Figure 1.

Thin cryosections (1 μm) of rat kidney immunolabeled with anti-AQP1 and counterstained with peroxidase. (A) Cortex contains proximal tubules with abundant immunolabeling of the apical brush border (arrowhead) and basolateral plasma membranes with infoldings (arrows). Other nephron segments including distal-convoluted tubules (D) failed to label. (B) Inner medulla contains descending thin limbs that exhibit extensive immunolabeling of both apical (arrowhead) and basolateral (arrow) plasma membranes domains. Vascular structures, ascending thin limbs (∗), and collecting ducts (C) failed to label. ×650. Figure provided by Søren Nielsen, University of Aarhus, Denmark.