1a Epilepsy Flashcards
What are focal seizures?
Focal (Partial) Seizures occur when nerve cells in the brain send out sudden, excessive, uncontrolled electrical signals.
What causes the development of seizures?
Imbalance between inhibitory and exitatory input within certain brain regions
Where do most focal seizures arise from?
The temporal lobe
What are the two types of excitatory receptors which are found on Post Synaptic Neurones?
AMPA and NMDA
What is the difference between AMPA and NMDA?
AMPA = Majority of FAST excitatory synapses, permeable to Na+
NMDA = Majority of Slow Excitatory impulses, permeable to both Na+ and Ca2+
What is GABA degraded into?
Succinic semi-aldehyde by GABA Transaminase
What are the four classical drug target sites for epilepsy?
- Receptors
- Enzymes
- Ion channels
- Transport proteins
What are the three common receptors which could be targeted to treat epilepsy?
GABAA receptor, AMPA receptor, NMDA receptor
What enzymes could act as a drug target for epilepsy medication?
GABA transaminase
What ion channels could be targeted to treat epilepsy?
Voltage gated sodium and calcium channel.
What is the drug target of diazepam?
GABA A receptor - alpha subunit
Where is the drug target for diazepam located?
Post-Synaptic neurones in the temporal lobe
How does Diazepam help to treat epilepsy?
Diazepam binds and increases the effectiveness of GABA activation of this receptor (it doesn’t activate the receptor itself). This leads to chloride ion influx (in the presence of GABA) which would hyperpolarize the temporal lobe neurone
How does Lamotrigine work?
Lamotrigine - Blocking the sodium channels reduces neuronal depolaristion which would eventually lead to neurotransmitter release. In this case, glutamate neurotransmission is decreased and there is less excitatory stimulation of the post-synaptic neurone.
Where is the drug target for Lamotrigine?
Glutamatergic neurones in the temporal lobe
How does pregabalin work?
Pregabalin - Blocking the calcium channels prevents calcium influx into the neurone which is required to promote vesicle exocytosis and neurotransmitter release. In this case, glutamate neurotransmission is decreased and there is less excitatory stimulation of the post-synaptic neurone.
What is the non-typical rug target for Levatiracetam?
Synaptic vesicle protein SV2A.
How does levetiracetam work?
This drug interferes with vesicle fusion and therefore reduces exocytosis of glutamate thus decreasing the excitatory activation of the post-synaptic neurone.
Who should sodium valproate not be used for?
Females of childbearing age / with childbearing potential
What is the problem with sodium valporate?
It is a non-selective drug and therefore there is an increased propensity for a larger number of side effects due to it hitting so many more targets
