SEROTONIN (5-HYDROXYTRYPTAMINE, 5-HT) ENHANCES MIGRATION OF RAT AORTIC SMOOTH-MUSCLE CELLS THROUGH 5-HT2 RECEPTORS

The effects of serotonin on migration of cultured rat aortic smooth mu scle cells (SMC) were studied to clarify the role of this substance in the pathogenesis of atherosclerosis. Serotonin alone did not stimulat e SMC migration but stimulated it at physiological concentrations in t he presence of other migration factors such as SMC-derived migration f actor, platelet-derived migration factor and fibronectin. Checker-boar d analysis revealed that the serotonin effect was chemotactic. Moreove r, serotonin effects were completely abolished by a selective inhibito r of the 5-HT2 receptor (MCI-9042), indicating that serotonin effects were mediated through the 5-HT2 receptor pathway. Finally, serotonin e ffects were also abolished by a phospholipase C inhibitor, U73122, sug gesting that the 5-HT2 receptor mediated signal of serotonin was trans duced by PLC. The results suggest that platelet-derived serotonin play s some role in the SMC dominant neointima formation. (C) 1997 Elsevier Science Ireland Ltd.