Fig. 3. After treatment with latrunculin B, IP₃Rs remain localized in the same region as the residual actin in the apical subplasmalemmal compartment of pancreatic acini. Isolated pancreatic acinar cell clusters were treated with 100 µM latrunculin B for 30 minutes to 1 hour and then fixed and stained with (A) phalloidin, (B) antibodies to actin (mAb, green) and IP₃R2 (pAb, red), or (C) antibodies to actin (pAb, green) and IP₃R3 (mAb, red). Images are of confocal sections taken through the middle of the cell clusters. Arrows denote the apical membrane and arrowheads denote the basolateral membrane. Lower panels represent enlarged images of the regions covered by squares. Bar, 10 µm for images of cell clusters and 2 µm for magnified image.