胃泌素对家兔下食管括约肌及食管跨粘膜电位的影响

Effects of gastrin on lower esophageal sphincter and esophageal transmucosal potential difference in rabbits

观察了静脉注射(ⅳ)不同剂量的五肽胃泌素(Pentagastrin,G5)对家兔下食管括约肌压力(Lower esophageal sphincter pressure,LESP)及食管跨粘膜电位(Transmucosal potential difference,PD)的影响。结果显示:ⅳGS(10μg/km)可引起LESP迅速升高和LES功能长度(Lower esophageal sphincter length,LESL)延长(P<0.01),10min左右恢复到基础水平。ⅳG5(5μg/kg)即可导致LES部位和食管中下段PD明显下降,但上段食管PD无变化。可见ⅳG5既能显著地影响食管的神经肌肉功能LESP,也能影响食管的粘膜功能PD。此外,大剂量阿托品(1mg/kg)不能完全阻断G5(20μg/kg)对LESP的影响(P<0.05),提示ⅳG5对LES的升压作用主要是它直接作用于LES的结果。

The pressure of the lower esophageal sphincter (LESP) and the esophageal transmucosal potential difference(PD) in healthy rabbits were measured with a rapid pull-through technique. After the establishment of the baseline manometry and the PD values, the effects of different doses of pentagastrin (G5) given an intravenous (iv) bolus injection on the LESP and the esophageal PD were observed. The results showed that 10 μg/kg iv bolus injection of G5 produced immediate increases (P<0.01) in the sphincter pressure and its functional length, which then returned to the basal level within about ten minutes. G5 (5μg/kg) dramatically reduced PD in the distal and middle thirds of the esophagus, but didn't alter that in the proximal esophagus. Based on these findings, it was concluded that the administration of G5 significantly influences both esophageal neuromuscular (LESP) function and the mucosal (PD) function. Furthermore, the response of the LESP to G5 was not blocked completely by a high dose (1mg/kg) of atropine, which suggests that the stimulating effect of G5 might mainly be due to the direct action of G5 on the LES.