CD38 and behavior: moving from correlation to causality?

In this issue, Feldman et al. (1) demonstrate associations between plasma oxytocin (OT) levels and genetic variability in the OT pathway, implying that OT is responsible for parent/infant interactions and confirming its role in bond formation in humans. Further evidence of early social influences on the system is that parental care received during infancy is paralleled by higher levels of plasma OT in adulthood. Neurogenetics suggests that these events are associated with polymorphisms in the oxytocin receptor (OXTR) and CD38 genes (1). Figure 1 shows a schematic representation of the sequence leading from the secretion of OT by hypothalamic neurons to its uptake by OXTR, highlighting the key role played by CD38. Some points are still unexplored. Here we focus on the points grounded in basic science, but conducted in human models.