[Neurotrophins as a therapeutic tool for degenerative neuronal disorders]

Nerve growth factor (NGF) is the prototype of a family of structurally related neurotrophic factors, named as neurotrophins, that also include brain-derived neurotrophic factor (BDNF), neurotrophin (NT)-3, NT-4 and NT-5. NGF is known to support the development and maintenance of sympathetic and neural crest-derived sensory neurons in the peripheral nervous system (PNS). In the central nervous system (CNS), NGF stimulates the survival of basal forebrain cholinergic neurons both in vivo and vitro. BDNF supports the survival of much wider types of neurons including nodose ganglion sensory neurons in the PNS, spinal motoneurons, basal forebrain cholinergic neurons and mesencephalic dopaminergic neurons in the CNS in culture. Pathophysiological observations and complementary animal experiments suggest the possible use of neurotrophins as therapeutic tools for degenerative neuronal disorders. However, applications of neurotrophins are macromolecules that cannot pass through the blood-brain barrier. Also, it is not possible to produce them in a large scale. In view of this, facilitatory measures to enhance neurotrophin production by either pharmacological or medical means are possible promising approaches in employing neurotrophin functions as a therapy. I described here a successful result that pharmacological induction of NGF and BDNF enhanced sprouting of nerve fibers from proximal site of transected rat sciatic nerve.