Figure 6. Voltage and Ca2+ current dependence of the depolarization-evoked currents.
A and B, paired (100 ms apart) 2 ms depolarizations from −84 mV to a variable potential were given every second. The initial step voltage was −44 mV and was increased to −20 mV in 2 mV increments. The same protocol was applied in the absence then in the presence of 50 μmdl-tBOA (local puff starting 10 s before the 2nd protocol). The dl-tBOA-sensitive currents evoked by the first depolarization are shown in A, those by the paired depolarization in B. C, normalized peak amplitude as a function of the depolarization voltage (n = 5–7 depending on voltage). D, the depolarization-evoked transient current is blocked by a local application of 100 μm Cd2+ (dark grey trace). Puff duration was 15 s; the Cd2+ effect was washable (light grey trace).