The possibility that one cause of high blood pressure lies within the brain, and not the heart or blood vessels, has been put forward by scientists at the University of Bristol, UK. A research group there found a novel role for a protein called JAM-1, located in the walls of blood vessels in the brain. JAM-1 traps white blood cells, which can then cause inflammation and may obstruct blood flow, resulting in poor oxygen supply to the brain. The article notes that the idea that hypertension is an inflammatory vascular disease of the brain is somewhat controversial.