receptor theory 3: ⇒ antagonists II

Question 1

competitive antagonism

Answer 1

binds to receptor to form complex, but is unable to stimulate downstream signalling

Question 2

irreversible antagonism

Answer 2

• antagonism that cannot be reversed by washing the tissue
• once present it forms a bind at site and cannot be removed
• only solution is to form new receptor/ activate spare receptors

Question 3

non-competitive antagonism

Answer 3

Blocks some step in the process between receptor activation and response i.e. it does not compete with the agonist for the receptor site

Question 4

chemical antagonism

Answer 4

substances combine in solution so that the effects of the active drug is lost, i.e.the agonist is chemically altered by the antagonism

Question 5

pharmacokinetic antagonism

Answer 5

reduction in amount of drug absorbed, metabolised or excreted by another)

Question 6

physiological antagonism

Answer 6

The interaction of two drugs with opposing actions in the body

Question 7

Describe the effects of a reversible and irreversible competitive antagonist on the concentration-response curve for an agonist

Answer 7

• irreversible antagonists shift concentration-response curve to right and reduce max response
  = takes higher conc to produce a smaller response
• reversible competitive antagonists shift concentration-response curve to right but does not affect max response