|
rdf:type |
|
|
lifeskim:mentions |
|
|
pubmed:issue |
2
|
|
pubmed:dateCreated |
1997-1-9
|
|
pubmed:abstractText |
We studied monovalent permeability of Ca2+ release-activated Ca2+ channels (ICRAC) in Jurkat T lymphocytes following depletion of calcium stores. When external free Ca2+ ([Ca2+]o) was reduced to micromolar levels in the absence of Mg2+, the inward current transiently decreased and then increased approximately sixfold, accompanied by visibly enhanced current noise. The monovalent currents showed a characteristically slow deactivation (tau = 3.8 and 21.6 s). The extent of Na+ current deactivation correlated with the instantaneous Ca2+ current upon readdition of [Ca2+]o. No conductance increase was seen when [Ca2+]o was reduced before activation of ICRAC. With Na+ outside and Cs+ inside, the current rectified inwardly without apparent reversal below 40 mV. The sequence of conductance determined from the inward current at -80 mV was Na+ > Li+ = K+ > Rb+ >> Cs+. Unitary inward conductance of the Na+ current was 2.6 pS, estimated from the ratios delta sigma2/delta Imean at different voltages. External Ca2+ blocked the Na+ current reversibly with an IC50 value of 4 microM. Na+ currents were also blocked by 3 mM Mg2+ or 10 microM La3+. We conclude that ICRAC channels become permeable to monovalent cations at low levels of external divalent ions. In contrast to voltage-activated Ca2+ channels, the monovalent conductance is highly selective for Na+ over Cs+. Na+ currents through ICRAC channels provide a means to study channel characteristics in an amplified current model.
|
|
pubmed:grant |
|
|
pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-1309940,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-2413461,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-2428919,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-2519622,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-2580082,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-3137323,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-6090645,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-6328315,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7491254,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7540169,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7576655,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7612237,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7639685,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7644512,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7760017,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7776241,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7918985,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-7943286,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8146203,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8184490,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8189045,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8229840,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8355806,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8382682,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8392195,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8395025,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8407897,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8740373,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8842217-8786341
|
|
pubmed:language |
eng
|
|
pubmed:journal |
|
|
pubmed:citationSubset |
IM
|
|
pubmed:chemical |
|
|
pubmed:status |
MEDLINE
|
|
pubmed:month |
Aug
|
|
pubmed:issn |
0006-3495
|
|
pubmed:author |
|
|
pubmed:issnType |
Print
|
|
pubmed:volume |
71
|
|
pubmed:owner |
NLM
|
|
pubmed:authorsComplete |
Y
|
|
pubmed:pagination |
787-94
|
|
pubmed:dateRevised |
2009-11-18
|
|
pubmed:meshHeading |
pubmed-meshheading:8842217-Anions,
pubmed-meshheading:8842217-Calcium,
pubmed-meshheading:8842217-Calcium Channels,
pubmed-meshheading:8842217-Cations, Monovalent,
pubmed-meshheading:8842217-Cell Membrane Permeability,
pubmed-meshheading:8842217-Electric Conductivity,
pubmed-meshheading:8842217-Humans,
pubmed-meshheading:8842217-Jurkat Cells,
pubmed-meshheading:8842217-Kinetics,
pubmed-meshheading:8842217-Membrane Potentials,
pubmed-meshheading:8842217-Sodium
|
|
pubmed:year |
1996
|
|
pubmed:articleTitle |
Conductance and permeation of monovalent cations through depletion-activated Ca2+ channels (ICRAC) in Jurkat T cells.
|
|
pubmed:affiliation |
Department of Physiology and Biophysics, University of California at Irvine 92717, USA.
|
|
pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
|
