PRELIM 03 - Pharmacodynamics Flashcards
Refers to the cellular macromolecule or macromolecular complex with which the drug interacts to elicit a cellular or systemic response
Receptor/Drug targets
Refers to the ability to bind to receptors
Affinity
Refers to the ability to activate receptors and generate a response
Efficacy/Intrinsic activity
Refers to the amount of drug needed to produce an effect; affected by both affinity and efficacy
Potency
Refers to the ability to distinguish between receptors
Specificity
Tissue response is proportional to number of receptors occupied; by Clark and Gadum (Theories of drug receptor interaction)
Occupancy theory
Retains the assumption that tissue response is proportional to number of receptors occupied; by Ariens and Stephenson (Theories of drug receptor interaction)
Modified occupancy theory
Drug receptor interaction effect is proportional to the rate of drug receptor combination; by Croxatto and Paton (Theories of drug receptor interaction)
Rate theory
According to the rate theory, __________ has a high rate of association and dissociation
Agonist
According to the rate theory, __________ has a high rate of association and low rate of dissociation
Antagonist
Combination of ligand and receptor produces a change in conformation of the receptor; by Koshland (Theories of drug receptor interaction)
Induced fit theory
Interaction of small molecules (drug) with macromolecule (receptor) results in SCP and NSCP; by Belleau (Theories of drug receptor interaction)
Macromolecular perturbation theory
According to the macromolecular perturbation theory, the _________ has an agonist effect
Specific conformational perturbation (SCP)
According to the macromolecular perturbation theory, the __________ has an antagonist effect
Nonspecific conformational perturbation (NSCP)
Proposes that when a ligand binds, this results in a change in receptor stage from inactive to active; by Black and Leff (Theories of drug receptor interaction)
Two-state receptor theory
Uses equilibrium dissociation constants for the interactions between the receptor and each ligand; by De lean et al. (Theories of drug receptor interaction)
Ternary complex model
According to the ternary complex model, the __________ factor denotes the mutual effect of the two ligands on each other’s affinity for the receptor
Cooperativity
__________ activity indicates the production of physiologic effect without the drug
Constitutive
2 receptor states (AI)
Active (Ra), Inactive (Ri)
Intrinsic activity is 1; Maximal shift to Ra (Characteristic of drug effect)
Agonist
Intrinsic activity is >0 and <1; Partial shift to Ra (Characteristic of drug effect)
Partial agonist
Intrinsic activity is 0; No effect on equilibrium (Characteristic of drug effect)
Antagonist
Intrinsic activity is <0; Shift to Ri (Characteristic of drug effect)
Inverse agonist
Prevents activation of receptor by agonist; may be competitive or noncompetitive (Types of antagonist)
Receptor antagonist
Opposes effects of agonist through a different receptor (Types of antagonist)
Physiologic antagonist
Renders a substance inactive by binding to it (Types of antagonist)
Chemical antagonist
Structurally similar to agonist, binds reversibly to the same site of agonist; can be overcome by increasing agonist concentration (Types of receptor antagonist)
Competitive antagonist
Cannot be overcome by increasing agonist concentration (Types of receptor antagonist)
Noncompetitive antagonist
Binds irreversibly (covalently) to the same site of agonist (Types of noncompetitive antagonist)
Irreversible antagonist
Binds to a different site (allosteric site) from the site of the agonist (Types of noncompetitive antagonist)
Allosteric inhibitor
Refers to the conversion of a signal carried by a chemical messenger into an intracellular response
Signal transduction
Channels that allow passive diffusion of ions down electrochemical gradients across the cell membrane
Ion channels
Action potential across the cell membrane causes conformational change in the channel that opens or closes the gate (Types of ion channels)
Voltage-gated channels
Binding of a chemical substance (a ligand) with the channel causes conformational in the channel that opens or closes the gate (Types of ion channels)
