Mechanisms of Cl−uptake through brush border membranes isolated from the posterior intestine of the freshwater trout,Oncorhynchus mykiss, R.

✍ Scribed by D. A. Colin; H. Aguenaou

• Book ID: 104738530
• Publisher: Springer-Verlag
• Year: 1992
• Tongue: English
• Weight: 588 KB
• Volume: 162
• Category: Article
• ISSN: 0174-1578
• DOI: 10.1007/bf00357527

✦ Synopsis

This paper presents a study of the mechanisms of CI-transport through the brush border membranes of the posterior part of the intestine in the freshwater trout, Oncorhynchus mykiss. The mechanisms for C1transport in the posterior intestine are distinct from those in the middle intestine; an inwardly directed pH gradient stimulates C1-uptake by brush border membrane vesicles, indicating a C1-/OH-exchange. A pH-regulated CI-conductance is present, which is not activated at normal intracellular pH. C1-uptake is stimulated by an outwardly directed HCO~ gradient revealing the presence of a C1-/HCO~-exchange but, conversely, C1is not exchanged against SO42-. In addition, carbonic anhydrase activities have been detected in both the intracellular and extracellular leaflets of the brush border membranes which favour the establishment of a bicarbonate gradient. A model of C1-transport mechanisms through the brush-border membranes of the posterior intestine of the freshwater trout is proposed.