Matcha Tea Powder's Antidepressant-like Effect through the Activation of the Dopaminergic System in Mice Is Dependent on Social Isolation Stress

Abstract

Matcha tea powder is believed to have various physiological benefits; however, its detailed mechanism of action has been poorly understood. Here, we investigated whether the mental state of mice, due to social isolation stress, affects the antidepressant-like effect of Matcha tea powder by using the tail suspension test. Oral administration of Matcha tea powder reduced the duration of immobility in the stress-susceptible C57BL/6J strain, but not in BALB/c strain. In C57BL/6J mice, SCH23390, a dopamine D1 receptor blocker, prevented Matcha tea powder from exerting its antidepressant-like effect. 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 change the number of c-Fos-positive cells in the ventral tegmental area (VTA) region. Notably, C57BL/6J mice with a shorter immobility time had a higher number 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-like effect through the 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.

Keywords: BALB/c; C57BL/6J; Matcha; depression; dopaminergic circuit.

Figure 1

Schematic views of the experimental schedules.

Figure 2

Antidepressant-like effects of Matcha tea powder in stress-vulnerable C57BL/6J mice. The immobility time of C57BL/6J and BALB/c mice in the TST were measured. (A,B) The TST was performed 30 min after Matcha tea powder administration (10, 30, and 100 mg/kg, p.o.). (C,D) SCH23390 (50 μg/kg, i.p.) was administered 30 min before the Matcha tea powder administration (100 mg/kg, p.o.). The results are expressed as the means ± SEM. n = 8–10 animals. The data were analyzed by one-way ANOVA followed by Dunnett’s multiple comparisons test. * p < 0.05, ** p < 0.01, *** p < 0.001.

Figure 3

Effects of Matcha tea powder on the neural activity in the VTA region in C57BL/6J and BALB/c mice. (A) A schematic view of the PFC-NAc-VTA circuit (dopaminergic system). Dotted lines in red indicate the area of interest for image analysis of the number of c-Fos-positive cells in the VTA region. (B,E) Representative photographs showing immunohistochemistry on c-Fos in the VTA region 2 h after Matcha tea powder administration (100 mg/kg, p.o.). (C,F) The quantification of the number of c-Fos-positive cells is shown. The results are expressed as the means ± SEM. The data were analyzed by the unpaired t-test. n = 5–6 animals. (D,G) The correlation between immobility time in the TST and the number of c-Fos-positive cells in the VTA region is shown. Scale bars = 100 μm. DA; dopamine, GABA; γ-aminobutyric acid, Glu; glutamate.

Figure 4

Effects of Matcha tea powder on the neural activity in the PFC region in C57BL/6J and BALB/c mice. (A) A schematic view of the PFC-NAc-VTA circuit (dopaminergic system). Dotted lines in red indicate the area of interest for image analysis of the number of c-Fos-positive cells in the PFC region. (B,E) Representative photographs showing immunohistochemistry on c-Fos in the PFC region 2 h after Matcha tea powder administration (100 mg/kg, p.o.). (C,F) The quantification of the number of c-Fos-positive cells is shown. The results are expressed as the means ± SEM. n = 5–6 animals (C) and n = 5 animals (F), respectively. The data were analyzed by the unpaired t-test. * p < 0.05. (D,G) The correlation between immobility time in the TST and the number of c-Fos-positive cells in the PFC region is shown. Scale bars = 100 μm. DA; dopamine, GABA; γ-aminobutyric acid, Glu; glutamate.

Figure 5

Effects of Matcha tea powder on the neural activity in the NAc region in C57BL/6J and BALB/c mice. (A) A schematic view of the PFC-NAc-VTA circuit (dopaminergic system). Dotted lines in red indicate the area of interest for image analysis of the number of c-Fos-positive cells in the NAc region. (B,G) Representative photographs showing immunohistochemistry on c-Fos in the NAc Core and Shell regions 2 h after Matcha tea powder administration (100 mg/kg, p.o.). (C,E,H,J) The quantification of the number of c-Fos-positive cells is shown. The results are expressed as the means ± SEM. n = 4–6 animals. The data were analyzed by the unpaired t-test. * p < 0.05, *** p < 0.001. (D,F,I,K) The correlation between immobility time in the TST and the number of c-Fos-positive cells in the NAc Core (D,I) and Shell (F,K) regions is shown. Scale bars = 100 μm. DA; dopamine, GABA; γ-aminobutyric acid, Glu; glutamate.

Figure 6

Effects of Matcha tea powder on locomotor activity in the open field test in C57BL/6J and BALB/c mice. (A,D) Representative photographs showing the trajectory of the mouse in the open field test for 10 min. The total distance traveled in the open field arena (B,E) and the time spent in the center area (C,F) were measured. The open field test was performed 30 min after the Matcha tea powder administration (100 mg/kg, p.o.). The results are expressed as the means ± SEM. n = 6–7 animals. The data were analyzed by the unpaired t-test.

Figure 7

Matcha tea powder exerts antidepressant-like effect by activating the PFC-NAc-VTA circuit (dopaminergic system) in response to the mental states of mice. The depression state differs in strains of mice subjected to social isolation stress. Matcha tea powder exerts an antidepressant-like effect in C57BL/6J mice. Such effects of Matcha tea powder were not observed in BALB/c mice.