Method to denude rat aortic endothelium with saponin for phosphoinositide analysis in vascular smooth muscle

Arterial endothelium plays an essential role in modulating vascular tone through the production of vasoactive biogenic substances. To determine the effect of endothelial cell function on vascular smooth muscle receptor-effector coupling, a simple chemical techniques was devised to denude rat aortic endothelium while receptor function was preserved. Agonist-stimulated phosphatidylinositol turnover (PI) and vascular contractility were studied in saponin-treated aortic rings. Uniform removal of the aortic endothelial cell layer was readily verified with the use of a modified silver stain with light microscopy. Agonist-mediated PI turnover was statistically decreased in saponin-exposed aortic rings relative to control aorta. Increased contractile sensitivity in denuded aorta was also observed with norepinephrine (NE), phenylephrine (PE), and serotonin (5-HT). Thus, brief exposure to saponin is an effective chemical skinning technique that preserves vascular function.