Involvement of Na+ channels in pain pathways

Voltage-dependent Na+ channels in sensory nerves contribute to the control of membrane excitability and underlie action potential generation. Na+ chan nel subtypes exhibit a neurone-specific and developmentally regulated patte rn of expression, and changes in both channel expression and function are c aused by disease. Recent evidence implicates specific roles for Na+ channel subtypes Na(v)1.3 and Na(v)1.8 in pain states that are associated with ner ve injury and inflammation, respectively. Insight into the role of Na(v)1.8 in pain pathways has been gained by the generation of a null mutant. Altho ugh drugs discriminate poorly between subtypes, the molecular diversity of channels and subtype-specific modulation might provide opportunities to tar get pain pathways selectively.