Development and characterization of an automated behavioral assessment platform for the Göttingen minipig

The Göttingen minipig is fast becoming the standard for assessing dermal chemical hazards because, like most swine, its skin is predictive of human skin response and because this strain's smaller size makes laboratory manipulations and husbandry easier. Unfortunately, standard behavioral tests and apparatus have not been developed for behavioral assessments of this swine strain. Indeed, computer-controlled automated behavioral testing procedures are much needed. The present research advanced this goal by producing a home-cage behavioral testing system that could accommodate minipigs of various sizes (ages). An aluminum frame housed three levers for recording operant responses, and LEDs above and below each lever served as discriminative stimuli. A commercially available food pellet dispenser was attached to a specialized pellet receptacle capable of measuring pellet retrieval. Two behavioral tests were selected and adapted from our commonly used non-human primate behavioral assessments: delayed match-to-sample (a memory test) and temporal response differentiation (a time-estimation test). Minipigs were capable of learning both tests and attaining stable performance. Next, scopolamine was used to validate the sensitivity of the behavioral tests for gauging behavioral perturbations in this swine strain. Scopolamine dose-effect functions were comparable to those observed in other species, including non-human primates, wherein 37.5 µg/kg of scopolamine (administered intramuscularly) reduced responding approximately 50%. Thus, we were successful in developing the apparatus and automated operant behavioral tests necessary to characterize drug safety in this swine strain. This capability will be valuable for characterizing chemical agent toxicity as well as the safety and efficacy of medical countermeasures.

Quercetin-loaded nanoemulsions prevent Scopolamine-induced neurotoxicity in male rats

Quercetin (QCT) is well-known as a neuroprotective agent due to its antioxidant capacities and reinstating mitochondrial functions. Scopolamine is commonly used as a model to induce Alzheimer's disease (AD-like) symptoms. The current study develops QCT-loaded nanoemulsion (QCT-NE) accompanied by evaluating its neuro-therapeutic effectiveness against SCO-induced neurotoxicity in male rats. The QCT-NE was prepared by the spontaneous emulsification technique and characterized by using particle size, zeta potential, drug loading, in vitro drug release behavior, and stability studies. In vivo studies were done on adult Wistar rats by applying the Morris water maze (MWM) test to study spatial memory and learning. The levels of lipid peroxidation and reduced glutathione were quantitatively determined to reveal the potential mechanism of SCO-induced oxidative stress. Finally, histological studies were performed using staining techniques. The QCT-NE particle size, zeta potential, polydispersity index (PDI), and DL were obtained at 172.4 ± 16.8 nm, -29 ± 0.26 mV, 0.3 ± 0.07, and 81.42 ± 9.14 %, respectively. The QCT and more effectively QCT-NE reduced the elevation of neurobehavioral abnormalities in the MWM test in SCO-exposed rats. The results of oxidative status showed that SCO significantly could increase the LPO and decrease the GSH levels in the rat's brain. However, QCT-NE treatment was more effective than free QCT to inhibit oxidative damage and was well correlated with histopathological findings. Taken together, QCT-NE, compared to QCT, was superior in ameliorating SCO-induced AD-like symptoms due to its better neuroprotective activity and can be considered a novel supplementary therapeutic agent in AD management.

Neuroprotective and anti-amnesic effects of Laurus Nobilis essential oil against scopolamine-induced memory deficits in mice brain

ETHNOPHARMACOLOGICAL RELEVANCE

Laurus nobilis L. (Lauraceae family) has been widely used in traditional Tunisian medicine for the treatment of different health problems such as rheumatism and some neurological disorders.

AIM

In this study, the essential oil obtained from Laurus nobilis L. species from Tunisia (LEO) was studied for its chemical composition and anti-amnesic activities on memory impairment caused by scopolamine injection in mice. The major compounds of LEO oil, 1,8-cineole and, α-terpinyl acetate were docked with AChE (Acetylcholinesterase), using Autodock Vina and Discovery Studio visualizer software.

MATERIALS AND METHODS

The Morris water maze (MWM) tests and the Y maze were used to assess the anti-amnesic effects of LEO in mice with scopolamine-induced memory impairments. In brain tissues, the levels of biomarkers, enzyme activity, and protein expression related to the cholinergic system were measured.

RESULTS

Chronic administration of scopolamine led to a significant decline in cognitive performance in both the Morris Water Maze (MWM) and Y maze tests, accompanied by pronounced oxidative damage and a significant increase in acetylcholinesterase activity compared to the other groups. However, compared to the scopolamine group, treatment with LEO (100 mg/kg) significantly enhanced cognitive function and ameliorated the oxidative damage (p < 0.05 versus scopolamine) CONCLUSION: This study demonstrates the beneficial effect of LEO on scopolamine-induced dementia in mice, potentially achieved through the modulation of cholinergic activity and antioxidant properties. The docking analysis of the major compounds, 1,8-cineole and α-terpinyl acetate, further substantiates their potential as memory enhancers.

Effects and mechanism of extracts rich in phenylpropanoids-polyacetylenes and polysaccharides from Codonopsis Radix on improving scopolamine-induced memory impairment of mice

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD) is a progressive developmental neurodegenerative disease that primarily develops in old age. Memory impairment is an important manifestation of AD. It has been demonstrated that inflammation and oxidative stress are important mediators in the development and progression of AD. Codonopsis Radix (CR) has a long history of consumption, exhibiting lots of beneficial health effects, including anti-ageing, antioxidant, and anti-inflammatory properties. However, studies on the effects of CR on scopolamine-induced amnesia have rarely been reported.

