Effect of posture on gastric emptying of nonnutrient liquids and antropyloroduodenal motility

The effects of posture on gastric emptying, intragastric distribution, and antropyloroduodenal motility after ingestion of a nonnutrient liquid have been evaluated. In seven healthy volunteers antropyloroduodenal pressures were measured for 30 min after ingestion of 150 ml of normal saline in two different positions: sitting and left lateral. Saline drinks were radiolabeled and ingested both before and after intravenous atropine (4 micrograms/kg). Rates of emptying from both the total (P 6 cm) antropyloric pressure waves (P < 0.05) and isolated pyloric pressure waves (P < 0.05) in the sitting position. Intravenous atropine slowed emptying in both positions (P < 0.05) and in the sitting position decreased (P < 0.05) the number of antropyloric pressure waves. After atropine, gastric emptying was also faster in the sitting compared with the decubitus position (P < 0.05), although there was no difference in antropyloric or isolated pyloric pressure waves between the two postures. We conclude that the effects of gravity on gastric emptying of nonnutrient liquids are likely to reflect changes in both antropyloric motility and intragastric distribution.Anvari, Mehran, Michael Horowitz, Robert Fraser, Anne Maddox, Jennifer Myers, John Dent, and Glyn G. Jamieson

Effects of glyceryl trinitrate on the pyloric motor response to intraduodenal triglyceride infusion in humans

The retardation of gastric emptying induced by infusion of triglyceride into the small intestine is associated with suppression of antral pressure waves and stimulation of basal pyloric tone in combination with phasic pressure waves localized to the pylorus. The role of nitric oxide (NO) mechanisms in the control of pyloric motility was evaluated in 12 healthy male subjects (21–43 years), using the NO donor glyceryl trinitrate (GTN). Antropyloric pressures were measured with a manometric assembly incorporating nine sideholes, spanning the antrum and proximal duodenum, and a pyloric sleeve sensor. On separate days, an intraduodenal triglyceride infusion (10% intralipid at l mL min-1) was started during antral phase I activity and continued for 60 min. On one of the days GTN (600 μg) was given sublingually 20 min after start of the triglyceride infusion. The tonic pyloric motor response to triglyceride [5.6 (SEM 0.8.) vs. 2.7 (1.3) mmHg, P <0.001] and both the number [3.2 (0.2) vs. 2.2 (0.2) min-1, P <0.05] and amplitude [40 (4) vs. 27 (5) mmHg, P <0.05] of phasic isolated pyloric pressure waves were reduced by GTN. These observations suggest that NO mechanisms are involved in the regulation of pyloric motor activity in humans.Sun, W. M.; Doran, S.; Lingenfelser, Th.; Hebbard, G. S.; Morley, J. E.; Dent, J.; Horowitz, M