Fig. 4

AQP1 and NKCC1 are present in smooth muscle and endothelial cells of the leptomeningeal vasculature. a, b Paraffin sections of adult mouse brain (P90) immunolabeled with anti-AQP1int or anti-NKCC1 (both brown). c Some sections were stained with hematoxylin (HE, pink) and the vascular identity of blood vessels located in the subarachnoid space (cisterna interpendicularis, delimited by square in a, b) was determined. d, e Consecutive sections show that AQP1int⁺/NKCC1⁺ cells are present in the smooth muscle cell layer of arterioles (arrowheads) and in the endothelium of capillaries and venules, respectively (curved arrowheads). f, g Vascular endothelial cells were labeled by lectin (WGA-FITC, green), followed by standard Immunolabeling. DAPI counterstain (blue) reveal the location of the leptomeningeal vessel (asterisk). h–j Higher magnification confocal images show that AQP1 is restricted to tunica media, where AQP1ext⁺ smooth muscle cells, identified by their round soma (arrowheads) are observed, whereas AQP1 is not present in the endothelial cell layer (curved arrowheads). The arrow indicates a leptomeningeal cell, also AQP1ext⁺. BS, brain stem; Cb, cerebellum; cp, cerebral peduncle; Ctx, cerebral cortex; Hip, hippocampus; Hyp, hypothalamus; OB, olfactory bulb; Pn, pontine nuclei. Scale bars: a, b 2 mm; c–e 100 μm; f–j 50 μm