The tip resistance of the electrode was 3 to 7 MΩ when filled with intracellular solution containing (in mM) potassium gluconate 120, NaCl 6, CaCl 2 1, MgCl 2 2, MgATP 2, NaGTP 0.5, phosphocreatine Na 2 12, EGTA 5 and HEPES hemisodium 10 (pH 7.3 as adjusted with KOH; osmolarity 285–290 mOsmol/L).
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