Cholinergic Pharmacology Flashcards Preview

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Flashcards in Cholinergic Pharmacology Deck (63)
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1
Q

What consists of the CND

A

Brain and Spinal Cord

2
Q

Two parts of the PNS

A

Somatic (NMJ)

Autonomic

3
Q

What chemical messengers are found in Somatic

A

ACh

4
Q

What chemical messengers are found in autonomic

A

ACh and Noradrenaline

5
Q

What chemical messenger acts in the Parasympathetic pathway

A

ACh

6
Q

What neurotransmitter works in the sympathetic pathways

A

Noradrenaline

7
Q

What can cholinergic receptors be categorised as

A

Nicotinic

Muscarinic

8
Q

What type of receptor is Nicotinic

A

Ion channel

9
Q

What type of receptor is Muscarinic

A

G-protein couples

10
Q

Where are muscarinic receptors found

A

Parasympathetic system

11
Q

Length of sympathetic preganglionic fibres vs parasympathetic

A

Sympathetic - shorter

Parasympathetic - longer

12
Q

Why are sympathetic preganglionic shorter

A

Because the ganglia are closer to the spinal cord

13
Q

Why are parasympathetic postganglionic fibres shorter

A

They synapse close to the target organ

14
Q

What does ACh bind to in the somatic NS

A

Nicotinic receptors at the neuromuscular junction

15
Q

Describe the processes that take place at the NMJ

A
  1. Acetyl CoA reacts with Choline to give ACh
  2. ACh stored in vesicles
  3. Vesicles fuses with membrane on pre-synapse
  4. ACh binds to Nicotinic cholingeric receptor
  5. Acetylcholinesterase breaks ACh to Choline and Acetate
16
Q

Enzyme that catalyses process of choline + Acetyl CoA -> ACh

A

CAT (Choline acetyl transferase enzyme)

17
Q

How does Botulinum Toxin effect the NMJ

A

Inhibits ACh vesicle release = paralysis by using proteases to degrade vesicle proteins

18
Q

What two reasons do we use Botox for

A
  1. Cosmetic

2. Spasticity

19
Q

Name a competitive NAChR antagonist

A
  1. Tubocurarine
20
Q

How does Tubocurarine function

A
  1. Acts as a neuromuscular blockade by binding to 2 nicotinic ending sites preventing binding of ACh
21
Q

Why do we give Tubocurarine

A

Has a muscle relaxant effect

2. Result in being conscious but aware of pain and paralysed

22
Q

How do we reverse the block effect of Tubocurarine

A

Sugammadex

23
Q

How does Sugammadex reverse block of Tubocurarine

A

Selective relaxant binding agent that encapsulates the blocker thereby preventing it from binding

24
Q

Structure of Suxamethonium

A

2ACh stuck together

25
Q

How does Suzamethonium effect the NMJ

A

Desensitises the receptor causing paralysis of skeletal muscle

26
Q

How fast does Suxamethonium act

A

Fast and for short duration

27
Q

Why does Suxamethonium stay in the NMj for a while

A

Poor substrate for ACH esterase can only be broken down by plasma cholinesterase

28
Q

Name a reversible ACh esterase inhibitor

A

Neostigmine

29
Q

How does Neostigmine work

A

Blocks Cholinesterase increasing ACh at the synaptic cleft

Remains for longer and stimulation lasts longer

30
Q

When do we prescribe Neostigmine

A

Myasthenia Gravis - alors ACh to remain longer resulting in a stronger response

31
Q

What is Myasthenia Gravis

A

Immune System produces antibodies against nAChR resulting in less receptors and weak skeletal muscles= response

32
Q

How do irreversible inhibitors effect NMJs

A

Inhibit ACh Esterase causing ACh to build up

Twitching, severe weakness and paralysis at NMJ

33
Q

How does irreversible inhibition effect mAChR

A
Salivation
Defecation 
Urination 
Bradycardia
Hypotension
34
Q

How does ACh accumulation from irreversible inhibition effect CNS

A

Confusion
Loss of reflexes
Convulsions
Coma

35
Q

Role of the autonomic nervous system

A

Fine tunes function of organs

36
Q

Role of Pilocarpine

A

Stimulates saliva in patients with dry mouth

Causes constrictor muscle and ciliary muscles to contract (miosis)
Improved filtration of aqueous fluid
Lowers intraocular pressure

37
Q

What is Pilocarpine an agonist of

A

M3 (partial agonist)

38
Q

Define miosis

A

Excessive constriction of pupil

39
Q

When do we give Pilocarpine for adjusting intraocular pressure

A

For Glaucoma

40
Q

What receptors mediate the parasympathetic pathway in the lungs

A

M3

41
Q

What happens during excessive M3 receptor activation in the lung

A

Bronchoconstriction

42
Q

Where is bronchoconstriction mediated by M3 seen

A

COPD

Asthma

43
Q

What two types of antagonists do we have for M3 receptors in the lung

A

Ipratopium (short acting) and tiotropium (Long acting)

these act as bronchodilators

44
Q

Each action in the bladder

A

Contraction of the bladder

45
Q

Result of bladder agonist

A

More bladder contraction (urinary retention)

46
Q

Result of using a bladder antagonist

A

Relaxes bladder

47
Q

Example of a bladder agonist

A

Bethanechol

48
Q

Example of a bladder antagonist

A

Oxynutinin

49
Q

How does ACh effect the GI tract

A

Increase GI motility

50
Q

What are mebeverine and scopolamine examples of

A

Gi antagonists

51
Q

Why would we prescribe mebeverine and scopolamine

A

Irritable Bowel Syndrome

52
Q

What is the adverse effects of muscarinic agonists

A
D- diarrhoea
U- rination 
M- iosis
B- Radycardia
E- mesis
L- agrimation 
S- alivation
53
Q

What is a competitive antagonist at the nAChR at the autonomic ganglia

A

Hexamethonium

54
Q

How does hexamethonium work

A

Blocks both the parasympathetic and sympathetic divisions of the autonomic nervous system

55
Q

Does hexamethonium effect the NMJ

A

No

56
Q

Four effects of parasympathetic autonomic block

A
  1. Secretions reduced
  2. Constipation
  3. Urinart retention
  4. Blurred vision
57
Q

What is a sympathetic block a marker of at the autonomic level

A

Hypotension

58
Q

When is hexamethonium given

A

As an antihypertensive

59
Q

What does ACh regulate in the brain

A

Vomiting centre

60
Q

What drug is given for motion sickness treatment and why

A

Scopolamine (anti-muscarininc)

61
Q

How do we treat Parkinsons

A

Benxatropine blocks reuptake of ACh and increases dopamine at cleft

62
Q

Why does Alzheimers occur

A

Lack of cholinergic neurones and reduction in ACh

63
Q

How do we treat Alzheimers

A

Donepezil to inhibit ACh esterase increasing ACh in CNS (only works in CNS)

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