Background: We describe a successful demonstration that repeated early deprivation of parental care (ED), as used to study effects of early life stress in rats, can be performed in a primate and that it constitutes an early life stressor.
Methods: Seven breeding pairs of marmoset monkeys each provided control twins (CON) and twins that were subjected to ED for 30-120 min/day on postnatal days (PND) 2-28. Urine samples were obtained to monitor the acute effect of ED on cortisol and catecholamine levels. Behavior samples were obtained in the home cage to monitor the effects of ED on infant and infant-parent behavior.
Results: Early deprivation of parental care caused acute increases in cortisol, epinephrine, and norepinephrine. At PND 28, basal cortisol was reduced in ED compared with CON infants, and ED infants were smaller than CON infants. Early deprivation infants tended to spend more time in the suckling position than did CON. Early deprivation infants demonstrated more distress vocalization than CON infants, even though the parental care they received in the home cage was similar. Early deprivation infants tended to play less socially than did CON.
Conclusions: To our knowledge, this is the first demonstration that a repeated early life stressor of the type developed in rats can also be applied to a primate species.