lecture 5 - neuromuscular blockers

Question 1

How is ACh transported?

Answer 1

In vesicles

Question 2

What enzyme breaks down ACh at the neuromuscular junction?

Answer 2

ACh esterase

Question 3

What are the different ways that neuromuscular blockers can work at neuromuscular junctions?

Answer 3

1. presynaptic inhibition of ACh release
2. inhibiton of AChE to prevent ACh reuptake
3. blocking ACh postsynaptically

Question 4

What are the 2 ways that postsynaptic neuromuscular block can be achieved?

Answer 4

1. Blocking ACh receptors (non-depolarising block)
2. Over-activating ACh receptors (depolarising block)

Question 5

Which type of postsynaptic neuromuscular block can be rapidly reversed, and why?

Answer 5

Non-depolarising - give ACh esterase inhibitors to increase ACh in synaptic cleft

Question 6

What is the main application for non-depolarising neuromuscular blockers?

Answer 6

Surgery - general anaesthetic

Question 7

Why do depolarising neuromuscular blockers cause muscle spasm before paralysis?

Answer 7

Because they work by overloading ACh receptors, which initially causes muscle activation before the receptor becomes desensitised.