Lecture 11 Synaptic Transmission Part 2 Flashcards
AP blocks ________ and prolongs AP and the amount of ________ that can enter
K+, Ca2+
When AP blocks K+ and prolongs the action potential and the amount of Ca2+ that can enter, what 2 things can happen?
leads to more quanta
Correlates perfectly with number of fused vesicles in EM.
Name 2 events in fusion of a transport vehicle.
1) transport vehicle must recognize the correct target membrane
2) the vesicle and target membrane must fuse
Why must the target membrane and vesicle fuse?
So content of vesicle can be delivered to organelle or into synaptic cleft.
Proteins involved in synaptic release have what functions?
- Restrain vesicles
- Target and dock vesicles to active zone
- Allow fusion/exocytosis
- Recycle
________ tethers vesicles to the cytoskeleton
Synapsin
_______ phosphorylates synapsin to mobilize _______ pool
CaMKII, reserve
Groups of proteins that promote fusion of the vesicle and presynaptic membrane
SNAp Receptors
Describe the 3 main players in the SNARE hypothesis?
v-SNARE (Synaptobrevin): sits in vesicle
t-SNARE (Syntaxin):presynaptic membrane
Synaptotagmin-calcium sensor
What is munc-18?
Part of SNARE, binds with syntaxin to inhibit SNARE complex formation
What interacts with synaptotagmin and leads to fusion
Neurexins
NSF and alpha-SNAP are responsible for _________. Bind SNARE, uitilizes ATP to break apart complexes after fusion
priming
Is Synaptotagmin a SNARE?
no
Synapsins are regulated by what 2 kinases?
cAMP-dependent kinase and Ca2+/Calmodulin dependent kinases
Rab proteins are small ________ binding proteins
GTP
Name some functions of rab proteins
vesicle formation, vesicle movement, fusion (interacts with vSNARES to initiate fusion)
Synaptotagmin binds _________ and __________(in a calcium dependent manner)
clathrin, phospholipids
Clathrin and dynamin are involved in ___________.
endocytosis
What does clathrin do?
forms coated pits
What does dynamin do?
pinches off coated vesicle
________ consist of 4-5 subunits that open a pore upon receptor binding.
Multimers
Direction of PSP is determined by what?
ionic identity
equilibrium/reversal potential
An EPSP has a reversal potential more ________ than AP threshold.
positive
An IPSP has a reversal potential more ________ than AP threshold
negative
Excitatory input is due to release of glutamate and is permeable to both ___ and ____.
Na+ and K+
Inhibitory input is due to release of GABA and is permeable to _____.
Cl-
A synaptic potential can be _________ and ________.
depolarizing, inhibitory
Ecl- is more ___________ than AP threshold.
hyperpolarized
Shunting inhibition is an increase in _______________.
resting conductance
Post synaptic graded responses are summed in the _______.
soma
