Concept Map 09 by Sophie Gregoretti

key

gregoretti668 — 2023-10-27 20:49:24 UTC

blue = lecture

green = reading

yellow = article

life cycle of vesicles

gregoretti668 — 2023-10-27 20:54:46 UTC

electrical vs chemical synapses

gregoretti668 — 2023-10-27 20:55:50 UTC

most are chemical

ligand-gated ion channels vs G-protein-coupled receptors (GPCRs)

gregoretti668 — 2023-10-27 20:59:14 UTC

ionotropic = ligand gated

type of metabotropic channel = GPCR

when NT is released, communicated w receptors on the post-synaptic side to effect a response

gregoretti668 — 2023-10-27 21:03:21 UTC

if receptor is ligand gated, ions flow through channel to change membrane potential of post synaptic cell

gregoretti668 — 2023-10-27 21:03:37 UTC

neurotransmitter release overview

gregoretti668 — 2023-10-27 21:04:01 UTC

quantal release

gregoretti668 — 2023-10-27 21:12:15 UTC

relationship between synaptic vesicle exocytosis and quantal transmitter release

1 quanta of NT = 1 vesicle fusing

Katz looked at the NMJ = end plates

EPP: end plate potential

change in membrane potential such that an AP of the presynpatic neurons can elicit a depolarization of the muscle fibers
summation of many quanta release

mEPPs - mini

spontaneous release
1 quanta of NT, discrete packet of

formation: vesicle types

gregoretti668 — 2023-10-27 21:21:30 UTC

synaptic vesicles (SV)

generated from any of the endosomes in the endosomal pathway
generated in the soma then trafficked to the axon terminal

secretory granules (SG) = dense core vesicles bc it's electron dense

generated form the Golgi initially as immature secretory granules then mature into secretory granules
generated in Golgi of the soma then trafficked to the axon terminal

release of NT at the active zone of a synapse

gregoretti668 — 2023-10-27 21:47:07 UTC

vesicle targeting

gregoretti668 — 2023-10-27 21:49:24 UTC

vesicles have proteins attached to them
proteins tell the vesicle where its going to help it fuse w its target membrane

VGLUT --> this is a glutamate vesicle --> carried glutamate NT

gregoretti668 — 2023-10-27 21:51:37 UTC

vesicles are made of phospholipids

must overcome hydrophilic heads repulsion, so force must be applied
SNARE complex generates the force necessary to fuse plasma and vesicle membrane to allow exocytosis

plasma membrane

gregoretti668 — 2023-10-28 13:57:41 UTC

has

SNAP-25 (a t-SNARE)
Syntaxin (a t-SNARE)

together: SNAP-25, syntaxin, and synaptobrevin make up the SNARE complex

exocytosis = vesicle release

gregoretti668 — 2023-10-28 13:58:18 UTC

gregoretti668 — 2023-10-28 13:58:46 UTC

gregoretti668 — 2023-10-28 14:02:08 UTC

vesicle recycling

gregoretti668 — 2023-10-28 14:02:42 UTC

kiss and run vs full fusion

gregoretti668 — 2023-10-28 14:07:35 UTC

kiss and run: vesicle targets, tethers, and docks like all other vesicles; during exocyotosis, vesicle membrane DOESN'T fully fuse w the plasma membrane, only opens to release contents, then reseals

full fusion: normal vesicle target, tether, and dock; vesicle fully fuses w plasma membrane

clathrin mediated endocytosis, after full fusion

gregoretti668 — 2023-10-28 14:08:22 UTC

goal: tight correspondence btwn neuronal activity and synchronous releases of NTs

gregoretti668 — 2023-10-30 16:19:37 UTC

synaptic vesicles contain NTs

gregoretti668 — 2023-10-30 16:20:37 UTC

gregoretti668 — 2023-10-30 16:22:23 UTC

synaptic vesicles are releases from the active zone: a stretch of synaptic membrane facing the postsynaptic vesicle across the divide of the synaptic cleft

