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Thymol, a constituent of thyme essential oil, is a positive allosteric modulator of human GABAA receptors and a homo-oligomeric GABA receptor from Drosophila melanogaster  

UK PubMed Central (United Kingdom)

The GABA-modulating and GABA-mimetic activities of the monoterpenoid thymol were explored on human GABAA and Drosophila melanogaster...Full Text Available

2003-12-01

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Factors affecting actions of ethanol on GABA-activated chloride channels  

International Nuclear Information System (INIS)

Effects of ethanol in vitro on membrane vesicles were evaluated by monitoring "3"6Cl"- influx. Different assay parameters were tested to determine increased or decreased action of ethanol on GABA-activated chloride channels. The ability of 30 mM ethanol to augment "3"6Cl"- flux was seen at 0 degree C, in the absence of GABA, and at 34 degree C in the presence of GABA, using two different assay procedures. Picrotoxin blocked the direct effects of ethanol suggesting GABA_a involvement. Endogenous GABA in the medium surrounding the microsacs was assayed at different temperatures both in the presence and absence of GABA and ethanol. The direct effect of ethanol did not appear to involve the action of endogenous GABA. In addition to temperature effects on the assay, time of membrane storage also influenced ethanol action. Microsacs stored on ice ...

3

Effects of cultivar and culture conditions on g-aminobutyric acid accumulation in germinated fava beans (Vicia faba L.)  

British Library Electronic Table of Contents (United Kingdom)

BACKGROUND: High levels of g-aminobutyric acid (GABA) accumulate in plant tissues under various stresses. GABA accumulation is also influenced by cultivar. This aim of this study was to select the most promising cultivar of fava bean for GABA accumulation and to optimise the culture conditions for GABA production in germinated fava beans by response surface methodology based on central composite design (CCD). RESULTS: GABA content and glutamate decarboxylase activity in germinated seeds of cultivar S2 were significantly higher than those in other cultivars (P < 0.05). A significant negative correlation (r = -0.765, P < 0.05) between germination percentage and 1000-kernel weight was observed. There was a linear relationship between GABA content and sprout length (R2 = 0.816). The regression...

2010-01-01

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Genetic Modulation of GABA Levels in the Anterior Cingulate Cortex by GAD1 and COMT  

UK PubMed Central (United Kingdom)

γ-Aminobutyric acid (GABA)-ergic transmission is critical for normal cortical function and is likely abnormal in a variety of neuropsychiatric disorders. We tested the in...Full Text Available

2010-07-01

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

DEFF Research Database (Denmark)

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. 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 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 ...

1987-01-01

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Zero net flux estimates of septal extracellular glucose levels and the effects of glucose on septal extracellular GABA levels  

UK PubMed Central (United Kingdom)

Although hippocampal infusions of glucose enhance memory, we have found repeatedly that septal glucose infusions impair memory when γ-aminobutyric acid (GABA) receptors are activated....Full Text Available

2009-06-02

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Neuroactive steroids have multiple actions to potentiate GABAA receptors  

UK PubMed Central (United Kingdom)

The effects of neuroactive steroids on the function of GABAA receptors were studied using cell-attached records of single channel activity recorded from HEK293 cells transfected with α1...Full Text Available

2004-07-01

8

Beyond Acid Suppression: New Pharmacologic Approaches for Treatment of GERD  

British Library Electronic Table of Contents (United Kingdom)

Proton pump inhibitors are highly successful in treating gastroesophageal reflux disease, but a significant proportion of patients have persistent symptoms from weakly or nonacidic reflux. Transient lower esophageal sphincter relaxation (TLESR) represents the dominant mechanism of gastroesophageal reflux and has therefore become the most intensely investigated therapeutic target. The triggering of TLESR involve the vagal pathways and the ?-aminobutyric type B (GABA(B)) and metabotropic glutamate type 5 (mGluR5) receptors. Baclofen is a GABA(B) receptor agonist that is effective in inhibiting TLESR and reducing the number of reflux episodes, but is associated with significant central nervous system (CNS) side effects. The newer GABA(B) agonists, such as AZD9343 and AZD3355, and mGluR5 antag...

2010-01-01

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Selective Excitatory Actions of DNQX and CNQX in Rat Thalamic Neurons  

UK PubMed Central (United Kingdom)

The thalamic reticular nucleus (TRN) consists of GABA-containing neurons that form reciprocal synaptic connections with thalamic relay nuclei. Excitatory synaptic innervation of TRN neurons arises from...Full Text Available

2010-04-01

10

New insights into purinergic receptor signaling in neuronal differentiation, neuroprotection, and brain disorders  

UK PubMed Central (United Kingdom)

Ionotropic P2X and metabotropic P2Y purinergic receptors are expressed in the central nervous system and participate in the synaptic process particularly associated with acetylcholine, GABA, and glutamate...Full Text Available

2007-09-01

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Long-term synaptic transformation of hippocampal CA1 gamma-aminobutyric acid synapses and the effect of anandamide.  

UK PubMed Central (United Kingdom)

Evidence is presented for a distinctive type of hippocampal synaptic modification [previously described for a molluscan gamma-aminobutyric acid (GABA) synapse after paired pre- and postsynaptic excitation]:...Full Text Available

1995-10-24

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Cerebrospinal fluid zinc concentrations in febrile convulsions.  

