Agonists and Antagonists.

Question 1

Will a drug that is an agonist of a receptor have an affinity for that receptor?

Answer 1

Yes.

Question 2

What happens when an agonist binds to a receptor?

Answer 2

It will elicit a response.

Question 3

What determines the level of a receptors response following the binding of an agonist?

Answer 3

The efficacy of the drug.

Question 4

Do agonists have affinity or efficacy for their receptors?

Answer 4

Both.

Question 5

Will drugs that are antagonists have affinity for a receptor?

Answer 5

Yes.

Question 6

Will drugs that are antagonists have efficacy for a receptor?

Answer 6

No, as they block the receptor and there will be no response.

Question 7

Do antagonists have affinity or efficacy for their receptors?

Answer 7

Only affinity.

Question 8

What effects will full agonists have on a receptor?

Answer 8

The maximum possible effect.

Question 9

What effects will partial agonists have on a receptor?

Answer 9

They elicit a partial response.

Question 10

Will partial agonists have a higher or lower efficacy than full agonists?

Answer 10

A lower efficacy.

Question 11

Can drug A have a higher affinity than drug B, but a lower efficacy?

Answer 11

Yes.

Question 12

If drug A has a higher affinity than drug B and a lower efficacy, what will be the difference in effect if we give the same dose?

Answer 12

We need less of drug A to get a maximum effect, but the maximum effect is not as high as that of drug B.

Question 13

What effects will antagonists have on receptors?

Answer 13

Always no effect.

Question 14

What is drug potency based on?

Answer 14

Its EC-50.

Question 15

What are equipotent drugs?

Answer 15

Drugs that have the same potency.

Question 16

What is the EC-50 of a drug?

Answer 16

50% of the drugs maximum response.

Question 17

Will drugs with a low EC-50 have a high or low potency?

Answer 17

Drugs with a low EC-50 have a high potency.

Question 18

Can drugs have the same potency, but different efficacies?

Answer 18

Yes.

Question 19

Will high potency full agonists have a high or low EC 50?

Answer 19

A low EC-50.

Question 20

Will low potency full agonists have a high or low EC 50?

Answer 20

A high EC-50.

Question 21

Do we need less or more of a highly potent drug to achieve the same response as that of a less potent drug?

Answer 21

Less.

Question 22

Will weak agonists have strong or weak potency?

Answer 22

Weak potency.

Question 23

Will strong agonists have strong or weak potency?

Answer 23

High potency.

Question 24

How can we tell that a drug has a higher potency that another drug?

Answer 24

The EC-50 will be smaller.

Question 25

Will partial agonists be able to achieve a maximum effect?

Answer 25

No, only full agonists can do this.

Question 26

What will competitive agonists compete against to bind to an enzymes active site?

Answer 26

The enzymes normal substrate.

Question 27

What happens if an antagonist binds to an enzyme instead of its substrate?

Answer 27

It stops the enzyme from working properly.

Question 28

Will an enzymes substrate and its antagonist use the same binding site?

Answer 28

Yes.

Question 29

What will make it more likely that an enzyme will bind to its substrate instead of an antagonist?

Answer 29

If we increase the concentration of substrate then it is more likely that the enzyme will bind to the substrate. However, if we increase the concentration of the inhibitor then it is more likely that the enzyme will bind to the inhibitor.

Question 30

How will non-competitive antagonists bind to enzymes?

Answer 30

They bind to a location of the enzyme that is not the active site.

Question 31

How will non-competitive antagonists affect enzymes?

Answer 31

Binding usually results in a conformational change in the enzyme.

Question 32

What happens after a non-competitive antagonist has bound to an enzyme and caused a conformational change in the enzyme?

Answer 32

The enzyme can no longer bind to its substrate and this results in the enzyme being useless.

Question 33

Will non-competitive antagonists do bind to the same site as the enzyme substrate?

Answer 33

No.

Question 34

How will increasing the amount of a competitive antagonist affect the graph curve for enzyme activity?

Answer 34

If we increase the antagonist for competitive inhibition then we decrease the amount of active enzymes and this means the curve shifts to the right.

Question 35

How will increasing the amount of an agonist affect the graph curve for enzyme activity?

Answer 35

It shifts the curve to the left.

Question 36

How will increasing the amount of a non-competitive antagonist affect enzyme activity?

Answer 36

The more we increase the antagonist, the greater the effect will be until there are no enzymes functioning.

Question 37

Is it possible to overcome the effects of a non-competitive agonist?

Answer 37

No.

Question 38

Inverse agonists have effects on what kind of receptors?

Answer 38

Active receptors.

Question 39

What effects will inverse agonists have on receptors?

Answer 39

They will keep a receptor active, but they will decrease its response.

Question 40

Will a receptor bound to an inverse agonist be more less active than it would be if it was not bound to any agonist?

Answer 40

Less active.

Question 41

What kind of agonists increase the activity of a receptor?

Answer 41

Partial and full agonists.

Question 42

What kind of agonists decrease the activity of a receptor?

Answer 42

Inverse agonists will decrease it.

Question 43

What about drug binding will lead to a better response?

Answer 43

The tighter the ligand binds to a receptor, the better the response will be.

Question 44

Can chiral drugs or enantiomers bind to a receptor?

Answer 44

No, only one form of the drug will bind to the receptor while the other will not.

Question 45

How will using an agonist for a long time affect the amount of drug receptors?

Answer 45

Prolonged use of agonists can lead to the down regulation of receptors.

Question 46

How will using an antagonist for a long time affect the amount of drug receptors?

Answer 46

It leads to up-regulation of receptors.