Suppressing effects on electrocortical activity of gamma-aminobutyric acid in cats.

Abstract

The effects of γ-aminobutyric acid (GAB) on the cortical activity wereinvestigated in the cat anaesthetized with Nembutal by applying the substancetopically on the cortical surface in a high concentration.1. GAB suppressed both surface negative and positive components of sensoryevoked potentials, dendritic potentials and spontaneous spindle bursts. Cor-responding with the decrease in amplitude of the surface positive componentsof the evoked potentials, a recording with a microelectrode disclosed that thenegative response at the depths of the cortex was suppressed.2. The muscular movements induced by electrical stimulation of the motorcortex suffered no remarkable change even when cortical electrical activities were completely suppressed by GAB applied to the site of electrostimulation.3. The muscular responses induced by topical administration of strychnineto the motor cortex were abolished by GAB when negative components of thestrychnine spikes were suppressed.