辣椒素对大鼠肠系膜阻力血管的舒张作用及其机制

目的：观测辣椒素（capsaicin，CAP）对大鼠肠系膜阻力血管的舒张作用，探讨其可能机制。 方法：雄性Sprague-Dawley大鼠，取肠系膜动脉三级分支约2 mm长血管环，置于DMT 610M系统，记录张力变化。 结果：CAP（10^-9~10^-5 mol/L）对苯肾上腺素（PE）预收缩的内皮完整血管和去内皮血管产生浓度依赖性的舒张作用，其中内皮完整组的血管舒张作用比去内皮组更明显，两者相比CAP在10^-7~10^-5 mol/L时，差异有统计学意义（P<0.01）。该舒张作用可被一氧化氮合酶抑制剂L-NAME和CGRP竞争性阻滞剂CGRP8-37阻断。CGRP（10^-10~3×10^-8 mol/L）对PE预收缩的内皮完整血管和去内皮血管产生浓度依赖性的舒张作用，其中内皮完整组的血管舒张作用比去内皮组更明显，两者相比CGRP在3×10^-9~3×10^-8 mol/L时，差异有统计学意义（P<0.05）。P物质对PE预收缩的内皮完整血管无舒张作用。 结论：CAP对大鼠肠系膜阻力动脉具有部分内皮依赖性舒张作用，该作用机制与其促进内皮一氧化氮合酶（NOS）途径有关；CAP的非内皮依赖性舒张血管效应与CGRP释放有关。

Vasodilating effect of capsaicin on rat mesenteric artery and its mechanism

Objective： To investigate the vasodilating effect of capsaicin(CAP) on rat mesenteric artery and its mechanism. Methods： The third branch of the superior mesenteric artery in male Sprague-Dawley rat(250-350 g) was excised，the periadventitial fat and connective tissue were removed and the mesenteric artery was dissected into 2 mm rings.Each ring was placed in a 5 ml organ bath of DMT 610M system and the tension was recorded. Results： CAP(10^-9-10^-5 mol/L) relaxed endothelium-intact and endothelium-denuded mesenteric artery pre-constricted by phenylephrine(10^-5 mol/L)，and the vasodilation in endothelium-intact mesenteric artery was stronger than that in endothelium-denuded one.Pretreatment with either L-NAME(3×10^-4 mol/L)，an inhibitor of nitric oxide synthase(NOS)， or CGRP8-37(2×10^-6 mol/L)，an antagonist of calcitonin gene-related peptide(CGRP)，for 30 min significantly attenuated the relaxation of endothelium-intact mesenteric artery induced by CAP.CGRP(10^-10-3×10^-8 mol/L) relaxed endothelium-intact and endothelium-denuded mesenteric artery pre-constricted by phenylephrine，and the vasodilation in endothelium-intact mesenteric artery was stronger than that in endothelium-denuded one.Substance P did not relax the mesenteric artery pre-constricted by phenylephrine. Conclusions： CAP has partial endothelium-dependent relaxation effect on rat mesenteric artery，which may be mediated by activating the endothelial NOS-NO pathway.The endothelium-independent relaxation in rat mesenteric artery induced by CAP may be mediated by CGRP.