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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5 Pt 1
pubmed:dateCreated
1992-6-25
pubmed:abstractText
Previous studies showed that colonic smooth muscle develops less contractile force to neurohumoral stimulation when associated with mucosal inflammation. This study evaluated 1) the Ca2+ dependence for colonic smooth muscle contraction, 2) the maximum velocity of muscle shortening (Vmax), and 3) changes in 20-kDa myosin light-chain (MLC) phosphorylation in distal circular colonic muscle from healthy rabbits and from rabbits with experimental colitis, induced by Formalin and immune complexes. The isometric tension of unskinned muscle stimulated with bethanechol or KCl was less (P less than 0.05) in animals with colitis compared with the control group. In saponin-skinned muscle, the amplitude of the maximal tension at [Ca2+] of 3 x 10(-7) M was decreased (P less than 0.05) in colitis animals (4.3 +/- 0.9 x 10(4) N/m2, n = 7) compared with healthy animals (10.5 +/- 2.4 x 10(4) N/m2, n = 6). However, the ED50 for Ca2+ stimulation was similar (P greater than 0.05) in both groups. When MLC was thiophosphorylated with ATP gamma S, the tension development was decreased in colitis (2.1 +/- 0.3 x 10(4) N/m2, n = 5; P less than 0.01) compared with normals (5.0 +/- 1.4 x 10(4) N/m2, n = 5). In healthy animals, phosphorylation of 20-kDa MLC increased rapidly to 51.2 +/- 3.1% within 15 s after stimulation and subsequently declined to 19.0 +/- 2.1% at 5 min. Vmax was maximal (0.14 Lo/s) 13 s after stimulation and declined before maximal active isometric stress. In colitis animals, the 20-kDa MLC phosphorylation (P less than 0.05) and the Vmax (P less than 0.01) were decreased.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
262
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
G921-6
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
An abnormal rate of actin myosin cross-bridge cycling in colonic smooth muscle associated with experimental colitis.
pubmed:affiliation
Harbor-University of California, Los Angeles, Medical Center, Torrance 90502.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.