Abstract # 77:

Scheduled for Friday, June 20, 2008 03:30 PM-03:40 PM: Session 8 (Meeting Room 1GHI) Oral Presentation

Serotonin Transporter Expression is Predicted by Maternal Aggression and is Associated with Disinhibited Behavior in Infant Rhesus Macaques (Macaca mulatta)

E. L. Kinnally1, E. Tarara2, W. A. Mason2, K. Abel2, S. P. Mendoza2 and J. P. Capitanio2,3
1Columbia University/New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10025, USA, 2California National Primate Research Center, 3Department of Psychology, University of California, Davis
     Early experience has been shown to modify genomic function, with long-term consequences for behavior. In the present study, we investigated the impact of natural variation in mother-infant interactions on serotonin transporter (5-HTT) expression and behavioral response to maternal separation in infant rhesus macaques. We observed 54 rhesus macaque mother-infant pairs living outdoors in large social groups (40-130 members) three times per week for postpartum weeks 1-12. All instances of maternal aggression, as well as infant social behavior, were recorded. Infants were separated from mothers for a standardized 25-hour biobehavioral assessment at week 12. During this assessment, infant activity levels and interaction with a novel object was observed. 5-HTT expression was quantified from peripheral blood mononuclear cells sampled during the assessment, approximately 7 hours after maternal separation. Pearson correlations show 5-HTT expression was lower in infants with more aggressive mothers [r(52)=-0.29, p<0.05]. Further, low 5-HTT expression, but not maternal aggression, predicted behavioral disinhibition, as infants with lower 5-HTT had more social partners in their natal groups during the first three months of life [r(52)=-0.35, p<0.05], more frequent interactions with a novel object during assessment [r(52)=-0.37, p<0.05] and tended to be more active [r(52)=-0.25, p=0.07] than other infants. We conclude that 5-HTT regulation may be an important mediator between early experience and behavioral development.