Fig. 2

AQP1 is expressed in the brain and peripheral vasculature. a Confocal micrograph from an adult mouse brain (P90) immunolabeled for AQP1 (AQP1ext, magenta and AQP1int, green). DAPI nuclear counterstaining (blue). b AQP1ext⁺ blood vessel, located around the ventricles (delimited by the magenta square in a). c–f Immunoreactive epithelial choroid plexus cells, located in the lateral ventricles, are labeled with both antibodies (high magnification of the area delimited by the green square in a). g, h Micrographs of mouse kidney show the distribution of AQP1 in the vascular endothelium and proximal tubules. i, j Higher magnification image of a blood vessel immunolabeled for CD31 (green) and AQP1int (magenta) (delimited by square in h). Asterisk indicates the lumen of a blood vessel and arrows indicate proximal tubules. k, l AQP1⁺ endothelial cells are also detected in the heart of adult mice. m–o Paraffin sections obtained from adult rat brain show AQP1 immunoreactive blood vessels in the hippocampal fissure and epithelial cells of the choroid plexus located in the third ventricle. Arrows and curved arrowheads indicate arterioles or veins and capillaries or venules, respectively. Straight arrowheads indicate AQP1⁻ blood vessels. 3V, third ventricle; BV, blood vessel; ChP, choroid plexus; DG, dentate gyrus; LV, lateral ventricle; PT, proximal tubule. Scale bars: a, b and g–j 50 µm; c–f 5 µm; k 1 mm; l 100 µm; m 2 mm; n 500 μm; o 200 μm