alpha(1)-adrenergic receptor subtypes in peripheral blood lymphocytes of essential hypertensives

Objective The expression of alpha (1)-adrenergic receptor subtypes in perip heral blood lymphocytes was investigated in 28 essential hypertensive patie nts as well as in the peripheral blood lymphocytes and aorta of spontaneous ly hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Methods alpha (1)-Adrenergic receptors were quantified by radioligand bindi ng assays, employing [H-3]-prazosin as the radioligand in association with compounds displaying different degrees of selectivity for alpha (1A)-, alph a (1B)- and alpha (1D)-adrenergic receptor subtypes. Results The affinity of [H-3]-prazosin binding was similar in peripheral bl ood lymphocytes of different stage essential hypertensive and normotensive subjects or of SHR and age-matched normotensive WKY rats as well as in the aortas of SHR and WKY rats. The radioligand binding assay revealed no chang e in the expression of alpha (1)-adrenergic receptors in peripheral blood l ymphocytes of essential hypertensives compared with normotensive subjects; a moderate decrease Of alpha (1B)-adrenergic receptors and an increase Of a lpha (1D)-adrenergic receptors. The relative densities of the alpha (1)-adr energic receptor subtypes were similar in the three groups of essential hyp ertensives. In peripheral blood lymphocytes and in aorta of SHR, [H-3]prazo sin binding was significantly reduced compared with normotensive WKY rats. The expression of alpha (1)-adrenergic receptor subtypes in peripheral bloo d lymphocytes of SHR was similar to that found in peripheral blood lymphocy tes of essential hypertensives. Conclusions Changes of lymphocyte alpha (1)-adrenergic receptor subtypes in essential hypertensives are similar to those observed in lymphocytes and v ascular tissues of animal models of hypertension. This suggests that assays of lymphocyte alpha (1)-adrenergic receptors may represent an indirect mar ker of their involvement in essential hypertension. (C) 2001 Lippincott Wil liams & Wilkins.