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psyc 462 > lecture 7 LOs > Flashcards

lecture 7 LOs Flashcards

1
Q

what projection neurons use glutamate

A

all pyramidal cells in cerebral cortex
projection neurons of hippocampus, amygdala, thalamus
glutamate projection neurons embedded in other subcortical neclei

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2
Q

what is glutamate ionized by

A

the amino acid glutamic acid

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3
Q

what does glutamate serve as and what is it a component of

A

serves as a neurotransmitter
component of many proteins and has other metabolic roles

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4
Q

what is glutamate synthesized by

A

glutamine by glutaminase

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5
Q

what vesicular transport moves glutamate into synaptic vesicles

A

VGLUT

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6
Q

where are VGLUT transporters found

A

in glutaminergic neurons

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7
Q

what is VGLUT the primary marker for

A

neurons that use glutamate as a neurotransmitter

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8
Q

what else can VGLUT be expressed with

A

markers of other transmitters, implying that glutamate can be stored and released as a co transmitter (as well as a primary transmitter)

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9
Q

what happens after glutamate release

A

it is rapidly removed from the synapse by excitatory amino acid transporters (EAAT1 to EAAT5)

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10
Q

where is EAAT1 found

A

on astrocyte glia (90% of glutamate reuptake)

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11
Q

where is EAAT3 found

A

on post synaptic membranes

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12
Q

what are astrocyte transporters involved in

A

glia-neuron metabolic partnership

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13
Q

majority of glutamate reuptake is done by ____ and then what does it do

A

astrocytes
then convert glutamate to glutamine by glutamine synthesis

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14
Q

where is glutamine transported after glutamine synthesis

A

out of astrocyte and back to neuron

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15
Q

three subtypes of ionotropic gluatmate receptors

A

AMPA - named for selective agonist
Kainate - named for selective agonist Kainic acid
NMDA - named for an agonist

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16
Q

how many sub unit proteins do ionotropic receptors consist of

A

four, but each of the three receptor subtypes have different combos to explain the differences in their pharmacology

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17
Q

what does activation of AMPA/kainate receptors allow the entry of

A

Na+, depolarizes the neuron

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18
Q

how are AMPA/kainate activated

A

always activated when there are sufficient stimulation by glutamate

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19
Q

what happens to AMPA/Kainate when too much stimulation occurs

A

receptor desensitization

20
Q

what does NBQX do to receptors

A

a competitive antagonist that blocks both AMPA and Kainate receptors

21
Q

what is the result of NBQX

A

sedation, reduced locomotor activity, ataxia, potection against seizures

22
Q

what does NMDA allow into the neuron

A

both Na+ and Ca2+
causes greater depolarization than AMPA/Kainate

23
Q

what is required to open the NMDA channel

A

both glutamate and glycerine or D-serine must bind at the same time (co-agonists)

24
Q

when the NMDA neuron is at rest, what is blocking the channel

A

Mg2+

25
Q

what does repeated AMPA receptor activation do

A

can depolarize the neuron enough to remove Mg2+ blockage and allow NMDA receptor to activate

26
Q

what does AP-5 do

A

competitve antagonist that blocks glutamate binding

27
Q

what blocks the NMDA channel when it is open

A

phencyclidine (PCP), ketamine, and MK-801

28
Q

what can phencyclidine (PCP), ketamine, and MK-801 cause for symptoms

A

schizophrenia like symptoms at lower doses
ataxia (inability to move) and anesthesia at higher dose

29
Q

what do drugs that target the glycine binding site do

A

act as a non competitve antagonist

30
Q

does NMDA or AMPA/Kainate cause larger/longer lasting depolarization

A

NMDA

31
Q

what does NMDA receptor activity do to the neuron

A

depolarize it
alter firing patterns (promote burst firing)

32
Q

metabotropic glutamate receptors

A

mGluR1 to mGluR8
act through G-proteins and second messenger systems

33
Q

which of the mGluR are postsynaptic and which are presynaptic

A

mGluR1 and 5 are postsynaptic
mGluR2-4 and 6-8 are presyanptic

34
Q

what do presynaptic mGlurRs act as

A

autoreceptors or heteroreceptors
suppress glutamate release (or release of other transmitters)

35
Q

what is L-AP4

A

agonist at mGluR 4,6,7,8 autoreceptors

36
Q

what does L-AP4 do

A

treatment with this frug reduces glutamate signalling by depressing release

37
Q

what do mGluRs participate in

A

functions such as locomotion, motor coordination, cognition, mood and pain perception

38
Q

how are alterations in the activity of synapses measured

A

synaptic strength

39
Q

how is synaptic strength measured and what does it mean

A

typically measured by changes in post synaptic potential evoked by an input
increased strength = larger EPSP evoked in postsynaptic neuron
primarily measured with electrophysiological methods

40
Q

steps of long term potentiation

A

1: stimulate presynaptic axons at low frequency to get subthreshold EPSP (no AP), establish baseline
2: stimulate axons at very high frequency and get lots of AP in post synaptic neuron
3: axons at low frequency again, same subthreshold current = much bigger EPSP than before

41
Q

early phase LTP

A

high frequ activation of postsynaptic neuron allows NMDA receptor to be activated (Ca2+ entry into neuron)
ca2+ activates enzymes (kinases) including calcium-calmodulin (CaM)
CaM kinase hits AMPA receptor floating in the cell and insterts in the membrane (resulting in more receptors)
other kinases (protein kinase C) can induce formation of retrograde messenger (molec that goes from postsynaptic neuron to presynaptic terminal, promotes transmitter release)
dendritic spines undergo structural change to be more excitable
increased synaptic strength by both pre and post synaptic mechanisms

42
Q

what happens in late phase LTP

A

cell synthesizes new proteins that make the changes longer lasting

43
Q

what does a blockade of NMDA receptors impair

A

many forms of learning mediated by different systems (hippocampus, amygdala, striatum)

44
Q

when glutamate activity is slightly enhanced what happens

A

can improve learning/memory

45
Q

what does ampakine do

A

positive allosteric modulator of AMPA receptor, increases cognition in normal animals and in animal models w cognitive dysfunction

psyc 462 (21 decks)

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