Fig. 7.
Inward currents through voltage-dependent Na+ channels (INa) and through nicotinic receptor channels (IACh) were not affected by CCCP.A shows the time course of peak INaelicited by 16 msec depolarizing test pulses to −10 mV, applied at 15 sec intervals to a cell voltage clamped at −80 mV. The cell was superfused with an extracellular solution containing 137 mmNa+ and 0 mm Ca2+ and dialyzed with an intracellular EGTA-free solution. CCCP was superfused as shown by the black horizontal bar. Insets show original traces taken immediately before (control), at 90 sec of superfusion with CCCP, and 2 min after washout of CCCP. Similar results were obtained in the other nine cells; averaged values ofINa for all cells are given in Results. The stimulation protocol for recording of IACh is shown at the top of B. The cell was voltage clamped at −80 mV, and then stimulation was applied at 120 sec intervals as follows. First, a 1 sec depolarizing pulse to +20 mV was applied, and then, after 300 msec, an acetylcholine (ACh) pulse of 500 msec duration was given. Typical current traces obtained before (control) and at the 90 sec of superfusion with 2 μm CCCP are shown.