Figure 6

Measurement of intracellular [Ca²⁺] and [Ca²⁺] secretory index.

After treatment with 1 mM caffeine for 3-h, intracellular and secretory [Ca²⁺] contents were measured using a method based on Arsenazo III-calcium reaction (see details in “Materials and Methods”). (A) Intracellular [Ca²⁺]; (B) [Ca²⁺] secretory index was calculated using Equation 3: [Ca²⁺] secretory index = ([Ca²⁺]_{Sample Sup} − [Ca²⁺]_MEM)/[Ca²⁺]_MEM × 100. Each bar represents mean ± SEM from 3 independent experiments. *p < 0.05 vs. control.