PHARMACODYNAMICS Flashcards
The cellular macromolecule or macromolecule
complex with which the drug interacts to elicit a
cellular response
DRUG RECEPTOR/ DRUG TARGET
Other receptors can be in the form of
ion
channels, Enzymes and Transporters.
Binding of ATENOLOL to Beta receptor
stimulates conversion of _______ (producing
biologic effects by the activation of G-protein)
ATP to cAMP
Ex: Binding of amlodipine to calcium channel
Ion channels
_____ block NaCl transporter at the distal convoluted tubule
Thiazides
Magnitude of biologic effect is directly related to the fraction of ACTIVE STATE
Partial agonist
In reversible equilibrium, it favors more the
_____state.
inactive
Drugs that bind to physiological receptors and
mimic the regulatory effects of the endogenous
signalling compounds/ endogenous ligand.
AGONIST
Are drugs that would bind on the same
recognition site as the endogenous
ligand/agonist.
PRIMARY AGONIST
Drug binds to a different site but produces the
same effect as that of the endogenous ligand.
ALLOSTERIC/ ALLOTOPIC AGONIST
Transduction process that links drug occupancy
of receptors and pharmacological response
Coupling
After drug-receptor binding, _____
may occur then cause _____,
desensitization and down-regulation of the
receptor.
signal transduction; signal amplification
Signal amplification is only seen if the mechanism involves ______ and ______
second
messenger G-protein coupled receptors ;
enzyme-linked receptors.
Binding of ____(Beta agonist) to its
receptor would activate the receptor → Stimulates
G-protein coupled receptors (aka 7
Transmembrane receptors because it is a
protein located at the cell membrane; it passes
through it for about 7 times. It contains Alpha,
Beta and Gamma.)
Albuterol
3 TYPES OF G-PROTEIN COUPLED RECEPTORS
Gs/ STIMULATORY
Gi/ INHIBITORY
Gq
Gs/ STIMULATORY ideally binds to ____
GDP
Spare receptor is also seen by the mechanism of ____
signal amplification
Half occupancy of the receptor produces
EC50
is the concentration of a drug that
produces 50% of maximal effect.
EC 50
- concentration of free drug at which ½
maximal binding is observed
Kd/Equilibrium Constant-
EC50 is LESS THAN Kd
(+) SPARE RECEPTORS:
EC50 is EQUAL TO Kd
(-) SPARE RECEPTORS
Repeated or continuous administration of an
agonist (or antagonist) may lead to changes in
the responsiveness of the receptor
DESENSITIZATION AND DOWN-REGULATION OF
RECEPTORS
Phosphorylation or a similar chemical event that
renders a receptor on that cell surface
unresponsive to the ligand
TAPHYLAXIS
How can you overcome the effect of your competitive antagonist?
increase the amount of agonist
affinity of one for the other
dissociation constant
Concentration-effect curve can be expressed as ____ curve
Hyperbolic curve
Effect of B1 receptors in the heart
Increase heart rate
maximal response that can be produced by the drug
Emax
concentration of a free drug in which half maximal binding is observed
Kd
100 ligands bound to 100 receptors
Bmax
T or false
Kd=Ec50
False
Ec50=effect; Kd=___
Binding of the receptors
refers to concentration or dose of a drug required to produce 50% of that drug’s maximal effect
Potency
Lower ED50=___potency
high
T or F
You can compare potency of drugs with different effects
False
