Regenerative release of calcium from functionally discrete subcellular stores by inositol trisphosphate

Proc Biol Sci. 1991 Dec 23;246(1317):269-74. doi: 10.1098/rspb.1991.0154.


Fluorescence imaging was used to determine the spatial and temporal patterns of subcellular calcium (Ca2+) liberation induced in Xenopus oocytes by photorelease of inositol 1,4,5-trisphosphate (InsP3) from a caged precursor. Increasing levels of InsP3 evoked Ca2+ release that began in a graded manner but, at varying threshold levels of InsP3, localized sites then showed transient and asynchronous 'puffs' of Ca2+ release. With higher levels of InsP3, Ca2+ from adjacent sites formed a focus for initiation of a propagating Ca2+ wave. The results show that InsP3-sensitive Ca2+ stores are arranged as distinct and functionally independent units, and that Ca2+ is released in both graded and regenerative fashions.

Publication types

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

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Female
  • Inositol 1,4,5-Trisphosphate / pharmacology*
  • Kinetics
  • Oocytes / drug effects
  • Oocytes / physiology*
  • Time Factors
  • Xenopus laevis


  • Inositol 1,4,5-Trisphosphate
  • Calcium