Stroke and excitotoxicity second half 1.0 Flashcards

1
Q

What happens if the postsynaptic neuron depolarises?

A

Positive ions flow in

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2
Q

Postsynaptic receptor consequences of an excessive release of glutamate?

A

Activate AMPA and KAINATE receptors (both lead to Na+ going into the postsynaptic neuron (more depolarisation))

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3
Q

What happens to NMDA receptors at higher than -40mV?

A

The magnesium block is removed meaning Na+ can flow through

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4
Q

What does the sodium calcium exchanger do?

A

Protects the neurons from having too much sodium in them by swapping intracellular Na+ for extracellular Ca2+

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5
Q

Why does having excessive Ca2+ in a neuron cause issues?

A

It is a signalling molecule that can cause free radicals to form which damage the membrane and cytoskeleton

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6
Q

Which enzymes does Ca2+ activate?

A

Proteases, lipases, caspaces

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7
Q

What happens as a result of caspase activation?

A

Cell death

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8
Q

What happens if Ca2+ activates too much of its enzymes?

A

The lipid bilayer is digested (lipases), as well as anything made of proteins (proteases)

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9
Q

Long term effect on neurons in the core of a stroke?

A

They never repoalrise

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10
Q

What happens to the neurons in the penumbra of a stroke?

A

They can repolarise

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11
Q

What is difficult about repolarising a penumbra neuron?

A

The ATPase NaK pump has to work very hard to restore the concentrations of the ions to the correct level for a -70mV membrane potential, and this uses a lot of energy

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12
Q

Which treatment is only for thrombotic ischaemic strokes?

A

Tissue plasminogen activator (tPA)

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13
Q

What does tPA do?

A

Breaks down blood clots

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14
Q

Treatment for hemorrhagic stroke?

A

Surgery to fix the ruptured blood vessel

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15
Q

What are targets for neuroprotective agents for stroke treatment?

A

AMPA/NMDA receptor blockers, Na+/Ca2+ blockers, enzyme inhibitors

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16
Q

How could neuronal cells be recovered after a stroke?

A

Stem cells

17
Q

What are some things that prevent people from having a stroke again?

A

Antihypertensives

18
Q

Why are antihypertensives used to prevent stroke?

A

Reduce high blood pressure

19
Q

What lifestyle choices can increase risk of stroke?

A

Obesity, lack of exercise, smoking, alcohol

20
Q

For which type of stroke are blood thinners prescribed?

21
Q

What is a transient ischaemic attack?

A

Short lived neurological signs similar to those from a stroke

22
Q

What do the long term stroke symptoms depend on?

A

The brain region affected

23
Q

Symptoms if motor cortex is affected?

A

Skeletal muscle movement affected

24
Q

Symptoms if wernicke’s area of brain is affected?

A

Difficulty understanding language/listening

25
Symptoms if Brocas area of brain is affected?
speech and writing
26
Symptoms if right motor cortex is comprimised?
Left half of body is affected
27
What random molecule can cause exitoxicity?
Domoic acid
28
Why can domoic acid cause excitotoxicity?
It is a glutamate receptor agonist
29
Where is domoic acid found?
Amnesic shellfish
30
What produces domoic acid?
Algae
31
Which glutamate agonists can cause excitotoxicity?
Domoic acid, oxalydiaminopropionic acid, beta-Methylamino-L-alanine
32
Which foods can cause excitotoxicity?
Shellfish, grass pea, cycad seeds