Through extensive studies conducted by Meltzer, Auer and other investigators, it has been established, among many other important facts, that injections of magnesium salts produce anesthesia accompanied by a loss of reflexes, muscle tonus, and inhibition of the convulsions produced in tetanus. The effects are said to be paralysis of nerve cells, without preceding excitation, slight lowering of blood-pressure and shallow respiration.
The anesthetic dose, it was assumed, exercised an action directly on the nervous system, causing temporary sensory and motor depression, in that the nerve-cells of the cortex and centers in the medulla oblongata were affected. Furthermore, by local application of the magnesium solutions to the nerve trunks the conductivity of the nerve impulse is interrupted, while the contractile power of the muscle is not abolished by an anesthetic dose, since strychnin administered to an animal while under anesthesia caused convulsions to appear.
In considering the above facts, it
HYNDMAN HF, MITCHENER WE. THE INFLUENCE OF MAGNESIUM SULPHATE ON THE MOTOR CELLS OF THE CEREBRAL CORTEX. JAMA. 1910;55(4):281-282. doi:10.1001/jama.1910.04330040017004