gregoretti668 — 2023-10-30 16:23:23 UTC

some synaptic vesicles are docked at the active zone then primed for release by protein complexes that bring them into extreme proximity of the plasma membrane

passive diffusion

gregoretti668 — 2023-10-30 16:27:06 UTC

NTs molecules passively diffuse across the synaptic cleft to reach the post synaptic cell

gregoretti668 — 2023-10-30 16:29:23 UTC

active zone membrane is endocytosed and synaptic vesicles membrane proteins are then reassembled into recycled synaptic vesicles --> used for more NT releases

gregoretti668 — 2023-10-30 16:35:56 UTC

minimize spontaneous release

gregoretti668 — 2023-10-30 16:36:16 UTC

synchronous release to neuronal activity

NT release timing

gregoretti668 — 2023-10-30 16:38:00 UTC

SNAREpin

gregoretti668 — 2023-10-30 16:40:22 UTC

protein complex at the active zone that docks some synaptic vesicles to the active zone
synaptic vesicles are primed for triggered release by conformational changes in SNAREpin and simultaneously prevented from spontaneous release through interactions btwn complexin and SNAREpin

gregoretti668 — 2023-10-31 14:14:35 UTC

end plate is the current at the end of post synaptic side of the NMJ in an intact organism

gregoretti668 — 2023-10-31 14:22:06 UTC

vesicle is different if the NTs are small molecule or peptide NTs

all vesicles have

gregoretti668 — 2023-10-31 14:36:01 UTC

V-SNARE, VAMP, or synaptobrevin
a neurotransmitter (loads the NT vesicles)
synaptotagmin (the Ca sensor)

gregoretti668 — 2023-10-31 14:38:34 UTC

gregoretti668 — 2023-10-31 14:48:23 UTC

need recycling bc there would be too many vesicles on the synapses and there wouldn't be space for more vesicles

SNARE COMPLEX

gregoretti668 — 2023-11-01 20:45:08 UTC

SNARE complex:

vSNARE = VAMP = synaptobrevin (in red in the picture)

SNAREpin (in blue in the picture)

SNAP-25
synatxin

synaptotagnin: senses change in [Ca], allows release of complexin

complexin: allows SNARE complex to change from trans to cis conformation --> exocytosis

when there isn't an action potential occurring, vesicles are being held at the presynaptic membrane in the SNARE protein. complexin inhibits conformation of SNARE complex that would allow exocytosis. when syntaxin detects change in [Ca] during action potential, it allows complexin to release, so the SNARE complex zip together (picture), allowing exocytosis of NTs in the vesicle

gregoretti668 — 2023-11-03 01:42:26 UTC

psilocybin might be effective for mood disorder and substance use disorders

gregoretti668 — 2023-11-03 01:44:01 UTC

reduced amygdala response to negative affect stimuli

gregoretti668 — 2023-11-03 01:44:17 UTC

12 healthy volunteers

gregoretti668 — 2023-11-03 01:44:55 UTC

!!! in all brain regions, BOLD change returned to baseline after 1 month, only negative after 1 week

gregoretti668 — 2023-11-03 01:45:34 UTC

gregoretti668 — 2023-11-03 01:46:41 UTC

increased number of significant resting-state functional connection from baseline --> 1 week --> 1 month

gregoretti668 — 2023-11-03 01:47:25 UTC

mostly created prefrontal and temporal functional connections during all durations of treatment

gregoretti668 — 2023-11-03 01:50:50 UTC

gregoretti668 — 2023-11-03 01:52:46 UTC

psilocybin might not be as effective after 1 month bc of psilocybin's half life, but change observed after 1 week might be bc psilocybin improves top-down processing to pt's can have more brain region regulation in response to emotional stimuli

reported in other lit: increase in amygdala activity 1 day after treatment

gregoretti668 — 2023-11-03 01:56:31 UTC

increase in amygdala response to emotional stimuli 1 day after psilocybin treatment might be due to serotonergic adaptation (5 HT receptors) to treatment, that this study demonstrates is stabilized after 1 week

limitation: v small sample size

gregoretti668 — 2023-11-03 01:56:53 UTC