Transgenic over-expression of galanin in injured primary sensory neurons.

The 29 amino acid neuropeptide galanin is normally expressed in < 5% of sensory neurons in the adult dorsal root ganglia. After nerve transection (axotomy), the galanin content of the dorsal root ganglia rises 120-fold and the peptide is then expressed in > 50% of neurons. Published data suggest that galanin plays a role in the modulation of pain processing and may be involved in the regeneration of sensory neurons. Here we describe the initial characterisation of a new line of transgenic mice that selectively over-express galanin in the dorsal root ganglia in an inducible manner following axotomy of the sciatic nerve, but not in the uninjured state. Results of acute thermal or mechanosensory pain tests are normal in intact transgenic animals when compared to wild-type controls. The generation of these novel transgenic animals will be most useful as genetic tools to further elucidate the role played by galanin in the adaptive response of the peripheral nervous system to injury.