Inhibition of aquaporin-4 significantly increases regional cerebral blood flow
… control system. Oxygen saturation (SpO 2 ) was monitored throughout the study
procedure using a pulse oximeter, Mouse Ox (STARR Life Sciences Co., Oakmont,
Pennsylvania, USA), with probe placement on the left thigh. The … The effects of the aquaporin-4 (AQP-4) inhibitor TGN-020 on regional cerebral blood flow (rCBF) was examined in wild-type (WT) and AQP-4 knockout (KO) mice in vivo. Although baseline absolute rCBF of WT and KO mice were equivalent (158.9±17.7 and 155.5±10.4 ml/100 g/min, respectively), TGN-020 produced a significant increase in rCBF compared with saline-treated WT mice (control), reaching a plateau 20 min after administration (118.45±8.13%, P<0.01). TGN-020 showed no effect on KO mice, supporting the concept that the observed increase in rCBF in WT mice was AQP-4 dependent. Administration of acetazolamide (positive control) produced an even greater increase in rCBF in WT compared with TGN-020 and a similar response in KO mice as well, reaching a sustained plateau 5 min after administration (138.50±9.75 and 138.52±9.76%, respectively, P<0.01 compared with baseline or saline-treated control mice). The study demonstrated that AQP-4 plays a role in regulation of rCBF.