Lecture 4 Flashcards
where does calcium enter during synaptic transmission
calcium enters the pre synaptic terminal
list the 4 stpes of synaptic transmission
- calcium enters the presynaptic terminal
- neurotranmitters are released
- the vesicles containing the neurotransmitters are endocystoed and recycled
- receptors on the postsynpatic membrane open channels and cause signaling postsynaptically
what ion do neurotransmitters need in order to be released
calcium
when there is an influx in calcium what happens to membrane potential
there is a change in membrane potential post synaptically
how can we indirectly measure the amount of neurotransmitter release
meausing the resulting change in voltage in the post synaptic cel
if there is a change in voltage in a post synaptic neuron what is it called
post synaptic membrane potential
if the post synaptic cell is a muscle cell and there is a change in membrane potential what is it called
end plate potential
define PSP
psp synaptic membrane potential , if there is a change in voltage and the post synaptic cell is a neuron
define epp
if the post synaptic cell is a muscle cell and there is a change in voltage
t/f lowering the amount of extracellular calcium changes the amount of neurotransmitter release
true
what is essential to neurotransmitter release
calcium
when we inject calcium do we get an increase or decrease in epp
increase
what is a keylator
it binds to calcium to inactivate it
what is a neurotransmitter
it is a substance that has an effect on a post synaptic cell
are neurotransmitters found in pre or post synaptic cell
presynaptic cell
are neurotransmitters released in response to presynaptic depolarization or hyperpolarization
depolarization
how do neurotransmitters affect the post synaptic cell
by binding to specific receptors
how many types of neurotransmitters are there
2
name the 2 types of neurotransmitters
- small molecule neurotransmitters
2. neuropeptide transmitters
how are small molecule neurotransmitters packaged
in small clear core vesicles
where are small molecule neurotransmitters synthesized
in the terminal
what is the reuptake mechanism for small molecule neurotransmitters
recycled in the terminal
how are neuropeptide transmitters packaged
in large dense core vesicles
where are neuropeptides synthesized
in the soma
what is the reuptake mechansim for neuropeptide transmitters
they degrade after they are released
clear core vesicles that are close to the pre synaptic terminal are also known as
readly releasable pool
what is the reserve pool
clear core vesicles that are not close ot he the presynaptic membrane
what is a co transmitter
a neuron that can release more than one kind of neurotransmitter.
what kind of neurotransmitters do co transmitters typically release
small molecule transmitter and neuropeptide transmitter
where are calcium channels positioned
close to the presynaptic membrane
where is concentration of calcium the highest
clsoe to the pre synaptic membrane
where are clear core vesicles only released from
the readly releasable pool
what does an influx of calcium trigger
the release of neurotransmitters
t/f the principles of synaptic transmission apply whether the post synaptic cells is a muscle or a neuron
true
sometimes you see small epps or psp’s with out stimultion these mini events are called
mepps or mpsps
neurotransmitters come in ________s
packets
each packet produces _ _____ sized response
1, MEPP
how many packets make up an epp
several
what is 4-AP
Voltage gaed potassium channel blocker
where does synapsin bind
it reversibly binds to synaptic vesicles
what is synapsin a good marker of
pre synaptic terminals
which pool is synapsin released from
the reserve pool
which pool os CamKII released from
the reserve pool
what does CamKII stand for
ca/ calmodulin-dependent protein kinase type 2
what is CamKII sensitive to
calcium levels
what kind of proteins do fusion use
SNARES
where is synaptobrevin found
membrane of the vesicle
where is syntaxin , snap 25 found
the plasma membrane
what is SNARE involved in
it is involved in the fusion of vesicles to the pre synaptic membrane
these 2 proteins help vesicles get close to the plasma membrane
syntaxin and snap 25
name the protein that binds to calcium so that it can interact with SNARE and allows vesicles to fuse
synaptotagmin
what occurs to the vesicles carrying neurotransmitters after they are released
they are endocytosed and recycled
if vesicles fuse to the plasma membrane , what prevents terminals from just getting bigger
synaptic vesicle recycling
clathrin plays a role in what function
endocytosis
where does clathrin attach and what does it coat
clatherin attaches to the vesicular membrane and coats the budding vesicle
the molecular shape of the clathrin physically forces the membrane it binds to into what shape?
into a ball shape
what is the role of receptors on the postsynaptic membranes
they open channels and cause signal post synaptically
how does neurotransmitter binding to receptors affect the post synaptic cell
neurotransmitter binding generates a response in the post synaptic cell
what is end plate current
a response in the post synaptic cell due to a neurotransmitter binding
what is post synaptic current
if the postsynaptic cell were another neuron
what neurotransmitter does the NMJ use
acetylcholine
what isthe post synaptic receptor in the NMJ
acetylichiline receptor
what is reversal potential
when there is no net movement of ions
can sodium and k calcium go thorugh acetylcholine receptors
yes
at the time a muslce is stimulated by acetylcholine is the muscle usually at rest
yes
what is the resting membrane potential of a muscle
-90mv
acetylcholine receptors are permiable to what 2 ions
sodium and potassium
when a cell is at rest , most of the current is due to what ion. (this ion will also depolarize the cell )
sodium
are epsp’s excitatory or inhibitory
excitatory
PSP’s that increase the likelihood of firing are ____ because they cause _____
excitatory, depolarization
psp’s are _____ if they decrease the likelihood of firing, the cell becomes (depolarized/hyperpolarized)
inhibitory, hyperpolarized
epsp’s result from activating receptors that open channels with a reversal potential that is ______ threshold
over
ipsp’s result from activating receptors that open channels with a reversal potential that is ______ threshold
below
define summation
most neurons recieve many inputs from both excitatory and inhibitory synapses. Neurons sum the PSP’s to determine their overall membrane potential
define inhibitory input
it will hyperpolarize the membrane potential ( make it more negative )
list the 7 steps of synaptic transmission in order
- neurotransmitter release
- receptor binding
- ion channels open or close
- conductance change causes current flow
- postsynaptic potential changes
- post cells excited or inhibited
- summation determines whether or not an action potential occurs
