Acetylcholine

Question 1

Where do we get the choline for synthesis?

Answer 1

Recycled ACh

Breakdown of phosphatidylcholine

Question 2

What enzyme catalyses the formation of ACh?

Answer 2

Choline acetyltransferase

Question 3

What is the rate limiting factor of ACh synthesis?

Answer 3

Availability of substrate

Question 4

How does ACh inhibit its own release?

Answer 4

Binds to auto receptors on the presynaptic neuron

Question 5

How does botulinum toxin work?

Answer 5

Cleaves SNARE proteins so that neurotransmitters can’t be released

Question 6

Which transporter allows reuptake of choline into the presynaptic neuron?

Answer 6

Na+/choline symporter

Question 7

Where are M1 receptors predominantly found?

Answer 7

GI tract

Question 8

Where are M2 receptors predominantly found?

Answer 8

Cardiac muscle

Question 9

Where are M3 receptors found?

Answer 9

Smooth muscle
Endothelial walls of vessels
Exocrine glands

Question 10

What type of G protein is on M2 receptors in the heart?

Answer 10

Gi

Question 11

What type of G protein is on M3 receptors in the bronchi?

Answer 11

Gq

Question 12

What is the problem with atropine in general anaesthesia?

Answer 12

Too high doses can cross the blood brain barrier causing:

• high fever
• hallucinations
• coma

Question 13

What is ACh synthesised from?

Answer 13

Choline

Acetyl CoA