Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Neuro-pharmacology > GABA > Flashcards

GABA Flashcards

1
Q

GABA is the main

A

inhibitory neurotransmitter in the CNS (10-40% of
neurons in cortex, hippocampus, and substantia nigra)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

GABA increases the

A

conductance of chloride ions across cell
membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Glycine has

A

comparable but limited function as an inhibitory
neurotransmitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Gaba synthesis

A

glutamate –(GAD)–> GABA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Vesicular transport GABA and glycine share a

A

vesicular transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

GABA and glycine share a
vesicular transporter

A

Vesicular GABA transporter (VGAT) or vesicular inhibitory
amino acid transporter (IAAT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  • VGAT identifies both
A

GABAergic and glycinergic
neurons in the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Inhibitors of GABA are

A

convulsants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

GAD has several antagonists used experimentally (3)

A

allylglycine, thiosemicarbazide, and 3-mercaptopropionic
acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Inhibition of GAD

A

decreases GABA levels and leads to
convulsive activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Many drugs that decrease GABAergic activity are

A

limited in use to in vitro studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

GABA Transporters (GAT) are
found on

A

astrocyte and neuronal
membranes at the synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

GAT-1 is located on

A

neurons and
astrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

GAT-2 and -3 are principally

A

astrocytic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

GABAergic AEDs Tiagabine

A

is a selective antagonist of GAT-1 and elevates GABA
levels in the synapse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  • Tiagabine (Gabitril) is
A

approved as an adjunctive AED for epilepsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

GABAergic AEDs Vigabatrin

A

is an irreversible inhibitor of GABA-T and elevates GABA
levels in the brain by blocking breakdown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Vigabatrin (Sabril) is approved as

A

an adjunctive or primary AED for
epilepsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

GABA is

A

widespread through the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

GABA is widely used in

A

inhibitory interneurons throughout the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q
  • Chandelier cells of the cortex
    synapse onto the
A

axonal initial
segment of pyramidal cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q
  • Basket cells of the cerebellum,
    hippocampus, and cortex form
A

axo-somatic synapses onto target
cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

GABAergic neurons form

A

multiple
types of synapses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q
  • In addition to axo-dentritic
    synapses GABAergic
    synapses are often
A

axosomatic or axo-axonal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Axo-somatic synapses

A

control
excitability of cell body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Axo-axonal synapses

A

synapses at the
axon intial segment influence
signal integration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

GABAergic output from the cerebellum

A

Purkinje cells are large GABAergic projection neurons of
the cerebellum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q
  • Purkinje cells are large GABAergic projection neurons of
    the cerebellum
A

Provide the sole output of motor coordination from the
cerebellar cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Purkinje cells are under

A

inhibitory control from GABAergic
interneurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Degeneration of Purkinje neurons is termed

A

d Holmes
cerebellar degeneration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Holmes
cerebellar degeneration

A

Impaired fine hand movement, speech deficits, tremors, and
ataxia while walking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

GABAergic control of motor initiation Direct pathway

A

Excitatory input from cortex causes
excitation of upper motor neurons
in motor cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

GABAergic control of motor initiation Indirect pathway

A

Excitatory input from cortex causes
inhibition of upper motor neurons in
motor cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Dopaminergic
balance

A

Dopamine plays a gating role and balances
activity between the direct and indirect
pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Activation of nigrostriatal dopamine
pathways promotes the

A

direct pathway over the indirect pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

In Parkinson’s the loss of dopaminergic
projections shifts activity to the

A

indirect
pathway.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Cholinergic balance

A

Cholinergic interneurons in the
striatum receive excitatory inputs from
the cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Cholinergic interneurons act directly
on the

A

direct pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

M4AChR antagonists and AChE
inhibitors

A

are useful therapeutics in
early Parkinson’s as they compensate
for decreased dopaminergic input.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

GABA Receptors Two classes of GABA receptors

A

Ionotropic (GABA_A),
Metabotropic (GABAB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Ionotropic (GABAA) Classic

A

ligand gated ion channel permeable to Cl-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Ionotropic (GABAA) 5

A

subunits form the channel pore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Ionotropic (GABAA) Originally characterized by

A

y sensitivity to bicucculine (comp. antagonist)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Metabotropic (GABAB what type of preitein coupled receptors?

