Figure 4.

Average TCCs of Gd-DOTA showed occasionally slightly higher CSF Gd-DOTA concentration in the CSF of young (a) and adult (b) hypertensive rats and their normotensive controls. Average TCCs of Gd-DOTA in the brain compartment of young SHR and WKY (c) and adult SHR and WKY (d). Average TCCs are shown as mean ± SD. e, Schematic overview of the one-tissue compartment model applied to brain and CSF TCCs to calculate the glymphatic influx rate (K₁) and efflux rate constant (k₂). f, Example of the one-tissue compartment model fit. The calculated K₁ was significantly lower in the SHR than in WKY in both age groups (g), and k₂ was lower in the adult, but not the young, SHR compared with their age-matched controls (h). Average modeled time-activity curves and residuals from the young (i) and adult (j) age groups. *p < 0.05, **p < 0.01.