| Differential roles of stretch-sensitive pelvic nerve afferents innervating mouse distal colon and rectum. | |
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MedLine Citation:
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PMID: 20075141 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Information about colorectal distension (i.e., colorectal dilation by increased intraluminal pressure) is primarily encoded by stretch-sensitive colorectal afferents in the pelvic nerve (PN). Despite anatomic differences between rectum and distal colon, little is known about the functional roles of colonic vs. rectal afferents in the PN pathway or the quantitative nature of mechanosensory encoding. We utilized an in vitro mouse colorectum-PN preparation to investigate pressure-encoding characteristics of colorectal afferents. The colorectum with PN attached was dissected, opened longitudinally, and pinned flat in a Sylgard-lined chamber. Action potentials of afferent fibers evoked by circumferential stretch (servo-controlled force actuator) were recorded from the PN. Stretch-sensitive fibers were categorized into the following four groups: colonic muscular, colonic muscular/mucosal, rectal muscular, and rectal muscular/mucosal. Seventy-nine stretch-sensitive PN afferents evenly distributed into the above four groups were studied. Rectal muscular afferents had significantly greater stretch-responses than the other three groups. Virtually all rectal afferents (98%) had low thresholds for response and encoded stimulus intensity into the noxious range without obvious saturation. Most colonic afferents (72%) also had low thresholds (<14 mmHg), but a significant proportion (28%) had high thresholds (>18 mmHg) for response. These high-threshold colonic afferents were sensitized to stretch by inflammatory soup; response threshold was significantly reduced (from 23 to 12 mmHg), and response magnitude significantly increased. These results suggest that the encoding of mechanosensory information differs between colonic and rectal stretch-sensitive PN afferents. Rectal afferents have a wide response range to stretch, whereas high-threshold colonic afferents likely contribute to visceral nociception. |
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Authors:
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Bin Feng; Pablo R Brumovsky; Gerald F Gebhart |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2010-01-14 |
Journal Detail:
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Title: American journal of physiology. Gastrointestinal and liver physiology Volume: 298 ISSN: 1522-1547 ISO Abbreviation: Am. J. Physiol. Gastrointest. Liver Physiol. Publication Date: 2010 Mar |
Date Detail:
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Created Date: 2010-02-17 Completed Date: 2010-03-15 Revised Date: 2011-07-25 |
Medline Journal Info:
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Nlm Unique ID: 100901227 Medline TA: Am J Physiol Gastrointest Liver Physiol Country: United States |
Other Details:
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Languages: eng Pagination: G402-9 Citation Subset: IM |
Affiliation:
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Center for Pain Research, Department of Anesthesiology, University of Pittsburgh, Pennsylvania 15213, USA. fengb@upmc.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Action Potentials
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physiology Animals Colon / anatomy & histology, innervation*, physiology* Intestinal Mucosa / anatomy & histology, innervation, physiology Male Mechanoreceptors / physiology* Mice Mice, Inbred C57BL Muscle, Smooth / anatomy & histology, innervation, physiology Neural Conduction / physiology Neuronal Plasticity / physiology Neurons, Afferent / physiology Pelvis / innervation* Physical Stimulation Rectum / anatomy & histology, innervation*, physiology* Sensory Thresholds / physiology |
| Grant Support | |
ID/Acronym/Agency:
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NS 19912/NS/NINDS NIH HHS |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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