[Anesthetic mechanisms in the spinal cord].

The essential elements of anesthesia are : hypnosis, amnesia, analgesia, immobility, and inhibition of untoward reflexes. The spinal cord is responsible for the latter three. Suppression of excitatory transmission and stimulation of inhibitory transmission are the anesthetic mechanisms in the spinal cord. Each anesthetic, however, has a unique effect on the transmission systems in the spinal cord. Some exclusively suppress excitatory transmission or stimulate inhibitory transmission, and others have a dual effect. The minimum alveolar/anesthetic concentration (MAC) is spinally mediated. Furthermore neurons in the ventral horn of spinal cord seem to be more depressed by anesthetics than neurons in the dorsal horn of the spinal cord. The ventral spinal cord also has relation to spinal cord ischemia. Investigation of the neuroprotective effect against spinal ischemia as well as the anesthetic effect in the ventral spinal cord is a very important subject of research.