Abstract # 131:

Scheduled for Friday, August 18, 2006 04:50 PM-05:10 PM: Session 13 (Regency East #1) Oral Presentation

The role of genetic polymorphisms in understanding the behavioral and hypothalamic-pituitary-adrenal (HPA) axis responses of abused and non-abused rhesus monkeys (Macaca mulatta) to novel stimuli

K. McCormack1,2, A. P. Grand2,3, T. K. Newman4, D. Maestripieri2,5, J. D. Higley4 and M. M. Sanchez2,6
1Spelman College, 350 Spelman Lane, Box 209, Atlanta, GA 30314, USA, 2Yerkes National Primate Research Center, Emory Univ, 3University of Georgia, 4Lab of Neurogenetics, NIAAA, NIH, 5University of Chicago, 6Dept of Psychiatry & Behavioral Sciences, Emory Univ
     Genetic polymorphisms in the serotonin transporter (SERT) gene have been associated with behavioral and HPA axis alterations. Previously, we reported that rhesus macaque infants with the long/short genotype (l/s) exhibited alterations in social behavior, and were more behaviorally and physiologically reactive than infants with the long/long genotype (l/l). In addition, SERT gene variation also affected developmental outcomes of infant abuse. Infant abuse was defined as the mother dragging, crushing, throwing, stepping or sitting on, or rough grooming her infant. We now review the effects of SERT genotype on the responses to novel stimuli. We used three paradigms that evoke emotional and physiological responses in monkeys: 1) Human Intruder (HI), and 2) Approach/Avoidance tasks using exposure to either neutral or 3) fear-evoking objects. Ten abused macaques and ten matched controls were exposed to these stimuli when they were 24 months old, during three separate sessions. Following each test, blood samples were collected. All data were analyzed with RM-ANOVA’s, using p<0.05. In response to all of the objects, l/l infants explored the objects more (e.g., manipulation, biting) than did the l/s infants. However, in response to the HI, l/l infants spent more time avoiding the intruder, whereas l/s infants spent more time exploring. Although abuse affected the responses to these tests, we did not find genotype x rearing history effects in these novel paradigms, nor did we detect effects on HPA activity. These findings suggest that the influence of genetic polymorphisms on behavioral responses is context specific, as has been previously proposed.