论文部分内容阅读
目的:研究罗布麻叶提取物(extracts from leaves of Apocynum venetum,ELA)对离体大鼠胸主动脉环的作用及其可能的机制。方法:采用累积加药法,观察ELA对苯肾上腺素(PE)预收缩的主动脉环张力的影响;观察hemoglobin,亚甲蓝(MB)预处理对ELA扩血管作用影响;观察左旋硝基精氨酸甲酯盐酸盐(L-NAME),甲基异硫脲硫酸盐(SMT)预处理对ELA的扩血管作用的影响;观察四乙胺(TEA),4-氨基吡啶(4-AP)和格列苯脲(GLB)对ELA的血管舒张作用的影响;采用Ca2+剥夺和复加法,观察ELA对细胞内钙释放和外钙内流所引起的血管环收缩反应的作用。结果:ELA可显著舒张PE预收缩的主动脉环,低浓度下(1×10-6～3×10-4)g.mL-1为内皮依赖性作用,而高浓度下(3×10-4,1×10-3)g.mL-1则为内皮非依赖性舒张。低浓度下(1×10-6～3×10-4)g.mL-1,ELA的扩血管作用可被Hemoglobin,MB(P<0.05)和L-NAME,SMT(P<0.05)阻断。高浓度下(3×10-4～3×10-3)g.mL-1,ELA可显著抑制细胞内钙释放和细胞外钙内流(P<0.05);钾通道阻滞剂TEA,4-AP和格列苯脲可不同程度地阻断ELA扩血管作用。结论:ELA可剂量依赖性的舒张PE预收缩的胸主动脉环,呈现低浓度下内皮依赖、高浓度下内皮非依赖的特点。低浓度下ELA的血管舒张作用可能与NO释放有关,高浓度下其作用需要Ca2+,K+通道参与。
Objective: To study the effect of extract from leaves of Apocynum venetum (ELA) on the thoracic aortic rings in isolated rat and its possible mechanism. Methods: The effects of ELA on precontracted aortic ring tension of phenylephrine (PE) were observed by cumulative dosing method. The effects of hemoglobin and methylene blue pretreatment on vasodilation of ELA were observed. (L-NAME) and methyl isothiourea sulfate (SMT) preconditioning on the vasodilatation of ELA were observed. The effects of tetraethylammonium (TEA), 4-aminopyridine ) And glibenclamide (GLB) on the vasorelaxing effect of ELA. Ca2 + deprivation and triple addition were used to observe the effect of ELA on vasoconstriction induced by intracellular calcium release and extracellular calcium influx. RESULTS: ELA markedly aprolonged PE precontracted aortic rings. Under low concentration (1 × 10-6 ~ 3 × 10-4) g.mL-1, it was endothelium-dependent, while high concentration (3 × 10- 4,1 × 10-3) g.mL-1 is endothelium-independent relaxation. The vasodilator effect of ELA was blocked by Hemoglobin, MB (P <0.05) and L-NAME, SMT (P <0.05) at low concentration of 1 × 10-6 ~ 3 × 10-4 g.mL- . ELA significantly inhibited intracellular calcium release and extracellular calcium influx (P <0.05) at high concentration (3 × 10-4 ~ 3 × 10-3) g.mL-1; potassium channel blocker TEA, 4 -AP and glibenclamide can block the ELA vasodilator effect to varying degrees. CONCLUSION: ELA can dose-dependently relax the pre-contractile thoracic aortic rings of PE, showing endothelium-dependent and endothelium-independent characteristics at low concentrations. The vasodilatory effect of ELA at low concentration may be related to the release of NO, and the action of ELA at high concentration requires Ca 2+ and K + channels.