Chapter 8: Glutamate & GABA Flashcards

1
Q

Glutamate (Glu) is the main […] in the CNS.

A

excitatory NT

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2
Q

Glu is the […] form of glutamic acid.

A

ionized

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3
Q

Glutamatergic neurons use […] as an NT and are one of the most […] neural populations in the brain particularly through the […].

A

glutamate; abundant; cortex

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4
Q

Describe glutamate synthesis:

A

synthesized from glutamine by enzyme known as glutaminase

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5
Q

Is ATP required for glutamate synthesis?

A

yes

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6
Q

T/F: Glutamate can be co-expressed.

A

true

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7
Q

Dopaminergic neurons in the ventral tegmental area typically co-express…

A

dopamine and glutamate

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8
Q

What are VGLUTs?

A

vesicular glutamate transporters

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9
Q

Role of VGLUTs:

A

move glutamate into synaptic vesicles

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10
Q

VGLUTs are only found in […] neurons. This means they serve as […].

A

glutamatergic; genetic markers

**identify the type of neurons

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11
Q

List the VGLUTs types:

A

VGLUT1-3

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12
Q

VGLUT1 removed in KO mice:

A

survive birth but begin to die during the third week of life

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13
Q

VGLUT2 removed in KO mice:

A

die immediately after birth

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14
Q

VGLUT3 removed in KO mice:

A

viable, but completely deaf; the inner hair cells of the cochlea use glutamate as a NT

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15
Q

EAATs:

A

excitatory amino acid transporters

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16
Q

Roles of EAATs:

A

remove glutamate from the synaptic cleft

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17
Q

Where are EAATs located?

A

different locations

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18
Q

EAATs have a partnership with […].

A

astrocytes

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19
Q

EAATs on astrocytes mediate […]. Astrocytes convert […] into […] by […] synthetase. […] is transported out of astrocytes and back into neurons.

A

glutamate uptake; glutamate; glutamine; glutamine synthetase; glutamine

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20
Q

EAAT2 removed in KO mice:

A

exhibit spontaneous epileptic seizures and die after 2-3 weeks of age

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21
Q

List the ionotropic glutamate receptors (GluRs):

A
  1. AMPA receptors
  2. kainate receptors
  3. NMDA receptors
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22
Q

List the metabotropic glutamate receptors (mGlus):

A

Group I-III

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23
Q

AMPA receptors = named for the selective agonist […]

Kainate receptors = named for the selective agonist […]

NMDA = named for the agonist […]

A

AMPA (a synthetic AA)

kainic acid

NMDA (a synthetic AA)

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24
Q

Metabotropic glutamate receptors: What are the Group I receptors? Where are they located (pre/post)?

A

mGlu 1 and 5

mainly postsynaptic

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25
Q

Metabotropic glutamate receptors: What are the Group 2 receptors? Where are they located (pre/post)?

A

mGlu 2 & 3

mainly presynaptic

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26
Q

Metabotropic glutamate receptors: What are the Group 3 receptors? Where are they located (pre/post)?

A

mGlu 4, 6, 7, 8

mainly presynaptic

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27
Q

AMPA receptors are also known as…

A

GluR and GluA

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28
Q

AMPA receptors have […] subunits: GluR[…].

A

4; 1-4

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29
Q

AMPA subunits form […]. The most common ones in the adult mammalian CNS are GluA 2/3 and […].

A

dimers; GluA 1/2

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30
Q

[…] blocks AMPA and kainate, but not NMDA receptors.

A

NBQX

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31
Q

Rats treated wth NBQX exhibit sedations, […], and protection against […].

A

ataxia (reduced locomotion); seizures

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32
Q

NMDA receptors provide ion flow for both […] and […].

A

Na+; Ca2+

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33
Q

NMDA receptors are also known as …(2).

A

NMDA or GluN

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34
Q

Opening of the channel with NMDA receptors requires […] and […].

A

co-agonists; depolarization

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35
Q

What are the co-agonists that are required for NMDA receptors?

A

glutamate and glycine/D-serine

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36
Q

Depolarization at a NMDA receptor expels…

A

Mg2+ blockage (pore blocker)

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37
Q

All drugs that block the NMDA channel are […].

A

non-competitive agonists

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38
Q

Drugs of abuse that block the NMDA channel:

A
  1. PCP
  2. ketamine
  3. memantine
39
Q

How many subunits for metabotropic glutamate receptors?

A

8

40
Q

Metabotropic glutamate receptors use […] and […].

A

G-proteins; second messengers

41
Q

Metabotropic Glu receptors: Some subunits inhibit […]. Some subunits activate […].

A

cAMP; IP3/DAG

42
Q

Metabotropic Glu receptors: Some subunits act as pre-synaptic […] to inhibit […] release.

A

autoreceptors; glutamate

43
Q

T/F: mGluRs are widely distributed throughout the brain.

A

true

44
Q

Which type of drugs is being developed to treat the neuropsychiatric disorder known as fragile X syndrome?

A

mGluR drugs

45
Q

Group I of metabotropic glutamate receptors (Gs/Gi/Gq)?

