Authors:A. Sharifi, S. Mohseni, S. Nekoparvar, B. Larijani, H. Fakhrzadeh and S. Oryan
High calorie intake and high weight gain is one of the worldwide health problems particularly in industrial and developed countries. The subjected individuals are at high risk for developing various disorders such as diabetes and particularly cardiovascular problems. It has been well established that life style modification plays an important role in reducing these problems, particularly weight reduction and caloric restriction (CR) as a non-pharmacological approach. This study sought to examine the possible effect of caloric restriction on nitric oxide production, ACE activity and blood pressure regulation in rat. Two groups of rats were selected as the control (C) and the CR group and a with standard and an every other day diet, respectively, for 4 weeks. At the end of study in the CR group systolic blood pressure was significantly decreased compared to controls. The serum NO
was significantly increased compared to the C group. The serum ACE activity was lower in the CR group. Therefore, it may be concluded that CR could reduce blood pressure by elevating NO production and lowering ACE activity.
The vasodilatory effect of angiotensin 1–7 (Ang 1-7) is exerted in the vascular bed via Mas receptor (MasR) gender dependently. However, the crosstalk between MasR and angiotensin II (Ang II) types 1 and 2 receptors (AT1R and AT2R) may change some actions of Ang 1-7 in renal circulation. In this study by blocking AT1R and AT2R, the role of MasR in kidney hemodynamics was described. In anaesthetized male and female Wistar rats, the effects of saline as vehicle and MasR blockade (A779) were tested on mean arterial pressure (MAP), renal perfusion pressure (RPP), renal blood flow (RBF), and renal vascular resistance (RVR) when both AT1R and AT2R were blocked by losartan and PD123319, respectively. In male rats, when AT1R and AT2R were blocked, there was a tendency for the increase in RBF/wet kidney tissue weight (RBF/KW) to be elevated by A779 as compared with the vehicle (P=0.08), and this was not the case in female rats. The impact of MasR on renal hemodynamics appears not to be sexual dimorphism either when Ang II receptors were blocked. It seems that co-blockade of all AT1R, AT2R, and MasR may alter RBF/ KW in male more than in female rats. These findings support a crosstalk between MasR and Ang II receptors in renal circulation.