Cited research: Mol. Psychiatry doi:10.1038/mp.2010.66 (2010)

Stress-related psychiatric disorders such as depression affect more women than men, and researchers have discovered a possible molecular basis for this in rats.

Debra Bangasser at the Children's Hospital of Philadelphia in Pennsylvania and her colleagues put male and female rats through stressful swim tests. They then looked at changes in signalling by the receptor for corticotropin-releasing factor (CRF), which mediates stress responses in the brain. Excessive CRF activity is thought to contribute to depression and post-traumatic stress disorder.

In unstressed females, the team found greater coupling of the receptor to a key protein — an important step in CRF signalling — than in unstressed males. Moreover, female rats' neurons did not internalize these receptors in response to stress — a mechanism for lowering the cells' sensitivity to stress signals — whereas those in males did. These findings, the authors say, are consistent with previous work suggesting that females are more sensitive to low levels of CRF. C.L.