General anesthetics and molecular mechanisms of unconsciousness.

The term ‘‘anesthesia’’ was originally used by the ancient Greek surgeon Dioscorides and resurrected by Dr Oliver Wendell Holmes to describe the insensible state produced by inhalation of ether. The goals of general anesthesia include amnesia, unconsciousness (also termed hypnosis), and immobilization. By definition, general anesthetics reversibly produce all 3 of these therapeutic effects. General anesthetic drugs include inhaled gases and intravenous agents. Other classes of drugs may be used by anesthetists to achieve specific clinical goals during surgery. For example, anesthetists often use drugs that selectively inhibit neuromuscular transmission to reduce patient movement and facilitate surgery. Benzodiazepines may be used to provide anxiolysis and anterograde amnesia, and opioids provide analgesia (an action that is produced by only a few general anesthetics). However, among the many drugs used by anesthetists, general anesthetics are uniquely used to produce unconsciousness.