Cardiovascular effects of intracerebro-ventricular bradykinin and melittin in the rat

Abstract

Abstract The cardiovascular effects of intracerebroventricular (i.c.v.) bradykinin and melittin were investigated in the anaesthetized rat. Bradykinin, 30 μg, increased mean arterial pressure by 15 mmHg and this was the result of an increase in peripheral resistance; heart rate and cardiac output were unchanged. Tissue blood flow was lower in the skin and spleen in the animals given bradykinin than the controls. Significant increases in tissue vascular resistance occurred in the skin and several organs of the splanchnic region, the spleen, stomach, large intestine and the pancreas/mesentery. Melittin infusion gave a biphasic response in systemic blood pressure in which a depressor response was followed by a pressor phase; the pressor stage was accompanied by an increase in heart rate. Since melittin is a stimulant of membrane bound kallikrein, the results lend limited support to the hypothesis that there is a kallikrein-kinin system endogenous to the central nervous system which is involved in cardiovascular regulation.