Hypoxemia, oxygen content, and the regulation of cerebral blood flow

This review highlights the influence of oxygen (O 2 ) availability on cerebral blood flow (CBF). Evidence for reductions in O 2 content (Ca O 2 ) rather than arterial O 2 tension (Pa O 2 ) as the chief regulator of cerebral vasodilation, with deoxyhemoglobin as the primary O 2 sensor and upstream response effector, is discussed. We review in vitro and in vivo data to summarize the molecular mechanisms underpinning CBF responses during changes in...