论文部分内容阅读
本文研究槲皮素对豚鼠结肠的收缩性及对结肠平滑肌细胞电压依赖性钙通道的影响,以探讨槲皮素舒张结肠平滑肌的机制。实验中用张力换能器记录结肠肌条的收缩,用木瓜蛋白酶分离近端结肠平滑肌细胞,全细胞膜片钳技术记录L型钡电流(IBa,L,为了改善钙衰减,细胞外液中用钡离子代替钙离子)。实验观察到,槲皮素浓度依赖性地抑制结肠收缩,且能拮抗乙酰胆碱和新斯的明(neostigmine)对结肠的收缩作用。吲哚美辛[环氧合酶(cyclooxygenase,COX)抑制剂]和亚甲蓝[鸟苷酸环化酶(guanylate cyclase,GC)抑制剂]可以拮抗槲皮素舒张结肠平滑肌的作用。槲皮素浓度[EC50=(7.59±0.38)μmol/L]和电压依赖性地增大结肠平滑肌细胞的IBa,L,使电流-电压曲线的最大激活电压向去极化方向移动10mV,但不改变IBa,L的阈电位。槲皮素向去极化方向移动稳态失活曲线约3.75mV,但不改变激活曲线和失活曲线的斜率。H-89[蛋白激酶A(protein kinase A,PKA)抑制剂]能够阻断槲皮素增大IBa,L的作用,而cAMP能够增强槲皮素增大IBa,L的作用。这些结果说明槲皮素通过PKA途径增大IBa,L。槲皮素通过GC和COX途径以及拮抗乙酰胆碱的作用来抑制结肠的收缩,而其增大钙离子内流的作用不足以抵消上述的抑制作用,从而表现为槲皮素对结肠的舒张作用。
This study was to investigate the effect of quercetin on the contractility of the colon of guinea pigs and the voltage-dependent calcium channel of colonic smooth muscle cells, in order to investigate the mechanism of quercetin relaxant colon smooth muscle. In the experiment, the contraction of the colon muscle strips was recorded with a tension transducer, the proximal colonic smooth muscle cells were isolated with papain, and the whole cell patch clamp technique was used to record the L-type baboon current (IBa, L, for improving the calcium attenuation, the extracellular fluid was used Ions instead of calcium ions). It has been experimentally observed that quercetin inhibits the contraction of the colon in a concentration-dependent manner and antagonizes the contractile action of acetylcholine and neostigmine on the colon. Indomethacin (cyclooxygenase (COX) inhibitors) and methylene blue (guanylate cyclase (GC) inhibitors) can antagonize the effect of quercetin on the relaxation of colonic smooth muscle. Quercetin concentration [EC50 = (7.59±0.38) μmol/L] and voltage-dependent increase of IBa, L in the colonic smooth muscle cells, so that the maximum activation voltage of the current-voltage curve was shifted by 10 mV in the direction of depolarization, but not Change the threshold of IBa,L. Quercetin shifted the steady-state inactivation curve by approximately 3.75 mV toward depolarization, but did not change the slope of the activation and inactivation curves. H-89 [protein kinase A (PKA) inhibitor] can block the effect of quercetin on IBa, L, and cAMP can increase the effect of quercetin on IBa, L. These results indicate that quercetin increases IBa,L through the PKA pathway. Quercetin inhibits the contraction of the colon by GC and COX pathways and antagonizes the action of acetylcholine, and its effect of increasing the influx of calcium ions is not sufficient to counteract the above-mentioned inhibitory effect, thereby manifesting the relaxation effect of quercetin on the colon.