Fig. 8. Effect of 2-APB on elevation of [Ca2+]i due to store-operated and voltage-dependent influx of Ca2+ in individual ß-cells. Pancreatic ß-cells were loaded with fura-2 in hyperpolarizing medium containing 400 µM diazoxide, 20 mM glucose and 1.28 mM Ca2+ (A,B) or in medium containing 3 mM glucose and 1.28 mM Ca2+ (C,D). The same medium lacking indicator but containing 50 µM methoxyverapamil was present at the beginning of the experiments shown in A and B, whereas there was no further additive in C and D. 100 µM 2-APB was present as indicated by the upper bars. Ca2+ was omitted and 2 mM EGTA added during the periods shown by the middle bars. The presence of 100 µM carbachol (Carb), 50 µM CPA and 31 mM K+ are shown by the lower bars. The results are representative of five (A), six (B), four (C) or three (D) independent experiments.
