Abstract # 63:

Scheduled for Thursday, June 21, 2007 05:00 PM-07:00 PM: Session 7 (South Main Hall) Poster Presentation

Monoamine oxidase A (MAOA) gene promoter variation interacts with early rearing condition to influence the behavioral response to social separation in rhesus macaques (Macaca mulatta)

M. L. Schwandt1, T. K. Newman2, S. J. Suomi3, J. D. Higley4, M. Heilig1 and C. S. Barr1
1NIH/NIAAA, Laboratory of Clinical and Translational Studies, PO Box 529, Poolesville, MD 20837, USA, 2University of Cape Town, South Africa, 3NIH/NICHD, Laboratory of Comparative Ethology, 4Brigham Young University, Department of Psychology
     Recent studies in humans have found associations between a polymorphism in the monoamine oxidase A (MAOA) promoter region and depression and anxiety disorders. In this study we investigated the effects of MAOA genotype and early rearing experience on the behavioral response to social separation stress in infant rhesus macaques. Six-month old monkeys (n=157; 89 females, 78 males) underwent four consecutive four-day long separations, with each followed by three days of reunion. Peer-reared (PR) monkeys were separated from their peers, while mother-reared (MR) monkeys were separated from their mothers. Behavioral data were collected and subjected to factor analysis and analysis of variance (ANOVA). Genotypes were clustered based on MAOA enzymatic activity (high vs. low). There were significant interactions of rearing and genotype on “depression” (inactivity and self-directed behaviors) in both males [F(1,74)=4.43, p<0.05] and females [F(2,83)=3.00, p=0.05] during the acute phase (day 1) of separation. In both sexes, PR subjects with genotypes corresponding to low enzymatic activity exhibited increased levels of depression relative to PR subjects with high activity genotypes. Additionally, male PR subjects with the high activity genotype exhibited higher levels of “anxiety” (stereotypic behavior) during the acute phase of separation [F(1,74)=3.66, p=0.05]. These data suggest that MAOA genotype interacts with early rearing condition to influence the development of depressive- and anxiety-related behaviors in response to stress.