Table 1.

The use of GFs and their effect on CNS and PNS (Terenghi, 1999).

Neurotrophic factor	Neural response	Receptor and action
NGF	Sensory neuron survival Sensory neuron outgrowth Spinal cord regeneration	TrkA/p75, receptors expressed in sympathetic/peripheral sensory neurons (Schwann cells upregulate NGF and p75 in response to PNS injury); Involved in survival signaling and neurite outgrowth;
GDNF	Motor neuron survival Motor neuron outgrowth Sensory neuron survival	GFRa/Ret, receptors expressed in sensory/motor neurons, GDNF primarily produced by Schwann cells in development and plays an important role in sensory regeneration;
BDNF	Motor neuron survival Motor neuron outgrowth Sensory neuron outgrowth	TrkB, BDNF mRNA upregulated in distal nerve stump after sciatic nerve transection; positive modulation of peripheral nerve myelination;
CNTF	Motor neuron survival Motor neuron outgrowth Spinal cord regeneration	CNTFR, present in peripheral nerves and myelinating Schwann cells; promotes survival of motor neurons;
NT-3	Motor neuron survival Motor neuron outgrowth Sensory neuron outgrowth Spinal cord regeneration	TrkC, NT-3 mRNA downregulated in distal nerve stump after sciatic nerve transection; negative modulation of peripheral nerve myelination;
NT4/5	Motor neuron survival Motor neuron outgrowth Sensory neuron survival	TrkB, plays a role in survival of adult sensory neurons;
FGF-2	Motor neuron survival Motor neuron outgrowth Sensory neuron survival Spinal cord regeneration Peripheral nerve regeneration	FGFR1-3 plays a role in regeneration of motor and sensory neurons, as well as in myelination.