Duodenogastric reflux of intestinal infusions in rats is volume dependent

Experiments employing infusions of nutrients into the gastrointestinal tract commonly deliver large volumes of solutions without evaluating the possibility that reflux of the infusate to more orad sites may occur. To assess this possibility for one conventional paradigm, rats with gastric fistulas and intestinal catheters were infused intraduodenally (4.0 to 5.0 cm distal to pylorus) in association with a meal. Infusions of 0.0 ml to 15.0 ml of 3% glucose and a dye marker or 0.9% saline containing a dye marker were delivered at 1 ml/min, and stomach contents were assayed for the infusates. All three probes were detected in stomach contents. The glucose marker proved the most sensitive of the three and indicated that duodenogastric reflux occurred in a dose-dependent manner with infusions > 2.5 ml.