Kv3.1 mRNA is abundantly expressed in auditory brain stem neurons that are able to spike at high frequencies. It has a high threshold of activation and rapid activation/deactivation kinetics. Evidence for functional Kv3.1 activity in such neurons can be derived from the rapidly activating and deactivating potassium currents seen here, that activate at a high-voltage threshold similar to that of heterologously expressed Kv3.1. There are indications that the phosphorylation state in rat Kv3.1 may play a part in the ability of auditory neurons to adjust to the ambient acoustic environment. It is thought that Kv3.1 subunits are likely to form homomultimers in lymphocytes and therefore could be a target for the development of novel immunosuppresants.