Neurochemical Research

, Volume 13, Issue 11, pp 1043–1048 | Cite as

Pyruvate dehydrogenase complex is inhibited in calcium-loaded cerebrocortical mitochondria

  • James C. K. Lai
  • James C. DiLorenzo
  • Kwan-Fu Rex Sheu
Original Articles


An impairment of mitochondrial functions as a result of Ca-loading may be one of the significant events that lead to neuronal death after an ischemic insult. To assess the metabolic consequences of excess Ca on brain mitochondria, pyruvate oxidation was studied in isolated cerebrocortical mitochondria loaded with Ca in vitro. The flux of pyruvate dehydrogenase complex (PDHC) ([1-14C]pyruvate decarboxylation) was inhibited as the mitochondria accumulated excess Ca under the conditions tested: the inhibition in state 3 (i.e., in the presence of added ADP) was greater than in state 4 (i.e., in the absence of added adenine nucleotides). In state 4, the inhibition of the PDHC flux was accompanied by a similar reduction of the in situ activity of PDHC, indicating a change in PDHC phosphorylation. In state 3, the inhibition of the PDHC flux was greater than the corresponding decrease of the in situ PDHC activity. Thus, mechanisms other than the phosphorylation of PDHC might also contribute to the inhibition of pyruvate oxidation. Measurement of PDHC enzymatic activity in vitro indicated that PDHC, similar to α-ketoglutarate dehydrogenase complex, was inhibited by millimolar levels of Ca. This observation suggests that PDHC may also be inhibited non-covalently in Ca-loaded mitochondria in a manner similar to that of α-ketoglutarate dehydrogenase complex.

