20-HETE relaxes bovine coronary arteries through the release of prostacyclin. Hypertension 1998 Jan;31(1 Pt 2):237-41
Date
02/07/1998Pubmed ID
9453309DOI
10.1161/01.hyp.31.1.237Scopus ID
2-s2.0-0031935515 (requires institutional sign-in at Scopus site) 40 CitationsAbstract
Neutrophils respond to ischemic injury by infiltrating the myocardium via the vascular wall. During this process, neutrophils are activated and release inflammatory mediators. Some of these mediators are metabolites of arachidonic acid. We have reported that neutrophils metabolize arachidonic acid to 20-HETE, a cytochrome P450 metabolite. We investigated the effects of 20-HETE on coronary vascular tone by examining 20-HETE-induced changes in isometric tension in bovine coronary artery rings precontracted with the thromboxane-mimetic, U46619. 20-HETE relaxed precontracted coronary rings in a concentration-dependent manner (EC50 of 3 x 10(-7) mol/L). Pretreatment with indomethacin, a cyclooxygenase inhibitor, shifted the concentration-response curve to the right (EC50 of 1 x 10(-6) mol/L); maximal relaxations were not affected. This suggested that 20-HETE-induced relaxations were, in part, dependent on the cyclooxygenase pathway. Relaxations to 20-HETE were not significantly changed in endothelium-denuded rings. To determine whether metabolism of 20-HETE to a vasoactive compound might explain the relaxations caused by 20-HETE, rings of coronary artery were incubated with [3H] 20-HETE. The incubation buffer was extracted and the [3H] products resolved on reverse-phase HPLC. Both denuded and intact arteries failed to metabolize [3H] 20-HETE. To investigate whether 20-HETE-induced relaxations were related to release of prostacyclin, we measured the release of 6-keto PGF1alpha, the stable metabolite of prostacyclin, from bovine coronary arteries. 20-HETE (1 x 10(-6) mol/L) stimulated an increase in 6-keto PGF1alpha in intact vessels (908 +/- 138 pg/mL versus 1402 +/- 157 pg/mL, basal versus stimulated). Thus, 20-HETE-induced relaxations are due, in part, to the stimulation of the release of the dilatory prostanoid, prostacyclin.
Author List
Pratt PF, Falck JR, Reddy KM, Kurian JB, Campbell WBAuthor
William B. Campbell PhD Professor in the Pharmacology and Toxicology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid6-Ketoprostaglandin F1 alpha
Animals
Bradykinin
Cattle
Coronary Vessels
Epoprostenol
Hydroxyeicosatetraenoic Acids
In Vitro Techniques
Isometric Contraction
Muscle Tonus
Muscle, Smooth, Vascular
Vasodilation
