X‐ray analysis of gastrointestinal motility in conscious mice. Effects of morphine and comparison with rats

Abstract

Background Non‐invasive methods to study gastrointestinal (GI) motility are of high interest, particularly in chronic studies. Amongst these, radiographic techniques after contrast intragastric administration may offer many advantages. In previous studies, we have successfully and reproducibly applied these techniques together with a semiquantitative analysis method to characterize the effect of different drugs, acutely or repeatedly administered in rat models, but we have never before used these techniques in mice. These are very convenient in basic research. Our aim was to determine if our method is also valid in mice. Additionally, we determined the effect of morphine on GI motor function in both species. Methods Animals received an intraperitoneal administration of morphine (at 10 and 5 mg/kg for rats and mice, respectively). Twenty min later, barium contrast (at 2 g/mL) was gavaged (2.5 and 0.4 mL for rats and mice respectively) and serial X‐rays were obtained 0–8 h after contrast. X‐rays were analyzed as previously described, using a semiquantitative score to build motility curves for each GI region. Key Results Motility was much faster in mice than in rats for all GI regions. Morphine at the doses used significantly depressed motility in both species to a similar extent if the whole gut or the upper GI regions (stomach, small intestine) were considered, although its effect seemed to be more intense in the lower GI regions (caecum, colorectum) in rats than in mice. Conclusions & Inferences We have validated our X‐rays method for its use in mice.

Gastrointestinal dysfunction and enteric neurotoxicity following treatment with anticancer chemotherapeutic agent 5‐fluorouracil

“…Speed of gastrointestinal transit was calculated as time in minutes taken to reach each region of the gastrointestinal tract (stomach, small intestines, cecum, and large intestines). Organ emptying was calculated as the time taken for complete barium emptying from specific gastrointestinal regions (stomach, small intestines) …”

“…Organ emptying was calculated as the time taken for complete barium emptying from specific gastrointestinal regions (stomach, small intestines). [19][20][21]…”

Radiographic dose‐dependency study of loperamide effects on gastrointestinal motor function in the rat. Temporal relationship with nausea‐like behavior

“…The effects of Lop 1 and Lop 10 on gastrointestinal motility were comparable to those of the cannabinoid agonist AM841 at 0.1 and 0.5 mg kg −1 , respectively, where only AM841 at 0.5 mg kg −1 was able to induce significant antinociception, hypothermia, and catalepsy . At 10 mg kg −1 , morphine effects on gastrointestinal motility were not as intense as those of loperamide at the same dose . Interestingly, as for morphine and cannabinoids, the intestine was clearly more sensitive to loperamide than the stomach.…”

“…32 At 10 mg kg −1 , morphine effects on gastrointestinal motility were not as intense as those of loperamide at the same dose. 64 Interestingly, as for morphine 64 and cannabinoids, 29,30,32 the intestine was clearly more sensitive to loperamide than the stomach.…”

Irinotecan-Induced Gastrointestinal Dysfunction Is Associated with Enteric Neuropathy, but Increased Numbers of Cholinergic Myenteric Neurons

“…Speed of gastrointestinal transit was calculated as time in min taken to reach each region of the gastrointestinal tract (stomach, small intestines, caecum, and colon). Organ emptying was calculated as the time taken for complete barium emptying from specific gastrointestinal regions (stomach, small intestines) (Cabezos et al, 2008, 2010; Girón et al, 2015). …”