FIGURE 7.

Effects of cAMP elevation on SOCE. Epifluorescence recordings of [Ca²⁺]_i in Fura-PE3-loaded large islet cells exposed to 250 μm of the K_ATP channel activator diazoxide. Apart from the size, the cells were identified as β-cells based on the lack of response to epinephrine (Epi, 5 μm). A, forskolin does not affect SOCE in a cell exposed to 3 mm glucose. VOCCs were blocked by hyperpolarization with diazoxide and presence of 100 μm methoxyverapamil. The [Ca²⁺]_i response to Ca²⁺ omission followed by exposure to 10 mm Ca²⁺ was studied under control conditions and in the presence of 5 μm forskolin before and after full activation of SOCE with 100 μm CPA. B, forskolin does not affect SOCE in a cell exposed to 20 mm glucose. Like in A, hyperpolarizing diazoxide and the voltage-operated Ca²⁺ channel blocker methoxyverapamil were present throughout. The [Ca²⁺]_i response to Ca²⁺ omission followed by exposure to 10 mm Ca²⁺ was studied under control conditions and in the presence of 5 μm forskolin before and after full activation of SOCE with 100 μm CPA.