Spikelets recorded in the presence of the sodium channel blocker, QX-314, in the patch pipette. (A) Action potentials from the recorded cell (A1) were eliminated with QX-314 (5 mM, A2) in the patch pipette. This trace was the first response to depolarizing current after obtaining the whole-cell recording (i.e., thus, no pre-baseline), and the last response with action potentials. (B) In the presence of QX-314 and low concentrations of 4-AP (500 μM), spikelets (arrows) were clearly detectable from the noise (B2) and were suppressed by bath application of tetrodotoxin (1 μM, B2). Membrane potential was held at −70 mV.