GDNF MESSENGER-RNA IN SCHWANN-CELLS AND DRG SATELLITE CELLS AFTER CHRONIC SCIATIC-NERVE INJURY

GLIAL cell line-derived neurotrophic factor (GDNF) exhibits neurotroph ic properties on different types of neurones, including fetal motoneur ones and embryonic neurones of sensory ganglia. We demonstrate that ch ronic injury to the adult rat sciatic nerve induces a rapid up-regulat ion of GDNF mRNA expression in Schwann cells proximal as well as dista l to the injury site, and that expression of this mRNA remains at high levels for at least 5 months after injury. In addition, GDNF mRNA inc reases and remains high in satellite cells and Schwann cells of the af fected L4/L5 DRGs. These findings suggest that GDNF is an important fa ctor in the events that follow upon adult chronic primary sensory neur one injury, and possibly also after adult motoneurone axotomy.