Predisposition to gastric erosions in the rat: behavioral and nutritional effects of early maternal separation.

After early maternal deprivation (on postnatal day 15), the incidence of restraint-induced gastric erosions on day 30 increases to approximately 5 times that of rats separated at the customary (day 21) weaning age. These data suggest that factors in the mother-infant relationship during postnatal development in young rats can influence later susceptibility or resistance to gastric erosions. We present a series of experiments to test whether loss of behavioral interaction with the mother or loss of maternal milk results in this increase in gastric erosion susceptibility. The results show that the absence of maternal milk, rather than behavioral deprivation, is primarily responsible for the increase in susceptibility after early maternal separation. However, behavioral interaction with the mother can additionally modify this susceptibility.