Agonists and Antagonists

Question 1

What effect(s) would you expect a muscarinic antagonist such as atropine to have?

Answer 1

Dilate the bronchi and reduce salivation

Question 2

Salmeterol acta at a lower dose than salbutamol, therefore it is said to be more … what?

Answer 2

Potent

Question 3

Prolonged treatment with an agonist can lead to … what?

Answer 3

Desensitisation

Question 4

What type of molecules are receptors?

Answer 4

Proteins

Question 5

Name the two types of receptors for the neurotransmitter acetylcholine

Answer 5

Muscarinic and nicotinic

Question 6

What term would you use to describe a drug that activates a receptor protein to cause intracellular signalling?

Answer 6

Agonist

Question 7

Name the four broad structural types of receptors.

Answer 7

Ligand-gated ion channel, G protein coupled, tyrosine kinase and cytoplasmic/nuclear.

Question 8

Which type of receptor is best suited to very fast responses?

Answer 8

Ligand-gated ion channel receptor

Question 9

Drugs working at which type of receptor are likely to take a day or more to generate a response?

Answer 9

cytoplasmic/nuclear

Question 10

True or False: in a drug-receptor complex, the receptor alters the substrate site of the drug

Answer 10

False

Question 11

Naloxone can be described as what in regards to morphine?

Answer 11

Competitive antagonist

Question 12

An increase in the concentration of mepyramine during an allergic response would decrease the action of what agonist at which receptors?

Answer 12

Histamine at the H1 receptors

Question 13

What response would be displayed if Naloxone was given in the absence of opiate use?

Answer 13

Nothing

Question 14

Name the two receptor subtypes

Answer 14

Voluntary and smooth muscle

Question 15

What action does atracurium have on nicotinic receptors, and what effect does this have on the body?

Answer 15

Competitive antagonist, paralysis

Question 16

Atropine is a selective antagonist for what receptor subtype?

Answer 16

Muscarinic

Question 17

What effect does acetylcholine (a neurotransmitter) have on muscarinic receptors in smooth muscle?

Answer 17

Salivation and constriction of bronchi

Question 18

What effect does acetylcholine (a neurotransmitter) have on nicotinic receptors in voluntary muscle?

Answer 18

Contraction and movement

Question 19

True or False: salbutamol and adrenaline are chemically similar

Answer 19

True

Question 20

Salbutamol’s desired effect is on what receptors in smooth muscle?

Answer 20

Beta-2 adrenergic receptors

Question 21

What unintended effect can Salbutamol have due to binding to another receptor site?

Answer 21

Tachycardia and arrhythmias due to binding in the atrial beta-2 adrenergic receptors

Question 22

What is cyclic adenosine monophosphate (cAMP)?

Answer 22

Intracellular messenger

Question 23

How would you describe an antagonist that binds at a different site to an agonist?

Answer 23

Non-competitive antagonist

Question 24

What are the three subunits of G proteins?

Answer 24

Alpha, beta and gamma

Question 25

Drug agonists are made to imitate the action of ligands, name some ligands of G-protein coupled receptors.

Answer 25

Ions, amino acids, neurotransmitters, peptides, proteins and hormones.

Question 26

Ligand gated ion channels are important in what types of cells, and why?

Answer 26

Nerve and muscle cells, because they rely on changes in electrical energy caused by the movement of ions

Question 27

Examples of ligand gated channel receptors include

Answer 27

Acetylcholine, GABA, glycine, 5HT3

Question 28

Insulin interacts with what type of receptor?

Answer 28

Enzyme linked receptor

Question 29

Cytoplasmic/nuclear receptor ligands must be able to cross the cell membrane because the receptors lie inside the cell, these ligands are mainly from what family of proteins?

Answer 29

Hormones

Question 30

40% of medicines interact with what type of receptor?

Answer 30

G-protein coupled

Question 31

Gap junctions between cells provide quick communication and transfer of small molecules between adjacent cells, this is important where?

Answer 31

In electrical activity such as between cardiac myocytes

Question 32

Both antagonists and agonists have affinity for a receptor but only agonists have efficacy. What is affinity and efficacy?

Answer 32

Affinity- how tightly the drug binds to the receptor Efficacy- activates and stimulates a response

Question 33

What is potency?

Answer 33

The concentration required to give half the maximum response

Question 34

What is an allosteric antagonist?

Answer 34

Binds to the allosteric site (different to main receptor site)

Question 35

What is IC50 in relation to antagonists?

Answer 35

Inhibitory concentration for 50% inhibition/potency