The Japanese Angelica acutiloba root and yokukansan increase hippocampal acetylcholine level, prevent apoptosis and improve memory in a rat model of repeated cerebral ischemia.

ETHNOPHARMACOLOGICAL RELEVANCE: Japanese Angelica acutiloba root (Angelica root) is included in several Kampo medicines including Yokukansan (YKS). Angelica root and YKS are used for the treatment of a variety of psychological and neurodegenerative disorders. Development of safe and effective therapeutic agents against cerebrovascular disorders will improve the treatment of patients with dementia. AIM OF THE STUDY: The effect of Angelica root and YKS on ischemia-impaired memory has not yet been fully investigated. The present study investigated whether Angelica root is also involved in memory improving and neuroprotective effect of YKS in a model of cerebrovascular ischemia. MATERIALS AND METHODS: Male Wistar rats grouped into sham rats received saline, and other three groups subjected to repeated cerebral ischemia induced by 4-vessel occlusion (4-VO), received a 7-day oral administration of either saline, Angelica root or YKS. Memory was evaluated by eight-arm radial maze task. Acetylcholine release (ACh) in the dorsal hippocampus was investigated by microdialysis-HPLC. Apoptosis was determined by terminal deoxynucleotidyl transferase (TdT)-mediated fluorescein-deoxyuridine triphosphate (dUTP) nick-end labeling. RESULTS: Ischemia induced apoptosis, reduced release of ACh, and impaired the memory (increased error choices and decreased correct choices). Angelica root and YKS improved the memory deficits, upregulated the release of ACh and prevented 4-VO-induced hippocampal apoptosis. CONCLUSION: The dual ACh-increasing and neuroprotective effect of Angelica root could make it a promising therapeutic agent useful for the treatment of symptoms of cerebrovascular dementia. Angelica root could be one of the components contributing to the memory-improving and neuroprotective effects of YKS.

Cholinergic involvement and synaptic dynamin 1 expression in Yokukansan-mediated improvement of spatial memory in a rat model of early Alzheimer's disease.

The aim of this study was to investigate the effect of Yokukansan (YKS) on the impairment of spatial memory and cholinergic involvement in a rat model of early-phase Alzheimer's disease (AD). In this model, rats underwent four-vessel transient cerebral ischemia and then were treated with beta amyloid oligomers injected intracerebroventricularly once daily for 7 days. These animals showed memory impairment in an eight-arm radial maze task without histological evidence of apoptosis but with a decrease in expression of hippocampal dynamin 1, an important factor in synaptic vesicle endocytosis. Oral administration of YKS for 2 weeks significantly increased the number of correct choices and decreased the number of error choices in the eight-arm radial maze task (P < 0.05). Moreover, YKS significantly increased high K⁺-evoked potentiation of acetylcholine (ACh) release (P < 0.05) and significantly increased the expression of dynamin 1 (P < 0.01) in the hippocampus. The ameliorative effect of YKS on spatial memory impairment in our rat model of early-phase AD may be mediated in part by an increase in ACh release and modulation of dynamin 1 expression, leading to improved synaptic function. Future studies will determine whether YKS is similarly useful in the treatment of memory defects in patients diagnosed with early-stage AD.

Yokukansan enhances pentobarbital-induced sleep in socially isolated mice: possible involvement of GABA(A)-benzodiazepine receptor complex.

In the present study, we investigated the effect of the Kampo medicine Yokukansan (YKS) on pentobarbital-induced sleep in group-housed and socially isolated mice. Socially isolated mice showed shorter sleeping time than the group-housed mice. YKS (300 mg/kg, p.o.) prolonged the pentobarbital-induced sleeping time in socially isolated mice without affecting pentobarbital sleep in group-housed mice. The prolongation of sleeping time by YKS was reversed by bicuculline (3 mg/kg, i.p.) and flumazenil (3 mg/kg, i.p.), but not WAY100635. These findings suggest that the GABA(A)-benzodiazepine receptor complex, but not 5-HT(1A) receptors, is involved in the reversal effect of YKS on the decrease of pentobarbital sleep by social isolation.

Yokukansan Enhances Pentobarbital-Induced Sleep in Socially Isolated Mice: Possible Involvement of GABA(A) - Benzodiazepine Receptor Complex.

In the present study, we investigated the effect of the Kampo medicine Yokukansan (YKS) on pentobarbital-induced sleep in group-housed and socially isolated mice. Socially isolated mice showed shorter sleeping time than the group-housed mice. YKS (300 mg/kg, p.o.) prolonged the pentobarbital-induced sleeping time in socially isolated mice without affecting pentobarbital sleep in group-housed mice. The prolongation of sleeping time by YKS was reversed by bicuculline (3 mg/kg, i.p.) and flumazenil (3 mg/kg, i.p.), but not WAY100635. These findings suggest that the GABA(A) - benzodiazepine receptor complex, but not 5-HT(1A) receptors, is involved in the reversal effect of YKS on the decrease of pentobarbital sleep by social isolation.

Effects of yokukansan on anxiety-like behavior in a rat model of cerebrovascular dementia.

