ATP-induced chloride current and tonic increase of internal Ca2+ concentration in vascular endothelial cells.
The effect of ATP on membrane currents and the intracellular Ca2+ concentration was investigated in cultured human aortic endothelial cells. ATP (10 microM) activated the Cl- current within a few minutes following a rapid activation of the K+ current. Fura-2 fluorometry showed that ATP increased [Ca2+]i with a biphasic time course. The tonic phase was markedly depressed by both an increase in [K+]o to 140 mM and a decrease in [Cl-]o to 20 mM. ATP activated not only Ca(2+)-activated K+ channels but also Cl- channels to regulate the membrane potential related to the tonic phase of the [Ca2+]i increase.
Yumoto
K
K
Department of Physiology, Juntendo University School of Medicine, Tokyo, Japan.
Watanabe
M
M
Yamaguchi
H
H
Ochi
R
R
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D001011:Aorta / Q000502:physiology; D002118:Calcium / Q000494:pharmacology*; D018118:Chloride Channels / Q000502:physiology*; D004727:Endothelium / Q000502:physiology*; D016257:Fura-2; D006801:Humans; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology
D018118:Chloride Channels; D015221:Potassium Channels; D000255:Adenosine Triphosphate; D002118:Calcium; D016257:Fura-2