Figure 3

Ca²⁺ oscillation profiles and mass content in each subcellular compartment at different levels of IP₃ stimulation. (A,B) Ca²⁺ oscillations in ER, Mt, and effective Cyt due to an IP₃ stimulus of 0.2 µM (A; region α) and 0.7 µM (B; region β) applied at 50 s. Initial/basal Ca²⁺ levels in each compartment were the same in regions α and β. (C,D) Total Ca²⁺ content in each compartment (in femtomoles) is shown for region α (C) and β (D) and percentages following IP₃ stimulation are reported in corresponding insets. Prior to IP₃ stimulation, the majority of total Ca²⁺ content is stored in the ER. Following IP₃ stimulation, ER-released Ca²⁺ is channeled to the Cyt and Mt at percentages that depend on the IP₃ level.