Stimulatory effect of angiotensin II on calcium efflux from cultured bovine adrenal chromaffin cells

Abstract The effect of angiotensin II on Ca 2+ mobilization in cultured bovine adrenal chromaffin cells was examined. Angiotensin II (10 −7 M) increased the intracellular free Ca 2+ level ([Ca 2+ ] i ) to a peak in the presence or absence of extracellular Ca 2+ , followed by decrease with time. Angiotensin II (10 −9 − 10 −6 M) also stimulated 45 Ca 2+ efflux from cultured bovine adrenal chromaffin cells in a concentration-dependent manner. Its stimulatory effect on 45 Ca 2+ efflux was inhibited by the angiotensin II antagonist [Sar 1 , Ile 8 ]-angiotensin II or [Sar 1 , Val 5 , Ala 8 ]-angiotensin II. The increase in angiotensin II-stimulated 45 Ca 2+ efflux was dependent on the extracellular Na + concentration. Angiotensin II also increased 22 Na + influx into the cells. These results indicate that stimulation of the angiotensin II receptor induces extracellular Na + -dependent Ca 2+ efflux from cultured bovine adrenal chromaffin cells, probably by acceleration of Na + /Ca 2+ exchange.