Scopolamine Induced Amnesia is Reversed by Bacopa monniera Through Participation of Kinase-CREB Pathway

Metabolomics study to reveal cognitive improvement with treatment of Scrophularia buergeriana

Population aging around the world is rapidly progressing; as a result, cognitive decline developing into dementia is becoming a social problem. There is no drug that can cure dementia, and though drugs that alleviate the symptoms of dementia have been developed, they also have side effects. Therefore, we conducted a study on improving cognitive function using natural products that have secured safety. We confirmed the effect of an extract of Scrophularia buergeriana on scopolamine-induced cognitive impairment through mouse behavioral experiments, and we observed metabolic changes in the cortex and hippocampus via brain tissue dissection after the behavioral experiment. Mitigating effects of S. buergeriana on cognitive impairment caused by scopolamine were observed in passive avoidance and Morris water maze tests. A metabolic analysis revealed biomarkers related to the alleviating effect of cognitive impairment. Niacinamide, tyrosine, uridine, and valine in the cortex and GABA, choline, creatine, formate, fumarate, hypoxanthine, leucine, myo-inositol, pyroglutamate, and taurine in the hippocampus were identified as biomarker candidates for recovering cognitive impairment. In addition to behavioral experiments, this metabolomics study using specific regions of the brain may be helpful in understanding the effects of cognitive improvement.

Neuroprotection by Polyherbal Medicine Divya-Medha-Vati Against Scopolamine-Induced Cognitive Impairment Through Modulation of Oxidative Stress, Acetylcholine Activity, and Cell Signaling

Alzheimer disease is associated with cognitive impairments and neuronal damages. In this study, Scopolamine, a model drug used for the generation of Alzheimer-like symptoms induced cognitive dysfunction in C57BL/6 mice. It also elevated acetylcholine esterase (AcHE) activity, and reduced antioxidant (superoxide dismutase and catalase) activity in cortex tissue. Scop reduced neuronal density and increased pyknotic neurons in hippocampus tissue. In mouse neuroblastoma (Neuro2a) cells, Scop triggered a dose-dependent loss of cell viability and neurite outgrowth reduction. Scop-treated Neuro2a cells showed oxidative stress and reduction in mRNA expression for brain-derived neurotrophic factor (BDNF), nerve growth factor-1 (NGF-1), and Synapsin-1 (SYN-1) genes. Mice treated with Divya-Medha-Vati (DMV), an Ayurvedic polyherbal medicine showed protection against Scop-induced cognitive impairment (Morris Water Maze Escape Latency, and Elevated Plus Maze Transfer Latency). DMV protected against Scop-induced AcHE activity, and loss of antioxidant activities in the mice brain cortex while sustaining neuronal density in the hippocampus region. In the Neuro2a cells, DMV reduced Scop-induced loss of cell viability and neurite outgrowth loss. DMV protected the cells against induction of oxidative stress and promoted mRNA expression of BDNF, NGF-1, and SYN-1 genes. Phytochemical profiling of DMV showed the presence of Withanolide A, Withanolide B, Bacopaside II, Jujubogenin, Apigenin, Gallic acid, Caffeic acid, and Quercetin that are associated with antioxidant and neurostimulatory activities. In conclusion, the study showed that Divya-Medha-Vati was capable of promoting neuronal health and inhibiting Alzheimer-like cognitive dysfunction through enhanced antioxidant activities and modulation of neuronal activities.

Combinatory Approaches Targeting Cognitive Impairments and Memory Enhancement: A Review

The objective of this paper is to look at how natural medicines can improve cognition and memory when used with sildenafil, a popular erectile dysfunction medicine that also has nootropic properties. Newer treatment strategies to treat the early stages of these diseases need to be developed. Multiple factors lead to complex pathophysiological conditions, which are responsible for various long-term complications. In this review, a combination of treatments targeting these pathologies is discussed. These combinations may help manage early and later phases of cognitive impairments. The purpose of this article is to discuss a link between these pathologies and a combinational approach with the objective of considering newer therapeutic strategies in the treatment of cognitive impairments. The natural drugs and their ingredients play a major role in the management of disease progression. Additionally, their combination with sildenafil allows for more efficacy and better response. Studies showing the effectiveness of natural drugs and sildenafil are mentioned, and how these combinations could be beneficial for the treatment of cognitive impairments and amnesia are summarised. Furthermore, preclinical and clinical trials are required to explore the medicinal potential of these drug combinations.

Bacosides from Bacopa monnieri extract: An overview of the effects on neurological disorders

From ancient history, complementary and alternative medicines have played a significant role as holistic therapeutic treatments of various human diseases including cancer, diabetes, neurological diseases, and skin problems. One Indian medicinal plant (herb), Bacopa monnieri has been used in many parts of the world as such medicine, particularly for the treatment of various neurological disorders. It is well known as a potent "tonic for the human brain," which serves as a memory enhancer. Multiple studies proved that this herb contains a plethora of potential bioactive, phytochemical compounds with synergistic properties. The main purpose of the present review is to shed light on the use of Bacopa monnieri and its active principles (bacosides) in the management of neurological disorders. Furthermore, the signaling pathways modulated by bacosides have been critically discussed in this review. Moreover, we have critically summarized the present knowledge of this perennial creeping herb based upon the literature mining from different scientific engines.

Volume Analysis of Brain Cognitive Areas in Alzheimer's Disease: Interim 3-Year Results from the ASCOMALVA Trial

Background:

Cerebral atrophy is a common feature of several neurodegenerative disorders, including Alzheimer’s disease (AD). In AD, brain atrophy is associated with loss of gyri and sulci in the temporal and parietal lobes, and in parts of the frontal cortex and cingulate gyrus.

Objective:

The ASCOMALVA trial has assessed, in addition to neuropsychological analysis, whether the addition of the cholinergic precursor choline alphoscerate to treatment with donepezil has an effect on brain volume loss in patients affected by AD associated with cerebrovascular injury.

Methods:

56 participants to the randomized, placebo-controlled, double-blind ASCOMALVA trial were assigned to donepezil + placebo (D + P) or donepezil + choline alphoscerate (D + CA) treatments and underwent brain magnetic resonance imaging and neuropsychological tests every year for 4 years. An interim analysis of 3-year MRI data was performed by voxel morphometry techniques.

Results:

The D + P group (n = 27) developed atrophy of the gray and white matter with concomitant increase in ventricular space volume. In the D + CA group (n = 29) the gray matter atrophy was less pronounced compared to the D + P group in frontal and temporal lobes, hippocampus, and amygdala. These morphological data are consistent with the results of the neuropsychological tests.

Conclusion:

Our findings indicate that the addition of choline alphoscerate to standard treatment with the cholinesterase inhibitor donepezil counters to some extent the loss in volume occurring in some brain areas of AD patients. The observation of parallel less pronounced decrease in cognitive and functional tests in patients with the same treatment suggests that the morphological changes observed may have functional relevance.

The Neurocognitive Effects of Bacopa monnieri and Cognitive Training on Markers of Brain Microstructure in Healthy Older Adults

Bacopa monnieri (BM) is a herbal supplement that increases signaling molecules implicated in synaptogenesis. Combined with cognitive stimulation, it may be a viable supplement to enhance long-term potentiation (LTP) and improve cognitive health in older adults. This randomized, double-blind, placebo-controlled trial asked 28 healthy adults aged over 55 years to complete cognitive training (CT) 3 hours weekly for 12 weeks. Fifteen consumed a standardized extract of BM and 13 consumed a placebo daily. Cognitive tasks, life-satisfaction, memory complaints and mood were assessed, and bloods analyzed for serum brain-derived neurotrophic factor (BDNF) before and after 12-weeks of the intervention. Diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) in gray (GM) and white matter (WM) were also analyzed. Results demonstrated slower reaction time in an image discrimination task in the BM group and faster reaction time in a spatial working memory task (SWM-O RT) in the placebo group. Mean accuracy was higher in the BM group for these tasks, suggesting a change in the speed accuracy trade-off. Exploratory neuroimaging analysis showed increased WM mean diffusivity (MD) and GM dispersion of neurites (orientation dispersion index, ODI) and decreased WM fractional anisotropy (FA) and GM neurite density (ND) in the BM group. No other outcomes reached statistical significance. An increase in ODI with a decrease in MD and ND in the BM group may indicate an increase in network complexity (through higher dendritic branching) accompanied by dendritic pruning to enhance network efficiency. These neuroimaging outcomes conflict with the behavioral results, which showed poorer reaction time in the BM group. Given the exploratory outcomes and inconsistent findings between the behavioral and neuroimaging data, a larger study is needed to confirm the synaptogenic mechanisms of BM.

The effectiveness of Bacopa monnieri (Linn.) Wettst. as a nootropic, neuroprotective, or antidepressant supplement: analysis of the available clinical data

Bacopa monnieri (Linn.) Wettst. has been used in traditional medicine as a drug to enhance and improve memory. In this regard, this study aims to provide B. monnieri's efficacy as a neuroprotective drug and as a nootropic against various neurological diseases. Literatures were collected, following Prisma guidelines, from databases, including Scopus, PubMed, Google Scholar, and Science Direct and were scrutinized using a quality scoring system. Means, standard deviations and 'n' numbers were extracted from the metrics and analyzed. Jamovi computer software for Mac was used to carry out the meta-analysis. The selected studies suggested that the plant extracts were able to show some improvements in healthy subjects which were determined in Auditory Verbal Learning Task, digit span-reverse test, inspection time task and working memory, even though it was not significant, as no two studies found statistically significant changes in the same two tests. B. monnieri was able to express modest improvements in subjects with memory loss, wherein only a few of the neuropsychological tests showed statistical significance. B. monnieri in a cocktail with other plant extracts were able to significantly reduce the effects of Alzheimer's disease, and depression which cannot be solely credited as the effect of B. monnieri. Although in one study B. monnieri was able to potentiate the beneficial effects of citalopram; on the whole, currently, there are only limited studies to establish the memory-enhancing and neuroprotective effects of B. monnieri. More studies have to be done in the future by comparing the effect with standard drugs, in order to establish these effects clinically in the plant and corroborate the preclinical data.

Bacopa monnieri (L.) wettst. Extract protects against glutamate toxicity and increases the longevity of Caenorhabditis elegans

Background

Neurodegenerative diseases, such as Alzheimer’s disease, cause a great deal of suffering for both patients and carers. Bacopa monnieri (L.) wettst. Is known for its memory-enhancing properties, and is of great interest in treating neurodegenerative disease.

