The enhancement of proton/hydroxyl flow across lipid vesicles by inhalation anesthetics.
When pH gradients are created across model lipid membranes, there is a well-documented electrogenic flow of protons, which results in the development of a transmembrane potential. As a result, protons come to electrochemical equilibrium across lipid vesicles within tens of minutes. The ability of a series of inhalation anesthetics to enhance the conduction of protons across model membranes was examined. When clinically relevant concentrations of halothane, isoflurane, enflurane, or chloroform were equilibrated with sonicated lipid vesicles, significant increases in the proton conduction were found. However, for even high anesthetic concentrations (above 8 MAC) of ether and cyclopropane, no increases in proton conduction could be detected. These results rule out a common mechanism for general anesthesia involving enhanced proton conduction across membranes.
Raines
D E
DE
Department of Chemistry, University of Virginia, Charlottesville 22901.
Cafiso
D S
DS
D000769:Anesthesia, Inhalation; D000777:Anesthetics / Q000494:pharmacology*; D002463:Cell Membrane Permeability; D004578:Electron Spin Resonance Spectroscopy; D006878:Hydroxides / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism*; D011522:Protons
D000777:Anesthetics; D006878:Hydroxides; D008051:Lipid Bilayers; D011522:Protons