38 Questions
Which drug prevents the storage of neurotransmitters in vesicles in the terminal, thereby decreasing the amount of transmitter available for release?
Reserpine
Where are autoreceptors located?
On the same terminal that releases the transmitter
Which drugs affect the prevention of action potentials by blocking voltage-dependent sodium channels?
Tetrodotoxin
What do you need to be aware of from the presentation related to synaptic transmission?
The different classes of receptors and the distinction between ionotropic and metabotropic receptors
Which drugs affect the metabolism of neurotransmitters?
Tricyclic antidepressants
Where are heteroreceptors located?
On terminals of a different neurone from the one releasing the transmitter
Which drug is used to prevent the release of neurotransmitters?
Black widow venom toxin
What is the role of presynaptic receptors?
Modulates the release of neurotransmitters from the terminal
Which of the following topics is covered in the video on synaptic function?
Receptor activation
What is the primary focus of behavioural neuropharmacology?
Neurotransmitter binding to its receptor
In which state does a neurone rest when a neurotransmitter binds to its receptor?
Resting state
What aspect of brain function does neuropharmacology primarily focus on?
Neurotransmitter synthesis
Which area of brain function does the biological basis of schizophrenia specifically address?
Neurotransmitter binding to its receptor
What is the focus of molecular neuropharmacology?
Neurotransmitter synthesis
What process occurs at the axon hillock?
Signal integration
Which aspect of brain function is covered in the video on synaptic function?
Neurotransmitter binds to receptor
Which type of neuron receptor acts as a negative feedback mechanism to reduce transmitter release?
Autoreceptor
What is the specific compound in the brain known as the brain's 'endozepine'?
Diazepam binding inhibitor (DBI)
Where are GABA-A receptors located?
Postsynaptic membrane
Which type of receptor is located on the terminals of a different neuron and modulates release of transmitters from the second terminal?
Heteroreceptor
What can autoreceptor activation inhibit?
All of the above
What is the role of presynaptic receptors in regulating neurotransmitter release?
Can have opposite effects on the transmitter depending on their location and type
Where are autoreceptors located?
Neuronal terminals
What is DBI's effect on GABA-A receptors?
Positive allosteric modulation
What is the role of reuptake inhibitors in affecting neurotransmitter clearance?
Prevent the re-uptake, leading to a build up of transmitters in the terminal and increased availability to bind to receptors
How do breakdown enzyme inhibitors affect neurotransmitter availability?
Increase the concentration of transmitter in the synaptic cleft, leading to longer availability to bind to receptors
Which statement best describes the action of receptor agonists?
Mimic the effect of the native neurotransmitter, causing excitation or inhibition in the post-synaptic neurone
What is the function of receptor antagonists in affecting neurotransmitter activity?
Bind to receptors but do not change the activity of the post-synaptic neurone, preventing native transmitter or agonist from binding
How do drugs affecting neurotransmitter synthesis using precursors impact transmitter availability?
Increase transmitter synthesis by providing precursors, leading to enhanced transmitter availability in the synaptic cleft
What is the effect of drugs that prevent active reuptake of transmitters from the synaptic cleft into the terminal?
Increase availability of transmitters to bind to receptors for longer and enhance their effect
Which is a characteristic of breakdown enzyme blockers?
Prevent enzymes from breaking down neurotransmitters, leading to increased transmitter concentration in the synaptic cleft and longer availability to bind to receptors
What is the primary action of antagonist drugs at neurotransmitter receptors?
Bind to receptors but do not change activity of post-synaptic neurones, preventing native transmitter or agonist from binding
What type of receptors are located at the synaptic cleft between neurons and have ion channels linked to the neurotransmitter binding site?
Nicotinic acetylcholine receptors
Which type of receptor activation causes intracellular reactions involving g-protein mediated second messenger systems?
Metabotropic glutamate receptors
What type of drugs are used to treat conditions involving underactivity of neurotransmitters by acting on neurotransmitter receptors?
Agonists
Which mechanism involves a substance binding to a second binding site on a neurotransmitter receptor, separate from the main transmitter binding site, and enhances or attenuates the effect of the main transmitter?
Allosteric modulation
Which venom toxin can act as a neurotransmitter receptor antagonist?
Curare
Which type of receptor has ion channels normally closed in the resting state, preventing ions from entering the post-synaptic neuron?
Nicotinic acetylcholine receptors
Study Notes
- Ionotropic receptors are located at the synaptic cleft between neurons, on the post-synaptic neuron dendrite.
- In the resting state, these receptors have ion channels linked to the neurotransmitter binding site, which are normally closed and prevent ions from entering the post-synaptic neuron.
- Activation of ionotropic receptors by neurotransmitter binding opens the ion channel, allowing ions (such as Na+ or Cl-) to enter the neuron and change the membrane potential, resulting in excitation (EPSP) or inhibition (IPSP).
- Examples of ionotropic receptors include nicotinic acetylcholine receptors, GABA-A receptors, and NMDA receptors.
- Metabotropic receptors are also located at the synaptic cleft and on the post-synaptic neuron dendrite.
- In the resting state, these receptors have intracellular signaling cascades linked to the neurotransmitter binding site, which are normally inactive and keep the neuron at rest.
- Activation of metabotropic receptors by neurotransmitter binding causes intracellular reactions, often involving g-protein mediated second messenger systems, leading to changes in membrane potential and excitation or inhibition.
- Examples of metabotropic receptors include metabotropic glutamate receptors, GABA-B receptors, and muscarinic acetylcholine receptors.
- Ionotropic and metabotropic receptors are the two main types of neurotransmitter receptors.
- Therapeutic drugs can act on neurotransmitter receptors to treat various conditions. Agonists are used to treat conditions involving underactivity of neurotransmitters, while antagonists are used to treat conditions involving overactivity.
- Venom toxins, such as curare and bungarotoxin, can act as neurotransmitter receptor antagonists.
- Many drugs, such as antipsychotics, anticonvulsants, anxiolytics, and certain plant derivatives, act on neurotransmitter receptors as agonists or antagonists.
- Allosteric modulation is a process by which a substance binds to a second binding site on a neurotransmitter receptor, separate from the main transmitter binding site, and enhances or attenuates the effect of the main transmitter.
- Allosteric modulation is an important mechanism of neurotransmission, and is used therapeutically, such as the enhancement of GABA-mediated inhibition by barbiturates and benzodiazepines.
Test your knowledge on diazepam and endogenous benzodiazepines with this quiz covering their uses, functions, and related research findings.
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