Maternal absence and stability of individual differences in CSF 5-HIAA concentrations in rhesus monkey infants.
OBJECTIVE
Early life events often lead to deficits in CNS serotonin function, which underlie a number of reoccurring psychopathological disorders. Studies using rhesus macaques have demonstrated that early maternal deprivation reduces CNS serotonin turnover, as measured by cisternal CSF 5-HIAA concentrations. In addition, individual differences in CSF 5-HIAA remain stable from the first year of life through adulthood. The purpose of this study was to assess 1) the impact of rearing environment on the early development (<6 months of age) of the serotonin system, and 2) at what stage of early development individual differences in CSF 5-HIAA concentrations stabilize.


METHODS
The subjects were 256 infant rhesus macaques reared in three different conditions (mother-reared, peer-reared, and surrogate/peer-reared). Cisternal CSF was obtained at 14, 30, 60, 90, 120, and 150 days of age.


RESULTS
No differences in CSF 5-HIAA concentrations were observed between peer only- and surrogate/peer-reared infants, and these groups combined exhibited lower 5-HIAA concentrations than mother-reared infants throughout early development. CSF 5-HIAA concentrations declined with increasing age regardless of rearing condition. Within each rearing condition, individual differences in CSF 5-HIAA concentrations remained stable from 14 to 150 days of age.


CONCLUSIONS
Early maternal deprivation reduces CNS serotonin turnover, and individual differences in CSF 5-HIAA concentrations are trait-like and appear to stabilize in infancy.
Shannon
Courtney
C
NIH Animal Center, Building 112, P.O. Box 529, Poolesville, MD 20837-0529, USA.
Schwandt
Melanie L
ML
Champoux
Maribeth
M
Shoaf
Susan E
SE
Suomi
Stephen J
SJ
Linnoila
Markku
M
Higley
James D
JD
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal / Q000502:physiology; D015415:Biomarkers; D007174:Disruptive, Impulse Control, and Conduct Disorders / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid* / Q000378:metabolism; D007206:Individuality; D008253:Macaca mulatta / Q000134:cerebrospinal fluid* / Q000254:growth & development; D008297:Male; D008426:Maternal Deprivation; D023421:Models, Animal; D019964:Mood Disorders / Q000209:etiology / Q000503:physiopathology; D012701:Serotonin / Q000378:metabolism / Q000502:physiology; D012919:Social Behavior; D012931:Social Environment; D013315:Stress, Psychological / Q000134:cerebrospinal fluid / Q000378:metabolism
D015415:Biomarkers; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid