Fig. 3.

Characterization of depolarization-induced NT-3 gene expression. Embryonic Xenopus muscle cells were cultured for 3 d and then treated with the depolarizing agents veratridine or K⁺ and harvested for NT-3 mRNA measurement with RT-PCR assay, as described in Figure 2. Top, Time course of NT-3 gene expression induced by depolarization. KCl (35 mm) or veratridine (10 μm) was applied to the cultures at time 0 (control). The muscle cells were harvested at different time points after depolarization. The experiments were performed three times (n = 3), and the results were virtually identical. A typical result is shown.Bottom, Concentration dependence of veratridine effects. The muscle cultures were treated for 2 hr with different concentrations of veratridine, as indicated. Control, no veratridine treatment;n = 3.