Essential pharmacology

Question 1

What is a receptor

Answer 1

Detect signalling molecules and initiate response
Response proportional to amount of singalling molecules until fully saturated

Question 2

What are the basic types of receptors

Answer 2

Cell surface receptors
Intracellular receptors
Ion channels
Carriers
Enzymes
Nucleic acids

Question 3

What is affinity

Answer 3

Strength of chemical attraction between drug and receptor - low EC50 indicates high affinity

Question 4

What is efficacy

Answer 4

How good drug is at activating receptor

Question 5

What is an agonist and antagonist

Answer 5

Agonists mimic normal effect of receptor
Antagonists block normal action of receptor

Question 6

What is affinity of a drug for a receptor

Answer 6

Extent to which a drug binds to receptors at any given drug concentration

Question 7

What is the efficacy of an agonist

Answer 7

A measure of how well an agonist can stimulate a response to receptor

Question 8

What is receptor secificity

Answer 8

Chemical signals produced by one cell can only be detected by another cell with specific receptor
Different receptors for same chemical signals can produce different responses in different cells
Allows specificity – right response from the right cells

Question 9

What are the different receptor responses

Answer 9

Rate of proliferation or differentiation
Secretory activity
Contractile activity
Metabolism
Membrane permeability

Question 10

Describe intracellular receptors

Answer 10

Some signalling molecules are lipid soluble
Dissolve through membrane bilayer
Bind to intracellular receptors
(steroid hormone)

Question 11

What are the different types of cell surface receptors

Answer 11

Receptor channels
G protein coupled receptors (GPCP)
Receptor enzymes
Integrin receptors

Question 12

Describe receptor channels

Answer 12

Ligand binding open or closes channels

Question 13

Describe G protein coupled receptors (GPCR)

Answer 13

Ligand binding opens ion channel or alters enzymes activity
Biggest class of cell surface receptors
Different G proteins couple to different 2nd messenger systems

Question 14

Describe Receptor enzymes

Answer 14

Ligand binding activates intracellular enzyme

Question 15

Describe integrin receptors

Answer 15

Alters enzymes or cytoskeleton

Question 16

Describe GPCR coupled to ion channels

Answer 16

Affects membrane potential and firing of action potentials

Question 17

Describe GPCR coupled to adenylyl cyclase

Answer 17

Produces cAMP as 2nd messenger
Regulates protein kinase A activity
Phosphorylates target proteins and changes their activity

Question 18

Describe GPCR coupled to phospholipase C

Answer 18

Produces IP3 and DAG as 2nd messengers
Releases Ca2+ and regulates protein kinase C activity
Phosphorylates target proteins and changes their activity

Question 19

How is Ca+ released

Answer 19

Internal stores - IP3- or Ca2+
Stimulated release Ca2+ from ER

Outside cell - voltage/ligand-gated Ca2+ channels
Inhibits Ca2+ transport out of cell

Question 20

What are the effects of Ca+ as second messenger

Answer 20

Directly affects target protein
Binds to calmodulin which activates target protein
Works via other Ca2+ binding protein

Question 21

What is a selective agonist

Answer 21

Drugs that activate only some of those receptors

Question 22

What is a selctive antagonist

Answer 22

Drugs that block only some of those receptors