Specific antagonism of GABA‐mediated postsynaptic inhibition in cultured mammalian spinal cord neurons

Abstract

Mammalian spinal neurons grown in tissue culture were used to study the effects of the four convulsants—penicillin, pentylenetetrazol, picrotoxin, and bicuculline—on these neurons responses to amino acids. Bath application of all four convulsants produced paroxysmal depolarizing events in the neurons; iontophoresis of the four convulsants selectively depressed responses produced by iontophoresis of the putative inhibitory transmitter GABA, and effected this depression without altering either inhibitory responses to β-alanine or glycine, or excitation mediated by glutamate. These results support the hypothesis that the convulsant activity of these agents comes in part from selective antagonism of GABA-mediated postsynaptic inhibition.