NMDA Receptors Flashcards
What are the properties of NMDA receptors?
- Permeable to Ca2+
- Blocked by Mg2+ at resting potential
- Activation is ligand-gated and voltage-dependent
- Maximal activation requires extracellular glycine
What are NMDA receptors?
Ionotropic glutamate receptors
When was long-term potentiation discovered, and who was it discovered by?
Bliss & Lomo (1973)
What did Bliss & Lomo (1973) discover?
Long-term potentiation
What are the features of long-term potentiation?
- Pathway specific
- Displays associativity
- Pairs pre-and post synaptic cells
What are the molecular mechanisms of long-term potentiation?
- 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
What effect does blocking NMDA receptors have on long-term potentiation?
Long-term potentiation will not occur
By what process does the post synaptic entry of CA2+ trigger long-term potentiation?
- CA 2+ activates calmodulin
- Calcium/calmodulin (CaM) activates CaM-kinase II
- Phosphorylation of AMPA receptors causes increased responsiveness to glutamate
What does the induction of long-term potentiation require?
Postsynaptic NMDA receptors
What does the expression of long-term potentiation require?
An increase in the activity/number of postsynaptic AMPA receptors
How does long-term potentiation at the mossy fibre differ from long-term potentiation elsewhere?
- NMDA receptor independence
* Presynaptic expression
what is long-term depression?
A decrease in postsynaptic responsiveness due to reduced activity
How are long-term potentiation and depression induced?
- LTP = high-frequency stimulation
* LTD = low-frequency stimulation
How does long-term depression reduce postsynaptic activity?
Down-regulation of AMPA receptors due to Ca2+ entry via postsynaptic NMDA receptors
