Efficacy and Partial Agonists

Question 1

What is efficacy and what does it depend on?

Answer 1

1. The ability of a drug to activate a receptor and cause a response (EFFECT)
2. Depends on the number of receptors occupied and

Question 2

What is E max?

Answer 2

The maximum response an agonist can achieve

Question 3

What type of Emax does a partial agonist have?

Answer 3

Lower Emax

Question 4

What is a partial agonist?

Answer 4

They partially bind to the receptor sites and can never evoke the maximum Emax response even though 100% of receptor sites may be binded

Question 5

How is a partial agonist used in medicines and give an example?

Answer 5

1. Used due to less desensitisation compared to normal agonists and can be used as competitive inhibitors against agonists
2. Buprenorphine- used as a partial agonist as it reduce pain but not give all the other side effects of morphine

Question 6

What is the term that explains how maximum response can be created without 100% of the receptor sites being binded and explain it?

Answer 6

1. Receptor Reserves- a proportion of receptors in the tissues that are never used
2. A signal amplification must occur for it to activate

Question 7

What is the inverse agonist?

Answer 7

1. Has some actions that are similar to agonists but can also have the complete opposite response- it blocks the individual activity of the agonist as well (not just receptors)
2. Equilibrium between agonist and inverse as they switch between the two

Question 8

What are state are receptors constantly in? And which do agonists prefer?

Answer 8

1. Constant equilibrium between active and non active state

2. Agonists prefer the active state