Lecture 15: chemical brain Flashcards
1
Q
wat is a chemical signal?
A
neurotransmitter
2
Q
what are the two types of signalling with neurotransmitters?
A
Electrical
Effects on cell metabolism
3
Q
what happens with a action potential at the synapse?
A
- action potential reaches pre synaptic terminal
- calcium channels open
- vesicles fuse with membrane and undergo exocytosis
- neurotransmitters are released into the synaptic cleft
- neurotransmitters bind to specific receptors on the postsynaptic neurone
4
Q
what stem criteria for defining a neurotransmitter?
A
- substance present in presynaptic cell
- substance must be released upon the arrival of an action potential
- Specific receptors must be present on the postsynaptic cell
- Inactivation of the substance must occur
- substance is applied to the postsynaptic cell directly, it should have the same effect
5
Q
glutamate is ______ and GABA is ______.
A
- excitatory
2. inhibitory
6
Q
Name 3 catecholamines?
A
Dopamine
Noradrenaline
Adrenaline
7
Q
monoamines include?
A
Catecholamines Indoleamines
8
Q
name a Indoleamine?
A
Serotonin
9
Q
ionotropic receptors are also called what?
A
ligand-gated ion channels
10
Q
EPSP is ?
A
Excitatory postsynaptic potential
11
Q
IPSP is?
A
inhibitory postsynaptic potential
12
Q
Ionotropic receptors are _____ acting.
A
fast
13
Q
what are glutamate inotropic
receptors?
A
NMDA, AMPA and kianate
14
Q
what are glutamate matabotropic receptors?
A
mGluR group I
mGluR group II
mGluR group III
15
Q
glutamate causes ___ to come in causing ______.
A
- sodium
2. depolarisation
16
Q
glutamate is ______, it can be taken out my a neighbouring ____ cell.
A
- recycled
2. glia
17
Q
what would happen if glutamate ermine din the synaptic cleft?
A
there could be exitotoxicity
18
Q
where is GABA synthesised?
A
at the axon terminal by glutamate
19
Q
what are GABA inotropic
receptors?
A
GABA(A)
20
Q
what are GABA Metabotropic receptors?
A
GABA(B)
21
Q
what does GABA allow to enter?
A
negatively charged chloride ions (hyper polarises the cell)
22
Q
GABA causes a _____ in membrane potential because the cell is ________.
A
- decrease
2. hyperpolarised
23
Q
is GABA inhibitory?
A
yes
24
Q
Glutamate and GABA are extremely important in the ______ ______.
A
Basal ganglia
25
to produce acetylcholine acetate has to become what?
Acetyl coenzyme A
26
where is Acetyl coenzyme A released from?
mitochondria
27
Acetyl coenzyme A combines with _____ to form acetylcholine.
1.choline
28
what does acetylcholine bind too?
Binds to specific ACh receptors on the postsynaptic neuron
29
what is acetylcholine inotropic receptor?
Nicotinic - fast acting
30
what also binds to the Nicotinic receptor?
nicotine
31
what is acetylcholine metabotropic receptor?
Muscarinic – slow acting
32
acetylcholine is broken down by?
acetylcholinesterase
33
what happens when acetylcholine is broken down?
choline is transported back.
34
Glutamate and GABA are very ____ _____ throughout the brain.
1.wide spread
35
is acetylcholine more localised then glutamate and GABA?
yes
36
acetylcholine is important for what?
muscle movement and voluntary movement
37
acetylcholine is found in which parts of the brain?
cortex and hippocampus,
| striatum
38
in what form is acetylcholine found in the striatum?
form of interneurones
39
acetylcholine can be involved in ____ and _______.
1. arousal
| 2. attention
40
acetylcholine in the heart slows down what?
herat rate
41
acetylcholine in muscles ______ muscle movement.
increases
42
what does a agonist do?
mimics the action of the neurotransmitter
43
what does a Antagonist do?
blocks the action of the neurotransmitter
44
Name two agnoists?
Nicotine
| Muscarine
45
Name to Antagonists?
Curare
| Atropine
46
what does Latrotoxin do?
comes from poisonous spiders, increases ACh effects – forms pores in membrane
47
what does Botulinum toxin (BOTOX) do?
decreases ACh effects – prevents vesicle fusion
48
Are Noradrenaline and Norepinepherin exactly the same?
yes
49
what is noradrenaline synthesised from?
dopamine via dopamine beta- hydroxylase
50
Noradrenaline can become?
adrenaline
51
Noradrenaline binds to what?
alpha or beta metabotropic receptors
52
Noradrenaline is ____ acting.
slow
53
whats an example of what Noradrenaline does?
