Effect of NaAsO2 on the heart rhythm of WT and AQP9-null mice. (A) Representative electrocardiograms from WT and AQP9-null mice taken at 0-, 5-, and 7-h time points after 10 mg/kg NaAsO2 injection. Six WT and five AQP9-null mice were monitored. (B) Serum concentration of Na+, K+, Cl−, and Ca2+ in WT and AQP9-null mice 24 h after NaAsO2 injection. Samples were analyzed from four WT and four AQP9-null mice. Error bars represent SEM.