Molecular Mechanisms of Plasticity (L9-11)

Question 1

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AMPA Glutamate receptors.

Answer 1

• AMPA receptors are tetramers.
• Each subunit can bind one molecule of glutamate. Glutamate binds between the S1 & S2 extracellular domains.
• AMPA receptors desensitise.
• The rate of desensitisation is determined by the subunit composition and the flip/flop variant.
• Pathways requiring rapid synaptic responses have AMPARs with rapid deactivation/desensitisation kinetics.
• GluA2 subunits are post-transcriptionally edited at the Q/R site.
• AMPARs lacking the GluA2 subunit are Ca2+ permeable.
• Auxiliary subunits modulate AMPAR trafficking and gating.

Question 2

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AMPA Trafficking.

Answer 2

• Assembly of AMPARs in neurons is NOT random, but regulated in some fashion.
• AMPARs made up of different combinations of subunits can be targeted to different populations of synapses.