Argon - a narcotic?

Bill Perkins perkinsw at
Sun Jan 2 11:25:36 EST 1994

> I'm not a medical expert, but I seem to recall reading many years ago
> somewhere (Popular Mechanics?) that the mechanism of action of the
> noble gases in causing anesthesia is that they raise the freezing
> temperature of water in the body to body temperature  via a colligative
> effect.  This, in turn, leads to the formation of ice crystals in the
> small blood vessels, reducing circulation.  Anesthesia follows by
> hypoxia.
> Sounds awful.
> Perhaps a physicist could confirm/refute the truth of this effect of
> noble gases on water?
> Bill Park
> =========
> -- 
> Grandpaw Bill's High Technology Consulting & Live Bait, Inc.

I'm unable to e-mail to you directly and apologize for this posting if it
seems inappropriate for this newsgroup.

My compliments on your memory! The clathrate theory of anesthesia put
forward by Linus Pauling (Science 134:15, 1961) and S.L. Miller (Proc Natl
Acad Sci USA 47: 1515, 1961) to which you allude was refuted more than 20
years ago. We still don't know how anesthetics work, but we do know that
this is not the mechanism. 

Anesthesia and hypoxia are different in that one reduces brain metabolism
primarily, whereas hypoxia reduces metabolism by reducing the supply of
oxygen. Hypoxia, if sustained, results in permanent damage to tissues,
whereas anesthetics reversibly decrease tissue metabolism.

Noble gases in solution do indeed form hydrates (i.e. the noble gas binds
water in something analogous to a ligand field). The correlation between
this property and anesthetic potency is, however, inconsistent.

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