Quick Search:

uzh logo
Browse by:
bullet
bullet
bullet
bullet

Zurich Open Repository and Archive 

Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-14323

Remy, C; Kirchhoff, P; Hafner, P; Busque, S M; Müeller, M K; Geibel, J P; Wagner, C A (2007). Stimulatory pathways of the Calcium-sensing receptor on acid secretion in freshly isolated human gastric glands. Cellular Physiology and Biochemistry, 19(1-4):33-42.

[img]PDF - Registered users only
1260Kb

Abstract

Gastric acid secretion is not only stimulated via the classical known neuronal and hormonal pathways but also by the Ca(2+)-Sensing Receptor (CaSR) located at the basolateral membrane of the acid-secretory gastric parietal cell. Stimulation of CaSR with divalent cations or the potent agonist Gd(3+) leads to activation of the H(+)/K(+)-ATPase and subsequently to gastric acid secretion. Here we investigated the intracellular mechanism(s) mediating the effects of the CaSR on H(+)/K(+)-ATPase activity in freshly isolated human gastric glands. Inhibition of heterotrimeric G-proteins (G(i) and G(o)) with pertussis toxin during stimulation of the CaSR with Gd(3+) only partly reduced the observed stimulatory effect. A similar effect was observed with the PLC inhibitor U73122. The reduction of the H(+)/K(+)-ATPase activity measured after incubation of gastric glands with BAPTA-AM, a chelator of intracellular Ca(2+), showed that intracellular Ca(2+) plays an important role in the signalling cascade. TMB-8, a ER Ca(2+)store release inhibitor, prevented the stimulation of H(+)/K(+)-ATPase activity. Also verapamil, an inhibitor of L-type Ca(2+)-channels reduced stimulation suggesting that both the release of intracellular Ca(2+) from the ER as well as Ca(2+) influx into the cell are involved in CaSR-mediated H(+)/K(+)-ATPase activation. Chelerythrine, a general inhibitor of protein kinase C, and Go 6976 which selectively inhibits Ca(2+)-dependent PKC(alpha) and PKC(betaI)-isozymes completely abolished the stimulatory effect of Gd(3+). In contrast, Ro 31-8220, a selective inhibitor of the Ca(2+)-independent PKCepsilon and PKC-delta isoforms reduced the stimulatory effect of Gd(3+) only about 60 %. On the other hand, activation of PKC with DOG led to an activation of H(+)/K(+)-ATPase activity which was only about 60 % of the effect observed with Gd(3+). Incubation of the parietal cells with PD 098059 to inhibit ERK1/2 MAP-kinases showed a significant reduction of the Gd(3+) effect. Thus, in the human gastric parietal cell the CaSR is coupled to pertussis toxin sensitive heterotrimeric G-Proteins and requires calcium to enhance the activity of the proton-pump. PLC, ERK 1/2 MAP-kinases as well as Ca(2+) dependent and Ca(2+)-independent PKC isoforms are part of the down-stream signalling cascade.

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > Center for Integrative Human Physiology
04 Faculty of Medicine > University Hospital Zurich > Clinic for Visceral and Transplantation Surgery
04 Faculty of Medicine > Institute of Physiology
07 Faculty of Science > Institute of Physiology
DDC:570 Life sciences; biology
610 Medicine & health
Language:English
Date:2007
Deposited On:18 Mar 2009 14:03
Last Modified:27 Nov 2013 18:00
Publisher:Karger
ISSN:1015-8987
Publisher DOI:10.1159/000099190
PubMed ID:17310098
Citations:Web of Science®. Times Cited: 22
Google Scholar™

Users (please log in): suggest update or correction for this item

Repository Staff Only: item control page