title: Mechanisms governing the biphasic pattern of gastric emptying after truncal vagotomy and pyloroplasty.
abstract: The pattern of gastric emptying after truncal vagotomy and drainage is usually biphasic. An early rapid phase is followed by a characteristically abrupt transition to slow emptying. The mechanisms responsible for this pattern were studied in six dogs with truncal vagotomy and pyloroplasty, fitted with a proximal duodenal cannula. Gastric emptying was measured using gamma camera imaging of a radiolabelled 15% dextrose test meal. Sixty one hour studies were done using five designs. (1) With the cannula closed gastric emptying was initially rapid, followed by stasis (emptying at 15 min - 32% (5.3), 60 min - 34% (4.8); mean (SE)). (2) With the cannula open emptying was very rapid (15 min - 76% (4.2) p less than 0.001, 60 min - 88% (2.6) p less than 0.001 ANOVA). (3) Distal duodenal instillation of isotonic saline, at a rate equivalent to gastric emptying with the cannula closed, did not retard this rapid emptying (15 min - 78% (10.6), 60 min - 90% (5.4)). (4) With duodenal instillation of 15% dextrose, gastric emptying remained faster than in studies without diversion (15 min - 50% (7.0) NS, 60 min - 65% (6.8) p less than 0.01), but was slower than during diversion alone (p less than 0.05). (5) Finally, duodenal instillation of 15% dextrose before administration of the test meal produced slower initial emptying without subsequent stasis (15 min - 24% (4.5), 60 min - 47% (10.6)), although the amounts emptied were not significantly different from those with the cannula closed. These results indicate that after truncal vagotomy and pyloroplasty small bowel resistances play a significant role in controlling gastric emptying. Osmoreceptor responses persist after truncal vagotomy, but sympathetic inhibitory responses to small bowel distension are not involved in the regulatory process.
authors.affiliation: University Department of Surgery, Royal Liverpool Hospital.
authors.forename: N J
authors.initials: NJ
authors.lastname: Parr
authors.forename: S
authors.initials: S
authors.lastname: Grime
authors.forename: M
authors.initials: M
authors.lastname: Critchley
authors.forename: J N
authors.initials: JN
authors.lastname: Baxter
authors.forename: C R
authors.initials: CR
authors.lastname: Mackie
mesh_terms: D000818:Animals; D004285:Dogs; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D011708:Pylorus / Q000601:surgery*; D013997:Time Factors; D015167:Vagotomy, Truncal
chemical_list: D005947:Glucose