PED1003/L11 Drugs acting on PNS

Question 1

What does the autonomic nervous system control?

Answer 1

Smooth muscle and glands

Question 2

Describe the neurotransmitters in the sympathetic system.

Answer 2

Preganglionic ACh
Postganglionic NA

Question 3

Describe the neurotransmitters in the parasympathetic system.

Answer 3

Preganglionic & postganglionic ACh

Question 4

Describe the synthesis of acetylcholine. (2)

Answer 4

Synthesised by CAT from choline and AcCoA
Forms ACh and CoA

Question 5

What 2 main classes of ACh receptor are actions of ACh mediated by?

Answer 5

Muscarinic
Nicotinic

Question 6

What are the 3 subtypes of muscarinic receptor?

Answer 6

M1, 2, 3

Question 7

What are muscarinic receptors coupled to?

Answer 7

G-protein coupled receptor/ metabotropic receptor

Question 7

Where are muscarinic receptors located?

Answer 7

Postganglionic parasympathetic synapses

Question 8

What are the 2 main subtypes of nicotinic receptor?

Answer 8

Neuronal type
Muscle-type

Question 9

Where are nicotinic receptors located?

Answer 9

Brain and autonomic ganglia
Neuromuscular junctions

Question 10

What are nicotinic receptors coupled to?

Answer 10

Ligand-gated ion channels

Question 11

Name 2 muscarinic receptor agonists.

Answer 11

Pilocarpine
Carbachol

Question 12

How does pilocarpine help treat glaucoma?

Answer 12

Local application causes ciliary muscle contraction
Focus on near vision
Allows increase in drainage of aqueous humour

Question 13

Give a clinical use of muscarinic receptor agonists.

Answer 13

Treatment of xerostomia: dry mouth/reduced saliva secretions

Question 14

What can cause xerostomia? (3)

Answer 14

Radiation
Antineoplastic drugs
Side effects of many other drugs

Question 15

Give 3 side effects of pilocarpine. (muscarinic agonist)

Answer 15

Muscarinic-sweating
Nausea
Minimal cardiovascular side effects

Question 16

What is tropicamide used for? (muscarinic antagonist)

Answer 16

Pupil dilation in eye surgery
2-6 hour duration

Question 17

What is atropine used for? (muscarinic antagonist)

Answer 17

Resuscitation in bradycardia
Increase HR

Question 18

What is atropine and glycopyrronium used for? (muscarinic antagonists)

Answer 18

Decrease oral/respiratory secretions before oral procedures as as adjunct to anaesthesia

Question 19

What is ipratropium used for? (muscarinic antagonist)

Answer 19

Bronchodilation (asthma)

Question 20

What is hyoscine used for? (muscarinic antagonist)

Answer 20

Motion sickness
Orally decreases gastric motility

Question 21

Give an example of a nicotinic agonist.

Answer 21

Suxamethonium

Question 22

Give an example of a nicotinic antagonist.

Answer 22

Tubocurarine

Question 23

Describe the action of suxamethonium (nicotinic agonist). (3)

Answer 23

Initial depolarisation and muscle fibre contraction
Fibre consistently depolarised
Depolarising block

Question 24

Describe the action of tubocurarine (nicotinic antagonist) and give a potential use. (4)

Answer 24

Hyperpolarisation
Muscle fibre relaxation
Paralysis for surgery
Non-depolarising blocker

Question 25

Describe the action of hemicholinium (ACh synthesis). (3)

Answer 25

Blocks choline uptake
Inhibits synthesis
Blocks ACh transmission

Question 26

Give 2 drugs that inhibit ACh release.

Answer 26

Botulinum toxin
Bungarotoxin

Question 27

Give 2 drugs that affect cholinergic transmission.

Answer 27

Neostigmine
Organophosphates

Question 28

Give 2 effects of anticholinesterase on the autonomic nervous system.

Answer 28

Reflect increased transmission
Increase secretions
Bradycardia
Hypotension
Pupil constriction

Question 29

Give 2 effects of anticholinesterase on the NMJ.

Answer 29

Increased muscle tension and twitching
Large doses can causes depolarising block

Question 30

Give a use of neostigmine.

Answer 30

Treating myasthenia gravis - autoimmune disease in which circulating antibodies against muscle nicotinic receptors