Involvement of protein kinase C in the regulation of Na+/Ca2+ exchanger in bovine adrenal chromaffin cells.

1. The Na(+)/Ca(2+) exchanger (NCX) exchanges Na+ and Ca(2+) bidirectionally through the forward mode (Ca(2+) extrusion) or the reverse mode (Ca(2+) influx). The present study was undertaken to clarify the role of protein kinase C (PKC) in the regulation of NCX in bovine adrenal chromaffin cells.

Inhibition by SEA0400, a selective inhibitor of Na+/Ca2+ exchanger, of Na+ -dependent Ca2+ uptake and catecholamine release in bovine adrenal chromaffin cells.

The effects of SEA0400, a selective inhibitor of the Na(+)/Ca(2+) exchanger (NCX), on Na(+)-dependent Ca(2+) uptake and catecholamine (CA) release were examined in bovine adrenal chromaffin cells that were loaded with Na(+) by treatment with ouabain and veratridine. SEA0400 inhibited Na(+)-dependent (45)Ca(2+) uptake and CA release, with the IC(50) values of 40 and 100 nM, respectively. The IC(50) values of another NCX inhibitor KB-R7943 were 1.