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rdf:type |
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lifeskim:mentions |
umls-concept:C0007961,
umls-concept:C0026649,
umls-concept:C0028066,
umls-concept:C0034493,
umls-concept:C0039629,
umls-concept:C0242692,
umls-concept:C0449432,
umls-concept:C1179435,
umls-concept:C1280500,
umls-concept:C1524073,
umls-concept:C1546426,
umls-concept:C1548280,
umls-concept:C1548799,
umls-concept:C1705248,
umls-concept:C1706211
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pubmed:dateCreated |
1987-2-19
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pubmed:abstractText |
The effects of tetracaine and nifedipine on asymmetric charge movement in rabbit muscle fibres were examined to investigate whether mammalian charge movement could be subdivided into several components. Tetracaine (0.05-0.2 mM) stopped contraction in every sternomastoid fibre examined (n = 9) and reduced the asymmetric charge (moved by depolarizing steps to 0 mV) by 15% (S.E. of mean 3%). Tetracaine had little effect on the charge moved at potentials more negative than the threshold potential (established in the absence of the drug). Application of the Ca2+ channel blocker nifedipine (2 or 10 microM), reduced the mean maximum asymmetric charge to 50% (+/- 4) of the control value in twenty-three sternomastoid fibres and to 32% (+/- 5) in four soleus fibres. Increasing the concentration of nifedipine to 120 microM had little further effect. The charge moved at potentials more negative than -60 mV was unaffected by nifedipine. A similar result was found with 30 microM-D600 (two fibres). 10 microM-nifedipine completely blocked Ca2+ currents (external [Ca2+] = 8 mM), but 0.15 microM-nifedipine only had a small effect on either the Ca2+ current or charge movement in the four fibres examined. Contractions could no longer be elicited in eleven of eighteen fibres within 6 min of the application of 2 or 10 microM-nifedipine. However, in the remaining seven fibres contractions could be elicited with unchanged thresholds over 30 min, even in the presence of 50 microM-nifedipine. Nifedipine did not noticeably effect q gamma. It is suggested that nifedipine might prevent contraction only when, for other reasons, the normal release of Ca2+ from the sarcoplasmic reticulum has been disrupted and contraction is dependent on the inflow of external Ca2+. The amount of asymmetric charge moved by depolarizing steps was about 50% greater with a holding potential of -110 mV than with one of -90 mV. This 'extra' charge was not suppressed by nifedipine.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-1082506,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-1082507,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-1082509,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-1082510,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-1083424,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-1087641,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-1265479,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-16068161,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-2409971,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-2580976,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-2581141,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-3795082,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-3981474,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-4540479,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-458722,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-480239,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-5639790,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6090646,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6262506,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6267261,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6304026,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6315856,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6315862,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6332900,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6600842,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6603512,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6604805,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6609364,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6620180,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6975814,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6975815,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6978399,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-6980275,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3795083-859639
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Jul
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pubmed:issn |
0022-3751
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
376
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
85-100
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:3795083-Action Potentials,
pubmed-meshheading:3795083-Animals,
pubmed-meshheading:3795083-Calcium,
pubmed-meshheading:3795083-Membrane Potentials,
pubmed-meshheading:3795083-Muscle Contraction,
pubmed-meshheading:3795083-Muscles,
pubmed-meshheading:3795083-Nifedipine,
pubmed-meshheading:3795083-Rabbits,
pubmed-meshheading:3795083-Sensory Thresholds,
pubmed-meshheading:3795083-Tetracaine,
pubmed-meshheading:3795083-Time Factors
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pubmed:year |
1986
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pubmed:articleTitle |
Components of charge movement in rabbit skeletal muscle: the effect of tetracaine and nifedipine.
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pubmed:publicationType |
Journal Article,
In Vitro
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