Aims

This study aimed to evaluate B.monnieri against glutamate toxicity, and identify whether B.monnieri reduces mitochondrial and ER stress, as well as to measure B.monnieri’s effect on the life span and aging of Caenorhabditis elegans. We hypothesized that B.monnieri would prevent cellular oxidative stress, prevent mitochondrial/ER stress, and increase the life span while reducing signs of aging in C.elegans.

Experimental procedures

Glutamate toxicity was measured using viable cell staining assays and the MTT assay. ROS and mitochondrial stress were assessed by H₂DCFDA and Rodamine123 staining, with fluorescence/confocal microscopy. C.elegans’ median and maximum life span were measured, in response to B.monnieri treatment, along with lipofuscin imaging to measure the health of the C.elegans population.

Results

B.monnieri hexane extract (but not ethanol extract) prevented the toxicity of 5 mM glutamate in HT-22 cells. We found that the mechanism involves the reduction of ROS production and the prevention of mitochondrial and ER stress. Furthermore, we showed that B.monnieri could increase the median and maximal lifespan of wild type C.elegans, maintain a younger appearing phenotype in the aged C.elegans.

Conclusions

In conclusion, B.monnieri prevents mitochondrial, and oxidative stress in the cultured cells. Furthermore, it can prolong the healthy lifespan of C.elegans, indicating that B.monnieri the potential for therapeutic and preventative use in neurodegenerative disease.

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First B.monnieri study to investigate the HT-22 cell glutamate toxicity model.

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B.monnieri protects HT-22 cells from oxidative stress caused by glutamate toxicity.

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B.monnieri prevents ER stress, changing the expression s of ER Stress proteins CHOP and ERP57.

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B.monnieri prevents mitochondrial stress, preventing mitochondrial leakage.

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B.monnieri increases the median and maximal life span, and reduces aging in wild type C.elegans.

Corticolimbic analysis of microRNAs and protein expressions in scopolamine-induced memory loss under stress

The aim of the present study was to assess thealterations of corticolimbic microRNAs and protein expressions in the effect of scopolamine with or without stress on passive-avoidance memory in male Wistar rats. The expressions of miR-1, miR-10 and miR-26 and also the levels of p-CREB, CREB, C-FOS and BDNF in the prefrontal cortex (PFC), the hippocampus and the amygdala were evaluated using RT-qPCR and Western blotting techniques. The data showed that the administration of a muscarinic receptor antagonist, scopolamine or the exposure to 30 min stress significantly induced memory loss. Interestingly, the injection of an ineffective dose of scopolamine (0.5 mg/kg) alongside with exposure to an ineffective time of stress (10 min) impaired memory formation, suggesting a potentiative effect of stress on scopolamine response. Our results showed that memory formation was associated with the down-regulated expression of miR-1, miR-10 and miR-26 in the PFC and the hippocampus, but not the amygdala. The relative expression increase of miR-1 and miR-10 in the PFC and the hippocampus was shown in memory loss induced by scopolamine administration or 30-min stress. The PFC level of miR-10 and also hippocampal level of miR-1 and miR-10 were significantly up-regulated, while amygdala miR-1 and miR-26 were down-regulated in scopolamine-induced memory loss under stress. Memory formation increased BDNF, C-FOS and p-CREB/CREB in the PFC, the hippocampus and the amygdala. In contrast, the PFC, hippocampal and amygdala protein expressions were significantly decreased in memory loss induced by scopolamine administration (2 mg/kg), stress exposure (for 30 min) or scopolamine (0.5 mg/kg) plus stress (10 min). One of the most significant findings to emerge from this study is that the stress exposure potentiated the amnesic effect of scopolamine may via affecting the expressions of miRs and proteins in the PFC, the hippocampus and the amygdala. It is possible to hypothesis that corticolimbic signaling pathways play a critical role in relationship between stress and Alzheimer's disease.

Bacopa monnieri extract improves novel object recognition, cell proliferation, neuroblast differentiation, brain-derived neurotrophic factor, and phosphorylation of cAMP response element-binding protein in the dentate gyrus

Bacopa monnieri is a medicinal plant with a long history of use in Ayurveda, especially in the treatment of poor memory and cognitive deficits. In the present study, we hypothesized that Bacopa monnieri extract (BME) can improve memory via increased cell proliferation and neuroblast differentiation in the dentate gyrus. BME was administered to 7-week-old mice once a day for 4 weeks and a novel object recognition memory test was performed. Thereafter, the mice were euthanized followed by immunohistochemistry analysis for Ki67, doublecortin (DCX), and phosphorylated cAMP response element-binding protein (CREB), and western blot analysis of brain-derived neurotrophic factor (BDNF). BME-treated mice showed moderate increases in the exploration of new objects when compared with that of familiar objects, leading to a significant higher discrimination index compared with vehicle-treated mice. Ki67 and DCX immunohistochemistry showed a facilitation of cell proliferation and neuroblast differentiation following the administration of BME in the dentate gyrus. In addition, administration of BME significantly elevated the BDNF protein expression in the hippocampal dentate gyrus, and increased CREB phosphorylation in the dentate gyrus. These data suggest that BME improves novel object recognition by increasing the cell proliferation and neuroblast differentiation in the dentate gyrus, and this may be closely related to elevated levels of BDNF and CREB phosphorylation in the dentate gyrus.

