title: Ca2+ responses in enteric glia are mediated by connexin-43 hemichannels and modulate colonic transit in mice.
abstract: OBJECTIVE
  In the enteric nervous system, neurotransmitters initiate changes in calcium (Ca(2+) responses) in glia, but it is not clear how this process affects intestinal function. We investigated whether Ca(2+)-mediated responses in enteric glia are required to maintain gastrointestinal function.
  
  
  METHODS
  We used in situ Ca(2+) imaging to monitor glial Ca(2+) responses, which were manipulated with pharmacologic agents or via glia-specific disruption of the gene encoding connexin-43 (Cx43) (hGFAP::CreER(T2+/-)/Cx43(f/f) mice). Gastrointestinal function was assessed based on pellet output, total gut transit, colonic bead expulsion, and muscle tension recordings. Proteins were localized and quantified by immunohistochemistry, immunoblot, and reverse transcription polymerase chain reaction analyses.
  
  
  RESULTS
  Ca(2+) responses in enteric glia of mice were mediated by Cx43 hemichannels. Cx43 immunoreactivity was confined to enteric glia within the myenteric plexus of the mouse colon; the Cx43 inhibitors carbenoxolone and 43Gap26 inhibited the ability of enteric glia to propagate Ca(2+) responses. In vivo attenuation of Ca(2+) responses in the enteric glial network slowed gut transit overall and delayed colonic transit--these changes are also observed during normal aging. Altered motility with increasing age was associated with reduced glial Ca(2+)-mediated responses and changes in glial expression of Cx43 messenger RNA and protein.
  
  
  CONCLUSIONS
  Ca(2+)-mediated responses in enteric glia regulate gastrointestinal function in mice. Altered intercellular signaling between enteric glia and neurons might contribute to motility disorders.
authors.affiliation: Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA.
authors.forename: Jonathon
authors.initials: J
authors.lastname: McClain
authors.affiliation: Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Grubišić
authors.affiliation: Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824.
authors.forename: David
authors.initials: D
authors.lastname: Fried
authors.affiliation: Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA.|Department of Pediatrics Division of Pediatric Gastroenterology Hepatology And Nutrition at Nemours Chlidren's Hospital. Orlando, FL 32827, USA.
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Gomez-Suarez
authors.affiliation: Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA.
authors.forename: Gina M
authors.initials: GM
authors.lastname: Leinninger
authors.affiliation: Département de microbiologie-infectiologie et d'immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.|Centre de recherche du CHU de Québec, Québec, QC, G1V 4G2 Canada.
authors.forename: Jean
authors.initials: J
authors.lastname: Sévigny
authors.affiliation: Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, USA.|Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Parpura
authors.affiliation: Neuroscience Program and Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824 USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Gulbransen
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D015220:Calcium Channels / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D003106:Colon / Q000502:physiology*; D018031:Connexin 43 / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D017615:Enteric Nervous System / Q000502:physiology*; D005260:Female; D005772:Gastrointestinal Transit / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009457:Neuroglia / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D015220:Calcium Channels; D018031:Connexin 43; C543076:GJA1 protein, mouse
keywords: ADP; ATP; Aging; CBX; Ca(2+); Cx43; EG; ENS; ER(T2); GFAP; Intestinal Nervous System; Mouse Model; Purines; adenosine diphosphate; adenosine triphosphate; calcium; carbenoxolone; connexin-43; enteric glia; enteric nervous system; glial fibrillary acidic protein; i-cKO; inducible and conditional knockout; mRNA; messenger RNA; moa; months of age; mutated estrogen receptor