Abstract # 983 Event # 211:

Scheduled for Saturday, August 20, 2005 10:15 AM-10:30 AM: Session 15 (Parliament Room) Oral Presentation


NEURAL SEROTONIN (5-HT1A) RECEPTOR BINDING POTENTIAL AND DEPRESSION IN ADULT FEMALE CYNOMOLGUS MONKEYS (MACACA FASCICULARIS)

C. Shively1, D. P. Friedman4, H. D. Gage2, M. C. Bounds2, C. Brown-Proctor2, J. B. Blair2, N. Buchheimer2, J. A. Henderson1,3 and M. A. Smith1,3
1Dept. of Pathology (Comparative Medicine), Wake Forest Univ. School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157-1040, USA, 2Radiology, 3Integrative Neuroscience Program, 4Physiology & Pharmacology
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     Using positron emission tomography, we examined 5-HT1a receptor binding availability and its relationship with specific characteristics of depression in 17 adult female cynomolgus monkeys, housed in small social groups of 4 females each. Social behavior was recorded weekly by focal sampling for two years and heart rate was recorded premortem for 24 hrs. Depression was defined as time spent in a slumped /collapsed body posture accompanied by a lack of response to environmental events with open eyes. The distribution of behavioral depression was divided into tertiles. The relationship between behavioral depression and 5-HT1a receptor binding potential (BP) over all brain areas was assessed with a 3 (levels of depression) X 11 (brain areas) ANOVA. Throughout the brain areas examined (raphe, amygdala, hippocampus, anterior cingulate cortex) there was a reduction in 5-HT1a receptor BP in depressed monkeys (P < 0.003). 5-HT1a receptor BP was significantly correlated with aggression and submission in amygdala and hippocampus. Friendly interaction, grooming, and locomotion were significantly correlated with 5-HT1a receptor BP in the left cingulate cortex. 5-HT1a receptor BP was significantly inversely correlated with heart rate in the raphe, left cingulate, and right amygdala. These data suggest that behavioral depression in monkeys is associated with neural serotonergic function. These monkeys may provide a useful model of social-stress induced depression in adult primates. Supported by MH56881, and the MacArthur Foundation.