|
Excitatory Amino Acid Transporter
Glutamate transporters are a family of neurotransmitter transporter proteins that move glutamate – the principal excitatory neurotransmitter – across a membrane. The family of glutamate transporters is composed of two primary subclasses: the excitatory amino acid transporter (EAAT) family and vesicular glutamate transporter (VGLUT) family. In the brain, EAATs remove glutamate from the synaptic cleft and extrasynaptic sites via glutamate reuptake into glial cells and neurons, while VGLUTs move glutamate from the cell cytoplasm into synaptic vesicles. Glutamate transporters also transport aspartate and are present in virtually all peripheral tissues, including the heart, liver, testes, and bone. They exhibit stereoselectivity for L-glutamate but transport both L-aspartate and D-aspartate. The EAATs are membrane-bound secondary transporters that superficially resemble ion channels. These transporters play the important role of regulating concentrations of glutamate in the extracell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotransmitter Transporter
Neurotransmitter transporters are a class of membrane transport proteins that span the cellular membranes of neurons. Their primary function is to carry neurotransmitters across these membranes and to direct their further transport to specific intracellular locations. There are more than twenty types of neurotransmitter transporters. Vesicular transporters move neurotransmitters into synaptic vesicles, regulating the concentrations of substances within them. Vesicular transporters rely on a proton gradient created by the hydrolysis of adenosine triphosphate (ATP) in order to carry out their work: v-ATPase hydrolyzes ATP, causing protons to be pumped into the synaptic vesicles and creating a proton gradient. Then the efflux of protons from the vesicle provides the energy to bring the neurotransmitter into the vesicle. Neurotransmitter transporters frequently use electrochemical gradients that exist across cell membranes to carry out their work. For example, some transporters use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excitotoxicity
In excitotoxicity, nerve cells suffer damage or death when the levels of otherwise necessary and safe neurotransmitters such as glutamate become pathologically high, resulting in excessive stimulation of receptors. For example, when glutamate receptors such as the NMDA receptor or AMPA receptor encounter excessive levels of the excitatory neurotransmitter, glutamate, significant neuronal damage might ensue. Excess glutamate allows high levels of calcium ions (Ca2+) to enter the cell. Ca2+ influx into cells activates a number of enzymes, including phospholipases, endonucleases, and proteases such as calpain. These enzymes go on to damage cell structures such as components of the cytoskeleton, membrane, and DNA. In evolved, complex adaptive systems such as biological life it must be understood that mechanisms are rarely, if ever, simplistically direct. For example, NMDA in subtoxic amounts induces neuronal survival of otherwise toxic levels of glutamate. Excitotoxicity may be inv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrochemical Gradient
An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts, the chemical gradient, or difference in solute concentration across a membrane, and the electrical gradient, or difference in charge across a membrane. When there are unequal concentrations of an ion across a permeable membrane, the ion will move across the membrane from the area of higher concentration to the area of lower concentration through simple diffusion. Ions also carry an electric charge that forms an electric potential across a membrane. If there is an unequal distribution of charges across the membrane, then the difference in electric potential generates a force that drives ion diffusion until the charges are balanced on both sides of the membrane. Electrochemical gradients are essential to the operation of batteries and other electrochemical cells, photosynthesis and cellular respiration, and certain other bio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VGLUT3
Vesicular glutamate transporter 3 (VGLUT3) is a protein that in humans is encoded by the ''SLC17A8'' gene. Function This gene encodes a vesicular glutamate transporter. The encoded protein transports the neurotransmitter glutamate into synaptic vesicles before it is released into the synaptic cleft. Clinical significance Mutations in this gene are the cause of autosomal-dominant nonsyndromic deafness Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. In contrast, syndromic deafness involves hearing loss that occurs with abnormalities in other parts of the body. Genetic changes are related to the follow ... type 25 (DFNA25). References Further reading * * * * * * * * * Glutamate (neurotransmitter) Solute carrier family {{gene-12-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VGLUT2
Glutamate transporters are a family of neurotransmitter transporter proteins that move glutamate – the principal excitatory neurotransmitter – across a membrane. The family of glutamate transporters is composed of two primary subclasses: the excitatory amino acid transporter (EAAT) family and vesicular glutamate transporter (VGLUT) family. In the brain, EAATs remove glutamate from the synaptic cleft and extrasynaptic sites via glutamate reuptake into glial cells and neurons, while VGLUTs move glutamate from the cell cytoplasm into synaptic vesicles. Glutamate transporters also transport aspartate and are present in virtually all peripheral tissues, including the heart, liver, testes, and bone. They exhibit stereoselectivity for L-glutamate but transport both L-aspartate and D-aspartate. The EAATs are membrane-bound secondary transporters that superficially resemble ion channels. These transporters play the important role of regulating concentrations of glutamate in the extracel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vesicular Glutamate Transporter 1
