Effects of chlorpromazine and diazepam on neuronal activities of the lateral vestibular nucleus in cats.

The effects of chlorpromazine and diazepam on vestibular neuronal activity were studied in gallamine immobilized cats. Chlorpromazine depressed all the P, N1 and N2-waves of field potentials in the lateral vestibular nucleus evoked by electrical stimulation of the vestibular nerve. Diazepam also reduced the amplitude of postsynaptic components (N1 and N2-waves), while the presynaptic one (P-wave) was slightly increased. Chlorpromazine suppressed the spontaneous as well as the increased vestibular neuronal firing following stimulation of the vestibular nerve. Diazepam enhanced the increased vestibular neuronal firing excited by the nerve stimulation and had no effect on the spontaneous unitary discharges.