Abstract # 165:

Scheduled for Friday, August 19, 2005 07:00 PM-09:00 PM: (Cambridge/Oxford Room) Poster Presentation

Early infant experience, Monoamine Oxidase A (MAOA) genotype and their influence on aggression and ethanol consumption in male rhesus macaques (Macaca mulatta)

N. Davis1, C. S. Barr1, S. J. Suomi2, J. D. Higley1, D. Goldman1 and T. K. Newman1
1National Institue on Alcohol Abuse and Alcoholism, NIH, 5625 Fishers Lane, Room 3S-32, Rockville, MD 20852, USA, 2National Institute on Child Health and Human Development, NIH
     Evidence suggests that decreased MAOA activity is associated with aggressive behavior and increased susceptibility to alcoholism in human males, especially in the context of early childhood stress. We test whether a functional polymorphism in the rhesus MAOA gene influences aggressive behavior and voluntary ethanol consumption in rhesus males, and whether stressful infant experience modulates the effect of genotype. Fifty-three subjects raised by their mothers or in peer-only groups were given access to a sweetened 8.4% ethanol solution during a 7-week test period. In a separate experiment, aggressive behavior was assessed using dyadic food competition and observation of normal social group behavior. Genotypes were grouped according to whether they increased or decreased inferred transcriptional gene activity. Peer-reared males with the high activity allele consumed significantly more ethanol than other males, with a main effect of genotype (P = 0.031) and rearing (P = 0.043), but no interaction effects. Aggressive behavior was influenced by an interaction between genotype and rearing condition (P = 0.028), but with no main effects. Males that consumed more ethanol also exhibited the highest number of fight wounds, and may be engaging in inappropriate forms of aggression that escalates to injurious fights. Aggression expressed during dyadic food competition is ritualized and less likely to result in actual physical contact, and likely falls within the range of normal rhesus behavior.