M&R Session 8- Receptors And Drug-receptor Interactions Flashcards Preview

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Flashcards in M&R Session 8- Receptors And Drug-receptor Interactions Deck (24)
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0
Q

Do agonists have efficacy or affinity?

A

Both.

1
Q

What are agonists?

A

They bind to receptors and cause a response.

2
Q

What are antagonists?

A

Drugs that bind to receptors but don’t cause a response.

3
Q

Do antagonists have efficacy or affinity?

A

Affinity only.

4
Q

What do antagonists do?

A

They prevent agonists from binding to receptors and therefore prevent receptor activation by agonists.

5
Q

What is intrinsic efficacy?

A

The ability to produce an active form of a receptor ligand complex.

6
Q

What is efficacy?

A

The ability to produce a desired/intended response.

Determined by cell and tissue factors.

7
Q

Why does an antagonist not produce a response?

A

Because it has no intrinsic efficacy, therefore cannot activate the receptor.

8
Q

What is Kd?

A

The amount of ligand required to achieve 50% occupancy of available receptors.

9
Q

What does a small Kd represent?

A

A high affinity. It means that less drug is required to achieve 50% occupancy.

10
Q

What is the relationship between Kd and affinity?

A

Inverse proportion

11
Q

What does response require?

A

Drug efficacy

12
Q

What is EC50?

A

The effective concentration that gives 50% of the maximum response.

13
Q

When should the term dose and concentration be used with regard to drugs?

A

Concentration- when the concentration of the drug is known at the site of action.
Dose- when the concentration is unknown at the site of action.

14
Q

What does potency depend on?

A

Affinity and intrinsic efficacy

15
Q

What is potency?

A

It is a measure of drug activity.

16
Q

Why is it important that receptors are selective and specific? E.g beta 2 adrenoreceptors when treating asthma?

A

So that the drug being used only acts in the beta 2 receptor in the airways and not on beta 1 receptors for example in the heart to cause increase force and rate of heart contraction.

17
Q

Why do spare receptors exist?

A

Due to signal amplification

18
Q

What is the advantage of having spare receptors?

A

Allows increased sensitivity and therefore responses at low concentrations of agonist.

19
Q

When do receptor numbers tend to increase and why?

A

With low activity in order to increase sensitivity.

20
Q

What are partial agonists?

A

Drugs that can’t produce a max response even when receptors are fully occupied.

21
Q

Give an example of a partial agonist and what it is used for.

A

Opioids,

Pain relief and recreational use (heroin) for euphoria

22
Q

When can a partial agonist become a full agonist and why?

A

When the receptor number is increased because although each agonist has a low intrinsic activity at each receptor, there are sufficient receptors to produce a full response.

23
Q

What is IC50?

A

The concentration of antagonist giving 50% inhibition.

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