Postsynaptic Flashcards

1
Q

entry of sodium in post synaptic neuron causes

A

depolarisation

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2
Q

structure of a dendritic spine

A

small membranous protrusion from a neuron dendrite that typically receives input from a single axon at the synapse
dendritic spine = spine neck + spine head
storage sites for synaptic strength and help transmit electrical signals to the neuons cell body

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3
Q

why are dendritic spines important

A

functional compartmentalisation
ionic and biochemical changes are partially restricted to just the activated synapse - input specificity

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4
Q

post synaptic density

A

neurotransmitter receptors and anchored and regulated by a host protein

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5
Q

where do eneurons receive inputs

A

somato dendritic compartments

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6
Q

how is L Glutamate synthesised

A
  • non essential amino acid
  • synthesised from glutamine via glutaminase
  • most abundant excitatory neurotransmitter
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7
Q

injected intracerebral glutamate results in

A

seizures
shown by Hayashi

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8
Q

where is glutamate stored

A

synaptic vesicles

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9
Q

how is glutamate transported into vesicles

A

VGLUT transfers cytosolic glutamate into vesicle

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10
Q

how is glutamate released

A

calcium dependent release mechanism

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11
Q

glutamate receptors

A

specific protein targets
iGluRs
mGluRs

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12
Q

where are glutamate transporters present

A

pre and post synaptic nerve terminals and astrocytes (EAAT1/2)
rapid removal of transmitter from synapse

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13
Q

process for glutamate synthesis

A

glutamate-glutamine shuttle and metabolic processes within presynaptic terminal

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14
Q

2 main types of ionotropic receptors

A

AMPA
NMDA

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15
Q

AMPA receptor role

A

day to day business of synaptic communication
they are permeable to sodium and potassium ions but do not usually pass calcium ions

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16
Q

NMDA receptor role

A

activated under special conditions
pass calcium ions as well as sodium and potassium
this calcium flux allows local biochemical changes to be triggered when the receptors are activated

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17
Q

structure of a single iGluR subunit

A

extracellular = N terminus and ligand binding domain
Intracellular = C terminus

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18
Q

Glu subunits in AMPA

A

mixtures of gutA1-4

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19
Q

why do most AMPA receptors contain GluA2

A

endows calcium impermeabile to the pore

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20
Q

example antagonists of AMPA receptors

A

NBQX
CNQX

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21
Q

Glu subunits in NMDA receptors

A

mixtures of GluN1 and GluN2 - must have both

22
Q

calcium and NMDA receptors

A

calcium permeable pore
voltage dependent magnesium block

23
Q

example antagonist of NMDA receptors

24
Q

are NMDA and AMPA tetrameric and heterotetramers

A

NMDA and AMPA = tetrameric assemblies
NMDA = always heterotetramers
AMPA = usually heterotetramets

25
what is fast synaptic transmission mediated by
ionotropic receptors
26
EPSP of AMPA receipts
high amplitude short lived EPSP
27
when is the magnesium block on NMDA channel removed
at a voltage of - 35nV (depolarising potentials = magnesium block is removed
28
NMDA receptor EPSP
NMDA receptor mediated a slow rising long lasting EPSP = via sodium and calcium entry through channel
29
one inside the cell what can calcium cause
calcium can activate enzymes regulate ion channel opening and affect gene expression result in changes to synaptic strength -> synaptic plasticity
30
GABA full name and role
gamma-amino butyric acid major inhibitory neurotransmitter in the brain
31
what are the2 classes of GABA receptor
GABA (a) - ionotropic - fast GABA (b) - metabotropic - slow
32
how is GABA synthesised from glutamate
Glutamte + glutamate decarboxylase = GABA
33
where is GABA stored
synaptic vesicles
34
how is GABA transported to vesicle
transporter VGAT transfers cytosolic GABA into vesicle
35
how is GABA vesicle
calcium dependent release
36
where are GAT1 and GAT3 transporters present
pre and post synaptic nerve terminals process for rapid removal of transmitters from synapse GABA transporters
37
what are the 2 isodorms of glutamate decarboxylase (GAD)
GAD67 - through cell GAD65 - nerve terminal
37
what are the 2 isodorms of glutamate decarboxylase (GAD)
GAD67 - through cell GAD65 - nerve terminal
38
wants the key difference between location of GABAergic and glutamergic synapses
GABAergic synapses do not usually occur on dendritic spines
39
structure of GABA(a) receptors
pentameric ligand acted chloride channels 4 transmembrane domains 5 subunits - 2xalpha, 2xbeta, gamma
40
what transmembrane protein forms the pore of GABA channel
TM2
41
what ion causes hyperpolasiation through GABA receptors
chloride ions - flow down EC gradient into the cell = hyperpolarise the cell
42
what receipts are most widely used for synaptic inhibition
GABA(a)
43
what happens when GABA binds to GAbA a receptors
cholride ions flow inside produce fat inhibitor postsynaptic potential (IPSP)
44
what type of receptor are GABAG (b)
heterodimeric GPCR - metabotropic receptor slower
45
how do GABA (b) receptors work
GPCR inhibits voltage gated calcium channel modulate the activity of adenylyl cyclase and amount of cAMP = suppress downstream effects slower IPSP
46
where are GABA b receptors commonly found
pre synaptic terminals
47
why does activation of GABA b receptors produce sloe IPSP
works via second messengers - slower
48
what does co activation of GABA a and GABA b produce
long lasting biphasic IPSPs
49
what is an autoreceptor
receptor on presynaptic terminal - activated by the neurotransmitter released by the synapse
50
what can the presence of GABAb auto receptors lead to
form of paired pulse depression 2 identical presynaptic stimuli are given in rapid succession - second IPSP is smaller
51
why do GABA b auto receptors lead to paired pulse depression
- activation of presynaptic GABAb receptors is negatively coupled to voltage gated calcium channels - restricts Ca2+ entry to presynaptic cell - conditioned (2nd) stimuli results in reduced Ca2+-dependent exocytosis --> less GABA released