Neurotrophins are a family of molecules that encourage survival of nervous tissue. Neurotrophic factors are secreted by cells in a neuron's target field, and act by prohibiting the neuron from apoptosis. In this way, target neurons are not removed. Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... A cell undergoing apoptosis. ...

The neurotrophin family include the growth factors Nerve Growth Factor (NGF), Brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), and neurotrophin 4 (NT-4). There are two classes of receptors, p75 and the "Trk" family of Tyrosine kinases receptors. p75 is a low affinity neurotrophin receptor, to which all neurotrophins bind. The Trk family include TrkA, TrkB, and TrkC, and will only bind with specific neurotrophins, but with a much higher affinity. The Trks mediate the functional signals of the neurotrophins. Nerve growth factor (NGF), the prototypical growth factor, is a protein secreted by a neurons target. ... NGF may refer to Nerve growth factor Naval gunfire, see naval gunfire support This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Brain-derived neurotrophic factor (BDNF) is exactly as it states; a neurotrophic factor usually derived in the brain. ... Neurotrophin-3, or NT-3 is a neurotrophic factor, in the NGF (Nerve Growth Factor)-family of neurotrophins. ... Tyrosine kinases are a subclass of protein kinase, see there for the principles of protein phosphorylation A tyrosine kinase (EC 2. ... The Low Affinity Nerve Growth Factor Receptor (also called the LNGFR or p75 neurotrophin receptor) is one of the two receptor-types for the neurotrophins, a family of protein growth factors which stimulate neuronal cells to survive and differentiate. ... // TrkA is the high affinity receptor for the neurotrophin, Nerve Growth Factor, or NGF. As such, it mediates the multiple effects of NGF, which includes neuronal differentiation and survival. ... // Function TrkB is the high affinity receptor for several neurotrophins, which are small protein growth factors that induce the survival and differentiation of distinct cell populations. ... // TrkC is the high affinity receptor for the neurotrophin NT-3 (neurotrophin-3). ...

Nerve Growth Factor, NGF

Nerve growth factor (NGF), the prototypical growth factor, is a protein secreted by a neuron's target. NGF is critical for the survival and maintenance of sympathetic and sensory neurons. NGF is released from the target cells, binds to and activates its high affinity receptor (TrkA), and is internalized into the responsive neuron. The NGF/TrkA complex is subsequently trafficked back to the cell body. This movement of NGF from axon tip to soma is thought to be involved in the long-distance signaling of neurons. NGF may refer to Nerve growth factor Naval gunfire, see naval gunfire support This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Growth factor is a protein that acts as a signaling molecule between cells (like cytokines and hormones) that attaches to specific receptors on the surface of a target cell and promotes differentiation and maturation of these cells. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... NGF may refer to Nerve growth factor Naval gunfire, see naval gunfire support This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... The mechanism of the reflex arc Sensory neurons (or neurones) are nerve cells within the nervous system responsible for converting external stimuli from the organisms environment into internal [[electrical poop is responsible for it aright underlie motor reflex loops and several forms of involuntary behavior, including pain avoidance. ... Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... NGF may refer to Nerve growth factor Naval gunfire, see naval gunfire support This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Target cells are the sites where hormones act. ... // TrkA is the high affinity receptor for the neurotrophin, Nerve Growth Factor, or NGF. As such, it mediates the multiple effects of NGF, which includes neuronal differentiation and survival. ... NGF may refer to Nerve growth factor Naval gunfire, see naval gunfire support This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... // TrkA is the high affinity receptor for the neurotrophin, Nerve Growth Factor, or NGF. As such, it mediates the multiple effects of NGF, which includes neuronal differentiation and survival. ... The soma is the bulbous end of a neuron, containing the nucleus. ... NGF may refer to Nerve growth factor Naval gunfire, see naval gunfire support This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... The soma is the bulbous end of a neuron, containing the nucleus. ...

