FIGURE 1.

Local Ca²⁺ entry activates c-fos expression. A, Ca²⁺ signals evoked by thapsigargin (2 μm) are shown for the various conditions. B, gene expression evoked by thapsigargin (Thap.) is compared in 2 Ca²⁺, 0 Ca²⁺, and 0 Ca²⁺ plus La³⁺. Top panel, typical gel; bottom panel, aggregate data from four experiments. The only stimulation protocol that differed from the control (non-stimulated) state was thapsigargin in 2 mm Ca²⁺ (p < 0.01, ANOVA). c-fos expression has been normalized to the control level.