Bacopa monnieri extract enhances learning-dependent hippocampal long-term synaptic potentiation

Bacopa monnieri has been used in Ayurvedic medicine as a memory enhancer for a long time; however, its direct effect on synaptic plasticity has not been investigated. To the best of our knowledge, this study is the first to report the effect of B. monnieri on long-term synaptic potentiation in acute hippocampal slices. Adult male Wistar rats were orally administered either sterile water or the ethanolic extract of B. monnieri for 60 days. The extracellular recording was performed to measure the field excitatory postsynaptic potential in the acute hippocampal slices of these rats. Our results showed that B. monnieri extract significantly increased long-term potentiation magnitude compared with the control group, whereas there was no change in basal synaptic transmission. The data support the beneficial mnemonic effect of B. monnieri, and suggest that this effect might be because of the increase of learning-associated synaptic machinery, resulting in the long-term potentiation enhancement and strengthening of hippocampal synapses, which plays a critical role in learning and memory formation.

A bacosides containing Bacopa monnieri extract alleviates allodynia and hyperalgesia in the chronic constriction injury model of neuropathic pain in rats

BACKGROUND

The current therapy of neuropathic pain is inadequate and is limited by the extent of pain relief and the occurrence of dose dependant side effects. Insufficient control of pain with conventional medications prompts the use of complementary and alternative medicine therapies by patients with neuropathic pain. This study therefore investigated a standardized methanolic extract of Bacopa monnieri, a widely reputed nootropic plant, for prospective antinociceptive effect in the chronic constriction injury (CCI) model of neuropathic pain.

METHODS

Placement of four loose ligatures around the sciatic nerve produced partial denervation of the hindpaw in rats. Bacopa monnieri (40 and 80 mg/kg, p.o) and the positive control, gabapentin (75 mg/kg, i.p), were administered daily after CCI or sham surgery and the behavioral paradigms of static- and dynamic-allodynia (paw withdrawal threshold to von Frey filament stimulation [PWT] and paw withdrawal latency to light-brushing [PWL]), cold-allodynia (paw withdrawal duration [PWD] to acetone), heat- (PWL to heat-stimulus) and punctate-hyperalgesia (PWD to pin-prick) were assessed on days 3, 7, 14 and 21.

RESULTS

CCI consistently generated static- (days 3-21), dynamic- (days 14-21) and cold-allodynia (days 3-21) plus heat- and mechano-hyperalgesia (days 3-21). The tested doses of Bacopa monnieri significantly attenuated the CCI-induced allodynia and hyperalgesia, exemplified by increased PWT (days 7-21), PWL to light brushing (days 14-21) and heat (days 7-21) as well as decreased PWD to pin prick and cold stimuli (days 3-21). The extract also counterbalanced the CCI-induced aberrations in the nociceptive behaviors by increasing the pain threshold to that of pre-surgery baseline. Gabapentin also afforded analogous beneficial behavioral profile but of higher magnitude.

CONCLUSIONS

Our findings suggest that Bacopa monnieri can be used as adjuvant therapy for neuropathic pain conditions afflicted with allodynia and hyperalgesia.

Molecular Pathogenesis of Alzheimer's Disease: An Update

Dementia is a chronic or progressive syndrome, characterized by impaired cognitive capacity beyond what could be considered a consequence of normal aging. It affects the memory, thinking process, orientation, comprehension, calculation, learning ability, language, and judgment; although awareness is usually unaffected. Alzheimer's disease (AD) is the most common form of dementia; symptoms include memory loss, difficulty solving problems, disorientation in time and space, among others. The disease was first described in 1906 at a conference in Tubingen, Germany by Alois Alzheimer. One hundred and ten years since its first documentation, many aspects of the pathophysiology of AD have been discovered and understood, however gaps of knowledge continue to exist. This literature review summarizes the main underlying neurobiological mechanisms in AD, including the theory with emphasis on amyloid peptide, cholinergic hypothesis, glutamatergic neurotransmission, the role of tau protein, and the involvement of oxidative stress and calcium.

Cognitive training and Bacopa monnieri: Evidence for a combined intervention to alleviate age associated cognitive decline

As the elderly population grows the impact of age associated cognitive decline as well as neurodegenerative diseases such as Alzheimer's disease and dementia will increase. Ageing is associated with consistent impairments in cognitive processes (e.g., processing speed, memory, executive function and learning) important for work, well-being, life satisfaction and overall participation in society. Recently, there has been increased effort to conduct research examining methods to improve cognitive function in older citizens. Cognitive training has been shown to improve performance in some cognitive domains; including memory, processing speed, executive function and attention in older adults. These cognitive changes are thought to be related to improvements in brain connectivity and neural circuitry. Bacopa monnieri has also been shown to improve specific domains of cognition, sensitive to age associated cognitive decline (particularly processing speed and memory). These Bacopa monnieri dependent improvements may be due to the increase in specific neuro-molecular mechanisms implicated in the enhancement of neural connections in the brain (i.e. synaptogenesis). In particular, a number of animal studies have shown Bacopa monnieri consumption upregulates calcium dependent kinases in the synapse and post-synaptic cell, crucial for strengthening and growing connections between neurons. These effects have been shown to occur in areas important for cognitive processes, such as the hippocampus. As Bacopa monnieri has shown neuro-molecular mechanisms that encourage synaptogenesis, while cognitive training enhances brain connectivity, Bacopa monnieri supplementation could theoretically enhance and strengthen synaptic changes acquired through cognitive training. Therefore, the current paper hypothesises that the combination of these two interventions could improve cognitive outcomes, over and above the effects of administrating these interventions independently, as an effective treatment to ameliorate age associated cognitive decline.

Translation of Pre-Clinical Studies into Successful Clinical Trials for Alzheimer's Disease: What are the Roadblocks and How Can They Be Overcome?

Preclinical studies are essential for translation to disease treatments and effective use in clinical practice. An undue emphasis on single approaches to Alzheimer's disease (AD) appears to have retarded the pace of translation in the field, and there is much frustration in the public about the lack of an effective treatment. We critically reviewed past literature (1990-2014), analyzed numerous data, and discussed key issues at a consensus conference on Brain Ageing and Dementia to identify and overcome roadblocks in studies intended for translation. We highlight various factors that influence the translation of preclinical research and highlight specific preclinical strategies that have failed to demonstrate efficacy in clinical trials. The field has been hindered by the domination of the amyloid hypothesis in AD pathogenesis while the causative pathways in disease pathology are widely considered to be multifactorial. Understanding the causative events and mechanisms in the pathogenesis are equally important for translation. Greater efforts are necessary to fill in the gaps and overcome a variety of confounds in the generation, study design, testing, and evaluation of animal models and the application to future novel anti-dementia drug trials. A greater variety of potential disease mechanisms must be entertained to enhance progress.

The Molecular Links of Re-Emerging Therapy: A Review of Evidence of Brahmi (Bacopa monniera)

The convolution associated with memory is being resolved with advancement in neuroscience. According to the concurrent assumptions, synaptic plasticity forms one of the basis of memory formation, stabilization and strengthening. In Alzheimer's disease (AD), which is generally characterized by memory dysfunction, connections amongst the cells in the brain are attenuated or lost leading to degeneration of neural networks. Numerous attempts have been made to find new therapies for memory dysfunction with increasing attention and investments being laid on herbal drugs. Many herbal plants and extracts have already documented beneficial results when tested for antiamnesic effects. Brahmi (Bacopa monniera) is one such common herbal drug, which is employed for a long time in the Indian and Chinese medical system in order to treat several disorders. Previous research has shown that Brahmi exerts many pharmacological effects including memory boosting capacity in the treatment of Alzheimer's disease and Schizophrenia, exhibiting antiparkinsonian, antistroke, and anticonvulsant potentials. The present review discusses the chemical constituents of Brahmi along with in vitro and in vivo studies based on the pharmacological effects exerted by it. The efficacy of Brahmi in treating various disorders has evoked sufficient research in recent years and now it is a time to launch multiple clinical trials.

Efficacy of Natural Compounds in Neurodegenerative Disorders

Neurodegenerative disorders represent clusters of serious diseases that results in progressive deterioration of normal structure and physiology of central nervous system. Pathophysiology of Alzheimer's, Parkinson's or other neurodegenerative disorders involves multifaceted permutation of genetic and environmental factors. Combinations of lifestyle modification linked with environmental factor jointly or alone represent the largest share of cases of these disorders. Etiology of such neuronal degeneration involves manifestation of toxic reaction in the form of functional anomalies leading to dysfunction of the ubiquitin-proteasome system, activated inflammatory cascade, compromised neuronal survival pathway, mitochondrial dysfunction and finally neuronal apoptosis/necrosis and cell death. Furthermore, evidences from various studies exhibited role of oxidative stress and compromised anti-oxidant defense system as one of the prime factors associated with activation of various signal transduction pathways that would ultimately lead to the formation of amyloid beta or alpha synuclein in the brain. Keeping in view of complex etiology and pathophysiology along with a miniscule of available treatment options associated with these neurodegenerative disorders, the role of natural agents and herbal extracts as therapeutic alternatives alone or in combination with synthetic drugs could not be ruled out. In the same context the present chapter has been aimed to investigate the role of selected natural plants like Withania somnifera, Bacopa monnieri, Curcuma longa, Centella asiatica, Ocimum sanctum, Nardostachys jatamansi and Emblica officinalis in various neurodegenerative disorders and explore their targets to ameliorate neurotoxicity in various experimental models. The rationale for selection of these plants was based on their strong anti-inflammatory and anti-oxidant potential and large body of evidence that suggest their efficacy in preclinical as well as in clinical studies. Active constituents if these herbals might play an important role in preserving the integrity of various neurotransmitters and their receptor in the brain influencing its functions at the molecular level.

A Special Extract of Bacopa monnieri (CDRI-08) Restores Learning and Memory by Upregulating Expression of the NMDA Receptor Subunit GluN2B in the Brain of Scopolamine-Induced Amnesic Mice

In the present communication, we have investigated effects of the CDRI-08, a well characterized extract of Bacopa monnieri, on expression of the GluN2B subunit of NMDAR in various brain regions of the scopolamine-induced amnesic mice. Our behavioral data reveal that scopolamine-treated amnesic mice exhibit significant decline in the spatial memory compared to the normal control mice. Our RT-PCR and immunoblotting data revealed that the scopolamine treatment resulted in a significant downregulation of the NMDAR GluN2B subunit expression in prefrontal cortex and hippocampus. Our enzyme assay data revealed that scopolamine caused a significant increase in the acetylcholinesterase activity in both the brain regions. Further, oral administration of the CDRI-08 to scopolamine-treated amnesic mice restored the spatial memory which was found to be associated with significant upregulation of the GluN2B subunit expression and decline in the acetylcholinesterase activity in prefrontal cortex as well as hippocampus towards their levels in the normal control mice. Our study provides the evidence for the mechanism underlying role of the Bacopa monnieri extract (CDRI-08) in restoring spatial memory in amnesic mice, which may have therapeutic implications.

Molecular and Functional Characterization of Bacopa monniera: A Retrospective Review

Over the last 50 years, laboratories around the world analyzed the pharmacological effect of Bacopa monniera extract in different dimensions, especially as a nerve tonic and memory enhancer. Studies in animal model evidenced that Bacopa treatment can attenuate dementia and enhances memory. Further, they demonstrate that Bacopa primarily either acts via antioxidant mechanism (i.e., neuroprotection) or alters different neurotransmitters (serotonin (5-hydroxytryptamine, 5-HT), dopamine (DA), acetylcholine (ACh), γ-aminobutyric acid (GABA)) to execute the pharmacological effect. Among them, 5-HT has been shown to fine tune the neural plasticity, which is a substrate for memory formation. This review focuses on the studies which trace the effect of Bacopa treatment on serotonergic system and 5-HT mediated key molecular changes that are associated with memory formation.

D-cycloserine prevents relational memory deficits and suppression of long-term potentiation induced by scopolamine in the hippocampus

Previous research has demonstrated that systemic D-cycloserine (DCS), a partial agonist of the N-methyl-D-aspartate receptor (NMDAR), enhances memory processes in different learning paradigms and attenuates mnemonic deficits produced by diverse pharmacological manipulations. In the present study two experiments were conducted in rats to investigate whether DCS administered in the hippocampus may rescue relational memory deficits and improve deficient synaptic plasticity, both induced by an intracerebral injection of the muscarinic receptor antagonist scopolamine (SCOP). In experiment 1, we assessed whether DCS would prevent SCOP-induced amnesia in an olfactory learning paradigm requiring the integrity of the cholinergic system, the social transmission of food preference (STFP). The results showed that DCS (10 μg/site) injected into the ventral hippocampus (vHPC) before STFP acquisition compensated the 24-h retention deficit elicited by post-training intra-vHPC SCOP (40 μg/site), although it did not affect memory expression in non-SCOP treated rats. In experiment 2, we evaluated whether the perfusion of DCS in hippocampal slices may potentiate synaptic plasticity in CA1 synapses and thus recover SCOP-induced deficits in long-term potentiation (LTP). We found that DCS (50 µM and 100 µM) was able to rescue SCOP (100 µM)-induced LTP maintenance impairment, in agreement with the behavioral findings. Additionally, DCS alone (50 µM and 100 µM) enhanced field excitatory postsynaptic potentials prior to high frequency stimulation, although it did not significantly potentiate LTP. Our results suggest that positive modulation of the NMDAR, by activation of the glycine-binding site, may compensate relational memory impairments due to hippocampal muscarinic neurotransmission dysfunction possibly through enhancements in LTP maintenance.

Biologically inspired circuit model for simulation of glutamate gated ion channels of the postsynaptic membrane at synaptic cleft

Background

Enzyme modified field effect transistor (ENFET) may be used to represent the variable conductance of transmitter-gated ion channels in the postsynaptic region of the neuron.

Purpose

The objective of this work is to develop a simple analog circuit model that can simulate the function of neurotransmitter glutamate gated ion channels of postsynaptic membrane at the synaptic cleft.

Method

In this paper, Glutamate sensitive ENFET is incorporated into the Hodgkin-Huxley (H-H) circuit model of the postsynaptic membrane at the synaptic cleft.

Result

Simulation of the circuit model yields an output representing the membrane potential of the synaptic region. Simulation is performed in MATLAB environment for excitatory action of synapses.

Conclusion

This model can be used in neuro-bioengineering programs for simulation of binding activity and electrical activity of the postsynaptic region.

Molecular docking of bacosides with tryptophan hydroxylase: a model to understand the bacosides mechanism

Tryptophan hydroxylase (TPH) catalyses l-tryptophan into 5-hydroxy-l-tryptophan, which is the first and rate-limiting step of serotonin (5-HT) biosynthesis. Earlier, we found that TPH2 up-regulated in the hippocampus of postnatal rats after the oral treatment of Bacopa monniera leaf extract containing the active compound bacosides. However, the knowledge about the interactions between bacosides with TPH is limited. In this study, we take advantage of in silico approach to understand the interaction of bacoside-TPH complex using three different docking algorithms such as HexDock, PatchDock and AutoDock. All these three algorithms showed that bacoside A and A3 well fit into the cavity consists of active sites. Further, our analysis revealed that major active compounds bacoside A3 and A interact with different residues of TPH through hydrogen bond. Interestingly, Tyr235, Thr265 and Glu317 are the key residues among them, but none of them are either at tryptophan or BH4 binding region. However, its note worthy to mention that Tyr 235 is a catalytic sensitive residue, Thr265 is present in the flexible loop region and Glu317 is known to interacts with Fe. Interactions with these residues may critically regulate TPH function and thus serotonin synthesis. Our study suggested that the interaction of bacosides (A3/A) with TPH might up-regulate its activity to elevate the biosynthesis of 5-HT, thereby enhances learning and memory formation.

