Relationship between extracellular magnesium ion and general anesthetic actions

Magnesium ion (Mg²⁺) is involved in important processes as modulation of ion channels, receptors, neurotransmitter release and cell excitability in the central nervous system (CNS). Although previous reports suggested that Mg²⁺ per se could not produce anesthesia or analgesia, Mg²⁺ could modify the actions of volatile anesthetics in CNS. It has been reported that serum Mg²⁺ concentration is decreased by infusion of magnesium-free solution during general anesthesia, and that the alteration of CSF Mg²⁺ concentration is found to be correlated with serum Mg²⁺. Taken together, it might be possible that Mg²⁺-dependent modification of volatile anesthetic actions can take place during clinical anesthesia. Consequently, we recommend that extracellular Mg²⁺ concentration should be kept appropriately during general anesthesia.