生长抑素对应激下胆囊收缩素介导的胆汁反流的抑制作用  

Inhibitory effects of somatostatin on cholecystokinin octapeptidemediated bile regurgitation under stress:ionic and molecular mechanisms

作　　者：司新敏[1] 黄磊[2] 施瑞华[1] 罗和生[3] 

机构地区：[1]南京医科大学第一附属医院消化内科,江苏省南京市210029 [2]南京医科大学附属南京市儿童医院普外科,江苏省南京市210008 [3]武汉大学人民医院消化内科,湖北省武汉市430060

出　　处：《世界华人消化杂志》2010年第24期2521-2527,共7页World Chinese Journal of Digestology

基　　金：国家自然科学基金资助项目;No.30900666~~

摘　　要：目的:探讨应激下胃肠肽-八肽胆囊收缩素(CCK-8S)、生长抑素(SS)的变化,以及二者在应激所致胆汁反流中的相互作用和相关机制.方法:(1)放射免疫方法检测血浆CCK-8S和SS水平,并与正常对照组进行比较;(2)多导生理记录仪记录胃窦离体肌条在不同条件下的收缩活动;(3)免疫印迹法和免疫沉淀法检测胃窦平滑肌细胞(SMC)三型1,4,5-三磷酸肌醇受体(InsP3R3)磷酸化水平;(4)Fura-3/AM标记胃窦SMC,观察硫化CCK-8S和SS对胞内钙离子浓度([Ca2+]i)的影响;(5)全细胞膜片钳检测胃窦SMC的L-型电压门控钙通道电流(ICa-L)的变化情况.结果:(1)应激各时段血浆CCK-8S浓度和胃内胆汁反流水平明显增强(均P<0.01),以应激结束后1-2h最为显著,而血浆SS浓度则呈下降趋势(均P<0.05);(2)CCK-8S作用下胃窦和幽门纵行及环形肌条收缩幅值、频率改变明显(均P<0.01),SS作用相反且能阻断CCK的增强效应;(3)CCK-8S显著增强胃窦平滑肌细胞[Ca2+]i荧光强度和ICa-L(均P<0.01),SS作用相反且能阻断CCK的增强效应;(4)SS作用下CCK-8S上调的InsP3R3磷酸化水平可被显著增强.结论:应激下胆汁反流及其介导的损伤效应与CCK和SS变化介导的胃动力紊乱密切相关.CCK-8S通过增强胞内钙释放和促进外钙内流增强胃窦收缩,该效应可被SS所阻断,二者在应激所致的胃动力紊乱中起到重要作用.AIM：To investigate the ionic and molecular mechanisms underlying the effects of changes in plasma cholecystokinin octapeptide（CCK8S）and somatostatin（SS）on stress-induced bile regurgitation in rats.METHODS：The changes in plasma CCK-8S,SS and intragastric bile concentration under stressful condition were measured by radioimmunoassay（RIA）.The contractile response of gastric antral smooth strips isolated from healthy adult rats was recorded by poly physiography.The regulatory effect of protein kinase C（PKC）on the phosphorylation of type 3 inositol 1,4,5-triphosphate receptor（InsP3R3）in gastric smooth muscle cells（SMC）was determined by immunoprecipitation.The changes in intracellular calcium fluorescence intensity（FI）of SMC（presented as [Ca2＋]i）were analyzed by laser scanning confocal microscopy.L-type voltage-dependent calcium currents（ICa-L）of SMC were recorded by the patch-clamp technique.RESULTS：Both plasma CCK-8S level and gastric bile concentration significantly increased during the stress period and reached the peak at 2 h after stress,while reverse effect was observed in plasma SS level.Respective addition of CCK-8S and SS caused a rapid,sustained,concentration-dependent increase and decrease in muscle contraction of gastric antral strips,and CCK-8S-induced increase in the contractile response could be signifi cantly blocked by administration of nifedipine or SS.Similar results were obtained for the changes in FI and ICa-L of SMC.Pretreatment with SS signifi cantly increased CCK-8S-promoted phosphorylation of InsP3R3 in SMC.CONCLUSION：Gastric mucosal damage induced by bile regurgitation under stressful condition is closely associated with gastric antral dysmotility evoked by the changes in CCK-8S and SS.CCK-8S-enhanced gastric antral contraction depends on the release of intracellular calcium stores and the influx of extracellular calcium via L-type voltage-dependent calcium channels,and can be blocked with SS,suggesting that both CCK-8S and SS play important roles

关 键 词：应激 胆汁反流 胆囊收缩素 生长抑素 胃动力 

分 类 号：R573.1[医药卫生—消化系统]