Study looks at effect of stress on brain

Stress really does mess with your mind. A new study has found that chronic stress can create many of the brain changes associated with mood disorders by blocking a gene called neuritin -- and that boosting the gene's activity can protect the brain from those disorders. The results provide new insight into the mechanisms behind depression, anxiety and bipolar disorder, and could offer researchers a novel target for drugs to treat those conditions.

Ronald Duman, a neurobiologist at Yale University, and colleagues wondered if the poorly understood neuritin might play an important -- and heretofore overlooked -- role in depression and other mood disorders. They induced depression in a group of rats by subjecting them to chronic, unpredictable stress. Depriving them of food and play, isolating them and switching around their day/ night cycles for about three weeks left the rats with little interest in feeding or enjoying a sweetened drink. The rats also gave up and became immobile instead of swimming when placed in a tub of water.

All of the depressed rats showed low levels of neuritin gene activity, and all improved when treated with antidepressants. But boosting their neuritin protein levels helped just as much, the researchers report online Monday in the Proceedings of the National Academy of Sciences. The team found that increasing production of neuritin by injecting the rats with a virus that triggered the gene's expression protected the rats from brain cell atrophy and other structural brain changes seen in mood disorders, even when the rats were exposed to chronic stress.

-- ScienceNOW