Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 80 (5), 2133-9

Mouse Mast Cell Secretory Granules Can Function as Intracellular Ionic Oscillators

Affiliations

Mouse Mast Cell Secretory Granules Can Function as Intracellular Ionic Oscillators

I Quesada et al. Biophys J.

Abstract

Fluorescent Ca2+ probes and digital photo-sectioning techniques were used to directly study the dynamics of Ca2+ in isolated mast cell granules of normal (CB/J) and beige (Bg(j)/Bg(j)) mice. The resting intraluminal free Ca2+ concentration ([Ca2+]L) is 25 +/- 4.2 microM (mean +/- SD, n = 68). Exposure to 3 microM inositol 1,4,5-trisphosphate (InsP3) induced periodic oscillations of luminal Ca2+ ([Ca2+]L) of approximately 10 microM amplitude and a period around 8-10 s. The [Ca2+]L oscillations were accompanied by a corresponding oscillatory release of [Ca2+]L to the extraluminal space. Control experiments using ruthenium red (2 microM) and thapsigargin (100 nM) ruled out artifacts derived from the eventual presence of mitochondria or endoplasmic reticulum in the isolated granule preparation. Oscillations of [Ca2+]L and Ca2+ release result from a Ca2+/K+ exchange process whereby bound Ca is displaced from the heparin polyanionic matrix by inflow of K+ into the granular lumen via an apamin-sensitive Ca2+-sensitive K+ channel (ASK(Ca)), whereas Ca2+ release takes place via an InsP3-receptor-Ca2+ (InsP3-R) channel. These results are consistent with previous observations of [Ca2+]L oscillations and release in/from the endoplasmic reticulum and mucin granules, and suggest that a highly conserved common mechanism might be responsible for [Ca2+]L oscillations and quantal periodic Ca2+ release in/from intracellular Ca2+ storage compartments.

Similar articles

See all similar articles

Cited by 13 articles

See all "Cited by" articles

References

    1. Cell Calcium. 1996 Dec;20(6):515-24 - PubMed
    1. Pflugers Arch. 1996 Nov-Dec;433(1-2):200-8 - PubMed
    1. J Biol Chem. 1997 Apr 4;272(14):9093-8 - PubMed
    1. Cell Calcium. 1997 Jul;22(1):1-4 - PubMed
    1. Biophys J. 1997 Sep;73(3):1169-83 - PubMed
Feedback