【摘要】 目的研究瘦素对大鼠消化间期移行性复合运动(MMC)和消化期胃运动的作用,并观察空腹MMC与餐后消化期胃运动的不同时程血中瘦素浓度的变化以及与胃动素变化的关系。方法50只Wister大鼠随机分为5组进行慢性实验。在胃体、胃窦和幽门浆膜植入应力传感器记录清醒大鼠胃运动。颈外静脉内置慢性静脉插管供注射药物及取血样品。血清瘦素和胃动素用放免法测定,进餐用标准试餐。结果空腹胃运动出现典型的消化间期MMC运动,分Ⅰ、Ⅱ、Ⅲ、Ⅳ时相,其Ⅲ相可传至幽门。进餐后胃运动呈持续有规则的蠕动性收缩的消化期运动。空腹MMC运动中血清瘦素的浓度分别为Ⅰ相(5．6±1．0)μg/L,Ⅱ相(11．4±2．1)μg/L,Ⅲ相(2．1±0．7)μg/L,显示MMCⅡ相瘦素浓度最高(P<0．01)。餐后消化期,血中瘦素浓度于进餐后3 min开始升高,至餐后10 min达到高峰(28．1±4．4)μg/L,随后30 min瘦素仍维持高水平(与餐前比较均P<0．01)。与瘦素相反,胃动素在MMCⅢ相时浓度最高,而餐后其浓度较低。静脉灌流瘦素(2．5μg·kg-1·10 min)可使空腹胃运动变为餐后胃体舒张、胃窦与幽门收缩的消化期运动类型。抗瘦素血清、阿托品及胆囊收缩素(CCK)-A受体阻断剂戊酰胺酸均可阻断瘦素对胃运动的作用。结论瘦素是启动空腹胃MMCⅡ相活动及餐后消化期运动的激素,其变化会导致与饱感有关的胃排空延迟。瘦素对胃运动的作用是通过胆碱能神经及CCK-A受体介导。更多还原

【Abstract】 Objective To observe the role of leptin on the regulation of inter-digestive migrating motor complex (MMC) and gastric motility of posprandial period, as well as the serum leptin level and its relationship with motilin during different fast and postprandial periods. Methods Strain gauges were implanted on the serosa of corpus, antrum and pylorus in 50 conscious Wistar rats to record the gastric motility activities. Canula was inserted in the external jugular vein for drug perfusion and blood sampling. The rats were randomly divided into 5 groups; (1) Group 1 to observe the relationship between the postprandial fasting MMC and MMC after feeding. MMC on the empty stomach was recorded, soon afterwards test meal was fed, then the gastric motility was recorded for 60 minutes. Blood samples were collected during the phasesⅠ,Ⅱ,Ⅲ, andⅣ, 3 minutes after feeding and then every 5 minutes to test the serum leptin and motilin. (2) Leptin group. After the recording of the first MMC, leptin was perfused during the second MMC to observe its effect on the stomach motility. (3) Anti-leptin serum group. During the second MMC, 5 minutes before feeding and 60 minutes after feeding, anti-leptin serum was perfused to observe the its effect on the postprandial stomach motility. (4) Leptin + atropine group. During the first MMC perfusion of atropine was followed by perfusion of leptin. and (5) leptin + cholecystokinin ( CCK) -A receptor blocker group. Perfusion of CCK- A receptor blocker was followed by perfusion of leptin. Serum leptin and motilin levels were measured by radioimmunoassay. Results Typical MMC with phaseⅠ,Ⅱ,Ⅲ, andⅣwas recorded in the fasting rats. The phaseⅢof antral MMC could migrate to the pylorus. During the postprandial period, the gastric motility patterns were persistent rhythmic peristaltic contractions. When the stomach was empty, the mean concentration of serum leptin was (5.6±1.0)μg/L, (11.4±2.1)μg/L, and (2.1±0.7)μg/L during the phaseⅠ,ⅡandⅢrespectively, being the highest in the phaseⅡ, significantly higher than those in the phaseⅠandⅢ(both P<0.01). During digestive period, the serum concentration of leptin began to increase 3 minutes after the meal and reached its peak of (28. 1±4.4)μg/L 10 minutes after the meal. The serum concentration of leptin remained on a high level till 30 minutes later (compared with that in the inter-digestive period, P <0.01). On the contrary, the serum concentration of motilin was the highest in the phaseⅢof MMC and the lowest in the digestive period. Intravenous infusion of leptin (2.5μg·kg-1·10 min) turned the inter-digestive pattern of gastric motility to digestive period pattern with corpus distension and contraction of antrum and pylorus. The effects of leptin on gastric motility were blocked by anti-leptin serum, atropine, and CCK-A receptor blocker loxiglumide. Conclusion Leptin is a hormone to promote the inter-digestive MMC phaseⅡand postprandial digestive motility activities of stomach, the concentration fluctuation of which will cause satiety related delay of gastric empty. The effect of leptin on gastric motility is mediated by cholinergic nerve and CCK-A receptors.更多还原