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Different types of contractions in rat colon and their modulation by oxidative stress

Different types of contractions in rat colon and their modulation by oxidative stress Abstract The aim of this study was to investigate the modulation of in vitro rat colonic circular muscle contractions by dextran sodium sulfate (DSS)-induced inflammation and in spontaneous inflammation in HLA-B27 rats. We also examined the potential role of hydrogen peroxide (H 2 O 2 ) in modulating excitation-contraction coupling. The muscle strips from the middle colon generated spontaneous phasic contractions and giant contractions (GCs), the proximal colon strips generated primarily phasic contractions, and the distal colon strips were mostly quiescent. The spontaneous phasic contractions and GCs were not affected by inflammation, but the response to ACh was suppressed in DSS-treated rats and in HLA-B27 rats. H 2 O 2 production was increased in the muscularis of the inflamed colon. Incubation of colonic muscle strips with H 2 O 2 suppressed the spontaneous phasic contractions and concentration and time dependently reduced the response to ACh; in the middle colon, it also increased the frequency of GCs. We conclude that H 2 O 2 mimics the suppression of the contractile response to ACh in inflammation. H 2 O 2 also selectively suppresses phasic contractions and increases the frequency of GCs, as found previously in inflamed dog and human colons. colonic inflammation dextran sodium sulfate giant contraction hydrogen peroxide giant migrating contractions Footnotes Address for reprint requests and other correspondence: S. K. Sarna, General Surgery, Medical College of Wisconsin–FWC, 9200 West Wisconsin Ave., Milwaukee, WI 53226 (E-mail: ssarna@mcw.edu ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Copyright © 2001 the American Physiological Society http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png AJP - Gastrointestinal and Liver Physiology The American Physiological Society

Different types of contractions in rat colon and their modulation by oxidative stress

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Publisher
The American Physiological Society
Copyright
Copyright © 2011 the American Physiological Society
ISSN
0193-1857
eISSN
1522-1547
Publisher site
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Abstract

Abstract The aim of this study was to investigate the modulation of in vitro rat colonic circular muscle contractions by dextran sodium sulfate (DSS)-induced inflammation and in spontaneous inflammation in HLA-B27 rats. We also examined the potential role of hydrogen peroxide (H 2 O 2 ) in modulating excitation-contraction coupling. The muscle strips from the middle colon generated spontaneous phasic contractions and giant contractions (GCs), the proximal colon strips generated primarily phasic contractions, and the distal colon strips were mostly quiescent. The spontaneous phasic contractions and GCs were not affected by inflammation, but the response to ACh was suppressed in DSS-treated rats and in HLA-B27 rats. H 2 O 2 production was increased in the muscularis of the inflamed colon. Incubation of colonic muscle strips with H 2 O 2 suppressed the spontaneous phasic contractions and concentration and time dependently reduced the response to ACh; in the middle colon, it also increased the frequency of GCs. We conclude that H 2 O 2 mimics the suppression of the contractile response to ACh in inflammation. H 2 O 2 also selectively suppresses phasic contractions and increases the frequency of GCs, as found previously in inflamed dog and human colons. colonic inflammation dextran sodium sulfate giant contraction hydrogen peroxide giant migrating contractions Footnotes Address for reprint requests and other correspondence: S. K. Sarna, General Surgery, Medical College of Wisconsin–FWC, 9200 West Wisconsin Ave., Milwaukee, WI 53226 (E-mail: ssarna@mcw.edu ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Copyright © 2001 the American Physiological Society

Journal

AJP - Gastrointestinal and Liver PhysiologyThe American Physiological Society

Published: Apr 1, 2001

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