Neurotransmitters and their Receptors Flashcards
1
Q
Chemical signaling consists of a _____, a _____, and a _____.
A
neurotransmitter
receptor
ion channel
2
Q
Acetylcholine is an _____ neurotransmitter.
A
excitatory
3
Q
Glutamate is an _____ neurotransmitter.
A
excitatory
4
Q
GABA is an _____ neurotransmitter.
A
inhibitory
5
Q
Glycine is a _____ neurotransmitter.
A
inhibitory
6
Q
Catecholamines (_____, _____, _____) are _____ neurotransmitters.
A
epinephrine
norepinephrine
dopamine
excitatory
7
Q
Serotonin is an _____ neurotransmitter.
A
excitatory
8
Q
Histamine is a _____ neurotransmitter.
A
excitatory
9
Q
Ionotropic receptors are _____ channels.
A
ligand-gated
10
Q
Metabotropic receptors are _____ receptors.
A
G-protein-coupled
11
Q
Ionotropic Receptors (types)
A
- Glutamate receptors (NMDA,AMPA/Kainate)
- Nicotinic acetylcholine receptor (nAChR)
- 5-HT(sub3) receptor
- GABA(subA) receptor
- Glycine receptor
- Purinergic receptors
12
Q
G-protein coupled receptors are _____ proteins consisting of ______ transmembrane
domains.
A
monomeric
7
13
Q
Domains ,,_,and _ of GPCRs make up the
neurotansmitter binding region.
A
II, III, VI, and VII
14
Q
G-proteins bind to both the loop between domains _ and _ and the _____.
A
V
VI
C-terminus (string from helix-7)
15
Q
Biogenic Amines
A
DA EPI NE Histamine Serotonin
16
Q
nAChR consists of _ subunits.
Muscles: _____
Neurons: _____
A
5
αα:β:γ:δ
ααα:ββ
17
Q
In nAChR, the _____ bind acetylcholine.
A
α-subunits
18
Q
Each subunit of the nAChR consists of _
transmembrane spanning _____.
A
4
α-helices
19
Q
The _____ surround the channel of the nAChR.
A
M2 subunits
20
Q
Binding of acetylcholine to the two alpha subunits
results in a _° rotation of all _____ helices.
A
15
M2
21
Q
The cytoplasm side of the nAChR receptor has
rings of high _____ charge that determine the
_____ of the receptor and remove the
_____ of the passing ions.
A
negative
cation specificity
hydration shell
22
Q
Binding of _ ACh molecules results in a _____ of the M2 helices
A
2
twisting
23
Q
The nAChR is a _____
cation channel.
A
non-selective
24
Q
Higher driving force for _____ typically results in an _____ current and an _____.
A
Na+
inward
EPSP
25
Precursors of acetylcholine
Acetyl coenzyme A
| choline
26
The enzyme _____ catalyzes Acetylcholine.
choline acetyltransferase (ChAT)
27
_____ load ~_ ACh molecules into each vesicle.
Vesicular ACh transporters
| 10
28
After release into the synapse, _____ breaks up ACh into
| _____ and _____.
acetylcholinesterase
acetate
choline
29
A _____ transporter
| takes choline back up into the presynaptic terminal.
Na+/choline
30
Myasthenia gravis is treated with
reversible acetylcholine-esterase inhibitors (e.g. neostigmine)
31
Myasthenia Gravis is the result of ____ caused by ____.
an autoimmune response
circulating antibodies that block AChRs at the post-synaptic neuromuscular junction
32
ACh has difficulty binding due to _____ of the binding site.
IgG blockade
33
Irreversible Acetylcholinesterase inhibitors
completely inhibit ACh breakdown
34
Treatment of acetylcholinesterase inhibition involves combined administration of a _____ and the AChE antagonist _____.
muscarinic receptor antagonist (atropine)
pralidoxime
35
neurotoxins such as snake poisins, curare (plant) and conotoxins (cone snails) are _____.
nAChR antagonists
36
Chewing betel nuts releases _____, a nicotinic agonist.
arecoline
37
Enzyme _____ catalyzes glutamate from glutamine
glutaminase
38
VGLUT
vesicular glutamate transporter
39
EAAT
excitatory amino acid transporter
40
precursor of glutamate
glutamine
| released by glial cells
41
glutamate receptors are _____.
non-selective cation channels
42
NMDA-R serves as a _____.
coincidence detector
43
NMDA-Rs require _____ as co-agonist.
glycine
44
NMDA current involvement in an action potential is maximized with ____.
no Mg2+ block
45
Ca2+ influx through NMDA-Rs results in
| _____ and eventually _____ and ____.
