Measurements of duodenal wall motility, mucosal fluid transport and alkaline secretion. Description and evaluation of a methodological approach in the anaesthetized cat.

This paper describes and evaluates a method for simultaneous recordings of duodenal motility and mucosal secretions in chloralose-anaesthetized cats. Biliary and pancreatic secretions were diverted by separate cannulation of each duct. A 2 cm segment of the proximal duodenum was isolated between two luminally situated balloons (the proximal balloon being positioned immediately distal to the pylorus). Each balloon was connected to a barostatic device maintaining a constant pressure within the balloon independent of the degree of contraction. Motor activity in the duodenal wall was recorded as changes in balloon volume. The duodenal segment was perfused at a constant rate with isotonic saline containing [14C]PEG 4000 as a non-absorbable marker. The recovered perfusate was sampled in 5 min fractions and analysed with regard to alkalinity (back titration) and concentration of marker (liquid scintillation). Net alkalinization and net fluid transport was calculated with conventional equations. The sensitivity of the analytical procedures was tested bench-side. The technique was evaluated in vivo during basal conditions and during acid exposure of the mucosa. Exposing the duodenal segment to 30 mM HCl induced a marked change in the duodenal functional state with the occurrence of a polarized duodenal motility pattern, net fluid secretion and an increased alkaline secretion.