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目的 在低压舱中模拟不同高度状态 ,观察狗消化间期胃肠移行性复合运动 (MMC)和血浆胃动素的变化。 方法 应用低顺应性毛细管水灌注消化道腔内测压系统记录清醒狗胃和十二指肠的收缩活动。先在低压舱海平面记录狗正常 MMC,然后分别在 MMC 相初期和后期模拟升至 30 0 0 m和 5 0 0 0 m高度停留 1h,记录 MMC的变化 .并在不同时间点抽取静脉血测定血浆胃动素浓度。 结果 30 0 0 m高度对 MMC无明显影响 ,但在 5 0 0 0 m高度发现 :1狗 MMC周期时间延长 ,主要是 相时间延长 , 相时间缩短 ;2在 MMC 相初期模拟升空 ,胃窦和十二指肠 MMC 相收缩振幅和动力指数明显低于海平面对照 (P<0 .0 5 ,P<0 .0 1) ,MMC 相被抑制 ;3在 MMC 相后期模拟升至 5 0 0 0 m高度 ,MMC 相仍能出现 ,但其收缩振幅和动力指数明显降低 (P<0 .0 5 ,P<0 .0 1) ;4在海平面 ,血浆胃动素随 MMC周期出现周期性波动 ,其浓度在 MMC 相时最高 ,在MMC 相时最低。在 MMC 相后期升至 5 0 0 0 m高度 ,虽有血浆胃动素高峰 ,但胃动素高峰浓度明显低于海平面对照 (P<0 .0 5 ) ;而在 MMC 相初期升至 5 0 0 0 m 高度 ,则血浆胃动素浓度无明显高峰出现。 结论 急性暴露低压低氧干扰了胃肠 MMC的活动 ,血浆胃动素释放减少可能介导了胃肠抑制作用。
Objective To simulate different height states in the low-pressure cabin and observe the changes of gastrointestinal migrating compound exercise (MMC) and plasma motilin in the digestive tract of dogs. Methods The contractile activity of awake dogs’ stomach and duodenum was recorded by low conformity capillary water perfusion intraluminal manometry system. First, the normal MMC was recorded at the sea level of the low-pressure cabin, and then simulated to 300 000 in the early and late stages of the MMC phase and 1 h in the altitude of 500 meters, respectively. The change of MMC was recorded, and venous blood was taken at different time points Plasma motilin concentration. Results There was no significant effect on MMC at 30 000 m height. However, at the height of 500 m, the duration of MMC cycle was prolonged and the phase time was shortened. 2 During the initial phase of MMC MMC, the gastric antrum (P <0.05, P <0.01), MMC phase was inhibited; 3 in the late MMC phase simulation increased to 50 000 However, the amplitude and dynamic index of contraction were significantly decreased (P <0.05, P <0.01). 4 At sea level, plasma motilin appeared periodically fluctuating with MMC cycles , The highest concentration in the MMC phase, the lowest in the MMC phase. However, the peak concentration of motilin was significantly lower than that of the sea level control (P <0.05) at the later stage of MMC phase but reached the level of 50% at the early phase of MMC 0 0 m height, the plasma motilin concentration no significant peak appears. Conclusions Acute hypobaric hypoxia may interfere with the activity of gastrointestinal MMC. The decrease of plasma motilin may mediate the inhibition of gastrointestinal.