Increasing drug dose resulted in a significant increase in CSF outflow at 45 cmH
O ICP. In order to stratify the correlation of the specific drug effects at a steady-state pressure of 45 cmH2O, we plotted drug concentrations against CSF outflow using extrapolated data. (A) saline delivery, (B) noradrenaline (NA) at 50 μM and 500 μM (n = 5), (C) L-NMMA at 10 μM and 100 μM (n = 4), (D) U46619 at 0.1 μM and 1.0 μM (n = 5) and (E) U46619 at 1 mM, 25 cmH2O (n = 3). Asterisk denotes significance relative to no drug treatment (NT) (ANOVA/Dunnett’s test).