Evaluation of gastrointestinal motility in awake rats: a learning exercise for undergraduate biomedical students

Abstract

Current medical curricula devote scarce time for practical activities on digestive physiology, despite frequent misconceptions about dyspepsia and dysmotility phenomena. Thus, we designed a hands-on activity followed by a small-group discussion on gut motility. Male awake rats were randomly submitted to insulin, control, or hypertonic protocols. Insulin and control rats were gavage fed with 5% glucose solution, whereas hypertonic-fed rats were gavage fed with 50% glucose solution. Insulin treatment was performed 30 min before a meal. All meals (1.5 ml) contained an equal mass of phenol red dye. After 10, 15, or 20 min of meal gavage, rats were euthanized. Each subset consisted of six to eight rats. Dye recovery in the stomach and proximal, middle, and distal small intestine was measured by spectrophotometry, a safe and reliable method that can be performed by minimally trained students. In a separate group of rats, we used the same protocols except that the test meal contained (99m)Tc as a marker. Compared with control, the hypertonic meal delayed gastric emptying and gastrointestinal transit, whereas insulinic hypoglycemia accelerated them. The session helped engage our undergraduate students in observing and analyzing gut motor behavior. In conclusion, the fractional dye retention test can be used as a teaching tool to strengthen the understanding of basic physiopathological features of gastrointestinal motility.

Effect of Flavonoid Rich Root Extract Of Glycyrrhizaglabra on Gastric Emptying and Gastrointestinal Transit in Albino Wistar Rats

“…The model has been used to measure gastric emptying and gastrointestinal transit for both synthetic as well as herbal products [10][11][12][13][14][15]. Hence, the current study employed phenol red meal model to investigate the possible prokinetic effects of GutGard.…”

Aortocaval fistula delays gastric emptying of liquid test meal in awake rats

“…A dye dilution technique, previously adapted by us (34), was used to evaluate the GE of a liquid (1.5 ml) test meal (0.5 mg/ml of phenol red in 5% glucose solution). After 10, 20, or 30 min of the meal gavage, the rats, respectively named 10, 20, and 30-min postprandial subgroups, were euthanized by an intravenous thiopental overdose.…”

Atrial stretch increases the gastric tonus of anesthetized rats

“…Rats individually housed in Bollman's cages were kept fasting for 24 h with free access to an oral hydration solution composed of 75 mM Na + , 65 mM Cl − , 20 mM K + , 75 mEq glucose, and 10 mM citrate. This procedure assures normal levels of glycemia and hydration during the fasting interval necessary to clear the rat stomach from its residues (Souza et al 2009). …”