Confocal microscopy showing apical localization of pannexin 1 (PANX-1) channel and P2X7 receptor in principal cells (PCs) of the mouse epididymis. 3D reconstruction of confocal microscopy images for PANX-1 channel (A; left panel) and ATP-gated P2X7 receptor (B; left panel) labelled in red in the mouse epididymis. V-ATPase-positive clear cells (CCs), which specifically express EGFP under the promoter of the B1 subunit (B1-VATPase), can be visualized in green. Both PANX-1 and P2X7 are enriched in the apical membrane of PC (arrows, EGFP-negative cells). PANX-1 and P2X7 labeling was abolished when the antibody was preincubated with the immunizing peptide (right panels). Nuclei are labelled with DAPI in blue. Images were acquired with a 20X/0.8 objective. (Left panels) Each box = 20 µm². (Right panels) Scale bars = 20 μm.