Three-dimensional imaging of the stomach: role of pylorus in the emptying of liquids.

Using the dynamic spatial reconstructor and manometry, we measured gastric emptying, pyloric size, and antral contractile activity in three anesthetized dogs in the prone position. Our objective is to evaluate the effect of intestinal perfusion of equicaloric, neutral, and isosmolar nutrients (Maltose 32.5 mg/ml, casein hydrolysate 32.5 mg/ml, and oleic acid 15.5 mg/ml) at a constant rate of 10 ml/min in the proximal jejunum on the dynamics of the antropyloric region. Isotonic saline perfusion was used as a control solution. Test meal in the stomach was 600 ml of isotonic Gastrograffin. Antral phasic pressure activity was recorded using an antroduodenal six-channel (ports 5 mm apart) perfused probe (2 mm OD). Gastric emptying in response to intestinal perfusion of fat was significantly slower (P less than 0.02) in comparison to other nutrients or isotonic saline. There was no significant difference in the maximum or minimum pyloric diameter in response to the four intestinal perfusates. However, the pylorus was closed for a significantly longer duration (P less than 0.05) during the perfusion of fat in the upper intestine. Antral contractions were related to pyloric opening in an "antral contraction followed by pyloric opening" sequence. This study suggests that the presence of fat in the upper intestine delays gastric emptying and that this effect is regulated in part by increased resistance to flow offered by the pylorus.