Cl/HCO3 exchange in the basolateral membrane domain of rat jejunal enterocyte.
Basolateral membrane vesicles isolated from rat jejunal enterocyte and well purified from brush border contamination were tested to examine Cl and HCO3 movements. Uptake experiments provided no evidence for a coupling between Na and HCO3 fluxes; K-HCO3 and K-Cl cotransports also could be excluded. Transport studies revealed the presence of a Cl/HCO3 exchanger accepting other anions and inhibitable by the disulfonic stilbenes SITS and DIDS. We can exclude that the evidenced HCO3-dependent Cl uptake is due to brush border contamination, since in jejunal brush border membranes this mechanism, if present, has a very low transport rate. Besides the Cl/HCO3 antiporter, a Cl-conductive pathway seems to exist in jejunal basolateral membranes.
Orsenigo
M N
MN
Dipartimento di Fisiologia e Biochimica Generali, Università di Milano, Italy.
Tosco
M
M
Faelli
A
A
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000493:pharmacokinetics; D002352:Carrier Proteins / Q000502:physiology*; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D027963:Chloride-Bicarbonate Antiporters; D002712:Chlorides / Q000493:pharmacokinetics; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology; D007583:Jejunum / Q000166:cytology* / Q000502:physiology / Q000648:ultrastructure; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D001639:Bicarbonates; D002352:Carrier Proteins; D027963:Chloride-Bicarbonate Antiporters; D002712:Chlorides; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid