Pharmacodynamics definitions Flashcards
(34 cards)
metric prefix subdivision in order of siza
molar –> millimolar –>. micromolar –> nanomolar –> picomolar
Log10 of number
power by which 10 has to be raised to get that number
what is the log number of 1000
10 x 10 x 10 = 10^3 log1000= 3
Log10 of 0.000001m
Log10^ -6
A ligand =
a substance that can interact with a target protein or receptor • Binds to specific site on that signalling protein • Ligands can endogenous (hormones, ions or NT) or exogenous
An agonist=
a substance which binds to a receptor and activates the receptor to then produce a measurable biological response
An antagonist=
a substance which binds to a receptor, but does not produce a biological response • block the effects of agonists
Affinity=
is a measure of the strength of which a ligand or drug binds to a receptor
What is the measurement used to define affinity?
Affinity is measured by Kd
Kd=
the concentration of ligand at which 50% of all available receptors are bound • lower the value of Kd the greater affinity
Intrinsic efficacy=
A term used to describe the ability of a ligand to generate the active form of the receptor (R*- active form of receptor)
agonist has
intrinsic efficacy and affinity
antagonist has
affinity but no intrinsic efficacy
Ligand efficacy=
ability to cause a measurable biological response
Clinical efficacy=
relates to response with therapeutic value e.g, does the drug reduce blood pressure
Agonist potency=
the concentration of a drug that evokes 50% of its maximal response (Emax) -The term EC50 is used to represent this concentration
The smaller the EC50
- the higher the potency of the drug
Partial agonist=
ligands that evoke responses that are lower than the maximal response of the full agonist (i.e they have lower Emax values)
Compared to a full agonist, a partial agonist has
lower intrinsic efficacy • Partial agonists have a lesser ability to activate the receptor • Therefore doesnt evoke the maximal biological response
which drug has the highest intrnsic activity?

B
Which drug has the highest potency?

A
measuremnts used in the binding curves
Kd and Bmax
concentration-response curve measurements
EC50 and Emax
Bmax
the maximum amount of drug/luigand which can bind to the receptor
-can be used to measure the density of the receptor site in a particular tissue e.g. fluorescent tagging

