|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Institute of Infection, Immunity and Inflammation, University of Calgary, Calgary, Canada; Dept. of Cell Biology, Physiology and Immunology, Universitat Autonoma de Barcelona, Bercelona, Spain; Department of Human Biology, Technische Universitat Munchen, Munich, Germany; Mucosal Inflammation Research Group, University of Calgary, Calgary, Canada
* To whom correspondence should be addressed. E-mail: ksharkey{at}ucalgary.ca.
The role of enteric glia in gastrointestinal physiology remains largely unexplored. We examined the actions of the gliotoxin fluorocitrate (FC) on intestinal motility, secretion and inflammation, after assessing its efficacy and specificity in vitro. FC (100 µM) caused a significant decrease in the phosphorylation of the glucose analogue, 2-NBDG, in enteric glial cultures and a reduction in glial uptake of the fluorescent dipeptide Ala-Lys-AMCA in both the ileum and the colon. Dipeptide uptake by resident murine macrophages or guinea pig myenteric neurons was unaffected by FC. Incubation of isolated guinea pig ileal segments with FC caused a specific and significant increase in glial expression of the phosphorylated form of the extracellular signal-regulated kinase 1/2. Disruption of enteric glial function with FC in mice reduced small intestinal motility in vitro, including a significant decrease in basal tone and the amplitude of contractility in response to electrical field stimulation. Mice treated with 10 or 20 µmoles/kg of FC twice daily for 7 days demonstrated a concentration-dependent decrease in small intestinal transit. In contrast, no changes in colonic transit or ion transport in vitro were observed. There were no changes in glial or neuronal morphology, any signs of inflammation in the FC treated mice, or any change in the number of myenteric nitric oxide synthase-expressing neurons. We conclude that FC treatment causes enteric glial dysfunction, without causing intestinal inflammation. Our data suggest that enteric glia are involved in the modulation of enteric neural circuits underlying the regulation of intestinal motility.
This article has been cited by other articles:
![]() |
M. Duncan, A. Mouihate, K. Mackie, C. M. Keenan, N. E. Buckley, J. S. Davison, K. D. Patel, Q. J. Pittman, and K. A. Sharkey Cannabinoid CB2 receptors in the enteric nervous system modulate gastrointestinal contractility in lipopolysaccharide-treated rats Am J Physiol Gastrointest Liver Physiol, July 1, 2008; 295(1): G78 - G87. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |