Ameliorative effects of yokukansan on learning and memory deficits in olfactory bulbectomized mice

Donepezil prevents olfactory dysfunction and α-synuclein aggregation in the olfactory bulb by enhancing autophagy in zinc sulfate-treated mice

Alzheimer's disease is associated with marked olfactory dysfunction observed in the early stages. Clinical studies reported that acetylcholinesterase inhibitor donepezil (DNP) attenuated this deficit; however, the underlying mechanism remains unclear. Herein, we aimed to examine the effects and underlying mechanisms of DNP on olfactory deficits in zinc sulfate (ZnSO₄) nasal-treated mice, which were used as a model of reversible olfactory impairment. We evaluated olfactory function using the buried food finding test and neurogenesis in the subventricular zone (SVZ) using immunohistochemistry. Finally, we measured the expression of doublecortin (DCX), neuronal nuclear antigen (NeuN), olfactory marker protein, tyrosine hydroxylase (TH), tryptophan hydroxylase 2, glutamic acid decarboxylase 67, p-α-synuclein (Ser129), α-synuclein, p-AMPK, p-p70S6 kinase (p70S6K) (Thr389), LC3 Ⅱ/Ⅰ, and p-p62 in the olfactory bulb (OB) by western blotting. On day 7 after treatment, ZnSO₄-treated mice exhibited prolonged time to find the buried food, cell proliferation enhancement in the SVZ, increased NeuN, p-α-synuclein (Ser129), and α-synuclein levels, and decreased DCX and TH levels in the OB; except for TH, these changes normalized on day 14 after treatment. Repeated administration of DNP prevented the ZnSO₄-induced changes on day 7 after treatment. Moreover, DNP increased p-AMPK and LC3 Ⅱ/Ⅰ, and decreased p-p70S6K and p-p62 (Ser351) levels in the OB, suggesting that DNP enhances autophagy in the OB. These findings indicate that DNP may help prevent olfactory dysfunction by autophagy that reduces α-synuclein aggregation via the AMPK/mTOC1 pathway.

Traditional uses, chemical compounds, pharmacological activities and clinical studies on the traditional Chinese prescription Yi-Gan San

ETHNOPHARMACOLOGICAL RELEVANCE

A widely used traditional prescription, Yi-Gan San (YGS) is a remedy for neurodegenerative disorders. The formulation consists of seven Chinese medicinal materials in specific proportions, namely Uncariae Ramulus cum Uncis (Uncaria rhynchophylla (Miq.) Miq. ex Havil.), Bupleuri Radix (Bupleurum chinense DC.), Angelicae Sinensis Radix (Angelica sinensis (Oliv.) Diels), Chuanxiong Rhizoma (Ligusticum wallichii Franch.), Poria (Poria cocos (Schw.) Wolf), Atractylodis Macrocephalae Rhizoma (Atractylodes macrocephala Koidz.) and Glycyrrhizae Radix et Rhizoma (Glycyrrhiza uralensis Fisch.). Using YGS has been shown to alleviate various behavioural and psychological symptoms of dementia (BPSD).

AIM OF THIS REVIEW

The goal of this review is to give up-to-date information about the traditional uses, chemistry, pharmacology and clinical efficacy of YGS based on the scientific literature and to learn the current focus and provide references in the next step.

MATERIALS AND METHODS

The database search room was accessed using the search terms "Yi-Gan San" and "Yokukansan" to obtain results from resources such as Web of Science, PubMed, Google Scholar and Sci Finder Scholar. We not only consulted the literature of fellow authors for this review but also explored classical medical books.

RESULTS

YGS has been used to cure neurosis, sleeplessness, night weeping and restlessness in infants. Its chemical components primarily consist of triterpenes, flavonoids, phenolics, lactones, alkaloids and other types of compounds. These active ingredients displayed diverse pharmacological activities to ameliorate BPSD by regulating serotonergic, glutamatergic, cholinergic, dopaminergic, adrenergic, and GABAergic neurotransmission. In addition, YGS showed neuroprotective, antistress, and anti-inflammatory effects. The majority of cases of neurodegenerative disorders are treated with YGS, including Alzheimer's disease and dementia with Lewy bodies.

CONCLUSIONS

Based on previous studies, YGS has been used as a traditional prescription in East Asia, such as Japan, Korea and China, and it has diverse chemical compounds and multiple pharmacological activities. Nevertheless, few experimental studies have focused on chemical and quantitative YGS studies, suggesting that further comprehensive research on its chemicals and quality assessments is critical for future evaluations of drug efficacy.

Sulforaphane Increase Mitochondrial Biogenesis-Related Gene Expression in the Hippocampus and Suppresses Age-Related Cognitive Decline in Mice

Sulforaphane (SFN) is a potent activator of the transcriptional factor, Nuclear Factor Erythroid 2 (NF-E2)-Related factor 2 (NRF2). SFN and its precursor, glucoraphanin (sulforaphane glucosinolate, SGS), have been shown to ameliorate cognitive function in clinical trials and in vivo studies. However, the effects of SGS on age-related cognitive decline in Senescence-Accelerated Mouse Prone 8 (SAMP8) is unknown. In this study, we determined the preventive potential of SGS on age-related cognitive decline. One-month old SAMP8 mice or control SAM resistance 1 (SAMR1) mice were fed an ad libitum diet with or without SGS-containing broccoli sprout powder (0.3% w/w SGS in diet) until 13 months of age. SGS significantly improved long-term memory in SAMP8 at 12 months of age. Interestingly, SGS increased hippocampal mRNA and protein levels of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC1α) and mitochondrial transcription factor A (TFAM), which are master regulators of mitochondrial biogenesis, both in SAMR1 and SAMP8 at 13 months of age. Furthermore, mRNAs for nuclear respiratory factor-1 (NRF-1) and mitochondrial DNA-encoded respiratory complex enzymes, but not mitochondrial DNA itself, were increased by SGS in SAMP8 mice. These results suggest that SGS prevents age-related cognitive decline by maintaining mitochondrial function in senescence-accelerated mice.

Ursolic acid and its isomer oleanolic acid are responsible for the anti-dementia effects of Ocimum sanctum in olfactory bulbectomized mice

This study aims to clarify the bioactive constituents responsible for the anti-dementia effects of Ocimum sanctum Linn. ethanolic extract (OS) using olfactory bulbectomized (OBX) mice, an animal model of dementia. The effects of OS or its extract further fractionated with n-hexane (OS-H), ethyl acetate (OS-E), and n-butanol (OS-B) on the spatial cognitive deficits of OBX mice were elucidated by the modified Y-maze tests. The effects of the major constituents of the most active OS fraction were also elucidated using the reference drug donepezil. The administration of OS and OS-E ameliorated the spatial cognitive deficits caused by OBX, whereas OS-H or OS-B had no effect. Two major constituents, ursolic acid (URO) and oleanolic acid (OLE), and three minor constituents were isolated from OS-E. URO (6 and 12 mg/kg) and OLE (24 mg/kg) attenuated the OBX-induced cognitive deficits. URO (6 mg/kg) and donepezil reversed the OBX-induced down-regulation of vascular endothelial growth factor (VEGF) and choline acetyltransferase expression levels in the hippocampus. URO inhibited the ex vivo activity of acetylcholinesterase with similar efficacy to donepezil. URO inhibited the in vitro activity of acetylcholinesterase (IC50 = 106.5 μM), while the effects of OS, OS-E, and other isolated compounds were negligible. These findings suggest that URO and OLE are responsible for the anti-dementia action of OS extract, whereas URO possesses a more potent anti-dementia effect than its isomer OLE. The effects of URO are, at least in part, mediated by normalizing the function of central cholinergic systems and VEGF protein expression.

Ocimum sanctum Linn. Extract Improves Cognitive Deficits in Olfactory Bulbectomized Mice via the Enhancement of Central Cholinergic Systems and VEGF Expression

This study aimed to clarify the antidementia effects of ethanolic extract of Ocimum sanctum Linn. (OS) and its underlying mechanisms using olfactory bulbectomized (OBX) mice. OBX mice were treated daily with OS or a reference drug, donepezil (DNP). Spatial and nonspatial working memory performance was measured using a modified Y maze test and a novel object recognition test, respectively. Brain tissues of the animals were subjected to histochemical and neurochemical analysis. OS treatment attenuated OBX-induced impairment of spatial and nonspatial working memories. OBX induced degeneration of septal cholinergic neurons, enlargement of the lateral ventricles, and suppression of hippocampal neurogenesis. OS and DNP treatment also depressed these histological damages. OS administration reduced ex vivo activity of acetylcholinesterase in the brain. OBX diminished the expression levels of genes coding vascular endothelial growth factor (VEGF) and VEGF receptor type 2 (VEGFR2). Treatment with OS and DNP reversed OBX-induced decrease in VEGF gene and protein expression levels without affecting the expression of the VEGFR2 gene. These results demonstrate that the administration of OS can lessen the cognitive deficits and neurohistological damages of OBX and that these actions are, at least in part, mediated by the enhancement of central cholinergic systems and VEGF expression.

Cognitive Effects of Astaxanthin Pretreatment on Recovery From Traumatic Brain Injury

Traumatic brain injury (TBI), caused by mechanical impact to the brain, is a leading cause of death and disability among young adults, with slow and often incomplete recovery. Preemptive treatment strategies may increase the injury resilience of high-risk populations such as soldiers and athletes. In this work, the xanthophyll carotenoid Astaxanthin was examined as a potential nutritional preconditioning method in mice (sabra strain) to increase their resilience prior to TBI in a closed head injury (CHI) model. The effect of Astaxanthin pretreatment on heat shock protein (HSP) dynamics and functional outcome after CHI was explored by gavage or free eating (in pellet form) for 2 weeks before CHI. Assessment of neuromotor function by the neurological severity score (NSS) revealed significant improvement in the Astaxanthin gavage-treated group (100 mg/kg, ATX) during recovery compared to the gavage-treated olive oil group (OIL), beginning at 24 h post-CHI and lasting throughout 28 days (p < 0.007). Astaxanthin pretreatment in pellet form produced a smaller improvement in NSS vs. posttreatment at 7 days post-CHI (p < 0.05). Cognitive and behavioral evaluation using the novel object recognition test (ORT) and the Y Maze test revealed an advantage for Astaxanthin administration via free eating vs. standard chow during recovery post-CHI (ORT at 3 days, p < 0.035; improvement in Y Maze score from 2 to 29 days, p < 0.02). HSP profile and anxiety (open field test) were not significantly affected by Astaxanthin. In conclusion, astaxanthin pretreatment may contribute to improved recovery post-TBI in mice and is influenced by the form of administration.

Bacopa monnieri (L.) Wettst. Extract Improves Memory Performance via Promotion of Neurogenesis in the Hippocampal Dentate Gyrus of Adolescent Mice

Bacopa monnieri L. Wettst. (BM) is a botanical component of Ayurvedic medicines and of dietary supplements used worldwide for cognitive health and function. We previously reported that administration of BM alcoholic extract (BME) prevents trimethyltin (TMT)-induced cognitive deficits and hippocampal cell damage and promotes TMT-induced hippocampal neurogenesis. In this study, we demonstrate that administration of BME improves spatial working memory in adolescent (5-week- old) healthy mice but not adult (8-week-old) mice. Moreover, improved spatial working memory was retained even at 4 weeks after terminating 1-week treatment of adolescent mice. One-week BME treatment of adolescent mice significantly enhanced hippocampal BrdU incorporation and expression of genes involved in neurogenesis determined by RNAseq analysis. Cell death, as detected by histochemistry, appeared not to be significant. A significant increase in neurogenesis was observed in the dentate gyrus region 4 weeks after terminating 1-week treatment of adolescent mice with BME. Bacopaside I, an active component of BME, promoted the proliferation of neural progenitor cells in vitro in a concentration-dependent manner via the facilitation of the Akt and ERK1/2 signaling. These results suggest that BME enhances spatial working memory in healthy adolescent mice by promoting hippocampal neurogenesis and that the effects of BME are due, in significant amounts, to bacopaside I.

Caffeine prevents neurodegeneration and behavioral alterations in a mice model of agitated depression

Longitudinal and some experimental studies have showed the potential of caffeine to counteract some depressive behaviors and synaptic dysfunctions. In this study, we investigated the potential of caffeine in preventing behavioral outcomes, neurodegeneration and synaptic proteins alterations in a mice model of agitated depression by bilateral olfactory bulbectomy (OB). For this purpose, bulbectomized mice received caffeine (0.3 g/L and 1.0 g/L, drinking water), during the active cycle, for seven weeks (two before the surgery and throughout five weeks after OB). Caffeine prevented OB-induced hyperactivity and recognition memory impairment and rescue self care and motivational behavior. In the frontal cortex, bulbectomized mice presented increase in the adenosine A₁ receptors (A₁R) and GFAP, while adenosine A_2A receptors (A_2AR) increased in the hippocampus and striatum and SNAP-25 was decreased in frontal cortex and striatum. Caffeine increased A₁R in the striatum of bulbectomized mice and in SHAM-water group caffeine increased A_2AR in the striatum and decreased SNAP-25 in the frontal cortex. Astrogliosis observed in the polymorphic layer of the dentate gyrus of OB mice was prevented by caffeine as well as the neurodegeneration in the striatum and piriform cortex. Based on these behavioral and neurochemical evidences, caffeine confirms its efficacy in preventing neurodegeneration associated with memory impairment and may be considered as a promising therapeutic tool in the prophylaxis and/or treatment of depression.

Ouabain activates transcription factor EB and exerts neuroprotection in models of Alzheimer's disease

The number of neurofibrillary tangles containing abnormal hyperphosphorylated tau protein correlates with the degree of dementia in Alzheimer's disease (AD). In addition, autophagosome accumulation and disturbance of autophagy, the process by which toxic aggregate proteins are degraded in the cytosol, are also found in AD models. These indicate that regulation of the autophagy-lysosome system may be a potential therapeutic target for AD. Activation of transcription factor EB (TFEB), a master regulator of autophagy-lysosome system gene transcription, reduces the amount of tau in APP mice. Here, to identify potential therapeutic compounds for AD, we performed two types of screening to determine pharmacologically active compounds that increase 1) neuronal viability in okadaic acid-induced tau hyperphosphorylation-related neurodegeneration models and 2) nuclear localization of TFEB in high-contents screening. Ouabain, a cardiac glycoside, was discovered as a common hit compound in both screenings. It also exhibited a significant protective effect in tau transgenic fly and mouse models in vivo. This work demonstrates that ouabain enhances activation of TFEB through inhibition of the mTOR pathway and induces downstream autophagy-lysosomal gene expression and cellular restorative properties. Therefore, therapeutic approaches using ouabain reduce the accumulation of abnormal toxic tau in vitro and in vivo.

Orengedokuto and san'oshashinto improve memory deficits by inhibiting aging-dependent activation of glycogen synthase kinase-3β

Background and aim

The aging-dependent activation of glycogen synthase kinase-3β (GSK-3β) has been suggested to be important in the onset of dementia. To discover novel therapeutic Kampo medicines for dementia, we examined the effects of orengedokuto (OGT; 黃連解毒湯 huáng lián jiědú tāng) and san'oshashinto (SST; 三黃瀉心湯 sān huáng xiè xīn tāng) on memory deficits and GSK-3β activity in senescence-accelerated prone mice (SAMP8).

Experimental procedure

The object recognition test (ORT) and conditioned fear memory test (CFT) were employed to elucidate short-term working memory and long-term fear memory. The activity of GSK-3β and the phosphorylation of related molecules were measured using a kinase assay and Western blotting.

Results and conclusion

OGT and SST attenuated memory deficits in SAMP8 in ORT, but not in CFT. In ex vivo experiments, cortical GSK-3β activity was significantly stronger in SAMP8 than in SAMR1. The enhanced cortical GSK-3β activity in SAMP8 was accompanied by a significant increase in the level of phosphorylated collapsin response mediator protein-2 (CRMP2), an important factor that is involved in the regulation of microtubule stability. OGT and SST attenuated not only increases in cortical GSK-3β activity, but also the levels of phosphorylated CRMP2 in SAMP8. In vitro experiments, flavonoids contained in these kampo medicines, inhibited GSK-3β activity in concentration-dependent manners. These results suggest that OGT and SST prevent aging-induced short-term working memory deficits by inhibiting aging-dependent elevations in the cortical GSK-3β activity and subsequent CRMP2 phosphorylation.

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OGT and SST attenuated short-term working memory deficits in SAMP8.

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Age-dependent cortical GSK-3β activation was suppressed by OGT and SST.

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OGT and SST also attenuated the levels of phosphorylated CRMP2 in SAMP8.

Potential Application of Yokukansan as a Remedy for Parkinson’s Disease

Parkinson’s disease (PD), the second most common progressive neurodegenerative disorder, is characterized by complex motor and nonmotor symptoms. The clinical diagnosis of PD is defined by bradykinesia and other cardinal motor features, although several nonmotor symptoms are also related to disability, an impaired quality of life, and shortened life expectancy. Levodopa, which is used as a standard pharmacotherapy for PD, has limitations including a short half-life, fluctuations in efficacy, and dyskinesias with long-term use. There have been efforts to develop complementary and alternative therapies for incurable PD. Yokukansan (YKS) is a traditional herbal medicine that is widely used for treating neurosis, insomnia, and night crying in children. The clinical efficacy of YKS for treating behavioral and psychological symptoms, such as delusions, hallucinations, and impaired agitation/aggression subscale and activities of daily living scores, has mainly been investigated in the context of neurological disorders such as PD, Alzheimer’s disease, and other psychiatric disorders. Furthermore, YKS has previously been found to improve clinical symptoms, such as sleep disturbances, neuropsychiatric and cognitive impairments, pain, and tardive dyskinesia. Preclinical studies have reported that the broad efficacy of YKS for various symptoms involves its regulation of neurotransmitters including GABA, serotonin, glutamate, and dopamine, as well as the expression of dynamin and glutamate transporters, and changes in glucocorticoid hormones and enzymes such as choline acetyltransferase and acetylcholinesterase. Moreover, YKS has neuroprotective effects at various cellular levels via diverse mechanisms. In this review, we focus on the clinical efficacy and neuropharmacological effects of YKS. We discuss the possible mechanisms underpinning the effects of YKS on neuropathology and suggest that the multiple actions of YKS may be beneficial as a treatment for PD. We highlight the potential that YKS may serve as a complementary and alternative strategy for the treatment of PD.

Potential Application of Yokukansan as a Remedy for Parkinson's Disease

Parkinson's disease (PD), the second most common progressive neurodegenerative disorder, is characterized by complex motor and nonmotor symptoms. The clinical diagnosis of PD is defined by bradykinesia and other cardinal motor features, although several nonmotor symptoms are also related to disability, an impaired quality of life, and shortened life expectancy. Levodopa, which is used as a standard pharmacotherapy for PD, has limitations including a short half-life, fluctuations in efficacy, and dyskinesias with long-term use. There have been efforts to develop complementary and alternative therapies for incurable PD. Yokukansan (YKS) is a traditional herbal medicine that is widely used for treating neurosis, insomnia, and night crying in children. The clinical efficacy of YKS for treating behavioral and psychological symptoms, such as delusions, hallucinations, and impaired agitation/aggression subscale and activities of daily living scores, has mainly been investigated in the context of neurological disorders such as PD, Alzheimer's disease, and other psychiatric disorders. Furthermore, YKS has previously been found to improve clinical symptoms, such as sleep disturbances, neuropsychiatric and cognitive impairments, pain, and tardive dyskinesia. Preclinical studies have reported that the broad efficacy of YKS for various symptoms involves its regulation of neurotransmitters including GABA, serotonin, glutamate, and dopamine, as well as the expression of dynamin and glutamate transporters, and changes in glucocorticoid hormones and enzymes such as choline acetyltransferase and acetylcholinesterase. Moreover, YKS has neuroprotective effects at various cellular levels via diverse mechanisms. In this review, we focus on the clinical efficacy and neuropharmacological effects of YKS. We discuss the possible mechanisms underpinning the effects of YKS on neuropathology and suggest that the multiple actions of YKS may be beneficial as a treatment for PD. We highlight the potential that YKS may serve as a complementary and alternative strategy for the treatment of PD.

Endogenous acetylcholine regulates neuronal and astrocytic vascular endothelial growth factor expression levels via different acetylcholine receptor mechanisms

Vascular endothelial growth factor (VEGF), a signaling molecule involved in angiogenesis, plays an important role in neuroprotection and neurogenesis. In the present study, we aimed to elucidate the mechanisms underlying endogenous acetylcholine (ACh)-induced VEGF expression in neurons and astrocytes, and identify the neuronal cells contributing to its expression in the medial septal area, a nuclear origin of cholinergic neurons mainly projecting to the hippocampus. The mRNA expression and secretion of VEGF were measured by RT-PCR and ELISA using mouse primary cultured cortical neurons and astrocytes. VEGF expression in the medial septal area was assessed by RT-PCR and immunostaining using mice treated with tacrine [9-amino-1,2,3,4-tetrahydro-acridine HCl (THA); 2.5 mg/kg, i.p.] once daily for 7 days. The THA treatment increased VEGF mRNA expression in neurons in a manner that was reversed by mecamylamine, a nicotinic ACh receptor (AChR) antagonist, whereas in mouse primary cultured astrocytes, carbachol, but not THA dose-dependently increased VEGF mRNA expression and secretion in a manner that was inhibited by scopolamine, a muscarinic AChR inhibitor. In in vivo studies, the administration of THA significantly increased the expression of VEGF in medial septal cholinergic neurons and the effects of THA were significantly blocked by mecamylamine. THA also significantly increased the expression levels of a phosphorylated form of VEGF receptor 2 (p-VEGFR2), an activated form of VEGFR2. The present results suggest that endogenous ACh plays an up-regulatory role for VEGF expression in neurons and astrocytes via different mechanisms. Moreover, endogenous ACh-induced increases in VEGF levels appear to activate VEGFR2 on medial septal cholinergic neurons via an autocrine mechanism.

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.

Pharmacognostical Sources of Popular Medicine To Treat Alzheimer's Disease

BACKGROUND

A large number of classical and recently discovered plants are indicated in preventing and/or treating Alzheimer's disease (AD).

OBJECTIVE

Name of plants with their anti-AD effects are important for their further use and investigation.

METHOD

A short overview of AD is given; anti-Alzheimer plants are given in a Table.

RESULTS

Various medicinal plants are listed here as sources of popular medicines to be used in cases when patients are afraid of developing and/or suffer from AD. Some of these plants have been used for centuries. The major sources in the literature, over one hundred of references are given for plants that show beneficial effect on the progress of AD.

CONCLUSION

Plant extracts are widely used addition to the synthetic drugs approved by various administrative authorities to stop/slow down the progress of symptoms of AD.

Chemical composition and antibacterial, antifungal, allelopathic and acetylcholinesterase inhibitory activities of cassumunar-ginger

BACKGROUND

Zingiber montanum (J.Koenig) Link ex A.Dietr. (Zingiberaceae), commonly known as cassumunar-ginger, is a folk remedy for the treatment of inflammations, sprains, rheumatism and asthma. The aim of the present study was to assess the chemical composition, and antibacterial, antifungal, allelopathic and acetylcholinesterase inhibitory activities of the essential oil of Z. montanum originating from India.

RESULTS

The hydrodistilled essential oil of Z. montanum rhizome was analyzed using gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. A total of 49 constituents, forming 98.7-99.9% of the total oil compositions, was identified. The essential oil was characterized by higher amount of monoterpene hydrocarbons (32.6-43.5%), phenylbutanoids (27.5-41.2%) and oxygenated monoterpenes (11.4-34.1%). Major constituents of the oil were sabinene (13.5-38.0%), (E)-1-(3',4'-dimethoxyphenyl)buta-1,3-diene (DMPBD) (20.6-35.3%), terpinen-4-ol (9.0-31.3%), γ-terpinene (1.1-4.8%) and β-phellandrene (1.0-4.4%). The oil was evaluated against eight pathogenic bacteria and two fungal strains. It exhibited low to good antibacterial activity (minimum inhibitory concentration: 125-500 µg mL-1 ) and moderate antifungal activity (250 µg mL-1 ) against the tested strains. The oil reduced germination (69.8%) and inhibited the root and shoot growth of lettuce significantly (LD50 : 3.58 µL plate-1 ). However, it did not demonstrate acetylcholinesterase inhibitory activity up to a concentration of 10 mg mL-1 .

CONCLUSIONS

The essential oil of Z. montanum can be used as a potential source of DMPBD, terpinen-4-ol and sabinene for pharmaceutical products. The results of the present study add significant information to the pharmacological activity of Z. montanum native to India. © 2017 Society of Chemical Industry.

Sansoninto, a traditional herbal medicine, ameliorates behavioral abnormalities and down-regulation of early growth response-1 expression in mice exposed to social isolation stress

Social isolation (SI) mice exhibit behavioral abnormalities such as impairments of sociability- and attention-like behaviors, offering an animal model of neurodevelopmental disorders such as attention-deficit/hyperactivity disorder (ADHD). This study aimed to identify the effects of Sansoninto (SST; 酸棗仁湯 suān zǎo rén tāng) on the psychiatric symptoms related to ADHD using SI mice. Four-week-old mice were socially isolated during the experimental period, and SST administration (800 or 2400 mg/kg, p.o.) was started at 2 weeks after starting SI. SST ameliorated SI-induced impairments of sociability- and attention-like behaviors in a dose-dependent manner, and tended to ameliorate contextual- and auditory-dependent fear memory deficit. Moreover, the expression level of Egr-1 was down-regulated by SI stress, and was restored by a high dose of SST. These findings suggest that SST is useful for improvement of psychiatric disorders such as ADHD.

Daily administration of yokukansan and keishito prevents social isolation-induced behavioral abnormalities and down-regulation of phosphorylation of neuroplasticity-related signaling molecules in mice

BACKGROUND

Our previous studies demonstrated that post-weaning social isolation (ISO) in mice induces behavior abnormalities such as deficits of sociability- and attention-like behaviors. These deficits can be attenuated by methylphenidate (MPH), a drug used for attention deficit hyperactivity disorder (ADHD), suggesting that ISO mice offer a potential animal model of comorbid developmental disorder with ADHD and autism spectrum disorder symptoms. This study investigated the effects of Kampo formulae, yokukansan (YKS) and keishito (KST), on the neuropsychiatric symptoms of ISO mice to clarify the therapeutic or preventive/delaying potential of these formulae for the treatment of neurodevelopmental disorders.

METHODS

Three-to-4-week old male ICR mice were socially isolated during an experimental period and YKS and KST (1523.6 and 2031.8 mg/kg, p.o.) was administered starting from week 2 and week 0 after starting ISO for the analysis of their therapeutic and preventive/delaying potentials, respectively. Sociability, attention-related behavior and fear memory were elucidated by a 3 chamber test, a water-finding test and fear conditioning test, respectively. Moreover, the phosphorylation of neuroplasticity-related signaling molecules in mice hippocampus was analyzed using western blotting.

RESULTS

In a therapeutic procedure, YKS ameliorated ISO-induced impairments of attention-like behavior and context-dependent fear memory, but not of sociability, whereas KST had no beneficial effects in ISO mice. In experiments to analyze the preventive/delaying potentials of these treatments, both YKS and KST improved sociability, attention, and context-dependent fear memory deficits. The improvement of sociability in mice by YKS and KST was not inhibited by a dopamine D₁ receptor antagonist, suggesting that YKS and KST improved the ISO-induced sociability deficit by other mechanisms besides activation of the dopaminergic system. On the other hand, the beneficial effects of YKS and KST on attention-like behavior were inhibited by a muscarinic antagonist, suggesting that YKS and KST ameliorated ISO-induced attention-like behavior through a cholinergic mechanism. Moreover, the phosphorylated forms of CaMKII and CREB were down-regulated by ISO stress and restored by YKS and KST administration.

CONCLUSIONS

These findings suggest that YKS and KST may be useful for the improvement of neurodevelopmental disorders.

Combined Memantine and Donepezil Treatment Improves Behavioral and Psychological Symptoms of Dementia-Like Behaviors in Olfactory Bulbectomized Mice

Memantine, an uncompetitive N-methyl-D-aspartate receptor antagonist, and the cholinesterase inhibitor, donepezil, are approved in most countries for treating moderate-to-severe Alzheimer's disease (AD). These drugs have different molecular targets; thus, it is expected that the effects of combined treatment would be synergistic. Some reports do show memantine/donepezil synergy in ameliorating cognition in AD model animals, but their combined effects on behavioral and psychological symptoms of dementia (BPSD)-like behaviors have not been addressed. Here, we investigate combined memantine/donepezil effects on cognitive impairment and BPSD-like behaviors in olfactory bulbectomized (OBX) mice. Interestingly, combined administration synergistically improved both depressive-like behaviors and impaired social interaction in OBX mice, whereas only weak synergistic effects on cognitive performance were seen. To address mechanisms underlying these effects, we used in vivo microdialysis study and observed impaired nicotine-induced serotonin (5-HT) release in OBX mouse hippocampus. Combined memantine/donepezil administration, but not single administration of either, significantly antagonized the decrease in nicotine-induced 5-HT release seen in OBX mouse hippocampus. Furthermore, decreased autophosphorylation of calcium/calmodulin dependent protein kinase II (CaMKII) was rescued in hippocampal CA1 and dentate gyrus of OBX mice by combined memantine/donepezil administration. These results suggest that improvement of BPSD-like behaviors by the co-administration of both drugs is in part mediated by enhanced 5-HT release and CaMKII activity in OBX mouse hippocampus.

Hypothermia-induced ischemic tolerance is associated with Drp1 inhibition in cerebral ischemia-reperfusion injury of mice

Excessive mitochondrial fission activation has been implicated in cerebral ischemia-reperfusion (IR) injury. Hypothermia is effective in preventing cerebral ischemic damage. However, effects of hypothermia on ischemia-induced mitochondrial fission activation is not well known. Therefore, the aim of this study was to investigate whether hypothermia protect the brain by inhibiting mitochondrial fission-related proteins activation following cerebral IR injury. Adult male C57BL/6 mice were subjected to transient forebrain ischemia induced by 15min of bilateral common carotid artery occlusion (BCCAO). Mice were divided into three groups (n=48 each): Hypothermia (HT) group, with mild hypothermia (32-34°C) for 4h; Normothermia (NT) group, similarly as HT group except for cooling; Sham group, with vessels exposed but without occlusion or cooling. Hematoxylin and eosin (HE), Nissl staining, Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and behavioral testing (n=6 each) demonstrated that hypothermia significantly decreased ischemia-induced neuronal injury. The expressions of Dynamin related protein 1 (Drp1) and Cytochrome C (Cyto C) (n=6 each) in mice hippocampus were measured at 3, 6, 24, and 72h of reperfusion. IR injury significantly increased expressions of total Drp1, phosphorylated Drp1 (P-Drp1 S616) and Cyto C under normothermia. However, mild hypothermia inhibited Drp1 activation and Cyto C cytosolic release, preserved neural cells integrity and reduced neuronal necrosis and apoptosis. These findings indicated that mild hypothermia-induced neuroprotective effects against ischemia-reperfusion injury is associated with suppressing mitochondrial fission-related proteins activation and apoptosis execution.

Antiamnesic Effects of a Hydroethanolic Extract of Crinum macowanii on Scopolamine-Induced Memory Impairment in Mice

Crinum macowanii has been found to contain alkaloids that have activity against acetylcholinesterase enzyme in vitro. The present study was undertaken to investigate the in vivo ability of hydroethanolic crude extract of Crinum macowanii to ameliorate memory impairment induced by scopolamine. Thirty-six male Balb/c mice weighing around 25-35 g were employed in the present investigation. Y-maze and novel object recognition apparatus served as the exteroceptive behavioural models, and scopolamine-induced amnesia served as the interoceptive behavioural model. C. macowanii (10, 20, and 40 mg/kg p.o.) was administered in single doses to the mice. Donepezil (3 mg/kg p.o.) was used as a positive control agent. C. macowanii extract reversed the amnesia induced by scopolamine as indicated by a dose-dependent increase in spontaneous alternation performance in the Y-maze task. C. macowanii 40 mg/kg showed significant activity (p < 0.05 versus negative control), comparable to that of the positive control. C. macowanii also showed memory-enhancing activity against scopolamine-induced memory deficits in the long-term memory novel object recognition performance as indicated by a dose-dependent increase in the discrimination index. The results indicate that the hydroethanolic extract of C. macowanii may be a useful memory restorative mediator in the treatment of cognitive disorders such as Alzheimer's disease.

Thunbergia laurifolia extract ameliorates cognitive and emotional deficits in olfactorectomized mice

CONTEXT

Thunbergia laurifolia Lindl. (Acanthaceae) is a Thai medicinal plant used for the detoxification of poison which is likely to be beneficial for the treatment of cognitive deficits including Alzheimer's disease.

OBJECTIVE

To elucidate the effects of Thunbergia laurifolia leaf extract (TLL) on cognitive dysfunction and depression-like behavior in olfactory bulbectomized mice (OBX).

MATERIALS AND METHODS

OBX mice were treated daily with TLL at the dose of 250 and 500 mg/kg, tacrine, and imipramine, on the day after 10 d of OBX operation. The effects of TLL on cognitive and depression-like behavior of the animals were analyzed. After completing behavioral experiments, the expression levels of cholinergic marker genes encoding ChAT and muscarinic M1 receptor were quantitatively analyzed.

RESULTS

TLL and tacrine reduced OBX-induced cognitive deficits in the object recognition test (ORT) with the time spent for the novel object two times longer than that of the familiar object. Moreover, TLL at the dose of 500 mg/kg and imipramine ameliorated depression-like behavior in the tail suspension test (TST) by reducing the duration of immobility from 25.18% to 3.16% and from 25.18% to 6.48%, respectively. TLL at the dose of 250 and 500 mg/kg reversed the OBX-induced down-regulation of ChAT mRNA expression in the hippocampus from 0.12 to 0.17 and 0.24, respectively, while the down-regulation of mRNA expression of muscarinic M1 receptor was also reversed by TLL from 0.23 to 0.38 and 0.48, respectively.

CONCLUSIONS

TLL ameliorates non-spatial short-term memory deficits in OBX mice, and has the potential to exhibit an antidepressant-like action.

Involvement of dopaminergic and cholinergic systems in social isolation-induced deficits in social affiliation and conditional fear memory in mice

Post-weaning social isolation rearing (SI) in rodents elicits various behavioral abnormalities including attention deficit hyperactivity disorder-like behaviors. In order to obtain a better understanding of SI-induced behavioral abnormalities, we herein investigated the effects of SI on social affiliation and conditioned fear memory as well as the neuronal mechanism(s) underlying these effects. Four-week-old male mice were group-housed (GH) or socially isolated for 2-4 weeks before the experiments. The social affiliation test and fear memory conditioning were conducted at the age of 6 and 7 weeks, respectively. SI mice were systemically administered saline or test drugs 30 min before the social affiliation test and fear memory conditioning. Contextual and auditory fear memories were elucidated 1 and 4 days after fear conditioning. Social affiliation and contextual and auditory fear memories were weaker in SI mice than in GH mice. Methylphenidate (MPH), an inhibitor for dopamine transporters, ameliorated the SI-induced social affiliation deficit and the effect was attenuated by SCH23390, a D1 receptor antagonist, but not by sulpiride, a D2 receptor antagonist. On the other hand, tacrine, an acetylcholinesterase inhibitor, had no effect on this deficit. In contrast, tacrine improved SI-induced deficits in fear memories in a manner that was reversed by the muscarinic receptor antagonist scopolamine, while MPH had no effect on memory deficits. Neurochemical studies revealed that SI down-regulated the expression levels of the phosphorylated forms of neuro-signaling proteins, calmodulin-dependent kinase II (p-CaMKII), and cyclic AMP-responsive element binding protein (p-CREB), as well as early growth response protein-1 (Egr-1) in the hippocampus. The administration of MPH or tacrine before fear conditioning had no effect on the levels of the phosphorylated forms of the neuro-signaling proteins elucidated following completion of the auditory fear memory test; however, when analyzed 30 min after the administration of the test drugs, tacrine significantly attenuated the SI-induced decrease in p-CaMKII, p-CREB, and Egr-1 in a manner reversible by scopolamine. Our results suggest that SI-induced deficits in social affiliation and conditioned fear memory were mediated by functional alterations to central dopaminergic and cholinergic systems, respectively.

Protective effects of Bacopa monnieri on ischemia-induced cognitive deficits in mice: the possible contribution of bacopaside I and underlying mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Bacopa monnieri (L.) Wettst. (BM) is a medicinal plant which has been not only used as a traditional medicine to improve intelligence and memory but also taken as vegetables in Vietnam for a long time. We previously demonstrated that Bacopa monnieri (BM) alcohol extract attenuated olfactory bulbectomy-induced cognitive deficits and the deterioration of septo-hippocampal cholinergic neurons, suggesting the beneficial effects of BM for dementia patients.

AIM OF STUDY

The present study was conducted to further clarify the anti-dementia effects of BM, using transient 2 vessels occlusion (T2VO)-induced cognitive deficits in mice, an animal model of vascular dementia, and also to investigate the constituent(s) contributing to the actions of BM, using oxygen- and glucose-deprivation (OGD)-induced hippocampal cell damage as an in vitro model of ischemia.

MATERIALS AND METHODS

In the in vivo experiments, T2VO mice were treated daily with a standardized BM extract (50mg/kg, p.o.) 1 week before and continuously 3 days after surgery. In the in vitro experiments, organotypic hippocampal slice cultures (OHSCs) were incubated with triterpenoid saponins from BM (bacosides) or MK-801 1h before and during a 45-min period of OGD. Neuronal cell damage in OHSCs was analyzed by measurement of propidium iodide uptake 24h after OGD.

RESULTS

The BM treatment significantly ameliorated T2VO-induced impairments in non-spatial short term memory performance in the object recognition test. Among the bacosides tested in the in vitro experiments using OHSCs, bacopaside I (25 μM) exhibited potent neuroprotective effects against OGD-induced neuronal cell damage. Double staining with TUNEL and PI revealed that OGD caused necrosis and apoptosis and that bacopaside I attenuated the effects of OGD. The neuroprotective effects of bacopaside I were blocked by the PKC inhibitor Ro-31-8220 and PI3K inhibitor LY294002, but not by the ERK inhibitor U0126. OGD reduced the level of phospho-Akt (p-Akt), an anti-apoptotic factor, in OHSCs. This decrease was reversed by bacopaside I. Moreover, the treatment with bacopaside I itself was able to elevate the level of p-Akt in OHSCs.

CONCLUSION

These results suggest that BM was beneficial for the prevention of cognitive deficits related to cerebral ischemia and also that bacopaside I, via PKC and PI3K/Akt mechanisms, played a role in the neuroprotective effects of BM observed in the mouse model.

Antidepressant-like effect of Butea superba in mice exposed to chronic mild stress and its possible mechanism of action

ETHNOPHARMACOLOGICAL RELEVANCE

Butea superba (BS) is a Thai medicinal plant that has been used as a folk medicine to improve physical and mental conditions and to prevent impaired sexual performance in middle-aged or elderly males. We have previously reported that this plant extract could improve cognitive deficits and depression-like behavior in olfactory bulbectomized mice, an animal model of dementia and depression.

AIM OF THE STUDY

In this study we examined the effect of BS on depression-like behavior in mice subjected to unpredictable chronic mild stress (UCMS) to clarify the antidepressant-like activity of BS and the molecular mechanism underlying this effect.

MATERIALS AND METHODS

UCMS mice were administered BS daily (300 mg of dried herb weight/kg, p.o.) or a reference drug, imipramine (IMP, 10 mg/kg, i.p.), 1 week after starting the UCMS procedure. We employed the sucrose preference test and the tail suspension test to analyze anhedonia and depression-like behavior of mice, respectively. Serum and brain tissues of mice were used for neurochemical and immunohistochemical studies. The UCMS procedure induced anhedonia and depression-like behavior, and BS treatment, as well as IMP treatment, attenuated these symptoms. UCMS caused an elevation of serum corticosterone level, an index of hyper-activation of the hypothalamic-pituitary-adrenal (HPA) axis, in a manner attenuated by BS and IMP treatment. BS treatment also attenuated UCMS-induced decrease in the expression levels of brain-derived neurotrophic factor (BDNF) mRNA, cyclic AMP-responsive element binding protein (CREB) and a phosphorylated form of N-methyl-d-aspartate receptor subunit NR1, synaptic plasticity-related signaling proteins. Moreover, the UCMS procedure reduced doublecortin-positive cells in the dentate gyrus region of the hippocampus. BS administration reversed these UCMS-induced neurochemical and histological abnormalities.

CONCLUSION

These results suggest that BS can ameliorate chronic stress-induced depression-like symptoms and that the effects of BS are mediated by restoring dysfunctions of the HPA axis and synaptic plasticity-related signaling systems and neurogenesis in the hippocampus.

Mother/offspring co-administration of the traditional herbal remedy yokukansan during the nursing period influences grooming and cerebellar serotonin levels in a rat model of neurodevelopmental disorders

Neurodevelopmental impairment in the serotonergic system may be involved in autism spectrum disorder. Yokukansan is a traditional herbal remedy for restlessness and agitation in children, and mother-infant co-administration (MICA) to both the child and the nursing mother is one of the recommended treatment approaches. Recent studies have revealed the neuropharmacological properties of Yokukansan (YKS), including its 5-HT1A (serotonin) receptor agonistic effects. We investigated the influence of YKS treatment on behavior in a novel environment and on brain monoamine metabolism during the nursing period in an animal model of neurodevelopmental disorders, prenatally BrdU (5-bromo-2'-deoxyuridine)-treated rats (BrdU-rats). YKS treatment did not influence locomotor activity in BrdU-rats but reduced grooming in open-field tests. YKS treatment without MICA disrupted the correlation between locomotor behaviors and rearing and altered levels of serotonin and its metabolite in the cerebellum. These effects were not observed in the group receiving YKS treatment with MICA. These data indicate a direct pharmacological effect of YKS on the development of grooming behavior and profound effects on cerebellar serotonin metabolism, which is thought to be influenced by nursing conditions.

Yokukan-san: a review of the evidence for use of this Kampo herbal formula in dementia and psychiatric conditions

Japanese traditional herbal medicine (Kampo) has its origins in traditional Chinese medicine (TCM). It was introduced to Japan in the middle of the sixth century and has evolved over the past 1,400 years after combining with Japan's original folk remedies. While it retains some similarities to TCM, Kampo has evolved in Japan, resulting in a system of medicine that has many differences from TCM. Kampo medicine is considered to be very safe; in Japan, Kampo herbal formulas are manufactured by licensed pharmaceutical companies, prescribed by Western-trained medical doctors (usually as a freeze-dried extract), and have quality control standards similar to those of prescription drugs. The present study examined Yokukan-san (Yi-Gan San in TCM), a Kampo formula that has been used empirically in Japan for more than 400 years. Accumulating clinical trials have demonstrated Yokukan-san's efficacy in treating patients with behavioral and psychological symptoms of dementia, which has resulted in the Japanese Society of Neurology listing it in the Japanese Guidelines for the Management of Dementia 2010. Efficacy in other diseases and conditions, such as sleep disorders, tardive dyskinesia, aggression, and impulsivity has also been reported. This article reviews both clinical and basic studies of Yokukan-san, with the goal of clarifying its clinical indications.

Social isolation stress-induced fear memory deficit is mediated by down-regulated neuro-signaling system and Egr-1 expression in the brain

We previously reported that social isolation (SI) rearing of rodents not only elicits a variety of behavioral abnormalities including attention deficit hyperactivity disorder-like behaviors, but also impairs fear memory in mice. This study aimed to clarify a putative mechanism underlying SI-induced conditioned fear memory deficit. Mice were group-housed (GH) or socially isolated for 2 weeks or more before the experiments. SI animals acquired contextual and auditory fear memory elucidated at 90 min and 4 h after training, respectively; however, they showed significantly impaired contextual and auditory memory performance at 24 h and 4 days after the training, respectively, indicating SI-induced deficit of the consolidation process of fear memory. Neurochemical studies conducted after behavioral tests revealed that SI mice had a significantly down-regulated level of Egr-1 but not Egr-2 in the hippocampal and cortical cytosolic fractions compared with those levels in the GH control animals. Moreover, in the SI group, phosphorylated levels of synaptic plasticity-related signaling proteins in the hippocampus, NR1 subunit of N-methyl-D-aspartate receptor, glutamate receptor 1, and calmodulin-dependent kinase II but not cyclic AMP-responsive element binding protein were significantly down-regulated compared with those levels in GH animals, whereas non-phosphorylated levels of these proteins were not affected by SI. These findings suggest that dysfunctions of Egr-1 and neuro-signaling systems are involved in SI-induced deficits of fear memory consolidation in mice.

Butea superba-induced amelioration of cognitive and emotional deficits in olfactory bulbectomized mice and putative mechanisms underlying its actions

This study investigated the effects of alcoholic extract of Butea superba (BS) on cognitive deficits and depression-related behavior using olfactory bulbectomized (OBX) mice and the underlying molecular mechanisms of its actions. OBX mice were treated daily with BS (100 and 300 mg/kg, p.o.) or reference drugs, tacrine (2.5 mg/kg, i.p.) and imipramine (10 mg/kg, i.p.) from day 3 after OBX. OBX impaired non-spatial and spatial cognitive performances, which were elucidated by the novel object recognition test and modified Y maze test, respectively. These deficits were attenuated by tacrine and BS but not imipramine. OBX animals exhibited depression-like behavior in the tail suspension test in a manner reversible by imipramine and BS but not tacrine. OBX down-regulated phosphorylation of synaptic plasticity-related signaling proteins: NMDA receptor, AMPA receptor, calmodulin-dependent kinase II, and cyclic AMP-responsive element-binding protein. OBX also reduced choline acetyltransferase in the hippocampus. BS and tacrine reversed these neurochemical alterations. Moreover, BS inhibited ex vivo activity of acetylcholinesterase in the brain. These results indicate that BS ameliorates not only cognition dysfunction via normalizing synaptic plasticity-related signaling and facilitating central cholinergic systems but also depression-like behavior via a mechanism differing from that implicated in BS amelioration of cognitive function in OBX animals.

Inosine improves functional recovery after experimental traumatic brain injury

Despite years of research, no effective therapy is yet available for the treatment of traumatic brain injury (TBI). The most prevalent and debilitating features in survivors of TBI are cognitive deficits and motor dysfunction. A potential therapeutic method for improving the function of patients following TBI would be to restore, at least in part, plasticity to the CNS in a controlled way that would allow for the formation of compensatory circuits. Inosine, a naturally occurring purine nucleoside, has been shown to promote axon collateral growth in the corticospinal tract (CST) following stroke and focal TBI. In the present study, we investigated the effects of inosine on motor and cognitive deficits, CST sprouting, and expression of synaptic proteins in an experimental model of closed head injury (CHI). Treatment with inosine (100 mg/kg i.p. at 1, 24 and 48 h following CHI) improved outcome after TBI, significantly decreasing the neurological severity score (NSS, p<0.04 vs. saline), an aggregate measure of performance on several tasks. It improved non-spatial cognitive performance (object recognition, p<0.016 vs. saline) but had little effect on sensorimotor coordination (rotarod) and spatial cognitive functions (Y-maze). Inosine did not affect CST sprouting in the lumbar spinal cord but did restore levels of the growth-associated protein GAP-43 in the hippocampus, though not in the cerebral cortex. Our results suggest that inosine may improve functional outcome after TBI.

Brain region-specific reduction in c-Fos expression associated with an anxiolytic effect of yokukansan in rats

ETHNOPHARMACOLOGICAL RELEVANCE

A traditional Japanese (Kampo) medicine, yokukansan, has long been used to treat neurosis, insomnia, and night crying and irritability in children. Recently, this medicine has reported to improve the behavioral and psychological symptoms of dementia that often become problematic in patients with Alzheimer's disease and other forms of dementia.

AIM OF THE STUDY

Several animal studies have reported that yokukansan has an anxiolytic effect. However, the underlying mechanisms are not yet understood. In the present study, we investigated the effects in rats of single and repeated administrations of yokukansan on anxiety-like behaviors, stress responses, and the brain regions involved.

MATERIALS AND METHODS

Yokukansan dissolved in water (100 or 300 mg/kg) was administered orally to F344/N male rats 1h before each test or for two weeks before the tests began. Locomotor activity and anxiety-related behavior in the open-field test and the elevated plus-maze test, serum corticosterone levels, and restraint stress-induced c-Fos expression in various brain regions as a marker of neuronal activation were evaluated in both the vehicle-treated and yokukansan-treated rats.

RESULTS

A single administration of yokukansan had no effect on locomotor activity or anxiety-like behavior; however, repeated administration decreased anxiety-like behavior in a dose-dependent manner. Neither single nor repeated administration of yokukansan had an effect on the basal or stress-induced levels of serum corticosterone. For c-Fos expression, restraint stress increased the number of c-Fos-positive cells in the subdivisions of the prefrontal cortex, amygdala, and hypothalamus. Repeated administration of yokukansan decreased the stress-induced c-Fos expression in the prelimbic cortex and the basolateral and medial amygdaloid nuclei.

CONCLUSIONS

The present study indicates that repeated oral administration of yokukansan has an anxiolytic effect and that this effect may be associated with attenuated neuronal activity in the medial prefrontal cortex and amygdala.

Bacopa monnieri ameliorates memory deficits in olfactory bulbectomized mice: possible involvement of glutamatergic and cholinergic systems

This study investigated the effects of alcoholic extract of Bacopa monnieri (L.) Wettst. (BM) on cognitive deficits using olfactory bulbectomized (OBX) mice and the underlying molecular mechanisms of its action. OBX mice were treated daily with BM (50 mg/kg, p.o.) or a reference drug, tacrine (2.5 mg/kg, i.p.), 1 week before and continuously 3 days after OBX. Cognitive performance of the animals was analyzed by the novel object recognition test, modified Y maze test, and fear conditioning test. Brain tissues of OBX animals were used for neurochemical and immunohistochemical studies. OBX impaired non-spatial short-term memory, spatial working memory, and long-term fair memory. BM administration ameliorated these memory disturbances. The effect of BM on short-term memory deficits was abolished by a muscarinic receptor antagonist, scopolamine. OBX downregulated phosphorylation of synaptic plasticity-related signaling proteins: NR1 subunit of N-methyl-D-aspartate receptor, glutamate receptor 1 (GluR1), and calmodulin-dependent kinase II but not cyclic AMP-responsive element binding protein (CREB), and reduced brain-derived neurotrophic factor (BDNF) mRNA in the hippocampus. OBX also reduced choline acetyltransferase in the hippocampus and cholinergic neurons in the medial septum, and enlarged the size of lateral ventricle. BM administration reversed these OBX-induced neurochemical and histological alterations, except the decrease of GluR1 phosphorylation, and enhanced CREB phosphorylation. Moreover, BM treatment inhibited ex vivo activity of acetylcholinesterase in the brain. These results indicate that BM treatment ameliorates OBX-induced cognition dysfunction via a mechanism involving enhancement of synaptic plasticity-related signaling and BDNF transcription and protection of cholinergic systems from OBX-induced neuronal damage.

Kampo formulations, chotosan, and yokukansan, for dementia therapy: existing clinical and preclinical evidence

Cognitive deficits and behavioral and psychological symptoms of dementia (BPSD) are typical features of patients with dementia such as Alzheimer's disease (AD), vascular dementia (VD), and other forms of senile dementia. Clinical evidence has demonstrated the potential usefulness of chotosan (CTS) and yokukansan (YKS), traditional herbal formulations called Kampo medicines, in the treatment of cognitive disturbance and BPSD in dementia patients, although the indications targeted by CTS and YKS in Kampo medicine differ. The availability of CTS and YKS for treating dementia patients is supported by preclinical studies using animal models of dementia that include cognitive/emotional deficits caused by aging and diabetes, dementia risk factors. These studies have led not only to the concept of a neuronal basis for the CTS- and YKS-induced amelioration of cognitive function and emotional/psychiatric symptom-related behavior in animal models, but also to a proposal that ingredient(s) of Uncariae Uncis cum Ramulus, a medicinal herb included in CTS and YKS, may play an important role in the actions of these formulae in dementia patients. Further studies are needed to clarify the active ingredients of these formulae and their target endogenous molecules implicated in the anti-dementia drug-like actions.

Ameliorative Effects of Acanthopanax trifoliatus on Cognitive and Emotional Deficits in Olfactory Bulbectomized Mice: An Animal Model of Depression and Cognitive Deficits

Acanthopanax trifoliatus is a plant that has been traditionally used in Thailand as a vegetable and a tonic. This study investigated effects of the aqueous extract of its leaves (ATL) on cognitive and emotional deficits using an olfactory bulbectomized mouse (OBX) model. OBX mice were treated daily with ATL (250 and 500 mg/kg, p.o.) 3 days after OBX. Antidementia drug tacrine (2.5 mg/kg/day) and antidepressant drug imipramine (10 mg/kg/day) were given i.p. as reference drugs. OBX significantly impaired cognitive behavior in a novel object recognition test and a modified Y-maze test and induced depression-like behavior in a tail suspension test. ATL and tacrine treatment attenuated OBX-induced cognitive deficits, whereas ATL and imipramine improved OBX-induced depression-like behavior. Neurochemical studies conducted after completing behavioral experiments demonstrated that OBX downregulated the expression levels of cholinergic marker genes encoding choline acetyltransferase and muscarinic M₁ receptor in a manner reversed by ATL and tacrine. Moreover, ATL and tacrine administration inhibited the ex vivo activity of acetylcholinesterase in the brain. These findings suggest that ATL is beneficial for the treatment of cognitive and emotional deficits related to dementia with depressive symptoms and that the antidementia effect of ATL is mediated by normalizing the function of central cholinergic systems.

Social isolation induces deficit of latent learning performance in mice: a putative animal model of attention deficit/hyperactivity disorder

Social isolation of rodents (SI) elicits a variety of stress responses such as increased aggressiveness, hyper-locomotion, and reduced susceptibility to pentobarbital. To obtain a better understanding of the relevance of SI-induced behavioral abnormalities to psychiatric disorders, we examined the effect of SI on latent learning as an index of spatial attention, and discussed the availability of SI as an epigenetic model of attention deficit hyperactivity disorder (ADHD). Except in specially stated cases, 4-week-old male mice were housed in a group or socially isolated for 3-70 days before experiments. The animals socially isolated for 1 week or more exhibited spatial attention deficit in the water-finding test. Re-socialized rearing for 5 weeks after 1-week SI failed to attenuate the spatial attention deficit. The effect of SI on spatial attention showed no gender difference or correlation with increased aggressive behavior. Moreover, SI had no effect on cognitive performance elucidated in a modified Y-maze or an object recognition test, but it significantly impaired contextual and conditional fear memory elucidated in the fear-conditioning test. Drugs used for ADHD therapy, methylphenidate (1-10 mg/kg, i.p.) and caffeine (0.5-1 mg/kg, i.p.), improved SI-induced latent learning deficit in a manner reversible with cholinergic but not dopaminergic antagonists. Considering the behavioral features of SI mice together with their susceptibility to ADHD drugs, the present findings suggest that SI provides an epigenetic animal model of ADHD and that central cholinergic systems play a role in the effect of methylphenidate on SI-induced spatial attention deficit.

Chotosan ameliorates cognitive and emotional deficits in an animal model of type 2 diabetes: possible involvement of cholinergic and VEGF/PDGF mechanisms in the brain

BACKGROUND

Diabetes is one of the risk factors for cognitive deficits such as Alzheimer's disease. To obtain a better understanding of the anti-dementia effect of chotosan (CTS), a Kampo formula, we investigated its effects on cognitive and emotional deficits of type 2 diabetic db/db mice and putative mechanism(s) underlying the effects.

METHODS

Seven-week-old db/db mice received daily administration of CTS (375 - 750 mg/kg, p.o.) and the reference drug tacrine (THA: 2.5 mg/kg, i.p.) during an experimental period of 7 weeks. From the age of 9-week-old, the animals underwent the novel object recognition test, the modified Y-maze test, and the water maze test to elucidate cognitive performance and the elevated plus maze test to elucidate anxiety-related behavior. After completing behavioral studies, Western blotting and immunohistochemical studies were conducted.

RESULTS

Compared with age-matched non-diabetic control strain (m/m) mice, db/db mice exhibited impaired cognitive performance and an increased level of anxiety. CTS ameliorated cognitive and emotional deficits of db/db mice, whereas THA improved only cognitive performance. The phosphorylated levels of Akt and PKCα in the hippocampus were significantly lower and higher, respectively, in db/db mice than in m/m mice. Expression levels of the hippocampal cholinergic marker proteins and the number of the septal cholinergic neurons were also reduced in db/db mice compared with those in m/m mice. Moreover, the db/db mice had significantly reduced levels of vasculogenesis/angiogenesis factors, vascular endothelial growth factor (VEGF), VEGF receptor type 2, platelet-derived growth factor-B, and PDGF receptor β, in the hippocampus. CTS and THA treatment reversed these neurochemical and histological alterations caused by diabetes.

CONCLUSION

These results suggest that CTS ameliorates diabetes-induced cognitive deficits by protecting central cholinergic and VEGF/PDGF systems via Akt signaling pathway and that CTS exhibits the anxiolytic effect via neuronal mechanism(s) independent of cholinergic or VEGF/PDGF systems in db/db mice.

Yokukansan inhibits morphine tolerance and physical dependence in mice: the role of α₂A-adrenoceptor

Yokukansan (YKS) is a traditional Japanese medicine consisting of seven medicinal herbs that is used for the treatment of neurosis, insomnia, and the behavioral/psychological symptoms of dementia. This study examined the effects of YKS on morphine tolerance and physical dependence in mice. Daily oral administration of YKS (0.5 or 1.0 g/kg) for 3 weeks significantly attenuated morphine tolerance and naloxone-precipitated morphine withdrawal signs (jumps and body weight loss) without affecting the analgesic effect of morphine. The inhibitory effect of YKS on withdrawal jumps in morphine-dependent mice was blocked by a single pretreatment with an α(2)-adrenoceptor antagonist, yohimbine, but not by an α(1)-adrenoceptor antagonist, prazosin. A similar inhibitory effect on withdrawal jumps was observed by repeated administration of yohimbine. The membrane expression of α(2A)-adrenoceptors in the pons/medulla was decreased in morphine withdrawn animals; this reduction was prevented by repeated administration of YKS or yohimbine. Competitive radioligand and [(35)S]guanosine-5'-O-(3-thiotriphosphate) binding assays revealed that YKS and its constituent herbs, Glycyrrhiza (GR) and Uncaria hook (UH), had specific binding affinity for and antagonist activity against the α(2A)-adrenoceptor. Certain chemical constituents, including GR -derived glycyrrhizin and its metabolite, 18β-glycyrrhetinic acid, and UH-derived geissoschizine methyl ether (GME), shared such activities. Repeated administration of GR, UH, glycyrrhizin or GME significantly inhibited morphine withdrawal signs. These results suggest that YKS and its active constituents inhibit morphine tolerance and physical dependence, and that the latter is due at least in part to the prevention of the decreased membrane expression of the α(2A)-adrenoceptor in the brainstem by its prolonged blockade.

Anxiolytic effects of yokukansan, a traditional Japanese medicine, via serotonin 5-HT1A receptors on anxiety-related behaviors in rats experienced aversive stress

ETHNOPHARMACOLOGICAL RELEVANCE

Yokukansan, a traditional Japanese medicine (Kampo), has been reported in the treatment of behavioral and psychological symptoms of dementia (BPSD) such as aggression, anxiety and depression in patients with Alzheimer's disease and other forms of senile dementia.

AIMS OF THE STUDY

In the present study, we investigated the anxiolytic effects of yokukansan on anxiety-related behaviors in rats that have experienced aversive stress.

MATERIALS AND METHODS

We used male Wistar/ST rats which received an electrical footshock as aversive stress. Yokukansan at a dose of 1.0 g/kg was administered orally once a day for 14 or 16 day before behavioral tests. To evaluate the anxiolytic effects, we used the contextual fear conditioning (CFC) test and elevated plus-maze (EPM) test. And we also investigated effects of yokukansan on locomotor activity in the Open-field (OF) test and on the change in plasma corticosterone after CFC stress, in rats that had experienced footshock stress.

RESULTS

In the CFC test, rats that had experienced footshock showed significant freezing behavior on re-exposure to the box 14 day after footshock stress. Yokukansan significantly suppressed freezing behavior in the CFC test. In the EPM test on the 16th day after the CFC test, yokukansan significantly increased the time spent in open arms after footshock stress compared to control rats. However, repeated administration of yokukansan on the 14th day did not affect the decrease in locomotor activity and the increase in plasma corticosterone by re-exposure to the box 14 day after footshock stress in the OF test and determination of serum corticosterone, respectively. These anxiolytic effects by yokukansan were antagonized by WAY-100635, a selective 5-HT(1A) receptor antagonist, in the CFC test, but not the EPM test. Furthermore, 5-HT(1A) receptor agonist buspirone significantly suppressed freezing behavior in the CFC test; however, buspirone induced no change in the time spent in open arms in the EPM test.

CONCLUSION

These findings suggested that yokukansan has anxiolytic effects on anxiety-like behaviors induced by both innate fear and memory-dependent fear. In particular, yokukansan produced anxiolytic effects via 5-HT(1A) receptors in memory-dependent fear induced by aversive stress. Furthermore, yokukansan could be useful as one of the therapeutic drugs for the treatment of anxiety disorders and various mental disorders that have comorbid anxiety.

Fluoxetine reverses depressive-like behaviors and increases hippocampal acetylcholinesterase activity induced by olfactory bulbectomy

The olfactory bulbectomy (OB) is an animal model of depression that results in behavioral, neurochemical and neuroendocrinological changes, features comparable to those seen in depressive patients. This study investigated OB-induced alterations in locomotor activity and exploratory behavior in the open-field test, self-care and motivational behavior in the splash test, hyperactivity in the novel object test and novel cage test, and the influence of chronic treatment with fluoxetine (10mg/kg, p.o., once daily for 14days) on these parameters. Fluoxetine reversed OB-induced hyperactivity in the open-field test, locomotor hyperactivity and the increase in exploratory behavior induced by novelty in the novel object and novel cage tests, and the loss of self-care and motivational behavior in the splash test. Moreover, OB decreased the number of grooming and fecal boli in the open-field and novel cage tests, alterations that were not reversed by fluoxetine. OB caused an increase in hippocampal, but not in prefrontal acetylcholinesterase (AChE) activity. Fluoxetine was able to reverse the increase in hippocampal AChE activity induced by OB. Serum corticosterone was increased in SHAM and bulbectomized mice treated with fluoxetine. In conclusion, OB mice exhibited depressive-like behaviors associated with an increase in hippocampal AChE activity, effects that were reversed by chronic treatment with fluoxetine.

Rosmarinus officinalis L. hydroalcoholic extract, similar to fluoxetine, reverses depressive-like behavior without altering learning deficit in olfactory bulbectomized mice

ETHNOPHARMACOLOGICAL RELEVANCE

Rosemary, Rosmarinus officinalis L., has several therapeutic applications in folk medicine for the treatment of a wide range of diseases, including depression.

AIM OF THE STUDY

To evaluate the ability of Rosmarinus officinalis hydroalcoholic extract (ROHE), as compared to the positive control fluoxetine, to reverse behavioral (hyperactivity, anhedonic behavior and learning deficit in water maze) and biochemical alterations (serum glucose level and acetylcholinesterase, AChE, activity) induced by an animal model of depression, the olfactory bulbectomy (OB) in mice.

MATERIALS AND METHODS

Locomotor and exploratory behavior was assessed in the open-field, novel object and novel cage tests, anhedonic behavior was assessed in the splash test; cognitive deficits were evaluated in the water maze task. For the first set of experiments, ROHE (10-300 mg/kg) or fluoxetine (10mg/kg) was administered once daily (p.o.) for 14 days after OB and the behavioral tests were performed. For the second set of experiments, serum glucose and hippocampal and cerebrocortical AChE activity were determined in OB and SHAM-operated mice treated orally with ROHE (10mg/kg), fluoxetine (10mg/kg) or vehicle.

RESULTS

ROHE (10-300 mg/kg), similar to fluoxetine, reversed OB-induced hyperactivity, increased exploratory and anhedonic behavior. OB needed significantly more trials in the training session to acquire the spatial information, but they displayed a similar profile to that of SHAM mice in the test session (24h later), demonstrating a selective deficit in spatial learning, which was not reversed by ROHE or fluoxetine. A reduced serum glucose level and an increased hippocampal AChE activity were observed in bulbectomized mice; only the latter effect was reversed by fluoxetine, while both effects were reversed by ROHE.

CONCLUSIONS

ROHE exerted an antidepressant-like effect in bulbectomized mice and was able to abolish AchE alterations and hypoglycemia, but not spatial learning deficit induced by OB. Overall, results suggest the potential of Rosmarinus officinalis for the treatment of depression, validating the traditional use of this plant.

Behavioral animal models to assess pro-cognitive treatments for schizophrenia

Cognitive dysfunction is a core aspect of schizophrenia that constitutes a major obstacle toward reintegration of patients into society. Although multiple cognitive deficits are evident in schizophrenia patients, no medication is currently approved for their amelioration. Although consensus clinical test batteries have been developed for the assessment of putative cognition enhancers in patients with schizophrenia, parallel animal tests remain to be validated. Having no approved treatment for cognitive symptoms means no positive control can be used to examine pharmacological predictive validity of animal models. Thus, focus has been placed on animal paradigms that have demonstrable construct validity for the cognitive domain being assessed.This review describes the growing arsenal of animal paradigms under development that have putative construct validity to cognitive domains affected in schizophrenia. We discuss (1) the construct validity of the paradigms; (2) compounds developed to investigate putative treatment targets; and (3) manipulations used to first impair task performance. Focus is placed on the paradigm design, including how the use of multivariate assessments can provide evidence that main effects of treatment are not confounded by extraneous effects.

Diabetes-induced central cholinergic neuronal loss and cognitive deficit are attenuated by tacrine and a Chinese herbal prescription, kangen-karyu: elucidation in type 2 diabetes db/db mice

We investigated the effect of kangen-karyu (KK), a Chinese herbal prescription, on cognitive deficits and central cholinergic systems of type 2 diabetic db/db mice. Seven-week-old db/db (Y-db/db) mice received daily administration of test drugs during an experimental period of 12 weeks. At 18 weeks of age (O-db/db), the animals underwent the water maze test. Compared with age-matched control strain mice (O-m/m), vehicle-treated O-db/db mice showed impaired learning and memory performance. KK (100 - 200 mg/kg per day) and the reference drug tacrine (THA: 2.5 mg/kg per day) ameliorated the performance of O-db/db mice without affecting their serum glucose level. O-db/db mice had lower levels of brain-derived neurotrophic factor (BDNF) mRNA and its protein in the brain than O-m/m mice. Expression levels of central cholinergic marker proteins in the hippocampus and the number of cholinergic cells in the medial septum and basal forebrain were also significantly lower in O-db/db than in O-m/m mice, whereas no significant differences in the expression levels of these factors and the cell number were found between Y-m/m and Y-db/db mice. KK and THA treatment significantly reversed the down-regulated levels of cholinergic markers, choline acetyltransferase-positive cell number, and BDNF expression in db/db mice. These findings suggest that KK as well as THA prevents diabetes-induced cognitive deficits by attenuating dysfunction of central cholinergic systems.

Chotosan (Diaoteng San)-induced improvement of cognitive deficits in senescence-accelerated mouse (SAMP8) involves the amelioration of angiogenic/neurotrophic factors and neuroplasticity systems in the brain

Background

Chotosan (CTS, Diaoteng San), a Kampo medicine (ie Chinese medicine) formula, is reportedly effective in the treatment of patients with cerebral ischemic insults. This study aims to evaluate the therapeutic potential of CTS in cognitive deficits and investigates the effects and molecular mechanism(s) of CTS on learning and memory deficits and emotional abnormality in an animal aging model, namely 20-week-old senescence-accelerated prone mice (SAMP8), with and without a transient ischemic insult (T2VO).

Methods

Age-matched senescence-resistant inbred strain mice (SAMR1) were used as control. SAMP8 received T2VO (T2VO-SAMP8) or sham operation (sham-SAMP8) at day 0. These SAMP8 groups were administered CTS (750 mg/kg, p.o.) or water daily for three weeks from day 3.

Results

Compared with the control group, both sham-SAMP8 and T2VO-SAMP8 groups exhibited cognitive deficits in the object discrimination and water maze tests and emotional abnormality in the elevated plus maze test. T2VO significantly exacerbated spatial cognitive deficits of SAMP8 elucidated by the water maze test. CTS administration ameliorated the cognitive deficits and emotional abnormality of sham- and T2VO-SAMP8 groups. Western blotting and immunohistochemical studies revealed a marked decrease in the levels of phosphorylated forms of neuroplasticity-related proteins, N-methyl-D-aspartate receptor 1 (NMDAR1), Ca²⁺/calmodulin-dependent protein kinase II (CaMKII), cyclic AMP responsive element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in the frontal cortices of sham-SAMP8 and T2VO-SAMP8. Moreover, these animal groups showed significantly reduced levels of vasculogenesis/angiogenesis factors, vascular endothelial growth factor (VEGF), VEGF receptor type 2 (VEGFR2), platelet-derived growth factor-A (PDGF-A) and PDGF receptor α (PDGFRα). CTS treatment reversed the expression levels of these factors down-regulated in the brains of sham- and T2VO-SAMP8.

Conclusion

Recovery of impaired neuroplasticity system and VEGF/PDGF systems may play a role in the ameliorative effects of CTS on cognitive dysfunction caused by aging and ischemic insult.