Lecture 18 - Review Of Pharmacodynamics Flashcards
What is 0.0001 in exponential/scientific notation?
1x10^-4
What is 10^3 in log notation?
Log(base 10)1000 = 3
What is a ligand?
A substance that can interact with a target protein or receptor
What is an agonist?
A ligand that can interact/bind to a target protein, activating stimulating a biological response
What is an antagonist?
Ligands that have a affinity for a receptor or target protein that dont produce a biological response
Antagonists block the action of agonists
What is affinty?
A measure of strength of the interaction between a ligand/drug binds to a receptor
What measurement is used to define affinty?
Kd
What is Kd?
The concentration of ligament at which 50%of all available receptors are bound
What does a high value of Kd mean?
What does a low value of Kd mean?
High Kd = low affinity of drug (high conc of drug needed to occupy 50% of receptors)
Low Kd = high affinity of drug (low conc of drug needed to occupy 50% of receptors)
What is intrinsic efficacy?
The ability of a ligand to generate the active form of the receptor
What is the notation for the active form of a receptor?
R*
What is ligand efficacy?
The ability of a ligand to cause a measurable biological response
Comprises ligand efficacy and tissues ability to produce response
What is potency?
Essentially how good a drug is at evoking a response
The concentration of a drug that evokes 50% of its maximal response (Emax = EC50)
What does a low EC50 mean?
What does a high EC50 mean?
Low = More potent (less drug required to generate 50% of max response)
High = Less potent (more drug required to generate 50% of max response)
What is Emax?
The concentration of drug needed to reach the maximum response
What is Bmax?
Concentrations of drug required to reach maximum receptors bound
What is a partial agonist?
Ligands that evoke responses that are always lower than the maximum response of a full agonist
How does a full agonists Intrinsic activity compartment to a partial agonists?
Partial agonist = lower intrinsic activity
Full agonist = higher intrinsic activity
What is the difference between an agonists intrinsic efficacy and an antagonists intrinsic efficacy?
Antagonists = no intrinsic efficacy but affinty
Agonist = intrinsic efficacy and affinity
How would a drug with a high intrinsic efficacy Emax compare to a drug with low intrinsic activity?
High intrinsic activity = higher Emax
The larger the max point on a response curve the higher the intrinsic activity
On a response/conc graph how can you determine which drug has the highest potency?
The drug furthest to the left which reaches its EC50 the quickest
On a response/conc curve how can you estimate the affinity of a partial agonist?
For a partial agonist EC50 and its affinity are very similar
What values can be determined from a Porportions of receptor bound - Conc graph for a drug?
Kd (affinity)
Bmax (max binding capacity)
What values can be determined from a Response - Conc graph for a drug?
EC50 (potency)
Emax (intrinsic activity)
