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Three Compartments Model for the Bicarbonate Exchange of the Brain Extracellular Fluid with Blood and Cells

  • H. R. Ahmad
  • H. H. Loeschcke
  • H. H. Woidtke
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 99)

Abstract

Respiratory regulation is considered as one of the wellestablished feedback mechanisms serving the acid-base homeostasis of the brain extracellular fluid1,2. In addition to this, compensatory changes in bicarbonate of this fluid have been shown by a number of investigators to contribute towards the pH control of the brain extracellular fluid. The mechanisms responsible for the change of the extracellular bicarbonate are controversial. Both active and passive mechanisms have been postulated. It was proposed on the basis of high altitude studies that the existing disequilibrium would be due to active transport of either H+ or HCO 3 - across the blood brain barrier, and that this pump would protect CSF from acid-base derangements3,4. The conclusion of Severinghaus seems to be contradicted by others5, 6 who have reported no evidence for a precise regulation of the pH in cisternal or lumbar CSF during respiratory alkalosis in high altitude acclimatization. This question remains open as well as the question of how far the acid-base measurement in bulk CSF approximated the status in the brain extracellular fluid bathing the cells. Of special importance is the fact that the time course of changes in pH on the ventral surface of the medulla oblongata is not yet established7.

Keywords

Extracellular Fluid Metabolic Alkalosis Bicarbonate Concentration Glia Cell Respiratory Acidosis 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Loeschcke, H.H.: Control of the acid-base status of brain extracellular fluid by the ventilation. Clin. Physiol. (Tokyo) 1:156–l69, 1973.Google Scholar
  2. 2.
    Loeschcke, H.H.: Recent concepts of respiratory regulation. Wiener Klin. Wochenschr. 89:429–435, 1977.Google Scholar
  3. 3.
    Severinghaus, J.W., Mitchel, R.A., Richardson, B.W. and Singer, M.M.: Respiratory control at high altitude suggesting active transport regulation of CSF pH. J. Appl. Physiol. 18: 1155–1166, 1963.PubMedGoogle Scholar
  4. 4.
    Fencl, V., Miller, T.B. and Pappenheimer, J.R.: Studies on the respiratory response to disturbrances of acid-base balance with deduction concerning the ionic composition of cerebral interstitial fluid. Am. J. Physiol. 210:459–472, 1966.PubMedGoogle Scholar
  5. 5.
    Dempsey, J.A., Forster, H.V. and Dopico, G.A.: Ventilatory acclimatization to moderate hypoxemia in man. J. C1in. Invest. 53:1091–1100, 1974.CrossRefGoogle Scholar
  6. 6.
    Bouverot, P.: Arterial chemosensitivity and CSF acid-base status of awake dogs at low and high altitude: Acid-base Homeostasis of the Brain Extracellular Fluid and the Respiratory Control System. Edited by H.H. Loeschcke, Georg Thieme Verlag, Stuttgart, 1976.Google Scholar
  7. 7.
    Ahmad, H.R., Woidtke, H.H. and Loeschcke, H.H.: Transients of ventilation and pH in the brain extracellular fluid following a step change of end tidal PC02. Pflug. Arch. Suppl.368:70, 1977.Google Scholar
  8. 8.
    Siesjo, B.A. and Kjallquist, A.: A new theory for the regulation of the extracellular pH in the brain. Scand. J. C1in. Lab. Invest. 24:1-9, 1969.Google Scholar
  9. 9.
    Pavlin, E.G. and Hornbein, T.F.: Distribution of H+ and HCO3- between CSF and blood during respiratory acidosis in dogs. Am. J. Physiol. 228:1145–1148, 1975.PubMedGoogle Scholar
  10. 10.
    Hornbein, T.F. and Pavlin, E.G.: Distribution of H+ and HCO3- between CSF and blood during respiratory alkalosis in dogs. Am. J. Physiol. 228:4, 1975.Google Scholar
  11. 11.
    Pannier, J.L., Weyne, J. and Leusen, I.: The CSF/blood potential and the regulation of the bicarbonate concentration of CSF during acidosis in the cat. Life Sci. 10:287–300, 1971.CrossRefGoogle Scholar
  12. 12.
    Bledsoe, S.W. and Mines, A.H.: Effect of elevated plasma K+ on voltage difference and ionic distribution between CSF and blood. Fed. Proc. 34:357, 1975.Google Scholar
  13. 13.
    Woodbury, J.W.: Fluxes of H+ and HCO3- across frog skeletal muscle cell membrane. In: Alfred Benzon Symposium III. Ion Homeostasis of the Brain. Copenhagen, Munksgaard, 1971, pp. 270–284.Google Scholar
