Cytosolic calcium changes induced by angiotensin II in human peripheral blood mononuclear cells are mediated via angiotensin II subtype 1 receptors

P Lijnen, R Fagard, V Petrov - Journal of hypertension, 1997 - journals.lww.com
P Lijnen, R Fagard, V Petrov
Journal of hypertension, 1997journals.lww.com
Objective To determine the effects of angiotensin II (AII)(1–8) on cytosolic free calcium
concentrations in the absence and in the presence of the selective angiotensin subtype 1
(AT 1) receptor antagonist losartan and of the selective angiotensin subtype 2-receptor
antagonist P-186 in human peripheral blood mononuclear cells (PBMC). We also assessed
the effect of the AII analogues AII (2–8), AII (3–8) and AII (4–8) on the cytosolic free-calcium
concentration in human PBMC. Methods The cytosolic free-calcium concentration was …
Abstract
Objective
To determine the effects of angiotensin II (AII)(1–8) on cytosolic free calcium concentrations in the absence and in the presence of the selective angiotensin subtype 1 (AT 1) receptor antagonist losartan and of the selective angiotensin subtype 2-receptor antagonist P-186 in human peripheral blood mononuclear cells (PBMC). We also assessed the effect of the AII analogues AII (2–8), AII (3–8) and AII (4–8) on the cytosolic free-calcium concentration in human PBMC.
Methods
The cytosolic free-calcium concentration was assayed in human peripheral blood mononuclear cells by measuring the fluorescence of fura-2 entrapped by these cells.
Results
Administration of AII caused a concentration-dependent increase in the cytosolic free-calcium concentration in human peripheral blood mononuclear cells with a half-maximal increase at 5× 10− 8 mol/l. Also administration of the heptapeptide AII (2–8) increased the intracellular free-calcium concentration in human PBMC, whereas AII (3–8) and AII (4–8) had no effect. The AII (1–8)-induced rise in cytosolic free-calcium concentration was blocked completely by losartan but not by P-186.
Conclusion
Our data demonstrate that the effects of AII on the cytosolic free-calcium concentration in human PBMC are AT 1 receptor-mediated since they were abolished by the specific AII AT 1 receptor antagonist losartan but not by the specific angiotensin subtype 2 receptor antagonist P-186.
Lippincott Williams & Wilkins