Vascular Actions of Serotonin in Large and Small Arteries are Amplified by Loss of Endothelium, Atheroma and Hypertension

Abstract

Free serotonin (5-hydroxytryptamine; 5-HT) levels in blood are kept low because platelets avidly trap the autacoid released from neuronal or enterochromaffin cells. If platelets aggregate and release serotonin at sites of atheroma or endothelium denudation, the artery wall will generally constrict. The discovery that endothelial cells can release endothelium-derived relaxing factor (EDRF), a powerful relaxant now known to be NO (Palmer et al., 1987), has stimulated much work in trying to unravel the complex interactions that can occur for serotonin within the artery wall in large and small vessels.