Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-19924
Pflugers Arch 1995 Apr 01;4296:859-69. doi: 10.1007/bf00374811.
Show Gene links Show Anatomy links

Expression of the human sodium/proton exchanger NHE-1 in Xenopus laevis oocytes enhances sodium/proton exchange activity and establishes sodium/lithium countertransport.

Busch S , Burckhardt BC , Siffert W .


???displayArticle.abstract???
We investigated whether the human sodium/proton (Na+/H+) exchanger isoform 1 (NHE-1) can mediate sodium/lithium (Na+/Li+) countertransport. Using the Xenopus laevis oocyte expression system we determined amiloride-sensitive Li+ uptake, a measure of Na+/H+ exchange, in oocytes injected with water or NHE-1 cRNA. Amiloride-sensitive Li+ uptake was three- to tenfold enhanced over control in NHE-1 cRNA-injected cells and was selectively inhibited by 0.01 microM HOE 694 [i.e. (3-methylsulphonyl-4-piperidinobenzoyl) guanidine methanesulphonate]. The endogenously present Na+/H+ exchanger was insensitive to HOE 694. After acidification of oocytes from pH 7.7 to 6.8, amiloride-sensitive Li+ uptake was four- to tenfold higher in NHE-1 cRNA-injected cells than in controls. Li+ efflux from control oocytes was independent of extracellular Na+, indicating that these cells expressed no measurable Na+/Li+ countertransport activity. In NHE-1 cRNA-injected oocytes, Li+ efflux was distinctly enhanced by extracellular Na+ ions. This Na(+)-dependent Li+ efflux was inhibited by ethylisopropylamiloride, phloretin and by cytosolic acidification. The data show that expression of the NHE-1 in X. laevis oocytes induces the expression of Na+/Li+ countertransport. The data confirm that Na+/H+ exchange and Na+/Li+ countertransport are mediated by the same transport system.

???displayArticle.pubmedLink??? 7603840
???displayArticle.link??? Pflugers Arch


Species referenced: Xenopus laevis
Genes referenced: slc9a1

References [+] :
Aronson, Kinetic properties of the plasma membrane Na+-H+ exchanger. 1985, Pubmed