A

G-protein coupled receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Metabotropic (GABAB
) Gi

A

inhibits adenylate cyclase (↓ cAMP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Metabotropic (GABAB Gβγ

A

opens G-protein coupled K+ channel (GIRK

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Metabotropic (GABAB
) Originally characterized by

A

sensitivity to baclofen (specific agonist)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

GABAA * Pentameric channel

A

(5
-subunits) through
combination of 19 different genes`

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

how many types of alpha subunits

A

6 (GABARA1-6)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

how many types of beta subunits

A

3 β (GABARB1-3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

how many types of gamma subunits

A

3 γ (GABARG1-3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

how many types of other subunits

A

One each of δ (GABARD), ε (GABARE),
θ
(GABARQ),
π (GABARP)

53
Q

how many types of p subunits

A

3
ρ (GABARR)*

54
Q

Most common GABA
A channel

A

Most common is
α2β2γ

55
Q

Special case is GABA
Aρ which only forms

A

homopentameric channels with itself

56
Q

GABAA has ___ binding sites for

A

4, endogenous
and exogenous ligands

57
Q

GABAA has 4 binding sites for endogenous
and exogenous ligands GABA site

A

binds two molecules of GABA at
the interface between α and β subunits

58
Q

GABAA has 4 binding sites for endogenous
and exogenous ligands Benzodiazepine site

A

binds benzodiazepines
(tranquilizers) as positive allosteric modulators

59
Q

GABAA has 4 binding sites for endogenous
and exogenous ligands Barbiturate site

A

– binds barbiturates (sedative &
anxiolytics) as positive allosteric modulators

60
Q

GABAA has 4 binding sites for endogenous
and exogenous ligands Neurosteroid site

A

binds endogenous
neurosteroids as positive or negative allosteric
modulators

61
Q

Picrotoxin

A

is a non-competitive channel
blocker

62
Q

GABAA pharmacology Non-competitive sites

A

Pentylenetetrazol

63
Q

Pentylenetetrazol

A

l binds in the pore at the same site as picrotoxin and
was used as a convulsant for depression therapy

64
Q

Pentylenetetrazol Discontinued due to

A

high risks of spontaneous seizure

65
Q

GABAA pharmacology GABA site Competitive antagonist is

A

bicucculine

66
Q

bicucculine

A

potent convulsant

67
Q

GABA site Classic agonist is

A

muscimol

68
Q

Amanita muscaria (fly agaric)

A

Source of the muscarinic AChR agonist muscarine
Source of the GABAA agonist muscimol
Potent hallucinogen

69
Q

Consumption of fly agaric has serious

A

peripheral
side-effects due to muscarinic cholinergic effects at
NMJ and parasympathomimetic effects

70
Q

Gaboxidol is a

A

synthetic version of muscimol with
reduced psychotropic effects
Anxiolytic and analgesic
Investigated for insomnia treatment

71
Q

Benzodiazepines

A

Sedative-hypnotic, anxiolytic

72
Q

Diazepam

A

Benzodiazepines (Valium) one of the best known

73
Q

Benzodiazepines
Better safety margin than

A

barbiturates

74
Q

Benzodiazepines Binding

A

causes increased probability of pore
opening in creased chloride entering the cell

75
Q

Benzodiazepines High risks of drug interactions at the

A

GABAA
receptor

76
Q

Benzo Orphan receptor site

A

Endogenous ligand not known
Proposed ligands include inosine, peptides
such as diazepam binding inhibitor/acyl-CoA
binding protein, and small molecules called
endozepines

77
Q

Barbiturates

A

Sedative-hypnotic, anaesthetic

78
Q

Barbiturates best known

A

Phenobarbitol

79
Q

Barbiturates Narrow

A

safety margin

80
Q

Barbiturates Narrow safety margin

A

High potential for abuse
* High risk of overdose

81
Q

Barbiturates Binding prolongs open time of

A

Cl- pore

82
Q

Barbiturates Used in

A

physician-assisted suicide and
euthanasia

83
Q

Barbiturates Sodium amytal (amobarbital) is a

A

barbiturate
known as a ‘truth serum’

84
Q

Sodium amytal (amobarbital) is a barbiturate
known as a ‘truth serum’

A

Helps to circumvent inhibitions

85
Q

Other notable interactions of GABAAR Ethanol

A

is a potent positive allosteric modulator of GABAA binding
to a site on the transmembrane surface of the δ-subunit

86
Q

Ethanol exerts many of it’s

A

sedative, euphoric, and addictive effects
through modulation of GABAA

87
Q

Ethanol binds

A

GABAA with very high affinity – binding even at doses that
would be considered moderate, social levels

88
Q

Propofol is a potent

A

anaesthetic that interacts with the
transmembrane surface of the β-subunit of GABAA

89
Q

Propofol is a potent anaesthetic that interacts with the
transmembrane surface of the β-subunit of GABAA

A
  • Positive allosteric modulator that increases channel open time
90
Q

GABAB
receptors * Primarily affect excitability by
coupling to

A

GIRK

91
Q

GIRK activation is

A

s inhibitory by
allowing K+ efflux which
hyperpolarizes the cell

92
Q

GABAA is responsible for

A

fast, weak
inhibitory postsynaptic potential (IPSP)
signalling

93
Q

GIRK is responsible for

A

slow, strong
component of IPSP

94
Q

Baclofen is a specific

A

agonist of
GABAB and is a muscle relaxant
and antispastic

95
Q

γ-hydroxybutyric acid (GHB) is a

A

weak GABAB agonist

96
Q

γ-hydroxybutyric acid (GHB) is a
weak GABAB agonist Excitatory at the

A

GHB receptor at
lower doses → recreational drug use

97
Q

γ-hydroxybutyric acid (GHB) is a
weak GABAB agonist
* Excitatory at the GHB receptor at
lower doses → recreational drug use

