Different Membrane Pathways Mediate Ca²⁺ Influx in Adrenal Chromaffin Cells Exposed to 150–400 ns Electric Pulses

Figure 4

Peak Ca²⁺ responses evoked by a 150, 200, and 400 ns pulse at different -field amplitudes. The plot in (a) represents the average ± SE for the maximal increase in for each pulse duration at -field amplitudes ranging from 0.9 to 3.1 kV/cm ( 5–40). The arrows indicate the -field amplitude at which there was no response. A regression analysis of peak Ca²⁺ responses for each pulse duration at -field amplitudes ranging from 1.9 to 8.7 kV/cm is shown in (b) for a 150 ns pulse ( 5–40); in (c) for a 200 ns pulse ( 5–26); and in (d) for a 400 ns pulse ( 5–15). All slopes in panels (b)–(d) were significantly different from 0.

(a)

(b)

(c)

(d)