Cocaine-stimulated endothelin-1 release is decreased by angiotensin-converting enzyme inhibitors in cultured endothelial cells

Objective: The primary aim was to determine the action of pathophysiologically relevant cocaine concentrations (10(-7)-10(-5) M) on endothelin-1 (ET-1) release from cultured endothelial cells under various cellular conditions. Further aims were to evaluate the effect of angiotensin-converting enzyme inhibitors on cocaine-treated endothelial cells, to assess their potential for inhibition of ET-1-stimulated release. Methods: Endothelin-1 release into the media was evaluated by radioimmunoassay under basal conditions and after 24 h treatment of endothelial cells with cocaine hydrochloride (HCl), or cocaine HCl and ACE inhibitors, captopril and lisinopril. The effect of serum and plasma under these conditions was also investigated. Results: Cocaine HCl stimulated ET-1 release in a dose response fashion that was independent of plasma or serum factors. Furthermore, cocaine-stimulated ET-1 release was inhibited by administration of angiotensin-converting enzyme inhibitors captopril and lisinopril. Conclusions: These findings suggest that cocaine can directly stimulate endothelial cells to release ET-1 and that the observed increase is independent of serum or plasma factors. Furthermore, cocaine-stimulated endothelin-1 release appears to be mediated at least in part by the angiotensin system. These observations provide a framework for understanding the cellular mechanisms involved in cocaine-induced vasoconstriction.