[目的]探讨血根碱对兔离体肠平滑肌的舒张作用及机制.[方法]采用离体肠肌试验,应用BL-420E生物机能实验系统,比较血根碱对正常肠肌及工具药乙酰胆碱、酚妥拉明、氯化钡作用下兔离体肠平滑肌活动的影响,记录肠肌的收缩频率和振幅,并计算抑制率.[结果]血根碱可浓度依赖性的抑制兔小肠平滑肌自发性收缩的频率和振幅.0.4 mg·mL-1的血根碱对由乙酰胆碱、氯化钡引起的离体肠肌的兴奋性收缩有明显的拮抗作用,而对酚妥拉明阻断肾上腺素能受体后,仍能显著降低离体肠平滑肌收缩的振幅.[结论]血根碱对小肠平滑肌的舒张作用可能与乙酰胆碱竞争,阻断M受体、与酚妥拉明竞争,兴奋α受体及直接抑制肠肌兴奋性有关.%[ Objective ] The objective of this study was to investigate the relaxant effect of sanguinarine on intestinal smooth muscle contractions and the mechanisms involved. [Method] The experiments were performed in isolated intestinal smooth muscle of rabbits. Inhibitory effects of sanguinarine on contraction of normal intestinal smooth muscle and on that of the intestinal muscle treated with acetylcholine (ACh), phentolamine and Barium Chloride (BaCl2) were compared by analyzing the frequency and amplitude of contractions. [Result] Results showed that sanguinarine significantly inhibited the frequency and amplitude of spontaneous contraction of isolated intestinal smooth muscle in a dose-dependent manner. The intestinal smooth muscle contractions caused by Ach and Bacl2 was abolished by sanguinarine (0.4 mg-mL-1), and the frequency and amplitude of the intestinal smooth muscle contraction induced by phentolamine (a-receptor antagonist) decreased after incubation with sanguinarine. [Conclusion] These results suggest that the mechanism of relaxant effect of sanguinarine on intestinal smooth muscle contractions may be related to the blockage of M receptor by competing with ACh, to the excitement of a-receptor through competing with phentolamine and to the direct inhibit on of the motility of intestinal smooth muscle.
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