Pharmacology of chronic pain

Chronic pain, which is associated with prolonged tissue damage or injuries to the peripheral or central nervous system, results from a number of compl ex changes in nociceptive pathways. These include alterations of cell pheno type and changes in the expression of proteins such as receptors, transmitt ers, and ion channels, as well as modifications of neural structure, for ex ample, cell loss, nerve regeneration, and synaptic reorganizations. The res ultant increase in neural excitability can be reduced with receptor-selecti ve drugs that block peripheral or central chemical mediators or that Contro l ectopic activity or cellular phenotype changes. In this article, Andy Dra y, Laszlo Urban, and Anthony Dickenson focus on some current mechanistic as pects of chronic pain imposed by inflammation and peripheral neuropathy, an d review, in particular, the molecular changes involving the pharmacology o f nociceptive pathways, since these have important implications for the man agement of pain.