GDNF IS AN AGE-SPECIFIC SURVIVAL FACTOR FOR SENSORY AND AUTONOMIC NEURONS

Glial cell line-derived neurotrophic factor (GDNF) promotes the surviv al of two populations of CNS neurons: motoneurons and midbrain dopamin ergic neurons. To see whether GDNF promotes the survival of PNS neuron s, we studied embryonic chicken autonomic and sensory neurons in cultu re. We show that GDNF promotes the survival of sympathetic, parasympat hetic, proprioceptive, enteroceptive, and small and large cutaneous se nsory neurons. Whereas sympathetic, parasympathetic, and proprioceptiv e neurons become less responsive to GDNF with age, enteroceptive and c utaneous sensory neurons become more responsive. GDNF mRNA is expresse d in the tissues innervated by these neurons, and developmental change s in its expression in several tissues mirror the changing responses o f the innervating neurons to GDNF. These results show that GDNF promot es the survival of multiple PNS and CNS neurons and suggest that GDNF may be important for regulating the survival of various populations of neurons at different stages of their development.