Abnormal maternal behavior in mice lacking phospholipase Cβ1

Abstract

Motherhood goes through preparation, onset and maintenance phases until the natural weaning. A variety of changes in hormonal/neurohormonal systems and brain circuits are involved in the maternal behavior. Hormones, neuropeptides, and neurotransmitters involved in maternal behavior act via G-protein-coupled receptors, many of which in turn activate plasma membrane enzymes including phospholipase C (PLC) beta isoforms. In this study, we examined the effect of PLC beta 1 knockout (KO) on maternal behavior. There was little difference between PLC beta 1-KO and wild-type (WT) dams in the relative time spent in maternal behavior during the period between 24 h prepartum and 12 h postpartum (-24 h similar to PPH 12). After PPH 18, however, PLC beta 1-KO dams neglected their pups so that they all died in 2-3 days. In the pup retrieval test, latency was not different during the period within PPH 12, but after PPH 18, PLC beta 1-KO dams could not finish pup retrieval in a given time. During both periods, FosB expression in the nucleus accumbens (NAcc) of PLC beta 1-KO dams was significantly lower than WT, but not different in the medial preoptic area (mPOA). Given that mPOA activity is required for initiation of maternal behavior, and that NAcc is known to be involved in maternal motivation and maintenance of maternal behavior, our results suggest that PLC beta 1 signaling is essential for transition from the onset to maintenance phase of maternal behavior.