AN ENZYME THAT ACTIVATES RENAL PRORENIN PROMOTES ENDOTHELIUM-INDEPENDENT VASORELAXATION IN RABBIT AORTA

MARIA DE LOS ANGELES PERAL; PAULA, V.; ROMANO, LILIANA; COVIELLO, A; EDUARDO, V.

AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY

The American physiological Society

Lugar: Am. J. Physiol. Soc; Año: 2003 vol. 284 p. 704 - 710

0363-6135

Abstract: The effect of a novel enzyme(PreR-Co) that activates renal prorenin was studied on rabbitaortas with and without endothelium. It was tested 1) in the basal tone of nonstimulated or ANG II-sensitized rings orrings precontracted with norepinephrine (NE), PGF2, high KCl concentration, and 2) in rings pretreated with enalaprilat, losartan, PD-123319, N-nitro-L-arginine methyl ester, HOE-140, indomethacin, or serine protease inhibitors (PMSF,aprotinin, or soybean trypsin inhibitor); kallilkrein and bradykininwere also tested in ANG II-sensitized rings. PreR-Co produced a vasorelaxant effect in the basal tone and in the precontracted rabbit aorta. The effect was endothelium independent, potentiated by endothelium removal or nitric oxide (NO) synthase inhibition, and abolished by boiling the enzyme. In addition, the effect improved when basal tone was increased in ANG II-sensitized aortic rings or in precontracted vessels. No activation of the ANG II, bradykinin, prostaglandin, or NO  pathway mediating the PreR-Co response could be obtained, suggesting a direct action of the enzyme. This action seems to be dependent on esterasic activity because serine protease inhibitors like PMSF and aprotinin were able to block the vasorelaxant effect of PreR-Co.  Key Work : renin activators; vasorelaxant activity; rabbit aorta