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Cytoplasmic pH influences cytoplasmic calcium in MC3T3-E1 osteoblast cellsWe found that the cytoplasmic concentration of calcium (Cai) of MC3T3-E1 osteoblasts was influenced by the type of pH buffer we used in the perfusing medium, suggesting that intracellular pH (pHi) might influence Cai. To study this effect, the Cai and pHi were monitored as we applied various experimental conditions known to change pHi. Exposure to NH4Cl caused a transient increase in both pHi and Cai without a change in extracellular pH (pHo). Decreasing pHo and pHi by lowering the bicarbonate concentration of the medium decreased Cai, and increasing pHi by the removal of 5% CO2 increased Cai. Clamping pHi to known values with 10 microM nigericin, a potassium proton ionophore, also influenced Cai: acid pHi lowered Cai, whereas alkaline pHi increased it. The rise in Cai appears to be very sensitive to the extracellular concentration of calcium, suggesting the existence of a pH-sensitive calcium influx mechanism. We conclude that physiologic changes in pH could modulate Cai by controlling the influx of calcium ions and could change the time course of the Cai transient associated with hormonal activation.
Document ID
20040199701
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Lin, H. S.
(University of the Pacific San Francisco, California)
Hughes-Fulford, M.
Kumegawa, M.
Pitts, A. C.
Snowdowne, K. W.
Date Acquired
August 22, 2013
Publication Date
June 1, 1993
Publication Information
Publication: Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research
Volume: 8
Issue: 6
ISSN: 0884-0431
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Program Space Biology
NASA Discipline Developmental Biology
Non-NASA Center
NASA Discipline Number 40-20

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