Inositol trisphosphate-independent agonist-stimulated calcium influx in rat pancreatic acinar cells

R. K. Dawra, A. K. Saluja, M. Runzi, M. L. Steer

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Abstract

CCK-JMV-180 is a cholecystokinin analog that stimulates digestive enzyme secretion from pancreatic acinar cells but does not cause either generation of inositol 1,4,5-trisphosphate or depletion of the inositol 1,4,5- trisphosphate-sensitive intracellular Ca2+ storage pool. We report that CCK-JMV-180 can accelerate Ca2+ influx into fura-2-loaded dispersed rat pancreatic acini and single acinar cells. Furthermore, CCK-JMV-180 accelerates Ca2+ influx into cells microinjected with the inositol 1,4,5- trisphosphate receptor antagonist heparin and into acini loaded with the Ca2+-chelating agent BAPTA (1,2-bis(2-aminophenoxy)ethane-N,N,N',N'- tetraacetic acid). These results indicate that agonist-stimulated Ca2+ influx can occur (a) without depletion of the inositol 1,4,5-trisphosphate- sensitive intracellular Ca2+ storage pool, (b) without a rise in cytoplasmic free Ca2+ concentrations, and (c) after blockade of inositol 1,4,5-trisphosphate receptors. They suggest that depletion of an inositol 1,4,5-trisphosphate-independent intracellular Ca2+ storage pool and/or generation of a non-inositol 1,4,5-trisphosphate second messenger by CCK- JMV-180 may be a sufficient signal for acceleration of Ca2+ influx into rat pancreatic acinar cells.

Original languageEnglish (US)
Pages (from-to)20237-20242
Number of pages6
JournalJournal of Biological Chemistry
Volume268
Issue number27
StatePublished - Jan 1 1993

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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