Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1988-5-13
pubmed:abstractText
1. The effects of variations in pH between 7.00 and 6.20 on Ca2+ -activated tension development and maximum velocity of shortening (Vmax) were examined in skinned single skeletal fibres from rat slow-twitch soleus and fast-twitch superficial (s.v.l.) and deep (d.v.l.) regions of the vastus lateralis muscle. 2. At pH 6.50, Vmax was depressed to a similar degree in each of the soleus, d.v.l., and s.v.l. fibres. Lowering pH to 6.20 resulted in a further decline in Vmax in all fibres; however, differences between the slow fibres, identified by SDS-polyacrylamide gel electrophoresis, and fast fibres were apparent, with soleus retaining a significantly greater proportion of its control Vmax (0.83 +/- 0.03 in soleus vs. 0.69 +/- 0.03 in s.v.l.; mean +/- S.E.M.). 3. Maximum force production decreased significantly as pH was reduced. Peak force at pH 6.50, relative to that at pH 7.00, was significantly greater in soleus (0.80 +/- 0.01) than in the s.v.l. (0.75 +/- 0.01) fibres. At pH 6.20 these differences between slow and fast fibres were still greater, in that soleus fibres generated significantly greater relative forces (0.73 +/- 0.01) than did d.v.l. (0.67 +/- 0.02) or s.v.l. (0.63 +/- 0.02) fibres. 4. As pH was lowered the tension-pCa relationship shifted to the right (i.e. to higher [Ca2+]), indicating a reduction in the Ca2+ sensitivity of tension development. The [Ca2+] necessary to achieve half-maximal tension in both the slow- and fast-twitch fibres increased approximately 5-fold when pH was lowered from 7.00 to 6.20. Furthermore, in the case of the soleus, the Ca2+ threshold for tension development was 45 times greater at pH 6.20 than at pH 7.00, while in the fast-twitch fibres, this increase was 4-fold. 5. Increased [H+] differentially affected the steepness of the tension-pCa relationship between slow and fast fibres. As pH was lowered, the steepness of the lower portion of the tension-pCa curve increased in the soleus and decreased in d.v.l. and s.v.l., suggesting that apparent positive co-operativity of tension development had increased in soleus and decreased in d.v.l. and s.v.l. fibres. 6. These results (1) demonstrate an increased resistance to H+ ion-mediated contractile dysfunction in slow- compared to fast-twitch single fibres, and (2) support the hypothesis that muscular fatigue resulting from short-term, intense muscular contraction may in part be related to elevated H+ ion concentration.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-20501, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-25957, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-26054, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-2940217, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-2994867, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-30066, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-308189, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-314510, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-314975, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-3597214, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-36597, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-3700385, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-3723106, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-3795099, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-39630, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-4019463, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-4056736, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-4227924, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-4243638, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-4256989, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-4261616, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-4333578, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-4348494, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-5010039, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-5013602, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-533865, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6085331, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6142051, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6189421, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6215428, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6403557, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6643469, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6807974, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6882858, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6974015, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6974740, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6980967, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-6981684, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-7053577, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-7143257, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-7264969, http://linkedlifedata.com/resource/pubmed/commentcorrection/3446809-7358047
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-3751
pubmed:author
pubmed:issnType
Print
pubmed:volume
393
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
727-42
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Greater hydrogen ion-induced depression of tension and velocity in skinned single fibres of rat fast than slow muscles.
pubmed:affiliation
Department of Physiology, School of Medicine, University of Wisconsin, Madison 53706.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.