Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/61090
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Type: Journal article
Title: The first intestinal motility patterns in fetal mice are not mediated by neurons or interstitial cells of Cajal
Author: Roberts, R.
Ellis, M.
Gwynne, R.
Bergner, A.
Lewis, M.
Spencer, E.
Bornstein, J.
Young, H.
Citation: Journal of Physiology-London, 2010; 588(7):1153-1169
Publisher: Blackwell Publishing Ltd
Issue Date: 2010
ISSN: 0022-3751
1469-7793
Statement of
Responsibility: 
Rachael R. Roberts, Melina Ellis, Rachel M. Gwynne, Annette J. Bergner, Martin D. Lewis, Elizabeth A. Beckett, Joel C. Bornstein and Heather M. Young
Abstract: In mature animals, neurons and interstitial cells of Cajal (ICC) are essential for organized intestinal motility. We investigated motility patterns, and the roles of neurons and myenteric ICC (ICC-MP), in the duodenum and colon of developing mice in vitro. Spatiotemporal mapping revealed regular contractions that propagated in both directions from embryonic day (E)13.5 in the duodenum and E14.5 in the colon. The propagating contractions, which we termed ripples, were unaffected by tetrodotoxin and were present in the intestine of embryonic Ret null mutant mice, which lack enteric neurons. Neurally mediated motility patterns were first observed in the duodenum at E18.5. To examine the possible role of ICC-MP, three approaches were used. First, intracellular recordings from the circular muscle of the duodenum did not detect slow wave activity at E16.5, but regular slow waves were observed in some preparations of E18.5 duodenum. Second, spatiotemporal mapping revealed ripples in the duodenum of E13.5 and E16.5 W/Wv embryos, which lack KIT+ ICC-MP and slow waves. Third, KIT-immunoreactive cells with the morphology of ICC-MP were first observed at E18.5. Hence, ripples do not appear to be mediated by ICC-MP and must be myogenic. Ripples in the duodenum and colon were abolished by cobalt chloride (1 mm). The L-type Ca2+ channel antagonist nicardipine (2.5 μm) abolished ripples in the duodenum and reduced their frequency and size in the colon. Our findings demonstrate that prominent propagating contractions (ripples) are present in the duodenum and colon of fetal mice. Ripples are not mediated by neurons or ICC-MP, but entry of extracellular Ca2+ through L-type Ca2+ channels is essential. Thus, during development of the intestine, the first motor patterns to develop are myogenic.
Keywords: Colon; Duodenum; Neurons; Myenteric Plexus; Fetus; Animals; Mice; Mice, Mutant Strains; Cobalt; Nicardipine; Tetrodotoxin; Calcium Channels, L-Type; Gastrointestinal Motility; Muscle Contraction; Female; Male; Proto-Oncogene Proteins c-kit; Interstitial Cells of Cajal
Rights: © 2010 The Authors. Journal compilation © 2010 The Physiological Society
RMID: 0020096019
DOI: 10.1113/jphysiol.2009.185421
Grant ID: http://purl.org/au-research/grants/nhmrc/454351
http://purl.org/au-research/grants/nhmrc/565319
Appears in Collections:Molecular and Biomedical Science publications

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