AIM OF THE STUDY

The aim of this study was to investigate the ameliorative effect of macromolecular portion (polysaccharides, POL) and small molecule portion (fine extract rich in phenylpropanoids-polyacetylenes, EPP) from CR on improving scopolamine-induced memory impairment and to elucidate the potential mechanism of action.

MATERIALS AND METHODS

C57BL/6 mice were pretreated with EPP (0.2, 0.4, and 0.6 g/kg), POL (0.3, 0.6, and 0.9 g/kg), and donepezil (5 mg/kg) by gavage for 7 days, followed by intraperitoneal injection of scopolamine (1 mg/kg) to induce memory impairment. The 16S rRNA gene sequencing, histopathological, western blotting, and biochemical analysis (various biochemical markers and protein expressions related to cholinergic system, oxidative stress, and neuroinflammation) were performed to further elucidate the mechanism of action. Moreover, the acetylcholinesterase (AChE) inhibitory activities of POL, EPP, and its main compounds tangshenoside I, lobetyol, lobetyolin, and lobetyolinin were evaluated.

RESULTS

Experiments have confirmed that both POL and EPP from CR could improve scopolamine-induced spatial learning memory deficits. Both of them could regulate cholinergic function by inhibiting AChE and activating choline acetyltransferase (ChAT) activities. They also could enhance antioxidant defense via increasing the activities of superoxide dismutase and glutathione peroxidase, and anti-inflammatory function through suppressing inflammatory factors (nitric oxide, TNF-α, and IL-6) and regulating gut flora. Besides, in vitro experiments demonstrated that four monomeric compounds and EPP, except POL, exhibited inhibition of AChE activity.

CONCLUSION

EPP and POL from CR exert a beneficial effect on learning and memory processes in mice with scopolamine-induced memory impairment. CR may be a promising medicine for preventing and improving learning memory.

Ethanol extract of Evodia lepta Merr. ameliorates cognitive impairment through inhibiting NLRP3 inflammasome in scopolamine-treated mice

Evodia lepta Merr. (Evodia lepta) is a well-known traditional Chinese medicine, which has been widely used in herbal tea. We previously reported that the coumarin compounds from the root of Evodia lepta exhibited neuroprotective effects. However, whether Evodia lepta could inhibit NLRP3 inflammasome in dementia was still unknown. In this study, the components of the Evodia lepta extract were identified by HPLC-Q-TOF HRMS. We employed a scopolamine-treated mouse model. Evodia lepta extract (10 or 20 mg/kg) and donepezil were treated by gavage once a day for 14 consecutive days. Following the behavioral tests, oxidative stress levels were measured. Then, Western blot and immunofluorescence analysis were used to evaluate the expressions of NLRP3 inflammasome. 14 major components of the Evodia lepta extract were identified by HPLC-Q-TOF HRMS. The results of Morris water maze, object recognition task and open field test indicated that Evodia lepta extract could ameliorate cognitive impairment in scopolamine-treated mice. Evodia lepta extract improved cholinergic system. Moreover, Evodia lepta extract improved the expressions of PSD95 and BDNF. Evodia lepta extract suppressed neuronal oxidative stress and apoptosis. In addition, Evodia lepta extract inhibited NLRP3 inflammasome in the hippocampus of scopolamine-treated mice. Evodia lepta extract could protect against cognitive impairment by inhibiting NLRP3 inflammasome in scopolamine-treated mice.

Neuroprotective effects of Petiveria alliacea on scopolamine-induced learning and memory impairment mouse model

ETHNOPHARMACOLOGY RELEVANCE

Petiveria alliacea L., commonly known as macura and gully root, is an important medicinal plant used in the Caribbean and Central America to treat ailments associated to the central nervous system, including poor memory.

AIM OF THE STUDY

To assess the effects of the P. alliacea leaves methanol fraction (PMF) on a scopolamine-induced learning and memory impairment mouse model related to acetylcholinesterase activity and oxidative stress.

MATERIAL AND METHODS

After PMF administration at doses of 500 or 900 mg/kg, cognitive ability was evaluated using the Morris water maze (MWM), Y-maze (YM) and novel object recognition (NOR) tests. The mouse brain tissue was further assessed for acetylcholinesterase activity and antioxidant activity. Levels of oxidative stress were also evaluated by measuring malondialdehyde (MDA) and glutathione activity. Acute toxicity was also evaluated.

RESULTS

PMF led to memory improvement in the behavioral tests in mice with scopolamine-induced cognitive impairment. Moreover, PMF inhibited acetylcholinesterase activity and showed antioxidant potential that in turn attenuated cholinergic degradation. Additionally, PMF increased glutathione levels and glutathione reductase activity and reduced MDA levels in the brain. Moreover, no acute toxicity was detected with the use of PMF.

CONCLUSION

In a mouse model of scopolamine-induced cognitive deficit, PMF exhibited protective effects, decreasing oxidative damage and regulating cholinergic function in the brain bearing significant memory enhancing potency. These data suggest that PMF is a promising candidate for developing therapies for neurodegenerative disorders.

