Manometric responses of human duodenum during infusion of HCl, hyperosmolar saline, bile and oleic acid

Abstract

Duodenal motor activity is incompletely understood. The purpose of this study was to define the contractile patterns of the duodenum that occur in response to rate controlled injection of various solutions. In nine healthy volunteers we placed a six channel perfused catheter, and recorded pressure activity in the antrum, pylorus and duodenum. Volumes of 10 and 20 mL of 0.9% NaCl, 100 mM HCl (pH 1), 5% NaCl (1711 mOsm/kg), human bile and iso-osmolar sodium oleate were randomly injected into the duodenum at 20 ml/min, starting 15 min after phase III migratory motor complex (MMC). A 20 mL bolus of each solution caused more activity (P < 0.05) than a 10 mL bolus, but the motor pattern was similar. The control, 0.9% NaCl, produced occasional pressure waves, whereas bile and sodium oleate induced more (P < 0.05) activity which consisted of low amplitude, isolated or clusters (2-4 cycle/min) of non-propagating pressure waves that occurred at random sites. In three subjects, oleate produced isolated pyloric phasic contractions. In contrast, HCl and 5% NaCl induced high amplitude pressure waves that were seen either at a single channel or at multiple channels, occurring simultaneously. The motility index was also greater (P < 0.05) than that induced by other solutions. Additionally, within 2 min of infusion, a phase III MMC like pattern was observed in five of the nine subjects who received HCl and three of the nine who received 5% NaCl. A non-nutrient iso-osmolar solution induced occasional motor activity. HCl and hyperosmolar solutions induced more frequent and large amplitude, segmental contractions whereas lipid and bile induced fewer and smaller amplitude contractions. The volume, the pH, the osmolar and the nutrient make up of the infusate may each influence the duodenal motor responses.

Effects of Intraduodenal Bile on Interdigestive Gastrointestinal and Gallbladder Motility in Healthy Subjects

“…Although the amount of bile or placebo infused is exceeded by the total amount of fluid through the perfusion system, no disturbing effects of this perfusion technique are expected, as the fluid is rapidly absorbed by the gut. The absence of effect on the MMC in our study is in agreement with previous studies in humans using intraduodenal infusion of native bile or pancreatico-biliary juice or bile acids [16, 32]. Moreover, release of motilin by bile infusion per se [16, 17]was not observed in our study, as the increased plasma motilin level probably reflected a normal physiological increase with the MMC.…”

“…Second, the presence of an absolute refractory period [31]was accounted for by infusing bile at a standardised moment in the MMC cycle. Third, we accounted for an equal pH, volume and osmolarity [32]of the infusates. Although the amount of bile or placebo infused is exceeded by the total amount of fluid through the perfusion system, no disturbing effects of this perfusion technique are expected, as the fluid is rapidly absorbed by the gut.…”

Patterns of Small Intestinal Motor Activity During Intraluminal Infusion of Elementary Diets in Dogs

“…Attempts to characterize this motor activity during the fed period have yielded contradictory results [3][4][5][6][7] that may be related to the species studied, composition of test meals, route of administration, and caloric load.…”

Nonnutritive sweetener consumption in humans: effects on appetite and food intake and their putative mechanisms

“…Beverages of higher energy density empty from the stomach more slowly (102, 107), independent of osmotic effects (108, 109). Similarly, the gastric emptying rate is reduced with higher osmotic challenges (110–112) independently of energy content (113). Activation of both gastric stretch and intestinal nutrient signals results in synergistic effects on satiety (101, 114).…”