Questions and Answers
Where are nuclear receptors typically located in a cell?
Intracellular
What is the effect of glucocorticoid drugs such as prednisolone?
Anti-inflammatory
What is the difference between an agonist and an antagonist?
Agonists bind to and activate receptors, while antagonists bind to, but do not activate receptors
How do blockers work on ion channels?
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What is an example of a substrate analogue inhibitor?
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What is the function of Gaq protein in G protein-coupled receptors?
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What is an example of a false substrate for an enzyme?
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What is the effect of GPCR activation in airway smooth muscle?
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What is an example of a pro-drug?
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What is the location of enzyme-linked receptors and what do they respond to?
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What is the function of transporters in cells?
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What is the function of the enzyme tyrosine kinase in insulin receptor signaling?
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What is the role of Gs protein in GPCR signaling?
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What type of receptor is responsible for the action of insulin in reducing blood glucose levels?
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What is the time scale of action for enzyme-linked receptors?
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What is the common feature of GPCRs, enzyme-linked receptors, and nuclear receptors?
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What is the primary mechanism of signal transduction for G protein-coupled receptors?
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What is the primary difference between enzyme-linked receptors and G protein-coupled receptors?
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What is the role of agonists in receptor-ligand interactions?
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What is the time scale of action for G protein-coupled receptors?
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What is the primary function of second messenger systems in signal transduction pathways?
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What is the main characteristic feature of ion channel receptors?
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What is the role of G proteins in signal transduction pathways?
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What is the primary difference between receptors and enzymes as drug targets?
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What is the key characteristic that distinguishes receptor superfamilies?
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What is the role of ACh binding in nicotinic acetylcholine receptors?
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What is the common feature of ion channel receptors?
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What happens to the ion channel when no agonist is present in ion channel receptors?
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What is the primary function of ion channel receptors?
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How do ion channel receptors respond to agonist binding?
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What is the significance of receptor superfamilies in understanding signal transduction?
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What is the key aspect of signal transduction in ion channel receptors?
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Where are ion channel receptors typically located in a cell?
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What is the time scale of action for ion channel receptors?
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What type of receptors do hormones and slow neurotransmitters typically bind to?
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What is the function of the Ga protein subunit in G protein-coupled receptors?
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What is the purpose of using Pancuronium in anaesthesia?
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What type of receptors do Salbutamol and muscarinic acetylcholine receptors belong to?
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What is the role of GDP and GTP in G protein-coupled receptors?
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How many transmembrane domains do G protein-coupled receptors typically have?
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Study Notes
Nuclear Receptors
- Location: intracellular
- Effector: gene transcription
- Respond to: steroid hormones, other factors
- Time scale of action: hours, very slow
- Examples: glucocorticoid, other steroid hormones
Glucocorticoid Receptor
- Responds to cortisol and glucocorticoid drugs like prednisolone, which are effective anti-inflammatory agents
Protein Targets for Drug Action
- Receptors
- Agonists bind to and activate receptors
- Antagonists bind to, but do not activate receptors
- Ion channels
- Blockers physically plug the ion channel
- Modulators bind to accessory sites and modulate channel activity
- Enzymes
- Substrate analogues competitively inhibit the enzyme
- Some drugs act as false substrates for enzymes
- Pro-drugs must be enzymatically converted to become active
- Transporters
- Specific carrier proteins transport ions and small organic molecules across cell membranes
Receptor Superfamilies
- 4 major types: ion channel receptors, G protein-coupled receptors, enzyme-linked receptors, and nuclear receptors
- Distinguished based on how they transduce the signal, not on which chemical signals stimulate them or the nature of the change in cell function
Ion Channel Receptors
- Location: cell membrane
- Collection of proteins form central pore/channel
- No agonist, ion channel closed, no ion flow
Enzyme-Linked Receptors
- Location: membrane
- Effector: enzyme
- Respond to: metabolism, growth, differentiation
- Time scale of action: minutes, slow
- Examples: insulin receptor, receptors for cytokines, growth factors
Insulin Receptor
- Insulin binds to receptor, reducing blood glucose levels in diabetes
G Protein-Coupled Receptors
- Location: membrane
- Effector: enzyme or channel
- Respond to: hormones, slow neurotransmitters
- Time scale of action: seconds, fast
- Examples: adrenoceptors, muscarinic acetylcholine receptors
G Proteins
- Intracellular effector systems or 2nd messenger cascades
- Guanosine nucleotide binding proteins, GTP and GDP
- Comprise 3 subunits (a, b, g)
- Main classes of Ga protein: Gas activates adenylate cyclase, Gai inhibits adenylate cyclase
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Description
This quiz covers the characteristics of nuclear receptors, their location, effectors, and response to steroid hormones. It also delves into the glucocorticoid receptor and its response to cortisol and glucocorticoid drugs.