Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pharm > Lecture 15: Drugs used to Treat Seizure Disorders > Flashcards

Lecture 15: Drugs used to Treat Seizure Disorders Flashcards

(83 cards)

Start Studying
1
Q

What are Seizures?

A

A transient alteration of behavior due to abnormally excessive and synchronous neuronal activity in the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Epilepsy?

A

A disorder of brain function characterized by the periodic and unpredictable occurrence of seizures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does it mean for epilepsy to be symptomatic?

A

Occur due to a known even such as head trauma or cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does it mean for epilepsy to be asymptomatic?

A

Generally due to poorly defined genetic factors but don’t really know the cause of the seizures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Do seizures need to be provoked by something?

A

Seizures can be provoked or unprovoked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

With what synchronicity do neurons usually fire in the brain?

A

They usually fire asynchronously in normal conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the spread of electrical activity maintained by?

A

Changes in membrane potential following depolarization (refractory period) and surround inhibition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is electrical activity insulated in the brain?

A
  • By the refractory period of an action potential

* By surround inhibition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is Surround Inhibition?

A

The physiological mechanism that focuses neuronal activity in the central nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are primary afferents?

A

Neurons that innervate the skin and any surface of our body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens if the receptive field of a neuron is stimulated?

A

It will produce more action potential than those on the periphery of the receptive field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens if the edge of a neuron’s receptive field is stimulated?

A

It will not produce as many action potentials of those that are stimulated in the center of the receptive field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens when a neuron in the receptive field synapses with the interneuron?

A

The interneuron creates action potentials but also activates GABAergic neurons which inhibits the neighboring neurons to quiet their neuronal activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does surround inhibition work?

A

The neuron that is stimulated inhibits action potentials in the surrounding neurons but activating GABAergic neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the three steps in seizures?

A
  • Initiation
  • Propagation
  • Termination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What two events is seizure initiation characterized by?

A
  • High frequency bursts of action potentials

* Hyper synchronization of neuronal population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which receptors does high frequency stimulation recruit?

A

NMDA receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What flows through NMDA receptors?

A

Calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the two main classes of glutamate receptors?

A
  • AMPA receptors

* NMDA receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What receptors drive the excitatory effect of glutamate initially?

A

AMPA receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do AMPA receptors work?

A

Glutamate binds to the AMPA receptor causing it to open and sodium can flow into the cell causing membrane depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why are NMDA receptors usually inactive?

A

Because they have a magnesium block in them that blocks the flow of sodium even when glutamate binds to them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When are NMDA active?

A

When many AMPA receptors are active allow the magnesium block to dissociate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What ions are NMDA receptors permeable to?

