[Mechanisms of the adaptive and trophic effects of the sympathetic nervous system on brain vessels and tissue].

Data on immediate and delayed effects of cervical sympathectomy and stimulation of cervical postganglionic sympathetic fibers on cerebral circulation, hypothalamic neurosecretion and cerebral metabolism, are presented. Acute experiments in cats revealed adaptive function of cerebral vascular sympathetic innervation during rapid changes of arterial pressure. Data on the influence of basal vascular tone on post-desympathization circulatory effects were obtained. Long-lasting consequences of sympathetic stimulation (vasoconstriction and cerebral oedema) seem to depend on the activation of vasopressin secretion. Biochemical studies in rats revealed changes of (K+-Na+) ATPase activity, degree of oxidation and phosphorylation as well as dynamics of cAMP-cGMP and prostaglandin E, F2 alpha concentration in brain tissue in different period after cervical desympathization in conditions of normal cerebral blood supply and after circulatory cerebral hypoxia. The significance of sympathetic innervation for the adaptive and compensatory brain reactions to circulatory changes and damages is discussed.