Fig. 1

Clearance of extracellular solutes is reduced in Aqp4^–/– mice. (A) Schematic diagram illustrating the quantification of extracellular solute clearance from the brain parenchyma. Radioactive tracers (0.18 kDa [³H]mannitol and 500 kDa [³H]dextran) infused into the striatum of anesthetized mice. Whole brains were harvested, homogenized and radioactivity counted by liquid scintillation counting. The percentage clearance was calculated based on total injected radioactivity (R_INJECTED) and the remaining radioactivity in the brain (R_BRAIN). (B) Clearance of intrastriatal 0.18 kDa [³H]mannitol in age-matched Aqp4^–/– and WT mice 1 and 2 h after infusion. n = 10 at 1 h; n = 8 at 2 h per genotype. Average ± SD age: for 1 h – Aqp4^–/– 105 ± 12 days, WT 83 ± 12 days; for 2 h – for Aqp4^–/– 99 ± 14, for WT 91 ± 15. (C) Clearance of intrastriatal 500 kDa [³H]dextran in age-matched Aqp4^–/– and WT mice 2 h after infusion. n = 7 per genotype. Average ± SD age: Aqp4^–/– 105 ± 27 days, WT 104 ± 27 days. Data represented as mean ± s.e.m, ** = p < 0.01, *** = p < 0.001, mixed effects linear regression model (see Materials and Methods)