title: Effects of brief and prolonged ischemia on eicosanoid synthesis in dog and rat hearts.
abstract: We compared the effects of brief and prolonged myocardial ischemia on tissue prostaglandin synthesis. Regional ischemia was induced in dogs and maintained for 5 or 30 minutes. Isolated rat hearts were subjected to global ischemia in a working heart preparation for periods of 5 or 20 minutes. De novo synthesis of prostaglandins PGE2 and PGF2 alpha was measured in endocardial and epicardial explants from hearts subjected to transient ischemia. After 5 minutes of coronary ligation, PGE2 production by the ischemic canine endocardium increased by 68%, compared with non-ischemic tissue, and PGF2 alpha levels rose by 29%. In isolated rat hearts, 5-minute ischemia increased endocardial rate of PGE2 synthesis (13.2 +/- 1.7 pmol/g/h, as compared with 6.7 +/- 0.5 under normoxic conditions). Ischemic stimulation of eicosanoid production by the endocardium was no longer apparent after 30-minute regional or 20-minute global ischemia. In contrast, the epicardium showed significant changes only after 30-minute ischemia and only with respect to PGF2 alpha (12.0 +/- 6.2 in the ischemic vs 7.1 +/- 3.2 pmol/g/h in the non-ischemic tissue). Ischemia-induced differences in prostaglandin production were attenuated in the presence of arachidonic acid or aspirin.
authors.affiliation: Laboratory of Cardiac Metabolism, Sheba Medical Center, Tel-Hashomer, Israel.
authors.forename: B
authors.initials: B
authors.lastname: Rabinowitz
authors.forename: M
authors.initials: M
authors.lastname: Arad
authors.forename: A
authors.initials: A
authors.lastname: Shotan
authors.forename: R
authors.initials: R
authors.lastname: Klein
authors.forename: Y
authors.initials: Y
authors.lastname: Har Zahav
authors.forename: E
authors.initials: E
authors.lastname: Elazar
mesh_terms: D000818:Animals; D015237:Dinoprost / Q000096:biosynthesis; D015232:Dinoprostone / Q000096:biosynthesis; D004285:Dogs; D015777:Eicosanoids / Q000096:biosynthesis*; D004699:Endocardium / Q000378:metabolism; D066298:In Vitro Techniques; D017202:Myocardial Ischemia / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D011453:Prostaglandins / Q000096:biosynthesis; D051381:Rats; D013997:Time Factors
chemical_list: D015777:Eicosanoids; D011453:Prostaglandins; D015237:Dinoprost; D015232:Dinoprostone