What is EAAT in neuroscience?
Excitatory amino acid transporters, or EAATs, serve as the major mechanism for limiting the action of the excitatory amino acid glutamate in the central nervous system.
What do excitatory amino acid transporters do?
Excitatory amino acid transporters (EAATs) are secondary active, electrogenic transport systems that couple the accumulation of glu into the cytoplasm to downhill movement of co-transported ions along their concentration gradient.
What does glutamate do?
Glutamate is an important neurotransmitter present in over 90% of all brain synapses and is a naturally occurring molecule that nerve cells use to send signals to other cells in the central nervous system. Glutamate plays an essential role in normal brain functioning and its levels must be tightly regulated.
How do glutamate transporters work?
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. The activity of glutamate transporters also allows glutamate to be recycled for repeated release.
Where is EAAT2 expressed?
EAAT2 is expressed predominantly in astrocytes but is also present in neurons and excitatory axon terminals (16). Neuronal EAAT2 only constitutes 5 to 10% of all EAAT2 protein in the brain (16).
Where is glutamine synthetase found?
GS is present predominantly in the brain, kidneys, and liver. GS in the brain participates in the metabolic regulation of glutamate, the detoxification of brain ammonia, the assimilation of ammonia, recyclization of neurotransmitters, and termination of neurotransmitter signals.
Why is EAAT function so important for glutamate function?
The EAATs are membrane-bound pumps that closely resemble ion channels. These transporters play the important role of regulating concentrations of glutamate in the extracellular space, maintaining it at low physiological levels that promote biological function without promoting toxicity.
What is the biological purpose of Excitotoxicity?
Excitotoxicity refers to the energy metabolism disorder caused by cerebral ischemia and hypoxia that directly inhibits the activity of sodium and potassium ion channels of the cytoplasmic membrane, increases the concentration of extracellular potassium, releases excitatory amino acids in the synaptic cleft of neurons.
Are glutamates bad for you?
Why You Should Avoid Glutamate The relatively high glutamate levels in some traditional diets suggest that it is a safe food additive. However, anecdotal and scientific evidence indicates that high levels of glutamate and MSG consumption cause adverse health effects.
Where are glutamate transporters located?
Na+-dependent glutamate transporters (EAATs) located on the plasma membrane of neurons and glial cells rapidly terminate the action of glutamate and maintain its extracellular concentration below excitotoxic levels.
What is the role of glutamine synthetase?
The enzyme glutamine synthetase is a key enzyme controlling the use of nitrogen inside cells. Glutamine, as well as being used to build proteins, delivers nitrogen atoms to enzymes that build nitrogen-rich molecules, such as DNA bases and amino acids.
How are glutamate transporters involved in excitotoxicity?
Without the activity of glutamate transporters, glutamate would build up and kill cells in a process called excitotoxicity, in which excessive amounts of glutamate acts as a toxin to neurons by triggering a number of biochemical cascades. The activity of glutamate transporters also allows glutamate to be recycled for repeated release.
Where are glutamate transporters located in the brain?
Glutamate transporters, also known as excitatory amino acid transporters (EAATs), are sodium- and potassium-dependent members of the solute carrier family 6 (SLC1) found widely distributed throughout the brain.
Where is EAAT2 found in the central nervous system?
However, low levels of EAAT2 are also found in the axon-terminals of hippocampal CA3 pyramidal cells. EAAT2 is responsible for over 90% of glutamate reuptake within the central nervous system (CNS). The EAAT3-4 subtypes are exclusively neuronal, and are expressed in axon terminals, cell bodies, and dendrites.
Where does glutamate go after it is converted to glutamine?
When glutamate is taken up into glial cells by the EAATs, it is converted to glutamine and subsequently transported back into the presynaptic neuron, converted back into glutamate, and taken up into synaptic vesicles by action of the VGLUTs. This process is named the glutamate–glutamine cycle .