和厚朴酚对SD大鼠离体胸主动脉环的作用

Effect of honokiol on thoracic aorta rings isolated from SD rats

目的观察和厚朴酚对SD大鼠离体胸主动脉环的作用,并探讨其作用机制。方法采用大鼠胸主动脉环离体灌流技术,观察和厚朴酚对内皮完整及内皮去除的血管环在基础状态(2.5 g张力)、苯肾上腺素及氯化钾预收缩状态下的作用。并用左旋硝基精氨酸甲酯、吲哚美辛处理血管环,观察和厚朴酚影响血管张力的机制。结果和厚朴酚对血管基础张力无明显影响,能剂量依赖地缓慢舒张高钾、苯肾上腺素(phenylephrine,PE)引起去内皮血管环收缩;对PE引起内皮完整血管呈快速(2 min)、缓慢(15min)双相舒张作用;快速舒张作用不受吲哚美辛影响,而可被一氧化氮合酶抑制剂左旋硝基精氨酸甲酯完全阻断。结论和厚朴酚对离体血管环具有舒张作用,并增强一氧化氮作用而不影响前列环素。

Objective To investigate the effect of honokiol on thoracic aorta rings isolated from SD rats.Methods Isometric tension recording was applied to evaluate the effect of honokiol on aortic rings under resting,phenylephrine（PE）-preconstricting or KCl-preconstricting conditions with or without the endothelium.Treating with L-N（w）-nitro-arginine methyl ester（L-NAME） and indomethacin,the underlying mechnism of vasorelaxation-induced by honokiol was determined.Results Honokiol exhibited negligible vasomotor action on aortic rings with or without endothelium at resting tension.Honokiol showed a dose-dependent relaxation on endothelium-denuded aortic rings stimulated by KCl or PE.Honokiol caused a two-phases（fast in 2 min and slow in 15 min） relaxation on endothelium-intact rings stimulated by PE.The fast relaxation was completely antagonized by L-NAME,but not by indomethacin.Conclusion Honokiol shows a relaxing effect on vascular smooth muscle,which mechanism is related to upregulation of NO bioactivity.