Jun N-terminal kinase's role in neuropathic pain: C-fiber remodeling and growth-associated protein-43 phosphorylation

PNI significantly increased pGAP-43 and pJNK in largely overlapping dorsal root ganglion neurons. In the dorsal horn ipsilateral to the injury, pGAP-43-positive terminals colocalized with L1-CAM-labeled axonal varicosities in laminae I-II. Chronic intrathecal JNK inhibition alleviated neuropathic pain and reduced pGAP-43 immunoreactivity in axon terminals, also preventing injury-induced hypertrophy of L1-CAM-labeled varicosities in the dorsal horn.