Schultheiss G, Diener M
Institut für Veterinär-Physiologie, Universität, Giessen, Germany.
Zentralbl Veterinarmed A. 1999 Mar;46(2):123-31. doi: 10.1046/j.1439-0442.1999.00200.x.
The effect of inhibitors of the thromboxane A2 pathway on spontaneous contractions of intestinal smooth muscle preparations was studied. The thromboxane A2 antagonists Bay u3405, SK and F 88046 and KW-3635 concentration-dependently inhibited both the amplitude and the frequency of spontaneous contractions of the longitudinal muscle from the rat proximal colon. A concentration-dependent inhibition of the myogenic contractions was also observed with the thromboxane A2 synthase inhibitor U-51605, and with the combined cyclooxygenase/lipoxygenase inhibitor nordihydroguaiaretic acid, whereas indomethacin, a pure cyclooxygenase inhibitor, was ineffective. None of these inhibitors affected the contractile response evoked by the cholinergic agonist carbachol, excluding non-specific actions on intestinal motility. A similar response was observed for the rabbit jejunum, which, in contrast to the rat colon, exhibits more regular, high-frequency spontaneous contractions, which were inhibited by Bay u3405, SK and F 88046 and KW-3635 in a concentration-dependent manner, whereas the response to carbachol remained unaffected. These results suggest a role for thromboxane A2 in the generation and/or facilitation of spontaneous smooth muscle contractions in the gut.
研究了血栓素A2途径抑制剂对肠平滑肌制剂自发收缩的影响。血栓素A2拮抗剂Bay u3405、SK和F 88046以及KW-3635浓度依赖性地抑制大鼠近端结肠纵肌自发收缩的幅度和频率。血栓素A2合酶抑制剂U-51605以及环氧合酶/脂氧合酶联合抑制剂去甲二氢愈创木酸也观察到对肌源性收缩的浓度依赖性抑制，而纯环氧合酶抑制剂吲哚美辛则无效。这些抑制剂均未影响胆碱能激动剂卡巴胆碱引起的收缩反应，排除了对肠道运动的非特异性作用。对兔空肠观察到类似反应，与大鼠结肠不同，兔空肠表现出更规则、高频的自发收缩，Bay u3405、SK和F 88046以及KW-3635以浓度依赖性方式抑制这些收缩，而对卡巴胆碱的反应未受影响。这些结果表明血栓素A2在肠道平滑肌自发收缩的产生和/或促进中起作用。
