Oxytocin, a type of peptide hormone, has been known in the past to promote childbirth and breastfeeding, and in recent years has been confirmed to have the effect of increasing trust in others and improving sociability. It is also known as the “love hormone” and is attracting a lot of attention.

　On the other hand, oxytocin, which is colorless and transparent and has a very small molecular weight, distorts its original behavior when attached with a fluorescent label (tag), which is the usual method of visualization, and makes it impossible to capture its true form.Therefore, despite its popularity, its site of action and dynamics in the brain have been shrouded in mystery.

　In order to realize the first "visualization" of oxytocin, which cannot be seen directly, in this research, we devised a method to bind a very small alkyne tag to oxytocin and developed a new tool "alkyne oxytocin".Since the alkyne tag has little effect on the molecular size of oxytocin, it was confirmed that alkyne oxytocin administered to brain tissue behaves very similarly to in vivo oxytocin.

　Using this, we captured the action sites and spatiotemporal dynamics of oxytocin in living mouse brain tissue.Oxytocin strongly binds to the hippocampus, which controls higher functions of the brain, and oxytocin binds mainly to oxytocin receptors on the surface of cells and then quickly disappears. .

　By clarifying the functions of oxytocin, which had been veiled by this epoch-making method, it is expected that the understanding of oxytocin-related diseases such as autism spectrum disorder and the development of therapeutic drugs will progress. be.Furthermore, it has been found that the "visualization" method of this research can be widely applied to other peptide hormones, and it is expected to greatly advance brain research, which still has many mysteries.

Paper information:[Analytical Chemistry] Probing the Spatiotemporal Dynamics of Oxytocin in Brain Tissue Using a Simple Peptide Alkyne-Tagging Approach