Pharmacodynamics

Question 1

How do drugs exert effects?

Answer 1

Bind to a target (usually a protein e.g. G protein)

Question 2

What is critical to determining drug a action?

Answer 2

Concentration of the drug around a receptor

Question 3

What are the different concentrations compared to a mole?
M
mM
MicroM
nM
pM

Answer 3

mM- 10-3M
MicroM- 10-6M
nM- 10-9M
pM- 10-12M

Question 4

What do we consider drug concentrations in?

Answer 4

Moles

Question 5

How do most drugs bind to receptors?

Answer 5

Reversibly

Associates and dissociates

Question 6

What is a ligand?

Answer 6

A molecule or ion that binds specifically to a receptor

Question 7

What do most drugs do?

Answer 7

Block binding of endogenous agonist

Or active a receptor

Question 8

What must a receptor have to bind to a receptor?

Answer 8

Have affinity for it

Higher affinity means stronger binding

Question 9

What does an antagonist do?

Answer 9

Binds but does no activate

Question 10

What does an agonist do?

Answer 10

Bind and activate

Question 11

What is efficacy?

Answer 11

The ability of a ligand to cause a measurable response

Question 12

What does intrinsic efficacy mean?

Answer 12

Can activate the receptor

Question 13

What kind of drugs do not have efficacy?

Answer 13

Antagonists

Question 14

How do we measure drug- receptor interactions by binding?

Answer 14

Radioactive labelled Ligands

Question 15

What is Bmax?

Answer 15

Maximum binding capacity

Question 16

What is Kd?

Answer 16

50 percent occupancy of available receptors 
Dissociation constant 
Index of affinity
Lower value is a higher affinity 
Obtained by radioligand binding

Question 17

What does a high affinity make possible?

Answer 17

Binding at low concentrations

Question 18

What is the drug concentration like on a graph?

Answer 18

Logarithm- fixed base raised to a particular number

Question 19

What does a response of a drug require?

Answer 19

Efficacy

Question 20

What could the response of a Drug be?

Answer 20

Change in the signalling pathway

Change in cell or tissue behaviour

Question 21

What is EC50?

Answer 21

Effective concentration giving 50 percent of the maximal response
The potency

Question 22

What is a dose?

Answer 22

Concentration at site of action unknown (in mg or mg/kg)

Question 23

What is the concentration of a drug?

Answer 23

Known concentration of a drug at site of action

Question 24

For a ligand to have potency what does it need?

Answer 24

Affinity
Intrinsic efficacy
Efficacy

Affinity+efficacy =potency

Question 25

What kind of receptor does asthma affect?

Answer 25

B2- adrenoreceptor

Agonist for treatment

Question 26

What is the problem with treating asthma?

Answer 26

B adrenoreceptors are also found in the heart

Would increase force and rate

Question 27

How can you achieve specificity with drugs?

Answer 27

By selective efficacy of selective efficacy

Question 28

What does there being spare receptors mean?

Answer 28

50 percent binding can give 100 percent response

Question 29

Why do we have spare receptors?

Answer 29

Increases sensitivity as allows responses at low concentrations of agonists

Question 30

Are receptor numbers fixed?

Answer 30

No

Tend to increase with low activity and decrease with high activity

Question 31

What are partial agonists?

Answer 31

Can not produce maximal response
Allows a more controlled response
Works in low levels of ligand

Question 32

What is burenorphine?

Answer 32

Higher affinity than morphine but lower efficacy
Good for pain control
Used to enable withdrawal from other opioids

Question 33

Why would a heroin addict feel ill if injects buprenorphine instead?

Answer 33

Withdrawal or abstinence syndrome

Partial agonism- inhibits heroin effects

Question 34

How can partial Agonists become full agonists?

Answer 34

More receptors generate the full response

Question 35

What does a reversible competitive agonist cause the curve to do?

Answer 35

Shift to the right