Glutamate and its Receptors

Question 1

List the four criteria for NT status.

Answer 1

Must be made by neurons.
Must be released by presynaptic neurons.
Must activate postsynaptic receptors.
Must be inactivated by enzymes or reuptake.

Question 2

How does glutamate meet the NT criteria?

Answer 2

Concentrated in synaptic vesicles.
Released by exocytosis.
Binds to a large family of glutamate receptors.
Reuptake across membrane by EAA1-4 family of transporters.
Has functional effects.

Question 3

How does glutamate bind to many different receptors?

Answer 3

It is a flexible molecule because different components can rotate along two different axes: alpha-beta bonds and beta-gamma bonds.

Question 4

How many different conformations/rotamers can glutamate adopt?

Answer 4

9

Question 5

How is glutamate selective between receptors?

Answer 5

Glutamate release is localised to the PSD. Receptors are anchored opposite the release sites, and have different affinities for glutamate.

Question 6

What does NMDAR require to open?

Answer 6

Glutamate binding.
Depolarisation (to relieve Mg2+ block).
Glycine as a co-agonist.

Question 7

What are the two roles of postsynaptic mGluRs?

Answer 7

Produce slow depolarisation.
Release calcium from intracellular stores.

Question 8

What are the two roles of presynaptic mGluRs?

Answer 8

Inhibit AP-evoked glutamate release.
Increase background glutamate release.

Question 9

What is the role of neuroligin?

Answer 9

Links pre- and postsynaptic cells.

Question 10

What is the PDZ?

Answer 10

Where additional AMPARs are inserted during LTP.