voltage-gated K+ A channel (K+ channel IA , ISA, IA, A type K+ channel)
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Function
- rapidly inactivating A current.
- control of maintained repetitive firing.
- neuronal somatodendritic subthreshold A-type K+ current
- component of ensemble of voltage-gated ionic currents that determine somatodendritic signal integration
- operates in subthreshold range of membrane potentials
- relatively fast inactivation & recovery from inactivation
- allegedly participates in long-term potentiation
- contributes majority of K+ current in dendrites of hippocampal CA1 pyramidal cells[3]
Channel characteristics:
- conductance: 6 +/- 0.6 pS
- inactivated with time constant of 23 +/1 2 ms at +54 mV
Structure
- consists of 4 voltage-gated K+ channel subfamily A (alpha) subunits
Expression
- found on CA1 pyramidal cells.
Pathology
- Abeta interferes with currents of K+ A channels, leading to increased dendritic Ca+2 influx, synaptic dysfunction & neurodegeneration[2] (putative)
More general terms
References
- ↑ Lotan I, Dascal N, Naor Z, Boton R. Modulation of vertebrate brain Na+ and K+ channels by subtypes of protein kinase C. FEBS Lett. 1990 Jul 2;267(1):25-8. PMID: https://www.ncbi.nlm.nih.gov/pubmed/1694792
- ↑ 2.0 2.1 Chen C beta-Amyloid increased dendritic Ca+2 influx by inhibiting the A-type K+ current in hippocampal CA1 neurons. Biochem Biophys Res Commun 2005, 338:1913 PMID: https://www.ncbi.nlm.nih.gov/pubmed/16289381
- ↑ 3.0 3.1 Chen X and Johnston D Properties of single voltgage-dependent K+ channels in dendrites of CA1 pyramidal neurones of rat hippocampus. J Physiol 2004, 559:187 PMID: https://www.ncbi.nlm.nih.gov/pubmed/15218076
- ↑ Storm Nature 336 379 1988
- ↑ Jerng HH, Pfaffinger PJ, Covarrubias M. Molecular physiology and modulation of somatodendritic A-type potassium channels. Mol Cell Neurosci. 2004 Dec;27(4):343-69 PMID: https://www.ncbi.nlm.nih.gov/pubmed/15555915