Abstract
Intracellular Cl − activity (A Cl i) of the bullfrog choroidal epithelium has been studied using double-barreled Cl −-selective microelectrodes. microelectrodes. In bicarbonate-buffered saline, the brush-border membrane potential (V vc) was −43 mV, and A i Cl was 24 mM which was twice the predicted equilibrium activity. The uphill Cl − accumulation required the presence of external Na + and was inhibited by furosemide added to the basolateral side. Removal of HCO − 3 from the bath solution increased A i Cl. On addition of 3-isobutyl-1-methyl-xanthine (IBMX), V vc depolarized, and A i Cl approached the equilibrium activity. It is concluded that net Cl − secretion by the choroidal epithelium is mediated by a furosemide-sensitive, Na +-coupled Cl − uptake mechanism at the basolateral border and a Cl − conductive pathway at the brush border membrane. The results suggest that intracellular cAMP either increases the Cl − conductance of the epithelial membranes and/or inhibits the NaCl co-transport mechanism.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
