A neurotrophic substance emitted from smooth muscle and tissues innervated by neurons. Its role is thought to be the guidance of neuronal growth during embryonic development, especially in the peripheral nervous system, and in the maintenance of sympathetic and sensory neurons thereafter. In fact, it is crucial for thesurvival of sympathetic and sensory neurons, and when absent these neurons aresubject to apoptosis. Neurotrophinsactually form a family that includes, for example, Brain-derived neurotrophicFactor (BDNF), Glial-derived neurotrophic factor (GDNF) and neurotropin-3(NT-3). Such factors regulate andpromote the growth of a variety of different neurons such as those concernedwith protein synthesis and the manufacture of neurotransmitters (e.g.,dopaminergic neurons in the substantia nigra, the demise of which results inParkinson’s disease). Becauseneurotrophic factors promote neuron growth and survival, they are seen aspotential therapeutic agents in, for example, the management of pain and in thetreatment of neurodegenerative diseases such Parkinsonism and Alzheimer’s. Another function associated with NGF wasevident in a study of novice parachute jumpers. Both before and after jumping, there was a marked increase in bloodplasma NGF levels, prior to increases in plasma cortisol, suggesting that theyserve also as a marker of stress or anxiety-inducing situations. NGF was discovered in the 1960s by RitaLevi-Montalcini (1909-2012) and Stanley Cohen for which they were jointly awardedthe Nobel Prize for Physiology and Medicine in 1986. Apparently, Levi-Montalcini used NGF as eyedrops on a daily basis.
See Apoptosis (or cell death), Alzheimer’s disease, Axon retraction (orpruning), Basal ganglia (anatomy), Brain-Derived Neurotrophic Factor (BDNF), Cortisol, Glial-derived neurotrophic factor (GDNF), Growth factors, Neurite, Neurotransmitters, Parkinson’s disease, Peripheral nervous system, Polyneural to mononeural innervation, Sympathetic nervous system (SNS), Stress (or adrenal) hormones