Mode of action of chlorpromazine on unit discharges from nuclear structures in the brainstem of cats.

Electrophysiological studies (1-4) have shown that chlorpromazine acts on the several subcortical structures such as the brainstem reticular formation, hypothalamus and limbic system but does not appear to have significant effects on the cerebral cortex and thalamic relay nuclei. A reduction of the spontaneous unit activity by the drug has been reported in the reticular formation by Bradley (5) and Adey et al. (6), in the globus pallidus by Adey and Dunlop (7) and in the lateral hypothalamus by Zukauskas and Machine (8). However, information about effects of chlorpromazine on single neurons in the nuclear structures of the brainstem is still insufficient. We have studied the effects of morphine, aminopyrine and metoclopramide on the unit activities of single neurons in the subcortical areas (9-12), and have investigated the possible sites of action of these centrally affecting agents. The present experiment is an attempt to elucidate the mode of action of chlorpro mazine upon the unit discharges in the Nucleus tractus solitarii, Nucleus vestibularis lateralis and Nucleus sensorius superior n. trigemini on the encephale isole preparations of cats.