Solitons in Biology A Possible Mechanism for General Anesthesia

T he first general anesthesia for human surgery was administered at the Massachusetts General Hospital in Boston in 1846. The patient was put to sleep by breathing diethyl ether from a glass vesicle. and the surgeon quickly dissected a tumor located under the jaw. After completing the operation the surgeon remarked to his audience, “Gentlemen, this is no humbug. ” Since this first successful demonstration of diethyl ether. researchers have discovered well over twenty drugs that induce general anesthesia. These drugs have highly diverse chemical structures and physical properties and, as a whole, lend little insight into their mechanism of action. In order to overcome this perplexity, H. Meyer and E. Overton (about the year 1900) originally proposed that anesthetic potency could be related to lipid volubility. They showed that stronger anesthetic agents were more oil-soluble than weaker ones and used this relationship to argue that anesthetics insert into the lipid bilayer and thereby expand its volume. More recent theories along this line have suggested that the expanded lipid bilayer compresses intrinsic membrane proteins and thereby disturbs normal protein shape and function. These theories have suggested also that the membrane-bound anesthetic molecules “fluidize” the lipid bilayer. This increased fluidity, in turn, alters the permeability of the membrane. While these popular ideas might be applicable to agents that are both volatile and highly lipid-soluble (oil-to-gas partition coeffi-