Brainscape's Knowledge GenomeTM

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


See full index

DEN 2026 - Pharmacology > Receptor-Effector Coupling > Flashcards

Receptor-Effector Coupling Flashcards

1
Q

What are 2 biological approaches to receptor classification?

A
  1. Molecular structure

2. Signal transduction mechanism

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

What 3 things affect the molecular structure of receptor proteins?

A
  1. Amino acid sequence
  2. 2ry and 3ry structure
  3. Location of binding sites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What 3 things affect the signal transduction mechanism?

A
  1. Ion flux
  2. Enzyme activity
  3. Gene expression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How many super families of receptors are there?

A

4

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

Name the 4 receptor super families

A
  1. Ligand-gated ion channels
  2. G-protein-coupled receptors
  3. Kinase-linked receptors
  4. Nuclear receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the major differences between families 1-3 and family 4?

A

First 3 families are on cell surface whereas nuclear receptors are intracellular

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

What causes a group of receptors to become a superfamily?

A

Possess basic molecular and functional properties as each other but encoded by different genes which causes different shapes of receptors which respond to a specific mediator

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

What 2 substances stimulate superfamily 1 receptors?

A
  1. Acetylcholine

2. Nicotine (selectively)

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

Name 2 competitive reversible antagonists to superfamily 1 receptors

A
  1. Tubocurarine

2. Vecuronium

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

Name a non-competitive antagonist to superfamily 1 receptors

A

Lidocaine

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

What is the function of neuromuscular blocking agents such as tubocurarine?

A

Prevent skeletal muscle contraction during surgery

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

How does lidocaine act as a non-competitive antagonist to superfamily 1 receptors?

A

Antagonises the action of acetylcholine at some point in the chain

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

What are 3 characteristics of nicotinic cholinoceptors in neuromuscular junctions?

A
  • Receptor is made up of 5 sub-units
  • Primary amino acid sequence runs from N terminal to C terminal
  • 4 transmembrane helices allow sub-unit to move through membrane and be anchored
  • 2nd helix of each sub-unit comprise the channel pore
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is a nicotinic receptor activated?

A

A molecule of acetylcholine must bind to both a sub-units in the receptor

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

What are 3 characteristics of receptors in superfamily 2?

A
  • Single protein spans 7 times across membrane to anchor it
  • Extracellular N terminal binds to substances
  • Cytoplasmic and extracellular loops found between different parts of protein spanning membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are receptors in superfamily 2 coupled with?

A

Heterotrimeric G-proteins

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

What are 3 characteristics of a G-protein?

A
  1. Consist of 3 sub-units (alpha, beta, gamma)
  2. Molecular switches
  3. Communicate between superfamily 2 receptor and an effector
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What 3 sites are found on the a sub-unit of a G-protein?

A
  1. Receptor interaction site
  2. GTP binding site
  3. Target protein interaction site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the switching on and off of G-proteins

A
  • GTP binds to the a subunit which turns on G-protein
  • Intrinsic enzyme activity of GTPase breaks down GTP bound to sub-unit
  • GTP broken down to GDP which is released from a sub-unit as the reaction stops
20
Q

What is a second messenger?

A

Intracellular chemical, the concentration of which can be altered rapidly and reversibly on activation of a cell surface receptor, to regulate activity of an internal effector to produce intracellular response

21
Q

What are the 2 mechanisms which second messengers generally come about?

A
  1. G-protein activates ion channel which allows ion to accumulate
  2. G-protein activates enzymes which generate ions
22
Q

What can regulate concentration of ions acting as second messengers?

A

Internal effector

23
Q

What gives G-proteins specificity?

A

Different a sub-units are encoded by a different gene or splice variants

24
Q

How can G-proteins be stimulator or inhibitory?

A

Can induce a conformational change in effector protein to more or less active states

25
Q

Give 3 examples of effectors regulated by G-proteins

A
  1. Adenylate cyclase
  2. Phospholipase C-b
  3. Voltage-gated calcium/potassium channels
26
Q

Describe cyclic AMP signalling pathway

A
  • Noradrenaline or adrenaline activates G-protein
  • Enhanced binding of GTP activates G-protein
  • Interaction with adenylate cyclase which catalyses production of second messenger
  • Second messenger regulates cAMP-dependent protein kinase
  • Kinase catalyses protein phosphorylation to bring about cellular response
27
Q

Name 2 types of drugs and their function which target cyclic AMP signalling pathway

A
  1. β₁ adrenoceptors - Enhance cardiac muscle action

2. β₂ adrenoceptors - Bronchodilation

28
Q

What is an example of a β₁ adrenoceptor drug?

A

Dobutamine

29
Q

What is an example of a β₂ adrenoceptor drug?

A

Salbutamol

30
Q

Name an antagonist drug of β₁ adrenoceptors

A

Beta blockers e.g. atenolol

31
Q

What are 3 ways a cyclic AMP signalling pathway can be terminated?

A
  1. Breaking down the mediator
  2. Breaking down GTP
  3. Metabolism for cAMP in cytoplasm
32
Q

How is cAMP metabolised in cytoplasm?

A

Enzyme cyclic AMP phosphodiesterase hydrolyses across ring leading to linear molecules which does not activate kinase

33
Q

How does caffeine lead to a greater response of cyclic AMP signalling pathway?

A

Inhibits the action of cAMP phosphodiesterase

34
Q

What are 2 types of superfamily 3 receptors?

A
  1. Receptors directly linked to tyrosine kinase

2. Receptors directly linked to guanylate cyclase

35
Q

Name 4 receptors which are directly linked to tyrosine kinase

A
  1. Insulin
  2. Insulin-like growth factor
  3. Epidermal growth factor
  4. Cytokine
36
Q

Name 2 receptors which are directly linked to guanylate cyclase

A
  1. Natriuretic peptide

2. Guanylin

37
Q

What is the function of tyrosine kinase?

A

Phosphorylates tyrosine amino acids into proteins

38
Q

What is the function of guanylate cyclase?

A

Creates cyclic GNP

39
Q

Describe the 5 steps of activation and transduction of tyrosine kinase-linked receptors?

A
  • Ligand binds to receptor which causes conformational change in receptor
  • Dimer forms
  • Dimer formation increases enzyme activity
  • Enzyme phosphorylates tyrosine groups on adjacent molecule in the dimer
  • Dimer splits
40
Q

What is the function of SH-2 domain protein?

A

Recognize the phosphorylated amino acids in which phosphorylation helps binding of proteins to enzymes

41
Q

Give an example of a drug which targets tyrosine kinase-linked receptors

A

Herceptin

42
Q

How does herceptin slow tumour progress

A

Bind to proteins which prevents receptors from binding with growth factors and slowing tumour progress

43
Q

Name 3 types of receptors in uperfamily 4

A
  1. Receptors for lipophilic steroid hormones
  2. Receptors for lipid mediator present in cells
  3. Receptors for lipophilic vitamins
44
Q

Describe the mechanism of action of superfamily 4 receptors

A
  • Agonist binds to intracellular receptors
  • Zinc finger domain opens and binds to hormone responsive elements
  • Activity of RNA polymerase, gene transcription and translation of mRNA is affected
  • This allows synthesis of new proteins and altered cellular reponse
45
Q

Name 2 type of nuclear receptor therapeutics

A
  1. Aldosterone receptor antagonists e.g. spironolactone

2. Corticosteroid receptor agonists e.g. budesonide

DEN 2026 - Pharmacology (22 decks)

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