MOLECULAR-CLONING OF A NONINACTIVATING PROTON-GATED NA+ CHANNEL SPECIFIC FOR SENSORY NEURONS

We have cloned and expressed a novel proton-gated Na+ channel subunit that is specific for sensory neurons. In COS cells, it forms a Na+ cha nnel that responds to a drop of the extracellular pH with both a rapid ly inactivating and a sustained Na+ current, This biphasic kinetic clo sely resembles that of the H+-gated current described in sensory neuro ns of dorsal root ganglia (1). Both the abundance of this novel H+-gat ed Na+ channel subunit in sensory neurons and the kinetics of the chan nel suggest that it is part of the channel complex responsible for the sustained H+-activated cation current in sensory neurons that is thou ght to be important for the prolonged perception of pain that accompan ies tissue acidosis (1, 2).