Lecture 7: Anticonvulsants Flashcards
- What is a PARTIAL SEIZURE?
- Starts FOCALLY in a CORTICAL SITE and May Spread
Simple Partial?
Jerking, lasts about 20 seconds w/preservation of consciousness
Complex Partial
Impairment of Consciousness < 2 min. Usually start in Temporal Lobe
Partial w/Secondary Generalized Tonic-Clonic
Starts as Partial seizure then turns into Tonic Clonic: Loss of Consciousness, muscle contractions alternating w/Relaxation
What is Generalized Seizures?
Involve both hemispheres from the outset
Tonic-Clonic (Grand Mal)
Lose consciousness, muscle contractions, generalized
Absence (petit mal)
Staring, cease activity; usually less than 30 seconds
Myoclonic
brief shock-like muscle contraction; may be part of 1 extremity or general
- What produces Seizures?
a. What does this suggest?
- Blocking GABA receptors, or injection of GLUTAMATE RECEPTOR AGONISTS
a. Under-activity of GABAergic neurons, or over-activity of Glutamate transmission
- WHEN can PARTIAL SEIZURES TEND to DEVELOP after HEAD INJURY or STROKE?
- Usually YEARS AFTER
- What is a HYPEREXCITABLE STATE called?
a. What inhibits seizures in this model?
KINDLING…induced in animals via low intensity electrical stimulation of the AMYGDALA or other LIMBIC STRUCTURES
a. Inhibiting NMDA Receptors
Drugs used for Absence Seizures are used to do what?
Block a Voltage Gated Ca2+ channel (T CURRENT)
What 4 drugs act by Blocking Na+ channels, prolonging closure and Inhibiting Glutamate Activity? (PCLV)
PHENYTOIN, CARBAMAZEPINE, LAMOTRIGINE, and VALPROIC ACID
Blockage of Thalamic Low Threshold Calcium Current. (T-current): What 2 drugs work to block this channel?
ETHOSUXIMIDE and VALPROIC ACID
Enhancement of GABA Activity
- What 2 drugs increase GABA activity, and increase HYPERPOLARIZATION of Neurons by opening Cl- Channels?
BENZODIAZEPINES and PHENOBARBITAL
Drugs used in Partial and Generalized Tonic-Clonic Seizures
- Phenytoin
a. What does it block?
b. Very effective against what 2 types of seizures?
c. NOT EFFECTIVE against what?
- a. High frequency, repetitive firing of neurons by prolonging inactivation of Na+ channel
b. Partial and Generalized Tonic-Clonic
c. Absence