Receptor Characterisation

Question 1

Testing new drugs: Ligand-receptor binding Assay. What is it give details? (6)

Answer 1

Radioactive drug binds to specific and non specific sites
Increasing conc of raioactive drug suturates specific sites
Radioligand binding measurement of whether a drug interacts with a specific receptor

Affinity: how sticky how much we need to give for it to bind, ability of a drug and receptor to form a drug receptor complex
Inversly proportional to equilirbrium constant
Higher K=lower affinity and vice versa

Lower K=higher affinity
K: dissociation
Affinity: association

Question 2

What are the 4 new types of ligand binding assay?

Answer 2

Flourescence Resonance energy transfer FRET
Surface Plasmon Resonance SPR
Immunoprecipitation IP
Positron Emission Tomography PET

Question 3

What is FRET?

Answer 3

DONOR MOLECULE (DRUG) AND GIVE IT TO THE ACCEPTOR (RECEPTOR), WHEN DRUG COME CLOSER TO THE RECEPTOR —> IT WILL INCREASE FLOURESENCE, THE CLOSER IT IS THE MORE FLOURESENCE

Question 4

What is SPR?

Answer 4

take receptors fix them onto a metal surface, on the other side there is a glass prism, the more binding of receptor-drug complexes, the light refracts (PHYSISCS IDK??!

Question 5

What is IP?

Answer 5

link drug to a Ab or receptor put in solution and then pull out the Ab and perform a regular western blot etc to see if the drug is still there

Question 6

What is PET?

Answer 6

Fluorescent marker, probably the best method out of the 4, in vivo imaging
We can see where exactly the receptor is the darker (red the colour the more of the receptor is present

Question 7

True or False?
The relationship between binding (affinity) and response (efficacy) is not always linear?

Answer 7

True

Question 8

Binding vs. Response
Whats the hypothesis that drug response receptor binded but response low for partial agonists?

Answer 8

There are spare receptors not all receptors will give a full response when bound.

Question 9

What are 5 receptor changes?

Answer 9

Number of receptors
Location of receptors
Receptor mutants
Efficiency of coupling
Exhaustion of mediators

Question 10

What is receptor de-sensitisation?

Answer 10

Effect of drug gradually diminishes when it is given continuously or repeatedly

Question 11

What are orphan receptors?

Answer 11

Receptors identified but not their endogenous ligand
Huge potential for new therapies