9.12 Pharmacology 3 Flashcards
components on or within the cell to which a substance binds
receptors
How do surface receptors act as ion channels?
directly alter membrane permeability
How do surface receptors act to directly influence cell function?
enzymatically
Purpose of surface receptors linking to regulatory proteins
regulatory proteins control other chemical or enzymatic processes
affinity
- attraction of a drug to a receptor
- determines how it will bind and react
efficacy
How well a drug binds and reacts to with a receptor
How do drugs affect change through binding?
The drug finds and occupies a receptor, then somehow interacts with it to change cell function
agonist
drug that can bind to a receptor and initiate a change
What do agonist drugs have?
- affinity
- efficacy
Antagonists ONLY have
affinity
How do antagonists work?
- binds to receptor
- does not initiate a change
- blocks the effect of another chemical and prevents action
antagonists aka
blockers
beta blockers are used to treat
HTN
competitive antagonist
both the agonist and the antagonist have an equal opportunity to occupy the receptor
For a competitive antagonist vs. an agonist, which will win out for receptor spots?
whichever has the highest concentration
What happens if a competitive antagonist “wins”?
inhibition
Competitive antagonists generally require a (higher/lower) concentration. Why?
- higher concentration
- weak bones
noncompetitive antagonist
- irreversible
- strong bonds formed
- cannot be displaced by the agonist
How long do noncompetitive antagonist drugs last?
- entire lifespan of the cell
- usually several days
partial agonist
- don’t get a full response
Partial agonists have:
- affinity
- don’t have full efficacy
Clinical advantage to partial agonist drugs?
fewer side effects
i.e. cardiovascular and antipsychotics
mixed agonist-antagonist
can stimulate certain receptors while blocking others
Example of mixed agonist-antagonist
selective estrogen receptor modulator (ex. tamoxifen used in breast cancer)
