Pharmacological evidence that potentiation of plasmalemmal Ca2+-extrusion is functionally coupled to inhibition of SR Ca2+-ATPases in vascular smooth muscle cells

Cyclopiazonic acid (CPA), a specific inhibitor of sarcoplasmic reticulum (SR) Ca2+-ATPases, causes slowly developing and subsequently diminishing characteristic contractions in vascular smooth muscle, and the second application of CPA has incompletely repeatable effects, depending on the vessel type. The objective of the present study was to examine the mechanisms underlying the significant decrease of CPA-induced contractions upon the second …