Flashcards in Pharmacodynamics Deck (21):
what are the features of drug receptors?
1. recognize and bind other molecules (ligands)
2. propagate regulatory signals following ligand binding
3. modulate ongoing cellular functions
estrogen receptor and vitamin A receptor are what types of receptors?
what are two examples of intracellular receptors?
estrogen and vitamin A
EGFR, IR, and TGF-BR are what types of receptors?
intrinsic enzymatic activity
what are the typical targets for receptors with intrinsic enzymatic activity?
signal transduction - protein and lipid kinase cascades, protein phosphatases
what are examples of receptors with intrinsic activity?
EGFR, IR, TGF-BR
nicotinic Ach receptor is what type of receptor?
ligand gated ion channel
IL-3r, EPOr, and leptin receptor are what type of receptors?
directly associate with intracellular enzymes
which receptors directly associate with intracellular enzymes?
IL-3r, EPOr, and leptin receptor
B-adrenergic, rhodopsin, frizzled, and Smo receptors are what type of receptors?
what is the dissociation constant for drug binding affinity?
Kd = [R][L] / [RL]
or, Koff / Kon
what is the dissociation constant Kd equal to when the free receptor concentration equals the concentration of bound receptor?
ligand concentration (when half the receptors are occupied and half are free)
how does a small Kd value relate to binding affinity?
small Kd = greater binding affinity
measurement of drug dose used to compare the relative affinity and effectiveness of two or more drugs - done by comparing EC50s (more potent = more to the left)
the maximal effect a drug can induce
definition: competitive antagonist
1. agonist and antagonist compete for same binding site
2. shift to the right in the EC50
3. maximal effect is still achievable
definition: noncompetitive antagonist
1. agonist and antagonist bind to different sites
2. decrease in maximal effect
3. agonist's affinity for receptor may not change in presence of noncompetitive antagonist
definition: partial agonist
drug that produces a lower maximal response as compared to the agonist
definition: therapeutic index
2. ratio of TD50 / ED50
3. the greater the ratio / window between the TD50 and ED50, the safer the drug is for a patient
how does tolerance affect the dose-response curve?
shift to right