CCK and development of mother preference in sheep: a neonatal time course study

We investigated the effects of a CCK-A receptor antagonist on the developme nt of mother preference. Lambs received 2-NAP either at birth or 6, or 12 h later. Controls were given saline. When tested at 24 h of age, lambs recei ving 2-NAP at birth or 6 h later did not display mother preference unlike c ontrols and lambs which were given 2-NAP at 12 h. The effect of the antagon ist persisted at 48 h of age in lambs treated at birth. This suggests that endogenous CCK participates in the development of mother preference only in the first few hours following birth. (C) 2001 Elsevier Science Inc. All ri ghts reserved.