L12 - Neuropharmacology Flashcards
What does neuropharmacology study?
How chemicals like drugs and neurotransmitters affect neuronal function in the nervous system
What are endogenous chemicals in neuropharmacology?
Neurotransmitters
What are exogenous chemicals in neuropharmacology?
Drugs
What role do calcium channels play in neurotransmitter release?
Calcium influx triggers vesicle fusion with the presynaptic membrane, which releases neurotransmitters into the synaptic cleft.
How are neurotransmitters cleared from the synaptic cleft?
Through reuptake by transporters, enzymatic breakdown or diffusion away from the cleft
What is the synaptic cleft?
Small gap between presynaptic and postsynaptic neurons where neurotransmitter transmission occurs
How do neurotransmitters binding to receptors affect the postsynaptic neuron?
It can cause either excitation (EPSP) or inhibition (IPSP) depending on the receptor type
What is the role of ionotropic receptors?
They directly regulate ion fluxes through ion channels
What happens when acetylcholine binds to a nicotinic receptor?
Sodium channels open, causing depolarisation (Excitatory Postsynaptic Potential - EPSP).
How does GABA binding to GABA-A receptors affect the cell?
Chloride channels open, causing hyperpolarisation (Inhibitory Postsynaptic Potential IPSP)
What is the difference between metabotropic and ionotropic receptors?
Metabotropic receptors regulate intracellular metabolic reactions often through G-protein mediated systems and have slower, longer-lasting effects.
Ionotropic receptors directly regulate ion fluxes through ion channels causing rapid ad short-lasting effects
Give an example of a metabotropic receptor?
Muscarinic acetylcholine receptors
what are 3 examples of ionotropic receptors?
Glutamate receptors, GABA-A receptors, nicotine acetycholine receptors
Name a serotonin receptor that’s ionotropic?
the 5HT-3 receptor
What is a receptor agonists?
A substance that mimics the action of the native neurotransmitter at a receptor
What is a receptor antagonist?
Substances that bind to a receptor but don’t activate it, blocking neurotransmitter binding
What are Barbiturates and how do they differ from BZs in terms of safety?
Barbiturates are drugs that act as CNS depressants
They have a higher risk of dependence and fatal respiratory depression compared to BZs
How do BZs modulate GABA-A receptors?
They enhance the effect of GABA by binding to an allosetric site (location on the receptor that’s separate from the active site), increasing chloride influx and inhibition
What does the Diazepam Binding Inhibitor (DBI) do?
DBI is an endogenous modulator of GABA-A receptor fucntion, affecting inhibition in the brain
What are presynaptic receptors?
receptors located on the neurone terminals that modulate neurotransmitter release
What’s the role of autoreceptors?
The provide negative feedback to reduce neurotransmitter release, synthesis or storage
How do heteroreceptors differ from autotrceptros
Heterorecptors modulate neurotransmitter release of another neuron and autoreceptos modulate thier own neuron’s transmitter release
Can heteroreceptors be excitatory?
Yes - heteroreceptors can enhance neurotransmitter release in the second terminal
What do Monoamine Oxidase Inhibitors (MAOIs) do?
They inhibit monoamine oxadise enzymes, preventing neurotransmitter breakdown and increasing levels in the synaptic cleft
How do SSRIs alleviate the symptoms of depression?
They block serotonin reuptake, increasing the avaliability in the synpatic cleft
What drug(s) prevent action potentials by blocking sodium channels?
Tetrodotoxin or some local anesthetics
Name a drug that inhibits neurotransmitter reuptake
Cocaine - blocks dopamine reuptake, increasing its concentration in the synaptic cleft
Which drug increases dopamine sythesis?
L-DOPA is used to increase dopamine synthesis in Parkinson’s disease
What drug is used to prevent neurotransmitter storage?
Reserpine blocks the storage of neurotransmitters like dopamine, norepinephrine and serotonin in vesicles
How does reserpine affect neurotransmitter availability?
It prevents neurotransmitter storage in vesicles, reducing availability for release
What is the biological basis of reward and addiction?
Reward + addiction are linked to the dopaminergic pathways in the brain, particularly the mesolimbic dopamine system
How is dopamine involved in addiction?
Drugs of abuse increase dopamine release in the nucleus accumbens, reinforcing drug-seeking behaviour
What is the primary neurotansmitter associated with Sz?
Dopamine –> overactivity in dopaminergic pathways contributes to Sz symptoms
What neurotransmitter imbalance is implicated in depression?
Reduced levels of serotonin, norepinephrine and dopamine
How are dopamine antagonists used in Sz treatment?
They block dopamine receptors, reducing overactivity linked to psychotic symptoms
What are benzodiazepines used for clinically?
Treating anxiety, insomnia and muscle relaxation
Why are barbiturates less commonly used now?
Due to high potential for dependence ad fatal respiratory depression
What is the difference between ionotropic and metabotropic receptors?
Ionotropic receptors directly gate ion channels, while metabotropic receptors modulate intracellular reactions.
Why is it important to understand drug mechanisms in neuropharmacology?
To relate drug actions to their therapeutic uses and side effects.
What natural source produces atropine?
Atropine is derived from the deadly nightshade plant (belladonna).
What is nicotine’s mechanism of action?
It acts as an agonist at nicotinic acetylcholine receptors.
