spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by THOMSON, R. B.
Right arrow Articles by PHILLIPS, J. E.
Right arrow Search for Related Content
PubMed
Right arrow Articles by THOMSON, R. B.
Right arrow Articles by PHILLIPS, J. E.
Journal of Experimental Biology 155,455-467 (1991)
Published by Company of Biologists 1991

Acid-Base Transport and Control in Locust Hindgut: Artefacts Caused by Short-Circuit Current

R. BRENT THOMSON 1, N. AUDSLEY 1, and JOHN E. PHILLIPS 1

1 Department of Zoology, University of British Columbia, Vancouver, BC, V6T 2A9, Canada

To whom reprint requests should be directed

The commonly used method of passing short-circuit current (Isc) across insect epithelia through Ag-AgCl electrodes, without the use of salt bridges, leads to significant OH- production at the cathode (lumen side) when high currents are applied.

The alkalization of the lumen previously reported when cyclic AMP was added to short-circuited locust hindgut is a result of this phenomenon rather than cyclic-AMP-mediated stimulation of acid-base transport in the hindgut.

When salt bridges are used to pass short-circuit current across locust hindgut, acid secretion (JH) into the lumen equals alkaline movement (JOH) to the haemocoel side, and JH is similar under both open- and short-circuit conditions. JH is similar (1.5 µequiv cm-2 h-1) in recta and ilea.

Addition of cyclic AMP inhibits JH across the rectum by 42–66%, but has no effect on the ileum when salt bridges are used.

Electrical parameters (Isc, Vt, Rt) reflecting hindgut Cl- transport (JCL) before and after stimulation with cyclic AMP are the same whether or not salt bridges are used. We found no evidence of any coupling between JCl and JH/JOH.

Key words: H+ secretion, locust, rectum, ileum, cyclic AMP, epithelia

Accepted on August 13, 1990






© The Company of Biologists Ltd 1991