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Flashcards in DRug receptors Deck (58):
1

what is pharmacodynamic

what the drug does to the body

2

what is pharmacokinetics

what the body does to the drug

3

what is a ligand

substance that forms complex with receptors ex.drugs

4

what is a receptor

proteins that can bind to ligands

5

where can receptors be located

cell membrane
cytoplasm
nucleus

6

what does the receptor binding to the ligand do to post receptor signalling

activates or inactivates

7

what are the four receptor families

g protein coupled receptors
ion channels
enzyme linked receptors
intracellular receptors

8

what is the most common site of drug action

g protein coupled receptors

9

describe the structure of a receptor

single alpha helical peptide with seven transmembrane domains
extracellular domain contains the ligand binding area

10

describe the structure of a g protein

alpha subunit with diff forms
beta gamma subunit

11

what does the alpha subunit do

can bind to GDT and GTP

12

what does the BY subunit do

inhibits alpha subunit

13

how does the g protein function

occupied receptor changes shape and interacts with g protein which releases GDP and binds GTP. alpha subunit dissociates and activates adenylyl cyclase. hormone no longer present receptorconverts to resting state and GTP hydrolyzed to GDP

14

alpha subunits act on what? which on is inhibitory

adenylate cyclase
i is inhibitory

15

subunit q activates what

Phospholipase C

16

what are the second messengers activated by g proteins

camp
IP3
DAG
Ca

17

how do ligand channels work

ligand binding triggers confomational change in receptor and the channel opens

18

what is the ligand gated sodium channel

nicotinic acetylcholine

19

what is theligand gated calcium channel

NMDA

20

what is the ligand gated chloride channel

GABA

21

how are voltage gated channels different from ion gated

activated by changes in membrane ds potential not ligan

22

what is an ion pump

transmembrane protein that moves ions across pm against their concentration gradient

23

what is the cell membrane enzyme linked receptor

tyrosin kinase receptor

24

what is the structure of a tyrosin kinase receptor

spans the membrane in the form of dimers or multisubunit complexes

25

how does the tyrosin kinase receptor function

ligand binds to receptor causing a conformational change forming dimers and converts kinases to active forms
induces receptor autophosphorylation

26

what is an example of a intracellular enzyme lonked receptor

soluble guanylyl cyclase

27

what is the structure of guanylyl cyclase

forms hterodimer with alpha and beta subunit
regulatory domain
coiled coil domain
cyclase domain

28

how does guanylyl cyclase function

activated by nitroc oxide
activates second messenger cGMP

29

what is the structure of a intracellular nuclear receptor

ligand binding part and DNA binding part
in nucleus

30

how do nuclear receptors function

ligand diffuses into cell and interacts with the nuclear receptor then translocates to the nucleus
activated receptor binds to promoter region of gene resulting in gene expression

31

what is bmax

maximal specific bindign of a ligand to receptor

32

what is kd

concentration of drug where half maximal binding is observed

33

describe affinity

how attracted the drug is to the receptor

34

how does kd relate to affinity

as kd decreases the affinity increases

35

describe selectivity

preference for one receptor over another

36

what is e max

max effect induced by the drug

37

ec50

concentration of the drug that produces an effect that is half the max

38

describe potency

amount of drug needed to produce a given magnitude

39

describe efficacy

ability of a drug to elicit a biological response by agonist, determined by emax

40

what is an agonist

agent that can bind to a receptor and elicit a biologic response

41

what is a full agonist

produces max response, mimics

42

what is a partial agonist

activates receptor with a lower efficacy, will reduce effects of full agonist

43

what is an inverse agonist

has a negative effect on the receptor

44

what is an antagonist

drug combines wiht receptor but produces no response

45

how do competitive antagonists work

compete with agonist by binding to the same site on the receptor, can be overcome by increasing concentration of agonist

46

how do non competitve antagonists work

bond covalently or with such high affinity those receptors are unavailable to agonists

47

how do allosteric antagonists work

bind to allosteric site which prevents receptor from activating even when agonist is attached

48

define adverse effect

undesired harmful effect resukting from a medication

49

what is TD50

drug dose that produces toxic effect in 50% of patients

50

what is ED50

drug dose that produces therapeutic effect in 50% of patients

51

how is ED50 and EC50 different

EC is to reach 50% of max biological response which ED is for 50% to reach therapeutic response

52

how do you calculate the therapeutic index

TD50/ED50

53

what does it mean if TI is high

there is a wide therapeutic window so it has high safetyy

54

define idiosyncratic

individuals exhibit an unusual drug response

55

define tachyphylaxis

acute rapid loss of response to a drug

56

define tolerance

decreased response to a drug when the drug is taken repeatedly

57

what is receptor desensitization

mechanism that reduces the receptor response to an agonist

58

what are the four phases in drug development

1: small number, screen for safety
2: study efficacy
3: larger, safety and efficacy
4: large number post marketing studies