SUNY Buffalo Study: Constant Stress Linked to Memory Loss

STUDY BY SUNY BUFFALO RESEARCHERS REVEALS WHY CHRONIC STRESS IMPAIRS MEMORY AND MAY TRIGGER MENTAL ILLNESS

hronic stress has a more powerful effect on the brain during adolescence than in adulthood and now there's proof at the molecular level, according to findings published in Neuron by University at Buffalo researchers.

"We have identified a causal link between molecules and behaviors involved in stress responses," says Zhen Yan, PhD, a professor in the Department of Physiology and Biophysics in the UB School of Medicine and Biomedical Sciences. "It's the first time that the loss of glutamate receptor has been causally linked to the negative effects of chronic or repeated stress."

The UB research bolsters the emerging understanding among neuroscientists that the glutamate system is a key player in mental illness and, thus, is critical to understanding how to better treat disorders like depression, anxiety and schizophrenia.

Yan and her colleagues wanted to better understand the molecular mechanisms of stress, about which little is known. She and her colleagues had previously found that acute stress helps sharpen Now they have found that chronic stress has the opposite effect.

The UB research was conducted on male rats at an age that corresponds to adolescence in humans, a period when the brain is highly sensitive to stress. This is especially true of the prefrontal cortex, which doesn't fully mature until age 25 in humans and which undergoes dramatic change during adolescence. The prefrontal cortex is referred to as the "CEO" of the brain, controlling working memory, decision-making and attention.

In response to repeated stress, Yan and her colleagues found there was a loss of glutamate receptor expression and function in the prefrontal cortex. That loss resulted in a significant impairment in the ability of the adolescent animals to remember and recognize objects they had previously seen. The same cognitive deficit was not seen in the similarly stressed adults.

In the same paper, the researchers report that by disrupting the enzymes that trigger loss of glutamate receptor expression, they were able to prevent the cognitive impairment induced by repeated stress exposure. As a result, the UB researchers have discovered that there may be a way to prevent the detrimental effects of chronic stress

The research is especially significant because with some mental disorders, such as schizophrenia, onset typically occurs in late adolescence.

The research was funded by the National Institutes of Mental Health of the NIH.