Effect of aerobic exercise training on the autonomic control of heart rate and arterial pressure in rats submitted to L-NAME hypertension model

Abstract

The evolution of hypertension model induced by nitric oxide synthase inhibition with NG-nitro-L-arginine-methyl-ester (L-NAME) is characterized by vascular capacity reduction of relaxation. Additionally, it has been observed that this hypertension model presents a decreased baroreflex sensitivity associated with an cardiocirculatory sympathetic overactivity. On the other hand, the aerobic exercise training presents as consequence the reduction of sympathetic cardiocirculatory activity. Therefore, the objective of the present study is to evaluate in rats if the aerobic exercise training with aerobic exercise per 12 weeks is capable to prevent or to attenuate the autonomic alterations observed in this hypertension model. The animals will be divided in four distinct groups; normotensive group, hipertensive group by L-NAME administration, trained-group by means in motorized treadmill during 12 weeks and trained-group submitted to L-NAME administration. All animals will be submitted to the experimental procedure for arterial pressure and heart rate recording for evaluation of cardiovascular autonomic function. This evaluation will be carried through by three different protocols: pharmacological investigation of sympathetic/vagal/ tonus; evaluation of baroreflex sensitivity by means of the administration of phenylephrine and sodium nitroprusside; analysis of the heart rate and arterial pressure variability by means of the spectral analysis. (AU)