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rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
1990-2-12
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pubmed:abstractText |
1. Inward unitary currents through inwardly rectifying K+ channels of myotubes derived from newborn rats or from a murine, clonal myoblast cell line were studied in the cell-attached configuration. Open-closed transitions of the channel were observed in the absence of blocking ions. 2. The single-channel conductance was 26.3 +/- 2.9 pS (mean + S.D., n = 14) with 150 mM-K+ pipette solution at room temperature (19-22 degrees C). The channel showed substates of conductance in addition to the main conductance state. A channel with a smaller conductance (8.9 +/- 2.6 pS, n = 4) was also but less frequently observed. 3. The probability of the channel being open is weakly voltage dependent: it decreased from 0.94 to 0.84 as the membrane was hyperpolarized from the resting potential (RP) + 20 mV to RP - 50 mV. 4. The lifetimes of the openings were distributed according to a single exponential. At least three exponentials were required to fit the frequency histogram of the lifetimes of all closed states. The mean open time showed a weak voltage dependence, while the mean closed times had little voltage dependence. 5. In the presence of external Na+, the open probability decreased from 0.89 to 0.43 and the mean open time decreased from 203 to 28 ms (40 mM-K+, 200 mM-Na+ pipette solution) when the patch membrane was hyperpolarized from RP - 40 mV to RP - 110 mV. The mean closed times were not different from those with 150 mM-K+, Na+-free pipette solution and showed little voltage dependence. 6. It is suggested that inactivation of the macroscopic inward currents during hyperpolarization results mainly from a voltage-dependent block by Na+ with relatively slow kinetics.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-1083489,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-13714851,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-13859478,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-14402240,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-16992124,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-2411932,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-2414434,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-2457698,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-2600845,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-3873536,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-4547276,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-4679725,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-512954,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-568176,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6111797,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6131450,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6270629,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6272286,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6273573,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6296368,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6323703,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6323704,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-6325785,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2607427-7381423
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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 |
414
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
111-24
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:2607427-Animals,
pubmed-meshheading:2607427-Cells, Cultured,
pubmed-meshheading:2607427-Electrophysiology,
pubmed-meshheading:2607427-Homeostasis,
pubmed-meshheading:2607427-Ions,
pubmed-meshheading:2607427-Mathematics,
pubmed-meshheading:2607427-Mice,
pubmed-meshheading:2607427-Muscles,
pubmed-meshheading:2607427-Potassium Channels,
pubmed-meshheading:2607427-Rats,
pubmed-meshheading:2607427-Sodium
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pubmed:year |
1989
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pubmed:articleTitle |
Single inwardly rectifying potassium channels in cultured muscle cells from rat and mouse.
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pubmed:affiliation |
Department of Physiology, University of Leicester.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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