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Asymmetrical, agonist-induced fluctuations in local extracellular [Ca2+] in intact polarized epithelia.
- Source :
-
EMBO Journal . 11/15/2001, Vol. 20 Issue 22, p6316-6326. 11p. - Publication Year :
- 2001
-
Abstract
- We recently proposed that extracellular Ca2+ ions participate in a novel form of intercellular communication involving the extracellular Ca2+-sensing receptor (CaR). Here, using Ca2+-selective microelectrodes, we directly measured the profile of agonist-induced [Ca2+]ext changes in restricted domains near the basolateral or luminal membranes of polarized gastric acid-secreting cells. The Ca2+-mobilizing agonist carbachol elicited a transient, La3+-sensitive decrease in basolateral [Ca2+] (average ≈250 μM, but as large as 530 μM). Conversely, carbachol evoked an HgCl2- sensitive increase in [Ca2+] (average ≈400 μM, but as large as 520 μM) in the lumen of single gastric glands. Both responses were significantly reduced by pretreatment with sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) pump inhibitors or with the intracellular Ca2+ chelator BAPTA-AM. Immunofluorescence experiments demonstrated an asymmetric localization of plasma membrane Ca2+ ATPase (PMCA), which appeared to be partially co-localized with CaR and the gastric H+/K+-ATPase in the apical membrane of the acid-secreting cells. Our data indicate that agonist stimulation results in local fluctuations in [Ca2+]ext that would be sufficient to modulate the activity of the CaR on neighboring cells. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02614189
- Volume :
- 20
- Issue :
- 22
- Database :
- Academic Search Index
- Journal :
- EMBO Journal
- Publication Type :
- Academic Journal
- Accession number :
- 12955478
- Full Text :
- https://doi.org/10.1093/emboj/20.22.6316