Neurochemical changes observed by in vivo proton magnetic resonance spectroscopy in the mouse brain postadministration of scopolamine

RATIONALE AND OBJECTIVES

This study is aimed at investigating neurochemical changes in scopolamine (SCP)-induced memory impairment using spatially localized in vivo magnetic resonance spectroscopy (MRS) of the hippocampus.

MATERIALS AND METHODS

Four groups of mice (eight mice per group) were scanned after the injection of different SCP doses: 0, 1, 3, and 5 mg/kg (intraperitoneally). All the animals received (1)H MRS of their hippocampus at two time intervals: 30 minutes and 72 hours after SCP injection.

RESULTS

This work demonstrated that the doses of 3 mg/kg SCP or higher reduce the concentration of total choline-containing compounds, and these levels returned to baseline after 72 hours. These results are consistent with observations made by others using more invasive brain dialysis approaches. The levels of glutamate and glutamic compounds (glutamate + glutamine) were slightly changed at 3 and 5 mg/kg SCP dose, but the differences were not statistically significant (P > .05). These findings suggest that SCP produces transient, in vivo measurable alterations in the cholinergic system in the hippocampus.

CONCLUSIONS

On this basis, we conclude that in vivo MRS is a feasible noninvasive method to probe aspects of the alterations induced by SCP in the cholinergic neurotransmission pathways in both animal models and human studies of memory impairment.

Study of Brāhmī Ghṛta and piracetam in amnesia

Objective:

To compare the effect of Brāhmī Ghṛta with piracetam (a reference standard chemical) in amnesia.

Materials and Methods:

Brāhmī Ghṛta contained Brāhmī (Bacopa monneri), Vacā (Acorus calamus), Kuṣṭha (Sassurea lappa), Śaṅkhapuṣpī (Convolvulos pluricalis), and Purāṇa Ghṛta, prepared as per snehapāka process. Antiamnesic activity of Brāhmī Ghṛta (400 and 800 mg/kg, p.o.) was evaluated in scopolamine (1 mg/kg, s.c.) induced amnesia in Charles Foster rats using elevated plus maze, passive avoidance, and active avoidance tests. Piracetam (500 mg/kg, p.o.) was used as standard drug. This effect was compared with standard chemical used in experimental study.

Results:

Brāhmī Ghṛta - (in both doses) and piracetam-treated rats significantly reversed the effect of scopolamine in modified elevated plus maze, passive avoidance, and active avoidance tests. But there were no significant differences observed in antiamnesic activity of Brāhmī Ghṛta and standard drug.

Conclusion:

Brāhmī Ghṛta and piracetam produced significant beneficial effect on scopolamine-induced amnesic effect, but no significant difference was observed in between them.

Neuropharmacological review of the nootropic herb Bacopa monnieri

This review synthesizes behavioral research with neuromolecular mechanisms putatively involved with the low-toxicity cognitive enhancing action of Bacopa monnieri (BM), a medicinal Ayurvedic herb. BM is traditionally used for various ailments, but is best known as a neural tonic and memory enhancer. Numerous animal and in vitro studies have been conducted, with many evidencing potential medicinal properties. Several randomized, double-blind, placebo-controlled trials have substantiated BM's nootropic utility in humans. There is also evidence for potential attenuation of dementia, Parkinson's disease, and epilepsy. Current evidence suggests BM acts via the following mechanisms-anti-oxidant neuroprotection (via redox and enzyme induction), acetylcholinesterase inhibition and/or choline acetyltransferase activation, β-amyloid reduction, increased cerebral blood flow, and neurotransmitter modulation (acetylcholine [ACh], 5-hydroxytryptamine [5-HT], dopamine [DA]). BM appears to exhibit low toxicity in model organisms and humans; however, long-term studies of toxicity in humans have yet to be conducted. This review will integrate molecular neuroscience with behavioral research.

Evaluation of standardized Bacopa monniera extract in sodium fluoride-induced behavioural, biochemical, and histopathological alterations in mice

Effect of standardized Bacopa monniera (BM; family: Scrophulariaceae) extract (100 and 300 mg/kg) against sodium fluoride (NaF; 100 and 200 ppm)-induced behavioural, biochemical, and neuropathological alterations in mice was evaluated. Akinesia, rotarod (motor coordination), forced swim test (depression), open field test (anxiety), transfer latency (memory), cholinesterase (ChE), and oxidative stress (superoxide dismutase, catalase, glutathione peroxidase, and lipid peroxidation) were determined in mice treated with NaF for 30 days alone and in combination with BM. NaF induced motor incoordination, depression, and memory impairment, and these were prevented by coadministration of BM in mice. However, NaF did not alter the weight gain, feed/water consumption, and anxiety profile. Suppression of ChE levels and increased oxidative stress were observed in mice treated with NaF. Coadministration of BM significantly improved the memory, ChE levels, and antioxidant enzymes but failed to alter the fluoride levels in NaF-treated mice. Histopathological studies revealed that BM protected the neuropathological alterations induced by NaF.

