Cyclopiazonic acid causes endothelium-dependent relaxation in rat aorta.

The effects of cyclopiazonic acid (CPA), a selective inhibitor of Ca(2+)-pump ATPase for endoplasmic reticulum (ER), on the contractility of rat aorta with and without intact endothelium were studied to investigate the possible involvement of endothelial ER Ca(2+)-pump in the release of endothelium-derived relaxing factor (EDRF), which is known to cause vascular relaxation or inhibition of phenylephrine (PE)-precontracted aorta. When added to …