(m) RVD-hemopressin (α) Ameliorated Oxidative Stress, Apoptosis and Damage to the BDNF/TrkB/Akt Pathway Induced by Scopolamine in HT22 Cells

Dysfunction in the cholinergic system and oxidative stress are closely related and play roles in Alzheimer's disease (AD). Scopolamine (Scop), which is commonly used to induce cholinergic system damage in cells and animals, also evokes oxidative stress. Our previous study indicated that the peptide (m) RVD-hemopressin (RVD) reversed the memory-impairing effect of Scop in mice by activating cannabinoid receptor 1 (CBR1), but the mechanism was unclear. In this study, we found that RVD inhibited the oxidative stress, apoptosis, decreased cell viability and downregulation of synapse-associated proteins induced by Scop in HT22 cells. The effect was associated with the BDNF/TrkB/Akt pathway, and the effects of RVD outlined above could be blocked by an antagonist of CBR1. These results suggest that RVD may be a potential drug candidate for disorders associated with damage to the cholinergic system and oxidative stress, such as AD.

Scopolamine causes delirium-like brain network dysfunction and reversible cognitive impairment without neuronal loss

Delirium is a severe acute neuropsychiatric syndrome that commonly occurs in the elderly and is considered an independent risk factor for later dementia. However, given its inherent complexity, few animal models of delirium have been established and the mechanism underlying the onset of delirium remains elusive. Here, we conducted a comparison of three mouse models of delirium induced by clinically relevant risk factors, including anesthesia with surgery (AS), systemic inflammation, and neurotransmission modulation. We found that both bacterial lipopolysaccharide (LPS) and cholinergic receptor antagonist scopolamine (Scop) induction reduced neuronal activities in the delirium-related brain network, with the latter presenting a similar pattern of reduction as found in delirium patients. Consistently, Scop injection resulted in reversible cognitive impairment with hyperactive behavior. No loss of cholinergic neurons was found with treatment, but hippocampal synaptic functions were affected. These findings provide further clues regarding the mechanism underlying delirium onset and demonstrate the successful application of the Scop injection model in mimicking delirium-like phenotypes in mice.

Zinc Ortho Methyl Carbonodithioate Improved Pre and Post-Synapse Memory Impairment via SIRT1/p-JNK Pathway against Scopolamine in Adult Mice

Alzheimer's disease (AD) is globally recognized as a prominent cause of dementia for which efficient treatment is still lacking. New candidate compounds that are biologically potent are regularly tested. We, therefore, hypothesized to study the neuroprotective potential of Zinc Ortho Methyl Carbonodithioate (thereafter called ZOMEC) against Scopolamine (SCOP) induced Alzheimer's disease (AD) model using adult albino mice. We post-administered ZOMEC (30 mg/Kg) into two group of mice for three weeks on daily basis that received either 0.9% saline or SCOP (1 mg/Kg) for initial two weeks. The other two groups of mice received 0.9% saline and SCOP (1 mg/Kg) respectively. After memory related behavioral analysis the brain homogenates were evaluated for the antioxidant potential of ZOMEC and multiple protein markers were examined through western blotting. Our results provide enough evidences that ZOMEC decrease oxidative stress by increasing catalase (CAT) and glutathione S transferase (GST) and decreasing the lipid peroxidation (LPO). The SIRT1 and pre and post synaptic marker proteins, synaptophysin (SYP) as well as post synaptic density protein (PSD-95) expression were also enhanced upon ZOMEC treatment. Furthermore, memory impairment was rescued and ZOMEC appreciably abrogated the Aβ accumulation, BACE1 expression C and the p-JNK pathway. The inflammatory protein markers, NF-kβ and IL-1β in ZOMEC treated mice were also comparable with control group. The predicted interaction of ZOMEC with SIRT1 was further confirmed by molecular docking. These findings thus provide initial reports on efficacy of ZOMEC in SCOP induced AD model.

Capparis spinosa Promoted BDNF and Antioxidant Enzyme Levels to Protect Against Learning and Memory Deficits Induced by Scopolamine

BACKGROUND

Alzheimer's disease (AD) is a major neurodegenerative disorder with multiple manifestations, including oxidative stress, brain-derived neurotrophic factor (BDNF) depletion, and cholinergic dysfunction. Capparis spinosa (C. spinosa) is identified as a potential source of nutrition for alleviating various ailments. The current study assessed the ameliorating properties of C. spinosa hydroethanolic extract on memory dysfunction and the possible roles of oxidative stress and BDNF in the scopolamine (Scop)-treated rats.

METHODS

Forty male Wistar rats were divided into the following four groups: Control, Scop (2 mg/kg, intraperitoneal injection (i.p.)), Scop + C. spinosa 150, and Scop + C. spinosa 300 groups. The rats were given C. spinosa extract (150 or 300 mg/kg, oral) for 3 weeks. During the third week, Passive Avoidance (PA) and Morris Water Maze (MWM) tests were done to assess memory and learning performance. Finally, oxidative stress markers and BDNF in the brain tissue were evaluated.

RESULTS

Scop injection was associated with a significant increase in the time latency and travelled distance to reach the platform during the learning phase of MWM In the probe test, the Scoptreated rats showed a lower time and distance in the target area. Furthermore, Scop injection significantly decreased the latency to enter the dark while increasing the dark time and the frequency of entries to the dark zone of the PA task. C. spinosa extract effectively reversed the behavioural changes induced by Scop. Treatment with the extract also significantly increased the levels of superoxide dismutase, catalase, thiols, and BDNF, while decreasing malondialdehyde production in the brains of the Scop-injured rats.

CONCLUSION

C. spinosa hydroethanolic extract successfully ameliorated Scop-induced memory impairment by modifying BDNF and oxidative stress markers in the brain of amnesic rats.

