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rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
1996-10-1
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pubmed:abstractText |
1. The Na(+)-K+ pump current (Ip) was studied in sino-atrial (SA) node cells of rabbits using the whole-cell patch-clamp technique. 2. With 50 mM Na+ in the pipette solution ([Na+]pip), changing the external K+ concentration (-K+-o) from 0 to 5.4 mM caused the holding current to shift in an outward direction and reach a new steady state. The current-voltage relationships obtained by subtraction of current traces recorded at 0 mM Ko+ from those recorded at 5.4 mM Ko+ revealed time-independent and voltage-dependent characteristics. The external K(+)-induced current was completely blocked by external application of 10 microM ouabain, indicating the existence of Ip in SA node cells of rabbit heart. 3. Ip increased as [K+]o increased. With 30 mM Na+pip, Ip at 0 mV was activated by [K+]o with non-linear least-squares fit parameters for the Hill equation of K0.5 of 1.4 mM and a Hill coefficient (nH) of 1.2 (n = 7). 4. The cation dependence of the K+ site of the Na(+)-K+ pump was examined using various monovalent cations. The sequence was K+ > or = Rb+ > Cs+ > > > Li+. 5. Ip at 0 mV also increased as [Na+]pip was increased from 10 to 150 mM at 5.4 mM Ko+, with a K0.5 value of 14 mM and a nH of 1.3 (n = 54). 6. Ip at 0 mV was reduced by lowering the temperature from 37 to 25 degrees C with 30 mM Na+pip and 5.4 mM Ko+. The temperature coefficient (Q10) for Ip was 2.1 (n = 27). 7. With 10 mM Na+pip and 5.4 mM Ko+, the half-activation voltage of Ip was -52 +/- 16 mV and the current at this voltage was 22.5 +/- 3.5 pA (n = 10), indicating that Ip contributes significantly to the background outward current during the normal pacemaker potential of SA node cells.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-1172612,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-1194884,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-1317444,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-13889686,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-14210262,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-1665855,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2299332,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2299333,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2410650,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2430183,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2454287,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2457676,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2581143,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2607333,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2607334,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-2726436,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-3288092,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-4473142,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-512947,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-6024446,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-6087268,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-6095174,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-6270629,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-6292328,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-7177773,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-7312557,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-7431245,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-8304428,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8745278-8380502
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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 |
Jan
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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:day |
1
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pubmed:volume |
490 ( Pt 1)
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
51-62
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
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pubmed:year |
1996
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pubmed:articleTitle |
Sodium--potassium pump current in rabbit sino-atrial node cells.
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pubmed:affiliation |
Heart Institute of Japan, Tokyo Women's Medical College, Shinjuku-ku.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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