A

Gq

46
Q

Group II of metabotropic glutamate receptors (Gs/Gi/Gq)?

A

Gi

47
Q

Group III of metabotropic glutamate receptors (Gs/Gi/Gq)?

A

Gi

48
Q

What is GABA?

A

the main inhibitory amino acid transmitter in the CNS

49
Q

What is similar to GABA? How much of the spinal cord utilizes this NT?

A

glycine; 1/2 of the inhibitory synapses use glycine

50
Q

T/F: Inhibitory NT is just as important as excitatory.

A

true; blocking GABA receptors results in convulsions and death

51
Q

GABA synthesis occurs from the conversion of […] to GABA by the […] enzyme.

A

glutamate; glutamic acid decarboxylase (GAD)

52
Q

Only […] neurons have GAD.

A

GABAergic

53
Q

Can just any neuron synthesize GAD?

A

no only GABAergic neurons can

54
Q

Drugs that affect GABA synthesis typically block […].

A

GAD

55
Q

Drugs that block GAD:

A
  1. allyglycine
  2. thiosemicarbazide
  3. 3-mercaptopropionic acid
56
Q

What are VGATs?

A

vesicular GABA transporters

57
Q

What is the role of VGATs?

A

transporters to move GABA into vesicles

58
Q

What are some other names for VGATs?

A

VIAATs (vesicular inhibitory amino acid transporters)

**they also transport glycine

59
Q

What are GATs?

A

GABA transporters

60
Q

What is the role of GATs?

A

transporters to remove GABA from the synaptic cleft

61
Q

What is one drug that affects GATs?

A

tiagabine

62
Q

Tiagabine affects GATs by… it results in…

A

selectively inhibiting GAT-1

this elevates the EC GABA

63
Q

Tigabine is marketed as […] for treating […].

A

Gabitirl; epilepsy

64
Q

GABA-T stands for…

A

GABA aminotransferase

65
Q

GABA-T […] GABA back to […] (and succinate) in GABAergic neurons and astrocytes.

A

metabolizes; glutamate

66
Q

What is the name of the drug that affects GABA-T?

A

Vigabatrin (Sabril)

67
Q

Viagabatrin is a […] of GABA-T that prevents GABA […]. Build up of GABA levels in the brain has […] effects, thus, it is used to treat forms of […].

A

irreversible inhibitor; metabolism; anticonvulsant; epilepsy

68
Q

GABA can be coreleased by many neuron types, including those that produce… (6)

A
  1. ACh
  2. DA
  3. SOM, SST
  4. PV
  5. CCK
  6. VIP
    etc.
69
Q

T/F: Populations of neurons co-release GABA and glutamate.

A

true SOME populations can

70
Q

Co-releasing GABA and glutamate can allow […] of postsynaptic responses.

A

fine-tuning

71
Q

How much (%) of cortical neurons use GABA as a NT?

A

10-20%

72
Q

How much (%) of the hippocampus neurons are GABAergic?

A

10-40%

73
Q

Hippocampus is important for […].

A

memory function

74
Q

How much (%) of the substantia nigra neurons are GABAergic?

A

40-60%

75
Q

Substantia Nigra is the…

A

midbrain DA center

76
Q

Locations where GABA is found:

A
  1. cortex
  2. hippocampus
  3. substantia nigra
  4. basal ganglia
  5. micro/macro circuits
77
Q

Microcircuits are […] brain regions while macrocircuits are […] brain regions.

A

within; between

78
Q

GABAergic neurons of the striatum (STR) project to the […] and […].

A

globus pallidus (GP); substantia nigra (SN)

79
Q

When […] input to the stratum is damaged in Parkinson’s disease, the result is abnormal firing of striatal GABAergic neurons.

A

DA

80
Q

GABAa receptors are…

A

ionotropic

81
Q

GABAa channels allow […] ions into neurons. This causes […] and […] of postsynaptic cells.

A

Cl-; hyperpolarization; inhibition

82
Q

Each GABAa receptor has […] subunits of four types.

A

5

83
Q

GABAb receptors are…

A

metabotropic

84
Q

GABAb receptors require […] subunits to assemble in the membrane.

A

2

85
Q

GABAb receptors have inhibitory effects on postsynaptic cells by inhibiting […] and […] opening.

A

cAMP; K+ channel

86
Q

A classic agonist for GABAa is […].

A

muscimol

87
Q

[…] is a competitive antagonist for GABAa receptors.

A

Bicuculline

88
Q

Bicuculline is a competitive antagonist for GABAa receptor. It […] the binding site and has potent […] effects.

A

blocks; convulsant

89
Q

GABAa reacts to CNS […] drugs.

A

depressant

90
Q

Barbituates, benzodiazepines, ethanol and GABAa:

A

potentiating the effects of GABA NT on GABAa receptors

**positive allosteric modulation

91
Q

Agonist for GABAb receptor:

A

baclofen

92
Q

Antagonists for GABAb receptors:

Are they competitive?

A

saclofen and 2-hydroxysaclofen

yes

93
Q

Functions of GABAb in the CNS

A
  1. learning and memory
  2. anxiety-like behaviors
  3. depression-like behaviors
  4. responses to drugs of abuse