Evaluation of the Effect of Cariprazine on Memory and Cognition in Experimental Rodent Models

The main symptoms of schizophrenia are categorized as positive, negative, and cognitive. Cognitive impairments do not generally respond to antipsychotics. Cariprazine is a novel antipsychotic conceived with the idea that high affinity for D3 receptors may elicit a favorable response in the management of cognitive deficits. We evaluated the pro-cognitive properties of 14-day long pre-treatment with cariprazine (0.25, 0.5, and 1 mg/kg b.w. intraperitoneally) in experimental rodent models with scopolamine-induced memory impairment employing novel object recognition test (NORT), T-maze, Y-maze, and passive avoidance tasks (step-through and step-down). Statistical analysis was performed with One Way ANOVA. In NORT cariprazine increased the recognition index. In T-maze and Y-maze cariprazine increased the working memory index as well as the percentage of spontaneous alternation. Cariprazine improved learning and memory in both short-term and long-term memory retention tests in step-down and step-through tasks. Cariprazine improves learning, recognition, and spatial memory in rats with scopolamine-induced memory impairment. Cariprazine's beneficial effect on cognition is likely due to its affinity for D3 receptors, as well as agonism at 5-HT1A receptors. Most probably, the cognitive-enhancing properties of cariprazine are the result of integrated modulation in the amygdala, hippocampus, and prefrontal cortex.

Sea Cucumber-Derived Peptide Attenuates Scopolamine-Induced Cognitive Impairment by Preventing Hippocampal Cholinergic Dysfunction and Neuronal Cell Death

The incidence of neurodegenerative diseases related to cognitive decline and memory loss is on the rise as the global elderly population increases. In this study, we evaluated the effect of the sea cucumber-derived peptide Phe-Tyr-Asp-Trp-Pro-Lys (FYDWPK) on scopolamine-induced neurotoxicity in an animal model. The Morris water maze, passive avoidance apparatus, and shuttle box test were used to assess learning and memory abilities. In behavioral tests, FYDWPK effectively alleviated learning and memory impairment. FYDWPK also alleviated cholinergic dysfunction in mice with dementia. Furthermore, FYDWPK significantly improved oxidative imbalance by increasing superoxide dismutase activity and decreasing malondialdehyde levels (P < 0.05). The pathological results showed that FYDWPK alleviated neuronal loss, blurred caryotheca, and pyknotic nuclei in the hippocampus, and a high dose of FYDWPK had the best effect. In conclusion, FYDWPK alleviated cognitive and memory impairments by regulating oxidative imbalance, reducing cholinergic dysfunction, and relieving pathological alterations.

Studying the interaction of scopolamine with calf-thymus DNA: An in-vitro and in-silico approach and genotoxicity

Scopolamine is used to treat various CNS disorder like urinary incontinence, motion sickness, spasmic movements. Despite its pharmaceutical properties, its interaction with DNA is not yet reported. In this article, the interaction between scopolamine and ct-DNA is reported using a combination of biophysical techniques. UV-visible and steady-state fluorescence spectroscopy were used to study interaction and complex formation. Competitive displacement assays and potassium iodide quenching confirmed the mode of binding between scopolamine and DNA. Structural changes induced in the ct-DNA in the presence of scopolamine were evaluated by CD spectroscopy. The plasmid nicking and NBT assay confirmed the genotoxic effect of scopolamine. In-silico study by molecular docking and molecular dynamics simulation revealed the mode of interaction, major stabilizing forces as well as the nucleotide sequences to which the scopolamine binds.

The modulatory role of prime identified compounds in Geophila repens in mitigating scopolamine-induced neurotoxicity in experimental rats of Alzheimer's disease via attenuation of cholinesterase, β-secretase, MAPt levels and inhibition of oxidative stress imparts inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Geophila repens (L.) I.M. Johnst (Rubiaceae) is a small perennial creeper native to India, China, and other countries in Southeast Asia. The hot decoction of leaves is used orally for memory enhancing by the local folk of Andhra Pradesh, India. The ethnomedicinal claim of G. repens as memory enhancer was initially studied by the authors. Results demonstrated the important antioxidant and anticholinesterase activities of isolated molecule Pentylcurcumene and bioactive hydroalcohol extract of leaves of G. repens (GRHA).

AIM OF THE STUDY

Based on the previous findings, additional research is needed to examine the efficacy of GRHA for memory enhancing properties. We therefore investigated the modulatory role of prime identified compounds in GRHA in mitigating scopolamine-induced neurotoxicity in experimental rats of Alzheimer's disease (AD) via attenuation of cholinesterase, β-secretase, MAPt levels and inhibition of oxidative stress imparts inflammation.

METHODS

Scopolamine (3 mg/kg) induced experimental rats of AD were treated with GRHA (300, 400 mg/kg) for 14 days. During the experimental period, elevated T-maze and locomotion-activity were performed to assess learning and memory efficacy of GRHA. At the end of the experiment, biochemical, neurochemical, neuroinflammation and histopathological observation of brain cortex were examined. GC-MS/MS analysis reported 31 compounds, among them 8 bioactive compounds possess antioxidant, neuroinflammation, neuroprotective activities, and were considered for docking analysis towards cholinesterase, β-secretase activities in AD.

RESULTS

GRHA 400 significantly improved learning and memory impairment with the improvement of oxidative stress (MDA, SOD, GSH, CAT), DNA damage (8-OHdG), neurochemical (AChE, BuChE, BACE1, BACE2, MAPt), neuroinflammation (IL-6, TNF-α) markers in neurotoxic rats. Docking studies of 8 compounds demonstrated negative binding energies for cholinesterase and β-secretase indicating high affinity for target enzymes in AD. Test results were corroborated by the improvement of cellular tissue architecture of brain cortex in AD rats.

