Dopamine D1 and D2 receptor antagonism in the preoptic area produces different effects on maternal behavior in lactating rats

The preoptic area (POA) is critical for maternal behavior in rats but little is known about what neurotransmitters released here influence maternal responding. POA infusion of 10 jig (but not 2 mu g) of the dopamine D1 receptor antagonist SCH-23390 greatly impaired retrieval and licking of pups but not other maternal or nonmaternal behaviors in lactating rats. In contrast, POA infusion of 10 mu g (but not 2 mu g) of the D2 receptor antagonist raclopride facilitated nursing but did not affect oral maternal behaviors. SCH-23390 in the medial hypothalamus tended to impair licking but not retrieval. Raclopride in the medial hypothalamus had no effects. Therefore, D1 and D2 receptor activity, particularly in the POA, is important for regulating different maternal behaviors.