Allodynia induced by regenerating axons is not positively correlated with degree of autotomy in the rat

We studied in the rat whether the incidence of autotomy correlated positive ly with severity of tactile allodynia induced by regenerating axons, Before transection and surgical repair of the sciatic nerve, the status of sensor y function was studied by stimulating mechanically the central part of the plantar paw with von Frey-hairs. Thereby we determined the threshold to evo ke the hindpaw withdrawal reflex. One and 2 months after the nerve transect ion and repair, the thresholds of the traumatized paws were lower than the pre-trauma thresholds. The contralateral paw withdrawal thresholds did not change during the follow-up time. The results indicated that regenerating a xons may cause tactile allodynia and that the severity of th is allodynia d oes not correlate positively with the incidence of autotomy. We found no co ntralateral allodynia after nerve transection and repair. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.