The nerve growth factor (NGF) is a type of protein molecule that stimulates the growth and maintenance of sympathetic and sensory neurons and is essential for their survival. The nerve growth factor consists of three types of polypeptide chains: alpha, beta, and gamma, which interact to constitute the protein molecule, with the beta chain being responsible for axonal growth. The NGF binds with at least two classes of receptors: the p75 LNGFR neurotrophin receptor (p75(NTR)) and TrkA, a transmembrane tyrosine kinase. LNGFR stands for "low-affinity nerve growth factor receptor". Recent findings suggest that it is a very important mediator of inflammation, in particular in the airways.
The nerve growth factor belongs to the family of neurotrophins, which is secreted by neurons's target cells. It was discovered 50 years ago as a molecule that promoted the survival and differentiation of sensory and sympathetic neurons. NGF has the potential to help treat several diseases of the nervous system. It has shown this through numerous clinical trials. It has been shown to reduce neural degeneration. It has also been shown to promote peripheral nerve regeneration in rats.