PRESYNAPTIC ACTIONS OF Β‐AMINOBUTYRIC ACID AND SOME ANTAGONISTS IN a SLICE PREPARATION OF CUNEATE NUCLEUS

Abstract

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 y-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 (+)-bi&uculline and strychnine. 4 Bemegride and leptazol both antagonized GABA, but with low potency and in a manner which was clearly not competitive.

Distinction Between the Effects of Barbiturates, Benzodiazepines and Phenytoin on Responses to Γ‐aminobutyric Acid Receptor Activation and Antagonism by Bicuculline and Picrotoxin

“…This yielded slices 0.5-0.6 mm thick (Simmonds, 1978). The caudal end of the dorsal funiculus was trimmed free of underlying tissue so that the slice could be placed in a two-compartment bath with the bulk of the slice in one compartment and the caudal end of the dorsal funiculus projecting through a greased slot from the second compartment (Hayes & Simmonds, 1978).…”

Two distinct interactions of barbiturates and chlormethiazole with the GABAA receptor complex in rat cuneate nucleus in vitro

“…Experiments were performed on slices of cuneate nucleus prepared from male Wistar rats (Tuck) as previously described (Simmonds, 1978;1980). Each slice was placed in a two-compartment bath and superfused with Krebs medium at room temperature so that depolarizations of the dorsal funiculus fibres and terminals mediated by the GABA receptor could be recorded as population responses.…”

Quantitative studies on some antagonists of N‐methyl D‐aspartate in slices of rat cerebral cortex

“…An alternative approach is to employ bath application of drugs to isolated neuronal preparations, for example, the isolated hemisected frog spinal cord (Ault et al, 1980). Such an approach has proved useful in the study of receptors for y-aminobutyric acid (GABA) in the cuneate nucleus of the rat (Simmonds, 1978).…”