Impaired maternal behavior in mice lacking norepinephrine and epinephrine

The roles of norepinephrine (NE) and epinephrine in behavior were investigated by targeted disruption of the dopamine beta-hydroxylase (Dbh) gene, thereby eliminating these compounds in vivo. Most heterozygous pups born to Dbh(-/-) females died within several days of birth and were often found scattered within the bedding. Potential causes including deficits in olfaction and lactation were not apparent. A deficit in maternal behavior was confirmed by the lack of pup retrieval exhibited by Dbh(-/-) virgin females. Restoration of NE shortly before but not after birth induced females that previously abandoned their litters to act maternally. Our results suggest that NE is responsible for longlasting changes that promote maternal behavior during both development and parturition in mice.