpolarization of hepatocyte resting membrane potential (delta PD 5.4 +/- 3.1 and 22.2 +/- 16.2 mV, respectively, means +/- SD, P less than 0.0005). Bicuculline (100 microM) inhibited the effect of muscimol (P less than 0.05). The results of this study suggest that specific GABA receptor sites exist on the surface of isolated rat hepatocytes. The presence of such sites raises the possibility that, in addition to adrenergic and cholinergic innervation, hepatic function may be influenced by GABA-ergic neurotransmitter mechanisms.

  16. A study on quality components and sleep-promoting effects of GABA black tea. (United States)

    Zhao, Wenfang; Li, Yun; Ma, William; Ge, Yazhong; Huang, Yahui


    The aims of this study were to analyze the changes in quality components of gamma (γ)-aminobutyric acid (GABA) black tea during processing, and to investigate the effect of three dosages of GABA black tea on sleep improvement. The results showed that the GABA content was increased significantly up to 2.70 mg g(-1) after vacuum anaerobic and aerobic treatment. In addition, the content of GABA after drying reached 2.34 mg g(-1), which achieved the standard of GABA tea. During the entire processing of GABA black tea, the contents of tea polyphenols, caffeine and total catechins displayed a gradually descending trend, while the contents of free amino acids and GABA were firstly increased, and then reduced. The GABA black tea had significant effects on prolonging the sleeping time with sodium pentobarbital (P 0.05). It had no effect on directly inducing sleep and the mouse body weight. The extract of GABA black tea improved the sleeping quality of mice to extend with an optimal effect being found in the high dose-treated mice.

  17. Ethanol during adolescence decreased the BDNF levels in the hippocampus in adult male Wistar rats, but did not alter aggressive and anxiety-like behaviors

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    Letícia Scheidt


    Full Text Available Objective:To investigate the effects of ethanol exposure in adolescent rats during adulthood by assesssing aggression and anxiety-like behaviors and measuring the levels of inflammatory markers.Methods:Groups of male Wistar rats (mean weight 81.4 g, n = 36 were housed in groups of four until postnatal day (PND 60. From PNDs 30 to 46, rats received one of three treatments: 3 g/kg of ethanol (15% w/v, orally, n = 16, 1.5 g/kg of ethanol (12.5% w/v, PO, n = 12, or water (n = 12 every 48 hours. Animals were assessed for aggressive behavior (resident x intruder test and anxiety-like behaviors (elevated plus maze during adulthood.Results:Animals that received low doses of alcohol showed reduced levels of brain-derived neurotrophic factor (BDNF in the hippocampus as compared to the control group. No significant difference was found in prefrontal cortex.Conclusions:Intermittent exposure to alcohol during adolescence is associated with lower levels of BDNF in the hippocampus, probably due the episodic administration of alcohol, but alcohol use did not alter the level agression toward a male intruder or anxiety-like behaviors during the adult phase.

  18. Dioxin exposure reduces the steroidogenic capacity of mouse antral follicles mainly at the level of HSD17B1 without altering atresia

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    Karman, Bethany N., E-mail:; Basavarajappa, Mallikarjuna S., E-mail:; Hannon, Patrick, E-mail:; Flaws, Jodi A., E-mail:


    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent ovarian toxicant. Previously, we demonstrated that in vitro TCDD (1 nM) exposure decreases production/secretion of the sex steroid hormones progesterone (P4), androstenedione (A4), testosterone (T), and 17β-estradiol (E2) in mouse antral follicles. The purpose of this study was to determine the mechanism by which TCDD inhibits steroidogenesis. Specifically, we examined the effects of TCDD on the steroidogenic enzymes, atresia, and the aryl hydrocarbon receptor (AHR) protein. TCDD exposure for 48 h increased levels of A4, without changing HSD3B1 protein, HSD17B1 protein, estrone (E1), T or E2 levels. Further, TCDD did not alter atresia ratings compared to vehicle at 48 h. TCDD, however, did down regulate the AHR protein at 48 h. TCDD exposure for 96 h decreased transcript levels for Cyp11a1, Cyp17a1, Hsd17b1, and Cyp19a1, but increased Hsd3b1 transcript. TCDD exposure particularly lowered both Hsd17b1 transcript and HSD17B1 protein. However, TCDD exposure did not affect levels of E1 in the media nor atresia ratings at 96 h. TCDD, however, decreased levels of the proapoptotic factor Bax. Collectively, these data suggest that TCDD exposure causes a major block in the steroidogenic enzyme conversion of A4 to T and E1 to E2 and that it regulates apoptotic pathways, favoring survival over death in antral follicles. Finally, the down‐regulation of the AHR protein in TCDD exposed follicles persisted at 96 h, indicating that the activation and proteasomal degradation of this receptor likely plays a central role in the impaired steroidogenic capacity and altered apoptotic pathway of exposed antral follicles. -- Highlights: ► TCDD disrupts steroidogenic enzymes in mouse antral follicles. ► TCDD particularly affects the HSD17B1 enzyme in mouse antral follicles. ► TCDD does not affect atresia ratings in mouse antral follicles. ► TCDD decreases levels of the proapoptitic factor Bax in mouse antral follicles.

