A Proposed Animal Model for Investigating Human Depression

FOR IMMEDIATE RELEASE

Contact: Donna Krupa: 703.527.7357Cell: 703.967.2751 or [email protected]

A PROPOSED ANIMAL MODEL FOR INVESTIGATING HUMAN DEPRESSIONResults by Northwestern University researchers suggest the WKY rat could be used to investigate the genetic basis of human depression.

October 11, 2001 - Bethesda, MD--Each month, the American Physiological Society (APS) spotlights recent research findings designed to improve human well being and understand human health. A summary of the peer-reviewed article noted below, which appears in a recent edition of The American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, has such a focus. The Journal is one of 14 peer-reviewed journals comprised of approximately 3,800 articles that are published by the Society each year.

A PROPOSED ANIMAL MODEL FOR INVESTIGATING HUMAN DEPRESSIONResults by Northwestern University researchers suggest the WKY rat could be used to investigate the genetic basis of human depression.

Summary: The Wistar Kyoto (WKY) rat has been shown in several different laboratories to be hyperreactive to stress and to exhibit depressive-like behavior in several standard behavioral tests. Because patients with depressive disorders often exhibit disruptions in the circadian rhythm of activity, as well as altered secretory patterns of the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-thyroid hormones,. Researchers from Northwestern University studied the depressive-like behaviors and sleep abnormalities inherent to the WKY rat in hopes that this strain might be useful as a genetic animal of depression.

Methodology: Researchers Leah C. Solberg, Susan Losee, Olson Fred W. Turek, and Eva Redei tested the hypothesis that the phenomena of altered circadian rhythms and altered secretory patterns occur in the WKY rat. The diurnal secretory patterns of ACTH, corticosterone, and TSH in freely moving WKY rats kept on a long-day cycle were measured and compared to their outbred progenitor strain, the Wistar rat. Plasma levels of T3 at a single time point in these two strains were also measured. In addition, researchers monitored activity rhythms in these strains under both long-day and constant dark conditions.

Results: Plasma ACTH and corticosterone levels remained significantly higher after the diurnal peak for several hours in WKY rats relative to Wistar rats. Plasma levels of thyroid-stimulating hormone were also significantly higher in WKY relative to Wistar rats across a 24-hour period. In addition under constant darkness conditions, WKY rats exhibited a shorter free running period and a decreased response to a phase-delaying light pulse compared with Wistar rats. In several ways, these results are similar to those seen in other animal models of depression as well as in depressed humans, suggesting that the WKY rat could be used to investigate the genetic basis for these abnormalities.

Source: American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, September 2001

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The American Physiological Society (APS) was founded in 1887 to foster basic and applied science, much of it relating to human health. The Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals every year.

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Editor's Note: For the full text of the summary cited above, or to set up an interview with a member of the research team, please contact Donna Krupa at 703.527.7357 (direct dial), 703.967.2751 (cell) or [email protected].