Endothelium-dependent relaxant effect of thrombin on isolated pig coronary arteries.
In pig coronary arteries with intact endothelium the clotting enzyme thrombin at physiologically relevant concentrations caused a reversible transient and concentration-dependent relaxation of PGF2 alpha-precontracted vessels which was absent in case of mechanically removed endothelium. The thrombin-induced relaxation was not affected by indomethacin. Exposure of the coronary arteries to a calcium-free medium or preincubation with verapamil led to the reduction of the PGF2 alpha-induced contraction while the relaxant effect of thrombin was only slightly inhibited. However, the guanylate cyclase inhibitor methylene blue diminished the relaxant response to thrombin. The specific tight-binding thrombin inhibitor hirudin prevented the relaxant effect of thrombin in a concentration-dependent manner.
Glusa
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Institute of Pharmacology and Toxicology, Medical Academy Erfurt, G.D.R.
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology*; D015237:Dinoprost / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000502:physiology*; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D013552:Swine; D013917:Thrombin / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D015237:Dinoprost; D013917:Thrombin; D001920:Bradykinin