Abstract
To reveal roles of neurotrophic factors in plastic
changes of the primary afferent neurons following
nerve injury, we investigated expression of glial cell
line-derived neurotrophic factor (GDNF) as well as
nerve growth factor (NGF) in a neuropathic pain
model of the rat. The rats exhibited hyperalgesia
and allodynia on the injured left side for at least 2
weeks after chronic constrictive injury to the sciatic
nerve. Accompanied by the behavioral
changes, expression of GDNF decreased in the
dorsal root ganglia (DRGs) and the sciatic nerve on
the injured side on the fourteenth day after the
surgery. In contrast, the amount of NGF in DRGs
was unchanged in spite of disturbance of NGF
transport in the nerve. The present results suggest
that decreased expression of GDNF takes some
part in development and/or maintenance of neuropathic
pain.
