Theories of Narcosis

TWO simple observations limit the possible explanations of how anesthetics act. The first concerns the rate at which anesthesia may be achieved. Anesthetics can induce unconsciousness within seconds, and, similarly, awakening can be rapid after discontinuation of anesthesia. This observation rules out long-term biochemical changes as a basis for narcosis. Thus, the theories that survive suggest physical perturbations or alterations of short-term biochemical events.The second observation concerns the varied nature of anesthetic compounds. Xenon, nitrous oxide, diethyl ether, and halothane all induce general anesthesia. The structural diversity of such compounds suggests that anesthetics do not act at a single . . .