Table 3.
Channel/current | Form of epilepsy | Nature of change | Impact on cell excitability | Reference |
---|---|---|---|---|
HCN channel/ HCN current Ih | Temporal lobe epilepsy (TLE) | Sustained reduction in current density following status epilepticus (SE) induction | Enhanced pyramidal and interneuron excitability | Dugladze et al. 2007; Jung et al. 2007; Marcelin et al. 2009; Shah et al. 2004; Shah et al. 2012; Shin et al. 2008; Wierschke et al. 2010 |
HCN channels/ HCN current Ih | Febrile seizure-induced epilepsy | Enhanced HCN channel expression and current | Enhanced rebound activity following inhibitory post-synaptic potentials (IPSPs) | Bender et al. 2003; Chen et al. 2001; Dyhrfjeld-Johnsen et al. 2008 |
HCN current Ih | Fragile X syndrome | Enhanced HCN channel current | Impaired long-term potentiation (LTP in pyramidal neurons) | Brager et al. 2012 |
CaV3.2 channels/ T-type Ca2+ current | TLE | Transient elevation of expression and current from SE to chronic epilepsy | Enhanced pyramidal cell bursting | Becker et al. 2008; Su et al. 2002 |
KV4.2 channels/ A-type K+ current | TLE | Reduction 1 week after SE and persisting during chronic TLE | Enhanced pyramidal cell dendritic excitability | Bernard et al. 2004; Monaghan et al. 2008 |
BK channels | TLE | Reduction in expression during chronic TLE | ?? | Pacheco Otalora et al. 2008 |
Kir2 channels/ inward rectifier current | Chronic TLE | Enhanced expression | Reduced dentate gyrus granule cell excitability | Young et al. 2009 |
KCNN1 (SK1) KCNN2 (SK2) and KCNN3 (SK3) channels | TLE | Transient reduction during chronic TLE | Increased number of hippocampal population spikes | Oliveira et al. 2010 |
Persistent sodium current | TLE | Sustained increase following SE | Enhanced neuronal excitability | Agrawal et al. 2003; Chen et al. 2011; Epsztein et al. 2010; Hargus et al. 2011; Vreugdenhil et al. 2004 |
Full references can be found in Supplementary information. The neuronal localization of some of the channel proteins is shown in Figure 1.