Drug Receptor Interactions Flashcards
What is competitive antagonism?
It is the mechanism by which one drug can reduce the effect of another.
What is efficacy?
It’s the parameter that describes the ‘strength’ of the agonist-receptor complex in evoking a response.
What is the result of irreversible competitive antagonism?
Increasing agonist concentration doesn’t overcome antagonism.
How is antagonist potency expressed?
pA2 value.
It is the negative logarithmic of the molar concentration of the antagonist.
What is an inverse agonist?
Binds to the same receptor as an agonist, inducing a pharmacological response that is opposite to an agonist. (Decreases activation)
What is a orthosteric site?
Direct binding to the receptor site.
What is an allosteric site?
It allows binding activity to be turned off/on
What is an allosteric modulator?
Binds to a site other than the site it’s directly responsible for. It indirectly influences the biological response.
What are the two forms of desensitisation?(tachyphlaxis)
Translocation/internalisation of receptor
Uncoupling of receptor from its transduction mechanism.
What causes the uncoupling of the receptor?
Due to the receptors being exposed to continuous presence of agonist.
What is seen on a graph when there is reversible competitive antagonism?
Antagonist present = curve is shifted to the right.
No change in slope or Emax
How is a high potency expressed on as child plot?
A higher pA2 value
What is a irreversible competitive antagonist?
Binds to the same receptor site but dissociates slowly. There’s no change is antagonist occupancy when the agonist is applied.
