Received November 6, 2007
Revised January 2, 2008
Accepted after revision February 7, 2008

¹ Federal University of Minas Gerais
² University of Florida

^* To whom correspondence should be addressed. E-mail: robsonsant{at}gmail.com.

	Abstract

In the current study we investigated the effects of physical training on plasma and cardiac Angiotensin-(1-7) [Ang-(1-7)] levels. In addition, possible changes in Ang-(1-7) receptor Mas expression in the heart were also evaluated. Normotensive Wistar rats and spontaneously hypertensive rats (SHR) were subjected to 8-week period of 5% overload swimming training. Blood pressure was determined by a tail-cuff system. Heart and left ventricle weights and cardiomyocyte diameter were analyzed to evaluate cardiac hypertrophy. Radioimmunoassay was used to measure angiotensin levels. Expression of Mas was determined by semi-quantitative polymerase chain reaction, immunofluorescence, and western blotting. Physical training induced cardiac hypertrophy in Wistar rats and SHR. A significant decrease of plasma Angiotensin II (Ang II) levels in both strains was also observed. Strikingly, trained SHR, but not trained Wistar rats, showed a 2-fold increase in left ventricle Ang-(1-7) levels. No significant changes were observed in plasma Ang-(1-7) and left ventricle Ang II concentration in both strains. Furthermore, Mas mRNA and protein expression in left ventricle were substantially increased in trained SHR. The physical training protocol used did not change blood pressure in both strains. These results suggest that the beneficial effects induced by swimming training in hypertensive rats might include an augmentation of Ang-(1-7) and its receptor in the heart.

Key Words: Angiotensin, Exercise, Heart