antagonist

Question 1

true or false:
- agonist is a ligand which binds to a receptor and causes. biological response
- antagonist binds to a receptor but has no effect and prevents other ligands from binding

Answer 1

true

Question 2

—- is the ability to produce a response
full agonist when a =
partial agonist when a
antagonist when a

Answer 2

intrinsic activity aka efficacy
- a=1
- 1>a<0
- a =0

Question 3

1.—- binds to the same site as the agonist and two compete w each other
2. the binding is —- and biding is surmountable by —-
3. the max effect of agonist is —-
4. dose of agonist is required to reach max effect is —-

Answer 3

• competitive antagonist
• reversible
• excess agonist
• unchanged
• increased
  ( check graph slide 9 )

Question 4

1.non competitive antagonist binds to a —- site of the agonist
2. binding is —-
3. often called :
4. binding cant overcome by — agonist concentration
5. Bmax/ Emax is —

Answer 4

• different
• reversible
• allosteric antagonist or inhibitor
• increasing
• reduced
  ( check slide 8)

Question 5

• agonists are compared by the dose that causes — response
• antagonists are compared by their — on the dose response curve
• the dose that inhibits the response of agonist by 50% is —-
• to do this experimentally the dose of agonist is selected that gives a — response
• then the increasing doses of antagonist are added and then agonist response is recorded

Answer 5

• 50% response EC50
• effect
• IC50
• defined

Question 6

in competitive inhibition:
the EC50 is —- with the competitive antagonist concentration
log dose curve shifts —
the Emax is —-

Answer 6

• increased
• right
• unaffected

Question 7

the noncompetitive inhibition is
EC50 is —-
the Emax is —-

Answer 7

• unchanged
• reduces w non-competitive antagonist concentration
  ( goes down )

Question 8

reversible antagonist:
can be — by other ligands and binds —-
irreversible antagonist:
some drugs can bind to the receptor —-
usually involves —- binding to receptor
as:

Answer 8

• displaced
• non covalently
• irreversibly
• covelant
• clopidogeral binds irreversibly to P2Y12

Question 9

—– binds to a receptor like an agonist but induces an opposite signiling outcome to an agonist

Answer 9

inverse agonist

Question 10

loss of drug response:
—– the effect of the drug diminished when its given repeatedly or continuously
—– is similar but develops slow
- refractories can due to:

Answer 10

-desensitisation/tachyphylix
- tolerance
1. change or loss of receptors ( beta receptor agonist )
2. exhaustion of mediator ( amphetamine )
3. increased metabolic degradation ( alcohol )
4.physiological adaptation ( diuretic –> RAS )

Question 11

what if the drug response is not linear or easily measured?
—– can be constructed for responses that are measured on continuous scale as heart rate
- sometimes effects are nothing or all as quantal rather graded
- sleep death infection pregnancy presence or absence of epileptic seizures , presence or absence of infection

Answer 11

• graded dose response curve

Question 12

how can we measure potency, safety of drugs?
——- can be constructed for the drugs that elicit an all or none response
the response ( y axis) is the % of—- who respond to a particular drug

Answer 12

• frequency distribution or quantal dose response curve
• people

Question 13

the effective dose ( ED50 ) :
- helps identify —— required to elicit therapeutic benefit
- its the dose required to produce a therapeutic effect in —- of the tested population

Answer 13

• drug dose
• 50%
  ( check graph slide 16)