CONCLUSION

Synergistic action of genistin, quercetin-3-D-galactoside, 9,12,15-octadecatrienoic-acid methyl-ester, phytol, retinal, stigmasterol, n-hexadecanoic acid, β-sitosterol in GRHA restores memory-deficits via attenuation of cholinesterase, β-secretase, MAPt level and inhibition of oxidative-stress imparts inflammation in AD.

Hippocampal Astrogliotic Reduction in Scopolamine Hydrobromide-Induced Alzheimer's Type Cognitive Dysfunction Wistar Rats Following Administration of Aqueous Extract of Telfairia Occidentalis (pumpkin) seeds

Astrocytes are small star-shaped glial cells that maintain normal human brain physiology including secretion of several active compounds and the formation of blood brain barrier. Reactive astrocytes support regenerating axons and also, actuate some genes responsible for the induction of synapse formation. In this study, the effect of aqueous extract of Telfairia occidentalis seeds on hippocampal astrogliosis was probed using scopolamine-induced Alzheimer's type cognitive dysfunction Wistar rats. Thirty Wistar rats weighed between 180-200g were randomly grouped into five designated A, B, C, D and E.  Each group contained six rats. Alzheimer's type cognitive dysfunction was induced in groups B to E by administering intraperitoneally, 1 mg/kg body weight of scopolamine for seven days before Donepezil and the aqueous extract of Telfairia occidentalis seeds for fourteen days. Twenty-four hours after the last administration, the animals were sacrificed; their brain tissues perfused and stained with glial fibrillary acidic protein (GFAP) dye. Results revealed prominently stained astrocytes with their processes intact (group A). Some densely stained numerous astrogliosis with hypertrophied fibres were noticed in group B. Group C demonstrated prominent astrocytes with hypertrophied fibres, group D, moderately stained astrogliosis with hypertrophied fibres while group E showed numerous astrocytes with prominent nuclei and hypertrophied fibres. In conclusion, there was reduced hippocampal astrogliosis mostly in group D treated with Telfairia occidentalis which may neutralize oxidative stress and enhanced learning and memory in the Wistar rats of the present study.

Effects of scopolamine treatment and consequent convulsion development in c‑fos expression in fed, fasted, and refed mice

Fasting, anticholinergics, and seizures affect c‑fos activation in the brain. Additionally, antimuscarinic treated fasted animals develop convulsion soon after re‑feeding. Therefore, we assessed whether c‑fos expression changes in fed, fasting, and refed animals and how scopolamine treatment affects these changes. We further assessed whether there is a change in c‑fos expression after convulsions. For this purpose, BALB/c mice fasted for 1, 3, 6, 12, 24 and 48 h periods were used. The animals were treated with saline or scopolamine. Half\r\nof the animals treated with saline or scopolamine were given food 20 min after injection. All animals were observed for development of convulsions for 30 min. At the end of this period, the brains of all animals were removed, and the percentage of c‑fos active cells in the hypothalamus was determined immunohistochemically. Convulsions occurred within 1‑48 h of fasting, after scopolamine treatment and re‑feeding. Compared to fed animals, c‑fos expression was not significantly changed in those undergoing different fasting periods, but significantly decreased after 12 h fasting. After animals were allowed to eat, c‑fos activation significantly increased in the 1, 3, 6 and 12 refed‑saline groups and decreased in the 48 refed‑saline group. Scopolamine treatment in 1‑24 h fasted animals increased c‑fos expression, but decreased in 48 h fasted animals. Whereas convulsion development in scopolamine‑treated 3, 6, 12 and 24 h refed animals suppressed c‑fos expression. These results demonstrate that re‑feeding and scopolamine treatment induces neuronal activity in the hypothalamus, while scopolamine induced convulsions after food intake suppressed the c‑fos activity.

Alpha lipoic acid ameliorates scopolamine induced memory deficit and neurodegeneration in the cerebello-hippocampal cortex

Scopolamine- induced memory loss is used to study new drug discovery in Alzheimer's disease (AD) pathogenesis. This study was aimed at evaluating the role of an antioxidant supplement alpha-lipoic acid (AHA), in ameliorating the oxidative damaging effects of scopolamine on cognition, memory, and the neurohistology of the cerebello-hippocampal cortex. Twenty adult male Wistar rats used were categorized into four (4) groups (n = 5): Group A- Control, Group B- 200 mg/kg of AHA, Group C- Scopolamine (memory-impaired model), and Group D- Neurodegenerative repair model (Scopolamine + AHA). The treatment lasted for fourteen (14) days. Y-maze and hang-wire (limb use test) were used as behavioural index to assess memory and motor function while brain tissues were processed for histology (H and E stain), histochemistry using Cresyl Fast violet stain for Nissl bodies, and immunohistochemistry of astrocytes using glial fibrillary acidic protein (GFAP). Results showed that scopolamine led to a decline in brain weight, impaired memory and motor function, induced oxidative tissue damage cumulating in loss of neuronal cells, chromatolysis, the proliferation of reactive astrocytes (neuroinflammation biomarker) in the cerebello-hippocampal cortex; but upon administration of AHA these neuropathological characterizations were inhibited and reversed by AHA demonstrating its antioxidant and neuro- repair potential. In conclusion, AHA is a useful therapeutic agent against scopolamine-induced cognitive and memory deficit because it has the ability to ameliorate oxidative tissue damage by attenuating reactive astrocytes proliferation and neuron chromatolysis thereby improving memory and motor function.

