Fig. 9. 2-APB inhibits store-operated influx of Mn²⁺ in response to carbachol 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 200 µM Mn²⁺ (upper bar), 100 µM carbachol (Carb; middle bar) and 100 µM 2-APB (lower bar). 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), after subsequent addition of 100 µM carbachol (2) and 100 µM 2-APB (3). The results are representative of ten independent experiments.