LONG-TERM SURVIVAL EFFECTS OF GDNF ON NEONATAL RAT FACIAL MOTONEURONSAFTER AXOTOMY

GLIAL cell-line derived neurotrophic factor (GDNF) has survival promot ing effects on axotomized neonatal motoneurons. We examined how long i t could sustain motoneurons after postnatal day 0 (PND) facial nerve a xotomy. GDNF, or cytochrome c as a negative control, were locally admi nistered by Gelfoam implants at the time of axotomy and some were re-i mplanted on PND 14. The surviving motoneurons were quantified on PND 1 4 and 28. GDNF completely rescued lesioned motoneurons from axotomy-in duced cell death at 14 days and was still effective (about 40%) at PND 28. GDNF also prevented axotomy-induced atrophy at both PND 14 and 28 , indicating that the neurotrophic effects of GDNF on neonatal motoneu rons are long-term.