#2 Flashcards
What is EC50?
EC50 = effective concentration, describes drug ACTION as opposed to drug BINDING (which can be described using law.
of mass action).
*EC50 is defined as the concentration of drug that provides 1/2 maximum EFFECT.
What is a dose response curve?
A quantitative measurement of a pharmacological effect
What are partial agonists?
An agonist that is sufficiently poor at activation that its best is not good enough to achieve the maximum effect that full agonist achieve. *this ability to activate receptors is independent of its binding affinity!
What are receptor gene families and why are they important in understanding Pharmacology?
Families of receptors that all bind to same drug yet have different effects. This is important because it highlights the complexity of drug action and the importance of specific agonist and antagonist.
Can EC50 be less than Keq?
Yes, it can be equal to or lower than Keq.
A maximal pharmalogical effect is observed when the drug concentration ____________ the EC50.
Greatly exceeds
What is Keq?
Keq is defined as the amount of drug that produces 1/2 maximum BINDING to the receptor.
Are Keq and EC50 the same?
No! b/c often one observes 1/2 maximal effect at less than 1/2 maximal binding (this explains why EC50 can be equal to or less than Keq)
______ is the concentration range where a drug works.
Potency
What determines potency?
efficacy and Binding affinity
______ is the ability to confer the response.
Efficacy
What happens if a drug has insufficient Efficacy?
It will be a partial agonist regardless of how well it binds to its receptor.
What two factors determine the concentration dependance of drug action?
Binding affinity and efficacy
How are agonists segregated?
Into alpha and beta adrenergic receptor groups (not according to whether the activity is excitatory or inhibitory)
