Mechanical stress-induced Ca2+ entry and Cl- current in cultured human aortic endothelial cells.
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 Ca2+ concentration ([Ca2+]i) to mechanical stimulation. The fluid stream induced an increase in [Ca2+]i that was dependent on both the flow rate and the extracellular Ca2+ concentration. Gd3+ and niflumic acid inhibited the fluid stream-induced increase in [Ca2+]i, whereas Ba2+ and tetraethylammonium ion exhibited no effect. The fluid stream-induced [Ca2+]i increase was accompanied by the activation of an inward current at -52.8 mV. The reversal potential of the fluid stream-induced current shifted to positive potentials when the external Cl- concentration was reduced but was not affected by variation of the external Na+ concentration. During the exposure to the fluid stream, [Ca2+]i was voltage dependent, i.e., depolarization decreased [Ca2+]i. We therefore conclude that the fluid stream-induced current is largely carried by Cl- and that the Cl- current may thus play a role in modulating the Ca2+ influx by altering the membrane potential of endothelial cells.
Nakao
M
M
Department of Pharmacology, Akita University School of Medicine, Akita 010-8543, Japan.
Ono
K
K
Fujisawa
S
S
Iijima
T
T
D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D002712:Chlorides / Q000502:physiology*; D004553:Electric Conductivity; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D006874:Hydrostatic Pressure; D018408:Patch-Clamp Techniques; D013314:Stress, Mechanical
D002121:Calcium Channel Blockers; D002712:Chlorides; D002118:Calcium