caa a22 4500 477121063 CHVBK 20180405111637.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/BF00226780 doi (NATIONALLICENCE)springer-10.1007/BF00226780 The role of magnesium in regulating CCK-8-evoked secretory responses in the exocrine rat pancreas [Elektronische Daten] [Denham Wisdom, Gines Salido, Lisa Baldwin, Jaipaul Singh] This study investigates the effect of magnesium (Mg2+) on the secretory responses and the mobilization of calcium (Ca2+) and Mg2+ evoked by cholecystokinin-octapeptide (CCK-8) in the exocrine rat pancreas. In the isolated intact perfused pancreas CCK-8 (10−10 M) produced marked increases in juice flow and total protein output in zero and normal (1.1 mM) extracellular Mg2+ [Mg2+]o compared to a much reduced secretory response in elevated (5 mM and 10 mM) [Mg2+]o Similar effects of perturbation of [Mg2+]o on amylase secretion and 45Ca2+ uptake (influx) were obtained in isolated pancreatic segments. In pancreatic acinar cells loaded with the fluorescent bioprobe fura-2 acetomethylester (AM), CCK-8 evoked marked increases in cytosolic free Ca2+ concentration [Ca2+]i in zero and normal [Mg2+]o compared to a much reduced response in elevated [Mg2+]o Pretreatment of acinar cells with either dibutyryl cyclic AMP (DB2 cAMP) or forskolin had no effect on the CCK-8 induced changes in [Ca2+]i. In magfura-2-loaded acinar cells CCK-8 (10−8 M) stimulated an initial transient rise in intracellular free Mg2+ concentration [Mg2+]i followed by a more prolonged and sustained decrease. This response was abolished when sodium Na+ was replaced with N-methyl-D-glucamine (NMDG). Incubation of acinar cells with 10 mM Mg2+ resulted in an elevation in [Mg2+]i. Upon stimulation with CCK-8, [Mg2+]i. decreased only slightly compared with the response obtained in normal [Mg2+]o. CCK-8 caused a net efflux of Mg2+ in pancreatic segments; this effect was abolished when extracellular sodium [Na+]o was replaced with either NMDG or choline. The results indicate that Mg2+ can regulate CCK-8-evoked secretory responses in the exocrine pancreas possibly via Ca2+ mobilization. Moreover, the movement of Mg2+ in pancreatic acinar cells is dependent upon extracellular Na+. Kluwer Academic Publishers, 1996 rat pancreas nationallicence cholecystokinin-octapeptide nationallicence magnesium nationallicence calcium nationallicence secretion nationallicence cyclic AMP nationallicence Wisdom Denham Cell Communication Group, Department of Applied Biology, University of Central Lancashire, PR1 2HE, Preston, England, UK aut Salido Gines Department of Physiology, Faculty of Veterinary Sciences, University of Extramadura, 10800, Caceres, Spain aut Baldwin Lisa Cell Communication Group, Department of Applied Biology, University of Central Lancashire, PR1 2HE, Preston, England, UK aut Singh Jaipaul Cell Communication Group, Department of Applied Biology, University of Central Lancashire, PR1 2HE, Preston, England, UK aut Molecular and Cellular Biochemistry Kluwer Academic Publishers; gopher//gopher.wkap.nl 154/2(1996-09-01), 123-132 0300-8177 154:2<123 1996 154 11010 https://doi.org/10.1007/BF00226780 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00226780 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wisdom Denham Cell Communication Group, Department of Applied Biology, University of Central Lancashire, PR1 2HE, Preston, England, UK aut NATIONALLICENCE 700 1- Salido Gines Department of Physiology, Faculty of Veterinary Sciences, University of Extramadura, 10800, Caceres, Spain aut NATIONALLICENCE 700 1- Baldwin Lisa Cell Communication Group, Department of Applied Biology, University of Central Lancashire, PR1 2HE, Preston, England, UK aut NATIONALLICENCE 700 1- Singh Jaipaul Cell Communication Group, Department of Applied Biology, University of Central Lancashire, PR1 2HE, Preston, England, UK aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers; gopher//gopher.wkap.nl/ 154/2(1996-09-01), 123-132 0300-8177 154:2<123 1996 154 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer