THROMBIN-INDUCED ENDOTHELIUM-DEPENDENT RELAXATION AND ITS INHIBITION BY LDL IN PORCINE CORONARY ARTERIES

概要

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The effects of thrombin on the vascular tone of porcine coronary arteries and the influence of LDL on the thrombin effects were investigated. A segment of porcine coronary arteries was mounted under 1.5 g resting tension to measure the isometric force. LDL was prepared from porcine serum by ultracentrifugation and dialysis against Tyrode buffer. Thrombin (0.1-0.3 U/ml) dose-dependently relaxed intact porcine coronary arteries precontracted with PGF_2α (10^<-5> M). The removal of the endothelium by rubbing abolished the thrombin effect. This relaxation was also abolished by methylene blue (10^<-5> M), but was unaffected by indomethacin (5x10^<-5> M). At these concentrations, thrombin per se exerted a slight contractile effect on the resting tension of the coronary arteries with or without the endothelium. An addition of LDL (1 mg protein /ml) to the solution did not affect the precontraction of PGF_2α. However, LDL dose-dependently inhibited the thrombin-induced relaxation of coronary arteries precontracted with PGF_2α. Albumin (1 mg protein/ml) lacked such effects. Relaxation by sodium nitroprusside (10^<-6> M) was unaffected by the LDL-treatment. These results suggest that LDL, a major atherogenic factor, directly influences the endothelium-dependent vasodilation by thrombin in the coronary arteries.
社団法人日本薬学会の論文
1988-11-25