INTERRELATIONSHIP BETWEEN ANGIOTENSIN II AND THE SYMPATHETIC NERVOUS SYSTEM

¹ Department of Pharmacology, University of Pittsburgh School of Pharmacy, Pittsburgh, Pennsylvania

Angiotensin II (4 µg), when administered into the perfused lateral ventricle of anesthetized cats, exerted marked pressor effects which appeared to be due to activation of central nervous system structures. The data suggested that the pressor response was sympathetic in nature, involving alpha and beta adrenergic receptors and possibly adrenomedullary secretory cells. The origin of the activity did not appear to be hypothalamic, as direct injection of the peptide into the posterior hypothalamus failed to produce pressor responses. Blockade of the pressor mechanism by cerveau isolé section indicated that suprapontine structures were involved, and the failure to obtain central pressor activity by confinement of the perfusion system to the lateral and third ventricles suggested that the activity was of midbrain origin, although the possibility of bulbar afferent mechanisms cannot be excluded.