Cyclopiazonic acid stimulates Ca2+ influx through non-specific cation channels in endothelial cells.
A non-specific cation channel in cultured human umbilical vein endothelial cells was obtained by cell-attached patch-clamp study. This channel showed a conductance of 28 pS when both pipette and bath contained 140 mM potassium chloride. when pipette solution was changed into 140 sodium chloride with 5 mM calcium chloride, the conductance was 26 pS. when 120 mM calcium chloride was used as the only cation in the pipette, a conductance of 6 pS was obtained. Bath application of cyclopiazonic acid, an inhibitor of the sarcoplasmic reticulum Ca2+ pump in smooth muscle and other tissues, dose dependently activates this non-specific cation channel. It is assumed that cyclopiazonic acid by blockade of the refilling of Ca2+ stores depletes the rapidly exchanging intracellular Ca2+ stores and this action stimulates Ca2+ influx through the non-specific cation channels in human umbilical vein endothelial cells.
Zhang
H
H
Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.
Inazu
M
M
Weir
B
B
Buchanan
M
M
Daniel
E
E
D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D002412:Cations; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D007424:Intracellular Fluid / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects* / Q000378:metabolism*; D009183:Mycotoxins / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000494:pharmacology; D013268:Stimulation, Chemical
D002412:Cations; D007211:Indoles; D007473:Ion Channels; D009183:Mycotoxins; D012965:Sodium Chloride; D000252:Calcium-Transporting ATPases; D002122:Calcium Chloride; D002118:Calcium; C000543:cyclopiazonic acid