We are testing the "selfish brain hypothesis" where increases in cerebral vascular resistance trigger systemic neurogenic hypertension.We have shown that increases in cerebral vascular resistance increase sympathetic activity and arterial pressure.However, the transduction mechanism by which reductions in brain blood flow trigger hypertension remain unknown.The transient receptor potential channel 4 (TRPV4) is an attractive mechanism: it has been implicated in detection of shear stress, the resultant arterial vessel re-modelling and has been shown to be essential in the development of pulmonary hypertension, which involved the novel finding of TRPV4 as an oxygen sensor.