Premium
Caffeine releases a glucose‐primed endoplasmic reticulum Ca 2+ pool in the insulin secreting cell line INS‐1
Author(s) -
Gamberucci Alessandra,
Fulceri Rosella,
Pralong William,
Bánhegyi Gabor,
Marcolongo Paola,
Watkins Sharlene L.,
Benedetti Angelo
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00220-3
Subject(s) - endoplasmic reticulum , ryanodine receptor , thapsigargin , caffeine , intracellular , extracellular , chemistry , fura 2 , endocrinology , medicine , biology , biochemistry , cytosol , enzyme
Caffeine mobilized an intracellular Ca 2+ pool in intact fura‐2‐loaded INS‐1 cells in suspension exposed to high (16 mM) [glucose], while a minor effect was observed with low (2 mM) [glucose]. Cells were kept in a medium containing diaxozide or no Ca 2+ to prevent the influx of extracellular Ca 2+ . The caffeine‐sensitive intracellular Ca 2+ pool was within the endoplasmic reticulum since it was depleted by the inhibitor of the reticular Ca 2+ pumps thapsigargin and the InsP 3 ‐dependent agonist carbachol. No effect of caffeine was observed in the parent glucose‐insensitive RINmF5 cells. In microsomes from INS‐1 but not RINmF5 cells, the type 2 ryanodine receptor was present as revealed by Western blotting. It was concluded that the endoplasmic reticulum of INS‐1 cells possesses caffeine‐sensitive type 2 ryanodine receptors Ca 2+ channels.