Quantitative Cellular-Resolution Map of the Oxytocin Receptor in Postnatally Developing Mouse Brains

Oxytocin receptor (OTR) plays critical roles in social behavior development. Despite its significance, brain-wide quantitative understanding of OTR expression remains limited in postnatally developing brains. Here, we validated and utilized fluorescent reporter mice (OTRvenus/+) to examine OTR cells across postnatal periods. We developed postnatal 3D template brains to register whole brain images with cellular resolution to systematically quantify OTR cell densities. We found that cortical regions showed temporally and spatially heterogeneous patterns with transient postnatal OTR expression without cell death. Cortical OTR cells were largely not GABAergic neurons with the exception of cells in layer 6b. Subcortical regions showed similar temporal regulation except the hypothalamus. Moreover, our unbiased approach identified two hypothalamic nuclei with sexually dimorphic OTR expression. Lastly, we created a website to easily share our imaging data. In summary, we provide comprehensive quantitative data to understand postnatal OTR expression in the mouse brain.