Rocuronium acts by competing for cholinergic receptors at the motor end-plate. This action is antagonized by acetylcholinesterase inhibitors, such as neostigmine and edrophonium. Rocuronium acts by competitively binding to nicotinic cholinergic receptors. The binding of vecuronium decreases the opportunity for acetylcholine to bind to the nicotinic receptor at the postjunctional membrane of the myoneural junction. As a result, depolarization is prevented, calcium ions are not released and muscle contraction does not occur. Evidence also suggests that nondepolarizing agents can affect ACh release. It has been hypothesized that nondepolarzing agents bind to postjunctional (“curare”) receptors and may therefore interfere with the sodium and potassium flux, which is responsible for depolarization and repolarization of the membranes involved in muscle contraction.