  19. Studies on the potential neurotoxic and convulsant effects of increased blood levels of quinolinic acid in rats with altered blood-brain barrier permeability

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    Vezzani, A.; Stasi, M.A.; Wu, H.Q.; Castiglioni, M.; Weckermann, B.; Samanin, R. (Istituto di Ricerche Farmacologiche Mario Negri, Milano (Italy))


    Intravenous injection of 450 mg/kg quinolinic acid (Quin), an endogenous kynurenine metabolite with excitotoxic properties, induced only minor electroencephalographic (EEG) modifications and no neurotoxicity in rats with a mature blood-brain barrier (BBB). BBB permeability was altered in rats by focal unilateral irradiation of the cortex (7 mm in diameter and 5 mm in depth) with protons (60 Gy, 9 Gy/min). Three days after irradiation, Evans blue dye staining showed BBB breakdown in the dorsal hippocampus of the irradiated hemisphere. No neurotoxic or convulsant effects were observed as a consequence of the radiation itself. When BBB-lesioned rats were challenged with 225 mg/kg Quin iv, epileptiform activity was observed on EEG analysis. Tonic-clonic seizures were induced by 225-450 mg/kg Quin. Light microscopic analysis showed a dose-related excitotoxic type of lesion restricted to the hippocampus ipsilateral to the irradiated side. Neuro-degeneration was prevented by local injection of 120 nmol D(-)2-amino-7-phosphonoheptanoic acid, a selective N-methyl-D-aspartate receptor antagonist. No lesions or EEG or behavioral modifications occurred after 450 mg/kg nicotinic acid, an inactive analog of Quin. The potential neurotoxic and convulsant effects of increased blood levels of Quin under conditions of altered BBB permeability are discussed.

  20. Serosorting and Sexual Risk for HIV Infection at the Ego-Alter Dyadic Level: An Egocentric Sexual Network Study Among MSM in Nigeria. (United States)

    Rodriguez-Hart, Cristina; Liu, Hongjie; Nowak, Rebecca G; Orazulike, Ifeanyi; Zorowitz, Sam; Crowell, Trevor A; Baral, Stefan D; Blattner, William; Charurat, Man


    The objective of this egocentric network study was to investigate engagement in serosorting by HIV status and risk for HIV between seroconcordant and serodiscordant ego-alter dyads. Respondent-driving sampling was used to recruit 433 Nigerian men who have sex with men (MSM) from 2013 to 2014. Participant (ego) characteristics and that of five sex partners (alters) were collected. Seroconcordancy was assessed at the ego level and for each dyad. Among 433 egos, 18 % were seroconcordant with all partners. Among 880 dyads where participants knew their HIV status, 226 (25.7 %) were seroconcordant, with 11.7 % of HIV positive dyads seroconcordant and 37.0 % of HIV negative dyads seroconcordant. Seroconcordant dyads reported fewer casual sex partners, less partner concurrency, and partners who had ever injected drugs, but condom use did not differ significantly. Serosorting may be a viable risk reduction strategy among Nigerian MSM, but awareness of and communication about HIV status should be increased. Future studies should assess serosorting on a partner-by-partner basis.

