Strain of Mother Determines Long-Term Effects of Early Handling: Evidence for Maternal Mediation

Inbred A/J mice were raised from birth by foster mothers of either the A/J or C57B1/6J strain. Some litters of each maternal rearing condition were handled during the preweaning period, whereas others were not. In adulthood, the behavior of females in the open field as well as the plasma corticosterone levels of males following both no disturbance and placement in a novel environment were examined. Defecation in the open field was found to be greater in handled than in nonhandled subjects, but only for those that had been reared by a C57B1/6J foster mother. Conversely, plasma corticosterone levels were observed to be lower in handled than in nonhandled subjects, but only for those reared by an A/J foster mother. These results provide support for the hypothesis of maternal mediation of long-term effects of differential early stimulation. (39 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved