Effect of Psychotropic Drugs on Caudate Spindle in Cats1

Open Access
Publisher Website
Google Scholar
Abstract
To ascertain whether neuroleptics act on the caudate nucleus itself, the effects of these compounds as well as other centrally acting drugs were examined in relation to caudate spindle and EEG [electroencephalogram] arousal responses (sciatic nerve stimulation) in gallamine-immobilized cats. Haloperidol and chlorpromazine enhanced the caudate spindle at a dose which had no effect on the EEG arousal response. Clozapine and a higher dose of chlorpromazine enhanced the caudate spindle, but depressed the arousal response. High frequency stimulation of the sciatic nerve suppressed the caudate spindle. Pentobarbital, biperiden and diazepam, while depressing the arousal response, caused an enhancement of the caudate spindle. Imipramine at a low dose had no effect on either response, whereas at a high dose this drug enhanced the caudate spindle with concomitant depression of the arousal response. The enhancing action on the caudate spindle induced by haloperidol and a low dose of chlorpromazine is due to an increase in susceptibility of the caudate nucleus itself. Depression of the activating system possibly is involved in an appearance of the caudate spindle.