Nicotinic acetylcholine receptors and epilepsy

The neuronal nicotinic acetylcholine receptors (nAChRs) have multiple roles in the brain: they are involved in signal transduction by fast synaptic transmission, axo-axonic transmission, and in the modulation of presynaptic transmitter release. Presynaptic nAChRs can increase the release of excitatory as well as of inhibitory transmitters, and can thereby control neuronal excitability. Furthermore, nAChRs which are expressed in fetal brain might also be involved in brain morphogenesis. Thus, the genes coding for the different nAChR subunits are likely candidates for several neurological disorders. The CHRNA4- or CHRNB2 subunits of the nAChR are associated with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), a rare monogenic type of idiopathic epilepsy. Electrophysiological studies demonstrated that ADNFLE mutations are causing both a loss-of-function and a gain-of-function in alpha4/beta2-heteropentameric nAChRs.