A

Calcium and sodium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the sustained neuronal depolarization in seizures driven by?
Calcium influx through NMDA receptors
26
What is the propagation of bursting activity in the brain normally prevented by?
Hyperpolarization and surround inhibition
27
How can the barriers of surround inhibition and hyperpolarization be overcame?
* Increasing extracellular potassium * Accumulation of calcium * Activation of the NMDA receptor
28
What does increasing extracellular potassium do?
Blunts the hyperpolarizing outward potassium currents
29
What does increased accumulation of calcium do?
In the presynaptic terminals leads to enhanced neurotransmitter release
30
What does activation of the NMDA receptor do?
Causes more calcium influx and neuronal activation
31
What happens if the barriers of hyperpolarization and surround inhibition are overacame?
Then seizure activity is propagated through the brain
32
How do seizures generally resolve?
Spontaneously
33
The do the mechanisms that terminate a seizure involve?
* loss of ionic gradients * depletion of ATP * depletion of neurotransmitters (e.g. glutamate) * activation of inhibitory circuits (GABA)
34
What is Status Epilepticus?
A seizure lasting longer than 5 minutes of having more than 1 seizure within a 5 minute period. This is life threatening
35
What is a postictal period?
The 5-30 minutes after a seizure that is characterized by drowsiness, confusion, depression/anxiety and sometime psychosis
36
Why does the Postictal period occur?
Because of abnormal electrical activity in the brain resetting
37
What do the different classification of seizures depend?
* Where in the brain they initiate | * How widely they propagate
38
What are the three types of seizure classes?
* Focal seizures * Generalized seizures * Nonconvulsive (absence) seizures
39
What do the diverse manifestations of Focal seizures depend on?
Where in the brain it originates
40
What is the difference between simple and complex Focal seizures?
Simple - Retain consciousness | Complex - Loss of consciousness
41
What is jerking activity like in Focal seizures?
Jerking activity may start in a specific muscle group and spread to surround muscle groups
42
What are Automatisms that are seen in Focal seizures?
Unusual activities that are not consciously created like smacking the lips
43
What is a Focal Seizure?
Abnormal electrical activity that occurs in a very precise part of the brain and doesn't spread very far
44
What does the different behavioral manifestation of a Focal seizure indicate?
Where in the brain the seizure is occuring
45
What is Jacksonian March?
In focal seizures where the jerking activity may start in a certain muscle and spread to surrounding muscle groups
46
What are Generalized seizures?
Abnormal electrical activity that starts in one precise part of the brain but then migrates or propagates throughout the entire brain
47
What are the two types of Generalized Seizures?
Tonic-clonic and Myoclonic
48
How do generalized seizures effect conciousness?
They generally involve loss of consciousness and occur without warning
49
What are Tonic-clonic generalized seizures?
Sustained contractions (tonic) of muscles throughout the body followed by periods of alternating muscle contraction and relaxation (clonic)
50
What are Myoclonic generalized seizures?
A brief (~1s) shock like contraction of muscles that may be localized or generalized
51
What are the two types of Non-convulsive seizures?
Absence and atonic seizures
52
What are Absence seizures characterized by?
An abrupt onset of impaired consciousness
53
What are Atonic seizures characterized by?
A sudden loss of muscle strength
54
How is consciousness affected in atonic seizures?
Usually consciousness is maintained but a person may fall down
55
What are anti seizure drugs used for?
To prevent the occurrence of seizures in people with epilepsy
56
When are anti seizure drugs used to treat people without epilepsy?
When people have acute illnesses such as meningitis that may cause seizures
57
Can epilepsy be cured or prevented?
No
58
What do anti seizure drugs generally do?
* Enhance inhibitory (GABAergic) neurotransmission | * Diminish excitatory (glutamatergic) neurotransmission
59
How do antiseizure drugs enhance GABA or decrease glutamate?
* blocking ion conductance (Na, Ca and K) * blocking neurotransmitter release * inhibiting/activation the postsynaptic membrane
60
How do seizure medication effect GABA?
The bind to the GABAa receptor on the postsynaptic membrane
61
What kind of receptor is the GABAa receptor?
A ligand gated ion channel that allows chloride to flow into the cell hyperpolarize the membrane
62
What are the two antiseizure drugs that target the GABA system?
* Benzodiazepines | * Barbiturates
63
What do Benzodiazepines and Barbiturates do?
They enhance the activity of GABA by binding to an allosteric site
64
What is the difference between Benzos and Barbiturates at the GABA receptor?
Benzos have no effect on the GABA receptor in the absence of GABA while barbiturates can act as GABA agonists at higher concentrations
65
What kind of ligands are Benzos and barbiturates to GABAa receptors?
They are positive allosteric modulators
66
What is the difference in frequency of the GABAa channels that Benzodiazepines and Barbiturates act?
* Benzos increase frequency at which GABAa receptor opens | * Barbiturates increase the duration at which the GABAa receptor is open
67
What is the difference between Benzodiazepines and Barbiturates affect efficacy and potency?
Benzodiazepines increase Potency | Barbiturates increase Efficacy
68
Why is the risk of overdose higher for barbiturates?
Because it directly gates the GABA receptor
69
When is there an added risk when taking Benzodiazepines or Barbiturates?
When taken with other CNS depressants like alcohol or opioids
70
What does Vigabatrin do?
Inhibits GABA aminotransaminase (GABA-T) that is involved in the degradation of GABA
71
What does Tiagabine do?
Inhibits the GABA transporter (GAT-1 located in neurons and glia) which prolongs the action of the neurotransmitter
72
What does Carbamazepine do?
Blocks voltage gated sodium channels
73
How does Carbamazepine block voltage gated sodium channels?
By causing a conformational change of the inactivation gate after entering the cell
74
What is the Phobicity of Carbamazepine?
It is lipophilic so it enters the the cell
75
What is the rate of sodium channel blockers like carbamazepine dependant on?
The frequency of cell firing. A cell that fires more is blocked more
76
What does Gabapentin look like?
A GABA molecule covalently bound to a lipophilic cyclohexane ring
77
What does Gabapentin do?
Inhibits voltage gated calcium channels by binding to the alpha2delta subunit preventing glutamate neurotransmitter release
78
What kind of drug a Perampanel?
It is a non-competitive antagonist at the AMPA receptor
79
What does Perampanel do?
It blocks AMPA receptors so it blocks action potentials
80
What are the side effects of Perampanel?
* Behavioral changes * Mood disorders * Suicidal/homicidal ideation
81
Why is consideration of pharmacokinetic properties important for seizure medications?
Because the drugs are taken for long periods the need to prevent toxicity
82
What is the extraction ratio of anti-seizure drugs?
They have a low extraction ratio (can be long acting)
83
Why are antiseizure drugs very lipophilic?
Because they need to cross the BBB

Pharm (31 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions