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Cortical HCN channels: function, trafficking and plasticity
Author(s) -
Shah Mala M.
Publication year - 2014
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2013.270058
Subject(s) - neuroscience , neurotransmission , hyperpolarization (physics) , hcn channel , chemistry , ion channel , synaptic potential , membrane potential , biophysics , neuron , synaptic plasticity , pyramidal cell , potassium channel , microbiology and biotechnology , biology , biochemistry , receptor , hippocampus , stereochemistry , nuclear magnetic resonance spectroscopy
The hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels belong to the superfamily of voltage‐gated potassium ion channels. They are, however, activated by hyperpolarizing potentials and are permeable to cations. Four HCN subunits have been cloned, of which HCN1 and HCN2 subunits are predominantly expressed in the cortex. These subunits are principally located in pyramidal cell dendrites, although they are also found at lower concentrations in the somata of pyramidal neurons as well as other neuron subtypes. HCN channels are actively trafficked to dendrites by binding to the chaperone protein TRIP8b. Somato‐dendritic HCN channels in pyramidal neurons modulate spike firing and synaptic potential integration by influencing the membrane resistance and resting membrane potential. Intriguingly, HCN channels are present in certain cortical axons and synaptic terminals too. Here, they regulate synaptic transmission but the underlying mechanisms appear to vary considerably amongst different synaptic terminals. In conclusion, HCN channels are expressed in multiple neuronal subcellular compartments in the cortex, where they have a diverse and complex effect on neuronal excitability.