Fig. 6. The chloride channel blocker DPC depresses basal secretion and reduces the effect of (A) 10 µmol l^–1 Tenmo-ADFb (+ADFb) and (B) 1 nmol l^–1 Achdo-KII (+AKII). Bars represent the means + 1 s.e.m. for the number of replicates shown in parentheses. Tubules were held in control saline (open bars) or moved to a saline containing 0.2 mmol l^–1 DPC in the first experimental period (+DPC; solid bars). Identical letters indicate significant differences between mean rates of secretion (P<0.01).