Dynamic exercise-induced increase in lymphocyte beta-2-adrenoceptors: Abnormality in essential hypertension and its correction by antihypertensives

Abstract

We compared the effects of acute stimulation of sympathetic activity by dynamic exercise on a bicycle on lymphocyte beta 2-adrenoceptor density and 10 mumol/L (-)-isoprenaline-evoked lymphocyte cyclic adenosine monophosphate increases in normotensive volunteers with those in patients with essential hypertension. In normotensive subjects exercise increased lymphocyte beta 2-adrenoceptors by about 100%. This effect seems to be a beta 2-dependent process, since it is prevented by propranolol (5 mg administered intravenously) and the beta 2-selective antagonist ICI 118,551 (25 mg t.i.d. orally for 2 weeks) but not by the beta 1-selective antagonist bisoprolol (2.5 mg administered intravenously). In patients with essential hypertension who have elevated lymphocyte beta 2-adrenoceptors, dynamic exercise caused only marginal beta 2-adrenoceptor changes, suggesting an impairment of the acute beta-adrenoceptor regulation. Normalization of blood pressure by antihypertensive treatment resulted in a significant fall in lymphocyte beta 2-adrenoceptors and in a restoration of exercise-induced beta 2-adrenoceptor increases. It is concluded that in essential hypertension the impairment of beta-adrenoceptor regulation is directly linked to the elevated blood pressure.