消化间期意识清醒狗胃左动脉及肠系膜上动脉血流变化的对比研究

摘要

目的 消化间期意识清醒狗发生周期性胃肠道移行性复合肌电运动(MMC).本研究选择支配胃肠的主要动脉-胃左动脉(LGA)和肠系膜上动脉(SMA),探讨MMC时LGA和SMA的血流动力学的变化.方法 选择5条意识清醒的狗,用超声波传输时间血流仪 (ultrasound transit-time blood flow meters) 持续测定LGA和SMA的血流.十二指肠的收缩期(phaseⅢ期)结束后30分钟,静脉内持续性滴注胃动素(12.5,25,50和100 pmol/kg/h)达30分钟.在另一个研究系列里,在有或无atropine (50 μg/kg followed by 25 μg/kg/h)的情况下,把溶解在1 ml生理盐水里的胃动素或 VIP(5,10,20,40和80 pmol/kg)1分钟内静脉推注.结果 胃动素 (12.5,25,50和100 pmol/kg/h)均诱导了LGA血流的增加,但对SMA、血压和心率没有影响.胃动素诱导的胃血管舒张作用有意义的大于VIP(Vasoactive intestinal polypeptide,血管活性肠肽)的同等剂量.结论 消化间期LGA血流与MMC同步发生周期性的变化,而SMA则持续平稳的维持在基础血流水平;胃动素是一个有效的而且是高度选择性的胃血管舒张剂,其在消化间期胃血流的调节中起着非常重要的作用.%Objective There was interdigestive periodic migrating myoelectric or motor complex of the upper gastrointestinal tract in conscious dogs .This study selected the left gastric (LGA) and superior mesenteric (SMA) arteries the main arteries dominating the gastrointestinal tract ,and investigated the hemodynamics of LGA and SMA during MMC .Methods Blood flow of the left gastric (LGA) and superior mesenteric (SMA) arteries were measured by ultrasound transit-time blood-flow meters in 5 conscious dogs . Moulin (12 .5 ,25 ,50 ,or 100 pmol?kg-1 ? h-1 ) was infused intravenously 30 minutes after the end of duodenal phase Ⅲ activities . In another series of studies ,motilin or VIP (5 ,10 ,20 ,40 ,and 80 pmol/kg ) dissolved in 1 ml of saline was injected intravenously over 1 minute with or without atropine (25 μg· kg-1-1·h-1 ) .Results Motilin (12 .5 ,25 ,50 ,and 100 pmol· kg-1·h-1) induced LGA blood flow increased ,without affecting the blood pressure ,heart rate ,and SMA blood flow .Motilin significantly induced larger gastric vasodilatation than the equivalent doses of VIP .Conclusion LGA blood flow showed periodic changes associated with interdigestive migrating myoelectric or motor complex of the gastrointestinal tract (MMC ) ,SMA blood flow remained unchanged during the contracting phase of the stomach and duodenum .Motilin has a potent and selective gastric vasodilator effect ,Motilin plays an important role in the regulation of interdigestive gastric blood flow in dogs .