epilepsy science Flashcards
pathophysiology of epilepsy
arises as a result of inhibitor (GABA) and excitatory (glutamate) activity
neurons in focal area show sudden depolarisations
hyperexcitability in regions surrounding the focal area
what is the pathophysiology of absent seizures
oscillatory feedback between cortical and thalamic neurons
involves activity of t-type voltage gated calcium channels
what are the 4 main MOA for antiepileptic drugs
enhanced GABA transmission
acting at GABAergic synapses
inhibition of GABA reuptake
inhibition of Na and Ca channels
what is the aetiology of epilepsy
mutations in
- ion channels
- GPCRs
- enzymes
- neurotransmitters
how do drugs that enhance GABA transmission help epilepsy
- inhibit pre-synaptic degradation
- act at post synaptic receptors to enhance signalling
- act at pre-synaptic terminal and non-neuronal cells to keep GABA in synapse
which anti-epileptic drugs enhance GABA transmission
benzodiazepines and barbiturates act at the modulatory site
gabapentin is a GABAa agonist but also blocks P/Q calcium channels
how do anti-epileptic drugs act at the GABAergic synapse
vigabatrin is a GABA transaminase inhibitor - increases the amount of GABA that can be released
how do anti-epileptic drugs inhibit GABA uptake
tiagabine is a GAT1 inhibitor in neurons and non-neuronal cells to increase the amount of GABA in the synapse
how do anti-epileptic drugs inhibit Na+ channels
inhibit channels to stop action potentials - exhibit use dependency
which anti-epileptic drugs inhibit Na+ channels
valproate
phenytoin
carbamazepine
lamotrigine
rufinamide
lacosamide
how do anti-epileptic drugs inhibit Ca2 channels
T type ca2+ channels involved in absent seizures
which anti-epileptic drugs inhibit Ca2 channels
ethosuximide
valproate
clonazepam
how does levetiracetam work
Binds to synaptic vesicle protein SV2A to modulate neurotransmitter release
how does phenobarbital work
inhibits glutamate receptors and enhances GABA receptors while blocking Na channels
how does topiramate work
blocks AMPAR, Na and Ca channels to enhance the effect of GABA
