Receptors and membrane signalling

Question 1

What is the receptor concept?

Answer 1

Drugs produce their effects by combining with specific receptor sites in cells
Response is related to the number of occupied receptors

Question 2

What is the lock and key hypothesis?

Answer 2

The shape of the drug complements the shape of the receptor

Question 3

What is affinity?

Answer 3

The strength of the drug-receptor interaction

Question 4

What are agonists?

Answer 4

Drugs that bind to a receptor and produce a response

Question 5

What do agonists possess?

Answer 5

Affinity

Efficacy

Question 6

What are antagonists?

Answer 6

Drugs that bind to a receptor but do not produce a response

Question 7

What do competitive antagonists do?

Answer 7

Prevent agonist binding

Question 8

What do antagonists possess?

Answer 8

Affinity but not efficacy

Question 9

What is efficacy?

Answer 9

Efficacy is a measure of the degree to which an agonist produces a response when binding a given proportion of receptors

Question 10

What is the concept of quantitative pharmacology?

Answer 10

That there is a simple relationship between the amount of drug bound to receptors and the effect produced

Question 11

What is the formula for Kd?

Answer 11

The dissociation constant

Kd= [A][R]/[AR]

Question 12

What is affinity?

Answer 12

The measure of how well a drug binds to the receptor

Question 13

Is a drug response proportional to occupancy?

Answer 13

Yes, but efficacy also involved

Question 14

What is the efficacy of a full agonist?

Answer 14

1

Question 15

What is the efficacy of a partial agonist?

Answer 15

0 to 1

Question 16

Is it possible to have negative efficacy?

Answer 16

Yes, in the case of inverse agonists

Question 17

What are the four categories of drug receptor/targets?

Answer 17

Enzymes
Ion channels
Transporters
Physiological

Question 18

How may cell function be regulated?

Answer 18

Altered membrane potential
Altered enzyme activity
Altered gene expression

Question 19

How are receptors classified?

Answer 19

According to the transmitter or hormone with which they interact

Question 20

What are the five receptor superfamilies?

Answer 20

Integral ion channels
G protein coupled receptors
Integral tyrosine kinases
Cytokine receptors
Steroid receptors

Question 21

What are spare receptors?

Answer 21

Some highly efficacious agonists will produce a maximal response without binding to all available receptors

Question 22

What are partial agonists?

Answer 22

Cannot produce the maximal response from a cell even when bound to all available receptors