Figure 8.

Whole-cell recording causes a time-dependent increase in the amplitude of ramp-evoked currents and Na⁺ transients, which is reduced by spermine. A, Whole-cell ramp-evoked current and Na⁺ elevations in soma (black) and AIS (red) at 2 and 10 min after break-in to the cell. Notice that the amplitude of both I_NaP and of Na⁺ transients increased as a function of recording time. B, Pseudocolor maps of the ramp elicited ΔF/F changes between the times marked by the arrowheads in A at the second and tenth minute after the break-in. C, In whole-cell recording with exogenous spermine (2 mm) in the pipette, the amplitude of ramp-evoked I_NaP and of Na⁺ transients remained relatively stable during the 10 min period after the break-in. D, Pseudocolor maps of the ramp elicited ΔF/F changes between the times marked by the arrowheads in C at the second and tenth minute after the break-in with spermine-containing pipette. E, Averaged (n = 8) I_NaP amplitudes at −35 mV as a function of time after break-in with pipettes containing control (black squares), 1 mm (open squares), and 2 mm spermine (open circles). F, Averaged (n = 8) peak amplitudes of the somatic ΔF/F transients as a function of time after break-in with a control or spermine-containing pipette. G, Averaged (n = 8) peak amplitudes of the AIS ΔF/F transients as a function of time after break-in with a pipette containing control or spermine.