Drug Receptor Interactions

Question 1

Receptors are usually coupled to a ?

Answer 1

effector (transducer)

or ion channel

Question 2

difference between the effects of epinephrine on cutaneous v. skeletal muscle vessels?

Answer 2

cutaneous - more alpha1 -> constricts vascular smooth m.

skeletal - more beta 2 -> relaxes vascular smooth m.

Question 3

Drug response depends on the ___________ at that tissue

Answer 3

type (and #) of receptor

Question 4

receptors undergo ____ & _____ like other cellular proteins

Answer 4

synthesis & degredation

Question 5

excessive receptor stimulation results in ____________ and vice versa

Answer 5

“Down Regulation”

Decreased Receptor Density

Question 6

6 qualities that drug-receptor interactions typically exhibit?

Answer 6

saturable
reversible
potent
chemically selective
allow competition
amplified responses

Question 7

4 broad categories for receptors

Answer 7

ion channels
G-Protein Coupled receptors
receptor tyrosine kinases
intracellular receptors

Question 8

All of these are? (adrenergic, cholinergic, dopaminergic, histamine, opiate, serotonergic)

Answer 8

GPCR

Question 9

All of these are? (Nicotinic, GABA, Glutamate)

Answer 9

ion channel coupled receptors

Question 10

Which types of antagonists are reversible?

Answer 10

competitive - reversible

non-comp - irreversible

Question 11

tend to bind rapidly, and have a response that dissipates quickly after dissociation

Answer 11

receptor agonists

Question 12

why can prolonged stimulation of receptor lead to diminished response

Answer 12

tolerance
tachyphylaxis (run down of channel following overstimulation)

Question 13

2 + agonists are not more effective than one

Answer 13

True at maximal concentrations

Question 14

Risk of using a partial and full agonist when used in combination?

Answer 14

partial can decrease the response to a full agonist (no matter how much you increase the concentration of the full agonist)

Question 15

antagonists have _____ efficacy

Answer 15

zero

Question 16

typically dissociate from the receptor slowly

Answer 16

antagonists

Question 17

most common antagonist used clinically

Answer 17

competitive

Question 18

Can the effect of competitive antagonists be overcome by increasing agonist dose?

Answer 18

yes

Question 19

extent of receptor blockade is fixed and related to dose when a _______ is administered

Answer 19

non-competitive antagonist

Question 20

Can the effect of a non-competitive antagonist be overcome by increasing agonist dose?

Answer 20

nope

Question 21

What is the practical relevance of Kd (dissociation constant)?

Answer 21

affinity

indicates relative drug concentration required to bind a receptor (no relationship with efficacy!)

Question 22

how does affinity affect Kd?

Answer 22

high affinity -> low dissociation constant

Question 23

affinity v. potency?

Answer 23

potency= dose needed to produce desired effect
affinity= concentration required to occupy target receptor

Question 24

specificity?

Answer 24

measure of drugs ability to produce desirable effect relative to undesirable effect
(ED50/ED50)

Question 25

What is ED50?

Answer 25

dose that produces effect in 50% of target animal species

Question 26

drug safety is most commonly determined by comparing drug doses that produce a ___ relative to ____

Answer 26

desired effect

lethal dose

Question 27

Therapeutic index

Answer 27

Lethal dose (LD50) / effective dose (ED50)

Question 28

Safer drugs have a ________ therapeutic index

Answer 28

larger

Question 29

a more stringent measure of drug safety than therapeutic index is?

Answer 29

margin of safety (MOS)

Question 30

MOS =?

Answer 30

LD1/ED99