Myoelectric Activity of the Diverted Antroduodenum in the Dog 1

Abstract

Electrodes were chronically implanted on the gastric antrum and the orad duodenum of four dogs. After implantation, fasted and fed state myoelectric activity was monitored. After control testing, the stomach was bisected at the orad antral margin and the antrum was closed. Bowel continuity was restored with gastrojejunostomy. Extrinsic nerves of the antroduodenal segment were maintained. After surgery, fasted and fed state myoelectric activity were reassessed. Surgical diversion of the antroduodenum was previously shown to result in chronic hypergastrinemia of a postprandial magnitude. It also resulted in separation of the antrum from its myoelectric pacemaker in the orad corpus, and a chronic absence of digesta from the diverted segment. In the present experiments both the antrum and duodenum exhibited unchanged migrating myoelectric complex periods. In addition, the duodenal BER frequency was unchanged. In contrast, the antral BER frequency was reduced by half. The percentage of antral and duodenal BER superimposed with spike potentials in response to liquid or solid meals was unchanged postoperatively despite the absence of food in the diverted segment, and despite the absence of postprandially elevated gastrin. We conclude that a hormone other than gastrin, and/or a neurally conducted impulse generated by the physical presence of the food in the gastric remnant, contributed to the postprandial generation of spike potentials in the diverted antroduodenum.