G Flashcards

1
Q

For a molecule to be regarded as an NT, what must there be regarding it in the presynaptic neuron?

A

It itself must be present, as well as the mechanisms for its synthesis (enzymes etc)

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2
Q

For a molecule to be regarded as an NT, what must there be regarding it on the postsynaptic neuron?

A

Receptors to which the NT can bind

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3
Q

What are the three criteria for defining a NT?

A

Present in the presynaptic neuron
Capable of being released
Postsynaptic receptors to which it can bind

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4
Q

What kind of NT is glutamate?

A

An AA transmitter

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5
Q

What is the main excitatory NT in the CNS?

A

Glutamate

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6
Q

What is glutamate synthesised from?

A

Glutamine

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7
Q

What is glutamate reuptaken by?

A

Excitatory AA transporters

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8
Q

What other molecule can activate glutamate receptors?

A

Aspartate

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9
Q

What is excitotoxicity?

A

Too much signalling that leads to cell death

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10
Q

Where is glutamine first found in the glutamate synthesis pathway?

A

In glial cells

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11
Q

What first happens to glutamine in the glutamate synthesis pathway?

A

It is transported out of glial cells via glutamine transporters

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12
Q

Which enzyme converts glutamine to glutamate in the glutamate synthesis pathway?

A

Glutaminase

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13
Q

Where is glutaminase found?

A

In nerve cells

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14
Q

Which molecule helps glutamate be taken up into synaptic vesicles?

A

Vesicular glutamate transporters

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15
Q

Where are EAATs found?

A

Presynaptic neurons and glial cells

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16
Q

What are the two main classes of NT receptors?

A

Ionotropic and metabotropoic

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17
Q

What are ionitropic receptors?

A

Ligand gated ion channels

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18
Q

WHat are metabotropic receptors?

A

G protein coupled receptors

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19
Q

What are the three classes of ionotropic receptor?

A

NMDA, AMPA, KAINATE

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20
Q

What are the three classes of metabotropic receptor?

A

Group I, Group II, Group III

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21
Q

What kind of ion channel does NMDA, AMPA, KAINATE all form?

A

tetrameric ligand gated ion channels

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22
Q

Which subunit must an NMDA receptor have?

A

GluN1

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23
Q

What separates the different groups of metabotropic receptors?

A

The second messengers they couple to

24
Q

Which second messenger does Group 1 couple to?

A

G alpha Q

25
Q

Which second messenger does Group 2 couple to?

A

G alpha i o

26
Q

Which second messenger does group III couple to?

A

G alpha i o

27
Q

How does glutamate bind so many receptors?

A

Not a rigid molecule, can adopt different conformations

28
Q

What is present in the middle of the ionotropic subunits?

A

An ion channel pore

29
Q

Which subunits of an ionotropic receptor are transmembrane?

A

1, 3, 4

30
Q

Which subunits of an ionotropic receptor are not transmembrane?

A

2

30
Q

Which subunit segment is facing inwards to the ion channel in a ionotropic glutamate receptor?

A

2

31
Q

Which receptor can be homomeric?

A

AMPA

32
Q

What is an AMPA receptor permeable to?

A

K+ and Na+

33
Q

What is the direction of K+ through an AMPA receptor?

A

Leaving the cell

34
Q

What is the direction of Na+ through an AMPA receptor?

A

Entering the cell

35
Q

Agonists of AMPA receptor?

A

glutamate, AMPA, KA

36
Q

Antagonists of AMPA receptor?

A

NBQX (competitive), GYKI (non-competive)

36
Q

What ions are NMDA receptors permeable to?

A

Ca2+, Na+, K+

37
Q

What is the direction of K+ through an NMDA receptor?

A

leaving the cell

38
Q

What is the direction of Ca2+ and Na+ through an NMDA receptor?

A

Entering the cell

39
Q

What kind of gated is an NMDA receptor?

A

voltage and ligand

39
Q

Which receptor requires a co-agonist?

A

NMDA

40
Q

What co-agonists do an NMDA receptor require?

A

Glycine or serine

41
Q

Why can a fast and slow time course be observed on the postsynaptic EPSP?

A

AMPA are fast, NMDA are slow and glutamate binds both

42
Q

Meaning of a dual gating receptor?

A

both ligand and voltage sensitive

43
Q

Which molecule blocks a NMDA receptor at resting potentian?

A

Mg2+

44
Q

What does depolarisation do to the NMDA receptor?

A

Relieves the MG2+ block from the ion pore

45
Q

Which ions are NMDA receptors highly permeable to?

A

Ca2+

46
Q

WHat speed of excitation are metabotropic receptors involved in?

A

slow

47
Q

Which molecules are NMDA receptor ion channel blockers?

A

Ketamine and memantine

48
Q

What happens when glutamate binds to an mGluR presynaptically?

A

G beta gamma subunits dissociate and close a calcium ion channel (stops Ca2+ from entering), preventing release of an NT

49
Q

What happens when glutamate binds to an mGluR postsynaptically?

A

G beta gamma subunits dissociate and close a potassium ion channel (stops K+ from leaving), leads to a slow depolarisation

50
Q

What can mGluR affect in terms of calcium?

A

Its intracellular release

51
Q

What do group 1 mGluRs do?

A

produce slow depolarisation and release Ca2+ from intracellular stores

52
Q

What do group 2/3 mGluRs do?

A

Inhibit glutamate and other transmitters reease