title: Increase of empty pool-activated Ca2+ influx using an intracellular Ca2+ chelating agent.
abstract: We demonstrate here that stimulated 45Ca2+ influx in A7r5 vascular smooth muscle cells induced either by receptor activation with [Arg]8 vasopressin or by the SR-Ca(2+)-ATPase inhibitor thapsigargin was increased more than threefold if cells were preloaded with the intracellular calcium chelator BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid). The increased influx is probably due to an attenuation of negative feedback of Ca2+ on its own entry accompanied by increased Ca2+ storage capacity of BAPTA-loaded cells leading to diminished cellular Ca2+ release. We propose that BAPTA preloading could be a useful approach to investigate receptor-induced Ca2+ influx.
authors.affiliation: Pharmacology Group, School of Pharmacy, University of Lausanne, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Skutella
authors.forename: U T
authors.initials: UT
authors.lastname: Rüegg
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000502:physiology; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000737:chemistry; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002451:Cell Compartmentation; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D002614:Chelating Agents / Q000737:chemistry; D003593:Cytoplasm / Q000378:metabolism; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007093:Imidazoles / Q000737:chemistry; D007700:Kinetics; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D009543:Nifedipine / Q000031:analogs & derivatives / Q000737:chemistry; D051381:Rats; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin
chemical_list: D002121:Calcium Channel Blockers; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D007093:Imidazoles; D013729:Terpenes; D001127:Arginine Vasopressin; D004533:Egtazic Acid; D019284:Thapsigargin; D000252:Calcium-Transporting ATPases; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; D009543:Nifedipine; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; C034600:darodipine; D002118:Calcium