Brain angiotensin type 1 receptor expression and function in the Zucker obese rat

The Zucker obese rat is a model with predisposition for hypertension. There is evidence that angiotensin II (ANG II) may play a role in the maintenance of this hypertension. However, the potential role of brain ANG II in this regard has been largely unexplored. The aim of the present study was to compare the pressor response produced by i. c.v. injection of ANG II in Zucker obese and lean rats, and to determine if functional differences could be correlated to changes in brain AT1 receptor protein and/or mRNA expression. The Zucker obese rat had a significantly greater increase in blood pressure after i.c.v. injection of ANG II compared to the lean rat. AT1 receptor protein expression was greater in the brainstem, but not the hypothalamus, of the obese rat. These data raise the possibility that increased central responsiveness to ANG II may play a role in the predisposition of the Zucker obese rat to hypertension.