title: Isoguvacine, isonipecotic acid, muscimol and N-methyl isoguvacine on the GABA receptor in rat sympathetic ganglia.
abstract: The GABA-mimetic activities of 4 analogues muscimol, isonipecotic acid, isoguvacine and N-methyl isoguvacine have been examined at the GABA receptor in the rat isolated superior cervical ganglion. The depolarizing action of all 4 analogues could be selectively antagonized by bicuculline methochloride and isopropyl bicyclophosphate. Muscimol was the only analogue more potent than GABA (molar potency ratio = 5.08 +/- 0.707). The potency of isoguvacine was 0.23 +/- 0.026 and isonipecotic acid 0.011 +/- 0.0028. N-methyl isoguvacine was less than 0.001 GABA.
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005725:Ganglia, Autonomic / Q000187:drug effects; D007539:Isonicotinic Acids / Q000494:pharmacology; D007540:Isonipecotic Acids / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D017981:Receptors, Neurotransmitter / Q000187:drug effects* / Q000378:metabolism; D013329:Structure-Activity Relationship; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D007539:Isonicotinic Acids; D007540:Isonipecotic Acids; D017981:Receptors, Neurotransmitter; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; C015300:isoguvacine