Ectopic discharge in Aβ afferents as a source of neuropathic pain

Abstract

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 Aβ afferents, a cell type that normally signals touch and vibration sense. Evidence is considered suggesting that following axotomy, Aβ 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. © 2009 Springer-Verlag.