Regulation of Na-Cl absorption in rabbit proximal colon in vitro
Sellin, J.H.; De Soignie, R.
American Journal of Physiology 252(1 Pt 1): G45-G51
1987
ISSN/ISBN: 0002-9513 PMID: 3812687 Document Number: 289144
To characterize the regulation of sodium-chloride transport, the effects of specific adrenergic agonists on ion fluxes in short-circuit conditions were tested in rabbit proximal colon (PC) in vitro. The effects of the transport inhibitors bumetanide, furosemide and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulphonic acid were also tested. Na-Cl cotransport in rabbit PC was primarily under alpha 2-adrenergic control. The alpha 2-blocker yohimbine at high concentrations acted as an agonist in PC. alpha 2-Adrenergic agonists stimulated Na-Cl absorption in rabbit ileum and PC. In PC, however, the process was electrically quiet and therefore did not seem to be associated with electrogenic HCO3 secretion as found in ileum. The lack of effect of bumetanide, furosemide and removal of potassium on Na transport suggests that a single Na-Cl (or Na-K-2Cl) carrier is not involved in Na-Cl cotransport in proximal colon.