Ezogabine

Ezogabine has a novel mechanism of action that involves opening of neuronal Kv7.2-7.5 (formerly KCNQ2-5) voltage activated potassium channels. These channels (primarily Kv7.2/7.3) enable generation of the M-current, a sub-threshold potassium current that serves to stabilize the membrane potential and control neuronal excitability. In addition to acting on potassium ion channels, retigabine also affects GABA neurotransmission in the GABA-A receptor, which is a key inhibitory receptor in the central nervous system and is implicated in epilepsy. Malfunctioning of the GABA-A receptor leads to hyperexcitability in the brain, which causes seizures, making this receptor an important target for antiepileptic therapeutics. Apart from increasing the concentration of GABA in the brain (by either enhancing GABA synthesis or blocking GABA metabolism), retigabine allosterically potentiates GABA-induced current in rat cortical neurons in a concentration-dependent manner. Numerous studies have demonstrated that retigabine is effective in a broad spectrum of in vivo epilepsy and seizure models.