芍药苷对大鼠离体胸主动脉血管环的作用及其机制

Effects of Paeoniflorin on Isolated Thoracic Aorta Rings of Rats and Its Possible Mechanism

摘要:

目的: 观察芍药苷(paeoniflorin,PF)对大鼠离体胸主动脉血管的舒张作用并探讨其机制。 方法: 采用离体血管环灌流方法,观察芍药苷在含Ca²⁺ 或无Ca²⁺ K-H液孵育条件下对去甲肾上腺素(NA)引起的血管平滑肌收缩的影响;同法观察芍药苷对60 mmol ·L^-1 KC1引起的血管平滑肌收缩的影响;芍药苷对NA引起的依赖于细胞内钙和细胞外钙收缩反应的影响,以及加入L-NAME(N-硝基-L-精氨酸甲酯)后芍药苷舒张大鼠离体主动脉环效应的变化。 结果: 芍药苷呈浓度依赖性舒张含Ca²⁺ 和无Ca²⁺ K-H液中NA引起的血管收缩;对外钙收缩和内钙收缩均无抑制。芍药苷对KC1引起的血管平滑肌收缩也无抑制作用。L-NAME能够使芍药苷舒血管效应降低,芍药组的血管舒张程度与对照组有显著差别(P<0.05)。 结论: 芍药苷可呈内皮依赖性舒张血管平滑肌,其作用机制可能与该药促进NO合成释放有关,而与钙激活的钾通道以及抑制血管平滑肌细胞外钙内流和内钙释放无关。

Abstract:

Objective: To investigate the relaxative characteristics of paeoniflorin on thoracic aortic artery in rat and its mechanism. Method: We perfused the isolated rings and observed the response of NA-induced artery contraction to paeoniflorin under the Ca²⁺-contained and Ca²⁺-free bath solutions. In the same way the effects of paeoniflorin on the vascular smooth muscle were observed by adding KCl(60 mmol ·L^-1),and the effect on the contraction of the vascular smooth muscle depending on the intrace11ular calcium and extracellular calcium were also observed by adding NA. We also observed the effect of paeoniflorin on the contraction of rings induced by NA in the presence of L-NAME. Result: Peoniflorin relaxed rat aorta rings precontracted by NA in a dose-dependent manner.But had no effect on the aorta’s contraction induced by intracellular calcium and extracellular calcium as well as KCL(60 mmol ·L^-1),the relaxant effect could be attenuated by L-NAME.There was significant change in the group of paeoniflorin(P<0.05). Conclusion: The results indicate that paeoniflorin relaxes vascular smooth muscle in an endothelium-dependent manner. The mechanisms seem to be related with promoting synthesis and release of NO,but not for opening Ca²⁺ activated K⁺ channel as well as the inhibition of Ca²⁺ influx and release of Ca²⁺ from intracellular stores.