EFFECTS OF CENTRAL DEPRESSANTS ON THE CORTICAL AUDITORY RESPONSES IN THE UNRESTRAINED CATS

Abstract

The effects of pentobarbital sodium, [alpha]-chloralose, chlorpromazine hydrochloride, urethane and ethyl alcohol on the cortical evoked responses caused by clicks were observed in the unrestrained cats with chronically implanted electrodes. The cortical click responses were larger in the resting and drowsy states than in the alert state, while they were smaller in the sleep state, including the paradoxial sleep, than in the alert one. Intravenous injection of the small doses of pento-barbital sodium, chloralose and chlorpromazine produced a marked increase in amplitude of the cortical click responses. On the other hand, the administration of urethane and ethyl alcohol resulted in decrease of their amplitude. The effects of the central depressants on the cortical click responses in the unrestrained cats agreed well with those in the acute restrained animals.