Neuroscience 2004 Abstract
| Presentation Number: | 571.11 |
|---|---|
| Abstract Title: | Long-term light deprivation: A new model of depression in rat. |
| Authors: |
Gonzalez, M. M.*1
; Aston-Jones, G.1
1Psychiatry, Lab Neuromod & Behavior, Univ. of Pennsylvania, Philadelphia, PA |
| Primary Theme and Topics |
Neurological and Psychiatric Conditions - Psychiatric Disorders -- Affective disorders--Animal Models |
| Session: |
571. Affective Disorders: Animal Models III Poster |
| Presentation Time: | Monday, October 25, 2004 3:00 PM-4:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # ZZ9 |
| Keywords: | Locus coeruleus, NOREPINEPHRINE, forced swim test, immobility |
Previously we showed that animals maintained in long-term complete darkness (DD) exhibited hypersomnia during the active period and decreased concentration of norepinephrine (NE) as well as fewer fibers/boutons compared to animals maintained under 12:12 light:dark conditions (LD) (Gonzalez and Aston-Jones, SFN Abstr. 2002, 2003). Impairment of the NE-locus coeruleus (LC) system is associated with depression, raising the possibility that DD could induce depression as result of NE-LC dysfunction. Here we tested this hypothesis using a forced swim test (FST) to characterize depressive-like behavioral effects of DD. Adult Sprague Dawley male rats were placed in individual cages with free access to food and water. For six weeks, half of the animals were kept on a 12:12 LD schedule while the rest were kept in DD. Subsequently, at the beginning of the rest period each rat was submitted to a FST under their current lighting conditions. A flotation aid was fitted on the midscapular area and the rat was placed in a tank filled with warm water (29-30°C). Animals were submitted individually to the swim test for 15 min, and 24 h later they were re-tested for 5 min. A depressive state was measured by the time spent being immobile, which was taken as a sign of behavioral despair. These tests revealed that immobility for DD animals was greater than that for LD subjects. This indicates that long-term light deprivation is an environmental factor that may promote depression. Because light deprivation is not stressful for nocturnal animals like the rat, we propose that prolonged DD may provide a non-stressful animal model for depression.
Supported by PHS grant NS24698
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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