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Exam 4
Unit 2
50
Other
Undergraduate 4
12/11/2016

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Term
difference between central synapse & NMJ: reliability
Definition
NMJ = a really reliable synapse (when you get one action potential you're almost always going to get a contraction in that fiber...close to 100% of the time)

central = a single excitatory input will cause an AP about 0% of the time
Term
difference between central synapse & NMJ: junctional folds
Definition
central = do not have junctional folds (less dense)

NMJ = have folds with a ton of ACh receptors (why it's so reliable!)
Term
difference between central synapse & NMJ: neurotransmitters
Definition
NMJ = ACh is primary (only)

central = many different neurotransmitters (ex. glutamate)
Term
difference between central synapse & NMJ: language regarding currents/potentials
Definition
NMJ = end plate potentials/currents (EPP, EPC)

central = postsynaptic potentials, currents (EPSP, IPSP, EPSC, IPSC)
Term
difference between central synapse & NMJ: connection
Definition
NMJ = neuron to muscle

central = neuron to neuron
Term
most common excitatory neurotransmitter in the brain
Definition
glutamate
Term
VGLUT
Definition
loads glutamate into a transmitter
Term
EAATs
Definition
do glutamate re-uptake into astrocytes or presynaptic terminal
Term
glutamate is made in the cell from ______
Definition
glutamine
Term
Where do the names for ionotropic glutamate receptors come from?
Definition
the other ligands that activate them
Term
Are there metabotropic glutamate receptors?
Definition
yes!
Term
shared structure between the different types of glutamate receptors
Definition
4 subunits that make up the staves; each subunit has 3 domains (amino-terminal, ligand-binding, & TMR); M1 - M4 make up the TMR domain of each subunit
Term
glutamate receptors: ligand binding --> ? --> channel open
Definition
conformational change
Term
what does a glutamate receptor kind of look like?
Definition
a dimer of dimers
Term
3 types of ionotropic glutamate receptors (ligand-gated ion channels)
Definition
1. NMDA
2. AMPA
3. kainate
Term
What is another name for metabotropic glutamate receptors?
Definition
g-protein coupled receptors
Term
desensitization
Definition
loss of receptor responses during continued presence of a ligand
Term
Glutamate receptors quickly open, but despite continued glutamate presence, the macroscopic current bumps back to resting state indicating ______ of individual channels
Definition
desensitization
Term
Desensitization controls ______ in the presence of glutamate
Definition
the amount of time receptors are open
Term
Are desensitization & deactivation the same thing?
Definition
no!
Term
AMPA receptors are composed of _______ subunits (some combination of these)
Definition
GluA1 - GluA4
Term
Do AMPA receptors have fast or slow activation, deactivation, & desensitization?
Definition
fast
Term
AMPA receptors mediate the majority of _____
Definition
fast excitatory neurotransmission
Term
Most ______ are about equally permeable to potassium & sodium with reversal potential at about 0 mV
Definition
AMPARs
Term
Why do AMPARs have a linear IV plot (for calcium impermeable AMPA receptors)?
Definition
they aren't voltage dependent with a reversal potential around 0
Term
kainate receptors are similar to ______ electrophysiologically
Definition
AMPA
Term
What is the primary function of kainate receptors?
Definition
modulatory
Term
Kainate receptors are grouped with AMPA receptors in the _____ family of ionotropic glutamate receptors
Definition
non NMDA receptor
Term
NMDA receptors must must contain the _____ subunit
Definition
GluN1
Term
The _____ subunit of NMDA receptors bind glutamate
Definition
GluN2
Term
The ______ & ______ subunits of NMDA receptors bind co-agonists
Definition
GluN1 & GluN3
Term
How do the different GluN2 subunit types (NMDA receptors) mainly differ?
Definition
in their decay properties (desensitization)
Term
2 parts of the coincidence detection of NMDA receptors
Definition
1. depolarization
2. glutamate present
Term
At normal resting potentials (hyperpolarized), _______ can enter the NMDA receptor pore when they are open but cannot pass through --> forms a block
Definition
magnesium
Term
What region of the NMDA receptor lines the pore?
Definition
M2
Term
Asparagine (N) in the M2 region of the NMDA receptor allows _____ to pass through but not _____
Definition
allows conductance of calcium but not magnesium
Term
Why is the Q/N/R site on the M2 region of the NMDA receptor named as such?
Definition
those are the amino acids that can be present on the M2 region
Term
What does an NMDA receptor IV plot look like for the ones with magnesium block?
Definition
there is a dip at hyperpolarized current (not just a flat line)
Term
What does the IV plot for NMDA receptors without a magnesium block look like?
Definition
basically linear
Term
How do NMDA receptors with a magnesium block compare with NMDA receptors without a magnesium block in terms of their IV plots?
Definition
line up pretty much exactly at depolarized voltages
Term
NMDAR conduct only when the cell is already _____
Definition
depolarized
Term
NMDAR require a "coincidence" of what two things?
Definition
post synaptic depolarization & glutamate
Term
3 things NMDAR are important for
Definition
1. learning
2. memory
3. development
Term
long term potentiation
Definition
increase in synaptic strength after high frequency stimulation
Term
______ influx through NMDAR activates signaling cascades that increases the number of receptors in the synapse
Definition
calcium
Term
Is LTP only caused by NMDA stuff?
Definition
no!
Term
What is the saying associated with NMDARs & development?
Definition
"fire together, wire together"
Term
As synapses start to form, NMDA receptors can start to _____
Definition
stabilize
Term
NMDARs' role in development may be similar to _____
Definition
LTP
Term
excitotoxicity
Definition
cell death usually caused by too much calcium that can happen due to over activation of NMDARs
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