A Blood Pressure Hormone Implicated in Psychosis In an effort to find a marker that predicts psychosis, postdoctoral researcher Lindsay Hayes, Ph.D., learned unexpectedly that mice and people with behavior disorders have abnormally low levels of a hormone system tied to blood pressure regulation and inflammation. In the cerebrospinal fluid of patients with first episode psychosis, she noticed abnormally low levels of the enzyme that makes the hormone angiotensin. To see if these results correlated to animals and could be studied in the lab, Hayes, who works in the laboratory of Akira Sawa, M.D., Ph.D., treated brain cells with angiotensin and inflammation activators in their mouse model for behavior disorders, then measured the output of proteins involved in inflammation. Compared to normal mice, the cells from the mouse with behavioral disorders released more inflammation protein when treated with low levels of angiotensin and less when treated with high levels. Next, she looked at gene expression levels of the angiotensin system components in the brain cells of the behavioral disorder mice. The gene expression levels for the receptor that detects angiotensin were abnormally low in a specific type of brain cell. Hayes says these specific cells in the behavior disorder mice seem to be less susceptible to angiotensin’s immunosuppressive properties, because they have less receptor to detect angiotensin than the same brain cells in normal mice. Hayes and Sawa plan to investigate whether targeting angiotensin could control inflammation and perhaps treat psychosis.