Identificação e expressão do receptor MAS no coração em diferentes condições fisiológicas e patológicas.

Abstract

Cardiac remodelling occurs through cellular alterations in different physiological and pathological conditions which are still poorly understood. The reninangiotensin system is known to have an important role in this process. The recent identification of the Mas receptor as the principal receptor for Ang-(1-7) has attracted much attention because the Ang-(1-7) / Mas receptor axis is the principal cardioprotective and counterregulatory pathway that opposes the Ang II / receptor AT1 pathway. In recent years many studies have shown cardioprotective effects ofAng-(1-7) through Mas receptor but few studies investigated altered expression of heart Mas receptor under different pathophysiological conditions. The aim of the present work was to identify the possible alterations of Mas receptor expression in the heart of animals in three different physiological and pathological conditions: aging, physiological, and pathological hypertrophy. The experimental groups to study the effect of ageing on Mas expression were: neonatal, 21 days, 3 months,12months and 18 months. To study physiological and pathological hypertrophy, 3 month old Wistar rats were submitted to either physical training or chronic treatment with isoproterenol, and compared to untreated controls. Results demonstrated higher Mas expression in hearts of older rats, unaltered expression in hearts of trained rats with physiological cardiac hypertrophy and lower expression in rats with pathological hypertrophy after chronic treatment with isoproterenol. These results suggest an important role for Mas receptor in differentprocesses of cardiac remodelling.