Intracellular alkalosis during hypoxia in newborn mouse brain in the presence of systemic acidosis: a phosphorus magnetic resonance spectroscopic study.
We investigated the in vivo changes in cerebral energy metabolism and pHi in newborn mice noninvasively during 8 h of hypoxia with FiO2 = 5%, using phosphorus magnetic resonance spectroscopy continuously. The intracellular brain pH (pHi) increased from 7.20 +/- 0.03 to 7.36 +/- 0.03 (P < 0.05) at 1 h of hypoxia and then decreased gradually. On the other hand, the mixed arterial and venous blood pH decreased gradually during hypoxia, reaching a minimum value of 7.16 +/- 0.01 at the end of the hypoxia. There was no significant difference in PCO2 between control (47.4 +/- 0.8 mm Hg) and 1-h hypoxic (49.0 +/- 1.1 mm Hg) mice. The blood glucose concentration was significantly increased at 1 h of hypoxia. These results indicate that the alkaline shift in pHi during hypoxia was caused neither by systemic alkalosis due to hypocapnia nor hypoglycemia.
Mitsufuji
N
N
Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto First Red Cross Hospital, Japan.
Yoshioka
H
H
Tominaga
M
M
Okano
S
S
Nishiki
T
T
Sawada
T
T
D000138:Acidosis / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000471:Alkalosis / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001784:Blood Gas Analysis; D001786:Blood Glucose / Q000378:metabolism; D001923:Brain Chemistry / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D010759:Phosphorus Isotopes
D001786:Blood Glucose; D010710:Phosphates; D010759:Phosphorus Isotopes; D010725:Phosphocreatine; D000255:Adenosine Triphosphate