Exp Neurobiol.  2017 Aug;26(4):179-185. 10.5607/en.2017.26.4.179.

Spike Frequency Adaptation in Neurons of the Central Nervous System

• Ha GE
• Cheong E

• KMID: 2389004
• DOI: http://doi.org/10.5607/en.2017.26.4.179

Abstract

Neuronal firing patterns and frequencies determine the nature of encoded information of the neurons. Here we discuss the molecular identity and cellular mechanisms of spike-frequency adaptation in central nervous system (CNS) neurons. Calcium-activated potassium (K(Ca)) channels such as BK(Ca) and SK(Ca) channels have long been known to be important mediators of spike adaptation via generation of a large afterhyperpolarization when neurons are hyper-activated. However, it has been shown that a strong hyperpolarization via these KCa channels would cease action potential generation rather than reducing the frequency of spike generation. In some types of neurons, the strong hyperpolarization is followed by oscillatory activity in these neurons. Recently, spike-frequency adaptation in thalamocortical (TC) and CA1 hippocampal neurons is shown to be mediated by the Ca²âº-activated Cl- channel (CACC), anoctamin-2 (ANO2). Knockdown of ANO2 in these neurons results in significantly reduced spike-frequency adaptation accompanied by increased number of spikes without shifting the firing mode, which suggests that ANO2 mediates a genuine form of spike adaptation, finely tuning the frequency of spikes in these neurons. Based on the finding of a broad expression of this new class of CACC in the brain, it can be proposed that the ANO2-mediated spike-frequency adaptation may be a general mechanism to control information transmission in the CNS neurons.

Keyword

spike-frequency adaptation; anoctamin-2; calcium-activated chloride channel; calcium-activated potassium channel; afterhyperpolarization; thalamocortical neuron

MeSH Terms

Action Potentials
Brain
Central Nervous System*
Fires
Neurons*
Potassium
Potassium Channels, Calcium-Activated
Potassium
Potassium Channels, Calcium-Activated