BDNF is upregulated in injured DRG neurons suggesting a role for this neurotrophin in their regeneration. We reported previously that antagonizing endogenous BDNF results in reduced expression of injury/regeneration-associated genes believed to underly the high capacity for regeneration in these neurons (Geremia et al., 2003 SfN Abstr 38.4). The present study investigates the role of BDNF in modulating neurite outgrowth of injured sensory neurons and the possible intracellular signaling pathways it might regulate as part of the regenerative response. Male Wistar rats underwent unilateral L4,5,6 spinal nerve lesions with anti-BDNF delivered intrathecally for the duration of the 3d injury. Control antibody (Sheep IgG) infusion or spinal nerve injury alone served as controls. L4,5 DRG were removed and cultured in serum free media for 24hrs on laminin and poly-L-lysine coated plates. Injury alone resulted in the highest degree of neurite outgrowth when compared to uninjured neurons. Anti-BDNF infusion resulted...