Role of gap junctions in chronic pain.

Gap junctions are specialized transmembrane channels that allow rapid electrical signalling and direct intercellular communication for maintenance and coordination of normal cellular activities and homeostasis. Although gap junction channels in the nervous system mediate intercellular coupling between glial cells and between neurons, they also contribute to the spread of secondary damage and inflammation under pathological conditions. There is now evidence of the involvement of gap junctions in chronic pain caused by nervous system damage or tissue inflammation. In this Mini-Review, we highlight recent studies demonstrating the dynamic plasticity of gap junctions in response to nervous system injury and the effects of gap junction blockade on neuronal survival and modulation of pain in animal models of neuropathic and inflammatory pain. The involvement of dorsal root ganglia and spinal cord gap junctions in mediating chronic pain and the potential for targeting connexins as a novel modality for the treatment of intractable pain syndromes arising from nervous system injury and disorders are discussed.