Key Words

Brain Mitochondria calcium ischemia protein phosphorylation pyruvate dehydrogenase 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Siesjö, B. K. 1981. Cell damage in the brain: A speculative synthesis. J. Cerb. Blood Flow Metab. 1:155–185.Google Scholar
  2. 2.
    Farber, J. L., Chien, K. R., and Mittnacht Jr. S. 1981. The pathogenesis of irreversible cell injury in ischemia. Am. J. Pathol. 102:271–281.PubMedGoogle Scholar
  3. 3.
    Raichle, M. E. 1983. The pathophysiology of brain ischemia. Ann. Neurol. 13:2–10.PubMedGoogle Scholar
  4. 4.
    Cheung, J. Y., Bonventre, J. V., Malis, C. D., and Leaf, A. 1986. Calcium and ischemic injury. N. Eng. J. Med. 314:1670–1676.Google Scholar
  5. 5.
    Dienel, G. A. 1984. Regional accumulation of calcium in postischemic rat brain. J. Neurochem. 43:913–925.PubMedGoogle Scholar
  6. 6.
    Simon, R. P., Griffiths, T., Evans, M. C., Swan, J. H., and Meldrum, B. S. 1984. Calcium overload in selectively vulnerable neurons of the hippocampus during and after ischemia: A electron-microscopy study in the rat. J. Cereb. Blood Flow Metab. 4:350–361.PubMedGoogle Scholar
  7. 7.
    Deshpande, J. K., Siesjö, B. K., and Wieloch, T. 1987. Calcium accumulation and neuronal damage in the rat hippocampus following cerebral ischemia. J. Cereb. Blood Flow Metab. 7:89–95.PubMedGoogle Scholar
  8. 8.
    Griffiths, T., Evans, M. C., and Meldrum, B. S. 1982. Intracellular sites of early calcium accumulation in the rat hippocampus during status epilepticus. Neurosci. Lett. 30:329–334.PubMedGoogle Scholar
  9. 9.
    Happel, R. D., Smith, K. P., Banik, N. L., Powers, J. M., Hogan, E. L., and Balentine, J. D. 1981. Ca2+-accumulation in experimental spinal cord trauma. Brain Res 211:476–479.PubMedGoogle Scholar
  10. 10.
    Garcia, H., Mitchem, H. L., Briggs, L., Morawetz, R., Hudetz, A. G., Hazelrig, J. B., Halsey Jr. J. H., and Conger, K. A. 1983. Transient focal ischemia in subhuman primates. Neuronal injury as a function of local cerebral blood flow. J. Neuropath. Exp. Neurol. 42:44–60.PubMedGoogle Scholar
  11. 11.
    Åkerman, K. O., and Nicholls, D. G. 1983. Physiological and bioenergetic aspects of mitochondrial calcium transport. Rev. Physiol. Biochem Pharmacol. 35:149–201.Google Scholar
  12. 12.
    Carafoli, E. 1987. Intracellular calcium homeostasis. Ann. Rev. Biochem. 56:395–433.Google Scholar
  13. 13.
    Blaustein, M. P., Ratzlaff, R. W., Kendrick, N. C., and Schweitzer, E. S. 1978. Calcium buffering in presynaptic nerve terminals. I. Evidence for involvement of a nonmitochondrial ATP-dependent sequestration mechanism. J. Gen. Physiol. 72:15–41.PubMedGoogle Scholar
  14. 14.
    Nicholls, D. G., and Scott, I. D. 1980. The regulation of brain mitochondrial calcium-ion transport. The role of ATP in the discrimation between kinetic and membrane-potential-dependent calcium-ion efflux mechanisms. Biochem. J. 186:833–839.PubMedGoogle Scholar
  15. 15.
    Greenwalt, J. W., Rossi, C. S., and Lehninger, A. L. 1964. Effect of active accumulation of calcium and phosphate ions on the structure of rat liver mitochondria. J. Cell Biol. 23:21–38.PubMedGoogle Scholar
  16. 16.
    Lehninger, A. L. 1970. Mitochondria and calcium ion transport. Biochem. J. 119:129–138.PubMedGoogle Scholar
  17. 17.
    Hillered, L., Siesjö, B. K., and Arfors, K-E. 1984. Mitochondrial response to transient forebrain ischemia and recirculation in the rat. J. Cereb. Blood Flow Metab 4:438–446.PubMedGoogle Scholar
  18. 18.
    Sims, N. R., Finegan, J. M., and Blass, J. P. 1986. Effect of postdecapitative ischemia, on mitochondrial respiration in brain tissue homogenates. J. Neurochem. 47:506–511.PubMedGoogle Scholar
  19. 19.
    Wieloch, T., and Koide, T. 1987. Pyruvate dehydrogenase is inhibited in the recirculation period following transient cerebral ischemia. J. Cereb. Blood Flow Metab. 7 (Suppl. 1): S75.Google Scholar
  20. 20.
    Welsh, F. A., Katayama, Y., and McKee, A. E. 1988. Effect of dichloroacetate on metabolite recovery following ischemia. Trans. Am. Soc. Neurochem. 19:149.Google Scholar
  21. 21.
