The actions of halogenated ethers on the ionic currents of the squid giant axon.

Abstract

The effects of fourteen halogenated ethers on the sodium and potassium currents of voltage-clamped squid giant axons have been examined. Effects under open-circuit were also studied. In voltage-clamped axons, the ethers tended to reduce potassium currents at least as much, if not more, than sodium currents. This finding distinguishes the halogenated ethers from many other general anaesthetics. Certain, but not all, halogenated ethers induced a pronounced maximum in potassium current traces as a function of time. This property can be formally described if an inactivation term is added to the Hodgkin-Huxley equation for potassium currents. Large shifts in the sodium-current inactivation parameter h infinity were produced in some instances. Two fully halogenated methyl ethyl ethers, known to produce convulsions in mice, depressed both sodium and potassium currents, but with a very slow time course of action. The electrophysiological effects of the halogenated ethers investigated appear to depend on the position and number of hydrogen bonds that can be formed.

• Authors: B W Urban, D A Haydon
• Journal: Proceedings of the Royal Society of London. Series B, Biological sciences (Proc R Soc Lond B Biol Sci) Vol. 231 Issue 1262 Pg. 13-26 (Jun 22 1987) ISSN: 0950-1193 [Print] England
• PMID: 2442763 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Ethers
• Halogens
• Ion Channels
• Sodium
• Potassium

Topics

• Animals
• Axons (drug effects)
• Decapodiformes
• Depression, Chemical
• Dose-Response Relationship, Drug
• Ethers (pharmacology)
• Halogens (pharmacology)
• In Vitro Techniques
• Ion Channels (drug effects)
• Potassium (metabolism)
• Sodium (metabolism)
• Structure-Activity Relationship