Gamma-hydroxybutyric acid decreases thalamic sensory excitatory postsynaptic potentials by an action on presynaptic GABAB receptors.
The effect of gamma-hydroxybutyric acid (GHB) on the excitatory postsynaptic potential (EPSP) evoked in thalamocortical neurones of the rat dorsal lateral geniculate nucleus and ventrobasal thalamus was investigated in vitro. GHB (0.1-5 mM) dose-dependently and reversibly decreased (36-78%) the amplitude of the sensory EPSP. This effect of GHB was blocked by the GABAB receptor antagonist CGP 35348 (1 mM). NCS 382 (1-3 mM), a putative GHB receptor antagonist, did not antagonise but weakly potentiated both the GHB- and baclofen-mediated decrease of the EPSP amplitude.
Physiology Unit, School of Molecular and Medical Biosciences, University of Wales Cardiff, UK.
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D000759:Adjuvants, Anesthesia / Q000494:pharmacology*; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D001418:Baclofen / Q000494:pharmacology; D001567:Benzocycloheptenes / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058786:GABA-B Receptor Agonists; D005829:Geniculate Bodies / Q000166:cytology*; D008297:Male; D009475:Neurons, Afferent / Q000737:chemistry / Q000502:physiology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D017729:Presynaptic Terminals / Q000737:chemistry / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D018080:Receptors, GABA-B / Q000502:physiology; D012978:Sodium Oxybate / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
D000759:Adjuvants, Anesthesia; D000927:Anticonvulsants; D001567:Benzocycloheptenes; D018755:GABA Agonists; D018756:GABA Antagonists; D058786:GABA-B Receptor Agonists; D009943:Organophosphorus Compounds; D018080:Receptors, GABA-B; C066471:NCS 382; D012978:Sodium Oxybate; C066430:CGP 35348; D001418:Baclofen; D001640:Bicuculline