The NaVy paradox: reducing sodium currents increases excitability.

Mutations that increase sodium currents in excitatory neurons typically produce hyperexcitability and epileptic seizures. Paradoxically, mutations that reduce NaV1.2 sodium currents also have a similar effect. Two research groups (Spratt et al. and Zhang et al.) have now found that in some excitatory neurons, loss of NaV1.2 increases intrinsic excitability by altering activation and/or expression of potassium channels.