[Participation of the hypothalamus in regulation of the pituitary-adrenal system in accordance with the feedback principle].

The multiunit activity and activity of pituitary-adrenocortical system were studied in chronic experiments on intact unrestrained rabbits injected with cortisol (1 mg/kg, i.v.). The pituitary-adrenocortical system was inhibited by cortisol (the level of corticosterone decreased) as well as the majority of the neuronal pools in the medial and lateral hypothalamus. The anterior hypothalamic neurons mostly responded to cortisol by a rise in firing rate. The changes observed suggest the existence of some electrophysiological correlates of the corticosteroid feedback mechanisms.