NMDA Receptors

Question 0

What are the properties of NMDA receptors?

Answer 0

• Permeable to Ca2+
• Blocked by Mg2+ at resting potential
• Activation is ligand-gated and voltage-dependent
• Maximal activation requires extracellular glycine

Question 1

What are NMDA receptors?

Answer 1

Ionotropic glutamate receptors

Question 2

When was long-term potentiation discovered, and who was it discovered by?

Answer 2

Bliss & Lomo (1973)

Question 3

What did Bliss & Lomo (1973) discover?

Answer 3

Long-term potentiation

Question 4

What are the features of long-term potentiation?

Answer 4

• Pathway specific
• Displays associativity
• Pairs pre-and post synaptic cells

Question 5

What are the molecular mechanisms of long-term potentiation?

Answer 5

• EPSPs mediated by AMPA receptors
• Single pulse triggers EPSP in CA1 cells
• Pyramidal cells also express multi-pulse NMDA receptors
• Tetanic stimulus triggers AMPA and NMDA receptors
• Elevation of postsynaptic calcium is the trigger for long-term potentiation

Question 6

What effect does blocking NMDA receptors have on long-term potentiation?

Answer 6

Long-term potentiation will not occur

Question 7

By what process does the post synaptic entry of CA2+ trigger long-term potentiation?

Answer 7

• CA 2+ activates calmodulin
• Calcium/calmodulin (CaM) activates CaM-kinase II
• Phosphorylation of AMPA receptors causes increased responsiveness to glutamate

Question 8

What does the induction of long-term potentiation require?

Answer 8

Postsynaptic NMDA receptors

Question 9

What does the expression of long-term potentiation require?

Answer 9

An increase in the activity/number of postsynaptic AMPA receptors

Question 10

How does long-term potentiation at the mossy fibre differ from long-term potentiation elsewhere?

Answer 10

• NMDA receptor independence

* Presynaptic expression

Question 11

what is long-term depression?

Answer 11

A decrease in postsynaptic responsiveness due to reduced activity

Question 12

How are long-term potentiation and depression induced?

Answer 12

• LTP = high-frequency stimulation

* LTD = low-frequency stimulation

Question 13

How does long-term depression reduce postsynaptic activity?

Answer 13

Down-regulation of AMPA receptors due to Ca2+ entry via postsynaptic NMDA receptors