Blunting of Beta-Adrenoceptor-Mediated Cardiovascular Responses and Increasing Alpha-Receptor-Mediated Vasoconstriction: An Age-Dependent Transformation of Essential Hypertension

摘要: The role of the sympathetic nervous system in cardiac, renal and peripheral vascular adrenoceptor-mediated responses was investigated patients with essential hypertension age-matched normotensive subjects. Regardless age, plasma adrenaline significantly higher hypertensive when compared This suggests a sympatho-adrenal factor hypertension. Plasma noradrenaline tended to increase age but its similarity between subjects points similar postganglionic neural activity and/or overflow into circulation. On other hand, beta-adrenoceptor-mediated tachycardia response exercise intravenous isoproterenol as well forearm vasodilator intraarterial decreased normal older age. In hypertensives this age-dependent beta-receptor-related effect tends be enhanced judged from greater reduction cardiac sensitivity blunted renin stimulation.