Receptors

Question 1

What are some examples of drug targets

Answer 1

Enzymes
Nuclei acids (DNA and RNA)
Carrier molecules or transporters- pump ions across cell membranes
Ion channels- pores across vell membranes that allows ions to enter
Receptors

Question 2

What are receptors

Answer 2

Highly specialised proteins embedded in cell membranes that possess structurally defined bind in sites which specifically interact with particular complementary sites on the drug molecule

Question 3

Difference between enzyme and receptor

Answer 3

Enzyme facilitates the reaction
Receptor enables the cell to generate a response

Question 4

Evidence for receptors

Answer 4

Potency= drugs are highly potent as small quantities are required to produce an effect
Unique actions= drugs can have different actions on different tissues
Specificity
Antagonism= the actions of drugs can be prevented by other drugs

Question 5

Receptor types

Answer 5

Ionotropic = linked to ion channel, takes ms
Metabotropic= activates G protein and second messenger proteins, takes ms-seconds
Enzyme linked= two receptors, further signalling molecules, takes minutes
Steroid= diffuses against cell membrane, transport to the nucleus for activation of transcription and translation, minutes to Hours

Question 6

Drug receptor interaction

Answer 6

drug + response = drug response complex= response

Reversible reactions because of weak hydrogen bonds

Question 7

What does the magnitude of the response depend on

Answer 7

Existence of receptors
Number of receptors occupied by drugs
Intracellular signalling cascade

Question 8

Potency of a drug

Answer 8

Measure of the ability of a drug to bind to receptor

Question 9

Measure of potency

Answer 9

Ka= association constant
Kd= dissociation constant = 1/Ka

Question 10

Efficacy

Answer 10

Measure of the ability of drug- receptor complex to produce a response
Ka/Kb

Question 11

Agonists

Answer 11

Binds to receptors and produce a response

Question 12

Antagonists

Answer 12

Binds to receptors but do not activate receptors

Question 13

Types of agonists

Answer 13

Full agonists= able to evoke a maximal response
Partial agonists= incapable of evoking a maximal response
Inverse agonists

Question 14

Two state models of receptor function

Answer 14

Agonist = much higher affinity for receptor in active state than R
Partial agonist= sill bind to both resting state and active state