Changes in post-tetanic potentiation of A-fiber dorsal horn field potentials parallel the development and disappearance of neuropathic pain after sciatic nerve ligation in rats

Significant plastic changes in spinal nociceptive processing appear to acco mpany peripheral nerve injury or inflammation. Using a well-established mod el of neuropathic pain, we have recently reported that loose ligation of th e sciatic nerve was accompanied by a long-lasting post-tetanic potentiation of sciatic-evoked A-fiber superficial dorsal horn field potentials. In the present study we demonstrate that the typical disappearance of thermal hyp eralgesia as a behavioral sign of neuropathic pain several weeks after loos e sciatic nerve ligation is accompanied by the loss of the long-lasting pot entiation. These data suggest that a significant but reversible shift in th e processing of sensory information in the spinal dorsal horn follows perip heral nerve injury, and lend further support to the notion that long-lastin g synaptic plasticity may contribute to the development of neuropathic pain . (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.