Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1977-6-30
pubmed:abstractText
At 15 degrees C, direct stimulation of frog single muscle fibers at a frequency of 20 Hz produced a tetanic tension that remained constant for 20 s and then declined. The decline was reversed during 1-s interruptions of the stimulus train in the first 50 s of stimulation, but not with longer stimulation. Posttetanic potentiation (PTP), characterized by prolonged twitch relaxation and contraction times and elevation of twitch height, remained for 10-40 min after a 10-s tetanus and for at least 90 min after a 50- to 150-s tetanus. Posttetanic fatigue appeared only after at least 50s of tetanic stimulation. Fatigue was manifested invariably by a reduction in the height of a 200-ms tetanic contraction and usually by a reduction in twitch height after PTP. Fatigued fibers recovered normal contractile responses in 40-160 min. Hypertonic solutions, which blocked contraction in response to tetanic stimulation, prevented posttetanic fatigue but not PTP. The observations suggest that fatigue is caused by a failure in excitation-contraction coupling, probably in relation to consumption of metabolic substrates. Even 10-s tetani which do not produce fatigue can affect muscle contractile function for up to 40 min.
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
232
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C185-90
pubmed:dateRevised
2009-10-27
pubmed:meshHeading
pubmed:year
1977
pubmed:articleTitle
Fatigue and posttetanic potentiation in single muscle fibers of the frog.
pubmed:publicationType
Journal Article, In Vitro