A

euphoria, disinhibition, empathogenic

98
Q

γ-hydroxybutyric acid (GHB) is a
weak GABAB agonist Inhibitory at

A

GABAB at higher doses →
‘date rape drug’
Sedation, nausea, dizziness, and
unrouseable sleep

99
Q

G-protein coupled inward rectifying
K
+ channel (GIRK) K
+ channel activated during

A

GPCR
signalling

100
Q

G-protein coupled inward rectifying
K
+ channel (GIRK) GIRK opens on binding of

A

Gβγ (the
otherwise regulatory component of
the G-protein complex)

101
Q

G-protein coupled inward rectifying
K
+ channel (GIRK) K
+ exits the cell causing

A

hyperpolarization of the cell
membrane

102
Q

G-protein coupled inward rectifying
K
+ channel (GIRK) * GIRK signalling inhibits

A

subsequent
depolarizing stimuli

103
Q

GABAA
-ρ (rho) Receptor

A

– formed exclusively as a
homopentamer of the ρ-subunit (Clchannel)

104
Q

GABAA
-ρ (rho) Receptor Formerly considered

A

GABAC receptor

105
Q

GABAA
-ρ (rho) Receptor Insensitive to

A

baclofen and
bicucculine

106
Q

baclofen and
bicucculine

A

lacks binding sites for
benzodiazepines, barbiturates, and
neurosteroids

107
Q

GABAA
-ρ (rho) Receptor * More sensitive to

A

GABA (having 5
GABA binding sites)

108
Q

GABAA
-ρ (rho) Receptor Found in

A

bipolar cells of the retina

109
Q

GABAA
-ρ (rho) Receptor Found in bipolar cells of the retina

A

Receive inhibitory signals from amacrine
and horizontal cells

110
Q

Mutations in GABAA-ρ are associated
with

A

heritable cases of retinitis
pigmentosa

111
Q

Bipolar cells
(express

A

GABAA
-ρ )

112
Q

Amacrine cells Horizontal cells

A

Inhibitory neurons
(GABAergic)

113
Q

GABA development in the prefrontal cortex is a

A

late developmental
step and is associated with maturation of impulse control, working
memory, and executive function

114
Q

Behavioural effects of GABA Anxiety

A

Generalized anxiety disorder, social anxiety disorder, panic disorder, posttraumatic stress disorder

115
Q

GABA agonists and positive allosteric modulators are

A

anxiolytic

116
Q

Possible models of anxiety - Anxiety is caused by secretion of

A

endogenous inverse agonists of GABAR →
inhibition of GABAR increases anxiety?

117
Q

Possible models of anxiety - Ligand activity at

A

GABAR is shifted in anxiety (subunit alterations?)

118
Q

Possible models of anxiety - Secretion of

A

endogenous agonists of benzodiazepine site during stressful
conditions → deficit in anxiety disorders

119
Q

Behavioural effects of GABA Development

A

High levels of GABA and developmental changes in GABA
activity (excitatory / inhibitory switch)

120
Q

Development GABA may contribute to

A

cell proliferation, survival, and motility

121
Q

Development Excitatory / Inhibitory balance is important in

A

normal brain
development

122
Q
  • Excitatory / Inhibitory balance is affected in conditions such as
A

Down’s syndrome and Autism

123
Q

Behavioural effects of GABA Epilepsy

A

Excitatory / Inhbitory balance implicated in seizure disorders

124
Q

Drugs that decrease GABA levels or inhibit GABAR function are

A

convulsant

125
Q
  • Drugs that increase GABA levels or increase GABAR function are
A

anticonvulsant

126
Q
  • E/I imbalance in Down’s syndrome and Autism correlate with
A

increased risk of seizure disorders

127
Q

Behavioural effects of GABA Psychiatric disorders

A

GABA has been implicated or suggested to play a role in numerous
neuropsychiatric & neurodegenerative disorders

128
Q

sychiatric disorders
* GABA has been implicated or suggested to play a role in numerous
neuropsychiatric & neurodegenerative disorders

A
  • Developmental disorders (ASD)
  • Addiction
  • Learning disorders
  • Schizophrenia
  • Tardive dyskinesia
  • Huntington’s disease
  • Parkinson’s disease
129
Q

Behavioural effects of GABA
* Psychiatric disorders Generally proposed to contribute to

A

hyperactivity through decreased
inhibitory signalling

Neuro-pharmacology (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions