Neurochemical alterations in frontal cortex of the rat after one week of hypobaric hypoxia

Olena V. Bogdanova, Osama Abdullah, Shami Kanekar, Volodymyr B. Bogdanov, Andrew P. Prescot, Perry F. Renshaw
Behavioural Brain Research. 2014-04-01; 263: 203-209
DOI: 10.1016/j.bbr.2014.01.027

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Bogdanova OV(1), Abdullah O(2), Kanekar S(3), Bogdanov VB(4), Prescot AP(5), Renshaw PF(6).

Author information:
(1)Brain Institute, University of Utah, 383 Colorow Drive, Salt Lake City 84108,
UT USA. Electronic address: .
(2)Department of Bioengineering, University of Utah, 36 S. Wasatch Drive, Salt
Lake City 84112, UT USA.
(3)Brain Institute, University of Utah, 383 Colorow Drive, Salt Lake City 84108,
UT USA; Psychiatry Department, University of Utah, 383 Colorow Drive, Salt Lake
City 84108, UT USA.
(4)INRA, Nutrition et Neurobiologie Intégrée and University Bordeaux, Nutrition
et Neurobiologie Intégrée, UMR 1286, 146 rue Léo-Saignat, Bordeaux Cedex 33076,
France.
(5)Brain Institute, University of Utah, 383 Colorow Drive, Salt Lake City 84108,
UT USA; Department of Radiology, University of Utah, 30 North 1900 East, Salt
Lake City 84132, UT USA.
(6)Brain Institute, University of Utah, 383 Colorow Drive, Salt Lake City 84108,
UT USA; Psychiatry Department, University of Utah, 383 Colorow Drive, Salt Lake
City 84108, UT USA; VISN19 MIRECC Salt Lake City UAMC, 500 Foothill Drive, Salt
Lake City 84148, UT USA.

Residing at high altitude may lead to reduced blood oxygen saturation in the
brain and altered metabolism in frontal cortical brain areas, probably due to
chronic hypobaric hypoxia. These changes may underlie the increased rates of
depression and suicidal behavior that have been associated with life at higher
altitudes. To test the hypothesis that hypobaric hypoxia is responsible for
development of mood disorders due to alterations in neurochemistry, we assessed
depression-like behavior in parallel to levels of brain metabolites in rats
housed at simulated altitude. 32 female Sprague Dawley rats were housed either in
a hypobaric hypoxia chamber at 10,000 ft of simulated altitude for 1 week or at
local conditions (4500 ft of elevation in Salt Lake City, Utah). Depression-like
behavior was assessed using the forced swim test (FST) and levels of
neurometabolites were estimated by in vivo proton magnetic resonance spectroscopy
in the frontal cortex, the striatum and the hippocampus at baseline and after a
week of exposure to hypobaric hypoxia. After hypoxia exposure the animals
demonstrated increased immobility behavior and shortened latency to immobility in
the FST. Elevated ratios of myo-inositol, glutamate, and the sum of myo-inositol
and glycine to total creatine were observed in the frontal cortex of hypoxia
treated rats. A decrease in the ratio of alanine to total creatine was also
noted. This study shows that hypoxia induced alterations in frontal lobe brain
metabolites, aggravated depression-like behavior and might be a factor in
increased rates of psychiatric disorders observed in populations living at high
altitudes.

 

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