Equations

Question 1

What does the Hill equation show?

Answer 1

it describes the relationship between the partial pressure of oxygen and the oxygen saturation of hemoglobin.
It is used to describe the fraction of a macromolecule saturated by ligand as a function of the ligand concentration.

Question 2

What is Ehrlich’s Therapeutic Index?

Answer 2

TI = (max non toxic dose)/(min effective dose)
or TI = (Toxic dose 50%)/(Effective dose 50%)
animal studies:
TI = (lethal dose 50%)/(effective dose 50%)

Question 3

What is the Hill Langmuir equation?

Answer 3

PAR = (A) / (Ka + A)

Question 4

What is the equation of the Hill plot?

Answer 4

log ( Par / (1-Par) = log (A) - log (Ka)
log ( Par / (1-Par) against log (A) gives a straight line, slope 1.
In practice, the Hill slope is not always constant, and is referred to as nH, the Hill coefficient.

Question 5

What is the Hill equation?

Answer 5

y = ymax (A^nH) / (EC50 ^ nH + A^nH)
nH is the Hill coefficient. y is the observed response, ymax is the max response to a large concentration of agonist. EC50 is the concentration of A at which y is half maximal.

Question 6

What is an equation relating efficacy and intrinsic efficacy?

Answer 6

e = epsilon [R]T

epsilon is intrinsic efficacy (the max response to agonist/max response to full agonist at same receptor)

Question 7

What is the del Castillo & Katz model?

Answer 7

They introduced the idea of an occupied inactive receptor and occupied active receptor with equilibrium constant E.

Question 8

What is the Gaddum equation?

Answer 8

PAR = [A] / (Ka (1 + [B]/Kb) + [A])

Question 9

What is the Schild equation?

Answer 9

r -1 = [B] / Kb

r is the concentration ratio

Question 10

What is pA2?

Answer 10

empirical measure of activity of antagonist

pA2 = -log [B] (r=2)