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Effect of estrogenic replacement on the cardiovascular autonomic and morphometric adaptations resulting from resistive and aerobic physical exercise in submitted rats to the chronic blockade of nitric oxide sinthase


The study aim is to asses in ovariectomized rats, with or without hormonal replacement, the cardiovascular morphometric and autonomic adaptations and cardiac morphometric induced by resistive and aerobic training, as well as, to investigate the nitric oxide (NO) role on these adaptations. Wistar rats will be distributed in six great groups; group submitted to bilateral ovariectomy (OVT group), group submitted to bilateral ovariectomy and hormonal replacement with estradiol (OVT-R group), sham-operated group (SHAM group), ovariectomized group treated with NG-nitro-L-arginine methyl ester (L-NAME), a NO synthase inhibitor (OVT L-NAME group), ovariectomized group treated with L-NAME and estradiol replacement (OVT-R L-NAME group) and sham-operated group treated with L-NAME (SHAM L-NAME group). Each group will be divided in three sub-groups, sedentary, aerobic exercise trained and resistive exercise trained during 10 weeks. All the animals will be submitted to experimental procedure to heart rate and arterial pressure register to cardiovascular autonomic function assessment. This assessment will be performed through three different approaches: baroreceptor reflex sensibility assessment by means of nitroprusside sodium and phenylephrine administration, sympathetic/vagal tonus pharmacological investigation, analysis of arterial pressure and heart rate variability through spectral analysis. Besides, it will also be performed the cardiac morphometric analysis in all groups, with aiming to perform and compare the cardiac tissue adaptations and the new capillary vessel expression (angiogenesis) promoted by resistive and aerobic training and, to investigate the relation of this adaptations with the beta-estradiol and nitric oxide. (AU)