Lecture 21 - Psychopharmacology Flashcards
What is the sequence of events that happens at the synapse after an action potential reaches the axon terminal?
The action potential causes neurotransmitter vesicles to move towards the membrane, fuse with it, and release the neurotransmitter into the synaptic cleft. The neurotransmitter binds to receptors on the postsynaptic neuron, opening channels and creating a Post-Synaptic Potential (PSP).
How do drugs interfere with synaptic transmission?
Drugs can affect various stages of synaptic transmission, such as axonal propagation (e.g., blocking sodium channels), neurotransmitter release, receptor interactions, and neurotransmitter inactivation/recycling.
What effect does tetrodotoxin (TTX) have on synaptic transmission?
TTX blocks sodium channels in the axon’s membrane, preventing action potential propagation, which can lead to paralysis and respiratory failure.
How does the toxin tetanospasmin interfere with neurotransmitter release?
Tetanospasmin prevents the release of GABA by interfering with the vesicle fusion process, causing excessive excitation and muscle spasms (tetanus).
What effect does botulinum toxin have on synaptic transmission?
Botulinum toxin blocks the release of acetylcholine at nicotinic synapses, which leads to muscle paralysis (used in Botox).
How does amphetamine affect synaptic transmission?
Amphetamine increases the release of dopamine from vesicles by entering the dopamine neuron and interacting with the dopamine transporter, which causes an increase in dopamine in the synapse.
What is the difference between agonists and antagonists in terms of receptor interaction?
Agonists bind to receptors and mimic the effect of the neurotransmitter, enhancing its effect, while antagonists bind to receptors but block the neurotransmitter from acting.
How does curare affect synaptic transmission?
Curare acts as an antagonist by binding to acetylcholine receptors in nicotinic synapses, preventing acetylcholine from binding, leading to paralysis.
What effect does nicotine have on synaptic transmission?
Nicotine acts as an agonist at acetylcholine’s nicotinic receptors, leading to increased excitatory effects such as increased adrenaline release.
How does THC affect neurotransmitter transmission in the brain?
THC acts as an agonist for anandamide, binding to cannabinoid receptors and influencing emotion, pain, appetite, and memory.
How does caffeine work in the brain?
Caffeine blocks adenosine receptors (antagonist), reducing adenosine’s inhibitory effect, and stimulates catecholamine release, increasing alertness.
What is the effect of alcohol on neurotransmitter transmission?
Alcohol acts as a GABA agonist, increasing inhibitory effects, and indirectly stimulates dopamine and endorphin release, leading to relaxation and euphoria at lower doses.
How do benzodiazepines (e.g., Valium) help treat anxiety?
Benzodiazepines are GABA agonists that bind to different sites on GABA receptors, enhancing GABA’s inhibitory effects and reducing anxiety.
How do tricyclic antidepressants (TCAs) work to treat depression?
TCAs inhibit the reuptake of serotonin, dopamine, and noradrenaline, increasing their levels in the synapse and alleviating symptoms of depression.
What is the role of MAO inhibitors in treating depression?
MAO inhibitors block the enzyme monoamine oxidase, which breaks down serotonin, dopamine, and noradrenaline, thus increasing their levels in the brain
What effect does cocaine have on neurotransmitter reuptake?
Cocaine blocks the reuptake transporters for dopamine and noradrenaline, boosting their levels and prolonging their effects in the synapse.
How does methamphetamine increase neurotransmitter transmission?
Methamphetamine reduces reuptake and also promotes the release of dopamine, serotonin, and noradrenaline, boosting their levels in the synapse.
What is the impact of high doses of cocaine and amphetamines on the brain?
High doses can increase dopamine transmission to such an extent that they induce symptoms similar to schizophrenia, such as paranoia and hallucinations.
What is the relationship between dopamine and schizophrenia?
Schizophrenia is associated with an overactive dopamine system, leading to symptoms like paranoia and hallucinations. Neuroleptic drugs act as dopamine antagonists to reduce these symptoms.
What are selective serotonin reuptake inhibitors (SSRIs) used to treat?
SSRIs, like Prozac and Citalopram, are used to treat depression by inhibiting the reuptake of serotonin, increasing its levels in the synapse without affecting other neurotransmitters.
