Fig. 5. Store-operated influx of Mn²⁺ in response to CPA in an individual ß-cell. Pancreatic ß-cells were loaded with fura-2 in hyperpolarizing medium containing 400 µM diazoxide, 20 mM glucose and 1.28 mM Ca²⁺. The same medium lacking indicator but containing 50 µM methoxyverapamil was present at the beginning of the experiment. The medium was then supplemented with 400 µM Mn²⁺ (upper bar) and 2 or 20 µM CPA (lower bars) as indicated. The cytoplasmic Mn²⁺ concentration (A) is shown above [Ca²⁺]_i (B), which is not reliable after the introduction of Mn²⁺ (shaded area). The broken lines indicate the rate of change in Mn²⁺ concentration immediately after addition of Mn²⁺ (1) and after subsequent addition of 2 (2) and 20 µM CPA (3). The results are representative of five independent experiments.