18 Questions
What is the primary method used to measure the affinity of an agonist?
Using a radioactive-labeled ligand with isolated cell membranes
What is the relationship between receptor occupancy and physiological response?
Sigmoidal, with a threshold occupancy needed for response
What is the purpose of comparing concentration response curves for agonist and agonist + antagonist?
To measure the affinity of the antagonist
What is the relationship between the logarithmic concentration scale and the receptor occupancy curve?
Sigmoidal, with a threshold log(concentration) needed for occupancy
What is the difference between affinity and efficacy?
Affinity refers to the ability to bind, while efficacy refers to the ability to activate a receptor
What is the primary function of a receptor in relation to an agonist?
To switch from its resting state to its activated state upon binding of the agonist
What is the effect of an antagonist on the fractional occupancy of an agonist?
It decreases the fractional occupancy of the agonist.
What is the purpose of the dose ratio in reversible competitive antagonism?
To determine the concentration of the agonist needed to produce the same response in the presence of the antagonist.
What is the effect of increasing the concentration of an antagonist on the receptor occupancy of an agonist?
It decreases the receptor occupancy of the agonist.
What is the unit of the equilibrium dissociation constant for the antagonist (KB)?
Concentration
What is the effect of the antagonist on the RT in the presence of an agonist?
It increases the RT.
What is the relationship between the dose ratio (r) and the EC50 values in the absence and presence of the antagonist?
r = [A`]/[A]
What is the definition of efficacy in the context of receptor binding?
The ability of a drug to activate a receptor once bound
A drug has an efficacy of 0.5. What type of drug is it?
Partial agonist
What is the term for the minimum amount of drug required to produce a certain biological response?
EC50
A full agonist can achieve a maximum response without activating all receptors. What is this phenomenon known as?
Receptor reserve
What is the term for the ability of a drug to bind to a receptor?
Affinity
What is the main assumption of the two-state receptor model?
Receptors can adopt an active state even in the absence of an agonist
This quiz covers the measurement of affinity and KD of drugs, including agonists and antagonists, using radioactive-labeled ligands and concentration response curves. It also explores the relationship between concentration and occupancy. Test your understanding of these pharmacology concepts!
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