WHOLE-CELL CONDUCTANCE REGULATED BY CYTOSOLIC [CL-] AND ADH-ACTIVATEDCL- CHANNELS IN A DISTAL NEPHRON CELL-LINE (A6)

The effect of antidiuretic hormone (ADH) on a distal nephron cell line (A6) was studied using the whole cell patch clamp technique. Arginine vasotocin (AVT, 140mU/ml) evoked a ''transient'' increase in whole ce ll currents as did dibutyryl cyclic AMP (5 mM). These transients consi sted of two components: one was the non-selective cation conductance a nd the other was the Cl- conductance. The transient was evoked by AVT in the lower cytosolic Cl- concentration ([Cl-](i)) (< similar to 50 m M), and was suppressed by higher concentrations of [Cl-](i) (125 mM) i n A6 cells. It seems likely that the [Cl-](i) maintained at a lower le vel is an important requirement for A6 cells to respond to AVT.