Ch 5: Pharmacodynamics

Question 1

It is important to note that the potency of a drug implies nothing about its…

Answer 1

…maximal efficacy.

p. 46

Question 2

We can define a receptor as…

Answer 2

…any functional macromolecule in a cell to which a drug binds to produce its effects.

(p. 46)

Question 3

When a drug binds to a receptor, all that it can do is _____ or _____ the actions of __________ regulatory molecules.

Answer 3

mimic
block
endogenous

(p. 46)

Question 4

Drugs cannot give cells ___ _________. Rather, drugs can only alter the rate of ___________ _________.

Answer 4

new functions
preexisting processes

(p. 47)

Question 5

Drugs cannot make the body do anything that…

Answer 5

….it is not already capable of doing (except in the case of gene therapy).

(p. 47)

Question 6

In theory, it should be possible to synthesize drugs that can alter the rate of…

Answer 6

…any biologic process for which receptors exist.

p. 47

Question 7

What are the 4 primary receptor families?

Answer 7

cell membrane-embedded enzymes
ligand-gated ion channels
G protein-coupled receptor systems
transcription factors

(p. 47)

Question 8

Where does the G protein-coupled receptor get its name?

Answer 8

It binds guanosine triphosphate (GTP).

p. 47

Question 9

Describe the receptors that couple to G proteins.

Answer 9

They are serpentine structures that traverse the cell membrane 7 times.

(p. 48)

Question 10

Transcription factors differ from the other 3 types of receptors in what 2 ways?

Answer 10

Transcription factors are located inside the cell rather than on the surface.
Responses to activation of these receptors are delayed.

(p. 48)

Question 11

What is the simple occupancy theory?

Answer 11

(1) the intensity of the response to a drug is proportional to the number of receptors occupied by that drug and that (2) a maximal response will occur when all available receptors have been occupied.
(p. 49)

Question 12

True or false: the simple occupancy theory can explain all important aspects of dose-response relationships.

Answer 12

False!

p. 49

Question 13

What is affinity as it pertains to the modified occupancy theory?

Answer 13

Affinity refers to the strength of the attraction between a drug and its receptor.

(p. 49)

Question 14

Drugs with a high affinity are very…

Answer 14

… potent.

p. 49

Question 15

What is intrinsic response as it pertains to the modified occupancy theory?

Answer 15

The ability of a drug to activate a receptor upon binding.

p. 49

Question 16

Drugs with high intrinsic activity have…

Answer 16

….high maximal efficacy.

p. 49

Question 17

Drugs that MIMIC the body’s own regulatory molecules are called…
Drugs that BLOCK the body’s own regulatory molecules are called…

Answer 17

agonists (i.e. they activate receptors)
antagonists (i.e. they prevent receptor activation)

(p. 50)

Question 18

What is a partial agonist?

Answer 18

A drug that mimics the body’s own regulatory molecules but produces a response of only intermediate intensity.

(p. 50)

Question 19

In terms of the modified occupancy theory, what characteristics do antagonist drugs have?

Answer 19

These drugs have an affinity for a receptor, but no intrinsic activity.

(p. 50)