Galanin plays a role in the conditioning lesion effect in sensory neurons.

Sensory neurons show enhanced neurite outgrowth in vivo and in vitro following a conditioning lesion. Previous studies have shown that these effects are dependent on two members of the gp130 family of cytokines, leukemia inhibitory factor and interleukin-6. Here, we asked whether galanin, a neuropeptide induced by these cytokines, plays a role in the conditioning lesion response. Following a conditioning lesion, neurite outgrowth in culture was reduced in sensory neurons from galanin -/- mice compared with those from wild type controls. In neurons from wild type mice, the length of the longest neurite was increased 2.4-fold after a conditioning lesion, compared with 1.8-fold in neurons from knockout animals. The results indicate that the induction of galanin plays an important role in triggering the conditioning lesion response.