Glucocorticoids (including corticosterone, cortisone, and cortisol) are stress hormones released in the brain in response to stress, fear and anxiety. These stress hormones help response to immediate threat. However, research reports that chronic stress and long-term exposure to stress hormones can increase anxiety and other mood disorders.
The study, published in Behavioral Neuroscience, investigated the effects of corticosterone on mice behavior. Researchers at Harvard Medical School in Boston, administered corticosterone to the drinking water of female Swiss Webster mice, for either 17 or 18 days or for one day. The administration of corticosterone water for 17 or 18 days imitated long-term exposure to stress hormones, and for one day imitated short-term stress. In the first test, mice kept in a dark part of a cage were exposed to a bright, open part of a cage. In the second test, the mice were exposed to a high-frequency sound.
In the first test, researchers found that the mice given corticosterone water for 17 or 18 days were hesitant to emerge into the bright, open space. This behavior was interpreted as anxiety. In the second test, the mice given corticosterone water for 17 or 18 days had a reduced startle reaction to the high-frequency sound. This behavior was interpreted as depression.
"This study suggests that chronic hypercortisolemia may contribute to anxiety-related behavior in patients with Cushing's disease and depression," the study authors conclude. Although the study was conducted with mice, the results may suggest how long-term exposure to stress hormones can increase anxiety and other mood disorders in humans.
REFERENCES:
1. Ardayfio P and Kim KS. Anxiogenic-like effect of chronic corticosterone in the light-dark emergence task in mice. Behav Neurosci 2006 Apr;120(2):249-56.
Posted by Elaine Gavalas on October 12, 2006 03:12 PM
