This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.107.120493v1 94/11/4282    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Google Scholar Articles by Roth, R. Articles by Eisenberg, R. E. PubMed PubMed Citation Articles by Roth, R. Articles by Eisenberg, R. E.

Bubbles, Gating, and Anesthetics in Ion Channels

Roland Roth ^*, Dirk Gillespie , Wolfgang Nonner  and Robert E. Eisenberg 

^* Max-Planck Institut für Metallforschung, Stuttgart, Germany, Institut für Theoretische und Angewandte Physik, Universität Stuttgart, Stuttgart, Germany; Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois; and Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, Florida

Correspondence: Address reprint requests to Robert S. Eisenberg, Tel.: 312-942-6467; E-mail: beisenbe{at}rush.edu.

We suggest that bubbles are the bistable hydrophobic gates responsible for the on-off transitions of single channel currents. In this view, many types of channels gate by the same physical mechanism—dewetting by capillary evaporation—but different types of channels use different sensors to modulate hydrophobic properties of the channel wall and thereby trigger and control bubbles and gating. Spontaneous emptying of channels has been seen in many simulations. Because of the physics involved, such phase transitions are inherently sensitive, unstable threshold phenomena that are difficult to simulate reproducibly and thus convincingly. We present a thermodynamic analysis of a bubble gate using morphometric density functional theory of classical (not quantum) mechanics. Thermodynamic analysis of phase transitions is generally more reproducible and less sensitive to details than simulations. Anesthetic actions of inert gases—and their interactions with hydrostatic pressure (e.g., nitrogen narcosis)—can be easily understood by actions on bubbles. A general theory of gas anesthesia may involve bubbles in channels. Only experiments can show whether, or when, or which channels actually use bubbles as hydrophobic gates: direct observation of bubbles in channels is needed. Existing experiments show thin gas layers on hydrophobic surfaces in water and suggest that bubbles nearly exist in bulk water.

This article has been cited by other articles:

				E. I. Eger II, D. E. Raines, S. L. Shafer, H. C. Hemmings Jr, and J. M. Sonner Is a New Paradigm Needed to Explain How Inhaled Anesthetics Produce Immobility? Anesth. Analg., September 1, 2008; 107(3): 832 - 848. [Abstract] [Full Text] [PDF]

				B. Eisenberg Engineering channels: Atomic biology PNAS, April 29, 2008; 105(17): 6211 - 6212. [Full Text] [PDF]