Pharmacological dissection of AHP currents

For dissection of AHP currents, the intrapipette solution contained KCl, 60 mM; K-gluconate, 73 mM; MgSO₄, 1 mM; HEPES, 10 mM; EGTA, 0.1 mM; Mg-ATP, 4 mM; and Na₂-GTP, 0.3 mM (pH 7.35 and 285 mOsm). TTX (0.5 μM), apamin (0.1 μM) and/or NFA (100 μM) were applied after achieving the whole-cell configuration. The bath solution was treated with TTX for recordings of Ca²⁺-dependent AHP currents and was perfused with TTX and apamin in order to obtain apamin-sensitive K⁺ currents. For dissection of NFA-sensitive anion currents, recording aCSF was perfused with TTX, apamin and NFA. Apamin-sensitive K⁺ currents and NFA-sensitive anion currents were calculated by trace subtraction.