Measurement of cell volume changes in wild type and aquaporin transfected renal cells.

FORD, PAULA; RIVAROLA, VALERIA; CHARA, OSVALDO; PARISI, MARIO; CAPURRO, CLAUDIA

Bariloche - Argentina

Congreso; XXXIX Reunión de SAIB- XXXII Reunión de SAP- Bariloche Protein Symposium.; 2003

Sociedad Argentina de Investigaciones Bioquímicas

Measurement of water transport across cell membranes, with high temporal resolution and sensitivity, is essential for determining osmotic water permeability and changes in cell volume associated with stimulation or inhibition of ion transport mechanisms under isotonic conditions. Various techniques have been employed to study cellular volume changes. The use of fluorescent dye-dilution, based on an inversely proportional relationship between relative fluorescence intensity and relative cell water volume, provides excellent sensitivity for measuring volume changes in single cells. However the application of this technique in confluent monolayers of epithelial cells results on a directly proportional relationship, opposited to what was expected. These results were interpreted by other authors as a consequence of fluorescence self-quenching. In the present study, we investigated in detail whether this relationship depends on the region of the cell studied. To do this we used a cellular line established from rat cortical collecting duct (RCCD1), which maintains the cellular types and the transport characteristics of the native duct. We found that the relationship between relative fluorescence intensity and relative cell water volume does change with the region of the cell studied. Comparative studies between wild type and water channel (aquaporin-2 transfected) cells were made using this technique.