Dynamics of intracellular oxygen in PC12 Cells upon stimulation of neurotransmission

J Biol Chem. 2008 Feb 29;283(9):5650-61. doi: 10.1074/jbc.M706439200. Epub 2007 Dec 17.


Neurotransmission, synaptic plasticity, and maintenance of membrane excitability require high mitochondrial activity in neurosecretory cells. Using a fluorescence-based intracellular O2 sensing technique, we investigated the respiration of differentiated PC12 cells upon depolarization with 100 mm K+. Single cell confocal analysis identified a significant depolarization of the plasma membrane potential and a relatively minor depolarization of the mitochondrial membrane potential following K+ exposure. We observed a two-phase respiratory response: a first intense spike lasting approximately 10 min, during which average intracellular O2 was reduced from 85-90% of air saturation to 55-65%, followed by a second wave of smaller amplitude and longer duration. The fast rise in O2 consumption coincided with a transient increase in cellular ATP by approximately 60%, which was provided largely by oxidative phosphorylation and by glycolysis. The increase of respiration was orchestrated mainly by Ca2+ release from the endoplasmic reticulum, whereas the influx of extracellular Ca2+ contributed approximately 20%. Depletion of Ca2+ stores by ryanodine, thapsigargin, and 4-chloro-m-cresol reduced the amplitude of respiratory spike by 45, 63, and 71%, respectively, whereas chelation of intracellular Ca2+ abolished the response. Uncoupling of the mitochondria with the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone amplified the responses to K+; elevated respiration induced a profound deoxygenation without increasing the cellular ATP levels reduced by carbonyl cyanide p-trifluoromethoxyphenylhydrazone. Cleavage of synaptobrevin 2 by tetanus toxin, known to reduce neurotransmission, did not affect the respiratory response to K+, whereas the general excitability of d PC12 cells increased.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Biosensing Techniques
  • Calcium / metabolism
  • Glycolysis / drug effects
  • Glycolysis / physiology
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology*
  • Microscopy, Fluorescence
  • Mitochondria / metabolism*
  • Neuronal Plasticity / drug effects
  • Neuronal Plasticity / physiology
  • Neurotoxins / pharmacology
  • Oxidative Phosphorylation / drug effects
  • Oxygen / metabolism*
  • Oxygen Consumption / drug effects
  • Oxygen Consumption / physiology*
  • PC12 Cells
  • Potassium / metabolism
  • Potassium / pharmacology
  • Rats
  • Synapses / metabolism*
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology*
  • Tetanus Toxin / pharmacology
  • Time Factors
  • Vesicle-Associated Membrane Protein 2 / metabolism


  • Neurotoxins
  • Tetanus Toxin
  • Vamp2 protein, rat
  • Vesicle-Associated Membrane Protein 2
  • Adenosine Triphosphate
  • Potassium
  • Oxygen
  • Calcium