Datsenko V. Role of the system of nitric oxide in realization of cardiogenic and sinocarotid reflexes

Dissertation is devoted to the questions of NO-participation of nitric oxide in realization of cardiogenic and sinocarotid reflectory reactions at different species of animals. In the experiments on the dogs, was established that intracoronary injection of veratrin, adrenalin or brief sharp myocardial ischemia cause development of cardiogenic depressor reflexes with the decrease of systemic arterial pressure, resistance of coronary and limb vessels. Electrophysiological study showed that the afferent branch of these reflexes are cardiac fibres of vagus nerve and efferent - sympathetic fibres which innervate the heart and vessels, e. g. they are centrally linked and realized as vago-sympathetic. Systemic inhibition of NO synthesis by N?-nitro-L-arginine (L-NNA 30 mg/kg) considerably diminishes the depressory reactions by stimulation of cardiac receptors in dogs, and almost does not alter and sometimes even strengthens cardiogenic depressor reflexes on injection of veratrin in rats. Reduction of such reactions in rats is registered only at use of selective neuronal inhibitor NOS - 7-NI. Both in dogs, and in rats the systemic inhibition of NO synthesis slightly affect the depressor and pressor reflex reactions from carotid sinus baroreceptors. Thus, the NO-system has a considerably greater influence on the development of cardiogenic reflexes. The specific differences of distribution of NO-generating neurons are set in the cardiovascular centers of medulla oblongata in dogs and rats by gistochemical studies.