Question

Compare and contrast the mechanisms of actions of nondepolarizing and depolarizing neuromuscular blocking agents, and state how these actions affect using one class, rather than the other, in specified clinical situations.

Answer 1

The is an influx of calcium diffuse info the cell when the action potential depolarized the nerve terminal. This facilitates release of acetylcholine. This binds to the cholinergic receptors which depolarizes causing an action potential which activates sodium channels. Depolarizing muscle relaxant acts as acetylcholine receptor agonist that is they bind to the receptors and generate an action potential. There is an extended depolarization because they cannot be metabolized by acetylcholinesterase. As there is further binding the muscle cannot repolarize. Nondepolarizing muscle relaxant act as competitive antagonists. They bind with the acetylcholine receptors but do not open the channels and prevent further binding. Succinylcholine is a Depolarizing agent.