Dietary n-3 PUFA Deficiency Increases Vulnerability to Scopolamine-Induced Cognitive Impairment in Male C57BL/6 Mice

BACKGROUND

DHA (22:6n-3), a long-chain n-3 PUFA, is essential for normal brain development and function. Our previous study demonstrated that DHA significantly improves scopolamine-induced dementia. However, there are no reports on the relation between n-3 PUFA deficiency and scopolamine-induced cognitive impairment.

OBJECTIVES

The aim of this study was to evaluate whether n-3 PUFA deficiency increases vulnerability to scopolamine-induced cognitive impairment.

METHODS

Male and female C57BL/6 mice were mated and fed an n-3 PUFA-adequate [containing 2.88% α-linolenic acid (ALA; 18:3n-3)] or -deficient (containing 0.09% ALA) diet for 2 consecutive generations. The corresponding second-generation male offspring were kept on the same diet as their mothers after weaning, and were randomly assigned to 2 subgroups at 7 wk of age, in which they were intraperitoneally injected with saline [fed n-3 PUFA-adequate (Con) or -deficient (Def) diet] or scopolamine [5 mg/kg body weight; fed n-3 PUFA-adequate (Sco) or -deficient (Def + Sco) diet] once per day for 7 d before killing. Behavioral performance was analyzed using the Morris Water Maze test. Fatty acid composition, protein expression, and indicators of cholinergic and oxidative stress in the brain were measured.

RESULTS

The Def group showed lower brain DHA (-63.7%, P ≤ 0.01) and higher n-6 PUFA (+65.5%, P ≤ 0.05) concentrations than the Con group. The Def + Sco group and the Sco group showed poorer spatial learning and memory (escape latency on the sixth day: +60.3% and +36.8%; platform crossings: -43.9% and -28.2%, respectively) and more obvious cholinergic dysfunction (acetylcholine: -47.6% and -27.7%, respectively), oxidative stress (glutathione peroxidase: -64.2% and -32.5%, respectively), apoptosis [B-cell lymphoma 2 (BCL2)-associated X protein/BCL2: +230.8% and +153.8%; phosphorylated P38/P38: +232% and +130%, phosphorylated c-Jun N-terminal kinase (JNK)/JNK: +104.5% and +58.8%, respectively], neuroinflammation (IL-1β: +317.6% and +95%, respectively), and neurodevelopmental delay (brain-derived neurotrophic factor: -54.4% and -7.25%, respectively) than their corresponding saline-treated controls.

CONCLUSIONS

Dietary n-3 PUFA deficiency significantly decreases brain DHA concentrations and increases vulnerability to scopolamine-induced cognitive impairment in C57BL/6 male mice.

Trichoderma reesei fungal degradation boosted the potentiality of date pit extract in fighting scopolamine-induced neurotoxicity in male rats

Date pits are nutritious by-products, containing high levels of indigestible carbohydrates and polyphenols. To maximize the biological effects of the active ingredients, the hard shell of the polysaccharide must be degraded. Therefore, the current study aimed to assess the protective potentials of date pits extract (DP) and fungal degraded date pits extract (FDDP) against scopolamine (SCO)-induced neurodegeneration in male rats. Date pits were subjected to fungal degradation and extraction, followed by the measurement of phytochemicals and free radical scavenging activities. Forty-two adult Sprague-Dawley male rats were divided into seven groups: three control groups administered with either saline, DP or FDDP; four groups with neurodegeneration receiving SCO (ip 2 mg/kg/day, SCO group) with no treatment, SCO with DP (oral 100 mg/kg/day, DP + SCO group), SCO with FDDP (oral, 100 mg/kg/day, FDDP + SCO group), and SCO with donepezil (DON, oral, 2.25 mg/kg/day, DON + SCO group). The treatment duration was 28 days, and in the last 14 days, SCO was administered daily. Morris water maze test, acetylcholine esterase activity, oxidative stress, markers of inflammation and amyloidogenesis, and brain histopathology were assessed.

Protective effects of vitamin D on learning and memory deficit induced by scopolamine in male rats: the roles of brain-derived neurotrophic factor and oxidative stress

The beneficial effects of vitamin D (vit D) on central nervous system disorders have been suggested. In the current research, the protective effects of vit D on learning and memory deficit induced by scopolamine, oxidative stress criteria, brain-derived neurotrophic factor (BDNF), and nitric oxide (NO) in the brain were investigated. Rats were divided into five groups, including (1) Control, (2) Scopolamine (2 mg/kg), (3-5) Scopolamine + Vit D (100, 1000, and 10,000 IU/kg) groups. Vit D administrated for 2 weeks and in the third week scopolamine co-administrated with vit D and behavioral tests, including Morris water maze (MWM) and passive avoidance (PA) tests, were carried out. The cortical and hippocampal tissues were analyzed for BDNF, catalase (CAT), and superoxide dismutase (SOD) activities, thiol content, NO metabolites, and malondialdehyde (MDA) concentration. Scopolamine injection significantly impaired rats' performance on the MWM and PA test. It further enhanced the MDA and nitrite level while decreased thiol content and BDNF levels and SOD and CAT activities in the brain. Administration of both 1000 and 10,000 IU/kg vit D improved cognitive outcome in MWM and PA tests. In addition, vit D elevated thiol content, SOD and CAT activities, and BDNF levels, while reduced nitrite and MDA concentration. Vit D also increased the levels of vit D and calcium in the serum. The results demonstrated that vit D has protective effects on scopolamine-associated learning and memory impairment by improving BDNF levels and attenuating NO and brain tissue oxidative damage.

