The renin-angiotensin system, cardiac hypertrophy, and salt-sensitive hypertension in Dahl rats.

Abstract

We evaluated the activity of tissue (i.e., brain and cardiac) versus circulatory renin angiotensin systems (RASs) during (1) the development of high salt-induced hypertension and cardiac hypertrophy; and (2) the prevention of salt-sensitive hypertension by chronic blockade of brain "ouabain". For protocol I, ACE mRNA and activity in the hypothalamus and pons, as well as in the left ventricle (LV) and right ventricle (RV); angiotensin I and II (Ang I, II) in the hypothalamus and pons, as well as in the ventricle and plasma, and plasma renin activity (PRA) were assessed in Dahl salt-sensitive (Dahl S) and salt-resistant (Dahl R) rats on high (1370 mumol/g) or regular salt (120 mumol/g) diet for 2 or 4--5 weeks. For protocol II, ACE mRNA and activity in the hypothalamus and pons, and in the LV and RV were measured in Dahl S rats on high salt with either icv Fab fragments binding brain "ouabain" or gamma-globulins as control, or, regular salt with icv gamma-globulins; and in Dahl R rats on high or regular salt diet for 4--5 weeks. (Abstract shortened by UMI.)