The study of exercise treatment for cardiovascular diseases

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The effects of chronic physical exercise (ET) on the sensitivity of thoracic aorta to norepinephrine and on adipocyte lipolysis were investigated in spontaneously hypertensive rats (SHR). After ET, the attenuated sensitivity of aorta to norepinephrine was observed in SHR rats as well as in normotensive rats. This attenuated sensitivity of aorta to norepinephrine after ET was still evident in endothelium-denuded aorta, but to a lesser extent than in endothelium-intact aorta. No significant difference in 60 mM KC1-induced tension between control and trained SHR rats was observed with or without endothelium after ET.The results suggest that levels of endothelium-dependent releasing factor may increase in response to norepinephrine after ET in SHR rats as well as in normotensive rats. In the separate experiments, adipocyte lipolysis was investigated in SHR rats after ET.Adipocyte lipolysis stimulated by various agonists, such as isoproterenol, dobutamine, salbutamol, BRL37344 and dibutyryl cyclic AMP, was blunted in non-trained SHR rats compared with normotensive rats. However, ET significantly increased adipocyte lipolysis stimulated by each agonist, although the maximal responses were less in SHR rats than in normotensive exercise-trained rats. Thus, ET significantly alter the responses of aorta to norepinephrine and those of adipocyte lipolysis to various agonists in SHR rats.