Brainscape's Knowledge GenomeTM

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


See full index

PHAY0003 > Mechanism of Drug Action > Flashcards

Mechanism of Drug Action Flashcards

1
Q

Where is the GABAa receptor found?

A

On neurons in the amygdala and hypothalamus in the brain

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

What type of receptor is GABAa?

A

Ligand-gated ion channel for Cl- ions

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

What amino acids are the M2 helix of GABA rich in?

A

Positive amino acids, arg and lys

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

What effect does GABA have when binding to GABAa and why?

A

Sedative effect, when it binds, Cl- ions flow into the cell, hyperpolarizing the membrane making the neuron less likely to fire an action potential

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

What class of drugs also bind to GABAa and what is their indication?

A

Benzodiazepines e.g diazepan (Valium)

Short term treatment of anxiety

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

How do benzodiazepines help with anxiety?

A

They enhance the effect of GABA binding to GABAa

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

What also enhances the binding of GABA to GABAa receptors resulting in a sedative effect as well as benzodiazepines?

A

Alcohol

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

What is the role of oestrogen?

A

To control when cells grow

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

Give an example of when oestrogen is beneficial and when it can be harmful

A

It is important for bone growth and prevents osteoporosis

It an also enhance the unnatural growth of tumours

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

What drug is used to treat cancer through blocking oestrogen?

A

Tamoxifen

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

Describe how tamoxifen works for treatment of cancer

A

It mimics the shape of oestrogen and binds tightly to the oestrogen receptor, changing the shape of the signalling loop, preventing the binding of transactivation proteins and RNA polymerase

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

What type of receptor is oestrogen receptor?

A

DNA-binding receptor

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

How are tyrosine kinase receptors linked to cancer and give an example?

A

In cancer cells, mutated tyrosine kinases are over active leading to more transcription and therefore excessive growth
E.g Leukaemia

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

Describe the mutation in cancerous tyrosine kinase receptors

A

There is a translocation mutation of one of the genes resulting in the loss of the region which codes the the regulatory region for ligand binding resulting in the receptor always being in the active form, Bcr-Abl kinase

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

What is Bcr-Abl tyrosine kinase?

A

The mutated form of tyrosine kinase which is always in the active form and results in excessive growth

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

What drug is used aginst Bcr-Abl tyrosine kinase?

A

Imatinib (Gleevec), 90% of patients respond well to it

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

Describe how Gleevec works against Bcr-Abl tyrosine kinase

A

It mimics ATP and binds to the ATP site on the binding site in the c terminus, blocking the binding of ATP and phosphorylation and no binding site for proteins is exposed and so no transcription of proteins

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

What type of receptors do beta-blockers target?

A

GPCRs

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

Which domains of GPCRs are most important in binding to adrenaline?

A

M3, M6, M5

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

What type of ligands are beta blockers?

A

Antagonists

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

Give 2 examples of beta-blockers

A

Propranolol, atenolol

22
Q

How do beta-blockers work?

A

They mimic the shape of adrenaline and bind to the the pocket in the receptor but do not activate the receptor and so block the following processes that normally happen that lead to heart contraction

23
Q

How were beta-blocker drugs synthesised?

A

By chemical modification of adrenaline

24
Q

Which 3 regions on adrenaline are also found in beta-blockers?

A

Benzene ring, OH and NH

25
Q

When are beta-blockers more effective?

A

During exercise, stress or excitement since they block pathways stimulated by adrenaline

26
Q

What class of drugs lower lipid levels in the blood?

A

Fibrates

27
Q

How do fibrates reduce the lipid levels in the blood?

A

They reduce the concentration of VLDL which contains triacylglycerols by rapidly increasing the number (proliferate) of peroxisomes in a cell

28
Q

Give an example of a fibrate

A

Clofibrate

29
Q

What receptors do fibrates bind to?

A

PPARs (peroxisome proliferator activated receptors)

30
Q

What are PPARs?

A

Peroxisome proliferated activated receptors, they are nuclear receptors that are also specific transcription factors

31
Q

Describe the mechanism of fibrates binding to PPARs

A

Fibrates bind to the PPARa isoform causing a conformational change which promotes dimerisation with RXR. This complex binds to PPARa Response Element (PPRE) in the promoter region of the target gene. This complex then recruits the TFs (e.g TFIID) and RNA polymerase II to activate transcription of the target gene

32
Q

What in target genes that contain PPRE makes them effective at lowering lipid levels?

A

They contain genes that encode for proteins that remove VLDL triacylglycerol from the plasma and destroy it by oxidation

33
Q

Which part of the protein structure on an antibody contains the binding site for the antigen?

A

Tertiary structure, at the tips of the heavy and light chains

34
Q

What are the 2 major therapeutic uses of antibodies?

A

Vaccines and monoclonal antibodies

35
Q

What is an attenuated vaccine?

A

A vaccine that contains a weakened version of the virus/bacteria which cannot cause disease

36
Q

What is an inactivated vaccine?

A

A vaccine that contains dead virus

37
Q

What are subunit vaccines?

A

Vaccines that only use one viral/bacterial protein (purified pathogen)

38
Q

Describe the general idea behind vaccines

A

When injected, the body begins to make B-lymphocytes which are specific to the antigen, after a few doses, the body contains a sufficient supply of “memory” B-lymphocytes so that a future immune response is faster

39
Q

Describe the mechanism behind the Covid vaccine

A

One of the transmembrane proteins on SARS-Cov-2 is S1, this protein binds to ACE2 using RBD in humans to initiate a response. Antibodies that are produced in response to the vaccine bind to this same protein, inhibiting RBD from binding to ACE2

40
Q

How are antibodies produced in scientific research?

A

Repeated immunisation of a suitable animal, their blood is then taken and a serum is prepared the the peak of antibody production

41
Q

What is the epitope?

A

The region on the antigen which is recognised by antibodies

42
Q

What is the difference between polyclonal and monoclonal antibodies?

A

Polyclonal antibodies are released from different B-cells but attach to the same antigen if the antigen is large and has different epitopes
Monoclonal antibodies are released from one B-cell and attach to the only epitope on an antigen

43
Q

Which gene is a key factor in breast cancer?

A

HER2 gene (human epidermal growth factor receptor 2 gene), over expression by tumour cells was found in patients with breast cancer

44
Q

What type of receptor is HER2

A

Tyrosine kinase

45
Q

What is the role of HER2?

A

It transmits the epidermal growth factor extracellular signal that controls cell growth and division

46
Q

What causes overexpression of HER2?

A

Gene amplification, more copies of the gene for HER2 are found in a tumour cell resulting in more transcription and synthesis of the receptors

47
Q

What is Herceptin?

A

A monoclonal antibody that was produced using a mouse B cell where 95% of it was genetically engineered to look like a human cell to reduce chances of rejection

48
Q

How are monoclonal antibodies synthesised in a lab?

A

They are produced by cells obtained from immunised animals

49
Q

Describe how Herceptin works

A

It reacts with cancer cells that have increased HER2 on their surface by binding to the receptor resulting in the growth signals normally released to be prevented i.e through EGFs

50
Q

What is the ADCC mechanism

A

Antibody-dependent cellular cytotoxicity, the immune system destroys cells that are labelled with antibodies

PHAY0003 (22 decks)

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