Drug Affinity Flashcards Preview

BMS 242 Core Physiology and Pharmacology > Drug Affinity > Flashcards

Flashcards in Drug Affinity Deck (33)
Loading flashcards...
1

What is a constant in drug receptor theory

affinity of drug for receptor

2

How can affinity of a drug be determined

ligand binding assays

3

What is affinity

how tightly the drug and receptor interact

4

What is the measurement of affinity

KD

5

When is KD measured

at equilibrium

6

Describe the relationship between KD and affinity

inverse relationship

7

Describe the affinity if the KD value is low

high affinity

8

What is KD

Concentration of drug required to occupy 50% of receptors

9

Why is the relationship between KD and affinity inverse

the better the drug is at binding the lower the conc to occupy receptors

10

What is the efficacy value for agonists

high

11

What type of drug has no response of efficacy

antagonists

12

What does efficacy govern

activation

13

What is EC50

effective concentration giving 50% of maximal response

14

What is the receptor reserve

spare receptors

15

What can efficacy of an agonist influence

size of response

16

What does ACh bind to (guinea-pig ileum)

GPCR muscarinic receptor

17

What happens when ACh binds to GPRC muscarinic receptors (guinea-pig ileum)

Gq proteins activate, generate a second messenger

18

What does the second messengers trigger (guinea-pig ileum)

rise in intracellular calcium

19

What does the rise in intracellular calcium trigger (guinea-pig ileum)

activation of contractile machinery - contraction

20

What is drug concentration to response curves plotted on

semi logarithmic scale

21

What does the sigmoidal curve hill equation fit to

concentration response curve

22

What value does the Hill slope tend to be

around 1

23

When would you have two agonists bind at once

nicotinic receptors

24

What does the hill slope value tend to be when two agonists bind

around 2

25

Describe the relationship between drug potency and EC50

low EC50 values are more potent

26

Describe the relationship between affinity and potency

as affinity increases potency increases

27

What factors determine potency

affinity, efficacy and spare receptors

28

What is the efficacy of partial agonists

partial agonists have an efficacy less than 1

29

What is KD value the same as for partial agonists

KD=EC50

30

What is the efficacy of full agonists

1