Effect of altitude on brain intracellular pH and inorganic phosphate levels.
Normal brain activity is associated with task-related pH changes. Although central nervous system syndromes associated with significant acidosis and alkalosis are well understood, the effects of less dramatic and chronic changes in brain pH are uncertain. One environmental factor known to alter brain pH is the extreme, acute change in altitude encountered by mountaineers. However, the effect of long-term exposure to moderate altitude has not been studied. The aim of this two-site study was to measure brain intracellular pH and phosphate-bearing metabolite levels at two altitudes in healthy volunteers, using phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS). Increased brain pH and reduced inorganic phosphate (Pi) levels were found in healthy subjects who were long-term residents of Salt Lake City, UT (4720ft/1438m), compared with residents of Belmont, MA (20ft/6m). Brain intracellular pH at the altitude of 4720ft was more alkaline than that observed near sea level. In addition, the ratio of inorganic phosphate to total phosphate signal also shifted toward lower values in the Salt Lake City region compared with the Belmont area. These results suggest that long-term residence at moderate altitude is associated with brain chemical changes.
The Brain Institute, University of Utah, Salt Lake City, Utah, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT, USA. Electronic address: Xianfeng.Shi@hsc.utah.edu.
Xian-Feng
XF
Shi
The Brain Institute, University of Utah, Salt Lake City, Utah, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT, USA.
Paul J
PJ
Carlson
The Brain Institute, University of Utah, Salt Lake City, Utah, USA.
Tae-Suk
TS
Kim
The Brain Institute, University of Utah, Salt Lake City, Utah, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT, USA.
Young-Hoon
YH
Sung
The Brain Institute, University of Utah, Salt Lake City, Utah, USA.
Tracy L
TL
Hellem
The Brain Institute, University of Utah, Salt Lake City, Utah, USA.
Kristen K
KK
Fiedler
Department of Radiology, University of Utah, Salt Lake City, UT, USA.
Seong-Eun
SE
Kim
Brain Imaging Center, McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA, USA.
Breanna
B
Glaeser
Brain Imaging Center, McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA, USA.
Kristina
K
Wang
Brain Imaging Center, McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA, USA.
Chun S
CS
Zuo
Department of Radiology, University of Utah, Salt Lake City, UT, USA.
Eun-Kee
EK
Jeong
The Brain Institute, University of Utah, Salt Lake City, Utah, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT, USA; VISN 19 Mental Illness Research, Education and Clinical Center (MIRECC), Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.
Perry F
PF
Renshaw
The Brain Institute, University of Utah, Salt Lake City, Utah, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT, USA; VISN 19 Mental Illness Research, Education and Clinical Center (MIRECC), Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA.
Douglas G
DG
Kondo
D000328:Adult; D000531:Altitude; D001921:Brain / Q000378:metabolism*; D003287:Contrast Media; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008404:Massachusetts; D010710:Phosphates / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism; D010759:Phosphorus Isotopes; D012016:Reference Values; D014589:Utah
D003287:Contrast Media; D010710:Phosphates; D010759:Phosphorus Isotopes; D010758:Phosphorus
Altitude; Hypoxia; Spectroscopy