L5 - Measurement of drug action at receptors

Question 1

What method is used to measure the affinity of a drug?

Answer 1

Radioligand binding assays

Question 2

What can measure the affinity of an antagonist for the receptor by creating a shift in the agonist curve?

Answer 2

Dose-ratio

Question 3

What is used to quantified the affinity of a competitive antagonist?

Answer 3

pA2

Question 4

Whats pA2?

Answer 4

It is the negative logarithm of the MOLAR concentration of antagonist that necessitates that you can double the agonist concentration to produce the same response (i.e. dose ratio = 2.0)

Question 5

Schild equation

Answer 5

log(dose ratio - 1) = log(antagonist concentration) - logKB

Question 6

What is KB?

Answer 6

It is the dissociation equilibrium constant for an antagonist measure using schild equation

Question 7

What are the x-axis and y-axis of a reversible competitive antagonist for a Schild plot?

Answer 7

x-axis = log antagonist concentration
y-axis = log (dose ratio - 1)

Question 8

In Schild plot, ______ = pKB = -logKB

Answer 8

pA2

Question 9

How do you find logKB?

Answer 9

log KB is where the slope intersect at the x-axis of the Schild plot

Question 10

If the slope of the Schild plot does not equal to 1.0 (0.8 - 1.2),

Answer 10

the antagonist is not competitive or irreversible

Question 11

The formula for dose ratio

Answer 11

EC50 in presence of antagonist / EC50 in absence of antagonist