Examining enteric nervous system function in rat and mouse: an interspecies comparison of colonic motility

Abstract

Gastrointestinal motility is crucial to gut health and has been associated with different disorders such as inflammatory bowel diseases and post-operative ileus. Despite rat and mouse being the two animal models most widely used in gastrointestinal research, minimal studies in rats have investigated gastrointestinal motility. Therefore, our study provides a comparison of colonic motility in the mouse and rat to clarify species differences and assess the relative effectiveness of each animal model for colonic motility research. To our knowledge, this is the first study to use ex vivo video imaging techniques to assess rat colonic motility. We identified differences in the histology of the proximal colon such that the rat had larger villus height-to-width and villus height-to-crypt depth ratios compared with mouse. Since gut motility is tightly regulated by the enteric nervous system (ENS), we investigated how colonic contractile activity within each species responds to modulation of the ENS inhibitory neuronal network. Here we used Nω‐nitro‐l‐arginine (NOLA), an inhibitor of nitric oxide synthase (NOS) to assess proximal colon responses to the stimulatory effect of blocking the major inhibitory neurotransmitter, nitric oxide (NO). In rats, the frequency of proximal colonic contractions increased in the presence of NOLA (versus control levels) to a greater extent than in mice. This is despite a similar number of NOS-expressing neurons in the myenteric plexus across species. Given this increase in colonic contraction frequency, the rat represents another relevant animal model for investigating how gastrointestinal motility is regulated by the inhibitory neuronal network of the ENS.

Prebiotics counteract the morphological and functional changes secondary to chronic cisplatin exposition in the proximal colon of mice

“…10,12,35 The significant reduction of stool production found in the Cspl group at the end of the treatment agrees with the finding recorded in the functional study. The motility pattern of the colon exhibits very complex features and a variety of patterns have been described differing in relation to animal species 36,37 and colonic segments. 38,39 Presently, the strips of proximal colon exhibit a spontaneous contractile activity consisting of rhythmic changes in isometric tension.…”

Spinal cord injury-induced neurogenic bowel: A role for host-microbiome interactions in bowel pain and dysfunction

“…Moreover, both CGRP isoforms induce synthesis and release of nitric oxide (NO), a primary signaling molecule for the inhibitory ENS ( Toth et al, 2009 ) providing a molecular mechanism by which CGRP could inhibit peristalsis, in line with the clinical presentation of NB and the present preclinical data. Further, NMDA receptors have been shown to be involved in visceral nociception and hypersensitivity ( Yip et al, 2022 ), vagal afferent hyperexcitability ( McRoberts et al, 2001 ), and are associated with functional abdominal pain/irritable bowel syndrome ( Vance et al, 2015 ). NMDA receptor expression and activity can be altered by CGRP signaling through RAMP1 ( Iyengar et al, 2017 ).…”

The Effects of Short- and Long-Term Ingestion of Plastic Toxin Bisphenol A on Gastrointestinal Transit Time in Rats

“…The NO is a potent smooth muscle relaxant and relaxes all the smooth muscles in the body [ 6 , 16 - 17 ]. There is ample evidence to suggest the involvement of nitric oxide in regulating intestinal contractility [ 6 , 18 - 19 ]. A recent study claimed that BPA caused a significant inhibition of duodenal movement by involving NO [ 6 ].…”