drugs and receptors

Question 1

define the term drug

Answer 1

a medicine or other substance which has a physiological effect when ingested or otherwise introduced into the body

Question 2

what are the 4 drug targets?

Answer 2

Receptors
Enzymes
Transporters
Ion channels

Question 3

define pharmacology

Answer 3

the branch of medicine concerned with the uses, effects and modes of action of drugs

Question 4

define receptors

Answer 4

a component of a cell that interacts with a specific ligand and initiates a change of biochemical events leading to the ligands observed effects.

Question 5

what are exogenous receptors?

Answer 5

drugs ( extrinsic)

Question 6

what are endogenous receptors?

Answer 6

hormones, neurotransmitters (intrinsic)

Question 7

what chemicals communicate via receptors?

Answer 7

neurotransmitters -(acetylcholine, serotonin), autacoids -(cytokines, histamine) and hormones-(testosterone, hydrocortisone).

Question 8

what are the type of receptors?

Answer 8

ligand gated ion channeles
G protein coupled receptors
kinase linked receptors
cytosolic/ nuclear receptors

Question 9

name an example of a ligand gated ion Channel?

Answer 9

nicotinic ACh receptor

Question 10

what are ion channels?

Answer 10

are pore-formingmembrane proteinsthat allowionsto pass through the channel pore so that the cell undergoes a shift inelectric chargedistribution

Question 11

describe G protein coupled receptors

Answer 11

• have 7 membrane spanning region ( largest/most diverse group of membrane receptors)

Question 12

give examples of ligands

Answer 12

light energy, peptides, lipids, sugar and proteins

Question 13

what are G proteins?

Answer 13

also known asguanine nucleotide-binding proteins, are a family of proteins (35 in humans) involved in transmitting signals from GPCRs

Question 14

what is the activity of G proteins regulated by?

Answer 14

by factors that control their ability to bind to and hydrolyzeguanosine triphosphate(GTP) toguanosine diphosphate(GDP

Question 15

what are kinases?

Answer 15

enzymes that catalyse the transfer of phosphate groups between proteins- phosphorylation

Question 16

what are kinase linked receptors?

Answer 16

receptors for growth factors

Question 17

how do kinase linked receptors work?

Answer 17

activated when binding of an extracellular ligand causes enzymatic activity on the intracellular side

Question 18

how do nuclear receptors work?

Answer 18

work by modifying gene transcription in. aligns or oestrogen dependant manner

Question 19

what are nuclear receptors?

Answer 19

steroid receptors

Question 20

how does tamoxifen work?

Answer 20

• acts as aselective estrogen receptor modulator(SERM), or as apartial agonistof theestrogen receptors
• Used in Oestrogen positive cancers.

Question 21

what happens if you have increased histamine?

Answer 21

allergy

Question 22

what happens if you have reduced dopamine?

Answer 22

parkinsons

Question 23

what happens if you loose acetylcholine receptors?

Answer 23

myasthenia gravis

Question 24

what happens if you have increased c kit receptor?

Answer 24

mastocytosis

Question 25

features needed to develop a therapeutic strategy?

Answer 25

Identify the receptor involved in a pathophysiological response Develop drugs that act at that receptor Quantify drug action at that receptor

Question 26

describe agonist

Answer 26

a compound that binds to a receptor and activates it

Question 27

describe antagonists

Answer 27

a compound that reduces the effect of an agonist

Question 28

describe ligands

Answer 28

a molecule that binds to another (usually larger) molecule

Question 29

what are the two categories of cholinergic receptors?

Answer 29

nicotinic muscarinic

Question 30

antagonist of muscarine

Answer 30

atropine

Question 31

receptor of muscarine

Answer 31

mAChR

Question 32

antagonist of nicotine

Answer 32

curare

Question 33

receptor of nicotine

Answer 33

nAChR

Question 34

define affinity

Answer 34

describes how well a ligand binds to the receptor

Question 35

describe efficacy?

Answer 35

describes how well a ligand activates the receptor

Question 36

describe agonists in terms of affinity and efficacy

Answer 36

have both

Question 37

what is intrinsic activity?

Answer 37

refers to the ability of a drug-receptor complex to produce a maximum functional response

Question 38

what is competitive antagonism

Answer 38

when the antagonist and agonist bind to the same site and compete

Question 39

what is non competitive antagonism?

Answer 39

antagonist reverses the effect of the agonist the antagonist bins to an allosteric site on the receptor- different to the agonist

Question 40

what is selective agonism?

Answer 40

potency of a range of agonists

Question 41

what is selective antagonist

Answer 41

competitive antagonist

Question 42

what are the two categories receptors are classified in?

Answer 42

Selective agonism Selective antagonist

Question 43

what are the factors governing drug action?

Answer 43

receptor related tissue related

Question 44

what does receptor related include?

Answer 44

affinity efficacy

Question 45

what does tissue related include?

Answer 45

receptor number signal amplification

Question 46

what happens if b2-adrenoceptors are inactivated?

Answer 46

Isoprenaline is a non-selective β adrenoreceptor agonist an analog of adrenaline). relaxation of pre-contracted human bronchial rings

Question 47

what are irreversible antagonists

Answer 47

the receptor itself will never become available for signalling again will be stuck to it

Question 48

what is the importance of reserve receptors?

Answer 48

Some agonists needs to activate only a small fraction of the existing receptors  to produce the maximal system response. -reserve can be large or small; depends on tissue

Question 49

do partial agonists have reserves

Answer 49

No receptor reserve for a partial agonist even with 100% occupancy, maximal response not seen

Question 50

what is sign transduction?

Answer 50

a basic process involving the conversion of a signal from outside the cell to a functional change within the cell.

Question 51

what does signal amplification do?

Answer 51

increase the strength of a signal ( Can be a large response or a short response)

Question 52

what is allosteric modulation?

Answer 52

When an allosteric ligand binds to a different site on the molecule and prevents the signal from being transmitted. - ultimately effecting the same pathway

Question 53

what is inverse agonism?

Answer 53

When a drug that binds to the same receptor as an agonist but induces a pharmacological response opposite to that of the agonist.

Question 54

describe tolerance

Answer 54

- the reduction in drug effect over time - Used continuously, repeatedly in high concentrations -slow

Question 55

describe desenstitization

Answer 55

-suddenly whole system becomes uncoupled -failed to get any sort of response -could be due to degradation -internalised -rapid

Question 56

how to describe activity of compounds?

Answer 56

better to say selective when describing activity than specific as no compounds is every truly specific

Question 57

what is salbutamol an agonist for?

Answer 57

a b2-adrenoceptor agonist

Question 58

What is salbutamol selective for?

Answer 58

is selective for b2-adrenoceptors