Behavioral and psychological symptoms of dementia (BPSD) are commonly seen in patients with dementia. Current pharmacological approaches to treatment are inadequate, despite the availability of serotonergic agents to ameliorate anxiety, one of the symptoms of BPSD. The herbal medicine yokukansan has been demonstrated to improve BPSD in a randomized, single-blinded, placebo-controlled study. However, the mechanisms of the anxiolytic effect of yokukansan have not been clarified. There are also no reports on the anxiolytic effect of yokukansan in cerebrovascular ischemia models. In this study, we examined whether rats subjected to repeated cerebral ischemia exhibited anxiety-like behavior in a plus-maze task, a light/dark box test and an open-field task. We then investigated the effect of yokukansan on anxiety-like behavior in ischemic rats. Repeated ischemia was induced by the four-vessel occlusion method in which a 10-min ischemic episode was repeated once after 60 min. Yokukansan was orally administered once a day for 14 days from 7 days before ischemia induction. The last administration was performed 1 h before the behavioral experiments. The ischemic rats showed anxiety-like behavior in all three tasks, suggesting that this rat may be a good model for anxiety in cerebrovascular dementia. Yokukansan exhibited anxiolytic effects on the anxiety-like behavior in rats subjected to repeated cerebral ischemia, and exerted antagonistic effects on the wet-dog shakes induced by 1-(2,5-dimethoxy-4-indophenyl)-2-amino propane, a serotonin receptor (5-HT(2A)) agonist. This study revealed that yokukansan shows anxiolytic effects not only in normal animals but also in cerebrovascular model rats.

Yokukansan inhibits social isolation-induced aggression and methamphetamine-induced hyperlocomotion in rodents.

Behavioral and psychological symptoms of dementia (BPSD) are commonly seen in patients with Alzheimer's disease (AD) and other forms of senile dementia. BPSD have a serious impact on the quality of life of dementia patients, as well as on that of their caregivers. However, effective drug therapy for BPSD has not been established. Recently, the traditional Japanese medicine Yokukansan (YKS, Yi-gan san in Chinese) has been reported to improve BPSD, such as aggression, agitation, irritability, and hallucinations, in a randomized, single-blind, placebo-controlled study. However, the psychopharmacologic effects of YKS remain unexplored. In the present study, we investigated the effects of YKS on social isolation-induced aggressive behavior and methamphetamine- or MK-801-induced hyperlocomotion in rodents. Social isolation markedly induced aggressive behavior in male Wistar rats. Quetiapine at a dose of 10 mg/kg (per os (p.o.)) significantly inhibited this social isolation-induced aggressive behavior. YKS (100, 300 mg/kg, p.o.) also significantly inhibited the aggressive behavior. Moreover, risperidone (0.1 mg/kg, p.o.) significantly inhibited methamphetamine- or MK-801-induced hyperlocomotion in mice. YKS (300 mg/kg, p.o.) inhibited methamphetamine-induced hyperlocomotion, while YKS at the same dose had no effect on MK-801-induced hyperlocomotion. These findings suggest that YKS may be useful for the treatment of aggression and agitation, and that the psychopharmacologic effects of YKS might be mediated, in part, by inhibiting the activity of the dopaminergic system.

Cannabidiol prevents a post-ischemic injury progressively induced by cerebral ischemia via a high-mobility group box1-inhibiting mechanism.

We examined the cerebroprotective mechanism of cannabidiol, the non-psychoactive component of marijuana, against infarction in a 4-h mouse middle cerebral artery (MCA) occlusion model. Cannabidiol was intraperitoneally administrated immediately before and 3h after cerebral ischemia. Infarct size and myeloperoxidase (MPO) activity, a marker of neutrophil, monocyte/macropharge, were measured at 24h after cerebral ischemia. Activated microglia and astrocytes were evaluated by immunostaining. Moreover, high-mobility group box1 (HMGB1) was also evaluated at 1 and 3 days after MCA occlusion. In addition, neurological score and motor coordination on the rota-rod test were assessed at 1 and 3 days after cerebral ischemia. Cannabidiol significantly prevented infarction and MPO activity at 20h after reperfusion. These effects of cannabidiol were not inhibited by either SR141716 or AM630. Cannabidiol inhibited the MPO-positive cells expressing HMGB1 and also decreased the expression level of HMGB1 in plasma. In addition, cannabidiol decreased the number of Iba1- and GFAP-positive cells at 3 days after cerebral ischemia. Moreover, cannabidiol improved neurological score and motor coordination on the rota-rod test. Our results suggest that cannabidiol inhibits monocyte/macropharge expressing HMGB1 followed by preventing glial activation and neurological impairment induced by cerebral ischemia. Cannabidiol will open new therapeutic possibilities for post-ischemic injury via HMGB1-inhibiting mechanism.

Repeated administration of Yokukansan inhibits DOI-induced head-twitch response and decreases expression of 5-hydroxytryptamine (5-HT)2A receptors in the prefrontal cortex.

Behavioral and psychological symptoms of dementia (BPSD) are commonly seen in patients with Alzheimer's disease (AD) and other forms of senile dementia. BPSD have a serious impact on the quality of life of dementia patients, as well as their caregivers. However, an effective drug therapy for BPSD has not been established. Recently, the traditional Japanese medicine Yokukansan (YKS, Yi-gan san in Chinese) has been reported to improve BPSD in a randomized, single-blind, placebo-controlled study. Moreover, abnormalities of the serotonin (5-HT) system such as 5-HT2A receptors have been reported to be associated with BPSD of AD patients. In the present study, we investigated the effect of YKS on head-twitch response induced by 2,5-dimethoxy-4-iodoamphetamine (DOI, 5 mg/kg, i.p.) in mice, a behavioral response that is mediated, in part, by 5-HT2A receptors. Acute treatment with YKS (100 and 300 mg/kg, p.o.) had no effect on the DOI-induced head-twitch response, whilst 14 days repeated treatment with YKS (300 mg/kg, p.o.) significantly inhibited this response. Moreover, repeated treatment with YKS (300 mg/kg, p.o.) decreased expression of 5-HT2A receptors in the prefrontal cortex, which is part of the circuitry mediating the head-twitch response. These findings suggest that the inhibition of DOI-induced head-twitch response by YKS may be mediated, in part, by altered expression of 5-HT2A receptors in the prefrontal cortex, which suggests the involvement of the 5-HT system in psychopharmacological effects of YKS.