[Motor coordination of the gastro-duodenal junction in the dog]

To record mechanical and electrical activities of the gastro-duodenal junction in dogs, before feeding after feeding and after drugs, four extraluminal strain-gauges and four bipolar electrodes were surgically implanted, one set on the pylorus, one in antrum and one on the duodenum. All the records were analyzed on a Nova 830 minicomputer for the frequency content of signals. The pylorus behaved primarily as an extension of the antrum in the sense that it had electrical and mechanical frequencies mostly in the range of 4-5 c/m, same as antrum. It did not show any relaxation in response to feeding. Both the duodenal electrodes showed a frequency component at antral frequency in both fasted and fed states. After feeding duodenal contractions, usually at a frequency of 18-20 c/m, were either inhibited or reduced and the duodenal mechanical activity showed a dominant frequency component at antral frequency. Pentagastrin (4 ug/kg/hr) induced a pattern similar to that after feedings, but it did not inhibit duodenal contractions at its inherent rate to the same extent as feeding. Antral frequencies were still present in the duodenal electrical records when atropine abolished all mechanical activity. This study shows objectively that during gastric emptying, duodenal contractions are coordinated with antral contractions.