Duodenal intramural nerves in control of pyloric motility and gastric emptying.

We have investigated the role of ascending duodenal intramural nerves in the control of isolated pyloric pressure waves (IPPW) and liquid gastric emptying. In six pigs, the proximal duodenum was transected to interrupt intramural nerves. A further six pigs had a sham operation. Four weeks after operation, motility of the antrum, pylorus, and duodenum was recorded by side holes and a sleeve sensor. Gastric emptying of a 1,000-ml test meal was significantly more rapid in duodenum-transected animals (P less than 0.0001) during intraduodenal infusion of each of isosmolar dextrose (424 ml emptied), fatty acid (335 ml), and amino acids (396 ml) than in duodenum-intact animals (dextrose: 128 ml; fatty acid: 57 ml; amino acids: 192 ml). Associated with this, in duodenum-transected animals infusion of each of isosmolar dextrose, fatty acid, amino acids, and hyperosmolar saline failed to produce the stimulation of IPPW seen in duodenum-intact animals. In both duodenum-intact and -transected animals, supramaximal stimulation by intraduodenal infusion of 25% dextrose slowed gastric emptying and stimulated IPPW. Ascending duodenal intramural nerves are a major physiological pathway for nutrient- and osmolar-stimulated feedback control of pyloric motility and gastric emptying.