A single-pool model for intracellular calcium oscillations and waves in the Xenopus laevis oocyte

Biophys J. 1993 Oct;65(4):1727-39. doi: 10.1016/S0006-3495(93)81191-3.


We construct a minimal model of cytosolic free Ca2+ oscillations based on Ca2+ release via the inositol 1,4,5-trisphosphate (IP3) receptor/Ca2+ channel (IP3R) of a single intracellular Ca2+ pool. The model relies on experimental evidence that the cytosolic free calcium concentration ([Ca2+]c) modulates the IP3R in a biphasic manner, with Ca2+ release inhibited by low and high [Ca2+]c and facilitated by intermediate [Ca2+]c, and that channel inactivation occurs on a slower time scale than activation. The model produces [Ca2+]c oscillations at constant [IP3] and reproduces a number of crucial experiments. The two-dimensional spatial model with IP3 dynamics, cytosolic diffusion of IP3 (Dp = 300 microns 2 s-1), and cytosolic diffusion of Ca2+ (Dc = 20 microns 2 s-1) produces circular, planar, and spiral waves of Ca2+ with speeds of 7-15 microns.s-1, which annihilate upon collision. Increasing extracellular [Ca2+] influx increases wave speed and baseline [Ca2+]c. A [Ca2+]c-dependent Ca2+ diffusion coefficient does not alter the qualitative behavior of the model. An important model prediction is that channel inactivation must occur on a slower time scale than activation in order for waves to propagate. The model serves to capture the essential macroscopic mechanisms that are involved in the production of intracellular Ca2+ oscillations and traveling waves in the Xenopus laevis oocyte.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biological Clocks
  • Biophysical Phenomena
  • Biophysics
  • Calcium / metabolism*
  • Calcium Channels / metabolism
  • Cytosol / metabolism
  • Diffusion
  • Female
  • Inositol 1,4,5-Trisphosphate / metabolism
  • Inositol 1,4,5-Trisphosphate Receptors
  • Kinetics
  • Models, Biological*
  • Oocytes / metabolism*
  • Photolysis
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Xenopus laevis


  • Calcium Channels
  • Inositol 1,4,5-Trisphosphate Receptors
  • Receptors, Cytoplasmic and Nuclear
  • Inositol 1,4,5-Trisphosphate
  • Calcium