Ligand-gated channels
3 components of G protein-coupled receptor (GEH)
G protein, Effector enzyme, Heptahelical receptor
The largest and most diverse group of receptors
G protein-coupled receptor (GPCR)
Meaning of G protein
Guanosine-nucleotide binding protein
3 subunits of G protein (ABG)
Alpha (α), Beta (β), Gamma (γ)
cAMP, DAG, IP3, and Ca2+ are all examples of __________
2° messengers
Are enzymes that phosphorylates proteins
Receptor protein kinases
Are enzymes that binds kinases which can phosphorylate proteins
Receptor bind protein kinases
An example of receptor protein kinase that has intrinsic tyrosine kinase activity
Receptor tyrosine kinase
Signal transducer protein of receptor tyrosine kinase
Grb2
__________ is a guanine nucleotide exchange factor (GEF) for Ras
Son of sevenless (SOS)
SOS is a GEF for __________, a monomeric G protein located in the plasma membrane
Ras
__________ is a serine protein kinase that is also called MAPKKK (Mitogen activated protein kinase kinase kinase)
Raf
_________ is a factor that allows exchange of GDP for GTP; involved in activation
Guanine nucleotide exchange factor (GEF)
________ are proteins that increase GTPase activity of G proteins or Ras; involved in inactivation
GTPase activating proteins (GAP)
An example of receptor protein kinase that has intrinsic serine/threonine kinase activity
Receptor serine/threonine kinase
Signal transducer protein of receptor serine/threonine kinase
Smad
An example of receptor bind protein kinase that binds with JAK (Janus kinase), an example of tyrosine kinase
Cytokine receptor/JAK-STAT receptor
Signal transducer protein of cytokine receptor/JAK-STAT receptor
Signal transducer and activator of transcription (STAT)
A receptor enzyme that has intrinsic guanylyl cyclase activity
Receptor guanylyl cylase
2 kinds of receptor guanylyl cyclase (MS)
Membrane-bound, Soluble
2° messenger of receptor guanylyl cyclase
cGMP
Signal cascade of receptor guanylyl cyclase
PKG
__________ receptors are used for hydrophobic drugs
Intracellular
2 kinds of intracellular receptors (CN)
Cytosolic, Nuclear
Signal cascade of intracellular receptors
Response element
Refers to the ability of receptors to amplify signal duration and intensity
Signal amplification
Response may be __________ or __________ (NG)
Non-genomic, Genomic
E.g. ion influx/efflux, alteration of protein activity; is usually immediate and brief (Types of response)
Non-genomic
E.g. gene expression; usually delayed and prolonged (Types of response)
Genomic
Refers to a decrease in response to a drug due to continued stimulation of receptors with agonists
Desensitization
Refers to a rapid desensitization
Tachyphylaxis
Happens due to endocytosis of receptors and sequestration inside cells
Downregulation
A plot of the degree of a given response against the plasma concentration/dose of the drug
Graded-dose response curve
A measure of the amount of drug necessary to produce an effect
Potency
A measure of the ability of the drug to elicit a response when it interacts with a receptor; involves a drug’s maximum effect
Efficacy
A plot of the proportion of the population that produces a response against the dose of the drug
Quantal-dose response curve
__________ effect is also known as either-or effect
Quantal
The dose at which 50% of individuals exhibit the specified quantal therapeutic effect
Median effective dose (ED50)
The dose at which 50% of individuals exhibit the specified quantal toxic effect
Median toxic dose (TD50)
The dose at which 50% of individuals exhibit the specified quantal lethal effect
Median lethal dose (LD50)
Refers to the range between the minimum therapeutic dose and the minimum toxic dose
Therapeutic window
Refers to the ratio of the dose that produces toxic effect in half the population (TD50) to the dose that produces therapeutic effect (ED50) in half the population
Therapeutic index
Refers to the ratio of the dose that produces toxic effect in 1% of the population (TD1) to the dose that produces therapeutic effect (ED99) in 99% of the population
Margin of safety
__________ is an example of a drug that has a small therapeutic index
Warfarin
__________ is an example of a drug that has a large therapeutic index
Penicillin