Oxytocin (OT), a hypothalamic neuropeptide, plays a crucial role in various animal behaviors. However, real-time in vivo monitoring of brain OT dynamics has been limited. This study introduces MTRIA^OT, a novel G-protein-coupled receptor-based green fluorescent OT sensor with high sensitivity, specificity, and stability. Using viral gene delivery and fiber photometry, MTRIA^OT successfully detected real-time brain OT dynamics in living mice, revealing context-dependent variability influenced by behavioral state and physiological conditions. MTRIA^OT offers a powerful tool for investigating OT dynamics in diverse physiological and pathological processes.

Daisuke Ino, Yudai Tanaka, Hiroshi Hibino, Masaaki Nishiyama