Identification of medium/high-threshold extrinsic mechanosensitive afferent nerves to the gastrointestinal tract

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dc.contributor.authorSong, X.
dc.contributor.authorNan Chen, B.
dc.contributor.authorZagorodnyuk, V.
dc.contributor.authorLynn, P.
dc.contributor.authorBlackshaw, L.
dc.contributor.authorGrundy, D.
dc.contributor.authorBrunsden, A.
dc.contributor.authorCosta, M.
dc.contributor.authorBrookes, S.
dc.date.issued2009
dc.description.abstractBACKGROUND & AIMS: Large distentions reliably evoke sensation from the noninflamed, nonischemic bowel, but the specialized afferent axonal structures responsible have not been morphologically identified. We investigated whether their transduction sites are located on major blood vessels close to and within the gut wall. METHODS: In vitro extracellular recordings were made from mesenteric nerve trunks in guinea pig ileum, combined with rapid axonal dye filling and immunohistochemical analysis of nerve trunks. RESULTS: Recordings revealed sensory fibers with focal mechanosensitive sites in the mesenteries that could be activated by von Frey hairs and by stretch. Dye filling revealed varicose branching sensory axons on mesenteric blood vessels but no other anatomically specialized structures in mesenteric membranes or the serosa. Large-amplitude stretch and von Frey hairs also activated sensory endings within the gut wall itself but only if the submucosa was present; mechanotransduction sites in the serosa or outer muscle layers were sparse. Mechanosensitive sites in submucosa were exclusively associated with submucosal blood vessels. Submucosal endings had significantly higher thresholds to stretch than specialized low-threshold mechanoreceptors characterized previously in the rectum (P<.05) and were therefore classified as medium/high-threshold mechanoreceptors. Capsaicin (0.3–1 _mol/L) activated most mechanosensitive mesenteric (68%) and submucosal (85%) afferent endings. Similar intramural mechanosensitive afferent endings on blood vessels also exist in the colon and bladder. CONCLUSIONS: Varicose branching axons of sensory neurons on intramural blood vessels, previously shown to mediate sensory vasodilation, are transduction sites for medium/ high-threshold, stretch-sensitive mechanoreceptors, encoding large distentions in hollow viscera.
dc.description.statementofresponsibilityXingyun Song, Bao Nan Chen, Vladimir P. Zagorodnyuk, Penny A. Lynn, L. Ashley Blackshaw, David Grundy, Alan M. Brunsden, Marcello Costa and Simon J.H. Brookes
dc.identifier.citationGastroenterology, 2009; 137(1):274-284
dc.identifier.doi10.1053/j.gastro.2009.02.061
dc.identifier.issn0016-5085
dc.identifier.issn1528-0012
dc.identifier.orcidBlackshaw, L. [0000-0003-1565-0850]
dc.identifier.urihttp://hdl.handle.net/2440/58069
dc.language.isoen
dc.publisherW B Saunders Co
dc.rights© 2009 by the AGA Institute
dc.source.urihttps://doi.org/10.1053/j.gastro.2009.02.061
dc.subjectColon
dc.subjectIleum
dc.subjectMesenteric Arteries
dc.subjectMesenteric Veins
dc.subjectNeurons, Afferent
dc.subjectEnteric Nervous System
dc.subjectMechanoreceptors
dc.subjectAnimals
dc.subjectGuinea Pigs
dc.subjectCapsaicin
dc.subjectSensory Thresholds
dc.subjectMechanotransduction, Cellular
dc.subjectEvoked Potentials
dc.subjectStress, Mechanical
dc.subjectTime Factors
dc.subjectUrinary Bladder
dc.titleIdentification of medium/high-threshold extrinsic mechanosensitive afferent nerves to the gastrointestinal tract
dc.typeJournal article
pubs.publication-statusPublished

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