Fig. 3. 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) and 3.6 or 30 µM carbachol (Car; lower bars). 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 3.6 (2) and 30 µM carbachol (3). The results are representative of three independent experiments.