Brain-derived Neurotrophic Factor, BDNF

Brain-derived neurotrophic factor (BDNF) is a neurotrophic factor found originally in the brain, but also found in the periphery. More specifically, it is a protein which has activity on certain neurons of the central nervous system and the peripheral nervous system; it helps to support the survival of existing neurons, and encourage the growth and differentiation of new neurons and synapses through axonal and dendritic sprouting. In the brain, it is active in the hippocampus, cortex, cerebellum, and basal forebrain—areas vital to learning, memory, and higher thinking. BDNF was the second neurotrophic factor to be characterized, after nerve growth factor (NGF) and before neurotrophin three (NT-3). Brain-derived neurotrophic factor (BDNF) is exactly as it states; a neurotrophic factor usually derived in the brain. ... Neurotrophins are a family of molecules that encourage survival of nervous tissue. ... In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... A diagram showing the CNS: 1. ... Illustration of the major elements in a prototypical synapse. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, which conducts electrical impulses away from the neurons cell body or soma. ... The hippocampus is located in the medial temporal lobe of the brain. ... Location of the cerebral cortex Slice of the cerebral cortex, ca. ... In the anatomy of vertebrates, the prosencephalon is a part of encephalon, or brain. ... Brain-derived neurotrophic factor (BDNF) is exactly as it states; a neurotrophic factor usually derived in the brain. ... NGF may refer to Nerve growth factor Naval gunfire, see naval gunfire support This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Neurotrophin-3, or NT-3 is a neurotrophic factor, in the NGF (Nerve Growth Factor)-family of neurotrophins. ...

Although the vast majority of neurons in the mammalian brain are formed prenatally, parts of the adult brain retain the ability to grow new neurons from neural stem cells; a process known as neurogenesis. Neurotrophins are chemicals that help to stimulate and control neurogenesis, BDNF being one of the most active. Mice born without the ability to make BDNF suffer developmental defects in the brain and sensory nervous system, and usually die soon after birth, suggesting that BDNF plays an important role in normal neural development. Orders Multituberculata (extinct) Volaticotheria (extinct) Palaeoryctoides (extinct) Triconodonta (extinct) Subclass Australosphenida Ausktribosphenida Monotremata Subclass Eutheria (excludes extinct ancestors) Afrosoricida Anagaloidea (extinct) Arctostylopida (extinct) Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Cingulata Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Dinocerata (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Leptictida (extinct) Litopterna (extinct) Macroscelidea Mesonychia... Mouse embryonic stem cells with fluorescent marker. ... Neurogenesis (birth of neurons) is the process by which neurons are created. ... Brain-derived neurotrophic factor (BDNF) is exactly as it states; a neurotrophic factor usually derived in the brain. ... The study of neural development draws on both neuroscience and developmental biology to describe the cellular and molecular mechanisms by which complex nervous systems emerge during embryonic development and throughout life. ...

Despite its name, BDNF is actually found in a range of tissue and cell types, not just the brain. Expression can be seen in the retina, the CNS, motor neurons, the kidneys, the prostate and post-katiemorgan circuit. Brain-derived neurotrophic factor (BDNF) is exactly as it states; a neurotrophic factor usually derived in the brain. ...

