Stroke and excitotoxicity second half 1.0

Question 1

What happens if the postsynaptic neuron depolarises?

Answer 1

Positive ions flow in

Question 2

Postsynaptic receptor consequences of an excessive release of glutamate?

Answer 2

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

Question 3

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

Answer 3

The magnesium block is removed meaning Na+ can flow through

Question 4

What does the sodium calcium exchanger do?

Answer 4

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

Question 5

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

Answer 5

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

Question 6

Which enzymes does Ca2+ activate?

Answer 6

Proteases, lipases, caspaces

Question 7

What happens as a result of caspase activation?

Answer 7

Cell death

Question 8

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

Answer 8

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

Question 9

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

Answer 9

They never repoalrise

Question 10

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

Answer 10

They can repolarise

Question 11

What is difficult about repolarising a penumbra neuron?

Answer 11

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

Question 12

Which treatment is only for thrombotic ischaemic strokes?

Answer 12

Tissue plasminogen activator (tPA)

Question 13

What does tPA do?

Answer 13

Breaks down blood clots

Question 14

Treatment for hemorrhagic stroke?

Answer 14

Surgery to fix the ruptured blood vessel

Question 15

What are targets for neuroprotective agents for stroke treatment?

Answer 15

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

Question 16

How could neuronal cells be recovered after a stroke?

Answer 16

Stem cells

Question 17

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

Answer 17

Antihypertensives

Question 18

Why are antihypertensives used to prevent stroke?

Answer 18

Reduce high blood pressure

Question 19

What lifestyle choices can increase risk of stroke?

Answer 19

Obesity, lack of exercise, smoking, alcohol

Question 20

For which type of stroke are blood thinners prescribed?

Answer 20

Ischaemic

Question 21

What is a transient ischaemic attack?

Answer 21

Short lived neurological signs similar to those from a stroke

Question 22

What do the long term stroke symptoms depend on?

Answer 22

The brain region affected

Question 23

Symptoms if motor cortex is affected?

Answer 23

Skeletal muscle movement affected

Question 24

Symptoms if wernicke’s area of brain is affected?

Answer 24

Difficulty understanding language/listening

Question 25

Symptoms if Brocas area of brain is affected?

Answer 25

speech and writing

Question 26

Symptoms if right motor cortex is comprimised?

Answer 26

Left half of body is affected

Question 27

What random molecule can cause exitoxicity?

Answer 27

Domoic acid

Question 28

Why can domoic acid cause excitotoxicity?

Answer 28

It is a glutamate receptor agonist

Question 29

Where is domoic acid found?

Answer 29

Amnesic shellfish

Question 30

What produces domoic acid?

Answer 30

Algae

Question 31

Which glutamate agonists can cause excitotoxicity?

Answer 31

Domoic acid, oxalydiaminopropionic acid, beta-Methylamino-L-alanine

Question 32

Which foods can cause excitotoxicity?

Answer 32

Shellfish, grass pea, cycad seeds