Chloride-sensitive Ca2+ entry by histamine and ATP in human aortic endothelial cells.
The regulation of intracellular free Ca2+ concentration ([Ca2+]i) was studied in cultured human aortic endothelial cells loaded with the fluorescent Ca2+ indicator fura-2. Histamine and ATP at concentrations of 10 microM and higher produced a biphasic change in [Ca2+]i, which consisted of an initial transient elevation followed by a sustained elevation. Reduction of the extracellular Cl- concentration to 40 mM, or exposure to the Cl- channel antagonist N-phenylanthranilic acid selectively prevented the sustained response to histamine or ATP, but they did not affect the sustained response to the Ca2+ ionophore ionomycin. Elevation of extracellular K+ concentration to 90 mM had no influence on the sustained response to histamine or ATP. These results suggest that the sustained elevation of [Ca2+]i in response to histamine and ATP is due to the Cl(-)-sensitive entry of extracellular Ca2+ in cultured human aortic endothelial cells.
Hosoki
E
E
Department of Pharmacology, Akita University School of Medicine, Japan.
Iijima
T
T
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D001011:Aorta / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D018118:Chloride Channels / Q000037:antagonists & inhibitors; D002712:Chlorides / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016257:Fura-2 / Q000737:chemistry; D006632:Histamine / Q000494:pharmacology*; D006801:Humans; D015759:Ionomycin / Q000494:pharmacology
D018118:Chloride Channels; D002712:Chlorides; D015759:Ionomycin; D006632:Histamine; D000255:Adenosine Triphosphate; D002118:Calcium; D016257:Fura-2