AMPA-R phosphorylation (early phase)
gene transcription
protein synthesis
(late phase)
46
mGluRs have _____ and can be _____ or _____
slow responses
excitatory
inhibitory
47
mGluR group 1
(mGluRs 1 and 5)
| excitatory, G(q) coupled
48
mGluR group 2
(mGluRs 2 and 3)
| inhibitory, G(i/o) coupled
49
mGluR group 3
(mGluRs 4, 6, 7, and 8)
| inhibitory, G(i/o) coupled
50
Group I mGluRs increase _____ and are mostly _____.
NMDA
| postsynaptic
51
Group II mGluRs reduce _____, decrease _____ release, and decrease _____.
cAMP
transmitter
NMDA
52
Group II mGluRs are mostly _____ and on _____.
presynaptic
| glia cells
53
Group III mGluRs reduce _____, decrease _____ release, and decrease _____.
cAMP
transmitter
NMDA
54
Group III mGluRs are mostly _____.
presynaptic
55
GAD
glutamate decarboxylase;
| catalyzes glutamate to GABA
56
VIAAT
vesicular inhibitory amino acid transporter
57
GAT
GABA transporter (removal from synaptic cleft)
58
Ionotropic GABA receptors
GABA(A) and GABA(C)
59
The effects of GABA agonists (e.g. benzodiazepines [Valium] and barbiturates)
* anxiolytic (anxiety-reducing)
* anesthetic
* sedative-hypnotic
* anti-convulsive
60
Both _____ or _____ facilitate the ability of GABA to activate the receptor and opening of the chloride channel.
benzodiazepines
| barbiturates (or alcohol)
61
Barbiturates increase the _____.
length of channel openings
62
Benzodiazepines increase the _____.
frequency of channel openings
63
Depolarizing synaptic potentials can inhibit neurons as long as the _____ is more hyperpolarized (negative) than the _____.
E(Cl-)
| action potential threshold
64
In developing neurons the intracellular Cl- concentration is controlled by the _____, yielding high intracellular levels of _____.
Na+/K+/Cl- co-transporter
| Cl-
65
In adult cells a _____ pumps Cl- out of the cell, lowering the _____, making ECl- much more negative (leads to hyperpolarization).
K+/Cl- co-transporter
| internal Cl-
66
Shunting inhibition
If ECl- is equal to RMP, opening of Cl- channels does not hyperpolarize the cell, yet will act inhibitory on simultaneous EPSPs
67
Metabotropic GABA receptors
GABA(B)
68
mGABAR stimulate _____, leading to _____.
opening of K+ channels
| hyperpolarization
69
mGABAR inhibit _____, leading to _____.
Ca2+ channels
| hyperpolarization
70
mGABAR have _.
7 transmembrane domains
71
Activation of presynaptic GABA(B) autoreceptors can inhibit release of _____ from the terminal.
GABA
72
Presynaptic GABA(B) receptors inhibit release of ___, ___, and ___.
dopamine
norepinephrine
serotonin
73
catecholamines are released by the _____ in response to psychological stress or low blood sugar levels.
adrenal glands
74
Effects of catecholamines typically include
increases in heart rate
blood pressure
blood glucose levels
general reaction of the sympathetic nervous system
75
In the CNS, catecholamines act as _____, influencing the effects of other classical neurotransmitters.
neuromodulators
76
_____ catalyzes the reaction of L-Tyrosine to L-DOPA.
Tyrosine Hydroxylase
| TH
77
_____ catalyzes the reaction of L-DOPA to DA.
Aromatic L-amino acid decarboxylase
| AADC
78
_____ catalyzes the reaction of DA to NE.
Dopamine B-Hydroxylase
| DBH
79
_____ catalyzes the reaction of NE to EP.
Phenylethanolamine N-Methyltransferase
| PNMT
80
Catecholamines do not evoke EPSP or IPSP by themselves, rather make EPSP / IPSP _____.
larger or smaller
81
Catecholamines alter ion channels to modulate _____, so that when synaptic inputs arrive the neuron is either _____ or _____.
cell’s excitability
more ready to fire action potentials
hyperpolarized / less excitable
82
The catecholamine _____ is the reate-limiting enzyme in the synthesis of all catecholamines.
tyrosine hydroxylase
83
Tyrosine hydroxylase is upregulated by _____, _____, _____, and _____.
stress
caffeine
nicotine
morphine
84
Tyrosine hydroxylase is downregualted by _____.
antidepressants
85
Symptoms of parkinson's disease
```
tremors
muscle rigidity
akinesia
bradykinesia
postural instability
```
86
Treatment of parkinson's disease involves the replacement of lost DA with _____ or _____.
L-DOPA
| DA
87
GABAergic neurons in the _____ are the origin of projections that control (disinhibit) the thalamus, which in turn controls areas in the cortex that _____.
striatum
| initiate movement
88
Parkinson's Disease
Loss of DA inhibition of GABAergic projection neurons.
