Increased endothelin ETA receptor expression in rat carotid arteries after balloon injury

Endothelins are vasoactive peptides and are believed to act as vascular smooth muscle mitogens. Vascular injury results in medial smooth muscle migration and proliferation with the formation of a neointima. Using quantitative autoradiography, we examined the expression of endothelin receptor subtypes ETA and ETB in the rat carotid artery 2, 8, and 16 days after balloon- catheter injury. At two and eight days after balloon catheterization, ETA receptor expression was significantly increased in the media of the injured vessel when compared to that in the media of the intact vessel. The enhanced expression of receptors returned to normal levels by 16 days after the injury. Neointimal cells also expressed ETA receptors at a lower lever than that expressed by the injured media 8 days after injury, and continued to express ETA receptors 16 days after the injury. ETB receptors were not detectable in the media or the neointima at any time after the injury. Our results suggest that ETA receptors may have a significant role in injury induced vascular smooth muscle proliferation and neointima formation. Published by Elsevier Science Inc.