Lecture 4: Chemical Synaptic Transmission: Recycling and Reuptake Flashcards
Heuser & Reese (1973) experiment significance
showed recycling occurs by using horseradish peroxidase to label vesicles
Yamashita et al (2005, 2010) experiment significance
after stimulation of a presynaptic neuron, capacitance of the presynaptic membrane does up
synaptophysins function
marks changes in acidity (fluorescent pH marker)
- light up when acidity goes down & NT is released from vesicle
Royle (2012) and Granseth (2006) experiments significance
used synaptophysins to measure vesicle fusion; stuck it to the vesicle by attaching it to a vesicular SNARE
SNAP & NSF function in clathrin-mediated endocytosis
keep vesicular proteins together as they move to the perisynaptic region to be endocytosed
adaptor proteins in endocytosis
AP-2, Stonin, AP-180
adaptor proteins function in clathrin-mediated endocytosis
help coordinate & recruit clathrin monomers
clathrin monomer function in clathrin-mediated endocytosis
form a cage, invaginating the membrane
dynamin rings function in clathrin-mediated endocytosis
‘cut’ the vesicle in a GTP-dependent manner
Auxilin, Hsc70, synaptojanin function in clathrin-mediated endocytosis
support removal of clathrin & ready the synaptic vesicle for endosomal entry
first step for clathrin-mediated endocytosis of exhausted synaptic vesicles
adaptor proteins connect clathrin to vesicular membrane
second step for clathrin-mediated endocytosis of exhausted synaptic vesicles
clathrin triskelia assemble into a coat, curving membrane to form coated pit
third step for clathrin-mediated endocytosis of exhausted synaptic vesicles
assembled clathrin cage constricts lipid stalk connecting two membranes
fourth step for clathrin-mediated endocytosis of exhausted synaptic vesicles
dynamin ring forms and pinches off lipid stalk
fifth step for clathrin-mediated endocytosis of exhausted synaptic vesicles
coated vesicle is translocated by actin filaments
sixth step for clathrin-mediated endocytosis of exhausted synaptic vesicles
Hsc70 & auxilin uncoat vesicle
acetylcholinesterase reaction
acetylcholine –> acetate + choline
where does acetylcholinesterase work
in synaptic cleft
how is choline brought back into presynaptic membrane
via transporters, often Na+ co-transporters
acetylcholine vesicular transporter
vAChT
how is glutamine brought back into the presynaptic membrane for glutamate
via transporters
- SN1 –> SAT2
glutamine synthesis
glutamate –> glutamine + phosphate
where does glutamine synthesis usually occur
astrocytes
glutaminase reaction
glutamine + phosphate –> glutamate
where does glutaminase reaction occur
in presynaptic terminal
glutamate vesicular transporter
VGLUT
how is glutamine brought back into presynaptic membrane for GABA
via GAT (Na+ co-transporter)
how is GABA broken down
via multiple pathways via mitochondrial enzymes
GABA synthesis
glucose –> glutamate –> GABA
glutamic acid decarboxylase (GAD) function
completes the final step of GABA synthesis
GABA vesicular transporter
VIAAT
