Chronic stress can contribute to depression, but its effects can be blocked in rats by upregulating a single gene in one brain region.

A gene called neuritin encodes a protein that is involved in the growth of neuronal branches. Hyeon Son and Ronald Duman at Yale University in New Haven, Connecticut, and their team studied the gene at work in a rat model of chronic stress. The researchers found that exposure to stress decreased neuritin expression in a region of the brain called the hippocampus, and that the effect was reversed by an antidepressant. Boosting neuritin protein levels increased the amount of neuronal branching and prevented stress from affecting the animals' behaviour. Silencing the neuritin gene brought on depression-like behaviours.

Chronic stress leads to atrophy of hippocampal neurons, which can increase susceptibility to mood disorders, the authors suggest.

Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1201191109 (2012)