PROSTAGLANDIN-LIKE SUBSTANCES IN CORONARY VENOUS-BLOOD FOLLOWING MYOCARDIAL ISCHEMIA

  • 1 January 1976
    • journal article
    • research article
    • Vol. 199  (3) , 611-619
Abstract
Twelve anesthetized open chest dogs received an intracoronary infusion of 20 .mu.Ci of 3H-arachidonic acid through the left anterior descending coronary artery. A control blood sample was then taken from the great cardiac vein. The left anterior descending coronary artery was occluded for 10 min and then released. A 2nd cardiac vein blood sample was obtained during the coronary reactive hyperemic response. The pre- and postocclusion blood samples were analyzed for prostaglandin (PG)-like substances using TLC and analysis for radioactivity. There was an increase in PGE2- and PGA2-like substances, and arachidonic acid found in the postocclusion samples. PGE2 appears to be the predominant PG formed. Three animals received 10 mg/kg of indomethacin i.v. 1 h before the 3H-arachidonic acid infusion. Pretreatment with indomethacin abolished the release of PGE2 and PGA2-like substances but not arachidonic acid and reduced the reactive hyperemic response in magnitude and duration. Reactive hyperemia after a 10 min occlusion was studied in 5 dogs before and 1 h after the i.v. administration of 10 mg/kg of indomethacin. The control coronary flow and peak reactive hyperemic response were significantly reduced by the indomethacin. These studies suggest that myocardial ischemia promotes the synthesis and release of PG-like substances which may play a role in reactive hyperemia.

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