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Cyclical corticosterone administration sensitizes depression-like behavior in rats
Katherina A Lebedeva1, Hector J Caruncho2, Lisa E Kalynchuk3
1Department of Psychology, University of Saskatchewan, Saskatoon, SK, Canada.
Neuroscience Letters
|April 18, 2017
Summary
Repeated corticosterone (CORT) exposure in rats worsened depression-like behaviors and reduced recovery between cycles. This model better reflects human depression
Area of Science:
- Neuroscience
- Behavioral Science
- Endocrinology
Background:
- Chronic stress is a key risk factor for depression.
- Current animal models often fail to capture the cyclical nature of human depression.
Purpose of the Study:
- To investigate if repeated cycles of corticosterone (CORT) exposure sensitize depression-like behavior in rats.
- To develop an animal model that better reflects the episodic recurrence seen in human depression.
Main Methods:
- Rats received two 21-day cycles of CORT (20 or 40mg/kg) or vehicle, with intervening recovery periods.
- Depression-like behavior was assessed using repeated forced swim tests (FSTs) throughout the study.
- Body weight and potential effects of repetitive testing were considered.
Main Results:
- CORT administration across two cycles led to progressively intensified depression-like behaviors.
- Recovery between CORT exposure cycles was significantly reduced.
- The effects suggest a sensitization of depression-like behavior with repeated stressor exposure.
Conclusions:
- Repeated CORT exposure provides a more valid animal model for studying recurrent depression.
- This model may help elucidate mechanisms underlying mood cycling in depression.
- Understanding episode recurrence is crucial as it affects over 70% of patients.