Inhibition. We usually like to think of GABA as an inhibitory neurotransmitter, which counteracts the excitatory and potentially epileptogenic effects of glutamate. However, this is not always true during brain development. Initially, GABA is a powerful excitatory neurotransmitter. The excitatory effect of GABA has been shown to be important for brain development and the formation of dendritic spines – and the switch from excitation to inhibition is due to a single ion channel: KCC2, encoded by SLC12A5. Two recent publications in EMBO Reports now implicate genetic variation in SLC12A5 in human epilepsy. Continue reading →