Depletion and refilling of intracellular Ca2+ stores induce oscillations of Ca2+ current.
An agonist-induced Ca2+ influx pathway in vascular endothelium and other nonexcitable cells is closely aligned with the depletion of microsomal Ca2+ stores. The mechanism by which this occurs is unknown. In these studies 2',5',-di(tert-butyl-1,4-benzohydroquinone, a specific inhibitor of the microsomal Ca(2+)-adenosinetriphosphatase, and patch-clamp recordings were used to evaluate the relationship of inward Ca2+ current to the depletion of intracellular Ca2+ stores. The results demonstrate that depletion and refilling of Ca2+ stores control the amplitude of an electrogenic influx pathway in vascular endothelium. Prominent fluctuations in Ca2+ current occur when there is an imbalance between depletion and refilling of the stores. Furthermore, the studies suggest that the Ca2+ influx pathway is spatially in close association with the intracellular store.
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Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030.
Kunze
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D000818:Animals; D001011:Aorta / Q000166:cytology / Q000502:physiology; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D015220:Calcium Channels / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000032:analysis / Q000502:physiology; D002417:Cattle; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology; D006873:Hydroquinones / Q000494:pharmacology; D008861:Microsomes / Q000201:enzymology
D015220:Calcium Channels; D006873:Hydroquinones; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C019359:2,5-di-tert-butylhydroquinone; D004533:Egtazic Acid; D000252:Calcium-Transporting ATPases; D002118:Calcium