Stress signals work differently in the brains of women and men
The highest rates of anxiety and depression occur among women may have a biological basis, according to an animal study by researchers at Children’s Hospital of Philadelphia, USA, published online here in ‘Molecular Psychiatry.
Specifically, they found that stress signals work differently in the brains of women and men, with women being more sensitive to low levels of a hormone that organizes the stress response in mammals – releasing factor corticotropin-releasing factor (CRF, for its acronym in English) and less able to adapt to higher levels than men.
It is known that women have a higher incidence of depression, posttraumatic stress disorder and other anxiety-related problems. However, until now ignored the biological mechanisms underlying that gap with men.
According to the author of this work, Rita J. Valentino, a behavioral neuroscientist at Children’s Hospital of Philadelphia, “this is the first evidence that there is a difference between the sexes in how neurotransmitters and receptor signals exchanged.”
“Although there is more research to determine whether these findings can be applied to humans, it could help explain why women are two times more likely than men to stress-related disorders,” he says.
Valentino’s team examined the brains of a group of rats that responded to a forced swimming test and found that in the brains of rats, the neurons were CRF receptor jumping more power to the cellular signals that male rats, so the response was greater in females with CRF.
Furthermore, after being exposed to stress, male rats showed an adaptive response, called internalization, in their brain cells. Specifically, the cells reduced the number of CRF receptors and thus made less reactive to this hormone. In female rats this adaptation did not occur because a protein important for this internalization is not linked to the CRF receptor.
“This is an animal study and we can not say that the biological mechanism is the same in humans,” Valentino has pointed out, adding that other mechanisms play a role in stress response are humans and that includes action other hormones.
However, he adds, “the researchers already know that the regulation of CRF is disrupted in psychiatric disorders related to stress, so this work could be relevant for understanding human biology.”
In addition, Valentino has stressed that previous studies on stress disorders in animals used only male mice, they remained undetectable gender differences. “The drug works investigating CRF antagonists as a treatment for depression may need to take into account gender differences at the molecular level,” concluded