K+ A Channel

From Anvita Health Wiki

Contents 1 Function 2 Structure 3 Expression 4 Pathology 5 More General Terms 6 References

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

• voltage-gated K+ channel

References

1. 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: [1]
2. 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: [2]
3. 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: [3]
4. Storm Nature 336 379 1988
5. 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: [4]

voltage-gated K+ A channel (K+ channel IA , ISA, IA, A type K+ channel)