FIGURE 2.

Changes in local Ca²⁺ influx impact upon c-fos expression. A, Ca²⁺ signals in response to 2 μm thapsigargin in 2 mm Ca²⁺ (normal) are compared with those seen in the presence of 10 mm Cs⁺ and 10 mm TEA⁺, to block inwardly rectifying K⁺ channels. B, c-fos expression was significantly reduced, compared with thapsigargin (Thap.) stimulation, when cells were stimulated with thapsigargin and Cs⁺/TEA⁺. Aggregate data from three independent experiments are shown in the bottom panel. Both thapsigargin groups were significantly different from the resting group and from each other (p < 0.01, ANOVA). C, Ca²⁺ signals following stimulation with thapsigargin in different external Ca²⁺ concentrations (0.25, 0.5, and 2 mm) are compared. D, c-fos expression is compared for the different conditions. Aggregate data from four independent experiments are depicted in the histogram. Data have been normalized to control (non-stimulated levels). Differences between each data set were significant (p < 0.01, ANOVA). There was a significant difference between thapsigargin/2 Ca²⁺ and thapsigargin/0.5 Ca²⁺ (p < 0.01, ANOVA).