Cannabinoid modulation of mother-infant interaction: is it just about milk?

Mother-infant interactions are essential for proper neurobehavioral development of the offspring, and disruptions in those relationships may result in neuroendocrine, neurochemical and behavioral alterations at adulthood. The neural circuitries involved in mother-infant interactions have not been completely elucidated yet. The brain endocannabinoid system plays an essential role in prenatal and postnatal neurobehavioral development. Here, we will summarize and discuss the available findings about the role of endocannabinoids in three key aspects of mother-infant interactions in rodents: suckling, maternal behavior and separation-induced ultrasonic vocalizations (USVs). The studies reviewed here show that endocannabinoids are not only involved in suckling initiation and, therefore, in the feeding and growth of the offspring, but also regulate the emotional reactivity of rodent pups, as measured by the rate of isolation-induced USVs. Conversely, less information is available about endocannabinoid modulation of maternal behavior, and therefore more research in this direction is warranted. Indeed, since Cannabis sativa preparations are widely used by young people, including pregnant and lactating women, it is important to understand whether developmental exposure to cannabinoids interferes with mother-infant bond formation, potentially leading to neurodevelopmental alterations and increased vulnerability to psychopathology later in life.