Comparative Study of Leptin and Phentolamine Effects on Cardiovascular System

Khaled Muhsen Hasan

Background: Various lines of evidence suggest that leptin participates not only in negative feedback control of body adiposity but also in cardiovascular and sympathetic regulations. The aim of this research is to study the acute effects of leptin on cardiovascular system. Rabbits were used as an experimental animal. Materials and method: These experimental animals were divided into two groups: first group consists of 15 rabbits, given intravenous injection of leptin. Second group consists also of 15 rabbits, injected by phentolamine as α-adrenergic blocker before given them leptin. Heart rate and mean arterial blood pressure were recorded by using Fukuda Denshi Apparatus. Results: In group one, mean arterial blood pressure, and heart rate have been significantly increased after intravenous injection of leptin (p<0.0001). In the second group which was injected by phentolamine, leptin did not cause significant increase in arterial blood pressure (P>0.05), but heart rate increased significantly (p>0.001). Conclusion: These results suggest that intravenous injection of leptin causes increases in arterial blood pressure and heart rate in anesthetic rabbits, and these effects could be opposed by α-adrenergic blockade. This may be partially explained by the effect of leptin on the cardiovascular system could be mediated by sympathetic pathway