ISSN:
1432-136X
Keywords:
H+-pump
;
Crab gills
;
Uca tangeri
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary 1. Transepithelial potential differences (PDte) and acidification rates of the bath chamber were measured on isolated perfused posterior gills of the fiddler crabUca tangeri adapted to dilute seawater. 2. The PDte decreased to almost zero when Na+ was substituted by choline or when ouabain was added to the perfusion saline in high concentrations (10 mmol·l−1). Thus, the rheogenic NaCl-transport across the gill epithelium seems to be totally Na+-dependent. 3. When Cl− was replaced by gluconate, a bath positive PDte occurred which was insensitive to ouabain. This PDte could also be observed when, in addition to Cl− removal, Na+ was replaced by TMA+. 4. Bath acidification under normal conditions could be abolished by ouabain, indicating that there is H+ excretion via electrically silent Na+/H+ exchange. In contrast, bath acidification under Cl−-free conditions is only partially blocked by ouabain. 5. It is concluded that under Cl−-free conditions a rheogenic H+-pump in the apical membrane is responsible for the ouabain-insensitive bath acidification as well as for the PDte.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00692682
