Ca2+ wave dispersion and spiral wave entrainment in Xenopus laevis oocytes overexpressing Ca2+ ATPases

James D. Lechleiter, Linu M. John, Patricia Camacho

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


Complex, spatiotemporal patterns of intracellular Ca2+ release in Xenopus oocytes can be accounted for by the operation of two fundamental processes: Ca2+ release from the endoplasmic reticulum (ER) via the inositol 1,4,5-trisphosphate receptor (IP3R) with its inherent dependency on cytosolic Ca2+, and Ca2+ uptake via Ca2+ ATPases. Overexpression of sarco-endoplasmic reticulum Ca2+ ATPases (SERCAs) in Xenopus oocytes, increases IP3-induced Ca2+ wave frequency and amplitude [ 1-3]. This effect can be attributed to an increased removal of cytoplasmic Ca2+ and more efficient refilling of Ca2+ stores. By overexpressing SERCA isoforms, we report here that Ca2+ waves exhibit dispersion [4-6]. At wavelengths greater than 60 μm, wave velocity is constant. However, wave velocity and amplitude progressively decreases at smaller wavelengths. Below λ -20 μm, Ca2+ waves disperse and fail to propagate. In oocytes exhibiting both spiral and target patterns of Ca2+ release, spiral waves had higher frequencies and showed entrainment of the surrounding regions. These properties are characteristic of a classical excitable medium [4-6].

Original languageEnglish (US)
Pages (from-to)123-129
Number of pages7
JournalBiophysical Chemistry
Issue number1-2
StatePublished - May 5 1998


  • Ca oscillations
  • Excitable media
  • Inositol
  • Oocytes

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Organic Chemistry


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