Effect of barbiturates on release endogenous amino acids from rat cortex slices.

The potassium-stimulated, calcium-dependent release of endogenous GABA and glutamic acid was suppressed by pentobarbital. The ouabain and veratridine-stimulated fluxes of the amino acids, calcium-independent processes, were not suppressed by pentobarbital. Release of GABA and glutamic acid was not suppressed by pentobarbital in the presence of the calcium ionophore A23187. Of eight barbiturates studied at equimolar concentrations six were found to inhibit GABA release. Thiopental was the most potent, and phenobarbital and secobarbital were inactive.