Inhibition by cAMP of Calcium-Activated Chloride Currents in Cultured Sertoli Cells from Immature Testis

• DOI: 10.1007/s002329900528
• Publication Date: 2002-07-25T02:58:49Z
• Authors: N. Lalevée; M. Joffre
• Keywords: Pipette; EGTA; Niflumic acid; DIDS; Ionomycin; Ruthenium red; Tetraethylammonium

We have characterized a Ca2+-dependent Cl- current (ClCa) in cultured Sertoli cells from immature rat testis by using the whole cell recording patch-clamp technique. Cells dialyzed with pipette solutions containing 3 mm adenoside-triphosphate (ATP) and 1 microM free Ca2+, exhibited outward currents which were inhibited by 4, 4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) and anthracene-9-carboxylic acid (9-AC) but insensitive to tetraethylammonium (TEA). Dialysis of cells with pipette solutions containing less than 1 nm free Ca2+ strongly reduced the currents indicating that they were Ca2+ dependent. With cells dialyzed with Cs+ glutamate-rich pipette solutions containing 0.2 mm EGTA, 10 microM ionomycin induced outward currents having properties of Ca2+-activated Cl- currents. With ATP-free pipette solution, the magnitude of currents was not modified suggesting the direct control by Ca2+. By contrast, addition of 0.1 mm cAMP in the pipette solution or the superfusion of cells by a permeant analogue of cAMP strongly reduced the currents. These results may suggest that ClCa is inhibited by cAMP-dependent protein kinase. Finally, our results do not agree with the model of primary fluid secretion by exocrine cells, but are in agreement with a hyperpolarizing effect of cAMP in primary culture of Sertoli cells and the release of a low Cl- and bicarbonate-rich primary fluid by these cells.