1. binds to beta receptor
2. activates G protein
3. increases effector adenyl cyclase
4. increases cAMP
5. increases protein kinase
6. increases protein phosphorylation
54
Noradrenaline can mainly be found in the?
locus coeruleus
55
locus coeruleus projects noradrenaline to which other parts of the brain?
cortex and hippocampus
56
noradrenaline is involved in ....
1. Attention and memory during cognitive tasks
2. arousal
3. sleep-wake cycle
57
noradrenaline modulates ___ __ ______ via the ______ nervous system
1. fight or flight
| 2. sympathetic
58
where does dopamine reside and where does it project too?
resides in the substantial nigra
| projects to the striatum
59
dopamine pathway is involved in functions such as?
1. reward
2. pleasure,euphoria
3. motor function
4. compulsion
5. preservation
60
serotonin pathway is involved in functions such as?
mood
memory processing
sleep
cognition
61
Nigrostriatal pathway is a critical pathway in the ___ _____.
basal ganglia
62
what neurone does the striatum contain?
medium spiny neurons
63
what type of medium spiny neurons are excited by dopamine?
those expressing dopamine D1 receptors
64
MSNs expressing dopamine D2 receptors are what by dopamine?
inhibited by dopamine
65
what happens when dopamine minds to dopamine D2 receptors ?
1. binds to dopamine D2
2. activates Gi protein
3. decreases effector adenyl cyclase
4. decreases cAMP
5. decreasesprotein kinase
6. decreases protein phosphorylation
66
Parkinson’s Disease is a ______ _______.
1. hypokinetic
| 2. disorder
67
Parkinson's is what kind of condition?
neurodegenerative condition
68
what happens to dopamine during Parkinson’s Disease?
- Dopamine-producing cells in the substantia nigra undergo cell death
- disorder of basal ganglia causing less movement
69
what are symptoms of pakinsons disease?
```
• Bradykinesia
– Slowness of movement
– Shuffling gait
• Akinesia
– Difficulty initiating movements
• Rigidity due to increased muscle tone
• Resting tremor
• Depression
```
70
what are treatments for Parkinson's disease?
- L-DOPA
- Deep brain stimulation
- Anticholinergic drugs
(Not used much nowadays)
- Cell transplantation
71
where is the Ventral tegmental area located?
in the midbrain
72
Ventral tegmental area is known as the _____ leaning centre.
1.reward
73
Dopaminergic cell bodies reside in the ___
VTA
74
Tonic firing of dopamine neurones causes what?
small spikes, not sufficient to evoke response
75
what are the two types of firing in the VTA?
tonic and phasic
76
Phasic firing of dopamine neurones causes what?
large spikes, leading to dopamine being released at presynaptic neurone and receptors being activated.
77
what did Schultz do?
- recorded from the VTA of monkeys
| - trained to link visual cue with reward
78
what is the nucleus accumbens known as?
motivational centre
79
what experiment shows how dopamine is linked to motivation?
Healthy rat would travel more to get more food.
| rats with no dopamine would take the easy route with little food.
80
what does cocaine do (linked to dopamine)?
blocks dopamine transporter
81
why does someone get addicted to cocaine?
nucleus accumbens gets more and more dopamine, become addicted.
82
what are the pleasure peptides in the brain?
Opioids
83
what do opioids bind too?
bind to opioid G-protein coupled receptors
84
Name 4 opioid drugs?
Morphine
Opium
Heroin
Fentanyl
85
Name 4 Endogenous opioids?
ß-Endorphin
Enkephalin
Dynorphin
Nociceptin
86
How is serotonin made?
form Tryptophan
87
where do we get Tryptophan from?
diet
88
which serotonin receptor is inotropic ?
5HT3 is ionotropic
| majority metabotropic
89
serotonin is also known as?
5-HT
90
whats the main region for serotonin?
raphe nuclei
91
serotonin is projected to the?
forebrain
92
serotonin is removed form the synaptic cleft via?
SERT
93
what do SSRI's do?
keep serotonin in the synaptic cleft (used to treat depression)
94
which neuropeptides increase apetite?
Orexigenic neuropeptide:
NPY
AgRP
95
which neuropeptides decrease apetite?
Anorexigenic neuropeptides:
pomC
CART
96
what is leptin involved in?
Leptin is a key hormone involved in the regulation of food uptake and energy expenditure
97
where is leptin synthesised from?
adipose tissue
98
leptin ____ appetite?
decreases
