Comparison of the effects of early handling and early deprivation on maternal care in the rat

It has been reported in the rat that postnatal manipulations can induce robust and persistent effects on off spring neurobiology and behavior; mediated in parr via effects on maternal care. There have, however been few studies of the effects of postnatal manipulations on maternal care. Here, we describe and compare the effects on maternal behavior on postnatal day's 1-12 of two manipulations, early handling (EH, IS-min isolation per day) and early deprivation (ED, 4-hr isolation per day), relative to our normal postnatal husbandry procedure. Maternal behavior was measured at five rime points across the dark phase of the reversed L:D cycle. EH yielded an increase in arched-back nursing across several time points but did not affect any of her behavior ED stimulated a bout of maternal behavior such that licking and arched-back nursing were increased at the rime of dam-litter reunion, although not at any other rime point. Neither EH nor ED affected weaning weight significantly. Importantly, within-treatment variation was high relative to these between-treatment effects. (C) 2001 John Wiley & Sons, Inc.