Principles of Drug Action

Question 1

define drug

Answer 1

chemical substance of known structure, other than a nutrient or essential dietary ingredient. produces biological effect when administered to living organism.

Question 2

name a drug from genetic engineering

Answer 2

insulin

Question 3

what type of drug are beta blockers, AT1, and receptor blockers?

Answer 3

synthetic chemicals

Question 4

name the classes of drugs.

Answer 4

beta blockers, ACEI, AT1 (angiotensin II type 1) blockers, statins, NSAIDs, Anti histamines.

Question 5

what drug class is used for allergies?

Answer 5

anti histamines

Question 6

name the main kinds of regulatory proteins commonly involved as primary drug targets

Answer 6

receptors
enzymes
carrier molecules
ion channels

Question 7

what are the substances which act on beta 1 adrenoceptors in the heart?

Answer 7

noradrenaline: activates receptor.

beta blockers (e.g. atenolol): block beta 1 (and or beta 2) adrenoceptors

Question 8

what does activation of beta1 adrenoceptors of the heart entail?

Answer 8

increased heart rate and force of contraction. decreased duration of contraction and conduction time.

Question 9

define agonist. give example.

Answer 9

when bound, the receptor becomes activated

morphine

Question 10

define antagonist. give example.

Answer 10

blocker. binding does not lead to activation.

Beta blockers

Question 11

define affinity

Answer 11

ability of a drug to bind to a receptor. “affinity” of drug for receptor.

Question 12

what is the mass action equation describing?

Answer 12

simple bi molecular interaction between drug and receptor.

f = [D]/([D] + KD)

f = fraction of receptors occupied
[D] = concentration of drug (Molar)
KD = equilibrium dissociation constant of the drug for the receptor

Question 13

what do beta2 and beta1 adrenoceptors do in the heart?

Answer 13

mediate powerful increases in contractile force, hasten relaxation.

Question 14

define potency

Answer 14

a measure of a drug’s biological activity expressed in terms of the dose required to produce a pharmacological effect of given intensity.

-EC50 is the concentration of drug that causes 50% of the maximum effect of the drug

Question 15

ability for noradrenaline and adrenaline to cause cardistimulant effects is determined by:

Answer 15

concentration
affinity
efficacy

Question 16

define full agonist

Answer 16

agonist that produces maximal effect with respect to receptor, produce maximal effect by occupying less than 100% of receptors.

Question 17

name a full agonist (with respective receptor)

Answer 17

noradrenaline at b1-adrenoceptors in human right ventricle

Question 18

define partial agonist

Answer 18

produces submaximal effect with respect to that receptor, even when occupying 100% of receptors.

Question 19

name a partial agonist (with respective receptor)

Answer 19

cyanopindolol, b3 adrenoceptors in rat colon

Question 20

define efficacy

Answer 20

“strength” of agonist-receptor complex to evoke response.

(tendency of the drug-receptor complex to adopt active (AR*) rather than the resting (AR) state)

Question 21

constitutive receptors are:

Answer 21

receptors that are active without an agonist.

Question 22

what is the agonist that reduces the effects of constitutive agonists? (what are they called)

Answer 22

inverse agonists.

Question 23

what is meant by reversal of efficacy? what principle is it from?

Answer 23

when two drugs A and B act differently for different effectors. (switch between full agonist and no effect)

biased agonism (ligand directed signalling)

Question 24

what is the Schild plot?

Answer 24

The Schild equation describes the potency of a competitive antagonist in terms of its concentration and its ratio to the concentration of the agonist.

assess competitive nature of antagonists.

Question 25

Irreversible Antagonism. define and result of increasing concentrations of irreversible antagonists.

Answer 25

Can form a covalent bond with the receptor to reduce the number of ‘available’ receptors.

effect of agonist reduced. pEC50 ~ affinity of the agonist.

Question 26

what is Cheng and Prussoff equation, and what does it do?

Answer 26

Ki (CGP20712A) = IC50/(1 + [3HCGP 12177]/KD[3H]CGP 12177)

competition binding experiments. determines affinity. relates IC50 to Ki.

seems to be an experiment between (-)-[3H]CGP 12177 and CGP 20712A

Question 27

ACEI drug suffix?

Answer 27

-pril
Ex captopril

Question 28

Beta blocker suffix?

Answer 28

-olol
Ex. Propranolol