禁食大鼠胃肠肌电活动和胃动素与熊去氧胆酸的关系

目的　研究大鼠禁食状态下不同起源的胃肠移行性复合肌电活动 (MMC)的特征异同以及胃动素 (MTL)和熊去氧胆酸 (UDCA)对不同起源MMC的作用。方法　 2 4只大鼠被随机分为两组。在胃窦、十二指肠及空肠慢性埋置银丝电极。术后 7d在大鼠清醒、禁食状态下实验。第一组静脉注入合成猪MTL ,第二组给予UDCA灌胃。记录给药前 1h至给药后 2h胃肠肌电活动。结果　实验共观察到 6 8个正常的MMC波形 ,其中 33%起源于胃窦 ,6 7%起源于十二指肠。起源于胃窦的MMC波的周期和Ⅲ期的时程明显长于十二指肠起源的MMC波的相应参数。静脉注射合成猪MTL可引发起源于胃窦的不成熟Ⅲ相波 ,UDCA灌胃可使起源于十二指肠的MMC波周期缩短 ,Ⅲ期时程延长。结论　禁食大鼠MMC波可起源于胃窦和十二指肠 ,不同起源MMC波形特征不同。MTL和UDCA可分别影响禁食状态下不同起源的胃肠肌电活动。

The relationship between the gastrointestinal myoelectrical activity and motilin and ursodeoxycholic acid in fasting rats

Objective To investigate the different characteristics of gastrointestinal migrating myoelectrical complex (MMC) of different origin in fasting state and the effects of motilin (MTL) and ursodeoxycholic acid (UDCA) on the MMC of the gastrointestinal tract of different origin in rats. Methods Three bipolar silver electrodes were chronically implanted on the antrum, duodenum and jejunum. Seven days later twenty-four experimental rats were divided into two groups. One group were injected with porcine MTL via sublingual vein, while the other group was perfused with UDCA into the stomach. The gastrointestinal myoelectrical activity was recorded one hour before and two hours after the test substances infusions on these conscious fasting rats. Results Among the total sixty-eight MMCs recorded in fasting rats under control, 67% started in the duodenum, and 33% started in the antrum. The MMC cycle duration and duration of phase Ⅲ of antral origin were longer than those of duodenal origin. Administration of porcine MTL could induce a premature antral phase Ⅲ of antral origin. However, perfusion into the stomach with UDCA resulted in a shorter MMC cycle duration and longer duration of phase Ⅲ of duodenal origin. Conclusion In fasting rats, MMC may originate from the antrum and duodenum, respectively. The different characteristics of MMC of different origin may contribute to the large variations within subjects. Pocrine MTL and UDCA can affect the MMC of different origin of the gastrointestinal tract in fasting state.