Reduction of gamma-aminobutyric acid level in the cat cerebral cortex by afferent electrical stimulation

—Electrical stimulation for 30 s of one brachial plexus in cat (afferent electrical stimulation = AES) produced a 20% decrease in GABA level of the stimulated (contralateral) cerebral cortex as compared to the non‐stimulated (ipsilateral) cortex in the same animal. This change in GABA was reversed within a few seconds after cessation of stimulation. Inhibition of GABA catabolism by aminooxyacetic acid elevated considerably the cortical level of GABA but failed to prevent lowering GABA by AES. When AES was performed in preconvulsive condition induced by administration of picrotoxin, the decrease in GABA was negligible, while similar treatment with pentylenetetrazol had no influence on the decrease in GABA produced by AES. The observed lowering cortical GABA by AES is interpreted as being associated with some mechanism of the inhibitory transmitter inactivation.