Anticholinergics (antimuscarinics)

Question 1

How many types of cholinergic receptors are there?

1 - 5
2 - 4
3 - 3
4 - 2

Answer 1

4 - 2

• muscarinic and nicotinic

Question 2

In the parasympathetic nervous system, which neurotransmitter is released at the preganglionic neuron at the pre-synapse?

1 - acetylcholine
2 - noradrenaline
3 - dopamine
4 - serotonin

Answer 2

1 - acetylcholine

Question 3

Acetylcholine is released at the preganglionic neuron. Which receptor does acetylcholine bind with at the post synapse of a neuron?

1 - nicotinic receptors
2 - adrenergic receptors
3 - muscarinic receptors
4 - GABA receptors

Answer 3

1 - nicotinic receptors

Question 4

In the parasympathetic nervous system, which neurotransmitter is released at the postganglionic neuron where it stimulates its target tissue/cells?

1 - acetylcholine
2 - noradrenaline
3 - dopamine
4 - adrenaline

Answer 4

1 - acetylcholine

• ACh is released at pre and post ganglionic neurons in parasympathetic nervous system

Question 5

At the post-ganglionic neuron acetylcholine is released at the where it comes into contact with target tissue/cells. Which receptor does acetylcholine bind with at the post synapse of a neuron?

1 - nicotinic receptors
2 - adrenergic receptors
3 - muscarinic receptors
4 - GABA receptors

Answer 5

3 - muscarinic receptors

Question 6

There are 5 types of muscarinic receptors M1-M5. M1, M3 and M5 all bind with the same GPCR, which one is this?

1 - Gaq
2 - Gai
3 - Gas

Answer 6

1 - Gaq
- M1 also has a little Gai and Gas

Question 7

There are 5 types of muscarinic receptors M1-M5. M2 and M4 all bind with the same GPCR, which one is this?

1 - Gaq
2 - Gai
3 - Gas

Answer 7

2 - Gai

Question 8

Gaq GPCR are present on alpha 1 receptors and become active when binding with acetylcholine. Organise the following intracellular pathway that occurs when these receptors become active?

1 - IP3 binds with the endoplasmic reticulum and opens Ca2+ channels, leading to increased intracellular Ca2+ and depolarisation
2 - pKC can then phosphorylate target proteins and induce cellular activity
3 - phospholipase C (PLC) becomes activated located in the cell membrane
4 - DAG binds protein kinase C (pKC) which becomes active due to increased Ca2+
5 - PLC cleaves hospholipid called phosphatidylinositol 4,5-bisphosphate (PIP2) forming inositol trisphosphate (IP3), which is soluble and diffuses freely in the cytoplasm, and the other part is diacylglycerol (DAG), bound to the cell membrane

Answer 8

3 - phospholipase C (PLC) becomes activated located in the cell membrane

5 - PLC cleaves hospholipid called phosphatidylinositol 4,5-bisphosphate (PIP2) forming inositol trisphosphate (IP3), which is soluble and diffuses freely in the cytoplasm, and the other part is diacylglycerol (DAG), bound to the cell membrane

1 - IP3 binds with the endoplasmic reticulum and opens Ca2+ channels, leading to increased intracellular Ca2+ and depolarisation

4 - DAG binds protein kinase C (pKC) which becomes active due to increased Ca2+

2 - pKC can then phosphorylate target proteins and induce cellular activity

Question 9

Muscarinic receptors M2 and M4 have Gai GPCR present. What is the function of the Gai GPCRs?

1 - accentuates the activity of adenylyl cyclase
2 - inhibits adenylyl cyclase
3 - inhibits phospholipase C
4 - inhibits phospho kinase C

Answer 9

2 - inhibits adenylyl cyclase

• essentially inhibits the intracellular pathway of Gas

Question 10

What is the main purpose of the muscarinic M3 receptors present on smooth muscle in the lungs?

1 - vasodilates smooth muscles
2 - increased permeability of epithelial cells
3 - reduced mucous secretion
4 - induces smooth muscle contraction

Answer 10

4 - induces smooth muscle contraction
- part of parasympathetic nervous system, so involved in rest

Question 11

The parasympathetic is more commonly known as the rest and digest system. Which if the following is NOT a common function of the parasympathetic system?

1 - reduces HR and CO
2 - reduces digestion and defection
3 - increases salivary, sweat and lacrimal secretions
4 - constriction of detrusor muscle, stimulating urination
5 - stimulates glycogenesis
6 - bronchoconstriction in lung
7 - increased brain stimulation

Answer 11

2 - reduces digestion and defection
- parasympathetic stimulates both

Question 12

Which of the following is the core anti-muscarinic that predominantly works on the cardiac, GIT and respiratory tract?

1 - atropine
2 - lidocaine
3 - adrenaline
4 - solifenacin

Answer 12

1 - atropine

Question 13

Atropine is the core anti-muscarinic that is indicated to treat bradycardia. What is the mechanism of action of this drug?

