ObjectiveThe expression of α1-adrenergic receptor subtypes in peripheral blood lymphocytes was investigated in 28 essential hypertensive patients as well as in the peripheral blood lymphocytes and aorta of spontaneously hypertensive rats (SHR) and normotensive Wistar–Kyoto (WKY) rats.Methodsα1-Adrenergic receptors were quantified by radioligand binding assays, employing [3H]-prazosin as the radioligand in association with compounds displaying different degrees of selectivity for α1A-, α1B- and α1D-adrenergic receptor subtypes.ResultsThe affinity of [3H]-prazosin binding was similar in peripheral blood 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 change in the expression of α1-adrenergic receptors in peripheral blood lymphocytes of essential hypertensives compared with normotensive subjects; a moderate decrease of α1B-adrenergic receptors and an increase of α1D-adrenergic receptors. The relative densities of the α1-adrenergic receptor subtypes were similar in the three groups of essential hypertensives. In peripheral blood lymphocytes and in aorta of SHR, [3H]-prazosin binding was significantly reduced compared with normotensive WKY rats. The expression of α1-adrenergic receptor subtypes in peripheral blood lymphocytes of SHR was similar to that found in peripheral blood lymphocytes of essential hypertensives.ConclusionsChanges of lymphocyte α1-adrenergic receptor subtypes in essential hypertensives are similar to those observed in lymphocytes and vascular tissues of animal models of hypertension. This suggests that assays of lymphocyte α1-adrenergic receptors may represent an indirect marker of their involvement in essential hypertension.