Source:http://linkedlifedata.com/resource/pubmed/id/15245486
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
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| pubmed:dateCreated |
2004-7-12
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| pubmed:abstractText |
The neuronal voltage-gated sodium channels play a vital role in the action potential waveform shaping and propagation. Here, we report the effects of prolonged depolarization (1-160 s) on the detailed kinetics of activation, fast inactivation and recovery from slow inactivation in the rNa(v)1.2a voltage-gated sodium channel alpha-subunit expressed in Chinese hamster ovary (CHO) cells. Wavelet analysis revealed that the duration and amplitude of a prolonged sustained depolarization altered all the steady state and kinetic parameters of the channel in a pseudo-oscillatory fashion with time-variable period and amplitude, often superimposed on a linear trend. The half steady state activation potential showed a reversible depolarizing shift of 5-10 mV with duration of prolonged depolarization, while half steady state inactivation potential showed a hyperpolarizing shift of 43-55 mV. The time periods for most of the parameters relating to activation and fast and slow inactivation, lie close to 28-30 s, suggesting coupling of these kinetic processes through an oscillatory mechanism. Co-expression of the beta1-subunit affected the time periods of oscillation (close to 22 s for alpha + beta1) in steady state activation parameters. Application of a pulse protocol that mimicked paroxysmal depolarizing shift (PDS), a kind of depolarization seen in epileptic discharges, instead of a sustained depolarization, also caused oscillatory behaviour in the rNav1.2a alpha-subunit. This inherent pseudo-oscillatory mechanism may regulate excitability of the neurons, account for the epileptic discharges and subthreshold membrane potential oscillation and offer a molecular memory mechanism intrinsic to the neurons, independent of synaptic plasticity.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Green Fluorescent Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Luminescent Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium Channel Blockers,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium Channels,
http://linkedlifedata.com/resource/pubmed/chemical/Tetrodotoxin
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| pubmed:status |
MEDLINE
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| pubmed:month |
Jul
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| pubmed:issn |
0953-816X
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:volume |
20
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
127-43
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| pubmed:dateRevised |
2006-11-15
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| pubmed:meshHeading |
pubmed-meshheading:15245486-Analysis of Variance,
pubmed-meshheading:15245486-Animals,
pubmed-meshheading:15245486-CHO Cells,
pubmed-meshheading:15245486-Cricetinae,
pubmed-meshheading:15245486-Cricetulus,
pubmed-meshheading:15245486-Electric Stimulation,
pubmed-meshheading:15245486-Green Fluorescent Proteins,
pubmed-meshheading:15245486-Ion Channel Gating,
pubmed-meshheading:15245486-Kinetics,
pubmed-meshheading:15245486-Luminescent Proteins,
pubmed-meshheading:15245486-Membrane Potentials,
pubmed-meshheading:15245486-Models, Neurological,
pubmed-meshheading:15245486-Neural Inhibition,
pubmed-meshheading:15245486-Patch-Clamp Techniques,
pubmed-meshheading:15245486-Sodium Channel Blockers,
pubmed-meshheading:15245486-Sodium Channels,
pubmed-meshheading:15245486-Tetrodotoxin,
pubmed-meshheading:15245486-Time Factors,
pubmed-meshheading:15245486-Transfection
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| pubmed:year |
2004
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| pubmed:articleTitle |
Induction of pseudo-periodic oscillation in voltage-gated sodium channel properties is dependent on the duration of prolonged depolarization.
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| pubmed:affiliation |
Molecular Biophysics Unit, Indian Institute of Science, Bangalore-560012, India.
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| pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, Non-U.S. Gov't
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