Comparison of functional responses of canine coronary artery and saphenous vein

Autor: Isshiki, Takaaki, Akatsuka, Nobuharu, Saito, Teruo, Tsuneyoshi, Hideo, Ohno, Minoru, Nakamura, Masato, Namiki, Takashi, Oka, Hiroshi
Zdroj: Cardiovascular Drugs and Therapy; September 1988, Vol. 2 Issue: 3 p325-331, 7p
Abstrakt: Functional responses of canine circumflex coronary arteries and saphenous veins before and after grafting surgery were assessed following physiologic and pharmacologic intervensions. Developed tension of ringed segments of vessels was recorded isometrically. Dose-dependent responses to norepinephrine revealed significantly greater responses of saphenous veins than coronary arteries (maximal responses were 2.79±0.45 and 0.44±0.34 g, respectively; p<0.001). Sensitivity to norephinephrine [as evaluated by 50% effective dose (ED50) value] was 3.3 times greater in the saphenous veins (p<0.001). STA2, a synthetic thromboxane A2 analog (see Methods), produced similar contractions of both vessels [maximal responses were 2.13±0.37 g in saphenous vein and 1.64±0.85 g in coronary artery; p < not significant (NS)], while sensitivity to STA2 of saphenous veins was 3.1 times greater than that of coronary arteries (p<0.001). In contrast to the foregoing responses, coronary arteris demonstrated significantly greater responses to potassium than saphenus veins (maximal responses were 2.16±0.71 g and 1.40±0.56 g, respectively; p<0.001). Moreover, coronary arteries revealed 1.6 times greater sensitivity than saphenous veins (p<0.001). When saphenous veins were transplanted into the femoral artery, the segments of the grafts (2 weeks or 3 months after surgery) revealed 4.0 and 1.7 times greater sensitivity (denervation supersensitivity) to norepinephrine and potassium than those of the control veins (p<0.01, respectively). Contractile tension response, however, decreased by at least 50% 3 months after surgery, most probably due to a thickened vessel wall and a reduced compliance. Thus, the functional characteristics of the saphenous vein, which were totally different from those of the coronary artery, seemed to be preserved even after grafting except for denervation supersensitivity, which may modify the differences between the two vessels. Those differences may be relevant to the control of the coronary circulation after coronary bypass surgery.
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