Effects of Bemitil on Electrical Activity of the Aminergic Systems and Cerebral Cortex in Awake Cats

Abstract

Under conditions of chronic experiments on awake cats, we studied changes in the impulse activity generated by brainstem monoaminergic neurons and also in the background field electrical activity of the neocortex induced by peroral administration of 150 mg/kg bemitil. In supposedly serotonergic neurons of the n. raphe, upon the action of this agent, the frequency of spike generation underwent two-phase modifications. Five to 20 min after administration of bemitil, a decrease (insignificant) in the frequency was followed by an increase (on the 35th min, the frequency began to significantly exceed the initial values, P < 0.05). Beginning from the 5th min of the exposure, discharges of noradrenergic neurons of the locus coeruleus were unidirectionally and significantly (P < 0.05) suppressed. With parallel EEG recording, we observed changes in the spectral powers (SPs) of separate rhythms; the SPs of alpha and delta oscillations increased, while the power of the theta rhythm dropped. We compared the effects of bemitil administered in different doses (50, 100, and 150 mg/kg). Possible mechanisms underlying the effect of bemitil on the functioning of cerebral mechanisms are discussed.