MANOMETRIC RESPONSES OF HUMAN DUODENUM DURING INFUSION OF HCL, HYPEROSMOLAR SALINE, BILE AND OLEIC-ACID

Duodenal motor activity is incompletely understood. The purpose of thi s study was to define the contractile patterns of the duodenum that oc cur in response to are controlled injection of various solutions. In n ine healthy volunteers we placed a six channel perfused catheter, and recorded pressure activity in the antrum, pylorus and duodenum. Volume s 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 i nto the duodenum at 20 ml/min, starting 15 min after phase III migrato ry motor complex (MMC). A 20 mt bolus of each solution caused more act ivity (P < 0.05) than a 10 mL bolus, bur the motor pattern was similar . The control, 0.9% NaCl, produced occasional pressue waves, whereas b ile and sodium oleate induced more (P < 0.05) activity which consisted of low amplitude, isolated or clusters (2-4 cycle/min) of non-propaga ting 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 eith er at a single channel or at multiple channels, occurring simultaneous ly. The motility index was also greater (P < 0.05) than that induced b y other solutions. Additionally, within 2 min of infusion, a phase III MMC like pattern was observed in five of the nine subjects who receiv ed HCl and three of the nine who received 5% NaCl. A non-nutrient isoo smolar solution induced occasional motor activity HCl and hyperosmolar solutions induced mole frequent and large amplitude, segmental contra ctions whereas lipid and bile induced fewer and smaller amplitude cont ractions. The volume, the pH, the osmolar and the nutrient make up of the infusate may each influence the duodenal motor responses.