CNS pharmacology - Anxiolytics and Antiepileptics

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  • Created by: Jess
  • Created on: 15-05-14 12:44
What is the blood brain barrier and why is it important in pharmacology?
It is formed by tight junctions between capillaries. It provides a physical barrier to stop systemically acting drugs from reaching the brain.
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At what points can drugs affect neurotransmission or neuronal function?
Neurotransmitter synthesis, vesicular uptake and storage, neurotransmitter release, neurotransmitter removal and breakdown, ion channels (affect excitability and transmission).
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Outline the G alpha q pathway.
G alpha q subunit activates phospholipase C, cleaves PIP2 to form IP3 and DAG, releases Ca from the sarcoplasmic reticulum and activates protein kinase C.
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What are ionotropic receptors?
Ion channels. They can be ligand gated or voltage gated.
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Outline removal mechanisms uptake 1 and 2 of NA and dopamine.
Uptake 1 - uptake into the synapse, some broken down by MAO and some repackaged into vesicles. Uptake 2 - taken up by glial cells, broken down by COMT.
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What are the main molecular targets for drug action in the CNS?
Enzymes, Transport proteins, Ion channels and Receptors (Ionotropic and GPCR)
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What is anxiety?
Fear response used to prepare te body for defence is instigated in the absence of external cues.
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What are anxiolytics?
Drugs to treat anxiety.
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What are the most common anxiolytics?
Benzodiazepines.
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What receptor do benzodiazepines act at?
GABAa ionotropic receptor. Has an inhibitory effect (hyperpolarises membrane potential).
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How do benzodiazepines work?
Act allosterically to potentiate the effects of GABA. Need both to be bound.
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Give an example of a sustained action and short acting benzodiazepine.
Sustained action - diazepamm, alprazolam, chlordiazepoxide, clobazam. Short acting - lorazepam, oxazepam.
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What is the main problem with benzodiazepines and how is this overcome?
Tolerance and dependences builds up over 1-2 weeks so long term approach uses antidepressants licensed for anxiety.
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What are the main effects of benzodiazepines?
Reduce anxiety and aggression, sedation and induction of sleep, reduction of muscle tone and coordination, anticonvulsant and can produce amnesia.
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What are hypnotics?
Psychoactive drugs used to induce sleep in insomnia and surgical anaesthesia.
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Name some hypnotics.
Benzodiazepines - nitrazepam, flurazepam, temazepam. Non-benzodiazepines - zalepon, zolpidem tartrate, zopiclone.
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What is epilepsy?
Electrical disturbances in the brain leading to seizures - brief, chronically ocurring, rapid onset.
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In order to treat epilepsy, what kind of block of Na channels do we want?
Use-dependent block.
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How does the use dependent block work?
Slow firing - no chance for the drug to accumulate, activity not impaired. Rapid firing - drug accumulation in the channel, activity blocked.
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How can antiepileptics work at the GABAa receptor?
Can act to potentiate the inhibition leading to hyperpolarisation of the cell.
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Name an antiepileptic that works at the GABAa receptor.
Phenobarbital, primidone.
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Name an antiepileptic that works via use-dependent block.
Phenytoin, carbamazepine, lamotrigine.
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Other cards in this set

Card 2

Front

At what points can drugs affect neurotransmission or neuronal function?

Back

Neurotransmitter synthesis, vesicular uptake and storage, neurotransmitter release, neurotransmitter removal and breakdown, ion channels (affect excitability and transmission).

Card 3

Front

Outline the G alpha q pathway.

Back

Preview of the front of card 3

Card 4

Front

What are ionotropic receptors?

Back

Preview of the front of card 4

Card 5

Front

Outline removal mechanisms uptake 1 and 2 of NA and dopamine.

Back

Preview of the front of card 5
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