Search results for "GABA receptor antagonist"
showing 6 items of 6 documents
Role of GABAergic antagonism in the neuroprotective effects of bilobalide
2006
Bilobalide, a constituent of Ginkgo biloba, has neuroprotective properties. Its mechanism of action is unknown but it was recently found to block GABA(A) receptors. The goal of this study was to test the potential role of a GABAergic mechanism for the neuroprotective activity of bilobalide. In rat hippocampal slices exposed to NMDA, release of choline indicates breakdown of membrane phospholipids. NMDA-induced choline release was almost completely blocked in the presence of bilobalide (10 microM) and under low-chloride conditions. Bicuculline (100 microM), a competitive antagonist at GABA(A) receptors, reduced NMDA-induced choline release to a small extent (-23%). GABA (100 microM) partiall…
Lateral habenula and hippocampus: A complex interaction raphe cells-mediated
1997
The study has shown an excitatory influence exerted by lateral habenula (LH) on hippocampal pyramidal cells. The modulatory influence is paradoxically serotonine-mediated; in fact all LH stimulation effects were abolished by intrahippocampal iontophoretic methysergide application. The data suggest the involvement of dorsal raphe nucleus. In fact, the dorsal raphe nucleus stimulation caused on hippocampus an expected inhibitory effect antagonized by intrahippocampal iontophoretic methysergide application. In the context of this neural structure we have highlighted a disinhibitory relation between two types of cells: slow serotonergic efferent neurones and fast GABAergic interneurones. The di…
Cholecystokinin-8 sulfate modulates the anticonvulsant efficacy of vigabatrin in an experimental model of partial complex epilepsy in the rat.
2009
Summary Purpose: We evaluated the possible additive effect induced by the administration of the anticonvulsant vigabatrin (VGB) and cholecystokinin-8 sulfate (CCK-8S) on an experimental model of partial complex seizures (maximal dentate gyrus activation, MDA). Moreover, the functional involvement of γ-aminobutyric acid (GABA) neurotransmission was tested by iontophoretically administering bicuculline (GABA receptor antagonist) in the dentate gyrus. Methods: Urethane anesthetized rats were pretreated with VGB (50, 100 or 200 mg/kg, i.p.) or CCK-8S (8 nmol/kg, i.p.) alone or coadministered with VGB (50 mg/kg, i.p.). Dentate gyrus epileptic activity was obtained through the repetitive electr…
Furosemide interactions with brain GABAA receptors
1997
1. The loop diuretic furosemide is known to antagonize the function of gamma-aminobutyric acid type A (GABAA) receptors. The purpose of the present study was to examine the direct interaction of furosemide with the GABAA receptors by autoradiography and ligand binding studies with native rat and human receptors and with recombinant receptors composed of rat subunits. 2. Autoradiography with [35S]-t-butylbicyclophosphorothionate ([35S]-TBPS) as a ligand indicated that furosemide (0.1-1 mM) reversed the 5 microM GABA-induced inhibition of binding only in the cerebellar granule cell layer of rat brain sections. In all other regions studied, notably also in the hippocampal and thalamic areas, f…
GABAC receptors are functionally expressed in the intermediate zone and regulate radial migration in the embryonic mouse neocortex
2010
Radial neuronal migration in the cerebral cortex depends on trophic factors and the activation of different voltage- and ligand-gated channels. To examine the func- tional role of GABAC receptors in radial migration we ana- lyzed the effects of specific GABAA and GABAC receptor antagonists on the migration of BrdU-labeled neurons in vitro using organotypic neocortical slice cultures. These experi- ments revealed that the GABAA specific inhibitor bicuculline methiodide facilitated neuronal migration, while the GABAC specific inhibitor (1,2,5,6-tetrahydropyridine-4-yl) methylphos- phinic-acid (TPMPA) impeded migration. Co-application of TPMPA and bicuculline methiodide or the unspecific ionot…
Inhibition of GABA and benzodiazepine receptor binding by penicillins.
1980
Penicillins are thought to be GABA receptor antagonists. In order to determine the affinities of various penicillin derivatives for the GABA receptor, their potencies as inhibitors of specific [3H]GABA binding to rat brain membranes were investigated. All investigated penicillins inhibit specific [3H]GABA binding, with IC50 values ranging from 2 to 60 mM. The results are consistent with the assumption that penicillins are weak GABA receptor antagonists.