Pharmacodynamics Flashcards

1
Q

Definition of pharmacodynamics

A

effects of drugs on the body; drug receptors, dose-response curves, mechanisms of drug actions

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2
Q

Definition of receptor

A

specific molecule in a biological system that plays a regulatory role

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3
Q

Definition of ligand

A

molecule that binds to a receptor

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4
Q

Emax

A

maximal effect that can be produced by drug

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5
Q

ED50

A

dose of drug that produces 50% of its maximal effect

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6
Q

Graded dose-response curve is used for…

A

measuring the magnitude of a response with given doses, typically represents the mean value within a population or single subject

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7
Q

Quantal dose-response curve is used for…

A

determining if the “response” occurs, requires a pre-defined response

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8
Q

Non-cumulative quantal dose response curve

A

number or % of individuals responding at a dose of a drug and only at that dose

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9
Q

Cumulative quantal dose response curve

A

number or % of individuals responding at a dose of a drug AND at all doses lower than that dose

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10
Q

TD50

A

median toxic dose

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11
Q

LD50

A

median lethal dose

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12
Q

Therapeutic index

A

TD50/ED50

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13
Q

Therapeutic window definition

A

range of doses of a drug or of its concentration in a bodily system that provides for the safe and effective therapy

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14
Q

Potency

A

describes amount of drug required to produce a specific pharmacological effect; represented by ED50

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15
Q

Efficacy

A

maximal pharmacological effect a drug can produce, represented by Emax, related to total number of receptors available to bind a drug

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16
Q

Parameters that describe the interaction of a drug with a receptor

A

binding, affinity, selectivity, intrinsic activity

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17
Q

Covalent bond in drug-receptor binding

A

irreversible, requires drug removal and receptor activation requires re-synthesis of receptor or enzymatic removal of the drug

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18
Q

Non-covalent bonds in drug-receptor binding

A

reversible, most drugs bind to receptors via non-covalent bonds

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19
Q

Affinity

A

how readily and tightly the drug will bind to the receptor

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20
Q

Bmax

A

maximal binding

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21
Q

Kd

A

equilibrium dissociation constant, drug concentration at which 50% of the drug receptor binding sites are occupied by the drug

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22
Q

Kd/affinity relationship

A

lower Kd, higher affinity; higher Kd, lower affinity

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23
Q

selectivity

A

determined by its affinities at various binding sites

24
Q

Kd ratio

A

Kd, off target / Kd target

25
Q

Intrinsic activity

A

describes ability of a drug to change a receptor function and produce a physiological response upon its binding to a receptor

26
Q

Agonists

A

bind to receptor and stabilize it in a particular conformation, producing physiological response

27
Q

Antagonists

A

receptor antagonists bind to receptor but do not change its function, prevent activation of the receptor in the presence of an agonist

28
Q

Full agonist

A

fully activates receptors, produce a max pharmacological effect and has maximal intrinsic activity

29
Q

Partial agonists

A

partially activate the receptor, producing a sub-max effect

30
Q

Inverse agonist

A

produce an effect opposite to a full or partial agonist, decreases receptor signaling and response at receptors with a significant level of constitutive receptor activity

31
Q

Pharmacologic antagonism

A

action at the same receptor as endogenous ligands or agonist drugs

32
Q

Chemical antagonism

A

when chemical antagonist makes the other drug unavailable

33
Q

Physiologic antagonism

A

occurs between endogenous pathways regulated by different receptors

34
Q

Competitive antagonists

A

compete with endogenous chemicals or agonist drugs for binding receptor, can be displaced

35
Q

Non-competitive antagonists

A

irreversible or allosteric receptor inactivation

36
Q

Irreversible antagonists

A

irreversibly bind to and occlude agonist site on receptor by forming covalent bonds

37
Q

Allosteric antagonists

A

bind to a site other than the agonist site to prevent or reduce agonist binding or activation of receptor

38
Q

EC50 / Emax relationship in competitive antagonism

A

agonist EC50 increases, Emax does not change

39
Q

Emax / EC50 relationship in noncompetitive antagonism

A

agonist Emax decreases, EC50 does not change

40
Q

Signal transduction definition

A

process by which cells transmit, receive, and respond to info from their environment and from each other

41
Q

Steps of GPCR activation

A
  1. GPCR receives ligand
  2. Agonist activates receptor
  3. GDP release from Ga protein
  4. GTP enters into nt binding site
  5. G protein regulates activity of an effector enzyme or ion channel
  6. GTP hydrolysis and return to steady state
42
Q

Gs activation result

A

adenylyl cyclases activated

43
Q

Gi activation result

A

adenylyl cyclases inhibited

44
Q

Gq activation result

A

PLC activation

45
Q

G12/13 activation result

A

Rho GTPases resulting in cytoskeletal rearrangements

46
Q

cAMP second messenger pathway

A

Gs protein activates adenylyl cyclase and produces cAMP (hydrolyzed by PDE). Phosphorylated protein subunit produces a response

47
Q

DAG/IP3 signaling

A

G protein activates PLC which splits PIP2 into DAG and IP3. Ca-CaM complex forms and creates a response along with the phosphorylated protein substrate

48
Q

JAK-STAT path overview

A

Cytokine binds to JAK, resulting in phosphorylation of STAT molecules. STAT dimers travel to nucleus and regulate transcription

49
Q

JAK-STAT common cytokines

A

EPO, leptin, GH, leptin, Interferons, IL-2 to 10 and 15

50
Q

RTK pathway overview

A

cytokine binds and converts RTK to active dimeric state, auto-phosphorylate tyrosine residues which catalyzes the phosphorylation of other substrates, such as RAS GTPase

51
Q

RTK common cytokines

A

IGF-1, Insulin, VEGF, EGF, NGF, PDGF

52
Q

Mutations in Ras proteins are most common in which types of cancer

A

pancreatic adenocarcinomas

53
Q

Mutations in Raf proteins are most common in which types of cancer

A

melanomas

54
Q

Nuclear receptors

A

ligand-activated transcription factors that modulate gene activity, ligands are lipophilic molecules that are able to cross the cell membrane

55
Q

Common ligands for nuclear receptors

A

lipophilic molecules, steroid hormones, thyroid hormones, Vitamins D and A, lipid mediators