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

First published online March 31, 2007
Journal of Experimental Biology 210, 1463-1471 (2007)
Published by The Company of Biologists 2007
doi: 10.1242/jeb.001529

This Article Figures Only Full Text Full Text (PDF) 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 Hille, C. Articles by Walz, B. Search for Related Content PubMed PubMed Citation Articles by Hille, C. Articles by Walz, B. Social Bookmarking                         What's this?

A vacuolar-type H⁺-ATPase and a Na⁺/H⁺ exchanger contribute to intracellular pH regulation in cockroach salivary ducts

Carsten Hille^* and Bernd Walz

University of Potsdam, Institute of Biochemistry and Biology, Department of Animal Physiology, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam-Golm, Germany

Author for correspondence (e-mail: walz{at}uni-potsdam.de)

Accepted 12 February 2007

Cells of the dopaminergically innervated salivary ducts in the cockroach Periplaneta americana have a vacuolar-type H⁺-ATPase (V-ATPase) of unknown function in their apical membrane. We have studied whether dopamine affects intracellular pH (pH_i) in duct cells and whether and to what extent the apical V-ATPase contributes to pH_i regulation. pH_i measurements with double-barrelled pH-sensitive microelectrodes and the fluorescent dye BCECF have revealed: (1) the steady-state pH_i is 7.3±0.1; (2) dopamine induces a dose-dependent acidification up to pH 6.9±0.1 at 1 µmol l^–1 dopamine, EC₅₀ at 30 nmol l^–1 dopamine; (3) V-ATPase inhibition with concanamycin A or Na⁺-free physiological saline (PS) does not affect the steady-state pH_i; (4) concanamycin A, Na⁺ -free PS and Na⁺/H⁺ exchange inhibition with 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) each reduce the rate of pH_i recovery from a dopamine-induced acidification or an acidification induced by an NH₄Cl pulse; (5) pH_i recovery after NH₄Cl-induced acidification is almost completely blocked by concanamycin A in Na⁺-free PS or by concanamycin A applied together with EIPA; (6) pH_i recovery after dopamine-induced acidification is also completely blocked by concanamycin A in Na⁺-free PS but only partially blocked by concanamycin A applied together with EIPA. We therefore conclude that the apical V-ATPase and a basolateral Na⁺/H⁺ exchange play a minor role in steady-state pH_i regulation but contribute both to H⁺ extrusion after an acute dopamine- or NH₄Cl-induced acid load.

Key words: vacuolar H⁺-ATPase, V-ATPase, NHE, BCECF, intracellular pH, dopamine, biogenic amines, insect, cockroach, Periplaneta americana, salivary glands

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				C. Rotte, J. Witte, W. Blenau, O. Baumann, and B. Walz Source, topography and excitatory effects of GABAergic innervation in cockroach salivary glands J. Exp. Biol., January 1, 2009; 212(1): 126 - 136. [Abstract] [Full Text] [PDF]

				C. Hille and B. Walz Characterisation of neurotransmitter-induced electrolyte transport in cockroach salivary glands by intracellular Ca2+, Na+ and pH measurements in duct cells J. Exp. Biol., February 15, 2008; 211(4): 568 - 576. [Abstract] [Full Text] [PDF]