A control mechanism for intra-mural peri-arterial drainage via astrocytes: How neuronal activity could improve waste clearance from the brain
Fig 3
IPAD inside a cerebral arteriole.
(a) Displacement and stress of the arteriole wall due to U(t) at t = 20 s of a single astrocyte end-foot. Because displacement is fixed to u = 0 at the ends, stresses at the ends are high. Thus, all following results are presented for 10 μm ≤ z ≤ 190 μm. (b) IPAD velocity at various time points over the length of the arteriole wall using K0/K1 = 0.1. The average velocity over time and space is −8.37 μm s−1. (c) IPAD flow rate at various time points over the length of the arteriole wall using K0/K1 = 0.1. The average flow rate over time and space is −7.24 × 10−8 μl/min for a single arteriole. Extrapolated over 6.5 billion arterioles estimated for the human brain it would take 9.92 h to process the total amount of ISF in the brain (280 ml). (d) IPAD velocity for k = 1 × 10−3 (blue), 1 × 10−4 (orange), 1 × 10−5 μm2 (green) over the strength of the valve mechanisms K0/K1. Values are always negative, except at K0/K1 = 1.0. The effect of the valve mechanism is decreased with decreasing k.