Purinergic receptors stimulate Na+/Ca2+ exchange in pancreatic duct cells: possible role of proteins handling and transporting Ca2+.
Most purinergic receptors activate intracellular Ca(2+) signalling, and in epithelia they stimulate transport of major ions. Aim of the present study on pancreatic ducts was to find whether P2 receptors also regulate cellular Ca(2+) transport, such as that via the Na(+)/Ca(2+) exchanger (NCX). Since NCX can also be connected with epithelial Ca(2+) transport, we also investigated expression of some Ca(2+)-handling/transporting proteins. Expression analysis revealed that pancreatic ducts of rat and human duct cell line CFPAC-1 (also PANC-1 and Capan-1) express the Na(+)/Ca(2+) exchanger (splice variants NCX1.3 and 1.7), as well as the Ca(2+)-sensing receptor and the Ca(2+)-binding protein calbindin-D 9k. These proteins localize to the luminal and lateral membranes of pancreatic duct epithelia. Ca(2+) imaging experiments showed that activation of purinergic P2Y and P2X receptors stimulated NCX in human and rat duct cells. Application of ATP to CFPAC-1 monolayers also stimulated Ca(2+) transport from the luminal to the basolateral side. Taken together, these results show that pancreatic ducts express a number of Ca(2+)-handling/transporting proteins and we propose that these together with purinergic receptors play a role in regulation of duct lumen Ca(2+) content.
Hansen
Mette R
MR
Department of Biology, August Krogh Building, University of Copenhagen, Denmark.
Krabbe
Simon
S
Ankorina-Stark
Ieva
I
Novak
Ivana
I
D000818:Animals; D064026:Calbindins; D002118:Calcium / Q000378:metabolism*; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000378:metabolism*; D006801:Humans; D017136:Ion Transport; D010183:Pancreatic Ducts / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D044169:Receptors, Calcium-Sensing / Q000378:metabolism; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D015398:Signal Transduction; D019831:Sodium-Calcium Exchanger / Q000378:metabolism*
D064026:Calbindins; D044169:Receptors, Calcium-Sensing; D018048:Receptors, Purinergic P2; D064030:S100 Calcium Binding Protein G; D019831:Sodium-Calcium Exchanger; D002118:Calcium