Drug-receptor interactions

Question 1

4 main targets fro drug action?

Answer 1

Enzymes
Receptors
Carriers
Ion channels

Question 2

How to agonists and antagonists work with receptors?

Answer 2

Agonists activate the receptors

Antagonists block the action of the agonist

Question 3

What type of molecule is histamine with respect to receptors and what is its action?

Answer 3

H1 agonist

Vasodilation to increase blood flow to smooth muscles

Question 4

How can receptor subtypes be identified?

Answer 4

Selectivity fo agonist or antagonist

Cloning techniques

Question 5

How do subtypes differ?

Answer 5

Similar structure but different pharmacological properties

Different mechanism of activation, transduction, inhibition

Question 6

Name 4 types of receptors that transduce the signal

Answer 6

LIgand gated/voltage gated
G coupled
Enzyme linked
Intracellular

Question 7

How do ligand gated ion channels transduce the signal?

Answer 7

Channel is linked to a receptor

Agonist is required to bind to open the receptor

Question 8

How do voltage gated ion channels differ to ligand gated?

Answer 8

Voltage gated are not linked to receptors, only require a change in membrane potential to open or close

Question 9

Which subunit of the g coupled receptor varies to cause specificity?

Answer 9

Alpha

Question 10

Name 4 types of G coupled receptors

Answer 10

Gs = stimulatory (activate adenylyl cyclase)
Gi = inhibitory (inhibits adenylyl cyclase)
Gq = activates phospholipase C
Go = doesn't interact with alpha - lets beta and gamma do the work

Question 11

Describe the action of a Gs coupled receptor

Answer 11

When no ligand bond receptor doesn’t interact with G protein, G protein binds GDP
When ligand binds = conformation change to receptor - it interacts with G protein and G protein dissociated GDP and bind GDP
The activates adenylyl cyclase
Converts ATP to cAMP = second messenger

Question 12

Name a type of G-coupled receptor

What activates them?

Answer 12

Adrenergic receptor

Adrenaline or noradrenaline

Question 13

What type of alpha subunit does each adrenergic subtype have? How does this relate to function?

Answer 13

Alpha 1 = Gq = activate phospholipase C = vasoconstriction
Alpha 2 = Gi = inhibit adenylyl cyclase = auto-inhibition of neurotransmitter release
Beta 1 and 2 = Gs = increase heart rate and bronchodilator

Question 14

What is the effect of activating phospholipase C?

Answer 14

Vasoconstriction

Question 15

Effect of inhibiting adenylyl cyclase

Answer 15

No cAMP = no signal transduction = auto-inhibition of neurotransmitter release

Question 16

Effect of stimulating adenylyl cyclase

Answer 16

cAMP = tranduction

Sympathetic response = increase heart rate and bronchodilation

Question 17

Structure of enzyme linked receptor

Answer 17

Large ligand binding domain connected to intracellular domain

Question 18

3 steps enzyme linked receptors follow?

Answer 18

Ligand binding
Dimerisation
Auto-phosphorylation

Question 19

How does tyrosine kinase receptor work with insulin?

Answer 19

Insulin binds causing conformation change dimerisation) and activates tyrosine kinase which phsophorylates kinase and IRS = activating pathways to lower blood glucose

Question 20

2 classes of intracellular receptors

Answer 20

Class I = in cytoplasm

Class II = in nucleus

Question 21

Difference between class I and II intracellular receptors other than location?

Answer 21

Class I increases product of receptor

Class II increases physiological effects

Question 22

Underlying mechanism for intracellular receptors?

Answer 22

Ligand binding induces gene transcription changes