Autonomic Nervous System 2 (session 8)

Question 1

What is the equation for ACh synthesis and which enzyme catalyses the reaction?

Answer 1

Acetyl CoA + choline -> ACh + coenzyme A

Catalyses by choline acetyltransferase (CAT)

Question 2

What is the equation for ACh degradation and which enzyme catalyses the reaction?

Answer 2

ACh -> acetate + choline

Acetyl)cholinesterase (AChE

Question 3

Which ganglion-blocking drug is used in hypertensive emergencies and to produce controlled hypotension during surgery?

Answer 3

Trimethaphan

Question 4

Which mAChR antagonist (M3) is used to treat overactive bladder and what is its main side effect?

Answer 4

Tolterodine

Dry mouth

Question 5

Which AChE inhibitor is used to treat myasthenia gravis?

Answer 5

Pyridostigmine

Question 6

Which AChE inhibitor is used to treat Alzheimer’s disease?

Answer 6

Donepezil

Question 7

Why is the usage of cholinergic drugs limited?

Answer 7

Unwanted side-effects due to lack of selectivity

Question 8

What side-effects is a non-selective muscarinic ACh receptor agonist likely to cause?

Answer 8

Decreased heart rate and cardiac output
Increased bronchoconstriciton and peristalsis
Increased sweating and salivation

Question 9

What does SLUDGE stand for (parasympathetic nervous system)?

Answer 9

Salivation 
Lacrimation
Urination 
Defecation 
GI upset (diarrhoea)
Emesis (vomiting)

Question 10

In which cases is SLUDGE encountered?

Answer 10

Drug overdose
Ingestion of magic mushrooms
Exposure to organophosphorous insecticides or nerve gases

Question 11

What are the symptoms of SLUDGE primarily due to?

Answer 11

Chronic (over-) stimulation of mAChR in organs and muscles innervated by parasympathetic nervous system

Question 12

What can treat SLUDGE? (2)

Answer 12

Atropine

Pralidoxime

Question 13

Which mAChR antagonists are used to treat asthma and COPD?

Answer 13

Ipratropium

Tiotropium

Question 14

How are NA actions terminated?

Answer 14

By re-uptake into the pre-synaptic terminal by a Na+ dependent, high affinity symport transporter.
NA not re-captured by uptake 1 ^ is taken up by a lower affinity, non-neuronal mechanism

Question 15

Within the pre-synaptic terminal, NA not taken up into vesicles is susceptible to metabolism by which two enzymes?

Answer 15

Monoamine oxidase (MAO)
Catechol-O-methyltransferase (COMT)

Question 16

Beta2-adrenoceptor-selective agonists are used in asthma to reverse what? And give an example of the beta2-adrenoceptor-selective agonist used in asthma

Answer 16

Bronchoconstriction

Salbutamol

Question 17

Which type of drugs are used to treat hypertension?

Answer 17

Alpha1 (eg doxazosin) and beta1-adrenoceptor-selective antagonists (eg atenolol)