Presynaptic actions of gamma-aminobutyric acid and some antagonists in a slice preparation of cuneate nucleus.
1 A slice preparation of the rat cuneate nucleus is described which is suitable for electrophysiological studies on the presynaptic action of drugs. 2. Superfusion of a slice with gamma-aminobutyric acid (GABA) depolarized the afferent nerves in a concentration-related manner. The responses were Cl-dependent. Depolarizations to high concentrations of GABA often faded. Glycine and L-glutamate had little effect. 3 (+)-Bicuculline antagonized GABA in an apparently competitive manner (pA2 = 5.35) at low response levels. Strychnine was 10 times less potent. Responses to high concentrations of GABA were sometimes potentiated by (+)-bicuculline and strychnine. 4 Bemegride and leptazol both antagonized GABA, but with low potency and in a manner which was clearly not competitive.
D000613:Aminobutyrates / Q000494:pharmacology*; D000818:Animals; D001534:Bemegride / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D004594:Electrophysiology; D018756:GABA Antagonists; D005971:Glutamates / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects*; D009467:Neuromuscular Depolarizing Agents; D010433:Pentylenetetrazole / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D013331:Strychnine / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D000613:Aminobutyrates; D018756:GABA Antagonists; D005971:Glutamates; D009467:Neuromuscular Depolarizing Agents; D005680:gamma-Aminobutyric Acid; D001534:Bemegride; D013331:Strychnine; D011188:Potassium; D005998:Glycine; D010433:Pentylenetetrazole; D001640:Bicuculline