Stress hormone impacts memory, learning in diabetic rodents

February 17, 2008

Diabetes is known to impair the cognitive health of people, but now scientists have identified one potential mechanism underlying these learning and memory problems. A new National Institutes of Health (NIH) study in diabetic rodents finds that increased levels of a stress hormone produced by the adrenal gland disrupt the healthy functioning of the hippocampus, the region of the brain responsible for learning and short-term memory. Moreover, when levels of the adrenal glucocorticoid hormone corticosterone (also known as cortisol in humans) are returned to normal, the hippocampus recovers its ability to build new cells and regains the “plasticity” needed to compensate for injury and disease and adjust to change.

The study appears in the Feb. 17, 2008, issue of Nature Neuroscience and was conducted by the National Institute on Aging (NIA), part of the NIH. NIA’s Mark Mattson, Ph.D., and colleagues in the Institute’s Intramural Research Program performed the study with Alexis M. Stranahan, a graduate student at Princeton University in New Jersey.

“This research in animal models is intriguing, suggesting the possibility of novel approaches in preventing and treating cognitive impairment by maintaining normal levels of glucocorticoid,” said Richard J. Hodes, M.D., NIA director. “Further study will provide a better understanding of the often complex interplay between the nervous system, hormones and cognitive health.”

Cortisol production is controlled by the hypothalamic-pituitary axis (HPA), a hormone-producing system involving the hypothalamus and pituitary gland in the brain and the adrenal gland located near the kidney. People with poorly controlled diabetes often have an overactive HPA axis and excessive cortisol produced by the adrenal gland. To study the interaction between elevated stress hormones and the hippocampal function, researchers tested the cognitive abilities and examined the brain tissue in animal models of rats with Type 1 diabetes (insulin deficient) and mice with Type 2 diabetes (insulin resistant).

Researchers found that diabetic animals in both models exhibited learning and memory deficits when cortisol levels were elevated due to impaired plasticity and declines in new cell growth. Returning the levels to normal, however, reversed the negative impact on the hippocampus and restored learning and memory.

“This advance in our understanding of the physiological changes caused by excessive production of cortisol may eventually play a role in preventing and treating cognitive decline in diabetes,” said Mattson, who heads the NIA’s Laboratory of Neurosciences. He and Stranahan explained these findings may also help explain the connection between stress-related mood disorders and diabetes found in human population studies.

Source: National Institute on Aging

Explore further: Early supplementation may help offset early-life stress on the adult brain

Related Stories

The current state of psychobiotics

October 25, 2016

Now that we know that gut bacteria can speak to the brain—in ways that affect our mood, our appetite, and even our circadian rhythms—the next challenge for scientists is to control this communication. The science of psychobiotics, ...

Imaging technique maps serotonin activity in living brains

October 20, 2016

Serotonin is a neurotransmitter that's partly responsible for feelings of happiness and for mood regulation in humans. This makes it a common target for antidepressants, which block serotonin from being reabsorbed by neurons ...

Going for a run could improve cramming for exams

October 19, 2016

Ever worried that all the information you've crammed in during a study session might not stay in your memory? The answer might be going for a run, according to a new study published in Cognitive Systems Research.

Recommended for you

Natural compound reduces signs of aging in healthy mice

October 27, 2016

Much of human health hinges on how well the body manufactures and uses energy. For reasons that remain unclear, cells' ability to produce energy declines with age, prompting scientists to suspect that the steady loss of efficiency ...

A metabolic switch to turn off obesity

October 27, 2016

You've tried all the diets. No matter: you've still regained the weight you lost, even though you ate well and you exercised regularly! This may be due to a particular enzyme in the brain: the alpha/beta hydrolase domain-6 ...

Mitochondria control stem cell fate

October 27, 2016

What happens in intestinal epithelial cells during a chronic illness? Basic research conducted at the Chair of Nutrition and Immunology at the Technical University of Munich (TUM) addressed this question by generating a new ...

Scientists develop 'world-first' 3-D mammary gland model

October 27, 2016

A team of researchers from Cardiff University and Monash Biomedicine Discovery Institute has succeeded in creating a three-dimensional mammary gland model that will pave the way for a better understanding of the mechanisms ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.