SOMATOSTATIN RECEPTOR EXPRESSION IN RAT ILIAC ARTERIES AFTER BALLOON INJURY

Somatostatin is a general inhibitory hormone that exerts its effects t hrough five functionally distinct receptor subtypes (SSTR1-5). Somatos tatin analogues have been shown to be effective in inhibiting intimal hyperplasia after balloon induced vascular injury. However, the exact SSTR subtype responsible for the inhibitory effect of somatostatin on intimal hyperplasia is unknown. The purpose of this study was to defin e the presence and abundance of SSTR subtypes in a rat iliac balloon i njury model of intimal hyperplasia. Transaortic balloon injury of the rat iliac artery was carried out. Rats were sacrificed at 48 h, 1 week , and 1 month postinjury, and perfusion fixed and stained with antibod ies against SSTR2, 3, and 5. SSTR2 was identified on the intimal surfa ces of normal and injured vessels. SSTR2 immunoreactivity was more pro minent at 1 week and 1 month postinjury compared with 48 h postinjury. There was no immunostaining with SSTR3 and SSTR5 antibodies. The resu lts show that SSTR2 is expressed on endothelial cells in normal and in jured rat vessels. Its abundance in the injured vessel was increased u p to 1 month postinjury.