effect of apelin on normal and diabetic cardiovascular system

The aim of this study this study was designed to detect possible effects of apelin on cardiovascular system in both normal and diabetic state, with a trial to clarify possible involved mechanisms.This study was conducted on healthy adult male albino rats; the animals were divided into 3 main groups:Group I: To study the acute effect of apelin-13injection (10 nmol\ kg) on normal cardiovascular system.Group II: To study the acute effect of apelin-13 injection (10 nmol\ kg) on the cardiovascular system of strptozotocin -induced type 1 diabetic non treated rats.Group III: To study the acute effect of apelin-13 injection (10 nmol\ kg) on the cardiovascular system of strptozotocin -induced type 1 diabetic rats treated with insulin.Our results showed that acute apelin-13 administration in vivo caused NO-mediated decrease in mean arterial blood pressure, which was more significant in diabetic rats in comparison with normal and insulin treated rats.In addition, apelin-13 injection antagonized the hypertensive action of Ang II which was less significant in the diabetic group, and augmented the hypotensive effect of acetylcholine which was more significant in the diabetic rats in comparison with that of control and insulin treated groups.Moreover, apelin-13 exerted both positive inotropic and lusiotropic effects in vivo which was more significant in diabetic rats in comparison with that of both normal and insulin treated rats. Our results also suggested that this response to apelin involved activation of Na+- Ca+2 exchange channels (NCX).Since different mechanisms are responsible for the diabetic vasculopathy and cardiomyopathy and response rate to treatments is far from homogenous and ideal, the search for additional therapeutic agents continues. Therefore, the use of apelin may be investigated as a potential therapeutic target for these pathologies.