X-Message-Number: 29610
Date: Tue, 26 Jun 2007 13:50:35 -0700 (PDT)
From: 
Subject: H2S protects against hypoxia

[Treating terminal patients with trace amounts of hydrogen sulfide may
significantly reduce the accumulation of brain damage that occurs during
subsequent cryonic procedures.]

Shock. 2007 Apr;27(4):370-2.
Suspended animation-like state protects mice from lethal hypoxia.
    Blackstone E, Roth MB. Molecular and Cellular Biology Program,
University of Washington, Seattle, Washington, USA.
Joseph Priestley observed the high burn rate of candles in pure oxygen and
wondered if people would "live out too fast" if we were in the same
environment. We hypothesize that sulfide, a natural reducer of oxygen that
is made in many cell types, acts as a buffer to prevent unrestricted oxygen
consumption. To test this, we administered sulfide in the form of hydrogen
sulfide (H2S) to mice (Mus musculus). As we have previously shown, H2S
decreases the metabolic rate of mice by approximately 90% and induces a
suspended animation-like state. Mice cannot survive for longer than 20 min
when exposed to 5% oxygen. However, if mice are first put into a suspended
animation-like state by a 20-min pretreatment with H2S and then are exposed
to low oxygen, they can survive for more than 6.5 h in 5% oxygen with no
apparent detrimental effects. In addition, if mice are exposed to a 20-min
pretreatment with H2S followed by 1 h at 5% oxygen, they can then survive
for several hours at oxygen tensions as low as 3%. We hypothesize that prior
exposure to H2S reduces oxygen demand, therefore making it possible for the
mice to survive with low oxygen supply. These results suggest that H2S may
be useful to prevent damage associated with hypoxia.
PMID: 17414418

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