They interfere with axonal propagation by blocking Na channels in the axon's membrane. Blocking Na channels prevents action potential being passed along.
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How does tetrodotoxin work?
It produces paralysis of the diaphragm and death due to respiratory failures
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How can substances influence the release of a transmitter?
Substances may close Ca channels reducing the mount of neurotransmitter released. This can lead to strong muscle contraction.
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How does botulinum toxin work?
It interferes with the release of acetylcholine at exictatory nicotinic synapses, by preventing vesicles from fusing with the membrane.
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How does amphetamine work?
It enters dopamine-releasing neurons either through the membrane or by binding to the dopamine transporter. This forces dopamine out, accelerating the release.
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How do recreational drugs work?
They can have an effect on dopaminergic pathways in the brain, some of which lead to 'pleasure', 'motivation' or 'reward' centres of the brain.
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How does curare work?
It occupies acetylcholine receptors in excitatory synapses, blocking them and causing paralysis.
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How does heroin work?
It imitates the behaviour of a neurotransmitter, thus increasing its effect. Both heroin and marijuana cause greater dopamine release in dopaminergic pathways, which may cause addiction.
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How does the reuptake of neurotransmitters occur?
With help from specialised proteins (transporters).
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How does cocaine work?
It blocks the transporter of noradrenaline and dopamine, interfering with their reuptake and boosting their effect.
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What does tobacco do?
It contains nicotine, which stimulates nicotinic receptors. It gives a short-lived generalised excitatory effect, e.g. increasing blood adrenaline levels.
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How does alcohol work?
It increases the effectiveness of inhibitory synapses, leading to a feeling of relaxation. It indirectly stimulates dopamine release, causing euphoria in the first stage after comsumption.
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What are the effects of alcohol in moderate amounts?
It increases the release of endorphines.
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What are the effect of alcohol in high doses?
The binding of alcohol to GABA channels leads to powerful inhibition and sedation. This can cause brain cell death.
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Does chocolate affect mood?
No, despite containing anandamide and phenylethylamine, these are not present in large enough quantities to cause a substantial effect.
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How does coffee work?
Caffeine competes with adenosine for its receptors, thus reducing its inhibitory effect. It also inhibits the enzyme that breaks down cAMP, increasing glucose metabolism in the cell.
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What is the biological aspect of anxiety disorders?
Characterised by GABA-ergic transmission deficits.
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How do benzodiazepines treat anxiety disorders?
They are non-competitive GABA agonists.
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What is the biological aspect of depression?
Associated with reduced MAO transmission.
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How do monoamine oxidase inhibitors (MAOI) treat depression?
Interfere with MAO, an enzyme that breaks down serotonin, dopamine and noradrenaline.
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How do tricyclics treat depression?
Inhibit the transporter of serotonin, dopamine and noradrenaline.
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How do SSRIs treat depression?
Inhibit the transporter of serotonin, without affecting the other MAOs.
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What is the biological aspect of schizophrenia?
Associated with a surplus of dopamine, which causes paranoia and hallucinations.
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How do neuroleptics treat schizophrenia?
Block the transmission of dopamine by binding to dopamine receptors without opening ion channels.
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Other cards in this set
Card 2
Front
How does tetrodotoxin work?
Back
It produces paralysis of the diaphragm and death due to respiratory failures
Card 3
Front
How can substances influence the release of a transmitter?
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