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EFFECTS OF AMINO ACIDS AND CONVULSANTS ON SPONTANEOUS ACTION POTENTIALS IN CEREBELLAR CORTEX SLICES
Author(s) -
OKAMOTO K.,
QUASTEL J.H.
Publication year - 1976
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1976.tb07650.x
Subject(s) - strychnine , picrotoxin , taurine , convulsant , glycine receptor , glycine , inhibitory postsynaptic potential , chemistry , amino acid , alanine , excitatory postsynaptic potential , biochemistry , gabaa receptor , receptor , biology , endocrinology
1 Picrotoxin selectively and reversibly suppressed the inhibitory action of γ‐aminobutyric acid (GABA), but not that of glycine, taurine or β‐alanine, on the frequency of spontaneous spike discharges in guinea‐pig cerebellar slices. Strychnine reversibly suppressed the inhibitory action of glycine, taurine or β‐alanine but had no effect on that of GABA. 2 GABA, glycine, taurine and β‐alanine showed an early excitatory effect that was unaffected by picrotoxin or strychnine. 3 Studies of the dose‐response relations indicated a competition between the amino acid and the convulsant at a common receptor site. 4 Kinetic analyses of the dose‐response relations for the amino acids in the presence or absence of picrotoxin or strychnine indicated that the number of molecules of amino acid combining with the receptor site in order to produce a response (inhibition or excitation) was 3 for GABA, 2 for glycine, 3 for taurine and 4 for β‐alanine. There appeared to be no evidence that the response was due to the cooperativity between the amino acid receptor complexes. The number of molecules of convulsant that combined with the receptor site was 1 for either strychnine or Picrotoxin. 5 Mixtures of glycine with taurine or β‐alanine, in contrast to those with GABA, appeared not to give additive inhibitory effects.