ScienceDaily (Feb. 8, 2008) — Blocking production of a single enzyme alleviates symptoms of depression and anxiety in mice that have low serotonin levels, Duke University Medical Center researchers have found. Serotonin, a chemical that helps brain cells communicate with one another, is the target of the most successful anti-depressant medications. Low levels of serotonin are implicated in depression and many other psychiatric disorders, including increased anxiety, aggression and obsessive-compulsive disorder. The Duke team created mice with a mutation in the gene for tryptophan hydroxylase 2 (Tph2), which helps make serotonin in the brain. An equivalent human mutation has been identified in some people with unipolar major depression. These patients often show resistance to treatment with SSRI antidepressant drugs.
