Stress can really mess with your brain. A new study finds that chronic stress creates many of the brain changes associated with mood abnormalities by blocking a gene called neuritin, and that boosting the gene’s activity usually protects the brain from those disruptions. The findings identify mechanisms in organisms that lead to frustration, anxiety, and manic depression, and provide a new means of finding medications to treat these symptoms. Research has shown that emotional abnormalities can have many negative effects on people’s brains and lives. Autopsies and brain scans have shown that the hippocampus (the brain’s memory center) produces a certain amount of shrinkage and atrophy in people with mood abnormalities or a history of depression. People with abnormal moods usually have a low level of brain-derived neurotrophic factor (BDNF, a growth factor that keeps neurons healthy), and they also have low activity of the neurotrophin gene, which encodes the protein with the same name responsible for protecting brain plasticity. Neurobiologist Ronald Duman of Yale University in the United States. Ronald Duman, a neurobiologist at Yale University in the US, and his colleagues wanted to know whether neuregulin played an important role in emotional abnormalities and its role in depression or other mental illnesses. The researchers induced symptoms of depression in rats by subjecting them to chronic, indeterminate stress. For three weeks, the researchers deprived them of food and play, isolated them, and disrupted their biological clocks until the rats lost interest in eating or even dessert. The rats also gave up swimming and didn’t move in a tub full of water (this is a way to detect if a rodent is depressed). All of the rats that showed depression had low activity in the gene for neurotransmitter protein, but levels of neurotransmitter protein rebounded after they were given antidepressant medication. The study was published June 25 in the Proceedings of the National Academy of Sciences (PNAS). The team also found that injecting rats with a certain virus that triggers the expression of the neurotransmitter protein gene increased neurotransmitter protein levels even when the mice were under chronic stress, preventing brain cells from shrinking and other brain tissues from producing changes. “Neurosynuclein produces effects like antidepressants,” said Duman, “and I was surprised to find that the molecule itself could block the effects of stress and depression.” To further understand the role of neuregulin, the researchers inhibited the gene’s activity in another group of mice but did not apply external stress, and as a result, the rodents exhibited the same depressive symptoms as the previous group. “The results of the experiment add some more evidence that stress promotes mood abnormalities and also suggests that mimicking the action of neuronal synaptic proteins is another way to treat depression.” John Neumayer, a psychiatrist and neurologist at the University of Washington who was not involved in the study. John Neumaier said, “This is a great study that analyzes depression and antidepressant drugs on a biological level and provides a new idea for treating depression.” Currently only about 30% of people with abnormal moods are effectively relieved by the use of existing antidepressant medications, “but there are problems in applying some of the new findings to new clinical medications, and if someone is willing to take the risk and has the financial means to do so, neuromodulin would be a great way to go.”