Anti-Convulsants Flashcards
what is epilepsy?
the overactivity of the brain with a lack of synchronisation of the wave patterns
how is epilepsy activity and pathology detected ?
pathology can be seen on MRI
activity can be seen on EEG
what are the 2 main categories of seizures in epilepsy?
1) general seizures
2) partial/focal seizures
what are general seizures?
Begin simultaneously in both hemispheres
what are the causes of general seizures?
possible genetic link/disorder.
what are the types of general seizures?
- tonic-clonic seizure
- absence seizure
- atonic
- myoclonic
- status epilepticus
what are partial/focal seizures?
start in a particular area and spread
what are the causes of partial seizures?
may be the result of an injury or insult.
what are the types of partial seizures?
- simple
- complex
- temporal lobe epilepsy
what wave of brain activity is seen in aware- hyperactivity?
gamma
what wave of brain activity is seen in aware-thinking?
beta
what wave of brain activity is seen in aware-relaxed?
alpha
what wave of brain activity use seen in drowsy-meditation?
theta
what wave of brain activity is seen in deep sleep?
delta
what happens to the brain wave activity in seizure?
The wave patterns are irregular or asynchronous due to neuronal OVER-activity.
what are tonic-clonic seizures?
your classic movie seizure
general: loss of consciousness–> muscle stiffness–> jerking–> deep sleep
wake up after
what are absence seizures?
general: brief staring episodes with behavioural arrest; loss of muscle function
what are atonic seizures?
general: sudden muscle stiffness; sudden loss of muscle function
what are myoclonic seizures?
generalised: sudden brief muscle contraction
what is Status epilepticus?
seizure activity for greater than 5 minutes
what is a simple partial seizure?
there is retained awareness/conciousness
what is a complex partial seizure?
there is impaired awareness/conciousness
what is the significant of targetting glutamate-mediated neurotransmission in epileptics?
the aim is to reduce this excitatory neurotransmission in seizures
how does glutamate mediated neurotransmission occur?
- VGSC opens –> membrane depolarisation.
- VGKC opens —> membrane repolarisation (efflux)
- VGCC-mediated Ca2+ influx –> glutamate vesicle exocytosis into the cleft
- Glutamate binds to post-synaptic receptors
– e.g. NMDA, AMPA, Kainate receptors
what enables the glutamate vesicle to be exocytosed after calcium influx occurs?
docking proteins like SV2a
(Synaptic Vesicle Associated) allows vesicle attachment to the presynaptic membrane
therapeutic target
what are the receptors that glutamate can bind to post-synaptically to have an excitatory effect?
NMDA
AMPA
Kainate receptors
what are the targets within the glutamate neuronal system for treating seizure?
- VGSC
- VCKC
- VGCC
- exocytosis of glutamate vesicles
- post synaptic glutamate receptors
what drugs target VGSCs to prevent Na+ influx?
Carbamazine
– VGSC antagonist
Lamotrigine
– VGSC antagonist
Phenytoin
– VGSC antagonist