Contractile Phenomenon of Skeletal Muscle and Mechanisms of Action of Muscle Relaxants

Abstract

The physiologic and biochemical basis of neuromuscular transmission was discussed in the session. Neuromuscular blocking agents are used to improve conditions for tracheal intubation, to provide immobility during surgery, and to facilitate mechanical ventilation. The only depolarizing agent in use is succinylcholine. All other drugs available are non-depolarizing. The presynaptic release of acetylcholine is triggered by the influx of calcium through voltage-dependent calcium ion channels. Muscle relaxants compete with acetylcholine for the same binding sites. They interfere with normal function of the acetylcholine receptor binding site or with opening and closing of the receptor channel. This review highlights several specific aspects of neuromuscular transmission that are germane to pharmacology for neuromuscular paralysis.