Department of Anesthesiology

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Divergent effects of anesthetics on lipid bilayer properties and sodium channel function.

TitleDivergent effects of anesthetics on lipid bilayer properties and sodium channel function.
Publication TypeJournal Article
Year of Publication2017
AuthorsHerold KF, Andersen OS, Hemmings HC
JournalEur Biophys J
Volume46
Issue7
Pagination617-626
Date Published2017 Oct
ISSN1432-1017
KeywordsAnesthetics, General, Animals, Gramicidin, Humans, Ion Channel Gating, Lipid Bilayers, Sodium Channels
Abstract

General anesthetics revolutionized medicine by allowing surgeons to perform more complex and much longer procedures. This widely used class of drugs is essential to patient care, yet their exact molecular mechanism(s) are incompletely understood. One early hypothesis over a century ago proposed that nonspecific interactions of anesthetics with the lipid bilayer lead to changes in neuronal function via effects on membrane properties. This model was supported by the Meyer-Overton correlation between anesthetic potency and lipid solubility and despite more recent evidence for specific protein targets, in particular ion-channels, lipid bilayer-mediated effects of anesthetics is still under debate. We therefore tested a wide range of chemically diverse general anesthetics on lipid bilayer properties using a sensitive and functional gramicidin-based assay. None of the tested anesthetics altered lipid bilayer properties at clinically relevant concentrations. Some anesthetics did affect the bilayer, though only at high supratherapeutic concentrations, which are unlikely relevant for clinical anesthesia. These results suggest that anesthetics directly interact with membrane proteins without altering lipid bilayer properties at clinically relevant concentrations. Voltage-gated Na+ channels are potential anesthetic targets and various isoforms are inhibited by a wide range of volatile anesthetics. They inhibit channel function by reducing peak Na+ current and shifting steady-state inactivation toward more hyperpolarized potentials. Recent advances in crystallography of prokaryotic Na+ channels, which are sensitive to volatile anesthetics, together with molecular dynamics simulations and electrophysiological studies will help identify potential anesthetic interaction sites within the channel protein itself.

DOI10.1007/s00249-017-1239-1
Alternate JournalEur. Biophys. J.
PubMed ID28695248
PubMed Central IDPMC5693657
Grant ListR01 GM058055 / GM / NIGMS NIH HHS / United States
HE4554/5-1 / / Deutsche Forschungsgemeinschaft / United States
GM058055 / / National Institute of General Medical Sciences / United States
GM021347 / / National Institute of General Medical Sciences / United States