Term
| What is the main excitatory amino acid neurotransmitter? |
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Definition
Glutamate
- estimated that over half of brain synapses release glutamate |
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Term
| Which amino acids act as neurotransmitters |
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Definition
Excitatory:
Glutamate
Aspartate
Inhibitory:
GABA (g-amino butyric acid)
Glycine |
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Term
| What is the difference between Glutamate and Aspartate? |
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Definition
| Aspartate has one less methyl group |
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Term
| Glutamate and aspartate are non-essential amino acids. What does that mean? |
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Definition
| non-essential = Synthesised in the body – not required in the diet |
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Term
| WHat is the relative abundance of Glutamate in the brain? |
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Definition
|
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Term
| What is the relative abundance of Aspartate in the Brain? |
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Definition
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Term
| What is the first pathway synthesis of Glutamate? |
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Definition
Glycolysis – oxidative metabolism of glucose
Glucose --> pyruvate --> Acetyl CoA --> Krebs cycle --> α-ketoglutarate -->glutamate |
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Term
| What is the second pathway synthesis of Glutamate? |
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Definition
|
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Term
Which enzyme catalyses this reaction :
glutamine --> glutamate ? |
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Definition
|
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Term
| Which pathway is prefered for release of glutamate? |
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Definition
| Pathway 2 using enzyme Glutaminase |
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Term
| How does glutaminase prevent glutamate overproduction? |
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Definition
| This enzyme is subject to product inhibition |
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Term
| Can glutamate cross the BBB? |
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Definition
| No, therefore it is synthesized using local precursors in the neurons |
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Term
| The glutamine cycle in neurons |
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Definition
Glutamine --> glutamate
using enzyme = Glutaminase |
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Term
| The glutamine cycle in astrocytes |
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Definition
Glutamate ---> Glutamine
using enzyme = Glutamine synthase |
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Term
| Reversal of transaminase reaction |
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Definition
| glutamate --> α-ketoglutarate |
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Term
|
Definition
| glutamate --> α-ketoglutarate |
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Term
| How is glutamine taken up into presynaptic terminal ? |
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Definition
| Through System A transporter 2 (SAT2) |
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Term
| Where is Glutamate synthesized? |
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Definition
|
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Term
| Where is glutamate stored? |
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Definition
| In vesicles at the terminal |
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Term
| How is glutamate packaged into vesicles? |
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Definition
| Through Vesicular Glutamate transporter (VGLUT) and use the proton antiporter system |
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Term
| VGLUT are highly specific for ... but have low affinity of .... |
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Definition
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Term
| There are 3 genes identified with three different types of VGLUT. What are the 3 types? |
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Definition
| neuronal, cerebellar, astrocytic |
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Term
| Which disorder shows abnormality in Glutamate transporter ? |
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Definition
| amyotrophic lateral sclerosis (ALS) |
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Term
| How many transmembrane proteins are there in Glutamate transporters? |
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Definition
| 6 - 10 transmembrane proteins |
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Term
| Which transporter removes Glutamate from the synaptic cleft? |
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Definition
| Excitatory Amino Acid transporter (EAAT) family of 5 Na dependent glutamate co-transporters |
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Term
| Distribution of subtypes of EAAT |
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Definition
EAAT1 (GLAST) – neurons and astroglia, particularly Bergmann glia, cortex, hippocampus and cerebellum
EAAT2 (GLT1) – astroglia
EAAT3 (EAAC1) – neurons
EAAT4 – cerebellar Purkinje cells in rat and human CNS
EAAT5 – primarily expressed in the retina – only cloned from human |
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Term
| What are the metabotropic receptors for Glutamate? |
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Definition
mGluR1 – mGluR8
They have Slow, modulatory effects |
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Term
| What are the ionotropic receptors for Glutamate? |
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Definition
AMPA, kainate, NMDA
Fast synaptic transmission |
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