Whole cell conductance regulated by cytosolic [Cl-] and ADH-activated Cl- 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 cell currents as did dibutyryl cyclic AMP (5 mM). These transients consisted of two components: one was the non-selective cation conductance and the other was the Cl- conductance. The transient was evoked by AVT in the lower cytosolic Cl- concentration ([Cl-]i) (< approximately 50 mM), and was suppressed by higher concentrations of [Cl-]i (125 mM) in A6 cells. It seems likely that the [Cl-]i maintained at a lower level is an important requirement for A6 cells to respond to AVT.