Cell side-specific sensitivities of intracellular Ca2+ stores for inositol 1,4,5-trisphosphate, cyclic ADP-ribose, and nicotinic acid adenine dinucleotide phosphate in permeabilized pancreatic acinar cells from mouse.
In pancreatic acinar cells hormonal stimulation leads to a cytosolic Ca(2+) wave that starts in the apical cell pole and subsequently propagates toward the basal cell side. We used permeabilized pancreatic acinar cells from mouse and the mag-fura-2 technique, which allows direct monitoring of changes in [Ca(2+)] of intracellular stores. We show here that Ca(2+) can be released from stores in all cellular regions by inositol 1,4,5-trisphosphate. Stores at the apical cell pole showed a higher affinity to inositol 1,4,5-trisphosphate (EC(50) = 89 nm) than those at the basolateral side (EC(50) = 256 nm). In contrast, cADP-ribose, a modifier of Ca(2+)-induced Ca(2+) release, and nicotinic acid adenine dinucleotide phosphate (NAADP) were able to release Ca(2+) exclusively from intracellular stores located at the basolateral cell side. Our data agree with observations that upon stimulation Ca(2+) is released initially at the apical cell side and that this is caused by high affinity inositol 1,4,5-trisphosphate receptors. Moreover, our findings allow the conclusion that in Ca(2+) wave propagation from the apical to the basolateral cell side observed in pancreatic acinar cells Ca(2+)-induced Ca(2+) release, modulated by cADP-ribose and/or NAADP, might be involved.
Krause
Elmar
E
Physiologisches Institut, Universität des Saarlandes, Gebäude 58, Homburg Saar D-66421, Germany.
Gobel
Alexandra
A
Schulz
Irene
I
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D036563:Cyclic ADP-Ribose; D003593:Cytoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes / Q000494:pharmacology; D016257:Fura-2 / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000737:chemistry*; D051379:Mice; D018613:Microscopy, Confocal; D008954:Models, Biological; D009249:NADP / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000378:metabolism; D010179:Pancreas / Q000166:cytology*; D011485:Protein Binding
D005456:Fluorescent Dyes; D036563:Cyclic ADP-Ribose; D000246:Adenosine Diphosphate Ribose; D009249:NADP; C024376:NAADP; D015544:Inositol 1,4,5-Trisphosphate; D006493:Heparin; D002118:Calcium; D016257:Fura-2