茉莉花水提物对大鼠胸主动脉的舒张作用及机制

 目的 观察中药茉莉花水提物（AEJ）的血管舒张效应并探讨其机制。方法 采用大鼠胸主动脉环灌流，记录张力的变化；激光扫描共聚焦显微镜技术检测血管平滑肌细胞内 Ca2+浓度。结果 AEJ（0.375～6 g·L-1）能够浓度依赖性降低苯肾上腺素（PE，10 μmol·L-1)及 KCl (60 mmol·L-1)引起的主动脉环张力。在无钙环境下，AEJ 能抑制高浓度氯化钾 (KCl 60 mmol·L-1)环境下累计加入 CaCl₂(0.5～8 mmol·L-1)引起的收缩，抑制 PE (10 μmol·L-1) 引起的去内皮主动脉环的短暂收缩 (P<0.01)。钾通道阻断剂 4-氨基吡啶(5 mmol·L-1)可显著抑制 AEJ 的舒血管作用。激光扫描共聚焦检测细胞内 Ca2+的结果表明，AEJ 浓度依赖性（6，12 g·L-1）降低了 KCl 除极诱导的滑肌细胞胞浆内 Ca2+的升高幅度（P<0.05）。结论 AEJ 能够浓度依赖性舒张大鼠胸主动脉，其作用机制可能是减少 Ca2+经电压依赖性钙通道和受体操纵性钙通道流入血管平滑肌细胞及抑制内质网内 Ca2+释放有关；电压敏感型 K+通道（K_V）的激活部分参与了 AEJ 舒血管作用。

Vasodilation Effect of Aqueous Extract of Jasmine on Rat Thoracic Aorta and Its Related Mechanism

OBJECTIVE To investigate the vasodilative effect of aqueous extract of Jasmine（AEJ）, a kind of Chinese materia medica, and the possible mechanism. METHODS Isometric tension was recorded in isolated rat thoracic artery to study the vasodilation effect of AEJ.［Ca2+］_i was determined by laser scanning confocal microscope(LSCM). RESULTS AEJ (0.375～6 g·L-1) caused concentration-dependent relaxation of endothelium-intact or endothelium-denuded aorta rings precontracted with phenylephrine (PE, 10 μmol·L-1) or KCl (60 mmol·L-1). In Ca2+-free medium, AEJ decreased Ca2+-dependent (0.5-8 mmol·L-1) tension of thoracic aorta induced by high concentration of K+(60 mmol·L-1). It also reduced the contraction elicited by PE in Ca2+-free medium (P<0.01). 4-Aminopyridine（4-AP）(5 mmol·L-1), a voltage-dependent K+ channel inhibitor, attenuated the vasorelaxing effect of AEJ（P<0.01）. LSCM showed that ［Ca2+ ］_i increased by KCl was depressed by AEJ（6, 12 g·L-1）（P<0.05）. CONCLUSION AEJ exerted a dose-dependent vasorelaxant effect on rat isolated aorta rings. The mechanism is related to the inhibition of voltage-dependent Ca2+ channel (VDC) , receptor-operate Ca2+ channel (ROC) and release of Ca2+ from sarcoplasmic reticulum. The activation of K_V contribute partly to the endothelium-independent relaxation by AEJ.