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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:dateCreated |
1984-8-15
|
| pubmed:abstractText |
Single channels activated by (+)-tubocurarine (curare) were recorded from rat myotubes using the patch-clamp technique. The agonist-like action of curare does not result from a contaminant molecule, as the same effects were observed with curare purified by high-performance liquid chromatography. A curare-activated channel can adopt two levels of conductance: full (F) or partial (P). The F state has a slope conductance of 40 pS (identical to that of the acetylcholine (ACh)-activated channel) and the P state has a conductance of 13 pS. At low concentrations of agonist (ACh or curare), the distribution of channel open times is biphasic. The briefer channels may result from the binding of a single agonist molecule whereas the longer-lived channels probably occur following the binding of two agonist molecules. The mean open time of the F state decreases with increasing curare concentration. It is shown that band-width limitations are likely to account for only a very small part of this observed reduction. In contrast, the mean open time of the P state is independent of the concentration of curare. A simple interpretation is that the F state is susceptible to channel blockade by curare, whereas the P state is not. The P state preceded the F state almost as often as it followed the F state; it can also be observed separately from the F state. The fraction of events including a P state increases from about 4% in the presence of 1 microM-curare to 30% at 100 microM-curare. This fraction is also increased by hyperpolarization. When the curare concentration is increased, the F-state frequency first increases and then decreases at higher concentration. This frequency is also decreased by hyperpolarization. The decrease in F-state frequency is probably related to channel blockade by curare; it cannot be wholly accounted for by problems associated with limited time resolution. A synthetic analogue of curare, (+)- tubocurine dimethiodide presents an agonist activity similar to that of curare but with a faster closing rate for both F and P states. The various actions of curare are summarized in two possible models where the P state is interpreted as either a partially open channel or a channel which is partially blocked.
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| pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-14407080,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-301253,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-307251,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-315462,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-33387,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-400609,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-42780,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-4717155,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-490329,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6188060,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6253616,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6253617,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6270629,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6273528,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6273742,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6273743,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6288894,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6308151,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-671288,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-6978400,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-714165,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-7146904,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-723945,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6330348-934285
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Apr
|
| pubmed:issn |
0022-3751
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
349
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
353-74
|
| pubmed:dateRevised |
2009-11-18
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| pubmed:meshHeading |
pubmed-meshheading:6330348-Acetylcholine,
pubmed-meshheading:6330348-Animals,
pubmed-meshheading:6330348-Curare,
pubmed-meshheading:6330348-Electric Conductivity,
pubmed-meshheading:6330348-Ion Channels,
pubmed-meshheading:6330348-Membrane Potentials,
pubmed-meshheading:6330348-Models, Biological,
pubmed-meshheading:6330348-Muscles,
pubmed-meshheading:6330348-Probability,
pubmed-meshheading:6330348-Rats,
pubmed-meshheading:6330348-Tubocurarine
|
| pubmed:year |
1984
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| pubmed:articleTitle |
A patch-clamp study of the partial agonist actions of tubocurarine on rat myotubes.
|
| pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, Non-U.S. Gov't
|