Abstract # 42:

Scheduled for Thursday, August 18, 2005 03:30 PM-03:45 PM: Session 6 (Crystal Ballroom) Oral Presentation


NEUROENDOCRINE RESPONSIVITY, MONOAMINE GENOTYPE, AND RESPONSE TO NOVELTY IN ADULT MALE RHESUS MACAQUES

E. L. Kinnally1,2, H. J. Whiteman1, S. P. Mendoza1,2, G. M. Karere2,3, L. A. Lyons3 and J. P. Capitanio1,2
1Department of Psychology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA, 2California National Primate Research Center, 3Population Health and Reproduction, Veterinary Medical School, University of California at Davis
line
     Function of the monoaminergic system has been associated with individual differences in impulsivity. Individual behavioral differences among twenty-four adult rhesus macaques were observed in five situations with differing levels of risk vs. reward, including a novel social challenge. Serotonergic function was measured in two ways: peripheral prolactin response to fenfluramine (a serotonin agonist) reflects the ability of the limbic system to respond to available serotonin. Individual monoamine genotypes (rh5-HTTLPR and rhMAO-LPR) known to impact serotonergic utilization and metabolism were also determined. Individuals with low prolactin response to fenfluramine challenge or low activity alleles of rh5-HTTLPR or rhMAO-LPR were more likely to threaten the observer, (P < 0.05), initiated proximity and aggression toward novel conspecifics more frequently (P = 0.06), exhibited a more rapid initial disengagement with a novel object than other individuals (P < 0.05), and were less likely to be rated as "fearful" in response to a novel object (P < 0.05). Reduced serotonergic function may be associated with risk-taking at multiple levels of reward potential. Further, this effect may be mediated by emotional response to novelty, where high serotonergic function is associated with enhanced fear response to novel stimuli.