DRUG TARGETS 3

Question 1

What is competitive reversible antagonism?

Answer 1

Antagonist competes directly with the agonist for binding to the receptor.
Parallel rightwards shift to the concentration response curve
No change in the maximum response-overcome by increasing the agonist concentration

Question 2

What is competitive non-reversible antagonism?

Answer 2

Antagonist binds to the receptor at the same place that the antagonist binds but doesn’t let go
Non-parallel rightwards shift to the conc-response curve
Overcome by Spare receptor theory- so don’t see a depression in maximum response. In reality should see a depression as the spare receptor is just a theory.

Question 3

What is the potency measure for the competitive reversible antagonism?

Answer 3

pA2

Question 4

What is the potency measure for the competitive non-reversible antagonism?

Answer 4

pD2’

Question 5

What is the difference between pD2 and pD2’?

Answer 5

A pD2 value is a measure of the potency of an AGONIST whereas a pD2’ value is
the measure of the potency of a competitive irreversible or non-competitive antagonist.

Question 6

What is non-competitive antagonism?

Answer 6

The antagonist does not bind at the same site as the agonist.
So cannot be overcome by increasing concentration of agonist.
Here the antagonist affects the signalling pathway initiated by agonist-receptor binding
Non-parallel rightwards shift to the conc-response curve with a depression in max response.

Question 7

What is physiological antagonism?

Answer 7

Occurs when the actions of 2 agonists binding to two different sites produce opposite effects

Question 8

What are partial agonists?

Answer 8

Show full affinity but their efficacy is <1

Question 9

What are inverse agonists?

Answer 9

Show negative efficacy

Are the same as antagonists when receptors show preference for the inactive state.

Question 10

What is constituive activity?

Answer 10

When the receptors show a tendency for an active state without the presence of a ligand.