Oocyte Na+ Content
Water control and cRNA injected oocytes were incubated for 24 h in the ‘Na100’ solution as was used for electrophysiology recordings. Oocytes were removed to individual 1.5 mL microfuge tubes and washed briefly with double distilled H2O. All solution was removed from the tube and oocytes were stored at –20°C. Oocytes were thawed at room temperature before being homogenised in 0.1 M analytic nitric acid and digested at 42°C for 2 h. Nitric acid digested homogenates were diluted 1:10 with double distilled H2O, vortexed briefly and centrifuged at 16 000 x g (Beckman Coulter Microfuge® 16) to pellet cell debris. An aliquot of the supernatant was removed for dilution and ion analysis was performed using an Atomic Absorption Spectrophotometer (AAS; Shimadzu AA-7000) according to manufacturer’s instructions.