Agonists and Antagonists

Question 1

What is competitive antagonism?

Answer 1

Antagonist competes for the binding site so reduces the occupancy of the agonist. The effect is surmountable by increasing the concentration of the agonist.

Question 2

Which way does the presence of a competitive antagonist shift the dose response curve?

Answer 2

To the right, with no change in slope.

Question 3

What is the difference between agonists and partial agonists?

Answer 3

Partial agonists have intermediate efficacy, so can’t elicit the maximum response.

Question 4

What is the dose ratio?

Answer 4

The amount that at dose-response curve is shifted to the right by the presence of the competitive antagonist - the ratio by which the agonist concentration must be increased to restore the normal response level.

Question 5

What is irreversible antagonism?

Answer 5

The antagonist forms strong covalent bonds with the receptor so can’t be displaced by the agonist. the antagonism is insurmountable.