Session 10

Question 1

What neurotransmitter do pre-ganglionic neurones use in the Sympathetic branch of the ANS?

Answer 1

Acetylcholine

Question 2

What neurotransmitter do pre-ganglionic neurones use in the Parasynpathetic branch of the ANS?

Answer 2

Acetylcholine

Question 3

What neurotransmitter do post-ganglionic neurones use in the Sympathetic branch of the ANS?

Answer 3

Noradrenaline

Question 4

What neurotransmitter do post-ganglionic neurones use in the Parasympathetic branch of the ANS?

Answer 4

Acetylcholine

Question 5

What receptors receive acetylcholine in the ANS?

Answer 5

Nicotinic

Question 6

What is Acetylcholine synthesised from?

Answer 6

Choline using the choline acetyltransferase enzyme

Question 7

What are NANC transmitters?

Answer 7

Non Adrenergic, Non Cholinergic transmitters.

Question 8

When are NANC transmitters released?

Answer 8

They can be co released with Noradrenaline/Acetylcholine

Question 9

What are some examples of NANC transmitters?

Answer 9

NO
ATP
5HT

Question 10

What are the 2 termination mechanisms of noradrenaline?

Answer 10

Uptake 1

Uptake 2

Question 11

What is Uptake 1?

Answer 11

Noradrenaline is terminated by reuptake into the presynaptic terminal by a Na+ dependent transporter

Question 12

What is Uptake 2?

Answer 12

Noradrenaline is not recaptured by Uptake 1 and is taken up by a lower affinity non neuronal mechanism

Question 13

What degrades Acetylcholine?

Answer 13

Cholinesterase in the synaptic cleft

Question 14

If Acetylcholine is not broken down by Cholinesterase, where can it go?

Answer 14

Into synaptic vesicles

Question 15

What breaks down cytoplasmic noradrenaline?

Answer 15

Monoamine Oxide

Question 16

What is Noradrenaline synthesised from?

Answer 16

Tyrosine in the nerve terminal

Question 17

What are the 4 main classes of drugs which act on the ANS?

Answer 17

Nicotinic Cholinoceptor Antagonists
Muscarinic Cholinoceptor Agonists
Muscarinic Cholinoceptor Antagonist
Cholinesterase Inhibitors

Question 18

What type of drug is Pilocarpine?

Answer 18

Muscarinic Cholinoceptor Agonist

Question 19

What is Pilocarpine used for clinically?

Answer 19

Treatment of Glucomas

Question 20

What type of dug is Tubocurarine?

Answer 20

Nicotinic Cholinoceptor Antagonist used for muscle paralysis

Question 21

What type of drug can be used to treat Myasthenia Gravis?

Answer 21

Cholinesterase Inhibitors

Question 22

What Muscarinic Cholinoceptor Antagonist can be used for pupil dilation?

Answer 22

Tropicamide

Question 23

What is alpha Methyl-tyrosine?

Answer 23

A drug that completely blocks tyrosine hydroxylase so synthesis of noradrenaline is stopped

Question 24

When is alpha Methyl-tyrosine used clinically?

Answer 24

In Pheochromocytoma

Question 25

What is alpha-Methyl-DOPA?

Answer 25

It inhibits voltage operated calcium channels

Question 26

How does alpha Methyl DOPA inhibit VOCC?

Answer 26

Acts like noradrenaline, but poorly metabolised so accumulates in synaptic vesicles.
When these are released it acts on pre synaptic alpha 2 receptors which inhibit VOCC and reduce Ca2+mediated release

Question 27

What is CarbiDOPA?

Answer 27

Inhibits DOPA decarbocylase, but ONLY in the peripheral nervous system as it cannot cross the BBB

Question 28

How do Adrenergic Blocking Drugs work?

Answer 28

Reducing impulse conduction
Reduces Ca2+ mediated exocytosis
Reduces repletion of Noradrenaline

Question 29

How do Indirectly-acting Sympathomimetic Agents (IASAs) work?

Answer 29

They are taken into vesicles by Uptake 1.
The displaced Noradrenaline will leak into the synaptic cleft.
This can inhibit Noradrenaline degrading enzyme - MAO

Question 30

Give an example of Uptake 1 Inhibitors?

Answer 30

Tricyclic antidepressants. Exert action centrally, possible peripheral actions are side effects