Neuromuscular Blockade

Question 1

What is the order of skeletal muscle paralysis in neuromuscular blockade?

Answer 1

Extrinsic muscles of eye paralysed first, then small muscles of face, hands, and finally pharynx and respiratory muscles

Question 2

How can we inhibit the synthesis of acetylcholine?

Answer 2

Inhibit choline acetyltransferase (normally this enzyme synthesises ACh)

Question 3

What does the botulin toxin do?

Answer 3

Blocks release of ACh, resulting in paralysis

Question 4

What are the features of non-depolarising blockers?

Answer 4

. Competitively block AChR
. Reversed by anticholinesterases
. Slower onset, longer duration

Question 5

What are the features of depolarising blockers?

Answer 5

. Persistently activate AChRs, which means the VG sodium ion channels can’t open in response to brief depolarisation
. Rapid onset and offset, short duration (good for intubation)