Ectopic discharge in Abeta afferents as a source of neuropathic pain.

Ectopic discharge in axotomized dorsal root ganglion neurons is a key driver of neuropathic pain. However, the bulk of this activity is generated and carried centrally in large diameter myelinated Abeta afferents, a cell type that normally signals touch and vibration sense. Evidence is considered suggesting that following axotomy, Abeta afferents undergo a change in their electrical characteristics and also in the neurotransmitter complement that they express. This dual phenotypic switching renders them capable of (1) directly driving postsynaptic pain signaling pathways in the spinal cord, and (2) triggering and maintaining central sensitization.