Development of a genetically-encoded oxytocin sensor

Oxytocin (OXT) is a neuropeptide originating in the paraventricular nucleus (PVN) of the hypothalamus, with a role in influencing various social behaviors. However, pinpointing its actions only during the time animals are performing specific behaviors has been difficult to study. Here we developed an optogenetic gene expression system designed to selectively label neuronal populations activated by OXT in the presence of blue-light, named "OXTR-iTango2". The OXTR-iTango2 was capable of inducing gene expression of a reporter gene in both human embryonic kidney (HEK) cells and neurons in a quantitative manner. In vivo expression of OXTR-iTango2 selectively labeled OXT-sensitive neurons in a blue-light dependent manner. Furthermore, we were able to detect a subset of dopamine (DA) neurons in the ventral tegmental area (VTA) that receive OXT activation during social interaction. Thus, we provide a genetically-encoded, scalable optogenetic toolset to target neural circuits activated by OXT in behaving animals with a high temporal resolution.