Attenuation of 1-(m-chlorophenyl)-biguanide induced hippocampus-dependent memory impairment by a standardised extract of Bacopa monniera (BESEB CDRI-08)

Bacopa monniera is a well-known medhya-rasayana (memory enhancing and rejuvenating) plant in Indian traditional medical system of Ayurveda. The effect of a standardized extract of Bacopa monniera (BESEB CDRI-08) on serotonergic receptors and its influence on other neurotransmitters during hippocampal-dependent learning was evaluated in the present study. Wistar rat pups received a single dose of BESEB CDRI-08 during postnatal days 15-29 showed higher latency during hippocampal-dependent learning accompanied with enhanced 5HT(3A) receptor expression, serotonin and acetylcholine levels in hippocampus. Furthermore, 5HT(3A) receptor agonist 1-(m-chlorophenyl)-biguanide (mCPBG) impaired learning in the passive avoidance task followed by reduction of 5HT(3A) receptor expression, 5HT and ACh levels. Administration of BESEB CDRI-08 along with mCPBG attenuated mCPBG induced behavioral, molecular and neurochemical alterations. Our results suggest that BESEB CDRI-08 possibly acts on serotonergic system, which in turn influences the cholinergic system through 5-HT(3) receptor to improve the hippocampal-dependent task.

Bacopa monniera leaf extract up-regulates tryptophan hydroxylase (TPH2) and serotonin transporter (SERT) expression: implications in memory formation

AIM OF THE STUDY

To examine the effect of Bacopa monniera leaf ethanolic extract (BMEE) on the serotonergic system of postnatal rats with reference to learning and memory.

MATERIALS AND METHODS

From postnatal day (PND)-15-29, rats were treated with BMEE (40 mg/kg BW+0.5% gum acacia) by oral gavage. Behavioural tests (Y-maze, hole-board and passive avoidance) were used to evaluate their learning (PND-32-37) and retention of memory (PND-47-53). Effect of BMEE on neurotransmitter system was analyzed by ELISA and semi-quantitative polymerase chain reaction (PCR).

RESULTS

Oral administration of BMEE improved learning and retention of memory significantly in all behavioural tasks. Following BMEE treatment, the level of serotonin (5-HT) increased while dopamine (DA) decreased significantly. We also found variation in the level of acetylcholine (ACh). However, no significant changes were observed in the level of ACh and glutamate (Glu). The level of 5-HT was significantly elevated up to PND-37 and was then restored to normal level on PND-53. Interestingly, concomitant up-regulation was recorded in the mRNA expression of serotonin synthesizing enzyme tryptophan hydroxylase-2 (TPH2) and serotonin transporter (SERT) on PND-29 and PND-37, which was restored on PND-53.

CONCLUSIONS

The results suggest that BMEE treatment significantly enhances the learning and retention of memory in postnatal rats possibly through regulating the expression of TPH2, 5-HT metabolism and transport.

Loss of learning in mice when exposed to rat odor: a water maze study

The study was designed to test the hypothesis if predator stress can affect learning in mice when exposed to rat odor. We investigated the spatial memory performance of Swiss albino mice in a 7 d Morris water maze (MWM) paradigm by exposing them to the odor of predator (Wistar rats). The results revealed that rat odor produced amnesia in the mice while mice odor did not affect learning in rats, analyzed by the escape latency time (ELT) in acquition trials and search error in retrieval trials. Moreover, the memory loss in mice was comparable to the degree of amnesia produced by scopolamine, a control amnesic agent.

Effects of mitragynine from Mitragyna speciosa Korth leaves on working memory

AIM OF THE STUDY

Mitragyna speciosa Korth from Rubiaceae family is a tropical plant indigenous to Southeast Asia particularly in Thailand, Peninsular of Malaysia and Indonesia. The leaves have been used by natives for their opium-like effect and cocaine-like stimulant ability to combat fatigue and enhance tolerance to hard work. However there is no scientific information about the effect of mitragynine on the cognitive performances. This study is designed to examine the working memory effects of mitragynine which is extracted from Mitragyna speciosa mature leaves.

MATERIALS AND METHODS

The cognitive effect was studied using object location task and the motor activity in open-field test. Mitragynine 5, 10 and 15 mg/kg and were administered by intraperitoneal (IP) for 28 consecutive days and evaluated on day 28 after the last dose treatment. Scopolamine was used as the control positive drug.

RESULTS

In this study there is prominent effects on horizontal locomotor activity was observed. Mitragynine significantly reduced locomotor activity in open-field test compared with vehicle. In object location task mitragynine (5, 10 and 15 mg/kg) did not showed any significances discrimination between the object that had changed position than the object that had remain in a constant position.

CONCLUSION

Our results suggest that chronic administration of mitragynine can altered the cognitive behavioral function in mice.

Behavioral deficit and decreased GABA receptor functional regulation in the cerebellum of epileptic rats: effect of Bacopa monnieri and bacoside A

In the present study, the effects of Bacopa monnieri and its active component, bacoside A, on motor deficit and alterations of GABA receptor functional regulation in the cerebellum of epileptic rats were investigated. Scatchard analysis of [(3)H]GABA and [(3)H]bicuculline in the cerebellum of epileptic rats revealed a significant decrease in B(max) compared with control. Real-time polymerase chain reaction amplification of GABA(A) receptor subunits-GABA(Aalpha1), GABA(Aalpha5,) and GABA(Adelta)-was downregulated (P<0.001) in the cerebellum of epileptic rats compared with control rats. Epileptic rats exhibit deficits in radial arm and Y-maze performance. Treatment with B. monnieri and bacoside A reversed these changes to near-control levels. Our results suggest that changes in GABAergic activity, motor learning, and memory deficit are induced by the occurrence of repetitive seizures. Treatment with B. monnieri and bacoside A prevents the occurrence of seizures thereby reducing the impairment of GABAergic activity, motor learning, and memory deficit.