Abstract # 991 Event # 209:

Scheduled for Saturday, August 20, 2005 09:30 AM-09:45 AM: Session 15 (Parliament Room) Oral Presentation

Effects of serotonin transporter (5-HTT) gene variation and maternal maltreatment on behavior and hypothalamic pituitary adrenal (HPA) axis activity in rhesus monkeys (Macaca mulatta)

K. McCormack1,2, T. K. Newman3, D. Maestripieri2,4, J. D. Higley3 and M. M. Sanchez1,2
1Emory University, Dept. of Psychiatry and Behavioral Sciences, Atlanta, GA, 2Yerkes National Primate Research Center, 3Lab of Neurogenetics, NIAA, NIH, 4Institute for Mind and Biology, University of Chicago
     A functional polymorphism in the serotonin transporter gene promoter (5-HTTLPR) is associated with variations in behavior and HPA axis function. Because 5-HTTLPR genotype (l/l, l/s, s/s) influences the behavioral and physiological effects of adverse rearing, we studied the effects of 5-HTTLPR variation and maternal maltreatment in 10 abusive and 10 non-abusive mother-infant pairs. Mother-infant pairs were focally observed every week at the Yerkes Primate Center. Reactivity ratings (adapted from Brazelton) were also collected. Resting cortisol levels were measured monthly, as well as behavioral, ACTH, and cortisol responses to maternal separations. All analyses were run with repeated measures ANOVA and the accepted level of significance was P < 0.05. Infants with the l/s genotype demonstrated deviations in social play, and higher rates of anxiety. In response to stress, l/s infants were more behaviorally reactive, and mounted a larger cortisol response than l/l infants. Similarly, l/s mothers mounted a larger cortisol response to separation from their infants. There were also complex rearing by genotype interactions. Abused infants with the l/s genotype demonstrated higher levels of resting cortisol during month 1, when abuse rates were highest, compared to the other groups, but consistently lower levels of cortisol after month one. These results suggest that the short 5-HTT allele is associated with increased behavioral and physiological reactivity to stress, and that genotype may also modulate the effects of maltreatment during development. Support: NIMH grants MH01005 (MMS), MH62577 (DM), GM00680 (KM), & RR-00165.