1 - Receptor Families and Ligands Flashcards Preview

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Flashcards in 1 - Receptor Families and Ligands Deck (21)
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1
Q

What is pharmacokinetics and pharmacodynamics?

A

Pharmacokinetics - What the body does to the drug

Pharmacodynamics - What the drug does to the body?

2
Q

What are the four types of ways cells signal to one another?

A
3
Q

What is autocrine signalling?

A

A cell secretes a ligand, which then acts on a receptor on the same cell that secreted the ligand

4
Q

What is a receptor and a ligand?

A

Receptor: A molecule that recognises a ligand and in response to ligand binding, brings about a regulation of a cellular process

Ligand: A molecule that binds to a specific receptor

5
Q

What is an agonist and antagonist?

A

Agonist: A ligand that when bound to a receptor, activates the receptor, so it begins regulating a cellular process.

Antagonist: A ligand that binds to a receptor but cannot acitvate it

6
Q

What are the roles of receptors?

A
  • Signalling
  • Modulating immune response
  • Releasing intracellular calcium stores
  • Neurotransmission
  • Cellular delivery
  • Cell adhesion
  • Control gene expression
7
Q

What is the affinity (Km) of a receptor?

A

]

The concentration of ligand needed to fill half the receptor sites.

(Higher than Km of substrate/enzymes)

TIGHT BUT REVERSIBLE

8
Q

How are receptors classified?

A

1st - Agonist that binds to them

2nd - The antagonist that has the highest affinity

9
Q

What type of molecules bind to nuclear receptors?

A

Small hydrophobic, e,g sex and steroid

10
Q

What is an acceptor?

A

Still operates in absence of a ligand

11
Q

What are the four receptor nuclear families in order of fastest to slowest?

A
  • LGIC
  • Catalytic
  • GPCR
  • Nuclear
12
Q

What is the structure of a classical LGIC and how does it work?

A

Ligand binds allosterically to receptor, causing a conformational change. This opens the gated pore so ions can diffuse in

13
Q

What is the structure of a GPCR and how does it work?

A
  1. Ligand binds causing change in shape of receptor, activating it so has higher affinity for G protein
  2. G protein binds, causes change so changes affinity for GDP so GDP disassociates and GTP associates
  3. A-GTP subunit dissociates and goes on to activate transducers by phosphorylation
14
Q

What is the structure of a catalytic (TK) receptor and how does it work?

A
  1. Agonist binds to ligand binding domain
  2. Dimerisation of receptors
  3. Autophosphorylation
  4. YP can then phosphorylate enzymes and transducers, activating them
15
Q

Why is the insulin receptor different to the normal catalytic receptors?

A

Made up of 4 proteins not 2

16
Q

If an agonist is bound to a receptor, why can there be no change in the regulation of a cellular process?

A
  • Receptor is an inhibitory cellular process
  • Integrated signalling
17
Q

What is the structure of an intracellular receptor and how does it work?

A
  1. Ligand binds to LBD, changes shape of it so releases inhibitory protein
  2. DBD free to bind to DNA and regulate transcription
18
Q

Name a few ligands for each receptor family.

A
  • GPCR - Adrenaline, Acetylcholine
  • LGIC - Nicotine, IP3
  • Catalytic - Insulin, GF’s
  • Nuclear - Oestrogen, Cortisol, Vit D, Thyroid Hormone
19
Q

Name a type of receptors for each receptor family

A
  • LGIC - Nicotinic Acetylcholine
  • GPCR - Muscarinic Acetlycholine
  • Catalytic - Tyrosine Kinase
  • Nuclear - Oestrogen
20
Q

What are some examples of agonists and antagonists?

A

Agonist:

  • Asthma: Salmeterol/Salbutamol. B2 adrenoreceptor and cause bronchodilation
  • Analgesia: Morphine, U opiod

Antagonist

  • Anti-hypertensives (Atenolol): B1 adrenoreceptors, block intropy of heart, decreasing b.p
  • Haloperidol: D2 Dopamine, neuroleptic
21
Q

Why is signal amplification important?

A

Converts nanomolar signals to millimolar responses

  • Speed
  • Multiple pathways triggered