Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ICPP > ICPP 9 Pharmacodynamics > Flashcards

ICPP 9 Pharmacodynamics Flashcards

1
Q

Types of targets for drugs

A

GPCRs
Ion channels
Kinases
Nuclear receptors
Enzymes, transporters, DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are olfactory receptors?

A

Related to smell and taste

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are orphan receptors?

A

Potential drug targets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What a body does to the drug is defined as what?

A

Pharmacokinetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What a drug does to the body is defined as what?

A

Pharmacodynamics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What factor is critical in determining drug action and therefore in what concentration drugs need to be considered in?

A

The concentration of drug molecules around receptors
Molarity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a ligand?
Examples

A

Something that binds to a receptor
e.g. drug, hormones, neurotransmitter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Molarity equation

A

M = g/L divided by MWt (molecular weight)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ligand concentration at receptors usually in which range?

A

Micromolar > nanomolar > picomolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do drugs exert their effects?

A

Binding to a target (mainly proteins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the prefixes for?
10^0
10^-3
10^-6
10^-9
10^-12

A

Molar M 10^0
Millimolar mM 10^-3
Micromolar uM 10^-6
Nanomolar nM 10^-9
Picomolar pM 10^-12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why do most drugs bind reversibly to receptors?

A

Binding is governed by association and dissociation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is avogadro’s number?

A

6x10^23

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

For a ligand to bind to a receptor what must it have?

A

Affinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define affinity

A

A measure of how tightly a ligand binds to its receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the two effects of most drugs?

A

Agonist - activate receptor
Antagonist - block the binding of activating ligands/agonist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define efficacy

A

The ability of a ligand to evoke a response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Relationship between affinity and binding

A

Higher affinity = stronger binding
Lower affinity = weaker binding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is receptor activation governed by?

A

Intrinsic efficacy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Compare and contrast efficacy and affinity in agonists and antagonists

A

Agonists - have affinity, intrinsic efficacy and efficacy
Antagonists - only have affinity (no efficacy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define intrinsic efficacy

A

How good a ligand is at causing a conformational change in its target to produce an active receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Agonist efficacy vs intrinsic efficacy

A

Efficacy - ability of an agonist to elicit a response

Intrinsic efficacy - how good a ligand is at causing a conformational change in its target to produce an active receptor

23
Q

Why is affinity important for a ligand?

A

High affinity allows binding at low concentrations of ligands

24
Q

What is Bmax?

A

Max binding capacity

25
Q

What is Kd?

A

Dissociation constant
Conc. of drug required to occupy 50% of available receptor

26
Q

What can you derive from a bound vs ligand conc. plot?

A

Bmax - mac binding capacity
Kd - conc. of drug needed to occupy 50% of available receptors

27
Q

Relationship between Kd and affinity

A

Low Kd = higher affinity
Reciprocal relationship

28
Q

Which drug has a higher affinity and why?
Drug A: Kd = 10^-9
Drug B: Kd = 10^-3

A

Drug A
lower Kd = higher affinity
Lower conc is needed to occupy 50% of receptors

29
Q

What drug is used to treat morphine/heroin overdose?
How does this drug act?

A

naloxone
High affinity antagonist for u-opioid receptors
Out competes opioids

30
Q

What is naloxone used for?
How does it work?

A

Treat morphine/heroin overdose
High affinity antagonist for u-opioid receptors
Out competes opioids

31
Q

What is the common plot used for drug concentrations vs binding graphs?
Common shape

A

Semi-logarithmic
Drug on x-axis if logarithmic
Sigmoidal shape

32
Q

How can we measure receptor response to agonist?
What can be derived from the plot?

A

Concentration-response curve
Emax - effect max
EC50 - effective concentration giving 50% of maximal response (drug potency)

33
Q

Difference between concentration and dose

A

Concentration - known amount of drug at site of action

Dose - amount of drug at site of action is unknown due to excretion or metabolism

34
Q

What is potency?

A

EC50
Effective conc. giving 50% of the maximal response

35
Q

What does potency depend on?

A

Affinity
Intrinsic efficacy
Cell/tissue specific components

36
Q

Relationship between EC50 and drug potency

A

Low EC50 = high drug potency
Less conc. needed to give 50% of maximal response

37
Q

What do spare receptors indicate?

A

<100% occupancy = 100% response

38
Q

Why do we have spare receptors?

A

Increase sensitivity/potency
Allows responses at low concentrations of agonist

39
Q

What is a partial agonist?

A

Ligand that evoke responses lower than Emax
Lower intrinsic efficacy

40
Q

Outline the relevance of altered receptor number

A

Receptor numbers are not fixed:
- tend to increase with low activity (up-regulation)
- tend to decrease with high activity (down-regulation)

41
Q

In terms of EC50, compare and contrast partial and full antagonists

A

Full - EC50 < Kd
Partial EC50 = Kd

42
Q

How can partial agonists provide antagonism?

A

Can inhibit the effect of another drug
Stops drug from binding

43
Q

Describe the properties of a partial agonist

A

Lower intrinsic activity
Lower efficacy
Insufficient intrinsic efficacy for maximal response
No spare receptors

44
Q

Clinical relevance of partial agonists

A
  • Allow for more controlled response
  • Works in the absence of endogenous ligand
  • Acts as antagonist if high levels of full agonist
45
Q

What are the 3 types of receptor antagonism?

A
  • reversible competitive antagonism
  • irreversible competitive antagonism
  • non-competitive antagonism
46
Q

Outline reversible competitive antagonism

A
  • Same binding site as lignad
  • can be overcome as antagonist dissociates
  • conc-response curve moves right
  • Emax achieved
47
Q

How can a partial agonist become a full agonist?

A

Increasing receptor number to produce a full response

48
Q

What is IC50?

A

Conc. of antagonist that gives 50% inhibition

49
Q

Outline irreversible competitive antagonism

A
  • bind to same site as ligand
  • antagonists dissociate very slowly or not at all - cant be overcome e
  • conc-response curve moves right and down
50
Q

Concentration response curve in reversible competitive antagonism

A

Moves right

51
Q

Concentration response curve in irreversible competitive antagonism

A

Moves right and down

52
Q

Outline non-competitive antagonism

A

Binds to allosteric site + causes change in shape of active site/receptor

53
Q

Apparent volume distribution equation

A

Vd = dose/plasma conc

ICPP (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions