Effect of Yokukansan and Yokukansankachimpihange on Aggressive Behavior, 5-HT Receptors and Arginine Vasopressin Expression in Social Isolation-Reared Mice

Sansoninto attenuates aggressive behavior and increases levels of homovanillic acid, a dopamine metabolite, in social isolation-reared mice

Background and aim

Early-life stress is thought to affect aggressive behavior in humans and rodents. Laboratory experiments have demonstrated that Sansoninto (SST; suān zǎo rén tāng), a traditional herbal medicine, attenuates stress-induced abnormal behavior in rodents. However, it is unknown whether SST attenuates stress-induced aggressive behavior. The current study examined the effects of SST on aggressive behavior of mice who suffered from social isolation (SI) stress in adolescence.

Experimental procedure

Five-week old mice were socially isolated for 6 weeks, and SST administration was started at 4 weeks after starting SI. Aggressive behavior and locomotor activity were examined in SST-treated mice. The content of dopamine and its metabolites in the hypothalamus were examined using high-performance liquid chromatography analysis. Gene expression analyses of monoamine oxidase-B (MAO-B), catechol-O-methyltransferase (COMT), and tyrosine hydroxylase in the hypothalamus were performed using quantitative reverse transcription polymerase chain reaction.

Results and conclusion

SST attenuated SI-induced aggressive behavior and increased levels of homovanillic acid, a metabolite of dopamine. However, SST did not affect dopamine levels. SI enhanced locomotion in a novel environment and increased COMT mRNA levels. In contrast, SST-treated mice showed no significant enhancement of locomotion. SST attenuated the increase in COMT mRNA levels. Given that the dopaminergic system has been implicated in aggressive behavior, these findings suggest that SST toned down dopaminergic signaling, resulting in amelioration of aggression. SST may be useful for treatment of aggressive behavior in patients with neurotic symptoms.

Effects of miR-143 and its target receptor 5-HT2B on agonistic behavior in the Chinese mitten crab (Eriocheir sinensis)

Chinese mitten crab (Eriocheir sinensis) as a commercially important species is widely cultured in China. However, E. sinensis is prone to agonistic behavior, which causes physical damage and wastes energy resources, negatively impacting their growth and survival. Therefore, understanding the regulatory mechanisms that underlie the switching of such behavior is essential for ensuring the efficient and cost-effective aquaculture of E. sinensis. The 5-HT2B receptor is a key downstream target of serotonin (5-HT), which is involved in regulating animal behavior. In this study, the full-length sequence of 5-HT2B gene was cloned. The total length of the 5-HT2B gene was found to be 3127 bp with a 236 bp 5′-UTR (untranslated region), a 779 bp 3′-UTR, and a 2112 bp open reading frame encoding 703 amino acids. Phylogenetic tree analysis revealed that the 5-HT2B amino acid sequence of E. sinensis is highly conserved with that of Cancer borealis. Using in vitro co-culture and luciferase assays, the miR-143 targets the 5-HT2B 3′-UTR and inhibits 5-HT2B expression was confirmed. Furthermore, RT-qPCR and Western blotting analyses revealed that the miR-143 mimic significantly inhibits 5-HT2B mRNA and protein expression. However, injection of miR-143 did not decrease agonistic behavior, indicating that 5-HT2B is not involved in the regulation of such behavior in E. sinensis.

Efficacy of Yokukansan, a traditional Japanese herbal medicine, in patients with dizziness and irritability

OBJECTIVE

Irritability is an emotional stress symptom that causes or exacerbates dizziness. Antidepressants may be helpful for some conditions that are accompanied by irritability; however, they do not completely inhibit irritability. Yokukansan (YKS), a traditional Japanese herbal medicine, has been used for neurosis, insomnia, and children's irritability and night crying. The study investigated the efficacy of YKS in nystagmus in patients with chronic dizziness and irritability.

