Autonomic nervous system 2

Question 1

What can happen to neurotransmitter in the pre-synaptic neurone?

Answer 1

Packaged into vesicles waiting to be released

Degraded

Question 2

What can happen to neurotransmitter after it has been released into the synaptic cleft?

Answer 2

Diffuses across synaptic cleft
binds to receptors on post-synaptic membrane

Inactivated by enzymes
breakdown products taken up by pre-synaptic neuurone

Binds to receptors on pre-synaptic membrane

Taken up by pre-synaptic neurone

Question 3

What is the reaction of acetylcholine synthesis?

Answer 3

Acetyl coA + choline —–> acetylcholine + coA

Question 4

What enzyme catalyses the reaction

Acetyl coA + choline —–> acetylcholine + coA

Answer 4

Choline acetyl transferase

Question 5

What is the reaction of acetylcholine degradation?

Answer 5

Acetylcholine —–> acetate + choline

Question 6

What enzyme catalyses the reaction

Acetylcholine —–> acetate + choline

Answer 6

Acetylcholinesterase

Question 7

How varied are nicotinic acetylcholine receptors?

Answer 7

Different nictonic acetylcholine receptors at autonomic nerve fibres ganglia and at neuromuscular junctions

Question 8

What are ganglion-blocking drugs?

Answer 8

Drugs that block nicotinic acetylcholine receptors specifically at autonomic nerve fibres ganglia

Question 9

How specific are muscarinic acetylcholine receptor agonists and antagonists?

Answer 9

Not very specific to the receptor subtypes M1, M2, M3 etc.

affect all of them

Question 10

What are the consequences of muscarinic acetylcholine receptor agonists not being specific?

Answer 10

Decreased heart rate

Bronchoconstriction

SLUDGE

Question 11

What does SLUDGE stand for?

Answer 11

Salivation

Lacrimation - eyes tearing up

Urination

Defecation

GI upset

Emesis - vomiting

Question 12

How is SLUDGE treated?

Answer 12

Muscarinic acetylcholine receptor antagonists

Question 13

What are the effects of acetylcholinesterase inhibitors?

Answer 13

Raise acetylcholine levels

enhance stimulation of muscarinic acetylcholine receptors

Question 14

What is the structure of sympathetic post-ganglionic neurons?

Answer 14

Axons are branched

lots of varicosities

Question 15

What is a varicosity?

Answer 15

Bulging of the axon

where synapses can form

Question 16

What is the starting molecule of noradrenaline synthesis?

Answer 16

Tyrosine

Question 17

What are the intermediate molecules of noradrenaline synthesis?

Answer 17

DOPA

Dopamine

Question 18

What catalyses the reaction

Tyrosine —–> DOPA?

Answer 18

Tyrosine hydroxylase

Question 19

What catalyses the reaction

DOPA —–> Dopamine

Answer 19

DOPA decarboxylase

Question 20

What catalyses the reaction

Dopamine —–> noradrenaline?

Answer 20

Dopamine B-hydroxylase

Question 21

Where does the reaction

Noradrenaline —–> adrenaline occur?

Answer 21

Adrenal medulla chromaffin cells

Question 22

What catalyses the reaction

Noradrenaline —–> adrenaline?

Answer 22

N-methyltransferase

Question 23

How is noradrenaline signalling in synapses terminated?

Answer 23

Noradrenaline is transported into the pre-synaptic neurone

Question 24

What are the different mechanisms of noradrenaline transport into the pre-synaptic neurone?

Answer 24

Uptake 1 - symporter moves noradrenaline along with sodium ions into pre-synaptic neurone

Uptake 2

Question 25

Which mechanism is largely responsible for noradrenaline transport into the pre-synaptic neurone

Answer 25

Uptake 1

Question 26

How is noradrenaline that’s not packaged into vesicles degraded?

Answer 26

Broken down by enzymes

Question 27

What enzyme breaks down noradrenaline?

Answer 27

Monoamine oxidase

Question 28

How specific are adrenoceptor agonists and antagonists?

Answer 28

Specific to the receptor subtype A1, A2, B1, B2 etc.