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Impact of mitochondrial Ca2+ cycling on pattern formation and stability

Authors

  • M. Falcke
  • J.L. Hudson
  • P. Camacho
  • J.D. Lechleiter

Journal

  • Biophysical Journal

Citation

  • Biophys J 77 (1): 37-44

Abstract

  • Energization of mitochondria significantly alters the pattern of Ca2+ wave activity mediated by activation of the inositol (1,4,5) trisphosphate (IP3) receptor (IP3R) in Xenopus oocytes. The number of pulsatile foci is reduced and spiral Ca2+ waves are no longer observed. Rather, target patterns of Ca2+ release predominate, and when fragmented, fail to form spirals. Ca2+ wave velocity, amplitude, decay time, and periodicity are also increased. We have simulated these experimental findings by supplementing an existing mathematical model with a differential equation for mitochondrial Ca2+ uptake and release. Our calculations show that mitochondrial Ca2+ efflux plays a critical role in pattern formation by prolonging the recovery time of IP3Rs from a refractory state. We also show that under conditions of high energization of mitochondria, the Ca2+ dynamics can become bistable with a second stable stationary state of high resting Ca2+ concentration.


DOI

doi:10.1016/S0006-3495(99)76870-0