Central administration of afzelin extracted from Ribes fasciculatum improves cognitive and memory function in a mouse model of dementia

Neurodegenerative disorders are characterized by the decline of cognitive function and the progressive loss of memory. The dysfunctions of the cognitive and memory system are closely related to the decreases in brain-derived neurotrophic factor (BDNF) and cAMP response element-binding protein (CREB) signalings. Ribes fasciculatum, a medicinal plant grown in diverse countries, has been reported to pharmacological effects for autoimmune diseases and aging recently. Here we found that afzelin is a major compound in Ribes fasciculatum. To further examine its neuroprotective effect, the afzelin (100 ng/µl, three times a week) was administered into the third ventricle of the hypothalamus of C57BL/6 mice for one month and scopolamine was injected (i.p.) to these mice to impair cognition and memory before each behavior experiment. The electrophysiology to measure long-term potentiation and behavior tests for cognitive and memory functions were performed followed by investigating related molecular signaling pathways. Chronic administration of afzelin into the brain ameliorated synaptic plasticity and cognitive/memory behaviors in mice given scopolamine. Studies of mice's hippocampi revealed that the response of afzelin was accountable for the restoration of the cholinergic systems and molecular signal transduction via CREB-BDNF pathways. In conclusion, the central administration of afzelin leads to improved neurocognitive and neuroprotective effects on synaptic plasticity and behaviors partly through the increase in CREB-BDNF signaling.

Potentiation of anti-Alzheimer activity of curcumin by probiotic Lactobacillus rhamnosus UBLR-58 against scopolamine-induced memory impairment in mice

Curcumin, a major component of Indian saffron through clinical studies, revealed its neuroprotective effect in neurodegenerative diseases. However, it has not been utilized alone orally due to its low bioavailability. There are certain strategies to overcome the drawbacks such as poor absorption and low aqueous solubility. Many strategies are utilized to increase the systemic availability of curcumin. Among them, the steady intestinal and liver metabolism of curcumin by a curcumin adjuvant (enzyme inhibitor/inducer) is an important and less engrossed strategy for improving the overall systemic bioavailability of curcumin. Here, we assess the effect of probiotic Lactobacillus rhamnosus as a curcumin adjuvant (potentiate the effect of curcumin) in scopolamine-induced dementia in mice. To induce amnesia, scopolamine was used in a mouse model (1 mg/kg, daily for 10 days i.p.). After execution of behavioural tests (Morris water maze test), brains and liver were isolated for further neurochemical and histopathology examination. Our results showed a significant increase in antioxidant enzyme levels in curcumin with a probiotic group compared with curcumin alone. Besides, histopathology study results showed less neuronal damage of curcumin with probiotics as compared with the curcumin and scopolamine alone groups. Additionally, curcumin with probiotics improved memory and cognitive functions in the behavioural study with the significance of p ≤ 0.0001. In conclusion, curcumin with probiotics has greater activity as compared with curcumin alone and reverses the hallmarks of Alzheimer's disease (AD).

NFE2L2 activator RS9 protects against corneal epithelial cell damage in dry eye models

Oxidative stress may cause ocular surface damage during the development of dry eye. Mammalian cells have defense systems against oxidative stress. A central regulator of the stress response is nuclear factor-erythroid 2-related factor 2 (NFE2L2). NFE2L2 is activated by the novel triterpenoid RS9 (a biotransformation compound of RTA 402). The purpose of this study was to assess the efficacy of RS9 against dry eye using in vitro and in vivo models. Bioactivity was estimated by the induction of mRNAs for two NFE2L2-targeted genes: NQO1 (prevents radical species) and GCLC (glutathione synthesis), using a corneal epithelial cell line (HCE-T). Protection against oxidation and cell damage was tested in vitro by culturing cells under hyperosmotic stress or by the addition of menadione, a generator of reactive oxygen species (ROS). Dry eye in vivo was induced by the injection of scopolamine into rats. Then, 930 nM of RS9 was applied to both eyes for 2 weeks. Oxidative stress was measured by the accumulation of 8-hydroxy-2’-deoxyguanosine (8-OHdG). Corneal wound healing was measured by scoring for superficial punctate keratitis (SPK). Corneal epithelial cell densities were evaluated histologically. RS9 and RTA 402 induced the expression of NQO1 and GCLC mRNAs in HCE-T cells. And both compounds suppressed hyperosmotic-ROS generation and menadione induced cellular damage. However RS9 had a stronger protective effect than RTA 402. Ocular instillation of RS9 also significantly upregulated the expression of Nqo1 mRNA in the corneal epithelium. Accumulation of 8-OHdG, increase of SPK scores and decrement of basal cell density were observed in corneal epithelium from scopolamine-injected rats. These changes were significantly ameliorated by the topical administration of RS9. RS9 induced Nfe2l2 activation and Nfe2l2-targeted genes, reduced oxidation, and ameliorated symptoms of dry eye using in vitro and in vivo models. Thus, RS9 might be a potent candidate agent against dry eye disease.

The effects and mechanisms of the action of galangin on spatial memory in rats

BACKGROUND

Galangin, a flavonoid compound with acetylcholinesterase inhibitory activity, may improve cognitive functions by enhancing cholinergic transmission.

OBJECTIVES

We aimed to investigate the effects of galangin on spatial memory impairment in rats.

METHODS

The effects of galangin (50 and 100 mg/kg) and reference anti-dementia drug donepezil (1mg/kg) administrations were examined on memory impairment induced by the muscarinic cholinergic receptor antagonist scopolamine or the nicotinic cholinergic receptor antagonist mecamylamine in the Morris water maze (MWM) test. Hippocampal acetylcholine concentrations were also determined.

