Referenced in: none

Automatically associated channels: Kv1.4 , Kv3.1 , Kv4.1 , Kv4.2 , Kv4.3

Title: Kv4.2 mRNA abundance and A-type K(+) current amplitude are linearly related in basal ganglia and basal forebrain neurons.

Authors: T Tkatch, G Baranauskas, D J Surmeier

Journal, date & volume: J. Neurosci., 2000 Jan 15 , 20, 579-88

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/10632587

Abstract
A-type K(+) currents are key determinants of repetitive activity and synaptic integration. Although several gene families have been shown to code for A-type channel subunits, recent studies have suggested that Kv4 family channels are the principal contributors to A-type channels in the somatodendritic membrane of mammalian brain neurons. If this hypothesis is correct, there should be a strong correlation between Kv4 family mRNA and A-type channel protein or aggregate channel currents. To test this hypothesis, quantitative single-cell reverse transcription-PCR analysis of Kv4 family mRNA was combined with voltage-clamp analysis of A-type K(+) currents in acutely isolated neurons. These studies revealed that Kv4.2 mRNA abundance was linearly related to A-type K(+) current amplitude in neostriatal medium spiny neurons and cholinergic interneurons, in globus pallidus neurons, and in basal forebrain cholinergic neurons. In contrast, there was not a significant correlation between estimates of Kv4.1 or Kv4.3 mRNA abundance and A-type K(+) current amplitudes. These results argue that Kv4.2 subunits are major constituents of somatodendritic A-type K(+) channels in these four types of neuron. In spite of this common structural feature, there were significant differences in the voltage dependence and kinetics of A-type currents in the cell types studied, suggesting that other determinants may create important functional differences between A-type K(+) currents.