title: Temperature dependence of thermodynamic activity in volatile anesthetics: correlation between anesthetic potency and activity.
abstract: Temperature dependence of the saturated concentration and the activity coefficient of anesthetics (1-propanol, diethyl ether, chloroform, and halothane) in water were evaluated using vapor pressure and H NMR measurement. We found that these physical values (quantities) correlate with anesthetic potencies estimated according to the thermodynamic equilibrium model. The anesthetic potency for hydrophilic anesthetic (diethyl ether) decreased with decreasing temperature because of the temperature specificity of this saturated concentration. In contrast, potencies of hydrophobic anesthetics (chloroform and halothane) increased with decreasing temperature because of the temperature specificity of those activity coefficients. By assuming that anesthetics interact with hydrated water of cell membranes, the temperature dependence of anesthetic potencies in vivo is qualitatively explicable.
authors.affiliation: Department of Life and Materials Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan. yamamoto.yasushi@nitech.ac.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Keijiro
authors.initials: K
authors.lastname: Taga
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kamaya
authors.forename: Issaku
authors.initials: I
authors.lastname: Ueda
mesh_terms: D000777:Anesthetics / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008954:Models, Biological; D015394:Molecular Structure; D011312:Pressure; D013329:Structure-Activity Relationship; D013696:Temperature; D013816:Thermodynamics; D014835:Volatilization
chemical_list: D000777:Anesthetics