Mechanism of histamine-induced calcium efflux from cultured bovine adrenal chromaffin cells: possible involvement of an Na+Ca2+ exchange mechanism

Abstract The effect of stimulation of the histamine receptor on Ca 2+ mobilization in cultured bovine adrenal chromaffin cells was examined. Histamine (10 −5 M) increased the intracellular free Ca 2+ ([Ca 2+ ] i ) to a peak in the presence or absence of extracellular Ca 2+ , followed by decrease with time. Histamine (10 −8 –10 −5 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 specific histamine H 1 receptor antagonist mepyramine. The increase in histamine-stimulated 45 Ca 2+ efflux was inhibited by deprivation of extracellular Na + and by the Na + Ca 2+ exchange inhibitor amiloride. In addition, histamine stimulated 22 Na + influx into the cells, and this action was inhibited by amiloride. These results suggest that stimulation of the histamine H 1 receptor regulates Na + Ca 2+ exchange in cultured bovine adrenal chromaffin cells.