Potential therapeutic mechanism of K+ channel block for MS

► 4-AP shows clinical utility in treating walking disability in MS. ► KV1 and KV3 voltage-gated K+ channel sub-types, expressed in axons, are blocked by 4-AP. ► 4-AP targets K+ channels on the basis of channel molecular structure and membrane potential. ► Pre-synapse activation probability is increased by systemic 4-AP.