• search hit 6 of 6
Back to Result List

Intracellular pH regulation in unstimulated Calliphora salivary glands is Na+ dependent and requires V-ATPase activity

  • Salivary gland cells of the blowfly Calliphora vicina have a vacuolar-type H+-ATPase (V-ATPase) that lies in their apical membrane and energizes the secretion of a KCl-rich primary saliva upon stimulation with serotonin (5-hydroxytryptamine). Whether and to what extent V-ATPase contributes to intracellular pH (pH(i)) regulation in unstimulated gland cells is unknown. We used the fluorescent dye BCECF to study intracellular pH(i) regulation microfluorometrically and show that: (1) under resting conditions, the application of Na+-free physiological saline induces an intracellular alkalinization attributable to the inhibition of the activity of a Na+-dependent glutamate transporter; (2) the maintenance of resting pHi is Na+, Cl-, concanamycin A and DIDS sensitive; (3) recovery from an intracellular acid load is Na+ sensitive and requires V-ATPase activity; (4) the Na+/H+ antiporter is not involved in pHi recovery after a NH4Cl prepulse; and (5) at least one Na+-dependent transporter and the V-ATPase maintain recovery from anSalivary gland cells of the blowfly Calliphora vicina have a vacuolar-type H+-ATPase (V-ATPase) that lies in their apical membrane and energizes the secretion of a KCl-rich primary saliva upon stimulation with serotonin (5-hydroxytryptamine). Whether and to what extent V-ATPase contributes to intracellular pH (pH(i)) regulation in unstimulated gland cells is unknown. We used the fluorescent dye BCECF to study intracellular pH(i) regulation microfluorometrically and show that: (1) under resting conditions, the application of Na+-free physiological saline induces an intracellular alkalinization attributable to the inhibition of the activity of a Na+-dependent glutamate transporter; (2) the maintenance of resting pHi is Na+, Cl-, concanamycin A and DIDS sensitive; (3) recovery from an intracellular acid load is Na+ sensitive and requires V-ATPase activity; (4) the Na+/H+ antiporter is not involved in pHi recovery after a NH4Cl prepulse; and (5) at least one Na+-dependent transporter and the V-ATPase maintain recovery from an intracellular acid load. Thus, under resting conditions, the V-ATPase and at least one Na+-dependent transporter maintain normal pH(i) values of pH.7.5. We have also detected the presence of a Na+-dependent glutamate transporter, which seems to act as an acid loader. Despite this not being a common pH(i)-regulating transporter, its activity affects steady-state pH(i) in C. vicina salivary gland cells.show moreshow less

Export metadata

Additional Services

Share in Twitter Search Google Scholar Statistics
Metadaten
Author:Bettina Schewe, Wolfgang BlenauORCiDGND, Bernd Walz
DOI:https://doi.org/10.1242/jeb.063172
ISSN:0022-0949
Parent Title (English):The journal of experimental biology
Publisher:Company of Biologists Limited
Place of publication:Cambridge
Document Type:Article
Language:English
Year of first Publication:2012
Year of Completion:2012
Release Date:2017/03/26
Tag:BCECF; Calliphora vicina; NH4Cl prepulse; NHE; Na+/H+ antiporter; V-ATPase; blowfly; insect; intracellular pH; intracellular pH regulation; salivary gland; vacuolar H+-ATPase
Volume:215
Issue:8
Pagenumber:9
First Page:1337
Last Page:1345
Funder:Deutsche Forschungsgemeinschaft [Wa 463/9-5, Graduiertenkolleg 837 Functional Insect Science]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Biochemie und Biologie
Peer Review:Referiert