Introduction to Drug Action

Question 1

What does pharmacodynamics mean?

Answer 1

How the drug works on the body - biological effects, mechanism of action etc

Question 2

What does pharmacokinetics mean?

Answer 2

What the body does to the drug - metabolism, absorption etc

Question 3

What is a drug?

Answer 3

Narrowly:
Any synthetic, or natural, substance used in the treatment, prevention, or diagnosis of disease

More broadly:
Everyday substances (caffeine, nicotine, ethyl alcohol)
Illicit substances (cannabis, heroin, cocaine)

Question 4

For a drug to be a useful therapeutic agent what must it be?

Answer 4

Selective

Question 5

What does selectively result from?

Answer 5

Chemical structure of the drug

Target recognising only ligand of a precise type

Question 6

What are the targets in which drugs can bind to?

Answer 6

Regulatory proteins: 
- Enzymes
- Carrier molecules 
- Ion channels 
- Receptors 
Additional targets
- RNA 
- DNA

Question 7

What are receptors?

Answer 7

Macromolecules that medicate biological actions of hormones and neurotransmitters

Question 8

What is an Agonist?

Answer 8

A drug that binds to a receptor to PRODUCE A CELLULAR RESPONSE

Question 9

What is an ANTAGONIST?

Answer 9

A drug that BLOCKS THE ACTIONS OF AN AGONIST

Question 10

What is a ligand?

Answer 10

A molecular that binds to another (usually larger molecule)

Question 11

Describe the term affinity?

Answer 11

Strength of association between ligand and receptor - high affinity = longer time that they stick together. High affinity = slow dissociation rate

Question 12

Describe the term Efficacy?

Answer 12

Ability of a drug to produce a biological effect - ability of a drug to produce a biological effect. Higher efficacy = bigger response

Question 13

Agonists posses?

Answer 13

Affinity and Efficacy

Question 14

Antagonists posses?

Answer 14

Only affinity as they do not produce a cellular response

Question 15

What does the term saturation mean?

Answer 15

when all the receptors are occupied

Question 16

What is potency?

Answer 16

Measure of effectiveness for a drug to produce a response (A is more potent that B as it produces a response at 0.01, where as B only produces a response at 1)

Question 17

How would you describe the relationship between (agonist) concentration and response on a linear plot?

Answer 17

Hyperbolic

Question 18

What is EC50?

Answer 18

The concentration of agonist that elicits a half maximal response

Question 19

How would you describe the relationship between (agonist) concentration and response on a semi-logarithmic plot?

Answer 19

Sigmoidal (also better as more accurate, concentration (x axis) more detailed)

Question 20

What is a partial agonist?

Answer 20

an agonist that does not produce a maximal response

Question 21

Describe competitive antagonism?

Answer 21

When the binding of the agonist and antagonist occur at the same orthosteric point. They compete for that receptor

Question 22

Describe non competitive antagonism?

Answer 22

When the agonist and antagonist bind at different active sites, allosteric site. Both can be bound at the same time, however receptor cannot be activated if antagonist is bound

Question 23

What does competitive antagonism cause on the concentration response curve for an agonist acting at the same population of receptors?

Answer 23

Causes a parallel right shit with no depression of curve.

Question 24

What does non competitive antagonism cause on the concentration response curve for an agonist acting at the same population of receptors?

Answer 24

Depresses the slope and maximal response but causes no shift.