Figure 3. Small events are sodium dependent action potentials.
(A) Tetrodotoxin (TTX) abolishes sodium action potentials in Purkinje neurons (N = 3 cells). Representative trace from one cell in the absence (top trace) and presence (bottom trace) of 1 μM TTX. This cell rested at −60 mV. (B) QX-314 also abolishes sodium action potentials (N = 5 cells). Representative trace from one cell showing absence of sodium spikes. This cell rested at −53 mV. (C) Narrow sodium action potentials occur even in the presence of synaptic receptor blockers (N = 5 cells). Representative trace from one cell in the absence (top trace) and presence (bottom trace) of APV, CNQX and Bicuculline or Gabazine. This cell rested at −42 mV.
Figure 3—figure supplement 1. Sodium action potentials are recruited during depolarizing current injections (N = 5 cells in each condition).
Representative traces showing cellular response to the current injection protocol (grey, bottom panel) in control (top panel) and in the presence of QX-314 (middle panel). The cell in control rested at −52 mV and the cell in QX-314 rested at −53 mV.
Figure 3—figure supplement 2. Narrow spikes observed in the presence of synaptic receptor blockers are abolished by TTX.
(A) Representative traces from the same cell showing narrow spikes in the presence of synaptic receptor blockers (top trace) that are abolished with bath application of TTX (bottom trace). (B) Cellular response to current injection protocol (grey, bottom panel) showing both narrow and broad spikes being recruited in the presence of synaptic receptor blockers (top panel). Narrow spikes and not broad spikes are abolished by bath application of TTX (middle panel). This cell rested at −40 mV.