Fig. 3.

Effect of ATP on low-conductance K⁺ channels in the apical membrane of mouse cortical collecting duct. Patch-clamp techniques were applied to split-open tubules. a Channel recording showing that addition of ATP (100 µM) to the bathing solution (grey band) caused closure of the K⁺ channel, an effect that was reversible. b Dose–response curve for the effect of ATP on K⁺ channel open probability. The action of ATP was blocked by the P2 receptor antagonist suramin and was mimicked by UTP, whereas αβMeATP and 2MeSATP were without effect on K⁺ channel activity, suggesting the involvement of P2Y₂ receptors. Taken, with permission, from Lu et al [40]