Neuromuscular Junction

What is the meachnism of action of anticholinesterase drugs

Inhibit acetylchonlinesterase, increasing ACh levels at the NMJ.

What is acetylcholinesterase

Enzyme that breaks down ACh.

What is the effect of increased ACh at the NMJ

Continous binding to nicotninc receptors, resulting in influx of sodium and continous muscle stimulation.

What are anticholinesterase drugs indicated for

Treatment of myasthenia gravis and reverse competitve neuromuscular blockade post surgery.

How do pre-synpatic drugs such as botulinum toxin act

They prevent ACh vesicles from fusing with the membrane, blocking ACh release.

What is the effect of blocking ACh release (Pre synaptic drugs)

Failure of neuromuscular transmission causing flaccid paralysis.

How do competitive neuromuscular blocking drugs work

They competitvely bind to nicotninc receptors without activating them, preventing ACh from binding.

How can competitive neuromusuclar blockade be reversed

With anticholinesterase drugs that increase ACh levels.

How do depolarising neuromuscular blocking drugs work.

Attaches to N2 receptor and causes depolarisation of post-synpatic memebrane. These drugs stay bound longer than ACh, therefore the mm cannot replorise leading to flaccid paralysis.

What is initially seen with depolarising blockers

Transient mm fasiculations.

What are competitive neuromuscular blocking drugs indicated for

Relaxing vocal chords to facilitate endotrachial intubation.

What are depolarising neuromuscular blocking drugs indicated for

Emergency endotrachial intubation due to rapid onset.

Name 4 types of drugs that act on the neuromuscular junction

Anticholinesterase
Pre-synpatic
Competitive neuromuscular blocking
Depolarising neuromuscular blocking