Low concentrations of protein kinase c-activating agonists suppress cholecystokinin-ope-evoked ca2 mobilization in rat pancreatic acini

Herbert Y. Gaisano, Laurence J. Miller

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

The phenethyl ester analogues of cholecystokinin, OPE and JMV-180, are fully efficacious rat pancreatic secretagoguges which, unlike cholecystokinin (CCK), do not elicit supramaximal inhibition of secretion, and stimulate a sustained rise of cytosolic calcium ([Ca2+]i) above basal levels. We have recently shown that low-level protein kinase C (PKC) activation by preincubation of acini with 1 nM 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or minimally secreting concentrations of PKC-activating receptor agonists (1 pM CCK-8, 0.1 μM carbachol or 10 μM bombesin) cause supramaximal inhibition of OPE-stimulated enzyme secretion. We now show that treatment of acini under these conditions also suppresses the sustained rise of [Ca2+]istimulated by OPE to basal levels in these cells, without changing the initial OPE-stimulated [Ca2+]ipeak. The resultant pattern of calcium signalling is similar to that evoked by supramaximal concentrations of native CCK. This suggests that even low concentrations of PKC-activating agonists have the potential to induce inhibitory effects on Ca2+ mobilization and that this kinase is important in generating the supramaximal inhibition observed in response to CCK.

Original languageEnglish (US)
Pages (from-to)450-453
Number of pages4
JournalPancreas
Volume9
Issue number4
DOIs
StatePublished - Jul 1994

Keywords

  • Camobilization
  • Cholecystokinin
  • Heterologous agonists
  • OPE
  • Pancreatic acinar cell
  • Protein kinase C

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism
  • Hepatology
  • Endocrinology

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