Vesicular glutamate transporter 1 (VGLUT1) is a protein that in humans is encoded by the ''SLC17A7'' gene. The protein encoded by this gene is a vesicle-bound, sodium-dependent phosphate transporter that is specifically expressed in the neuron-rich regions of the brain. It is preferentially associated with the membranes of synaptic vesicles and functions in glutamate transport. The protein shares 82% identity with the differentiation-associated Na-dependent inorganic phosphate cotransporter and they appear to form a distinct class within the Na+/Pi cotransporter Cotransporters are a subcategory of membrane transport proteins (transporters) that couple the favorable movement of one molecule with its concentration gradient and unfavorable movement of another molecule against its concentration gradient. They e ... family. See also * Solute carrier family References Further reading * * * * * * * * Solute carrier family Neurotransmitter transporters Glutamate (neurotrans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EAAT5
Excitatory amino-acid transporter 5 (EAAT5) is a protein that in humans is encoded by the ''SLC1A7'' gene. EAAT5 is expressed predominantly in the retina, has high affinity for the excitatory amino acid L-glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn .... When stimulated by this amino acid, EAAT5 conducts chloride ions. References Further reading * * * * * Solute carrier family Glutamate (neurotransmitter) {{gene-1-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EAAT4
Excitatory amino-acid transporter 4 (EAAT4) is a protein that in humans is encoded by the ''SLC1A6'' gene. EAAT4 is expressed predominantly in the cerebellum, has high affinity for the excitatory amino acids L- aspartate and L-glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn .... When stimulated by these amino acids, EAAT4 conducts chloride ions. References Further reading * * * * * * * * * * Solute carrier family Glutamate (neurotransmitter) {{gene-19-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axon Terminal
Axon terminals (also called synaptic boutons, terminal boutons, or end-feet) are distal terminations of the telodendria (branches) of an axon. An axon, also called a nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses called action potentials away from the neuron's cell body, or soma, in order to transmit those impulses to other neurons, muscle cells or glands. Neurons are interconnected in complex arrangements, and use electrochemical signals and neurotransmitter chemicals to transmit impulses from one neuron to the next; axon terminals are separated from neighboring neurons by a small gap called a synapse, across which impulses are sent. The axon terminal, and the neuron from which it comes, is sometimes referred to as the "presynaptic" neuron. Nerve impulse release Neurotransmitters are packaged into synaptic vesicles that cluster beneath the axon terminal membrane on the presynaptic side of a synapse. The axonal terminals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dendrites
Dendrites (from Greek δένδρον ''déndron'', "tree"), also dendrons, are branched protoplasmic extensions of a nerve cell that propagate the electrochemical stimulation received from other neural cells to the cell body, or soma, of the neuron from which the dendrites project. Electrical stimulation is transmitted onto dendrites by upstream neurons (usually via their axons) via synapses which are located at various points throughout the dendritic tree. Dendrites play a critical role in integrating these synaptic inputs and in determining the extent to which action potentials are produced by the neuron. Dendritic arborization, also known as dendritic branching, is a multi-step biological process by which neurons form new dendritic trees and branches to create new synapses. The morphology of dendrites such as branch density and grouping patterns are highly correlated to the function of the neuron. Malformation of dendrites is also tightly correlated to impaired nervous syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EAAT3
Excitatory amino acid transporter 3 (EAAT3), is a protein that in humans is encoded by the ''SLC1A1'' gene. Tissue distribution EAAT3 is expressed on the plasma membrane of neurons, specifically on the dendrites and axon terminals. Function Excitatory amino acid transporter 3 is a member of the high-affinity glutamate transporters which plays an essential role in transporting glutamate across plasma membranes in neurons. In the brain, excitatory amino acid transporters are crucial in terminating the postsynaptic action of the neurotransmitter glutamate, and in maintaining extracellular glutamate concentrations below neurotoxic levels. EAAT3 also transports aspartate, and mutations in this gene are thought to cause dicarboxylic aminoaciduria, also known as glutamate-aspartate transport defect. EAAT3 is also the major route of neuronal cysteine uptake. Cysteine is a component of the major antioxidant glutathione, and mice lacking EAAT3 exhibit reduced levels of glutathione ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EAAT2
Excitatory amino acid transporter 2 (EAAT2) also known as solute carrier family 1 member 2 (SLC1A2) and glutamate transporter 1 (GLT-1) is a protein that in humans is encoded by the ''SLC1A2'' gene. Alternatively spliced transcript variants of this gene have been described, but their full-length nature is not known. Function SLC1A2 / EAAT2 is a member of a family of the solute carrier family of proteins. The membrane-bound protein is the principal transporter that clears the excitatory neurotransmitter glutamate from the extracellular space at synapses in the central nervous system. Glutamate clearance is necessary for proper synaptic activation and to prevent neuronal damage from excessive activation of glutamate receptors. EAAT2 is responsible for over 90% of glutamate reuptake within the brain. Clinical significance Mutations in and decreased expression of this protein are associated with amyotrophic lateral sclerosis (ALS). The drug riluzole approved for the treatment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Excitotoxicity")
