What is the present knowledge on Receptors of Analgesics

Question 1

How many different receptors are involved and what is the ratio?

Answer 1

4 receptors, 3 analgesic, 1 non-analgesic.

Question 2

What are the 4 receptors calles and which is analgesic and non-analgesic?

Answer 2

Analgesic Receptors:
1. mu receptor
2. Kappa receptor
3. Delta receptor
Non-Analgesic receptors:
1.  Sigma receptor.

Question 3

Describe the properties of the mu receptor

Answer 3

Morphine binds strongest here, but binding leads to undesirable side effects: Respiratory arrest, euphoria and addiction.

Question 4

Describe the properties of the kappa receptor

Answer 4

Morphine binds less strongly here, but the biological response is analgesic with sedative effects. There are no hazardous side effects.

Question 5

Describe the properties of the delta receptor

Answer 5

This is where the brain’s natural pain killers bind to - enkephalins. Morphine binds strongly here.

Question 6

Describe the properties of the sigma receptor

Answer 6

This is a non-analgesic receptor that morphine can bind to and is associated with hallocinogenic side effects (Hallucinations) so we want to block this receptor.

Question 7

When designing a derivative of morphine, which receptors would we want to activate, and which not to activate?

Answer 7

The mu receptor: Antagonist to block the response
The Kappa receptor: Agonist to get analgesic and sedative effect with no hazardous side effects
The delta receptor: Agonist for analgesic effect
The Sigma receptor: Antagonist to prevent Hallocinogenic side effects