The effect of Angiotensin II Injection in the Suprachiasmatic Nucleus on Cardiovascular Regulation in Male Rat

High blood pressure is known as the third cause of death in the world. millions of people are affected by this disease. The renin-angiotensin system plays a role in causing this disease. AngiotensinII receptor blockers (AT1) are effective in reducing blood pressure. AngiotensinII expression has been observed in the suprachiasmatic nuclei. The aim of this study is to investigate the effect of angiotensinII injection in the suprachiasmatic nucleus on the cardiovascular function of rats.

24 male Wistar rats were divided into 3 groups. 1- control, 2- angiotensin II, 3- angiotensinII + losartan. Group1: normal saline with a dose of 100ml, group2: angiotensinII with a dose of 100μm, and group3: angiotensin with a dose of 100μm, and after 30minutes, losartan with a dose of 100μm, and after 2minutes, angiotensin with a dose of 100μm, microinjection into the suprachiasmatic nucleus and blood pressure and heart rate was recorded.

There was no significant difference between mean arterial pressure and heart rate before and after saline injection.(P>0.05), in the angiotensin group, ∆MAP and HR∆ compared to before the injection of this dose of angiotensin(P<0.001 and P<0.05), and compared to the control group(P<0.001 and P<0.01), It increased significantly. In the losartan group, microinjection of losartan before the second injection of angiotensinII caused a significant decrease in ∆MAP compared to the first injection of angiotensinII (P<0.001), but it was not significant in HR∆.

Microinjection of angiotensinII in the suprachiasmatic nucleus increased blood pressure and heart rate through binding to AT1.