Dopamine receptor blockade in the nucleus accumbens inhibits maternal retrieval and licking, but enhances nursing behavior in lactating rats

Maternal behaviors were recorded in rats after a 4-h dam-litter separation and intracranial microinfusion of saline on Day 6 postpartum or cis-flupent hixol (FLU), a dopamine (DA) receptor antagonist, on Days 7-9, within the n ucleus accumbens (NA) or dorsomedial striatum (DMS) bilaterally (5, 10, or 20 mu/mu L/side), or the lateral ventricle (LV) unilaterally (20 or 40 mu/m u L). The number of pups retrieved was inhibited in a dosage-dependent mann er by FLU within the NA, bur not in other sites. Pup retrieval did not occu r within 5 min after 20 mu g FLU in five out of nine NA dame; only in these dams did infusions include the shell region of the NA. Duration of pup lic king was dose dependently decreased by FLU, the most within the NA, and to a lesser extent within the DMS. Nursing behavior in the kyphotic (upright, dorsally arched) posture, initiated in the absence of pup retrieval by plac ing the dam over the gathered pups, was not inhibited by intracranial FLU i n any site assessed, but rather lasted longer after FLU in NA dams. These v arious effects of FLU, especially in NA, may be related to modest increases in catalepsy. (C) 1999 Elsevier Science Inc.