Pyruvate dehydrogenase dephosphorylation in rat brain synaptosomes and mitochondria: evidence for a calcium-mediated effect in response to depolarization, and variations due to ageing

Neurosci Lett. 1992 Aug 17;142(2):123-7. doi: 10.1016/0304-3940(92)90354-a.


The phosphorylation state of P42, the phosphorylated, catalytically inactive, alpha-subunit of pyruvate dehydrogenase (PDH), decreased markedly (42.4%) in response to K(+)-depolarization of synaptosomes. The dephosphorylation was rapid (5-15 s), calcium-dependent and could also be observed in isolated mitochondria exposed to a rise in extramitochondrial calcium, suggesting that P42 dephosphorylation may act as a calcium sensor in the mitochondrial matrix. The depolarization-dependent dephosphorylation rate of P42 was decreased in synaptosomes derived from 24-month-old animals with respect to 3-month-old adults. The relevance of these results in terms of PDH activation during ageing is discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / metabolism*
  • Animals
  • Brain / enzymology*
  • Calcium / physiology*
  • In Vitro Techniques
  • Male
  • Mitochondria / enzymology*
  • Nerve Tissue Proteins / metabolism
  • Neuromuscular Depolarizing Agents / pharmacology*
  • Phosphorylation
  • Pyruvate Dehydrogenase Complex / metabolism*
  • Rats
  • Rats, Wistar
  • Synaptosomes / enzymology*


  • Nerve Tissue Proteins
  • Neuromuscular Depolarizing Agents
  • Pyruvate Dehydrogenase Complex
  • Calcium