The role of neurotrophins in axonal growth, guidance, and regeneration

[Guest guest]

Curr Neurovasc Res. 2007 May;4(2):143-51.

The role of neurotrophins in axonal growth, guidance, and

regeneration.

Lykissas MG, Batistatou AK, Charalabopoulos KA, Beris AE.

Department of Orthopaedics, Ioannina University Medical School,

Ioannina, Greece.

Neurotrophins are proteins that regulate neuronal survival, axonal

growth, synaptic plasticity and neurotransmission. They are members

of the neurotrophic factors family and include factors such as the

nerve growth factor (NGF), the brain derived neurotrophic factor

(BDNF), the neurotrophin-3 (NT-3), and the neurotrophin-4/5 (NT-

4/5).

These molecules bind to two types of receptors: i) tyrosine kinase

receptors (TrkA, TrkB, TrkC) and ii) a common neurotrophin receptor

(p75NTR). The two receptor types can either suppress or enhance each

other's actions.

Neurotrophins have a multifunctional role both in the central and

peripheral nervous system. They have been suggested as axonal

guidance molecules during the growth and regeneration of nerves. It

has also been proven that they stimulate axonal growth by mediating

the polymerization and accumulation of F-actin in growth cones and

axon shafts.

Neurotrophins, as other neurotrophic factors, have been shown that

they reduce neuronal injury by exposure to excitotoxins, glucose

deprivation, or ischemia. Furthermore, the nerve regeneration

promoting effect of these growth factors is well documented for many

different models of central or peripheral nervous system injury.

Several studies have shown that exogenous administration of these

factors has protective properties for injured neurons and stimulates

axonal regeneration.

Based on these properties, these molecules may be used as

therapeutic agents for treating degenerative diseases and traumatic

injuries of both the central and peripheral nervous system.