89
Addictive drugs target the _____, which includes the dopaminergic projections from the ventral tegmental area (VTA) to the _____ and other forebrain structures.
brain reward circuit
| nucleus accumbens
90
Dependence
an adaptive state that develops in response to repeated drug administration
91
Cessation of drug use can lead to ____.
withdrawal symptoms
92
Tolerance
refers to the diminished effect of a drug after repeated administration at the same dose, or the need to increase the dose to produce the same effect.
93
sensitization
repeated drug administration leads to stronger effects at the same dose.
94
Drugs of abuse typically release _-_ times the amount of dopamine that natural rewards do.
2
| 10
95
VMAT
vesicular monoamine transporter
96
DAT
Dopamine transporter
97
COMT
catechol O-methyltransferase
| enzyme that degrades all catecholamines
98
MAO
monoamine oxidase, enzyme that degrades all monoamines
99
HVA
homovanillic acid
100
Cocaine and amphetamines inhibit _____.
the re-uptake of dopamine
101
Cocaine blocks _____ which increases the lifetime of dopamine in the synaptic cleft.
the dopamine transporter (DAT) (blocks dopamine re-uptake)
102
Amphetamines increase _____ and block _____.
dopamine release
| re-uptake
103
Amphetamines enter the presynaptic terminal (via DAT, or through direct diffusion) and release _____ from the vesicles by making the dopamine transporters _____.
dopamine
| work in reverse
104
NE forms at the _____.
locus coeruleus
105
EP forms at _____.
meduallary epinephrine neurons
106
_____ catalyzes the reaction of DA to NE.
Dopamine B-Hydroxylase
107
NET
NorEpinephrine Transporter
108
NE and EP are degraded by ____.
MAO
109
MAO
enzyme that degrades all monoamines
110
NE and EP act _____ on 2 types of GPCRs: ____ and ____.
postsynaptically
A-
B-Adrenergic Receptors
111
_____ inhibits VMAT and depletes NE stores.
Reserpine
112
_____ inhibits COMT.
Tropolone
113
_____ inhibits tyrosine hydroxylase and NE synthesis.
AMPT
114
_____ is a norepinephrine and dopamine reuptake inhibitor.
Methylphenidate (Ritalin)
115
Clonidine is an _____.
α2 adrenergic agonist
116
α2-receptors are _____ (inhibits NE release).
autoreceptors (presynaptically)
117
5 groups of Neuropeptides:
* brain / gut peptides
* Opioid peptides
* Pituitary peptides
* Hypothalamic releasing hormones
* “other peptides”
118
Pre-propeptides are present on the _____.
rough ER
119
Propeptides are present on the _____.
trans-Golgi network
120
Can different peptides can be released from the same vesicle?
yes
121
Morphine, heroin, and synthetic opiates such as methadone and fentanyl are potent _____.
analgesics
122
3 groups of endogenous opioid receptor ligands:
* Endorphins (ENDOgenous moRPHINE)
* Enkephalins
* Dynorphins
123
Enkephalins, endorphins and dynorphins are released in the _____.
periaqueductal gray
124
Enkephalins are also released directly in the spinal cord to blunt the effects of _____.
nociceptor (C-FIBER) activation
125
The _____ have a high affinity for enkephalins and beta-endorphin, but low affinity for dynorphins.
μ opioid receptors
126
Morphine (heroin) and codeine bind to _____.
μ opioid receptors
127
Main locus of action of heroin and codeine is in the _____.
VTA
128
______ is the main active component of marijuana.
tetrahydrocannabinol (THC)
129
Endocannabinoids:
2-AG
| anandamide
130
2 types of cannabinoid receptors (G-protein coupled receptors):
* CB1 mainly expressed in the CNS and
| * CB2 mainly expressed in immune cells
131
low doses of cannabinoids tend to reduce _____, whereas high doses _____ theses behaviors.
anxiety-like behaviors
| increase
132
Anxiolytic effects:
* Euphoric feelings of happiness, talkativeness, dream-like state.
* Feelings of dizziness or fuzziness.
* Contagious laughing or joking
* Increases appetite “munchies”
133
THC has _____ as seen in studies with drug discrimination, brain stimulation reward, and intravenous self-administration.
acute reinforcing effects
134
THC increases the release of dopamine in the shell of the _____.
nucleus accumbens
135
Physiological effects of (Endo-) cannabinoids
Various effects, including
• inhibition of adenylate cyclase,
• modulation of voltage-dependent calcium, and
• potassium channels
136
Enhancement of endocannabinoid signaling produces _____.
anxiolytic and antidepressant-like effects
137
endocannabinoid system is involved in the regulation of ____.
emotional states
138
Endocannabinoids act as a retrograde messenger to regulate ____.
GABA release
139
Nitric oxide (NO)
gaseous (retrograde) messenger
140
Nitric oxide, is synthesized from _____ by various nitric oxide synthase (NOS) enzymes.
arginine and oxygen
141
NO readily passes through ___.
membranes
142
NO stimulates synthesis of _____.
| second messenger that activates a protein kinase
cGMP (via guanyl cyclase)
