AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 1 44-G49, Copyright © 1986 by American Physiological Society
Concentration-dependent effects of disulfonic stilbenes on colonic chloride transport
P. L. Smith, S. K. Sullivan and R. D. McCabe
Stripped rabbit colonic mucosa was studied in vitro in Ussing chambers to
determine effects of the disulfonic stilbenes
4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonate (SITS) and
4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) and the diuretic
furosemide on unidirectional and net Cl fluxes. Results from these studies
reveal that SITS (1 mM) added to either the serosal or mucosal bathing
solution reduced both unidirectional Cl fluxes with no significant change
in net Cl flux. The effects of SITS do not appear to be mediated by an
effect on the shunt permeability since SITS (1 mM) did not alter either the
intercept or slope of the Na concentration dependence of the
serosal-to-mucosal Na flux. Furosemide (1 mM) decreased the
serosal-to-mucosal Cl flux without altering short-circuit current (Isc)
when added to the luminal bathing solution and reduced both unidirectional
fluxes and increased Isc when added to the serosal bathing solution. DIDS
(0.5 mM) added to the luminal bathing solution did not alter unidirectional
Cl fluxes or Isc. However, serosal addition of DIDS produced dose-dependent
changes in Cl transport. At 5 microM DIDS reduced the mucosal-to-serosal Cl
flux without altering the serosal-to-mucosal flux or Isc. At 50 microM DIDS
reduced the mucosal-to-serosal Cl flux and increased Isc, and at 0.5 mM
DIDS increased the serosal-to-mucosal Cl flux, reduced the
mucosal-to-serosal Cl flux, and increased Isc and transepithelial
conductance. The effect of 0.5 mM DIDS on Isc was reduced by Ca removal
from the serosal bathing solution and by the loop diuretics furosemide and
bumetanide.(ABSTRACT TRUNCATED AT 250 WORDS)
