For inside-out recordings both the pipette and bath solution were composed of (mM): KCl 160 mM, MgCl2 1 mM, HEPES 10 mM, EGTA 1 mM; pH 7.4 with KOH.
For the experiments, the oocytes were bathed in Na+ buffer composed of (mM): 100 NaCl, 2 KCl, 1 MgCl2, 1 CaCl2, 10 Hepes/Tris, pH 7.4, and in Na+-free buffer where choline-Cl replaced NaCl.
The pipette solution with the high Cl− concentration was composed of (mM): 120 KCl, 30 NaCl, 1 MgCl2, 0.5 CaCl2, 5 EGTA, 2 Mg-ATP, 10 HEPES, pH 7.3 adjusted with Tris-base.
Pipette solution for these recordings was composed of (mM): KCl 125.0, CaCl2 1.0, MgCl2 1.0, EGTA 11.0, HEPES 10.0, sucrose 10.0, adjusted to pH 7.2 with KOH.
For current-clamp recordings, bath solution was composed of (mM): NaCl 143.0, Na2HPO4 0.25, KCl 5.4, CaCl2 1.8, MgCl2 0.5, glucose 5.6, HEPES 5.0, adjusted to pH 7.35 with NaOH.
Small aliquots of the cell suspension were transferred to the experimental chambers and diluted with PSS composed of (mM): NaCl 120, KCl 6, CaCl2 2.5, MgCl2 1.2, glucose 12, HEPES 10; pH adjusted to 7.4 with NaOH.
For recordings, neurons were bathe in an extracellular solution composed of 140 mM NaCl/3 mM KCl/2 mM CaCl2/10 mM HEPES/1 μM tetrodotoxin (TTX /20 mM dextrose, pH 7.35.
This solution was further diluted to a final concentration of 1 mM in a solution composed of 125 mM NaCl, 5 mM KCl, 10 mM glucose, 10 mM HEPES, 2 mM CaCl2, 2 mM MgSO4, and 0.2 mM sulforhodamine 101 (SR101).
The alkaline trace element solution was composed of 0.1 mM Na2SeO3; 0.1 mM Na2WO4; 0.1 mM Na2MoO4 and 10 mM NaOH.
The bathing Ringer's solution was composed of 120 mM NaCl, 25 mM NaHCO3, 3.3 mM KH2PO4, 0.8 mM K2HPO4, 1.2 mM MgCl2, 1.2 mM CaCl2, and 10 mM glucose.
Vesiculation buffer is composed of 200 mM NaCl, 5 mM KCl, 0.5 mM MgCl2, 0.75 mM CaCl2, and 100 mM bicine, pH 8.5.
