Spinal nerve injury increases the percentage of cold-responsive DRG neurons.

We tested the hypothesis that cold allodynia, observed following nerve injury reflects change(s) in the cold responsiveness of sensory neurons. To test this hypothesis we assessed the impact of the spinal nerve ligation (SNL) model of nerve injury on the responses of cutaneous sensory neurons to cooling in vitro. Nerve injury induced a significant increase in the incidence of cold responsive cutaneous neurons in uninjured but not injured ganglia. Because an increase in the percentage of cold responsive neurons in uninjured ganglia should increase the total neuronal response to cooling of peripheral tissue, these findings suggest that cold allodynia reflects, at least in part, a change in sensory neurons.