Effects of AIF4- and ATP on intracellular calcium dynamics of crypt epithelial cells in mouse small intestine.
Previous digital imaging analysis of intracellular calcium ion ([Ca2+]i) dynamics in the crypt of the small intestine showed little response by most columnar cells to cholinergic and adrenergic agonists. The objective of the present study was to demonstrate whether G-protein activators and other transmitters elicit [Ca2+]i changes in crypt cells. We used digital imaging to analyze spatiotemporal dynamics of [Ca2+]i in Fura-2/AM-loaded isolated crypts of mouse duodenum and ileum. A1F4- increased [Ca2+]i in crypt columnar cells. In many cases, we observed [Ca2+]i oscillations, which were synchronized throughout the entire crypt. The oscillations were blocked by octanol. ATP, but not adenosine, caused a [Ca2+]i increase in middle crypt-regions of the duodenum and upper regions of the ileum, and the [Ca2+]i wave propagated towards the crypt bottom. The ATP-induced [Ca2+]i increase was prevented by pretreatment with thapsigargin or suramin, but not by La3+ or an extracellular Ca(2+)-free environment. Neither dopamine, 5-hydroxytryptamine (5-HT), histamine, vasoactive intestinal peptide, substance P. cholera toxin, nor guanylin had significant effects. The [Ca2+]i dynamics of Paneth cells were independent of the AlF4(-)-induced synchronous oscillations of columnar cells and of the ATP-induced [Ca2+]i wave. In conclusion, crypt columnar cells have [Ca2+]i-dependent intracellular signaling mechanisms that are linked with G proteins, and by which the cells communicate with each other. ATP elicited [Ca2+]i mobilization from columnar cells via P2 receptors, although some regional differences were noted between the duodenum and ileum.
Satoh
Y
Y
Department of Histology, Iwate Medical University, Morioka, Japan. yisatoh@iwate-med.ac.jp
Williams
M R
MR
Habara
Y
Y
D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology; D017607:Aluminum Compounds / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004386:Duodenum / Q000166:cytology / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism / Q000648:ultrastructure; D005459:Fluorides / Q000378:metabolism* / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D007082:Ileum / Q000166:cytology / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D010477:Perfusion; D015398:Signal Transduction
D017607:Aluminum Compounds; C050992:tetrafluoroaluminate; D000255:Adenosine Triphosphate; D019204:GTP-Binding Proteins; D005459:Fluorides; D002118:Calcium