Role of ET-1 and its receptors in the impairment of vascular functions in the cardiomyopathic hamster

Abstract

The objective of this study was to verify whether the response to ET-1 in the intact aorta of a normal hamster is different than that of a CMP hamster and, if so, whether the difference depends on the presence of the vascular endothelium. We also wanted to verify if the contribution of ET-1 receptors (ET[indice inférieur A] and/or ET[indice inférieur B]) in the vascular endothelium and vascular smooth muscle cells (VSMCs) undergoes changes during the development of CMP in the hamster. Our results suggest that there is a difference in the responsiveness to ET-1 stimulation in aortas from CMP hamsters compared to those from normal hamsters. This difference in responsiveness to ET-1 could be due, in part, to an increase in ET[indice inférieur B] receptor density in vascular endothelial cells. This may result in an increase in the synthesis and release of NO that, in turn, produces a large relaxation and opposes the vasoconstrictive effect of ET-1."--Résumé abrégé par UMI.