intro to pharmacology

Question 1

drugs and receptors

Answer 1

-Drugs interact with receptors, which can be found on the cell surface or intracellularly.
-The role of a receptor is to recognise a stimulant and translate this into activation of the cell. To do this, receptors must be specialised and localised.

Question 2

agonists

Answer 2

• substances which produce a response

Question 3

antagonists

Answer 3

substances which block a response are called antagonists

Question 4

agonist and antagonist act on same receptor

Answer 4

1)There must be chemical similarities between them to explain why they interact with the same receptor.

2)There must also be chemical differences to explain why one activates and the other does not activate the receptor.

Question 5

ligand

Answer 5

a chemical/compound that binds to a receptor

Question 6

partial agonist

Answer 6

a low efficacy agonist that is unable to elicit the maximal response from a receptor, irrespective of the concentration applied

Question 7

affinity

Answer 7

• a measure of equilibrium constant of the reversible reaction between a drug and a receptor

Question 8

efficacy

Answer 8

a measure of the magnitude of the cellular response produced when an agonist binds to a receptor

Question 9

potency

Answer 9

a measure of the concentration of a drug at which it produces an effect of a magnitude

Question 10

receptor occupancy

Answer 10

• increases with increasing agonist concentration. However, this relationship is not linear but hyperbolic. As the receptor needs to be occupied to be activated in order to elicit a response, the dose-response curve for an agonist is also hyperbolic.

Question 11

agonist vs antagonist

Answer 11

agonist- activates receptor and posses both affinity and efficacy
antagonist- does not activate receptor and posses only affinity

Question 12

two ways an antagonist can operate

Answer 12

By binding to the same site as the agonist and competing with it

Binding to a different site to the agonist which causes a change in the receptor to prevent or restrict agonist binding

Question 13

competitive antagonist

Answer 13

• binds to same site as agonist and competes for binding
• the effect of a competitive antagonist can be overcome by increasing agonist concentration

Question 14

non-competitive antagonists

Answer 14

• will bind to a site that is different from the agonist binding site
• will causes a conformational change in the receptor which restricts agonist binding
• cannot be overcome by increasing agonist concentration