Daniel Loveland, Brigham Young University
Life Sciences
The monoamine oxidase A (MAOa) gene has been shown to be associated with various social behaviors and disorders such as: aggression, depression, and anxiety (Meyer et al., 2006; Kinnally et al., 2010; Newman et al., 2005); and the MAOa gene interacts with environmental influences to produce its phenotypic effects (Newman et al., 2005; Kinnally et al., 2010). The MAOa gene encodes the enzyme monoamine oxidase A, which is the main enzyme to break down the monoamines into their respective metabolites. An orthologous repeat variant of the MAOa genotype seen in humans has been found in the rhesus macaque: a 5 repeat (R), a 6R and a 7R. This study investigates the influence MAOa genotypes have on central monoamine functioning as measured by cisternal cerebrospinal fluid (CSF) monoamine metabolites associated with behavioral dysfunction (dopamine metabolite: homovanillic acid-HVA, norepinephrine metabolite: 3-methoxy-4-hydroxyphenylgycol-MHPG, and serotonin metabolite: 5-hydroxyindoleacetic acid-5-HIAA). Cisternal CSF was obtained from 136 30-day old infant male rhesus macaques with varying genotypes and rearing backgrounds. We expected to find a rearing by genotype (GxE) effect on the monoamine systems with differences between mother-reared subjects when compared to subjects reared without mothers in peer-only groups. We found significant variability between genotypes; results also showed early rearing modulated this genotypic effect on brain chemistry. This supports our hypothesis that GxE interactions influence monoamine metabolite concentrations, suggesting a possible relationship of GxE interactions on social disorders such as aggression, depression and anxiety.