Summary: Researchers say matcha, a traditional Japanese tea, may help improve mood and mental performance. Matched tea powder activates dopaminergic neural networks and improves depressive symptoms in mice previously stressed by social isolation.
Source: Kumamoto University
Matcha, a traditional Japanese tea, is touted for its health benefits — it can boost mood and mental performance in humans and mice alike — but more mechanistic research is needed. Therefore, researchers from Japan studied the antidepressant effects of matcha tea powder in mice.
The powder activates dopaminergic neural circuits and improves depression in certain mice, depending on the animal’s previous mental state. Further studies like this could help to develop better antidepressants.
Depression is currently the most prevalent mental disorder in the world and the number of people affected by it continues to grow. Although the onset of depression varies from person to person, it is believed that the condition generally results from a reduction in dopamine in the brain.
Dopamine, a neurotransmitter and hormone, plays an important role in elevating mood and keeping a person feeling happy, fulfilled, and motivated.
And although various antidepressants have been developed to counteract the effects of low dopamine, these come with many side effects. In addition, people can develop resistance to antidepressants, which may require higher doses or frequent medication changes over time. These problems gave impetus to the search for natural products with antidepressant effects.
One such product, matcha, has recently gained popularity. Matcha powder is extracted from the leaves of Camellia sinensis, which are rich in mood-boosting compounds, and are traditionally used to make tea.
Consuming this tea has been shown to improve anxiety-like behaviors in mice by activating dopamine function via dopamine D1 receptor signaling. The resulting dopamine boost could also improve symptoms of depression. dr Yuki Kurauchi of Kumamoto University led a research team to study the effects of matcha tea powder on socially isolated mice.
They detailed their findings in an article published in nutrient.
The team used stress-tolerant BALB/c and stress-prone C57BL/6J mice exposed to social isolation stress for their experiments. However, oral administration of a matcha tea suspension appeared to reduce the level of depression in the stress-sensitive mice. This was indicated by their performance in Tail Suspension Tests (TST), commonly used to assess depression in mice.
dr Kurauchi clarifies, “Matcha tea reduced immobility time only in stress-prone mice, which experienced greater stress from social isolation and exhibited greater depression-like behaviors, compared to stress-tolerant mice.”
How did this happen? The team dug deeper. Immunohistochemical analysis of the mouse brain revealed prefrontal cortex (PFC) and nucleus accumbens (NAc) activation in the stress-prone mice after consuming the matcha tea suspension. These regions form an important part of the dopaminergic circuit and are crucial in controlling dopamine levels in the brain.
Their activation – indicated by an increase in the number of cells expressing c-Fos, a key indicator of neuronal activity – would typically increase dopamine levels and elevate mood.
Stress-prone mice with a shorter immobilization time also had more c-Fos-positive cells in the ventral tegmental area (VTA) of their brain (which initiates dopaminergic activity), as well as in PFC and NAc, indicating higher neural dopamine production. In contrast, none of these effects were observed in stress-tolerant mice.
This was further cemented by another finding — administering a dopamine D1 receptor blocker to stress-sensitive mice negated the antidepressant effects of the matcha tea suspension. dr Kurauchi connects everything together.
“These results suggest that matcha tea powder exerts an antidepressant effect by activating the brain’s dopaminergic system, and this is influenced by the mental state of the individual.”
dr Kurauchi is optimistic about the future impact of her research. Now, when evaluating antidepressant medications in individuals, the differences in their mental states should also be considered, considering how sensitively stress-prone mice were to the effects of matcha tea suspension, but stress-tolerant mice were not.
“Also, including matcha in health promotion programs has the potential to enhance its widespread benefits,” he says.
About this news from depression research
Author: press office
Source: Kumamoto University
Contact: Press Office – Kumamoto University
Picture: The image is in the public domain
Original research: Open access.
“The antidepressant effect of matcha tea powder by activating the dopaminergic system in mice is dependent on social isolation stress” by Yuki Kurauchi et al. nutrient
The antidepressant effect of matcha tea powder by activating the dopaminergic system in mice is dependent on social isolation stress
Matcha tea powder is believed to have various physiological benefits; however, its detailed mechanism of action is poorly understood.
Here we investigated whether the mental state of mice due to social isolation stress affects the antidepressant effects of matcha tea powder by using the tail suspension test.
Oral administration of matcha tea powder reduced the duration of immobility in the stress-prone C57BL/6J strain but not in the BALB/c strain. In C57BL/6J mice, SCH23390, a dopamine D1 receptor blocker, prevented matcha tea powder from exerting its antidepressant effects.
Matcha tea powder also increased the number of c-Fos-positive cells in the prefrontal cortex (PFC) region and the nucleus accumbens (NAc) region in C57BL/6J mice but not in BALB/c mice.
In contrast, matcha tea powder did not alter the number of c-Fos positive cells in the ventral tegmental area (VTA) region. Notably, C57BL/6J mice with a shorter immobilization time had higher numbers of c-Fos-positive cells in the PFC, NAc, and VTA regions. However, no such correlation was observed in the stress-tolerant BALB/c mice.
These results suggest that matcha tea powder exerts an antidepressant effect through activation of the dopaminergic system, including the PFC-NAc-VTA circuit, and that mental states are important factors affecting the physiological benefits of matcha tea powder.