Neuronal signalling 7 (3rd lecture) Flashcards
Which brain area is associated with spatial memory?
Hippocampus
Which brain area is involved with fear memory?
Amygdala
Granul cell layer components?
Mossy fibre axon,
Where does the mossy fibre axon project from and to?
Granual cell layer of the hippocampus to the pyrimidal cell of the CA3 region
Name of axons leaving CA3 region?
Schafer collaterals
Where do Schafer Collaterals innervate?
Pyramidal cells in the CA1 region
What is the mossy fibre axon and CA3 regions of the hippocampus used to study?
Memory/LTP
What are the three principal hippocampal pathways?
perforant, mossy fibre and schaffer collateral
Perforant pathway?
entorhinal cortex to dentate gyrus
Granule cells
Mossy fibre pathway?
dentate gyrus to the CA3
Pyramidal cells
Schaffer collateral pathway?
CA3 to CA1
Pyramidal cells
Which pathways use pyramidal cells?
Mossy fibre and schaffer collateral
Difference in EPSP following potentiation?
Larger EPSP following potentiation in response to the same level of stimulus
What happens to the amplitude of the potentiated synapse?
Higher probability of a larger amplitude, a larger current
Two groups of LTP mechanism?
Pre and postsynaptic
Presynaptic LTP mechanism?
Increase in probability of NT release
Postsynaptic mechanism of LTP?
More AMPA receptors w/ a diff function
Change in CaMKII for LTP?
More active CaMKII = more NT release
Change in expression of other kinases
Effect of phosphorylation on AMPA receptors?
Increased conductance, and increased activity
Largest receptor effect on LTP?
NMDA receptors are now included
What is a silent synapse?
A non-potentiated synapse that thus doesn’t have active NMDA receptors
How do NMDA receptors facilitate LTP?
More of them, allows Ca in which can add more AMPA receptors via altered protein synthesis
What is inside the NMDA receptor at rest?
Mg2+ ion
What is NMDA overactivity associated with?
Cell death mechanisms
Why is NMDA overactivity associated with cell death mechanisms?
It allows Ca2+ entry into cells which can trigger cell death, and destabilisation of mitochondria
What needs to bind alongside glutamate to activate an NMDA receptor?
Glycine
Where does glycine bind?
Allosteric site
Why is “gate opening” not sufficient for ions to pass through an NMDA receptor?
Mg2+ block
What is Mg2+ NMDA block removal dependent on?
Membrane depolarisation
How can NMDA receptors be regulated?
Polyamines, phosphorylation, activation of protein kinase C, redox
Why are there so many ways to regulate NMDA pathways?
Memory is complex and v different so lots of variability is needed
How many subunits does an NMDA receptor have?
4
2 primary NMDA subunits?
NR1 and NR2
Which NMDA subunit does glutamate bind to?
NR2
Which NMDA subunit does glycine bind to?
NR1
How many splice variants does NR1 have?
8
How many splice variants does NR2 have?
4
When are the diff NR1 and 2 splice variants used?
Diff brain areas, diff times in development
Where does the Mg2+ bind to on an NMDA receptor?
NR2
What are retrograde messengers?
Messengers sent byt he postsynaptic cell to modulate the NT release from the pre n
Retrograde messenger examples?
Nitric oxide, carbon monoxide, arachidonic acid
How is arachidonic acid obtained?
Product of lipid metabolism
What can NT vesicles contain?
NT and neuropeptide
