Role of leukotrienes on coronary vasoconstriction in isolated hearts of arthritic rats: effect of in vivo treatment with CI-986, a dual inhibitor of cyclooxygenase and lipoxygenase.

In this study, coronary perfusion pressure and force of contraction were investigated in isolated hearts removed from arthritic rats by using the Langendorff method. A strong coronary vasoconstriction was determined in arthritic hearts which was associated with elevated levels of arachidonate 5-lipoxygenase (5-LOX) products, leukotriene B(4) (LTB(4)) and LTC(4) in coronary effluents. In vivo treatment with the dual inhibitor of cyclooxygenase (COX) and LOX, CI-986 (2 and 10 mg/kg/day) on days 14- 26 following adjuvant injection, prevented the coronary vasoconstriction and the increased production of LTB(4) and LTC(4). These results suggest that the coronary vasoconstriction in the isolated arthritic hearts is associated with an increased activity of the LOX system and CI-986 could have a preventive effect on constriction of coronary arteries. Copyright 2000 S. Karger AG, Basel