Comparison of Two Orogastric Feeding Markers for Measuring Gastrointestinal Motor Functions in Rats

Abstract

Rat gastrointestinal (GI) transit parameters measured with charcoal and radiochromium were compared. Animals were fed with a calorie-free liquid test meal which contained 10% charcoal and radiochromium (0.5 µCi ml^–1) via a transiently placed orogastric catheter. The rats were sacrificed at 1, 5, 15, 30, 60 and 120 min, respectively, since feeding. Various motor parameters were measured. Charcoal transit ratio, gastric emptying and geometric center were time dependent. Charcoal transit ratio occasionally showed a positive correlation with gastric emptying in the very late experimental periods. Concerning the correlation of charcoal transit ratio and geometric center, negative and positive correlations were seen in the very early and late periods, respectively. We conclude that the rat charcoal transit ratio has limited value to replace the GI transit parameters determined by feeding radiochromium.

Gastrointestinal transit times in mice and humans measured with 27Al and 19F nuclear magnetic resonance

“…The animals received a standard laboratory mice chow and drinking water ad libitum. Prior to the first MR examination, each mouse was given a gavage of 0.3 ml of the 19 F/ 27 Al contrast agent prepared as described above. Immediately after the gavage the animal was placed in prone position in a narrow tube, which was inserted into the 19 F/ 27 Al resonator used for the MR examinations.…”

“…Specific tagging of capsules with conventional contrast agents based on the alteration of the magnetic susceptibility has not mitigated this problem (9). Conversely, 19 F-MRI of fluorinated agents has been shown to provide excellent selective contrast in images of the murine GI tract (10,11). Due to the lack of endogenous fluorine-containing metabolites in soft tissues, the 19 F-MR signal can be assigned exclusively to the fluorinated contrast agent present inside the GI tract.…”

“…Conversely, 19 F-MRI of fluorinated agents has been shown to provide excellent selective contrast in images of the murine GI tract (10,11). Due to the lack of endogenous fluorine-containing metabolites in soft tissues, the 19 F-MR signal can be assigned exclusively to the fluorinated contrast agent present inside the GI tract. The intensity of the 19 F-MR signal is therefore a measure of the amount of contrast agent present in the GI tract.…”

“…Due to the lack of endogenous fluorine-containing metabolites in soft tissues, the 19 F-MR signal can be assigned exclusively to the fluorinated contrast agent present inside the GI tract. The intensity of the 19 F-MR signal is therefore a measure of the amount of contrast agent present in the GI tract. By monitoring the intensity variations of the 19 F signal, the flow of the contrast agent out of the GI tract can be followed noninvasively.…”

“…The intensity of the 19 F-MR signal is therefore a measure of the amount of contrast agent present in the GI tract. By monitoring the intensity variations of the 19 F signal, the flow of the contrast agent out of the GI tract can be followed noninvasively.…”