Fig. 2.

Comparison of Ca²⁺ transients evoked by 10- and 60-ns stimuli. Each trace is the average from at least 15 cells; nsEP was applied at 60 s. The nsEP intensity (kV/cm) was adjusted to evoke similar responses by 10- and 60-ns stimuli in the presence of 2 mM external Ca²⁺ (red traces). The fraction of Ca²⁺ coming from the endoplasmic reticulum (ER) was assessed by applying the same nsEP in the absence of external Ca²⁺ (blue traces). Note that 10-ns pulses consistently evoked higher ER response than 60-ns ones. See text for further details.