Pharmacodynamics I: Receptors, Agonism & Antagonism, Receptor Theory, & Variability of Response Flashcards
What is Pharmacodynamics?
Effect of drug on body
Are Drug-Receptor interactions Reversible or Irreversible?
Reversible
What does an Agonist do?
Binds at a receptor and elicits a response
What does an Antagonist do?
Binds at receptor but elicits NO RESPONSE itself but prevents response to endogenous ligand
What is the Efficacy on a Dose-Response Curve?
Height of curve
e.g. % of maximal response
What is the Potency on a Dose-Response Curve?
EC50
i.e. the lower the EC50, the more potent the drug
What type of drug has an Efficacy, ε = 1
Full agonist
What type of drug has an Efficacy, ε < 1
Partial agonist
What type of drug has an Efficacy, ε = 0
Antagonist
What is the order of Potency of these Agonists?
A > C > B
TRUE OR FALSE:
Partial agonists can have an antagonist effect?
True.
They occupy the receptor binding site and impede access by the endogenous ligand
What is Chemical Antagonism?
Interaction with drug in solution
What is Physical Antagonism?
Two chemicals that produce opposite effects, but act through separate receptor systems
What is Pharmacokinetic Antagonism?
Drug A affects pharmacokinetics of Drug B, altering B at the target tissue
How can Competitive Antagonism be overcome and what does this do to the Dose / Response curve?
- Increasing agonist
- Shifts D/R curve to the RIGHT
TRUE OR FALSE
Non-Competitive Antagonists increase maximal response?
False.
They REDUCE maximal response
Which receptor state do Agonists preferentially bind to?
Activated State (Ra)
* shifts equilibrium towards activation
Which receptor state do Inverse Agonists preferentially bind to?
Resting State (Ri)
*shifts equilibrium towards inactivation
Which receptor state do Antagonists preferentially bind to?
No preference for either
* equilibrium not affected
Which line represents a Full Agonist, Partial Agonist, Competitive Antagonist, and Inverse Agonist?
