甲烷对大鼠近端结肠动力的影响及离子通道机制  

Effects of methane on proximal colon motility of rats and ion channel mechanisms

作　　者：刘颖[2] 罗和生[1] 梁成柏[1] 谭韡[1] 夏虹[1] 徐文娟[1] 

机构地区：[1]武汉大学人民医院消化科430060 [2]桂林医学院附属医院消化科

出　　处：《中华医学杂志》2013年第6期459-463,共5页National Medical Journal of China

基　　金：国家自然科学基金（81070297）

摘　　要：目的探讨甲烷对大鼠近端结肠动力的影响及离子通道机制。方法取大鼠近端结肠制备纵行肌条及环形肌条；张力换能器及多通道生理信号采集处理系统记录甲烷对肌条自发性收缩的影响，观察纵行肌条经河豚毒素或N-硝基-L-精氨酸（L-NAME）预处理后甲烷对其自发性收缩的影响；消化分离近端结肠平滑肌细胞，运用全细胞膜片钳技术检测甲烷作用前后平滑肌细胞电压依赖性钾电流（IKv）及大电导钙依赖钾电流（IBKca）的变化。结果甲烷作用下纵行肌收缩幅度由（1．12±0．27）g降为（0．99±0．31）g（n=19，P=0．013），但其中部分肌条（n=6）经甲烷作用后收缩幅度无变化；经河豚毒素或L．NAME预处理后甲烷对纵行肌抑制效应仍然存在；甲烷对纵行肌收缩周期及环形肌的自发性收缩无影响。在阶跃刺激为＋60mV时，3％甲烷溶液作用后IKca电流密度由（13．3±1．0）pA／pF增加为（18．5±1．4）pA／pF（n=11，P=0．001）；不同浓度甲烷溶液对IBKca无明显影响（均P〉0．05）。结论甲烷可能通过开放平滑肌细胞电压依赖性钾通道、增加IKca进而抑制近端结肠纵行肌收缩。Objective To explore the effects of methane on proximal colon motility and elucidate its ion channel mechanisms. Methods The circular muscle and longitudinal muscle strips of proximal colon were isolated from rats. An isometric force transducer and a biology signal collection system were employed to observe the effects of methane on spontaneous contractile activity of muscle strips. The effects of methane on longitudinal muscle strips were observed after pre-treatment of these strips with tetrodotoxin （TTX） or N- nitro-L-arginine methylester （L-NAME）. Single cell of colonic smooth muscle was isolated by collagenase and then whole-cell patch clamp technique was used to record voltage dependent potassium current （ IKv ） and large conductance Ca2 ＋ -activated K ＋ current （ IBKca ） in the absence or presence of methane. Results Methane significantly attenuated the contractile amplitude of longitudinal muscle strips （from（ 1.12-＋ 0. 27 ） to （0. 99-＋ 0. 31 ）g, n = 19, P = 0. 013 ） whereas there were no changes in some longitudinal muscle strips （ n = 6） in the presence of methane. The inhibitory effect of methane persisted after the pre-treatment of longitudinal muscle strips with T13（ or L-NAME. Methane had no effects on the contractile cycle time of longitudinal muscle strips and contractile activity of circular muscle strips. And 3% methane solution significantly increased the density of IKv （ from（ 13.3 -＋ 1.0） pA/pF to（ 18. 5 -＋ 1.4） pA/pF, at ＋ 60 mV, n =11, P= 0. 001 ） versus the control group whereas methane had no effect on IBKca （all P 〉 0. 05 ）. Conclusion Methane can inhibit contractile activity of proximal colonic longitudinal muscle by activating voltage dependent potassium channel and increasing IKv.

关 键 词：甲烷 膜片钳术 电压依赖性钾通道 

分 类 号：R363[医药卫生—病理学]