QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online 23 August 2005
doi: 10.1242/jcs.02533

This Article Figures Only Full Text Full Text (PDF) Supplementary Material All Versions of this Article: jcs.02533v1 118/18/4131    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Larina, O. Articles by Thorn, P. Search for Related Content PubMed PubMed Citation Articles by Larina, O. Articles by Thorn, P.

Ca²⁺ dynamics in salivary acinar cells: distinct morphology of the acinar lumen underlies near-synchronous global Ca²⁺ responses

Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK

^* Author for correspondence (e-mail: pt207{at}cam.ac.uk)

Accepted 9 June 2005

In salivary acinar cells, the pattern of the Ca²⁺ signals that regulates fluid and enzyme secretion has yet to be resolved, as there are conflicting reports in the literature. We have used a two-photon technique to directly visualize the acinar cell lumen in living fragments of exocrine tissue and simultaneously recorded agonist-induced changes in intracellular Ca²⁺. We show near-synchronous global Ca²⁺ responses in submandibular acinar cells, distinct from the typical apical to basal Ca²⁺ wave usually seen in rodent pancreatic acinar cells. In an effort to explain the basis of these near-synchronous global Ca²⁺ responses we used immunocytochemical experiments to localize luminal proteins and inositol trisphosphate receptors (InsP₃Rs) in tissue fragments. Zona occludens 1 (ZO-1), a tight junction protein, shows that individual submandibular acinar cells are often nearly completely encircled by a narrow luminal structure. By contrast, in pancreatic fragments, ZO-1 staining shows short luminal branches terminating abruptly at the apical pole of single acinar cells. Co-immunostaining of InsP₃Rs type 2 and type 3 showed them in the same region as ZO-1 in both exocrine tissues. Functional experiments showed that the near-synchronous global Ca²⁺ responses were still observed in the absence of extracellular Ca²⁺ and also in the presence of ryanodine. We conclude that the elaborate luminal region of submandibular cells leads to a hitherto unrecognized extensive distribution of InsP₃Rs in a band around the cell and that this underlies the near-synchronous global Ca²⁺ response to agonists. We suggest that this may be a structural adaptation in submandibular cells to support the copious amounts of fluid secreted.

Key words: Acinar, Salivary gland, Calcium, Lumen

This article has been cited by other articles:

				J. H. Won, W. J. Cottrell, T. H. Foster, and D. I. Yule Ca2+ release dynamics in parotid and pancreatic exocrine acinar cells evoked by spatially limited flash photolysis Am J Physiol Gastrointest Liver Physiol, December 1, 2007; 293(6): G1166 - G1177. [Abstract] [Full Text] [PDF]