[The role of endothelin in the contractile reactions of vascular smooth muscles in hypertensive rats]

Abstract

Experiments on isolated strips of rat v. portae revealed that endothelin participates in the development of myogenic reactions of vascular smooth muscles. Endothelin is known to be released by endotheliocytes and to stimulate the contraction of vascular smooth muscle cells. Rats with inherited arterial hypertension showed significant decrease of the stimulating effect of endothelin-1 upon the contraction of vascular smooth muscles. At the same time, the effect of phosphoramidon, an inhibitor of endothelin-converting enzyme, upon the length-tension curve of the strips of v. portae is more marked in hypertensive vs. control rats. The data obtained testify to the fact that the increase of vascular tone in the hypertensive rats is most likely to be conditioned by the involvement of endothelin.