Succinylcholine prevents bronchospasm by:

 # Succinylcholine prevents bronchospasm by:

A. Depolarising block

B. Direct muscle relaxation

C. Centrally acting muscle relaxation

D. Dual action

The correct answer is A. Depolarising block.

A depolarizing neuromuscular blocking agent, succinylcholine adheres to post-synaptic cholinergic receptors of the motor endplate, inducing continuous disruption that results in transient fasciculations or involuntary muscle contractions and subsequent skeletal muscle paralysis. Following pharmacological onset, further neuromuscular transmittance across the neuromuscular junction is interrupted, given the medication dosage is sufficient and remains bound to the cholinergic receptor sites of the motor endplate. Depolarization of the postjunctional membrane deactivates sodium avenues resulting in inhibited responses to acetylcholine normally released. The mechanism of action is apparent within 60 seconds of intravenous administration and continues up to 360 seconds or 6 minutes.