The
neuropeptide galanin is widely expressed in both the central and peripheral nervous systems and is involved in many diverse
biological functions. There is a substantial data set that demonstrates
galanin is upregulated after injury in the DRG, spinal cord and in many brain regions where it plays a predominantly antinociceptive role in addition to being neuroprotective and pro-regenerative. To further characterise the role of
galanin following nerve injury, a novel transgenic line was created using the binary transgenic tet-off system, to overexpress
galanin in galaninergic tissue in a suppressible manner. The double transgenic mice express significantly more
galanin in the DRG one week after sciatic nerve section (
axotomy) compared to WT mice and this overexpression is suppressible upon administration of
doxycycline. Phenotypic analysis revealed markedly attenuated
allodynia when
galanin is overexpressed and an increase in
allodynia following
galanin suppression. This novel transgenic line demonstrates that whether
galanin expression is increased at the time of nerve injury or only after
allodynia is established, the
neuropeptide is able to reduce
neuropathic pain behaviour. These new findings imply that administration of a
galanin agonist to patients with established
allodynia would be an effective treatment for
neuropathic pain.