Brainscape's Knowledge GenomeTM

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


See full index

Foundations of Medicine > Pharmacology > Flashcards

Pharmacology Flashcards

1
Q

What is a receptor?

A

A macromolecule in the membrane or inside the cell that chemically binds a ligand (drug).

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

What are different receptors activated by?

A

Different (sometimes the same) signalling molecule

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

How many different receptors exist?

A

4

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

What are the four different types of receptors?

A

Ionotropic receptor channel
Receptor enzyme
Integrin receptor
G-Protein coupled receptor

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

What is an ionotropic receptor?

A

A receptor that is also an ion channel

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

What is a receptor enzyme?

A

Receptor that functions as an enzyme

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

What is an integrin receptor?

A

Receptor that directly affects an enzymes activity

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

What does a G-protein coupled receptor look like?

A

7 transmembrane spanning segments

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

What type of response can a receptor evoke?

A

Membrane permeability
Metabolism
Secretory activity
Rate of proliferation or differentiation
contractile activity
The process is called signal transduction

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

What type of chemical messenger binds to an intracellular receptor?

A

A lipid soluble receptor, steroid hormones

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

Where are the receptors found that can influence the transcription of DNA?

A

Within the nucleus

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

What response can steroids have on transcription?

A

They are a transcription factor and can alter the rate of transcription

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

What are the tyrosine kinase receptor enzymes involved in?

A

Proliferation and differentiation

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

Define affinity

A

The extent which a drug binds to receptors at any given drug concentration or the firmness with which the drug binds to the receptor.

It is the strength of chemical attraction between the drug and the receptor

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

Define efficacy

A

The maximum response that can be achieved with a drug.

It determines how good the drug is at activating the receptor

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

When will you get the maximum response from a drug?

A

When all the relevant receptors are bound to the drug

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

Why is the concentration / response graph curved?

A

Because it is more likely for a ligand to hit a free receptor at the start of a reaction then the end

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

What is the EC50?

A

It is the concentration of a drug at half of its maximal response

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

What graph is used to determine the EC50?

A

The log of drug concentration against the increasing response

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

What does the EC50 indicate?

A

The affinity of the drug for the receptor, a smaller EC50 indicates a smaller amount of drug is needed to evoke the same response, therefore the drug has a higher affinity

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

How does efficacy affect the EC50?

A

It doesn’t

22
Q

What is an agonist?

A

It mimics the normal effect of the receptor

23
Q

What is an antagonist?

A

It blocks the normal effect of the receptor

24
Q

How many different receptors can a strand of drug bind to?

A

As many as the drug has conformational shapes to the receptor

25
Q

What are the sources of calcium ions?

A

Internal stores via inisitol triphosphate

From outside the cell via ligand or voltage gated channels
Via inhibition of calcium transport out the cell

26
Q

What are the effects of calcium in the cell?

A

Can regulate the activity of the target protein e.g of Protein Kinase C

Can bind to calmodulin which directly activates a target protein

Works via some other calcium binding protein e.g troponin

27
Q

What is a secondary messenger?

A

Second messengers are small molecules and ions that relay signals received by cell-surface receptors to effector proteins.

28
Q

What are the possible effects of a secondary messenger?

A

Make channels open wider

Regulate protein synthesis

Regulate the release of calcium

Regulate the synthesis of RNA in the nucleus

Might act on microtubules making things secrete things out of the cell

29
Q

What is intracellular calcium?

A

Intracellular calcium ([Ca2+]i) is a secondary messenger which regulates numerous cellular processes and, therefore, its concentration is tightly regulated.

30
Q

Intracellular calcium storage

A

Organelles which repetitively release and then reaccumulate Ca2+ ions in response to specific cellular events

eg - mitochondria and the endoplasmic reticulum.

31
Q

What does the size of the response depend on?

A

Drug affinity - does it bind to a receptor?
Drug efficacy - does it activate the receptor?

32
Q

What happens to a subunit of a G protein when the G protein coupled receptor is activated?

A

It regulates an enzyme that produces a secondary messenger, e.g

Regulates adenyl cyclase, which in turn produces the second messenger cAMP (cyclic AMP)

This in turn regulates the activity of another enzyme, PKA (protein kinase A) which then goes off to phosphorylate proteins

33
Q

What happens when phospholipase C is regulated?

A

Two secondary messengers are regulated, these (diacylglycerol and Inisitol triphosphate) - These are responsible for activation of Protein Kinase C and the release of calcium ions from internal stores

34
Q

Give examples of receptors with intrinsic enzyme activity

A

Tyrosine kinases
Receptor guanylyl cyclases - retina

35
Q

What type of enzyme can receptors interact with directly?

A

JAK kinases

36
Q

What are JAK kinases involved in?

A

Protein synthesis

37
Q

What is the result of activation of Adenylyl cyclase by a G protein?

A

Makes cAMP (secpndary messenger) which activates a protein kinase

38
Q

What can one signalling molecule act on?

A

Several receptor subtypes

39
Q

What is an example of one signalling molecule that can act on several receptor subtypes?

A

Adrenaline – the endogenous agonist activates all adrenoceptors (α1, α2, β1, β2) like a “master key”

40
Q

What are selective agonists?

A

Drugs that activate only some of those receptors

41
Q

What is an example of a selective agonist?

A

Salbutamol - a β2 agonist

Used in treatment of asthma

42
Q

What is a selective antagonist?

A

Drugs that block only some of those receptors

43
Q

What is an example of a selective antagonist?

A

Propranolol - a β1 and β2 antagonist

Used in treatment of arrythmias

44
Q

An antagonist at a pharmacological receptor is likely to have what combination of affinity and efficacy?

A

High affinity and no efficacy

Pharmacological antagonists are characterised by having high affinity (so bind readily to the receptor) but low or no efficacy (so have no effect, and stop the ligand binding to prevent its effect too).

45
Q

An agonist at a pharmacological receptor is likely to have what combination of affinity and efficacy?

A

High affinity and high efficacy

46
Q

Why do agonists have high efficacy?

A

They are able to cause a conformational change in the receptorwhereas regular drugs don’t necessarily cause any changes

47
Q

Describe some of the sources of drugs

A

Natural products from nature
Synthetic drugs from the pharmaceutical industry
Biotechnology using living systems to make therapeutic agents.
Gene therapy

48
Q

How do drugs act?

A

Interfering with a binding site - a receptor

49
Q

Give examples of binding sites

A

Cell surface and intracellular receptors
Ion channels
Carriers
Enzymes
Nucleic acids

50
Q

What is transmembrane signalling?

A

Recognition and binding of an extracellular signal by an integral membrane receptor protein and the generation of intracellular signals by one or more effector proteins.

Foundations of Medicine (56 decks)

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