CCK-JMV-180, an analog of cholecystokinin, releases intracellular calcium from an inositol trisphosphate-independent pool in rat pancreatic acini

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

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

In pancreatic acinar cells cholecystokinin and its analogs, caerulein and CCK-JMV-180, stimulate an increase in intracellular free [Ca2+] by releasing Ca2+ from non-mitochondrial intracellular pools. It is generally believed that the caerulein-induced release of Ca2+ is mediated by phospholipase C-catalyzed production of 1,4,5-inositol trisphosphate (IP3). In this study we have investigated the source and mechanism of Ca2+ release induced by CCK-JMV-180 using streptolysin O-permeabilized pancreatic acinar cells. Caerulein-stimulated release of Ca2+ was completely blocked by either neomycin, an inhibitor of phospholipase C, or by heparin, an IP3 receptor antagonist. These observations are compatible with the conclusion that caerulein releases Ca2+ from an IP3-sensitive pool. In contrast to caerulein, however, CCK-JMV-180-stimulated release of Ca2+ was not blocked by either neomycin or by heparin, indicating that CCK-JMV-180 releases Ca2+ by mechanisms which do not involve the generation or action of IP3. CCK-JMV- 180 stimulated the release of Ca2+ even after the IP3-sensitive pool had been completely emptied by prior exposure to a supramaximally stimulating concentration of IP3 (40 μM). Prestimulation of permeabilized acini with 20 mM caffeine did not abolish the CCK-JMV-180-induced Ca2+ release. These results indicate that CCK-JMV-180 stimulates release of Ca2+ from a hitherto uncharacterized intracellular storage pool which is insensitive to either IP3 or caffeine.

Original languageEnglish (US)
Pages (from-to)11202-11207
Number of pages6
JournalJournal of Biological Chemistry
Volume267
Issue number16
StatePublished - Jan 1 1992
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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