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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1982-2-12
pubmed:abstractText
Portal hypertension was induced in rats by partial ligation of the hepatic branches of the portal vein. After 5 days the transluminal pressure of the portal vein was measured, and the vessel was fixed in situ for electron-microscopy, or dissected out and mounted in an apparatus recording force and shortening. Portal veins from sham-operated animals were used as controls. Portal venous pressure had increased about twofold after the partial ligation and the cross-sectional area of the longitudinal muscle layer about twofold. Number of muscle cells per mm2 cross-sectional area decreased to half of the control value, whereas extracellular space in the muscle layer and the dry weight of the preparations were unaltered. Number of cells was unchanged suggesting that no hyperplasia had occurred. Length-passive force relations were shifted towards higher force values in the hypertrophic vessels, whereas passive stress-strain characteristics were similar. The structures that carry passive tension have thus increased in proportion to the vessel as a whole. Length-active tension curves obtained by stimulation with AC current or high K+ solutions indicated that the hypertrophic vessels could not, in relation to optimal length for active force, shorten to the same extent as control vessels. Maximum active tension per vessel was unaltered whereas force per unit muscle area and force per cell had decreased. As the preparations were supramaximally stimulated and had optimal extracellular Ca2+ concentrations we suggest that the amount of functional contractile proteins has not increased in proportion to the increase in size of the muscle cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0001-6772
pubmed:author
pubmed:issnType
Print
pubmed:volume
112
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
463-71
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1981
pubmed:articleTitle
Structural and mechanical alterations in hypertrophic venous smooth muscle.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't