Editing Action potential (section)

===Muscular action potentials===
{{Main|Neuromuscular junction|Muscle contraction}}

The action potential in a normal skeletal muscle cell is similar to the action potential in neurons.{{sfn|Ganong|1991|pp=59–60}} Action potentials result from the depolarization of the cell membrane (the [[sarcolemma]]), which opens voltage-sensitive sodium channels; these become inactivated and the membrane is repolarized through the outward current of potassium ions. The resting potential prior to the action potential is typically −90mV, somewhat more negative than typical neurons. The muscle action potential lasts roughly 2–4&nbsp;ms, the absolute refractory period is roughly 1–3&nbsp;ms, and the conduction velocity along the muscle is roughly 5&nbsp;m/s. The action potential releases [[calcium]] ions that free up the [[tropomyosin]] and allow the muscle to contract. Muscle action potentials are provoked by the arrival of a pre-synaptic neuronal action potential at the [[neuromuscular junction]], which is a common target for [[neurotoxin]]s.<ref name=Newmark group=lower-alpha />