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What are the roles of the many different types of potassium channel expressed in cerebellar granule cells?

Mathie, Alistair, Clarke, Catherine E., Ranatunga, Kishani M., Veale, Emma L. (2003) What are the roles of the many different types of potassium channel expressed in cerebellar granule cells? Cerebellum, 2 (1). pp. 11-25. (doi:10.1080/14734220310015593) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:5686)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided.
Official URL:
https://doi.org/10.1080/14734220310015593

Abstract

Potassium (K) channels have a key role in the regulation of neuronal excitability. Over a hundred different subunits encoding distinct K channel subtypes have been identified so far. A major challenge is to relate these many different channel subunits to the functional K currents observed in native neurons. In this review, we have concentrated on cerebellar granule neurons (CGNs). We have considered each of the three principal super families of K channels in turn, namely, the six transmembrane domain, voltage-gated super family, the two transmembrane domain, inward-rectifier super family and the four transmembrane domain, leak channel super family. For each super family, we have identified the subunits that are expressed in CGNs and related the properties of these expressed channel subunits to the functional currents seen in electrophysiological recordings from these neurons. In some cases, there are strong molecular candidates for proteins underlying observed currents. In other cases the correlation is less clear. We show that at least 26 potassium channel alpha subunits are moderately or strongly expressed in CGNs. Nevertheless, a good empirical model of CGN function has been obtained with just six distinct K conductances. The transient KA current in CGNs, seems due to expression of Kv4.2 channels or Kv4.2/4.3 heteromers, while the KCa current is due to expression of large-conductance slo channels. The G-protein activated KIR current is probably due to heteromeric expression of KIR3.1 and KIR3.2. Perhaps KIR2.2 subunits underlie the KIR current when it is constitutively active. The leak conductance can be attributed to TASK-1 and or TASK-3 channels. With less certainty, the IK-slow current may be due to expression of one or more members of the KCNQ or EAG family. Lastly, the delayed-rectifier Kv current has as many as six different potential contributors from the extensive Kv family of alpha subunits. Since many of these subunits are highly regulated by neurotransmitters, physiological regulators and, often, auxiliary subunits, the resulting electrical properties of CGNs may be highly dynamic and subject to constant fine-tuning.

Item Type: Article
DOI/Identification number: 10.1080/14734220310015593
Subjects: Q Science > QP Physiology (Living systems)
Divisions: Divisions > Division of Natural Sciences > Medway School of Pharmacy
Depositing User: Alistair Mathie
Date Deposited: 14 Mar 2009 06:38 UTC
Last Modified: 09 Mar 2023 11:29 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/5686 (The current URI for this page, for reference purposes)

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