Ch.5: Principals of Drug-Receptor Interactions Flashcards Preview

Pharmacology > Ch.5: Principals of Drug-Receptor Interactions > Flashcards

Flashcards in Ch.5: Principals of Drug-Receptor Interactions Deck (38):
1

drugs do/do not initiate new processes**

do NOT. They speed up or slow down already occurring processes.

2

endogenous substance*

substance naturally occurring in the body

3

Receptors are usually coupled to:*

an effector (transducer) or ion channel. Includes enzymes and receptor-gated ion channels

4

receptor "down regulation"*

excessive receptor stimulation --> decreased receptor density

5

receptor "up regulation"*

decreased receptor stimulation --> increased receptor density

6

effect of stopping long-term atenolol therapy?*

Will result in intense cardiac stimulation. Atenolol had been chronically blocking beta-1 receptors, leading to up-regulation of beta-1 receptors. If therapy is suddenly stopped, circulating EP will bind with these up-regulated beta-1 receptors, resulting in CV stimulation.

7

T/F there are variable life-times for different receptors*

T

8

There are an abundance of which receptors in vessel of skeletal muscle?*

beta-2 receptors

9

There are an abundance of which receptors in vessel of cutaneous skin?*

alpha-1

10

beta-2 receptor stimulation relaxes/constricts vascular smooth m.*

relax

11

What would be expected effect of EP on systemic blood pressure inthe presence of an agent that blocks alpha adrenergic receptors?***

drop in BP

12

T/F a drug with alpha-adrenergic blocking ability can stimulate the animal?*

T (i.e. acepromazine)

13

alpha-1 receptor stimulation relaxes/constricts vascular smooth muscle?

constrict

14

4 broad categories of receptors for drugs

1) ion channels
2) G-protein coupled receptors (GPCR)
3) receptor tyrosine kinase (TRK)
4) intracellular receptors

15

receptors that are coupled to G proteins and ion channels are common therapeutic agents*

:)

16

G protein coupled receptor types

adrenergic
cholinergic
dopaminergic
histamine
opiate
serotonergic

17

ion channel coupled receptors

nicotinic receptor gated Na+ channels
GABA receptor gated Cl- channels
Glutamate-coupled cation channels

18

T/F: a drug may have different actions on different classes of receptors*

T

19

What percent stimulation do full agonists have?*

100%

20

What percent stimulation do partial agonists have?*

1-99%

21

Competitive antagonists have reversible or irreversible binding?*

reversible

22

Non-competitive antagonists have reversible or irreversible binding?*

irreversible

23

Properties of Receptor Agonists (6)*

-bind rapidly
-response dissipates quickly after dissociating from receptor
-prolonged stim. of receptors leads to diminished response
-2 or more agonists are no more effective than 1 at max. conc.
-produce changes independent of other ligands
-full agonist produces a complete or maximal effect

24

Properties of Receptor Antagonists (5)*

-bind to receptor to prevent agonist binding
-have zero efficacy*
-usually bind and dissociate more slowly than agonists
-reversible or irreversible
-unable to elicit cellular or physiological actions when given alone

25

3 major types of antagonists used clinically. Which most common?*

-competitive, noncompetitive, irreversible. Competitive most common

26

competitive antagonist*

antagonist that binds REVERSIBLY to a receptor. Mutually competitive with agonist, and one can override the other when present in excess.

27

non-competitive antagonist*

antagonist that bind IRREVERSIBLY or bind to an alternate site on a receptor at which agonists do not compete.
-extent of blockage proportional to dose of antagonist
-cannot be overcome by raising conc. of agonist

28

How to remedy overdose of pancuronium, a paralytic agent that acts a competitive antagonist at nicotinic cholinergic receptors?*

use a short-acting AChE inhibitor, such as edrophonium

29

AChE works primarily on which receptors?*

nicotinic

30

AChE agents work how?*

(muscle relaxants). block nicotinic receptors and block AChE ability to bind

31

How to remedy overdose of non-competitive antagonist at nicotinic cholinergic receptor*

Can't. be careful!

32

dissociation constant (Kd)*

mathematical relationship that predicts the relative conc. of the drug-receptor complex at any conc. of drug
-the drug conc. at which half of the receptors are occupied by drug
-independent from cellular response

33

high affinity has low or high Kd?*

low

34

low affinity has low or high Kd?*

high

35

Why might a drug with high affinity not necessarily also have high potency?*

drug could have poor bioavailability, poor access to receptor site, etc.

36

Specificity (selectivity)*

measure of a drug's ability to produce one effect (desirable) relative to its ability to produce another effect (undesirable). The dose that creates an undesirable response in 50% of patients relative to dose that creates desirable response in 50% of patients

37

Drug has high (good) specificity if: *

ED50 (undesirable) >>> ED50 (desirable) (Want a large separation between desirable and undesirable effects)

38

drug safety is most commonly determined by:*

comparing drug doses that produce a desired effect (ED) relative to doses that are lethal (LD)
-a lot of species variation**