Extracellular calcium sensing receptor in human pancreatic cells

Abstract

Background and aims: The extracellular calcium sensing receptor (CaR) plays a key role in the calcium homeostatic system and is therefore widely expressed in tissues involved in calcium metabolism. However, the CaR has also been identified in other tissues where its role is less clear. We have investigated the presence of the CaR in the human pancreas. Methods: Messenger RNA for the CaR was detected by reverse transcription-polymerase chain reaction and the protein was localised by immunostaining. CaR function was assayed in Capan-1 cells by measuring intracellular calcium and [

Vectorial Bicarbonate Transport by Capan-1 Cells: a Model for Human Pancreatic Ductal Secretion

“…Transcripts were also detected for secretin, VIP/PACAP (VPAC 1 and VPAC 2 ) receptors, but not for PACAP (pituitary adenylate cyclase-activating polypeptide) receptors. Of the purinoceptors examined, positive results were obtained for P2Y 1 , P2Y 2 , P2Y 4 and P2Y 6 , and for P2X 1 , P2X 4 and P2X 5 , but not P2X 2 , P2X 6 or P2X 7 . Identities of all PCR products were confirmed by sequencing and/or restriction enzyme digest.…”

“…However, only Capan-1 cells and Panc-1 cells express functional CFTR [23,24] and, of these, only Capan-1 cells form confluent, polarized monolayers on permeable supports [9,24,25]. Although CFPAC-1 cells transfected with wild-type CFTR (CFPAC-WT) have been used successfully [10], the Capan-1 cell line has the advantage that it expresses receptors for a range of physiological stimuli, including secretin [9,25], VIP [26,27], ATP [28], angiotensin II [29] and extracellular Ca 2+ [6]. We have therefore begun a systematic study of the mechanisms and regulation of HCO 3 -transport in these cells as a candidate model for the human pancreatic duct epithelium.…”

“…-sensing receptor [6] in human pancreatic ducts. Unfortunately, it is virtually impossible to obtain sufficient human pancreatic tissue on a regular basis to permit functional studies.…”

Purinergic Receptors Stimulate Na⁺/Ca^2+ Exchange in Pancreatic Duct Cells: Possible Role of Proteins Handling and Transporting Ca^2+

“…In addition, NCX may not only be important in regulating intracellular Ca 2+ signalling, but at the organ level it could be a part of transepithelial Ca -ATPase (PMCA) and calcium sensing receptors (CaR) [8][9][10][11]. In pancreas, the normal pancreatic juice contains relatively low Ca 2+ concentrations (<0.5 mM) [12][13][14], but except for a few studies on CaR [15,16] and our studies on NCX [6,7] transport. Present study was performed on rat pancreatic ducts and on cells from human pancreatic duct lines CFPAC-1 (also PANC-1 and Capan-1), which are commonly used as models for epithelial transport of human pancreatic ducts [2].…”

The calcium-sensing receptor and insulin secretion: a role outside systemic control 15 years on

“…However, over the last decade and a half it has become apparent that the ability of cells to detect local changes in free calcium ion concentration is not restricted to tissues involved in Ca 2C homeostasis. The CaR has been detected in an ever increasing range of tissue types, including oesophageal (Justinich et al 2008) and colonic epithelia (Cheng et al 2004), the cardiovascular system (reviewed in Smajilovic & Tfelt-Hansen 2007), hypothalamic neurons (Vizard et al 2008), pancreatic ducts (Racz et al 2002) and pancreatic a-and b-cells (Rasschaert & Malaisse 1999, Squires et al 2000, Gray et al 2006.…”