1 - binds alpha receptors on SN and inhibits SN conduction
2 - binds alpha receptors and inhibits Ca2+ release
3 - binds alpha receptors and inhibits K+ channels so increases HR
4 - binds and inhibits ACh from binding to alpha receptors and inhibits parasympathetic activity

Answer 13

4 - binds and inhibits ACh from binding to alpha receptors and inhibits parasympathetic activity

• reduces parasympathetic activity means HR will increase

Question 14

Which of the following is atropine indicated in the use of in relation to the GIT?

1 - coeliac disease
2 - crohns disease
3 - irritable bowel syndrome
4 - ulcerative colitis

Answer 14

3 - irritable bowel syndrome
- associated with increased peristalsis
- atropine would reduce GIT motility

Question 15

Due to the action of atropine, all of the following can be adverse events, EXCEPT which one?

1 - blurred vision
2 - urine retention (reduced detrusor muscle contraction)
3 - tachycardia
4 - diarrhoea
5 - drowsiness (M1 receptors in brain)
6 - confusion (M1 receptors in brain)

Answer 15

4 - diarrhoea
- inhibit bowel movements so cause constipation

Question 16

Caution should be taken when prescribing atropine the anti-muscarinic drug in all of the following EXCEPT which one?

1 - acute closure glaucoma
2 - arrhythmia (unless bradycardia)
3 - benign prostate enlargement due to risk of urinary retention
4 - constipation

Answer 16

4 - constipation

• can increase intra-occular pressure
• can cause arrhythmias, but if bradycardia they need it

Question 17

Adverse events may occur when prescribing atropine when prescribing it with which other drug class?

1 - glucocorticoids
2 - acetylcholinesterase inhibitors
3 - tricyclics
4 - NMDA receptor antagonist

Answer 17

3 - tricyclics
- block muscarinic receptors so have an anti-muscarinic effects

Question 18

Atropine is typically indicated in bradycardia and given IV. Typically what is the starting dose?

1 - 500ug
2 - 1mg
3 - 2mg
4 - 3mg

Answer 18

1 - 500ug
- start at 500ug and increase in steps of 500ug every 1-2 minute intervals up to 3mg
- essentially stop when an acceptable HR is secured

Question 19

Which of the following is the core anti-muscarinic that predominantly works on the urogenital track?

1 - atropine
2 - lidocaine
3 - adrenaline
4 - solifenacin

Answer 19

4 - solifenacin

Question 20

Solifenacin is the core anti-muscarinic that predominantly works on the urogenital track. This drug is indicated in patients with overactive bladders, causing increased urination. What is the mechanism of action of this drug?

1 - increases ACh binding to M3 receptors on detrusor muscle
2 - inhibits ACh binding with M3 receptors on detrusor muscle
3 - inhibits noradrenaline binding with Gaq receptors on detrusor muscle
4 - inhibits ACh binding with Gaq receptors on detrusor muscle

Answer 20

2 - inhibits ACh binding with M3 receptors on detrusor muscle

• ACh normally induces detrusor muscle contraction and helps urination

Question 21

Due to the action of Solifenacin, all of the following can be adverse events, EXCEPTy which one?

1 - blurred vision
2 - urine retention (reduced detrusor muscle contraction)
3 - tachycardia
4 - diarrhoea
5 - drowsiness (M1 receptors in brain)
6 - confusion (M1 receptors in brain)

Answer 21

4 - diarrhoea

• normally causes constipation due to reduced peristalsis

Question 22

Solifenacin is the core anti-muscarinic that predominantly works on the urogenital track. This drug is indicated in patients with overactive bladders, causing increased urination. Which of the following is Solifenacin contraindicated in the treatment of?

1 - IBS
2 - bradcardia
3 - diarrhoea
4 - UTI

Answer 22

4 - UTI

• can cause urinary retention
• so urinalysis is important to rule out UTI

Question 23

Solifenacin is the core anti-muscarinic that predominantly works on the urogenital track. This drug can cause cognitive effects, especially in patients with dementia and older patients. How does this drug cause cognitive impairments?

1 - increases NMDA receptor binding in brain
2 - increases ACh binding to M1 receptors in brain
3 - reduces ACh binding with M1 receptors in the brain
4 - all of the above

Answer 23

3 - reduces ACh binding with M1 receptors in the brain

Question 24

Caution should be taken when prescribing solifenacin the anti-muscarinic drug in all of the following EXCEPT which one?

1 - acute closure glaucoma
2 - arrhythmia (unless bradycardia)
3 - benign prostate enlargement due to risk of urinary retention
4 - constipation

Answer 24

4 - constipation

Question 25

Adverse events may occur when prescribing atropine when prescribing it with which other drug class?

1 - glucocorticoids
2 - acetylcholinesterase inhibitors
3 - tricyclics
4 - NMDA receptor antagonist

Answer 25

3 - tricyclics
- block muscarinic receptors so have an anti-muscarinic effects