Glutamate Flashcards
What type of neurotransmitter is glutamate?
Main excitatory CNS neurotransmitter
How is glutamate produced?
TCA cycle from alpha-ketoglutarate
Where do we obtain our dietary supply of glutamate?
Proteins Monosodium glutamate (MSG)
What type of receptors are activated by glutamate?
Ionotropic
What are the 3 ionotropic receptors activated by glutamate?
1) AMPA
2) Kainate
3) NMDA
What are the channel properties of the AMPA receptors?
Permeable mainly to Na+ and K+
Apart from glutamate, name 2 other agonists for the AMPA receptors
Kainate and domoate
What is the action of 2,3-benzodiazepines on AMPA receptors?
Competitive antagonists
Difference between inhibition of AMPA and Kainate receptors?
Kainate receptors not inhibited by 2,3-benzodiazepines
Do AMPA or Kainate receptors have higher Ca2+ permeability?
Kainate
What can be said about the location of Kainate receptors in the brain?
Located in few brain areas only
What does NMDA stand for?
N-Methyl-D-Aspartate
How are NMDA receptors different to AMPA and Kainate receptors?
More permeable to Ca2+ ions
What are the subunits NMDA receptors?
GluN1 or GluN2
Which subunits does glutamate bind on NMDA receptors?
GluN2 subunits
For glutamate binding NMDA receptors, what binds to the GluN1 subunit for receptor activation?
Co-agonist
- > glycine
- > D-serine
What is attracted into the pore of the NMDA receptor at -ve membrane potentials?
Magnesium
What is the action of Mg when attracted into the pore of the receptor?
Blocks receptor
How is Mg expelled from NMDA receptors to relieve block?
Membrane depolarisation
What is the result of substantial glutamate release on NMDA receptors?
Sustains postsynaptic depolarisation, relieves Mg block, activating receptor and allowing Ca influx
