Hormone interactions in the isolated rabbit heart. Synthesis and coronary vasomotor effects of prostaglandins, angiotensin, and bradykinin

P. Needleman, G. R. Marshall, B. E. Sobel

Research output: Contribution to journalArticle

123 Scopus citations

Abstract

In the present study, the synthesis and degradation of several potent vasoactive substances influencing coronary resistance were characterized in the isolated perfused rabbit heart. Prostaglandin synthetase activity, angiotensin converting enzyme activity, and bradykininase activity (without angiotensinase) were observed. A prostaglandin E2 like substance appeared to be the endogenous mediator of the coronary vasodilation produced by bradykinin and angiotensin II (AII). The concentration of this prostaglandin like substance in the coronary venous effluent was directly proportional to the concentration of the coronary vasodilator stimulus (bradykinin or AII). The prostaglandinlike substance released and the coronary dilatation produced by the agonists correlated temporally and quantitatively. Abolition of cardiac biosynthesis of the prostaglandinlike substance by indomethacin also abolished the decrease in coronary resistance produced by the agonists. AII, the most potent naturally occurring vasoconstrictor substance, produced a paradoxical coronary vasodilation because it stimulated cardiac prostaglandin biosynthesis, but the direct coronary vasoconstrictor action of AII could be readily unmasked by indomethacin, which blocks prostaglandin synthesis. The nonapeptide SQ-20881 blocked cardiac biosynthesis of AII (from angiotensin I) and enhanced the coronary vascular effects of bradykinin by interfering with bradykininase activity. Similarly, the AII-receptor antagonist, 1-Sar-8-Ile-AII, blocked the coronary vascular effects of AII.

Original languageEnglish
Pages (from-to)802-808
Number of pages7
JournalCirculation research
Volume37
Issue number6
DOIs
StatePublished - Jan 1 1975

Fingerprint Dive into the research topics of 'Hormone interactions in the isolated rabbit heart. Synthesis and coronary vasomotor effects of prostaglandins, angiotensin, and bradykinin'. Together they form a unique fingerprint.

  • Cite this