Mechanical stress-induced Ca21 entry and Cl2 current in cultured human aortic endothelial cells

Nakao, Miki, Kyoichi Ono, Susumu Fujisawa, and Toshihiko Iijima. Mechanical stress-induced Ca21 entry and Cl2 current in cultured human aortic endothelial cells. Am. J. Physiol. 276 (Cell Physiol. 45): C238–C249, 1999.—A fluid stream through a microtube was applied to cultured human aortic endothelial cells to investigate the endothelial responses of both the ionic currents and intracellular Ca21 concentration ([Ca]i) to mechanical stimulation. The fluid stream induced an increase in [Ca]i that was dependent on both the flow rate and the extracellular Ca21 concentration. Gd31 and niflumic acid inhibited the fluid stream-induced increase in [Ca]i, whereas Ba21 and tetraethylammonium ion exhibited no effect. The fluid stream-induced [Ca]i increase was accompanied by the activation of an inward current at 252.8 mV. The reversal potential of the fluid stream-induced current shifted to positive potentials when the external Cl2 concentration was reduced but was not affected by variation of the external Na1 concentration. During the exposure to the fluid stream, [Ca]i was voltage dependent, i.e., depolarization decreased [Ca]i. We therefore conclude that the fluid stream-induced current is largely carried by Cl2 and that the Cl2 current may thus play a role in modulating the Ca21 influx by altering the membrane potential of endothelial cells.