Structure Of Receptors Flashcards

1
Q

Define receptor

A

A molecule that specifically recognises a second molecule (ligand) or family of molecules and which is in response to ligand binding, brings about a cellular response.

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2
Q

What is the difference between receptors and acceptors?

A

Receptors are functionally silent when unbound. Acceptors still contributes to the cellular process when unbound and only modulate their behaviour when bound.

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3
Q

What is Kd?

A

The concentration of ligand that fills half the receptor sites

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4
Q

How many types of muscarinic receptor are there?

A

5

M1-M5

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5
Q

Name 3 receptors with an integral ion channel

A

nAChR
GABA receptors
IP3 receptors

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6
Q

Describe the structure of nAChR

A

Pentameric (5 subunits)
Channel in the centre of the subunits
2 alpha subunits that bind ACh to open

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7
Q

In ‘classical’ ligand gated ion channels, where is the N terminus?

A

On the outside of the cell

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8
Q

Name 2 non-classical LG ion channels

A

ATP sensitive K+ channel

Ryanodine receptors

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9
Q

Name 4 receptors with integral enzyme activity

A

ANP receptor (cardiac)
Insulin receptor
EGF receptor
PDGF receptor

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10
Q

Which receptors are linked directly to tyrosine kinase?

A

Insulin receptor
EGF receptor
PDGF receptor

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11
Q

What are SH2 domains?

A

Phospho recognition sites

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12
Q

What is another name for GPCRs?

A

7 TMD receptors

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13
Q

What is the brief, general pathway when adrenaline binds to beta adrenoceptors?

A

G alpha s activated

Activates adenylyl cyclase to produce more cAMP

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14
Q

What is the brief, general pathway when ACh binds to M2 receptors?

A

G alpha i subunit activated

Stimulates K+ channel opening

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15
Q

How are the DNA binding domains of intracellular receptors sometimes described?

A

Zinc fingers

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16
Q

What stops the intracellular receptor binding to DNA at rest?

A

The DNA binding domain is blocked by an inhibitory protein

17
Q

Noradrenaline acts on which receptors in the heart to increase HR?

A

Beta 1 adrenoceptors

18
Q

ACh acts on which receptors in the heart to decrease HR?

A

M2 muscarinic receptors

19
Q

What are the 3 basic types of signalling molecules?

A

Local mediators
Hormones
Neurotransmitters

20
Q

Define affinity

A

The measure of the ability of a drug (ligand) to form a drug-receptor complex

21
Q

Define efficacy

A

The measure of the ability of the drug-receptor complex to produce a response

22
Q

If the dose response curved is higher, it has a greater …

A

Efficacy

23
Q

If the dose response curve is to the left it has a greater…

A

Potency

24
Q

Define tachyphylaxis

A

Excessive exposure to agonist causes reduced sensitivity due to receptor down-regulation

25
Q

Define suprasensitivity

A

Upregulation of receptors due to agonist deprivation or excessive antagonist exposure

26
Q

What are the effects of opioids?

A

Analgesia
Sedation
Euphoria

27
Q

Where are SERMs agonists?

A

Bone and uterus

28
Q

Why aren’t receptors down regulated in patients with a pheochromocytoma?

A

The secretions of adrenaline and NA are intermittent

Symptoms actually worsen over time