Figure 2. Time course of the effects of propofol and Intralipid on L-type calcium current at two different holding potentials. Upper panels show the original current tracings recorded at the time corresponding to that in lower panel. Holding potential was either at -90 mV (a and b) or at -40 mV (c and d). When double-pulse voltage protocol was used, membrane potential was depolarized from -90 mV first to -40 mV for a short time and then to +10 mV. Test potential was +10 mV and pulse duration was 300 ms. To monitor the resting block, no electrical stimuli were applied for the first 5 min in the presence of 56 micro Meter propofol. Afterwards, ICa(L) was recorded at different stimulation frequencies in the presence of propofol. Intralipid was present either alone or together with propofol (Diprivan), as indicated by the bars. The cell was dialyzed for 12 min before experiment started. Time 0 indicates the moment immediately after breaking the patch.