Figure 5.

Representative recordings of PER2::LUC bioluminescence from fibroblast cultures in various Ca²⁺ concentrations (A). Fibroblasts were cultured in HMM with 0 (dashed line), 1.8 (control, gray line), or 3.6 mM Ca²⁺ (black line). Fibroblasts showed clear circadian rhythms in all cases. (B) Brightness relative to 1.8 mM Ca²⁺ control. Amplitudes relative to control (C), periods (D), and phases (E) of samples categorized as rhythmic. Fibroblasts were increased in number in HMM with 3.6 mM Ca²⁺ and decreased in 0 mM Ca²⁺ (F). Columns show average values ± SE. Numbers of cultures are indicated by white numerals within columns. ns, not significant; *p < 0.05, **p < 0.01 compared to control (ANOVA followed by Dunnett’s test).