Intracellular pH Regulation of Normal Rat Brain: 31P-MRS Study

  • F. Ohta
  • K. Moritake
  • T. Kagawa
  • M. Fukuda
  • A. Fukuma
Conference paper
Part of the Acta Neurochirurgica book series (NEUROCHIRURGICA, volume 51)


Intracellular pH changes in rat brain tissue were investigated during low or high extracellular pH induced by acetazolamide or sodium bicarbonate, respectively. Intracellular pH was measured by 31P-MRS in the brain of spontaneously breathing rats under intraperitoneal sodium pentobarbital anaesthesia. Extracellular pH was calculated from the results of blood gas analysis. After intravenous injection of sodium bicarbonate (280 mg/kg), the extracellular pH rose significantly (p < 0.05) from 7.47 ± 0.06 to 7.82 ± 0.15 (mean ± SE). After administration of acetazolamide (50 mg/kg), the extracellular pH dropped significantly (p < 0.05) from 7.45 ± 0.02 to 7.34 ± 0.03. Despite the changes in extracellular pH, the intracellular pH of rat brain did not change significantly under either condition. The following four factors are thought to contribute to the maintenance of intracellular pH in the normal brain: 1) production and consumption of H+ by brain metabolism, 2) physicochemical buffering, 3) transmembrane transport of H+ and its equivalent, 4) compensatory adaptation of circulatory factors. These mechanisms are not disturbed in the brain of rats that are breathing spontaneously, because the cerebral circulation and energy metabolism are preserved in the normal range.


Cerebral Circulation Cereb Blood Flow Sodium Pentobarbital Anaesthesia Circulatory Factor Compensatory Adaptation 


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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • F. Ohta
    • 1
  • K. Moritake
    • 2
  • T. Kagawa
    • 1
  • M. Fukuda
    • 1
  • A. Fukuma
    • 1
  1. 1.Department of NeurosurgeryShimane Medical UniversityIzumoJapan
  2. 2.Department of NeurosurgeryShimane Medical UniversityIzumo 693Japan

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