Epilepsy

Question 1

What causes convulsions?

Answer 1

Imbalance between excitary and inhibitory neurotransmission

Question 2

How is epilepsy characterised?

Answer 2

Unprovoked seizures
High frequency discharge by a group of neurons
Partial or generalised spread
Hyperexcitability of the CNS

Question 3

What is used to diagnose epilepsy?

Answer 3

EEG

Question 4

Where does loss of consciousness take place in the brain due to convulsions?

Answer 4

Reticular formation

Question 5

What can cause epilepsy?

Answer 5

Head injuries
Lesions (bleeding from age)
Tumour
Infection
Genetics
Na/K channels
GABAa
Nicotinic receptors

Question 6

Where do convulsions begin in the brain?

Answer 6

Motor cortex

Question 7

Where does autonomic discharge take place in the brain?

Answer 7

Hypothalamus

Question 8

What triggers are there for epilepsy?

Answer 8

Altered blood glucose/pH
Stress
Fatigue
Flashing lights/noise

Question 9

What gain of function mutations are associated with epilepsy?

Answer 9

Voltage gated sodium channels

Question 10

With partial seizures, where is brain activity localised?

Answer 10

One hemisphere of the brain

Question 11

What are the two types of generalised seizures?

Answer 11

Clonic tonic (grand mal)
Absence seizures (petit mal)

Question 12

What happens in focal seizures?

Answer 12

Brain activity is localised to one area an causes a change in sensation, such as strange taste or smell

Question 13

What chemical models have been used to test epilepsy drugs on animals?

Answer 13

Penicillin crystals put directly onto the brain to inhibit GABAa activity
PTZ
Kainate

Question 14

What is the kindling animal model for epilepsy?

Answer 14

Repeated low level electrical stimulation on genetically modified animals

Question 15

How do benzodiazepines and barbiturates act as anti-epileptics?

Answer 15

Increase GABAa transmission

Question 16

How does GABApentin work?

Answer 16

binds to α2/β subunit of voltage gated calcium channels, decreasing action potentials

Question 17

How does tiagabine act as an anti-epileptic?

Answer 17

Inhibits GABA uptake

Question 18

How do vigabatrin and valproate act as anti-epileptics?

Answer 18

Act as GABA transaminases

Question 19

What do GABA transaminases do?

Answer 19

Convert GABA to succinate semialdehyde

Question 20

What does sodium valproate do?

Answer 20

Inhibits Na+ and GABAa channels
Inhibits HDAC, responsible for histone binding which favours DNA transcription
Not sedative

Question 21

What problems can Na+ channel inhibitors cause?

Answer 21

Complex pharmacodynamics
Vertigo
Ataxia
Headaches

Question 22

What problems are associated with lamotrigine (Na+ channel blocker)?

Answer 22

Nausea
Dizziness
Ataxia
Rashes

Question 23

What are 3-Ca2+ channel blockers used for?

Answer 23

Absence seizures

Question 24

Give an example of a 3-Ca2+ channel blocker

Answer 24

Ethosuximide

Question 25

What is the mechanism of 4-Ca2+ channel blockers

Answer 25

Bind to the a subunit of the Ca2+ channel which is used for inserting into the plasma membrane
Binds to a protein on synaptic vesicles which controls glutamate levels

Question 26

Give 2 examples of 4-Ca2+ channel blockers

Answer 26

GABApentin
Pregabalin