Receptors and the effects of drugs

Question 1

What is the purpose of the patch clamp technique?

Answer 1

A method for looking at responses generated by individual receptors

Question 2

Name the types of antagonism

Answer 2

Competitive antagonists
Irreversible
Allosteric
Channel blockers
Physiological

Question 3

What are competitive reversible antagonists?

Answer 3

Produce a parallel shift to the right of agonist log D/R
Compete with agonist for the same binding site
Binds reversibly
Decreases the probability of the agonist binding

Question 4

What is the concentration ratio?

Answer 4

The ratio of the concentration of an agonist that produces a specified response in the presence of an agonist, to the agonist concentration that produces the same response in the absence of the antagonist

Question 5

How do you calculate concentration ratio?

Answer 5

EC50agonist alone/EC50with antagonist

Question 6

What is an irreversible antagonist?

Answer 6

Compete with the agonist for the same binding site
Antagonist binds irreversibly
Decrease in maximal response

Question 7

What is a non-competitive antagonist?

Answer 7

Binds at a different binding site
Prevents the effect of the agonist without preventing it binding
Effect is insurmountable

Question 8

What is an allosteric antagonist?

Answer 8

Binds reversibly at a distinct site from the agonist decreasing agonist affinity
Reduces likelihood of agonist binding

Question 9

What are channel blockers?

Answer 9

Bind inside the channel and prevent the passage of ions

Enhanced by receptor activation

Question 10

What are physiological antagonists?

Answer 10

Produce opposite effects on a tissue

Produce a non-selective suppression of the response

Question 11

What is desensitisation?

Answer 11

Prolonged or repeated exposure to an agonist reduces the response to that drug
Receptors are inactivated or body compensates to cancel out effect