Effect of choline on the changes related to blood pressure induced by intermittent hemorrhage in rats

Abstract

The influence of choline given intracerebroventricularly (i.c.v.) on the changes related to blood pressure induced by intermittant hemorrhage and the mechanisms contributing te this influence were examined. A catheter was inserted into the left carotid artery of female Wister albino rate and another cannula was placed into their right lateral cerebral ventricle for i.c.v. injections. Five minutes after the i.c.v. injections were administered, blood (0.5 ml/100 g body weight) was taken five times at five minutes intervals. The influence of each hemorrhage on blood pressure was examined by measuring the blood pressure five minutes after each blood sample was teken. Three different doses of choline (50, 100, 150 μg) given i.c.v. attenuated the fall in blood pressure caused by intermittent hemorrhage. Nicotinic receptor antagonist mecamylamine and muscarinic receptor antagonist atropine blocked the influence of choline on blood pressure. When the specific antegonist was given intraaretreally to block vasopressin as a pressor, it prevented the influence of choline on bloodpressure. Our findings represent the fact that choline given intracerebroventricularly attenuates the fall in the blood pressure caused by intermittent hemorrhage. The influence of i.c.v. injection of choline suggests that this effect must be mediated via the central nicotinic and muscarinic receptors. The vasopressinergic system also contributes to these influences.