C-type natriuretic peptide inhibits upregulation of alpha1-adrenoceptor and inositol 1,4,5-trisphosphate receptor in rat vascular smooth muscle after vascular endothelial injury.

OBJECTIVE: In a model of balloon injury of rat aortic endothelium, the effects of C-type natriuretic peptide (CNP) on alpha1-adrenoreceptor and inositol 1,4,5-triphosphate (IP3) receptor were studied. METHODS: Aortic injuries were produced by vascular endothelium-denudation. Alpha1-adrenoreceptor in smooth muscle sarcolemma and IP3 receptor in smooth muscle sarcoplasmic reticulum in the rat aorta were assayed by radioactive analysis method. RESULTS: It was found that neointima was formed and the contents of DNA, collagen and elastin of each intima-media were sigificantly increased in 7 days and 21 days after balloon injury of rat aorta. Alpha1-adrenoreceptor in smooth muscle sarcolemma and IF3 receptor in sarcoplasmic reticulum were also upregulated. Results also showed that the administration of CNP i.p. significantly decreased the contents of DNA, collagen and elastin of each intima-media, and inhibited the up-regulation of alpha1-adrenoreceptor and IP3 receptor. CONCLUSION: The inhibition of the up-regulation of alpha1-adrenoreceptor and IP3 receptor by CNP might be one of the mechanisms of its suppressive action on intimal proliferation.