槲皮素对豚鼠结肠平滑肌收缩性和钙通道的影响(英文)  

Effect of quercetin on colon contractility and L-type Ca^(2+) channels in colon smooth muscle of guinea-pig

作　　者：黄伟锋[1] 欧阳守[1] 李世英[1] 林燕飞[1] 欧阳晖[1] 张慧[1] 卢春敬 

机构地区：[1]厦门市医药研究所,厦门361003 [2]厦门市妇幼保健院输血科,厦门361003

出　　处：《生理学报》2009年第6期567-576,共10页Acta Physiologica Sinica

基　　金：supported by the Key Project of Department of Science and Technology of Fujian Province, China (No. 2009D026);the Science Foundation of Health Bureau of Xiamen Municipality (No. WZK21, 3502z20077077);the Science Foundation of Health Department of Fujian Province, China (No. 2007-1-45)

摘　　要：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。The aim of the present study was to investigate the effects of quercetin on colon contractility and voltage-dependent Ca（2＋） channels in the single smooth muscle cell isolated from the proximal colon of guinea-pig and to clarify whether its effect on L-type Ca（2＋） current （I（Ca,L）） would be related to its myorelaxing properties. Colon smooth muscle strips were used to take contractile tension recordings. Smooth muscle cells were freshly isolated from the proximal colon of guinea-pig by means of papain treatment. I（Ba,L） （barium instead of calcium as current carrier） was measured by using whole-cell patch-clamp techniques. The results showed that quercetin relaxed colon muscle strips in a concentration-dependent manner and antagonized the contractile effect of acetylcholine and neostigmine. Preincubation with indomethcin [cyclooxygenase （COX） inhibitor] and methylene blue [guanylate cyclase （GC） inhibitor] significantly attenuated the relaxing effect of quercetin, respectively. Quercetin increased I（Ba,L） in a concentration- [EC（50）= （7.59＋/-0.38） mumol/L] and voltage-dependent pattern, and shifted the maximum of the current-voltage curve by 10 mV in the depolarizing direction without modifying the threshold potential for Ca（2＋） influx. Quercetin shifted the steady-state inactivation curve toward more positive potentials by approximately 3.75 mV without affecting the slope of activation and inactivation curve. H-89 （PKA inhibitor） abolished quercetin-induced I（Ba,L） increase, while cAMP enhanced the quercetin-induced I（Ba,L） increase. The patch-clamp results proved that quercetin increased I（Ba,L） via PKA pathway. It is therefore suggested that the relaxing effect of quercetin attributes to the interaction of GC and COX stimulation, as well as the antagonism effect on acetylcholine, which hierarchically prevails over the increase in the Ca（2＋） influx to be expected from I（Ca,L） stimulation.

关 键 词：槲皮素 结肠 L-型钙通道 豚鼠 

分 类 号：R285.5[医药卫生—中药学]