Decamethonium is a depolarizing neuromuscular blocking agent. It is a partial agonist of muscle-type nicotinic acetylcholine receptors (nAChRs). Decamethonium activates α1β1-containing adult mouse muscle-type nAChRs expressed in X. laevis oocytes with an EC50 value of 40 μM using voltage clamp electrophysiology. It is also a nondepolarizing antagonist of neuronal-type nAChRs, inhibiting mouse α7-, α3β2-, α3β4-, and α4β2-containing receptors with IC50 values of 7.4, 405, 28, and 59 μM, respectively. Decamethonoium is a competitive antagonist of α4β2-containing nAChRs expressed in SH-EP1 cells (IC50 = 52 μM for the human receptor). It also inhibits electric eel acetylcholinesterase (AChE) and blocks electrically-evoked tibialis muscle twitches in anesthetized cats with ED95 values of 35 and 70 μg/kg for cats under chloralose and ether anesthesia, respectively. Formulations containing decamethonium have been used to induce paralysis during anesthesia.
