Sphincter of Oddi cyclic motility. Effect of translocation of the papilla in opossums.

The role of myoneural continuity between the sphincter of Oddi and duodenum in coordinating sphincter cyclic motility and the duodenal migrating myoelectric complex was studied in conscious opossums. Five animals underwent implantation of the duodenal papilla into the jejunum. Myoelectric recording was obtained from the sphincter, duodenum, and jejunum in these animals and from 5 other animals as controls. The mean spike frequency of the sphincter of controls was 1.6 per min during phase I, 4.2 per min during phase II, 11.0 per min during phase III, and 3.6 per min during phase IV of the duodenal migrating myoelectric complex. After translocation of the papilla, the spike rates during phase II (2.2 per min) and phase III (2.8 per min) were lower than in controls (p less than 0.02), while those during phases I and IV remained unchanged. Feeding disrupted the migrating myoelectric complex and increased sphincter spike activity in both groups; however, the plateau frequency after feeding was lower after the translocation. These data suggest that the duodenum does not control cyclicity of sphincter motility but sphincter-duodenal intrinsic myoneural continuity is important in the increase in sphincter spike activity during phases II and III and after feeding.