  14. 14.
    Ahmad, H.R., Berndt, J. and Loeschcke, H.H.: Non-respiratory mechanisms contributing to the acid-base homeostasis of the brain extracellular fluid. Pflug. Arch. Suppl. 72: 1975.Google Scholar
  15. 15.
    Ahmad, H.R., Berndt, J. and Loeschcke, H.H.: Bicarbonate exchange between blood and extracellular fluid and brain cells at maintained PC0 2. In: Acid-base Homeostasis of the Brain Extracellular Fluid and the Respiratory Control System. Edited by H.H. Loeschcke, Georg Thieme Verlag, Stuttgart, 1976.Google Scholar
  16. 16.
    Hasan, F.M. and Kazemi, H.: The dual contribution theory of regulation of CSF HC03 in respiratory acidosis. J. Appl. Physiol. 40:559–567, 1976.PubMedGoogle Scholar
  17. 17.
    Leusen, I. and Weyne, J.: Metabolic processes in the brain during respiratory and non-respiratory alkalosis and acidosis. In: Acid-base Homeostasis of the Brain Extracellular Fluid and the Respiratory Control System. Edited by H.H. Loeschcke, Georg Thieme Verlag, Stuttgart, 1976.Google Scholar
  18. 18.
    Loeschcke, H.H.: DC potential between CSF and blood. In: Ion Homeostasis of the Brain. Edited by B.K. Siesjo and S.C. Sørensen, Copenhagen, Munksgaard, 1971, pp. 77–96.Google Scholar
  19. 19.
    Siesjo, B.K. and Ponten, U.: The buffer capacity of brain tissue and of equivalent systems. N.Y. Acad. Sci. 133: 180–194, 1966.CrossRefGoogle Scholar
  20. 20.
    Weyne, J., Demeester, G. and Leusen, I.: Bicarbonate and chloride shifts in rat brain during acute and prolongedrespiratory acid-base changes. Arch. Internat. Physiol. Biochem. 76:415–433, 1968.CrossRefGoogle Scholar
  21. 21.
    Middendorf, T. and Loeschcke, H.H.: Approximative Berechnung der Pufferbase, einer Titrationsgeraden fur Proteine und der CO2-Dissoziationskurve des Gehirngewebes. Pflug. Arch. 349:1–8, 1974.CrossRefGoogle Scholar
  22. 22.
    Kazemi, H., Shore, N.S., Shih, V.E. and Shannon, D.C.: Brain organic buffers in respiratory acidosis and alkalosis. J. Appl. Physiol. 34:478, 1973.PubMedGoogle Scholar
  23. 23.
    Maren, T.H. and Broder, L.E.: The role of carbonic anhydrase in anion secretion in the CSF. J. Pharm. Exp. 172:196–202, 1970.Google Scholar
  24. 24.
    Reed, D.J., Woodbury, D.M. and Holtzer, R.L.: Brain oedema, electrolytes and extracellular space: Effect of trietyltin on brain and skeletel muscle. Arch. Neurol. 10:604–616, 1964.PubMedCrossRefGoogle Scholar
  25. 25.
    Loeschcke, H.H.: The apparent specificity of CO2 as a respiratory stimulus. Bull. Physiol.-Path. Respir. 10: 858–876, 1974.Google Scholar
  26. 26.
    Loeschcke, H.H.: A concept of the role of intracranial chemosensitivity. In: Respiratory Control and the Regulation of Ventilation. Edited by C.Mc C. Brooks, F.F. Kao and B.B. Lloyd, Oxford, Blackwell Scientific Publications, 1965, pp. 183–207.Google Scholar
  27. 27.
    Loeschcke, H.H. and Sugioka, K.: pH of cerebrospinal fluid in the cisterna magna and on the surface of the choroid plexus of the fourth ventricle and its effect on ventilation in experimental disturbances of acid-base balance. Transients and steady states. Pflug. Arch. 312:161–188, 1969.Google Scholar
  28. 28.
    Granholm, L. and Ponten, U.: The in vivo CO2 buffer curve of the intracellular space of cat cerebral cortex. Acta Neurol. Scand. 45:495–501, 1969.Google Scholar
  29. 29.
    Fencl, V.: Distribution of H+ and HCO3- in cerebral fluids. Alfred Benzon Symposium III. Ion Homeostasis of the Brain. Copenhagen, Munksgaard, 1971, pp. 175-188Google Scholar
  30. 30.
    Ahmad, H.R., Woidtke, H.H. and Loeschcke, H.H.: Fast exchange of bicarbonate ions between blood and the extracellular fluid of the medulla in acute metabolic alkalosis. Proc. Int. Physiol. Sci. XXVII:21, 1977.Google Scholar
  31. 31.
    Bleich, H.L., Berkmann, P.M. and Schwartz, W.B.: The response of cerebrospinal fluid composition to sustained hypercapnia. J. Clin. Invest. 43:11–16, 1964.PubMedCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1978

Authors and Affiliations

  • H. R. Ahmad
    • 1
  • H. H. Loeschcke
    • 1
  • H. H. Woidtke
    • 1
  1. 1.Institut für PhysiologieRuhr-Universität BochumBochum 1Germany

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