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Oxytocin: "Love hormone" can also increase aggression


Study: Oxytocin can lead to aggression

It has long been known that the hormone oxytocin can increase positive feelings. But apparently the so-called “love hormone” can also trigger aggression. Researchers now come to this conclusion. Their results could shed new light on oxytocin treatment for various psychiatric disorders from social anxiety and autism to schizophrenia.

Oxytocin is a hormone that regulates many important physiological functions in humans, such as reproduction, cardiovascular, social behavior and learning. It is also known as the "love hormone" and regulates processes such as the mother-child bond and is also responsible for initiating birth and breastfeeding. And it can lead to aggression, according to a new study.

Limitations during the corona pandemic

As the Max Planck Institute for Psychiatry writes in a recent announcement, couples were forced to spend days and weeks together during the pandemic restrictions - some of them have found their love again, while others are probably on their way to becoming a divorce judge.

Oxytocin, a peptide that is produced in the brain, may have played a role in this: it is known that, as a neuromodulator, it can increase positive feelings.

What is new is that it can also trigger aggression. This is the conclusion drawn by scientists at the Weizmann Institute for Science. Together with researchers from the Max Planck Institute for Psychiatry in Munich, they manipulated and examined the oxytocin-producing brain cells of mice that live in semi-natural conditions.

The study results were published in the journal "Neuron".

Worked on the study for eight years

According to the experts, a lot of knowledge about the effects of neuromodulators such as oxytocin comes from behavioral studies on laboratory animals under standard laboratory conditions: all parameters are strictly controlled and artificial.

However, a number of recent scientific studies suggest that the actions of a mouse in a semi-natural environment tell a lot more about its natural behavior, especially if the findings are to be applied to humans.

The research team led by neurobiologist Alon Chen has created an experimental setup that makes it possible to observe mice in an environment that is more similar to their natural living conditions.

The scientists worked on the study for eight years: day and night, the researchers monitored the activity of the rodents with cameras and analyzed them using a computer.

What was new in particular was the use of optogenetics and a specially developed implantable device that made it possible to switch certain nerve cells in the brain remotely on or off with the help of light. This enabled the researchers to track the behavior of the mice in a natural environment while analyzing their brain functions.

Oxytocin served as a kind of test run for the experimental system. The so-called “love hormone” has long been suspected not only of conveying positive feelings, but rather of reinforcing the perception of social signals and thus, depending on the individual character and the environment, also favoring socially conspicuous behavior.

The team used mice for the study, in which they were able to gently activate the oxytocin-producing cells in the hypothalamus.

"Love hormone" rather a "social hormone"

The mice initially showed an increased interest in one another in the semi-natural environment, but increasingly aggressive behavior was added. In contrast, the increasing oxytocin production in animals led to reduced aggression under classic laboratory conditions.

As the communication goes on to say, aggressive behavior could be expected in a purely male, natural social environment if the animals compete for territory or food. This means that the social conditions are conducive to competition and aggression.

A different social situation, such as the standard laboratory conditions, however, leads to a different effect of the oxytocin.

So if the “love hormone” is more of a “social hormone”, what does that mean for its pharmaceutical use? According to the experts, its effects depend on both the context and the personality. This implies that a much more nuanced view is required for therapeutic use.

According to the researchers, the complexity of behavior can only be understood by studying it in a complex environment. Only then can knowledge be transferred to human behavior. (ad)

Author and source information

This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.

Swell:

  • Max Planck Institute for Psychiatry: "Love hormone" Oxytocin can also increase aggression, (accessed: June 17, 2020), Max Planck Institute for Psychiatry
  • Sergey Anpilov, Yair Shemesh, Noa Eren, Hala Harony-Nicolas, Asaf Benjamin, Julien Dine, Vinıcius E.M. Oliveira, Oren Forkosh, Stoyo Karamihalev, Rosa-Eva Hüttl, Noa Feldman, Ryan Berger, Avi Dagan, Gal Chen, Inga D. Neumann, Shlomo Wagner, Ofer Yizhar, Alon Chen: Wireless Optogenetic Stimulation of Oxytocin Neurons in a Semi-natural Setup Dynamically Elevates Both Pro-social and Agonistic Behaviors; in: Neuron, (access: June 17, 2020), Neuron


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