UK PubMed Central (United Kingdom)

Zinc modulates the activity of glutamic acid decarboxylase, the rate limiting enzyme in the synthesis of gamma-aminobutyric acid (GABA), which is a major inhibitory neurotransmitter. Low cerebrospinal...Full Text Available

1995-10-01

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The effect of ethanol on "3"5-S-TBPS binding to mouse brain membranes in the presence of chloride  

International Nuclear Information System (INIS)

The effect of in vitro and in vivo administration of ethanol on the binding of "3"5S-t-butyl-bicyclophosphorothionate ("3"5S-TBPS) to cortical brain membranes of C57B1 mice was investigated using KCl (100 mM) containing assay media. The in vitro addition of ethanol produced a dose-dependent inhibition of basal "3"5S-TBPS binding. In the presence of chloride ions, GABA and pentobarbital had a biphasic action (stimulation followed by inhibition) on "3"5S-TBPS binding, whereas diazepam only stimulated the binding. Ethanol reduced the stimulatory effects of GABA and pentobarbital in a dose-dependent manner, but had no effect on the enhancement of "3"5S-TBPS binding produced by diazepam. "3"5S-TBPS binding to cortical brain membranes was inhibited by the putative Cl"- channel blocking agent DIDS. This inhibitory action of DIDS was significantly, and dose-dependently reduced by ethanol (#<=# 100 mM ethanol). Chronic ethanol ingestion in vivo, ...

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Blockade of androgen receptors is sufficient to alter the sexual differentiation of the substantia nigra pars reticulata seizure-controlling network  

UK PubMed Central (United Kingdom)

The substantia nigra pars reticulata (SNR) controls seizures in a sex-specific manner. At postnatal day 15 (P15), SNR infusion of GABAA receptor agonist muscimol have proconvulsant...Full Text Available

2008-03-01

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

UK PubMed Central (United Kingdom)

Gonadotropin–releasing hormone (GnRH) neurons are the central regulators of reproduction. GABAergic transmission plays a critical role in pubertal activation of pulsatile GnRH secretion....Full Text Available

2010-05-12

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Protracted ethanol withdrawal in rats: Tolerance to the anxiolytic effects of diazepam and pentobarbital but not phenobarbital  

Science.gov (United States)

Anxiety is a common symptom during ethanol withdrawal contributing to its continuous abuse and alcoholism. Ethanol withdrawal in rats produces an interoceptive discriminative stimulus (IDS) similar to that produced by the anxiogenic drug pentylenetetrazol (PTZ). This stimulus peaks at 12 hours after last dose of ethanol and thereafter the IDS is detected for several days (protracted withdrawal) by sensitization to a probe drug. previously, the authors have shown that during the protracted withdrawal, the IDS is enhanced by GABA receptor antagonists suggesting alteration of brain GABA systems. This report provides further evidence that chronic ethanol alters GABAergic systems. Rats were trained to discriminate PTZ (20 mg/kg, ip) from saline. Diazepam, pentobarbital and phenobarbital blocked the PTZ-IDS dose dependently. Ethanol, 4.5% w/v, was then given in a nutritionally complete diet for a week. On termination of the ethanol diet, rats ...

1990-02-26

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Study of epileptiform activity in cerebral ganglion of mud crab Scylla serrata  

British Library Electronic Table of Contents (United Kingdom)

An attempt is made to induce in mud crab (Scylla serrata) epileptiform activities that resemble the generalized epileptic seizures. Cerebral ganglion of crab was exposed in situ, to a convulsant drug pentylenetetrazole (PTZ) 100?mM, for induction of seizures. Also, crabs were pretreated with antiepileptic drug viz sodium valproate (120??mol/l) to inhibit epileptiform activities. The surface electrical discharges of cerebral ganglion were recorded using Unkelscope (MIT, USA) in control as well as experimental animals. The cerebral ganglion of crab showed a pattern of high cerebral electrical discharges after PTZ treatment compared to control. The sodium valproate promoted sedative action in control and prevented PTZ-mediated epileptiform discharges. Glutamate and GABA contents in cerebral g...

2011-01-01

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Nerve growth factor actions on the brain  

International Nuclear Information System (INIS)

We examined the effect of the trophic protein, nerve growth factor (NGF), on cultures of fetal rat neostriatum and basal forebrain-medial septal area (BF-MS) to define its role in brain development. Treatment of cultures with NGF resulted in an increase in the specific activity of the cholinergic enzyme choline acetyltransferase (CAT) in both brain areas. CAT was immunocytochemically localized to neurons. In the BF-MS, NGF treatment elicited a marked increase in staining intensity and an apparent increase in the number of CAT-positive neurons. Moreover, treatment of BF-MS cultures with NGF increased the activity of acetylcholinesterase, suggesting that the cholinergic neuron as a whole was affected. To begin defining mechanisms of action of NGF in the BF-MS, we detected NGF receptors by two independent methods. Receptors were localized to two different cellular populations: neuron-like cells, and non-neuron-like cells. Dissociation studies with ["1"2"5I]NGF suggested that high affinity ...