A CHARACTERIZATION OF THE CHLORIDE CONDUCTANCE IN MESANGIAL CELLS FROM THE H-2K(B)-TSA58 TRANSGENIC MOUSE

The chloride conductance of conditionally immortalized mesangial cells isolated from the H-2K(b)-tsA58 transgenic mouse was studied in cells grown in permissive and non-permissive culture conditions. No differences were found in the magnitude of the chloride conductance in 140 mM tetramethyl ammonium chloride between cells grown in permissive and non-permissive culture conditions (1.08 +/- 0.05 nS and 1.02 +/- 0.05 nS). Selectivity sequences were defined as 1.8I(-)> 1.2Br(-)> 1Cl(-) and 1.3I(-)> 1.1Br(-)> 1Cl(-) respectively and both the anion channel inhibitors niflumic acid and ochratoxin A inibited the chloride conductance in a dose-dependent manner. The chloride conductance was made up from calcium-dependent and calcium-independent components and in the presence of 1 mu M free calcium in the pipette this could be increased by the presence of 100 U ml(-1) insulin added to the incubation medium. This appeared to increase the sensitivity of the conductance to levels of intracellular calcium as no differences were observed in the presence of either I mM or 100 nM pipette calcium. These data indicate that there is a significant chloride conductance in mesangial cells from the H-2K(b)-tsA58 transgenic mouse and minimal changes are observed with changes from permissive to non-permissive culture conditions.