Light on oxytocin, the happy hormone

Summary: A newly developed fluorescent sensor is able to detect oxytocin in live animals.

Source: Osaka University

Twinkling lights make the view of the city even more beautiful at night and can evoke feelings of romance and happiness. But what do these feelings look like inside the brain?

Recently, researchers in Japan showed that the power of light can also be harnessed to control the release of oxytocin (OT), a peptide produced in the brain that is associated with feelings of happiness and love.

In a new study published in Methods of nature, researchers led by Osaka University reported their development of a novel fluorescent sensor for OT detection in living animals. OT plays an important role in a variety of physiological processes, including emotion, appetite, parturition, and aging.

Impaired OT signaling is thought to be associated with neurological disorders such as autism and schizophrenia, and a better understanding of OT dynamics in the brain may provide insight into these disorders and contribute to possible ways of treatment

Previous methods for detecting and monitoring OT have been limited in their ability to accurately reflect dynamic changes in extracellular OT levels over time. Thus, the research team led by Osaka University sought to create an efficient tool to visualize the release of OT in the brain.

“Using the medaka fish oxytocin receptor as a scaffold, we designed a highly specific and ultrasensitive green fluorescent OT sensor called MTRIAOT” says the study’s lead author, Daisuke Ino.

“Binding of extracellular OT leads to an increase in MTRIA fluorescence intensityOTwhich allows us to monitor extracellular levels of OT in real time.”

The research team performed cell culture assays to examine the performance of MTRIAOT. Subsequent application of MTRIAOT in the brain of living animals allowed the successful measurement of OT dynamics using fluorescence recording techniques.

OT plays an important role in a variety of physiological processes, including emotion, appetite, parturition, and aging. The image is in the public domain

“We examined the effects of potential factors that may affect OT dynamics, such as social interaction, anesthesia, feeding, and aging,” says Ino.

The research team’s analyzes revealed variability in OT dynamics in the brain that depended on the animals’ physical and behavioral conditions. Interactions with other animals, exposure to anesthesia, food deprivation, and aging corresponded with specific patterns of brain OT levels.

These findings indicate that MTRIAOT may serve as a useful tool to improve our understanding of OT dynamics in the brain. As abnormalities in OT signaling are believed to be associated with mental disorders, this tool may pave the way for the development of new therapeutics for the treatment of these diseases.

In addition, the researchers found that the MTRIA backbone used to design the OT sensor can also serve as a scaffold to create sensors for other important brain hormones and neurotransmitters.

About this oxytocin research news

Author: Press Office
Source: Osaka University
Contact: Press Office – Osaka University
Image: The image is in the public domain

Original Research: Open access
“A fluorescent sensor for real-time measurement of extracellular oxytocin dynamics in the brain” by Daisuke Ino et al. Methods of nature

See also

This shows data from the study


A fluorescent sensor for real-time measurement of extracellular oxytocin dynamics in the brain

Oxytocin (OT), a hypothalamic neuropeptide that acts as a neuromodulator in the brain, orchestrates a variety of animal behaviors.

However, the relationship between OT brain dynamics and complex animal behaviors remains largely elusive, partly due to the lack of a suitable technique for real-time recording in vivo.

Here, we describe MTRIAOTa green fluorescent OT sensor based on G protein-coupled receptors that has a large dynamic range, suitable affinity, ligand specificity for OT orthologs, minimal effects on downstream signaling, and long-term fluorescence stability.

By combining viral gene delivery and fiber photometry-mediated fluorescence measurements, we demonstrate the utility of MTRIAOT for real-time detection of brain OT dynamics in living mice.

MTRIAOT-The averaged measurements indicate variability of the dynamics of the OT depending on the behavioral context and the physical condition of an animal. MTRIAOT will likely enable the analysis of OT dynamics in a variety of physiological and pathological processes.

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