REARING EXPERIENCE AND BIOGENIC-AMINE ACTIVITY IN INFANT RHESUS-MONKEYS

In this report we present evidence that early social experience influe nces aspects of the function of brain biogenic amine systems most nota bly the noradrenergic system. Biogenic amine activity was studied in m other- vs. peer-reared monkey infants over the first 6 months of life and in response to two housing transitions, Norepinephrine (NE), 3-met hoxy-4-hydroxyphenylglycol (MHPG), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), ann 5-hydroxyindoleacetic acid (5-HLAA) leve ls in cerebrospinal fluid (CSF) were measured Peer-reared monkeys show ed significantly higher CSF levels of norepinephrine and MHPG than mot her-reared animals over early development, but showed an attentuated N E response to separation and group formation compared to mother-reared animals. Peer-reared monkeys showed a greater developmental decline i n 5-HIAA levels than mother-reared monkeys. There were no rearing effe cts for DOPAC or HVA over early development; however, peer-reared monk eys showed significantly lower HVA and DOPAC concentrations at 6-8 mon ths of age, The results add to evidence for the influence of primate m others on the psychobiological development of central nervous system n eurotransmitter systems in their infants, and suggest that the noradre nergic system is among the more sensitive of these to early experience .