P2X受体对豚鼠胃窦环行肌自发性收缩运动的影响  

Effect of P2X receptor on the spontaneous contraction of gastric antral circular muscle in guinea pigs

作　　者：黄旭[1] 张扬[1] 高玲[1] 赵鹏[1] 韩燕飞[1] 许文燮[1] 

机构地区：[1]上海交通大学医学院生理学教研室,上海市200240

出　　处：《世界华人消化杂志》2007年第11期1185-1190,共6页World Chinese Journal of Digestology

基　　金：国家自然科学基金;No.30360031~~

摘　　要：目的:探讨P2X受体激动剂α,β-methylene ATP (α,β-MeATP)对豚鼠胃窦环行肌运动的影响及其离子通道机制.方法:采用EWG/B豚鼠,制备去黏膜胃窦环行肌条(10×1.5 mm),并将其固定于恒温灌流槽内(37℃),用碳酸氢钠缓冲液连续灌流并通氧(950 mL/L O_2,50 mL/L CO_2).利用SMUP-E生物信号处理系统记录胃窦平滑肌自发性收缩活动,Ⅱ型胶原酶消化法分离豚鼠胃窦环行肌单细胞,传统全细胞膜片钳技术记录急性分离的胃窦平滑肌细胞膜电位和离子电流,包括钙激活钾电流、延迟整流型钾电流及电压依赖性钙电流.结果:嘌呤能P2X受体激动剂α,β-MeATP明显抑制豚鼠胃窦环行肌自发性收缩,并有明显的量效倚赖关系:5,10,20,40,100μmol/Lα,β-MeATP作用下,环行肌收缩幅度分别由对照组的100%下降到90%±2%.81%±4%,68%±4%,59%±7%和29%±4%(P<0.05).用神经阻断剂Tetrodotoxin (TTX)预处理后,α,β-MeATP对胃窦环行肌自发性收缩的抑制作用仍不受影响;在传统全细胞膜片钳电流钳模式下,500μmol/Lα,β-MeATP不影响细胞膜电位,也对两种外向钾电流,即延迟整流型钾电流和钙激活钾电流没有影响;不同浓度的α,β-MeATP对电压依赖性钙电流没有影响.结论:P2X受体激动剂抑制豚鼠胃窦环行肌自发性收缩,其作用机制不依赖内在神经,也不依赖细胞膜离子通道以及膜电位改变.AIM： To investigate the effect of alpha, betamethylene ATP （α, β-MeATP） on gastric smooth muscle motility and its ionic channel mechanism in guinea pigs. METHODS： EWG/B guinea pig was used in this study. Gastric antral smooth muscle strips （10 × 1.5 mm） were prepared and then fixed in the organ bath system （37℃） which were perfused with sodium bicarbonate buffer solution and aerated （950 mL/L 02, 50 mL/L CO2）. The spontaneous contraction of gastric antral circular muscle was recorded by SMUP-E bioelectric signal-processing system. The single gastric myocyte was dispersed with type Ⅱ collagenase, and the ionic current and membrane potential were recorded using whole-cell patch clamp technique in freshly dispersed smooth muscle cells, including calcium-activated potassium current, delayed rectifier potassium current, and voltage-dependent calcium current. RESULTS： α, β-MeATP, a P2X receptor agonist, significantly inhibited the spontaneous contraction of gastric antral circular muscle in a dosedependent manner, and the contraction extent were decreased from 100% to 90% ± 2%, 81% ± 4%, 68% ± 4%, 59% ± 7% and 29% ± 4% when α, β-MeATP was used at the concentrations of 5, 10, 20, 40 and 100μmol/L （P 〈 0.05）. Tetrodotoxin, a blocker of neural transduction, did not affect α, β-MeATP-induced inhibition of the spontaneous contraction. Under conventional whole-cell patch clamp configuration, 500 μmol/ L α,β-MeATP did not change membrane potential and affect either delayed rectifier or calciumactivated potassium currents. 500μmol/L and 1 mmol/L α,β-MeATP did not influence voltage-dependent calcium currents either. CONCLUSION： α, β-MeATP, a P2X receptor agonist, induces relaxation of gastric antral circular muscle and this effect depend on neither the enteric nerve nor hyperpolarizing membrane potential as well as changing ionic channel activity in guinea pig.

关 键 词：α β-MeATP P2X嘌呤受体 胃窦环行肌 

分 类 号：R573[医药卫生—消化系统]