Scientists find molecular evidence of brain changes in depressed females

Researchers at the University of Pittsburgh School of Medicine have discovered molecular-level changes in the brains of women with major depressive disorder that link two hypotheses of the biological mechanisms that lead to the illness. Their results, published online this week in Molecular Psychiatry, also allowed them to recreate the changes in a mouse model that could enhance future research on depression.

Although women are twice as likely as men to develop depression and have more severe and frequent symptoms, very little research has focused on them or been conducted in other female animals, noted senior author Etienne Sibille, Ph.D., associate professor of psychiatry, Pitt School of Medicine.

"It seemed to us that if there were in the depressed brain, we might be able to better identify them in samples that come from females," he said. "Indeed, our findings give us a better understanding of the biology of this common and often debilitating psychiatric illness."

The researchers examined post-mortem samples of 21 women with depression and 21 similar women without a history of depression. Compared to their counterparts, the depressed women had a pattern of reduced expression of certain genes, including the one for brain-derived neurotrophic factor (BDNF), and of genes that are typically present in particular subtypes of , or neurons, that express the neurotransmitter gamma-aminobutyric acid (GABA.) These findings were observed in the amygdala, which is a brain region that is involved in sensing and expressing emotion.

In the next part of the project, the researchers tested mice engineered to carry different mutations in the BDNF gene to see its impact on the GABA cells. They found two mutations that led to the same deficit in the GABA subtype and that also mirrored other changes seen in the human depressed brain.

Dr. Sibille noted that researchers have long suspected that low levels of BDNF play a role in the development of depression, and that there also is a hypothesis that reduced GABA function is a key factor.

"Our work ties these two concepts together because we first show that BDNF is indeed low in depression and second that low BDNF can influence specific GABA cells in a way that reproduces the biological profile we have observed in the depressed brain," he said.

The team is continuing to explore the molecular pathway between BDNF and GABA and others that could be important in depression.

Provided by University of Pittsburgh

5 /5 (5 votes)

Related Stories

Ketamine helps see how the brain works in clinical depression

Jun 16, 2011

(Medical Xpress) -- In a new study published in Nature, Lisa Monteggia from the University of Texas Southwestern Medical Center looks at how the drug ketamine, typically used as an anesthetic or a popular recreational drug f ...

Secretions of the mind

Feb 25, 2011

A molecule called calcium-dependent activator protein for secretion 2 (CAPS2) promotes the secretion of a neurotrophic factor that is critical for the proper development and survival of networks of interneurons ...

Yoga and elevated brain GABA levels

May 21, 2007

Researchers at Boston University School of Medicine (BUSM) and McLean Hospital have found that practicing yoga may elevate brain gamma-aminobutyric (GABA) levels, the brain's primary inhibitory neurotransmitter. The findings, ...

Marking anorexia with a brain protein

Jun 23, 2009

Eating disorders are frequently seen as psychological or societal diseases, but do they have an underlying biological cause? A new study shows that the levels of a brain protein differ between healthy and anorexic women.

Recommended for you

Mother-daughter research team studies severe-weather phobia

Sep 19, 2014

No one likes severe weather, but for some just the thought of a thunderstorm, tornado, hurricane or blizzard can severely affect their lives. When blood pressures spike, individuals obsessively monitor weather forecasts and ...

Study: Pupil size shows reliability of decisions

Sep 18, 2014

Te precision with which people make decisions can be predicted by measuring pupil size before they are presented with any information about the decision, according to a new study published in PLOS Computational Bi ...

User comments