Intro and basics of neurotransmission Flashcards

1
Q

What are the 4 classical neurotransmitters involved in addiction?

A

Dopamine, noradrenalin, serotonin and acetylcholine.

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2
Q

What is the shorthand for dopamine and what substances is it associated with?

A

DA - amphetamines and cocaine.

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3
Q

What is the shorthand for noradrenalin and what substances is it associated with?

A

NA - amphetamines and cocaine.

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4
Q

What is the shorthand for serotonin and what substances is it associated with?

A

5-HT (5-hydrocxytryptamine) - ecstasy (MDMA)

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5
Q

What is the shorthand for acetylcholine and what substances is it associated with?

A

ACh - nicotine.

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6
Q

What are synaptic vesicles?

A

Little capsules in the axon terminal of the pre-synaptic neuron that store neurotransmitters. Can be large or small.

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7
Q

What is an axon terminal?

A

The end bit of an axon.

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8
Q

What is the synaptic cleft?

A

The gap between the pre and post synaptic neuron.

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9
Q

Synapses are surrounded by astrocytic processes. What are astrocytes?

A

Star-shaped glial cells in the brain and spinal cord which release gliotransmitters in a similar way to neurons.

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10
Q

What is a dendritic spine?

A

A small membranous protrusion from a neuron’s dendrite that typically receives input from a single synapse of an axon.

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11
Q

What are mitochondria?

A

The cellular organelles responsible for energy (ATP) production.

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12
Q

What is a neuropeptide?

A

Polypeptide compounds that act as neurotransmitters.

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13
Q

What is a terminal autoreceptor?

A

A receptor located on presynaptic nerve cell membranes which serves as a part of a feedback loop in signal transduction - it’s only sensitive to neurotransmitters released by the presynaptic neuron.

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14
Q

What is a somatodendritic autoreceptor?

A

Chemical synapse autoreceptors - they inhibit neuronal cell firing and 5-HT release onto postsynaptic sites.

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15
Q

By what mechanisms can drugs alter synaptic transmission in the presynaptic neuron, other than directly affecting its release?

A
  1. Can serve as NT precursor.
  2. Can inhibit NT synthesis
  3. Can prevent storage of NT in vesicles.
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16
Q

How can drugs alter NT release (directly) in the presynaptic neuron?

A

Can either stimulate or inhibit release, directly or through stimulating or blocking autoreceptors.

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17
Q

By what mechanisms can drugs alter synaptic transmission in the postsynaptic neuron?

A

Can stimulate/block receptors.

18
Q

By what mechanisms can drugs alter synaptic transmission in the synaptic cleft?

A
  1. Can inhibit NT degradation.

2. Can block re-uptake.

19
Q

What are the three types of synaptic connections between neurons?

A

Axodendritic, axosomatic and axoaxonic.

20
Q

Which of the three synaptic connection types is most common?

A

Axodendritic.

21
Q

Where exactly does the synapse form in an axodendritic connection?

A

Along short spines that are present on some dendrites.

22
Q

How many neurotransmitters does a synaptic vesicle contain?

A

Several thousand molecules.

23
Q

What does ATP stand for?

A

Adenine triphosphate.

24
Q

What is ATP used for in synaptic terminals?

A

Ion pumping and transmitter release.

25
Q

What important role do astrocytes play in addiction?

A

They regulate transmission by amino acid transmitters.

26
Q

What does an axoaxonic synapse permit the presynaptic cell to do?

A

Alter NT release from the postsynaptic cell directly at the terminal - presynaptic inhibition/facilitation of release.

27
Q

What is the connection between a neuron and a muscle called, rather than a synapse?

A

Neuromuscular junction.

28
Q

What 6 criteria are used to identify a chemical as a neurotransmitter?

A
  1. Presynaptic cell should make and contain the substance.
  2. Inactivation mechanism present.
  3. Released from terminal on stimulation.
  4. Receptors on postsynaptic cell.
  5. Direct application should have same effect as stimulating presynaptic neuron.
  6. Antagonist drug should inhibit both substance and presynaptic stimulation.
29
Q

What are the major types of classical nts?

A
  • amino acids
  • monoamines
  • acetylcholine
30
Q

What are the most important amino acid nts?

A

Glutamate, glycine and GABA.

31
Q

Amino acids are ____ to monoamines in the biological pathway.

A

Precursors

32
Q

What are the main monoamine nts?

A

Dopamine, serotonin and noradrenaline.

33
Q

What groups are included in the non-classical nts?

A

Neuropeptides, lipids and gases.

34
Q

How are classical nts synthesised?

A

Enzymatic reactions (can occur anywhere in the cell, but mainly in axon terminals).

35
Q

What are neuromodulators?

A

Substances that don’t act like typical nts - rather than directly affecting the postsynaptic cell, may affect the action of an nt. Can diffuse and act at a distance.

36
Q

What is exocytosis?

A

Fusion of the vesicle membrane with the membrane of the axon terminal at an active zone.

37
Q

What is endocytosis?

A

The retrieval of the vesicle membrane from the terminal membrane.

38
Q

What vesicles are recycled?

A

Small ones containing classical nts.

39
Q

What did Gerra et al (2000) do?

A

Found that MDMA users have impaired 5-HT function - when given fenfluramine, they had a reduced response, even when abstinent.

40
Q

What did Miczek and Mutschler (1996) do?

A

Trained rats to respond to a food or cocaine reward, found that response rate increased for cocaine but not food in socially stressing situations (high levels of glucocorticoids). Therefore psychostimulants are powerful rewards and relapse could be triggered by stress.

41
Q

What are the two main categories of nt receptors?

A

Ionotropic (made of 4-5 subunits, channel for ions) and metabotropic (1 protein subunit, which winds back and forth through the membrane 7 times, activate G-proteins).