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Calcium‐magnesium interactions in pancreatic acinar cells
Author(s) -
MOOREN FRANK C.,
TURI STEFAN,
GÜNZEL DOROTHEE,
SCHLUE WOLFRÜDIGER,
DOMSCHKE WOLFRAM,
SINGH JAIPAUL,
LERCH MARKUS M.
Publication year - 2001
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.00-0172com
Subject(s) - intracellular , cholecystokinin , acinar cell , chemistry , endoplasmic reticulum , biophysics , microbiology and biotechnology , calcium in biology , calcium , stimulation , medicine , endocrinology , biology , pancreas , biochemistry , receptor , organic chemistry
Although the role of calcium (Ca 2+ )in the signal transduction and pathobiology of the exo¬crine pancreas is firmly established, the role of magne¬sium (Mg 2+ ) remains unclear. We have characterized the intracellular distribution of Mg 2+ in response to hormone stimulation in isolated mouse pancreatic acinar cells and studied the role of Mg 2+ in modulating Ca 2+ signaling using microspectrofluorometry and dig¬ital imaging of Ca 2+ ‐orMg 2+ ‐sensitive fluorescent dyes as well as Mg 2+ ‐sensitive intracellular microelectrodes. Our results indicate that an increase in intracellular Mg 2+ concentrations reduced the cholecystokinin (CCK) ‐induced Ca 2+ oscillations by inhibiting the capacitive Ca 2+ influx. An intracellular Ca 2+ mobiliza¬tion, on the other hand, was paralleled by a decrease in [Mg 2+ ] i , which was reversible upon hormone with¬drawal independent of the electrochemical gradients for Mg 2+ ,Ca 2+ ,Na + , and K + , and not caused by Mg 2+ efflux from acinar cells. In an attempt to characterize possible Mg 2+ stores that would explain the reversible, hormone‐induced intracellular Mg 2+ movements, we ruled out mitochondria or ATP as potential Mg 2+ buffers and found that the CCK‐induced [Mg 2+ ] i de¬crease was initiated at the basolateral part of the acinar cells, where most of the endoplasmic reticulum (ER) is located, and progressed from there toward the apical pole of the acinar cells in an antiparallel fashion to Ca 2+ waves. These experiments represent the first characterization of intracellular Mg 2+ movements in the exocrine pancreas, provide evidence for possible Mg 2+ stores in the ER, and indicate that the spatial and temporal distribution of intracellular Mg concentra¬tions profoundly affects acinar cell Ca 2+ signaling.— Mooren, F. C., Turi, S., Günzel, D., Schlue, W.‐R., Domschke, W., Singh, J., Lerch, M. M. Calcium‐mag¬nesium interactions in pancreatic acinar cells. FASEB J. 15, 659‐672 (2001)