Intermolecular Interactions and Anesthesia

Abstract

Recent theories of the mechanism of anesthesia concentrate on the perturbation exerted by anesthetics on the membrane of the nerve cell. Since there exists a good relationship between the lipid solubilities of anesthetics and their anesthetic potencies, it is usually assumed that they act through hydrophobic interactions in the lipid layers of the membrane. This leads to the hydrophobic site theory, which, in turn, is the basis of the unitary hypothesis implying that the mechanisms of action of all inhalational anesthetics are essentially the same. According to recent theories by Eyring et al. and by Changeux et al., anesthetics induce conformational changes in the lipids and/or proteins that constitute the nerve cell membrane, thereby changing its permeability to ions. Some molecular studies of fluorocarbon anesthetics are discussed. While hydrophobic interactions undoubtedly play an important role in the mechanism of anesthesia, polar interactions, including H-bonding and the perturbation of molecular associations, cannot be disregarded. Further theories of anesthesia will have to take this into account.