Pyloric motor function during emptying of a liquid meal from the stomach in the conscious pig.

Abstract

SUMMARY1. In six conscious pigs antral, pyloric and duodenal pressures were recorded with a 5-5 cm sleeve sensor and multiple perfused side holes. The manometric assembly was positioned by dual point transmucosal potential difference measurement. Gastric emptying was measured by drainage of the proximal duodenum through a Thomas cannula. Pressures were correlated with emptying of ingested radiolabelled 5 % dextrose. Alteration of emptying was produced by infusion into the more distal duodenum of nutrient and non-nutrient solutions of differing osmolalities.2. Motor activity of the pylorus and antrum was stimulated by ingestion and modulated by intraduodenal infusion. Duodenal infusion of normal saline was associated with antro-pyloric pressure waves and rapid emptying of the ingested liquid. Duodenal infusion of dextrose, fatty acid, amino acids and hyperosmolar saline was associated with stimulation of isolated pyloric pressure waves, suppression of antral pressure waves and slowing of gastric emptying.3. The dose-response relationship of these effects was investigated using varying rates of intraduodenal dextrose infusions. The emptying rate of the ingested liquid was inversely related to the rates of delivery of dextrose to the duodenum, directly related to the rate of antro-pyloric pressure waves and inversely related to the rate of isolated pyloric pressure waves.4. Clearly defined episodes of pulsatile flow produced slightly more than half of the total emptying that occurred. This pulsatile flow was intimately associated in time with antro-pyloric pressure waves. Sequences of isolated pyloric pressure waves were associated with near cessation of emptying. When there were periods of absent pyloric antral pressure waves, flow rates intermediate between the rapid emptying of pulsatile flow during antro-pyloric pressure waves and the near cessation of flow during isolated pyloric pressure waves occurred.5. The findings suggest a major role for the pylorus in the control of emptying of liquids from the stomach, both as a component of an antro-pyloric peristaltic pump and as a resistor to transpyloric flow during nutrient and hyperosmolar stimulation of duodenal receptors.

The Pharmacological Effect of Omeprazole on Water Gastric Emptying: A Study Based on an Impedance Measure

“…Our study showing similar lag times confirms the notion of unchanged proximal stomach motility after omeprazole premedication [24]. In addition to the proximal stomach providing a pressure gradient to help liquid GE, the antrum and pylorus are indeed essential in liquid GE, since the fluid is delivered in the pulsatile flow according to the antropyloroduodenal coordination [35][36][37]. Based on observations of omeprazole-elicited antral contraction plus acid removal followed by dull duodenal brake and inhibited duodenal/pyloric tone, enhanced water GE may be expected, since powerful antral motility and low resistance already exists, in its delivered route.…”

Influence of jejunal nutrients on transpyloric flow and pyloric resistance in pigs

“…The length of the nutrient exposed jejunal segment was about equal to 2/lOth of the total small intestine length; a value within the range of those explored by others (Lin et al, 1989). Furthermore, the inhibition of phasic antral motility and the exclusive presence of isolated pyloric pressure events observed after the infusion of nutrients were identical to those already described in humans, dogs and pigs (Heddle et al, 1988a, b;Treacy et al, 1990 (Miller et al, 1981 (Miller et al, 1981 (Heddle et al, 1988a, b), acidification of the duodenum (Allescher et al, 1989) and duodenal cold stress (Fone et al, 1990). In our study, their uneffectiveness in reducing gastric emptying might be related to the presence of the fundic barostat that maintained the fundic pressure, thus avoiding the possible fundic distension generated by the inhibition of gastric emptying (Fone et al, 1990;Edelbroek et al, 1993).…”

“…Furthermore, the stomach is capable of considerable compensation before the overall rate of gastric emptying is compromized (Malbert and Mathis, 1994). Since nutrients infused at the jejunal level decrease fundic tone (Azpiroz and Malagelada, 1985a) (Treacy et al, 1990) and it enabled a steady pyloric resistance for prolonged periods (Malbert and Mathis, 1994;Malbert et al, 1995 (Dent, 1976). The 3.5 mm diameter manometric probe was inserted into the antrum through a small incision in the ventral corpus and positioned so that one side hole was located in the terminal antrum -2 cm from the orad end of the sleeve and one within the pyloric canal at 2 cm from the orad end of the sleeve.…”

Inhibitory effects and mechanisms of intestinal electrical stimulation on gastric tone, antral contractions, pyloric tone, and gastric emptying in dogs

“…The critical factors that control gastric emptying are gastric tone, antral peristalsis, pyloric resistance, and duodenal feedback control. Dysfunction of any of these factors results in impairment of gastric emptying (13,19,22,24,25,27,36,38,45,47,48). Effective peristaltic antral contractions play a major role in solid gastric emptying (13,27).…”