Effects of ion substitution on the transepithelial potential difference of the gills of the fiddler crab Uca tangeri : Evidence for a H super(+)-pump in the apical membrane

Transepithelial potential differences (PD sub(te)) and acidification rates of the bath chamber were measured on isolated perfused posterior gills of the fiddler crab Uca tangeri adapted to dilute seawater. It is concluded that under Cl super(-)-free conditions a rheogenic H super(+)-pump in the apical membrane is responsible for the ouabain-insensitive bath acidification as well as for the PD sub(te) .