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 Similar articles in PubMed
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 Diaz,, M.
Right arrow Articles by Bolanos, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Diaz,, M.
Right arrow Articles by Bolanos, A.

Journal of Experimental Biology, Vol 186, Issue 1 9-22, Copyright © 1994 by Company of Biologists

JOURNAL ARTICLES

EFFECTS OF BARIUM CHLORIDE ON ELECTROLYTE TRANSPORT ACROSS ISOLATED COLONS FROM NORMAL AND ALDOSTERONE-TREATED LIZARDS (GALLOTIA GALLOTI)

M. Diaz,, A. Lorenzo, T. Gomez, P. Badia and A. Bolanos

Addition of BaCl2 to the solution bathing colons of normal lizards did not alter the absorptive Na+ flux, but did reverse the net absorption of Cl- to become net secretion. Cl- secretion resulted from an increase in its serosal- to-mucosal movement and was positively correlated to an increase in short- circuit current. Ba2+-induced short-circuit current was dependent on the presence of both Na+ and Cl- in the serosal medium. Ba2+-induced Cl- secretion could be reversed by serosal amiloride (10-4 mmol l-1). Colons from acutely or chronically aldosterone-treated lizards exhibited a considerably higher short-circuit current, potential difference and net Na+ absorption than did untreated colons. Net Cl- transport was unaltered by acute treatment, but was totally abolished after chronic treatment. BaCl2 rapidly decreased the potential difference, short-circuit current and tissue conductance across colons from aldosterone-treated lizards. Net Na+ transport was markedly inhibited by Ba2+ in both acutely and chronically treated tissues, but barium did not change unidirectional or net Cl- fluxes in these. The present results support the following hypotheses: (1) that BaCl2 inhibits electrogenic Na+ absorption induced by acute or chronic aldosterone treatment and (2) that Ba2+ induces an electrogenic Cl- secretion by stimulating a basolateral Na+-dependent Cl- intake in normal but not in aldosterone-treated colons. This also suggests that aldosterone could exert an antisecretory influence in colonic epithelia.




© The Company of Biologists Ltd 1994