Elevated adrenaline and increased alpha-adrenoceptor-mediated vasoconstriction in essential hypertension.
In patients with essential hypertension, plasma adrenaline, regardless of age, was consistently higher than in normotensive controls; adrenaline correlated with heart rate and the vasodilator response in the forearm circulation produced by postjunctional alpha 1-adrenoceptor blockade with prazosin. This dilator response to prazosin was greater in hypertensive patients. Together, this suggests elevated sympathetic activity and enforced vasoconstriction via postjunctional alpha 1-adrenoceptors in essential hypertension. beta-Adrenoceptor-mediated cardiovascular responses decrease with age and even more with high blood pressure, which contributes to unopposed alpha-adrenoceptor-mediated vasoconstriction. This could explain the transition from an early high cardiac output into a later high peripheral resistance form of hypertension.
D000222:Adaptation, Physiological; D000375:Aging; D004837:Epinephrine / Q000097:blood*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000503:physiopathology*; D011941:Receptors, Adrenergic / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology; D014661:Vasoconstriction
D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D004837:Epinephrine