5/6- Drug Receptor Interactions

Question 1

What is a receptor

Answer 1

Cellular macromolecule that interacts with a drug that changes one or more ongoing processes

Question 2

Do drugs initiate a new processs

Answer 2

No

Question 3

What are receptors coupled with

Answer 3

Effectors or ion channels (enzymes)

Question 4

Properties of receptors

Answer 4

Undergo synthesis and degradation

Number altered by diseases or chronic drug treatments

Question 5

Properties of drug receptor interactions

Answer 5

Reversible

Very fast

Question 6

What determines the concentration of the drug required to interact with receptor

Answer 6

Strength of interaction

Question 7

What do drug receptor interactions exhibit

Answer 7

Saturable response
Reversible
Good potency
Chemical sensitivity
Competitive blockade by antagonists
Amplified responses

Question 8

What are the 4 categories for drug receptors

Answer 8

Ion channels
GPCR (Guanine nucleotide binding protein-coupled receptor)
Receptor tyrosine kinases (TRK)
Intracellular receptor

Question 9

What types of drugs are GPCR

Answer 9

adrenegic 
Choline rain
Dopaminergic
Histamine 
Opiate
Serotonergenic

Question 10

Receptor ligands

Answer 10

Small molecules that interact with or bind to a cellular macromolecule

Question 11

Properties of receptor ligands

Answer 11

Associate very rapidly with receptors
After dissasociating response diminishes
Prolonged stimulation leads to diminished response
Full agonist produces a max effect
2+ agonists are no more effective than one

Question 12

What does a dose response curve for receptor agonists look like

Answer 12

Sigmoid
Semi-logarithmic
Need 2 orders or more of concentration to get a full range of responses

Question 13

What is a partial agonist

Answer 13

Drug that produces a sub maximal effect

Can decrease the response of a full agonist when both are used in combo

Question 14

Properties of receptor antagonists

Answer 14

Associate and disassociate slowly
Bind to receptor and block or prevent action of agonist
may be reversible or irreversible
Unable to elicit a response alone

Question 15

What is the efficacy of antagonist

Answer 15

0

Question 16

What are the 3 major antagonists used clinically

Answer 16

Competitive (most common)
Noncompetitive
Irreversible

Question 17

Properties of competitive antagonists

Answer 17

Bind reversibly to a receptor
Binding occurs at agonist binding
Mutually competitive with agonist

Question 18

Properties of non-competitive antagonists

Answer 18

Bind irreversibly or to alternate site of the receptor
Receptor blockade is fixed and related to the dose of antagonists
Cannot be overcome by raising the conc. Of the agonist

Question 19

what are simple models for drug receptor reactions based on

Answer 19

Single drug binding to single receptor to find a bimolecular complex
Reversible

Question 20

Dissociation constant (KD)

Answer 20

Predicts the relative conc. Of the drug receptor complex at any conc. Of the drug
Independent from any cell response
Can be determined for both agonists and antagonists

Question 21

Relevance of KD

Answer 21

Indicates drug conc. That is required in order for a drug to bind to a receptor
Not related to efficacy

Question 22

Potency

Answer 22

Dose of drug needed to produce a desired level of effect

Question 23

affinity

Answer 23

Drug conc. Require to occupy a target receptor

Question 24

Specificity

Answer 24

Measure of drug’s ability to produce a desirable effect relative to its ability to produce an undesirable effect

Question 25

Measures of drug safety

Answer 25

Compare drug doses with desired vs undesired effect

Question 26

Therapeutic index

Answer 26

TI = LD50/ED50

Lethality over effectiveness

Question 27

Margin of safety

Answer 27

MOS = LD1/ED99

Lethal effect in 1%/ effectiveness in 99%