    Randle, P. J. 1981. Phosphorylation-dephosphorylation cycles and the regulation of fuel selection in mammals. Pages 107–129,in Eastabrook, R. W., and Srere, P. (eds.), Current Topics of Cellular Regulations, Vol. 18, Academic Press, New York.Google Scholar
  22. 22.
    Wieland, O. H. 1983. The mammalian pyruvate dehydrogenase complex: Structures and regulation. Rev. Physiol. Biochem. Pharmacol. 96:127–170.Google Scholar
  23. 23.
    Marshall, S. E., McCormack, J. G., and Denton, R. M. 1984. Role of Ca2+ ions in the regulation of intramitochondrial metabolism in rat epididymal adipose tissue. Evidence against a role for Ca2+ in the activation of pyruvate dehydrogenase by insulin. Biochem. J. 218:249–260.PubMedGoogle Scholar
  24. 24.
    McCormack, J. G. 1985. Characterization of the effects of Ca2+ on the intramitochondrial Ca2+-sensitive enzymes from rat liver and within intact rat liver mitochondria. Biochem. J. 231:581–595.PubMedGoogle Scholar
  25. 25.
    Bernard, P. A., and Cockrell, R. S. 1984. Calcium transport by rat brain mitochondria and oxidation of 2-oxoglutarate. Biochim. Biophys. Acta 766:549–553.PubMedGoogle Scholar
  26. 26.
    Lai, J. C. K., and Cooper, A. J. L. 1986. Brain α-ketoglutarate dehydrogenase complex: kinetic properties, regional distribution, and effects of inhibitors. J. Neurochem. 47:1376–1386.PubMedGoogle Scholar
  27. 27.
    Sheu, K.-F. R., Lai, J. C. K., DiLorenzo, J. C., and Blass, J. P. 1985. Calcium inactivates pyruvate dehydrogenase complex in brain mitochondria. Trans. Am. Soc. Neurochem. 16:193.Google Scholar
  28. 28.
    Lai, J. C. K., and Clark, J. B. 1979. Preparation of synaptic and nonsynaptic mitochondria from mammalian brain. Methods Enzymol. 55(F):51–60.PubMedGoogle Scholar
  29. 29.
    Lai, J. C. K., and Sheu, K.-F. R. 1985. Relationship between activation state of pyruvate dehydrogenase complex and rate of pyruvate oxidation in isolated cerebro-cortical mitochondria: The effects of potassium ions and adenine nucleotides. J. Neurochem. 45:1861–1868.PubMedGoogle Scholar
  30. 30.
    Sheu, K.-F. R. and Kim, Y. T. 1984. Studies on the bovine brain pyruvate dehydrogenase complex using the antibodies against kidney enzyme complex. J. Neurochem. 43:1352–1358.PubMedGoogle Scholar
  31. 31.
    Machicao, F., and Wieland, O. H. 1980. Subunit structure of dihydrolipoamide acetyltransferase component of pyruvate dehydrogenase complex from bovine kidney. Hoppe-Seyler's Z. Physiol. Chem. 361:1093–1106.PubMedGoogle Scholar
  32. 32.
    Lai, J. C. K., and Sheu, K.-F. R. 1987. The effect of 2-oxoglutarate or 3-hydroxybutyrate on pyruvate dehydrogenase complex in isolated cerebrocortical mitochondria. Neurochem. Res. 12:715–722.PubMedGoogle Scholar
  33. 33.
    Sheu, K.-F. R., Lai, J. C. K., and Blass, J. P. 1984. Properties and regional distribution of pyruvate dehydrogenase kinase in rat brain. J. Neurochem. 42:230–236.PubMedGoogle Scholar
  34. 34.
    Linn, T. C., Pelley, J. W., Pettit, F. H., Hucho, F., Randall, D. D., and Reed, L. J. 1972. α-Keto acid dehydrogenase complexes: XV. Purification and properties of the component enzymes of the pyruvate dehydrogenase complexes from bovine kidney and heart. Arch. Biochem. Biophys. 148:327–342.PubMedGoogle Scholar
  35. 35.
    Lowry, O. H., Rosenbrough, N. J., Farr, A. L., and Randall, R. J. 1951. Protein measurement with the Folin phenol reagent. J. Biol. Chem. 193:265–275.PubMedGoogle Scholar
  36. 36.
    Guroff, G. 1964. A neutral, calcium-activated proteinase from the soluble fraction of rat brain. J. Biol. Chem. 239:149–155.PubMedGoogle Scholar
  37. 37.
    Ikeda, M., Yoshida, S., Busto, R., Santiso, M., and Ginsberg, M. D. 1986. Polyphosphoinositides as a probable source of brain free fatty acids accumulated at the onset of ischemia. J. Neurochem. 47:123–132.PubMedGoogle Scholar

Copyright information

© Plenum Publishing Corporation 1988

Authors and Affiliations

  • James C. K. Lai
    • 1
  • James C. DiLorenzo
    • 1
  • Kwan-Fu Rex Sheu
    • 1
  1. 1.Department of Biochemistry and NeurologyCornell University Medical College. Burke Rehabilitation CenterWhite Plains

Personalised recommendations