[The neurochemical mechanisms of the influence of the posterior hypothalamus on the electrical activity of the forebrain hemispheres and on autonomic reactions in hens].

Effects of i.v. administration of N- and M-cholinergic blocking agents ganglerone and atropine and alpha- and beta-adrenergic blocking agents phentolamine and obsidan (propranolol) on reaction of desynchronisation of EEG and on autonomic reactions (arterial blood pressure, heart and respiratory rates) evoked by low- and high frequency stimulation of the posterior hypothalamus were studied in hens. It was shown that atropine induces a pharmacological dissociation of ascending and descending influences of the hypothalamus by blocking the desynchronizing mechanisms of the upward discharge of the hypothalamus without any apparent changes of autonomic reactions. It was found that the effects of adrenoblocking agents are diametrically opposite to that of atropine in regard to the EEG component, as well as the autonomic components of hypothalamically induced activation reaction. Peculiarities of evolutionary development of neurochemical structures of ascending and descending systems of the hypothalamus are discussed.