Patient: Cholinergic drugs

Question 1

Difference between muscarinic and nicotinic acetylcholine receptors

Answer 1

Muscarinic: G-protein coupled, slow

Nicotinic: ligand-gated ion channel, fast transmission

Question 2

Name 3 sites of action for nicotinic acetylcholine receptors

Answer 2

CNS, NMJ, autonomic ganglia

Question 3

Name 3 sites of action for muscarinic acetylcholine receptors

Answer 3

CNS, Parasympathetic nervous system, sympathetic nervous system

Question 4

Describe nicotinic acetylcholine receptors using this:

1) -meric
2) number of subunits and receptor subtypes
3) built in/g protein
4) number of Ach sites
5) speed of response

Answer 4

1) Pentameric
2) 18 subunits of multiple types
3) built in ion channel
4) 2 Ach sites
5) microseconds to milliseconds

Question 5

Describe muscarinic acetylcholine receptors using this:

1) -meric
2) number of subunits and receptor subtypes
3) built in/g protein
4) number of Ach sites
5) speed of response

Answer 5

1) Monomeric
2) M1-5 subtypes, 5 receptor sites
3) Binding site for G protein
4) 1 Ach site
5) milliseconds to seconds

Question 6

Agonists of nicotinic acetylcholine receptors

Answer 6

nicotine, suxamethonium

Question 7

Antagonists of nicotinic acetylcholine receptors

Answer 7

atracurium, tubocurarine, alpha-bugarotoxin

Question 8

Agonists of muscarinic acetylcholine receptors

Answer 8

pilocarpine, muscarine

Question 9

Antagonists of muscarinic acetylcholine receptors

Answer 9

atropine, hyoscine

Question 10

Drugs acting at ACh

Answer 10

Paralyzing agents used in surgery*
Drugs to treat nicotine addiction*
Anti-emetic drugs*
Anti-asthma drugs*
Drugs used in eye exams
Drugs used to treat glaucoma
?Alzheimer’s disease drugs*
?Parkinson’s disease drugs
?Anti-schizophrenia drugs

Question 11

Drugs acting on ACh metabolism/release

Answer 11

ACh esterase (AChE)
Drugs to treat myasthenia gravis*
Drugs to treat Alzheimer’s disease*
Drugs to treat glaucoma
Nerve gases, insecticides*
ACh release
Botox*

Question 12

Name two type of blockers to neuromuscular transmission

mechanism-wise

Answer 12

Competitive antagonists at nAChR (flaccid paralysis)

Depolarising blockers agonists at nAChR

Question 13

How to reverse the effect of a competitive antagonist at the nAChR

Answer 13

Can be reversed by AChE inhibitors

Question 14

Can depolarising blockers (agonists at nAChR) be reversed with AChE inhibitors?

Answer 14

No

Question 15

Name a use of a neuromuscular transmission blocker

Answer 15

muscle relaxation in surgery

Question 16

Muscle relaxation doing surgery.. name some drugs which use the competitive antagonist of nAChR route

Answer 16

Atracurium
Pancuronium
Vecruonium
Gallamine
Tubocurarine

Question 17

Muscle relaxation doing surgery.. name some drugs which use the depolarising blocker agonists at nAChR route

Answer 17

Suxamethonium

Decamethonium

Question 18

What is Suxamethonium hydrolysed by? How long does it work for?

Answer 18

serum ChE

fast recovery - 3 minutes

Question 19

How does Atracurium break down?

Answer 19

Spontaneously breaks down

Question 20

Duration of action for Pancuronium? Uses?

Answer 20

100-200 minutes

Used for euthanasia and executions

Question 21

Tell me about a receptor involved in nicotine addiction/smoking cessation

Answer 21

Receptor containing α4 and β2 subunits may be important in nicotine addiction
Varenicline (Champix) = partial agonist at α4β2 receptor.
NICE concludes it is cheaper long term than NRT or bupropion

Question 22

Are agonists used with muscarinic drugs? Name two

Answer 22

Agonists not widely used
apart from
Pilocarpine in glaucoma 
and
bethanechol in bladder disorders

Question 23

Name 3 general effects of muscarinic antagonists

Answer 23

• tachycardia
• inhibits secretions (saliva, gastric acid)
• relaxes smooth muscle (GI tract, bronchi)

Question 24

Name some therapeutic effects of muscarinic antagonists

Answer 24

Anti-emetic
Anti-parkinsonian
(Amnesia, sedation)

Question 25

Name some muscarinic antagonists

Answer 25

Atropine Tiotropium, ipratropium Hyoscine Darifenacin, solifenacin

Question 26

Use of Atropine

Answer 26

Prevent bronchial secretions during surgery

Question 27

Use of Tiotropium and ipratropium

Answer 27

Inhaled bronchodilators in asthma | quaternary ammonium salts so not absorbed systemically

Question 28

Use of Hyoscine

Answer 28

treat motion sickness

Question 29

Use of Darifenacin and Solifenacin

Answer 29

Treat M3 selective bladder hyperactivity

Question 30

How does botulinum toxin work?

Answer 30

Blocks release of ACh by breaking down SNARE proteins

Question 31

Effects of botulinum

Answer 31

Paralysis of skeletal muscle, autonomic block | systemic effects can cause death

Question 32

Use of botulinum

Answer 32

Can be used to paralyse muscles on a local basis | muscle spasm treatment and cosmetic wrinkle removal

Question 33

List some irreversible acetylcholinesterase inhibitors

Answer 33

Sarin, VX

Question 34

What are sarin and VX used for?

Answer 34

irreversible acetylcholinesterase inhibitors nerve gases and insecticides causes muscle paralysis and over-activation of the autonomic nervous system (especially the parasympathetic route)

Question 35

How to counteract the effects of sarin and VX

Answer 35

Atropine can counter some symptoms via mAChR | Pralidoxime regenerates enzyme if administered within five hours.

Question 36

Name some competitive reversible AChEsterase inhibitors

Answer 36

Edrophonium Physostigmine Neostigmine Rivastigmine

Question 37

Name some non-competitive reversible AChEsterase inhibitors

Answer 37

Tacrine | Donepezil

Question 38

When are reversible AChEsterase inhibitors used?

Answer 38

In situations where there needs to be a boost cholinergic transmission

Question 39

Clinical uses of reversible AChEsterase inhibitors

Answer 39

Reversal of non-depolarizing NMJ blocker e.g. pancuronium Autoimmune myasthenia gravis immune attack on nAChR in NMJ. Increasing ACh boosts transmission via remaining receptors increases muscle strength edrophonium (test); pyridostigmine, neostigmine, physostigmine Alzheimer’s disease loss of cholinergic neurons tacrine, donepezil