METHODS

Twenty-two cases with chronic dizziness and irritability were reviewed retrospectively. The patients were divided into two groups: control patients (0-7 days of treatment) and YKS-treated patients (YKS cases; >7 days of treatment). Dizziness before and during (after, in the controls) YKS treatment was evaluated by scoring the nystagmus intensity on a 5-point scale. The average scores were calculated within a maximum of 6 months before and during or after treatment. The normalized scores were also calculated. The optimal treatment regimen was calculated via receiver operating characteristic (ROC) curve analysis.

RESULTS

There were six control cases (1 male, 5 females; mean age: 59.5 years). There were 16 YKS cases (3 males, 13 females; mean age: 61.8 years). While the group mean nystagmus intensity scores significantly decreased from 1.18 to 0.73 in the YKS cases, it did not change in the control cases. The group mean of the normalized nystagmus intensity scores during treatment was 0.73 in the YKS cases. The results of the ROC curve analysis indicated the optimal cut-off period of the YKS treatment was 10 days.

CONCLUSION

The oral administration of YKS for more than 10 days was optimal. The treatments with YKS could be a good option for the treatments of vertigo.

A Japanese herbal medicine attenuates anxiety-like behavior through GABAA receptor and brain-derived neurotrophic factor expression in a rat model of premenstrual syndrome

Inochinohaha White (IHW) is a Japanese herbal medicine for treating women with anxiety associated with premenstrual syndrome (PMS). In this study, we examined the effects of IHW on anxiety-like behavior in rats undergoing progesterone withdrawal (PWD), a model for PMS. Female rats were injected daily with progesterone for 21 days. Water and ethanol extracts of IHW (WE-IHW and EE-IHW, respectively) were administered orally 15 days after the initiation of progesterone injections. Anxiety-like behavior in an elevated plus maze was evaluated 48 h after the final injection of progesterone. PWD induced anxiety-like behavior, and EE-IHW (300 mg/kg), but not WE-IHW, significantly attenuated this behavior. Administration of the GABA agonists, diazepam or muscimol, significantly attenuated PWD-induced anxiety-like behavior. To investigate the underlying mechanisms of IHW action, we analyzed GABAA receptor expression in the amygdala of these rats. EE-IHW ameliorated the PWD-induced decrease in GABAA receptor β2-subunit mRNA, although β2-subunit protein was unchanged. Brain-derived neurotrophic factor (BDNF) has been reported to have anxiolytic effects and enhance GABAergic synaptic transmission. We found that EE-IHW increased BDNF levels in a dose-dependent manner. Our results suggest that EE-IHW attenuates PWD-induced anxiety-like behavior by increasing GABAA receptor-mediated signaling via increases in β2-subunit and BDNF in the amygdala.

Yokukansankachimpihange, a traditional Japanese (Kampo) medicine, enhances the adaptation to circadian rhythm disruption by increasing endogenous melatonin levels

The traditional Japanese (Kampo) medicines yokukansan (YKS) and yokukansankachimpihange (YKSCH) have similar formulas and the same indications. In animals or cultured cells, the neuropharmacological actions of YKS are sometimes more beneficial than those of YKSCH. Since both drugs are used to treat sleep disorders in Japan, we examined the ameliorative effects of YKS and YKSCH on circadian rhythm disturbance and compared their efficacy using a mouse model of circadian rhythm disruption. Ramelteon was used as the positive control. Ramelteon treatment significantly reversed decreased running wheel activity during the advanced dark phase, indicating facilitation of circadian adaptation. YKS treatment also reversed the activity in the early period of drug treatment; however, it was not statistically significant. YKSCH treatment significantly reversed the decreased activity during the advanced dark phase. Plasma melatonin (MT) levels were significantly increased in the YKSCH but not in the YKS group. The ameliorative effect of YKSCH on rhythm disruption was significantly inhibited by coadministration of the MT₂ receptor antagonist. Therefore, the therapeutic effect of YKSCH on circadian rhythm disruption would be attributable, to elevated endogenous MT levels. Taken together, YKS and YKSCH have different pharmacological properties and may be more precisely prescribed depending on patients' psychological symptoms.