Neurotrophin-3, NT-3

Neurotrophin-3, or NT-3 is a neurotrophic factor, in the NGF (Nerve Growth Factor)-family of neurotrophins. It is a protein growth factor which has activity on certain neurons of the peripheral and central nervous system; it helps to support the survival and differentiation of existing neurons, and encourages the growth and differentiation of new neurons and synapses. NT-3 was the third neurotrophic factor to be characterized, after nerve growth factor (NGF) and BDNF (Brain Derived Neurotrohic Factor). Neurotrophin-3, or NT-3 is a neurotrophic factor, in the NGF (Nerve Growth Factor)-family of neurotrophins. ... Neurotrophin-3, or NT-3 is a neurotrophic factor, in the NGF (Nerve Growth Factor)-family of neurotrophins. ... Neurotrophins are a family of molecules that encourage survival of nervous tissue. ... Neurotrophins are a family of molecules that encourage survival of nervous tissue. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Growth factor is a protein that acts as a signaling molecule between cells (like cytokines and hormones) that attaches to specific receptors on the surface of a target cell and promotes differentiation and maturation of these cells. ... Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ... A diagram showing the CNS: 1. ... Illustration of the major elements in a prototypical synapse. ... Neurotrophin-3, or NT-3 is a neurotrophic factor, in the NGF (Nerve Growth Factor)-family of neurotrophins. ... Nerve growth factor (NGF), the prototypical growth factor, is a protein secreted by a neurons target. ... NGF may refer to Nerve growth factor Naval gunfire, see naval gunfire support This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Brain-derived neurotrophic factor (BDNF) is exactly as it states; a neurotrophic factor usually derived in the brain. ...

Although the vast majority of neurons in the mammalian brain are formed prenatally, parts of the adult brain retain the ability to grow new neurons from neural stem cells; a process known as neurogenesis. Neurotrophins are chemicals that help to stimulate and control neurogenesis. NT-3 is unique in the number of neurons it can potentially stimulate, given its ability to activate two of the receptor tyrosine kinase neurotrophin receptors (TrkC and TrkB - see below). Mice born without the ability to make NT-3 have loss of proprioceptive and subsets of mechanoreceptive sensory neurons. Orders Multituberculata (extinct) Volaticotheria (extinct) Palaeoryctoides (extinct) Triconodonta (extinct) Subclass Australosphenida Ausktribosphenida Monotremata Subclass Eutheria (excludes extinct ancestors) Afrosoricida Anagaloidea (extinct) Arctostylopida (extinct) Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Cingulata Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Dinocerata (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Leptictida (extinct) Litopterna (extinct) Macroscelidea Mesonychia... Mouse embryonic stem cells with fluorescent marker. ... Neurogenesis (birth of neurons) is the process by which neurons are created. ... Neurotrophin-3, or NT-3 is a neurotrophic factor, in the NGF (Nerve Growth Factor)-family of neurotrophins. ... // TrkC is the high affinity receptor for the neurotrophin NT-3 (neurotrophin-3). ... // Function TrkB is the high affinity receptor for several neurotrophins, which are small protein growth factors that induce the survival and differentiation of distinct cell populations. ... Neurotrophin-3, or NT-3 is a neurotrophic factor, in the NGF (Nerve Growth Factor)-family of neurotrophins. ...

Neurotrophin-4, NT-4

NT-4, like (BDNF) is a neurotrophic factor that signals predominantly through the TrkB receptor tyrosine kinase. Brain-derived neurotrophic factor (BDNF) is exactly as it states; a neurotrophic factor usually derived in the brain. ... Neurotrophins are a family of molecules that encourage survival of nervous tissue. ... // Function TrkB is the high affinity receptor for several neurotrophins, which are small protein growth factors that induce the survival and differentiation of distinct cell populations. ... The receptor tyrosine kinase (RTK) family of cell surface receptors shows a high affinity to numerous growth signals. ...

References

[1] "Neurotrophin signaling: many exciting surprises!", Cell Mol Life Sci. 2006 May 15; [Epub ahead of print]

[2] "Dissecting the diverse actions of pro- and mature neurotrophins", Curr Alzheimer Res. 2006 Feb;3(1):19-24.

[3] "Clinical relevance of the neurotrophins and their receptors", Clin Sci (Lond). 2006 Feb;110(2):175-91.

External links

• DevBio.com - 'Neurotrophin Receptors: The neurotrophin family consists of four members: nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), and neurotrophin 4 (NT-4)' (April 4, 2003)
• Dr.Koop.com - 'New Clues to Neurological Diseases Discovered: Findings could lead to new treatments, two studies suggest', Steven Reinberg, HealthDay (July 5, 2006)
• Helsinki.fi - 'Neurotrophic factors'