Pyloric opening and closure evaluated by means of strain gauge force transducers

Recently, gastrointestinal motility research and various studies to measure motility have been conducted. However, it is not easy to measure the pyloric sphincter motility, especially its open and closed motility. There are few reports on the opening and closed motility of the pyloric ring. In this study, I examined the pyloric motility with strain gauge force transducers (SGTs). SGTs were implanted onto the antrum, pyloric ring and duodenum of a dog. In order to clarify the relationship between the opening and closed motility of the pylorus and SGTs recordings, the pyloric ring was observed with a gastrofiberscope while measurements were taken using the SGTs in anesthetized dogs. In addition, the pyloric ring was extended mechanically with a balloon and measurement were taken using the SGTs. In conscious dogs, the natural gastropyloroduodenal motility was recorded. Then, cisapride, erythromycin, and Leu13-motilin were administered in the interdigestive state and the motility was recorded. The pyloric opening and closed motility could be monitored using SGTs. The pyloric ring opened when the pyloric motility recorded using the SGTs showed a negative deflection. In addition, in phase III, when intense contraction of the antrum was observed, relaxation and opening of the pyloric ring could be observed. Erythromycin and Leu13-motilin induced phase III-like motility and relaxation of the pyloric ring. However, in cisapride-induced motility, relaxation of the pyloric ring was not observed. The pyloric ring opening and closed motility can be monitored using SGTs and this method is effective for the evaluation of the pyloric function.