  1. Hippocampal oscillations in the rodent model of schizophrenia induced by amygdala GABA receptor blockade

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    Tope eLanre-Amos


    Full Text Available Brain oscillations are critical for cognitive processes, and their alterations in schizophrenia have been proposed to contribute to cognitive impairments. Network oscillations rely upon GABAergic interneurons, which also show characteristic changes in schizophrenia. The aim of this study was to examine the capability of hippocampal networks to generate oscillations in a rat model previously shown to reproduce the stereotypic structural alterations of the hippocampal interneuron circuit seen in schizophrenic patients. This model uses injection of GABA-A receptor antagonist picrotoxin into the basolateral amygdala which causes cell-type specific disruption of interneuron signaling in the hippocampus. We found that after such treatment, hippocampal theta rhythm was still present during REM sleep, locomotion, and exploration of novel environment and could be elicited under urethane anesthesia. Subtle changes in theta and gamma parameters were observed in both preparations; specifically in the stimulus intensity—theta frequency relationship under urethane and in divergent reactions of oscillations at the two major theta dipoles in freely moving rats. Thus, theta power in the CA1 region was generally enhanced as compared with deep theta dipole which decreased or did not change. The results indicate that pathologic reorganization of interneurons that follows the over-activation of the amygdala-hippocampal pathway, as shown for this model of schizophrenia, does not lead to destruction of the oscillatory circuit but changes the normal balance of rhythmic activity in its various compartments.

  2. Ultrastructural examination of the corticocollicular pathway in the guinea pig: a study using electron microscopy, neural tracers, and GABA immunocytochemistry

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    Kyle T Nakamoto


    Full Text Available Projections from auditory cortex (AC can alter the responses of cells in the inferior colliculus (IC to sounds. Most IC cells show excitation and inhibition after stimulation of the AC. AC axons release glutamate and excite their targets, so inhibition is presumed to result from cortical activation of GABAergic IC cells that inhibit other IC cells via local projections. However, it is not known whether cortical axons contact GABAergic IC cells directly. We labeled corticocollicular axons by injecting fluorescent dextrans into the AC in guinea pigs. We visualized the tracer with diaminobenzidine and processed the tissue for electron microscopy. We identified presumptive GABAergic profiles with post-embedding anti-GABA immunogold histochemistry on ultrathin sections. We identified dextran-labeled cortical boutons in the IC and identified their postsynaptic targets according to morphology (e.g., spine, dendrite and GABA-reactivity. Cortical synapses were observed in all IC subdivisions, but were comparatively rare in the central nucleus. Cortical boutons contain round vesicles and few mitochondria. They form asymmetric synapses with spines (most frequently, dendritic shafts and, least often, with cell bodies. Excitatory boutons in the IC can be classified as large, medium or small; most cortical boutons belong to the small excitatory class, while a minority (~14% belong to the medium excitatory class. Approximately 4% of the cortical targets were GABA-positive; these included dendritic shafts, spines, and cell bodies.We conclude that the majority of cortical boutons contact non-GABAergic (i.e., excitatory IC cells and a small proportion (4% contact GABAergic cells. Given that most IC cells show inhibition (as well as excitation after cortical stimulation, it is likely that the majority of cortically-driven inhibition in the IC results from cortical activation of a relatively small number of IC GABAergic cells that have extensive local axons.

  3. Distribution of GABA-ergic Neurons in the Rhesus Monkey Substantia Nigra%猕猴黑质GABA能神经元的分布

    Institute of Scientific and Technical Information of China (English)

    董大翠; 蔡秋云; 姚大卫; 陈活彝


    The higher evolutive rhesus monkeys were used as experimental materials. GABA-ergic neurons were observed under a light microscope. The GABA-ergic neurons in the pars reticulata of substantion nigra were numerous, dominant in the shape of polygonal or shuttle. The GABA neurons in the pars compacta of substantia nigra were less than in the pars reticulata, with the shape dominant in polygonal, round or shuttle.Many GABA-like positive fibres were observed at the inferior colliculus level of substantia nigra.%采用进化程度较高的灵长类动物猕猴作为实验材料,在光镜下观察黑质的GABA能神经元。在黑质网状部GABA能神经元数量多,以多角形和梭形为主,致密部的GABA能神经元较网状部略稀少,胞体形态以多角形、圆形和梭形为主;在下丘平面还可见到许多GABA样阳性神经纤维。

  4. Effect of Heat Stress on the Expression of GABA Receptor mRNA in the HPG Axis of Wenchang Chickens

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