Mechanism of pyloric contraction and relaxation after pylorus preserving gastrectomy

我们的研究旨在(1)正确测量幽门松弛，(2)确定内在和外在神经通路在幽门松弛中的作用。本研究的第二个目的是检查保幽门胃切除术（PPG）后的胃幽门运动，并确定迷走神经幽门支的影响。（方法）采用7组狗：5只狗胃肠道完整（对照组）；5只狗在幽门近端3cm处进行上颌窦横断并重新吻合（上颌窦横断组）；外源性幽门去神经组5只；5只犬行幽门外环去神经组（去神经组）上腔切开再吻合；5只犬行迷走神经截切术（迷走神经截切组）；5只PPG伴迷走神经幽门支保留；行幽门支迷走神经切除术（RPPG） 5只。用应变式力传感器记录清醒犬的胃幽门十二指肠运动。（结果）对照组和去神经支配组仅在消化间迁移运动复合体的第三期出现幽门松弛。在胃窦横断组、去神经横断组和迷走神经切开术组，在消化间期和餐后状态均未观察到幽门松弛。与对照组相比，这些组幽门收缩频率增加。无论是消化间期还是餐后状态，PPPG和RPPG对胃幽门十二指肠运动的影响均无显著差异。（结论）结果提示幽门在第三期发生松弛，以排出胃中未消化的颗粒，下行胃窦壁内通路在幽门松弛的控制中起重要作用。此外，PPG后胃幽门十二指肠运动不需要保留迷走神经幽门支。

Our study aimed at (1)measuring pyloric relaxation correctly and (2)determining the role of the intrinsic and extrinsic neural pathway in pyloric relaxation. Second aim of this study is to examine gastropyloric motility after pylorus-preserving gastrectomy (PPG) and to determine the influence of the pyloric branch of the vagus nerve. (Methods) Seven groups of dogs were used : five dogs had an intact gastrointestinal tract (control group) ; five dogs had transection and re-anastomosis of the antrum 3cm proximal to the pylorus (antral transection group) ; five dogs had extrinsic pyloric denervation (denervation group) ; five dogs had transection and re-anastomosis of the antrum with extrinsic pyloric ring denervation (transection with denervation group) ; five dogs had truncal vagotomy (vagotomy group) ; five dogs had PPG with preservation of the pyloric branch of the vagus (PPPG) ; and five dogs had PPG with resection of the pyloric branch of the vagus (RPPG). Gastropyloroduodenal motility was recorded by a strain-gauge force transducer in conscious dogs. (Results) In the control and denervation groups, pyloric relaxation was observed only during phase III of the interdigestive migrating motor complex. In the antral transection, transection with denervation, and vagotomy groups, pyloric relaxation was not observed in either the interdigestive or the postprandial state. The frequency of pyloric contractions increased in these groups in comparison with the control group. No significant differences were found between PPPG and RPPG in gastropyloroduodenal motility during either the interdigestive or postprandial state. (Conclusion) Results suggest that pyloric relaxation occurred during phase III to expel undigested particles from the stomach and that descending antral intramural pathways play an important role in the control of pyloric relaxation. Furthermore, it is not necessary to preserve the pyloric branch of the vagus for gastropyloroduodenal motility after PPG.