Ca2+ channels of the L-type in peripheral blood lymphocytes of essential hypertensives

Ca2+ channels of the L-type were assayed in human peripheral blood lymphocy tes of normotensive control subjects and of essential hypertensives using r adioligand binding assay techniques. The dihydropyridine Ca2+ channel block er [H-3](+)-PN 200-110 [isopropyl1-4-(2,1,3-benzoxadiazol-4-yl)1,4-dihydro- 5-methoxycarbonyl-2,6-dimethyl-3-pyridine carboxylate] was used as a ligand . [H-3](+)-PN 200 110 was bound specifically to human peripheral blood lymp hocytes in a manner consistent with the labeling of Ca2+ channels of the L- type. No significant differences in the dissociation constant (K-d), in the maximum density of binding sites (B-max) or in the pharmacological profile of [H-3](+)-PN 200 110 binding were found between normotensive subjects an d different degree essential hypertensives. Analysis of the intralymphocyti c free Ca2+ concentration did not reveal differences between normotensive s ubjects and essential hypertensives. Although hypertension is associated wi th altered membrane handling of Ca2+, no changes in the expression of perip heral blood lymphocyte Ca2+ channels of the L-type or in intralymphocytic C a2+ concentrations were found in essential hypertensives. Human peripheral blood lymphocytes therefore cannot represent a peripheral marker of altered Ca2+ handling in hypertension. (C) 1999 American Journal of Hypertension, Ltd.