RESULTS

Galangin 50 and 100 mg/kg significantly decreased the mean distance to platform and increased the time spent in the escape platform quadrant in scopolamine-treated rats. Galangin 100 mg/kg significantly decreased the mean distance to platform and increased the time spent in the escape platform quadrant in mecamylamine-treated rats. The effects of galangin in the MWM were comparable with donepezil. Scopolamine and mecamylamine decreased acetylcholine concentrations, whereas galangin both alone and with mecamylamine or scopolamine administration increased acetylcholine concentrations.

CONCLUSION

Galangin improved memory impairment comparable to donepezil and nicotinic and muscarinic receptors may be involved in this effect. Galangin may be considered as a promising flavonoid in the prevention and treatment of memory impairment in Alzheimer's disease and other dementias (Fig. 7,Ref. 37).

Ameliorative effect of deoxyvasicine on scopolamine-induced cognitive dysfunction by restoration of cholinergic function in mice

BACKGROUND

Aerial parts of Peganum harmala Linn is used as a traditional medical herb for treatment of amnesia in Uighur medicine in China. Deoxyvasicine (DVAS) is one of the chief active ingredients in P. harmala, it possesses strong acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities in vitro, but the therapeutic effect and mechanisms on amnesia in vivo are unclear.

PURPOSE

The objective of this study was to investigate the improvement effect of DVAS from P. harmala in learning and memory deficits of scopolamine-induced mice and elucidate the underlying mechanisms involved.

METHODS

Mice were pretreated with DVAS (5, 15 and 45 mg/kg) and huperzine-A (0.2 mg/kg) by gavage for 7 days, and subsequently were daily intraperitoneally injected with scopolamine (1 mg/kg) to induce learning and memory deficits and behavioral performance was assessed by Morris water maze. To further evaluate the potential mechanisms of DVAS in improving learning and memory capabilities, pathological change, levels of various biochemical markers and protein expressions related to cholinergic system, oxidative stress, and neuroinflammation were examined.

RESULTS

The results showed that DVAS could alleviate learning and memory deficits in scopolamine-treated mice. DVAS could regulate cholinergic function by inhibiting AChE and activating choline acetyltransferase (ChAT) activities and protein expressions. DVAS could induce brain-derived neurotrophic factor and protect hippocampal pyramidal cells against neuronal damage. DVAS also enhanced antioxidant defense via increasing the antioxidant enzyme level and activity of glutathione peroxidase, and anti-inflammatory function through suppressing tumor necrosis factor-α. Additionally, DVAS could regulate the neurotransmitters by elevating acetylcholine, 5-hydroxytryptamine, γ-aminobutyric acid and reducing 5-hydroxyindole-3-acetic acid and glutamic acid.

CONCLUSION

Results illustrated that DVAS may be a promising candidate compound against amnesia via restoration of cholinergic function, regulating neurotransmitters, attenuating neuroinflammation and oxidative stress.

Neuroprotective Effects of Red Ginseng Saponins in Scopolamine-Treated Rats and Activity Screening Based on Pharmacokinetics

Ginseng has been used to alleviate age-related dementia and memory deterioration for thousands of years. This study investigated the protective effect of red ginseng saponins against scopolamine-induced cerebral injury. Meanwhile, pharmacokinetics of ginsenosides in normal and scopolamine-treated rats were compared. After scopolamine injection, glutathione, catalase and superoxide dismutase levels were significantly decreased when compared with control group. Compared with SA group, pretreatment of rats with red ginseng saponins could increase glutathione, catalase and superoxide dismutase level. Treatment with red ginseng saponins significantly decreased malondialdehyde level. In the pharmacokinetic analysis, a pattern recognition analysis method was used to investigate the pharmacokinetics of the absorbed compounds in blood. The pharmacokinetic parameters of Rg1, Rg2, Rh3, Rg5 and Rk1 in model group had higher area under the curve (AUC), mean residence time (MRT) and peak plasma concentration (Cmax) values; area under the curve (AUC) values and peak plasma concentration (Cmax) of model group was significantly different from that of normal group (p < 0.05). The Cmax value of Rk3, Rh1, Rh2 and Rh4 in model group was higher than normal group, but their AUC values were not significantly different. There was no significantly difference in time at Cmax (Tmax), AUC and Cmax values of Rb1, Rb2 Re, Rc, Rd and Rf between the model and normal group. 16 ginsenosides were grouped into three separate clusters according to principal component analysis (PCA) score plot based on pharmacokinetic data. The results suggested red ginseng saponins have significant protective effect against scopolamine-induced memory deficit and scopolamine-induced rats could lead to the changes of pharmacokinetic behaviors of ginsenosides.

Agathisflavone isolated from Schinus polygamus (Cav.) Cabrera leaves prevents scopolamine-induced memory impairment and brain oxidative stress in zebrafish (Danio rerio)

BACKGROUND

Agathisflavone, a biflavonoid isolated from Schinus polygamus (Cav.) Cabrera leaves been reported to promote various biological activities such as anti-inflammatory properties, promoting cognition and preventing cancer, antioxidant and antiapoptotic activities.

PURPOSE

Here, we tested the hypothesis whether anxiety, amnesia, and brain oxidative stress induced by scopolamine could be counteracted in zebrafish model by agathisflavone and tried to ascertain the underlying mechanism.

METHODS

Agathisflavone (1, 3 and 5 µg/l) was administered by immersion to zebrafish once daily for 8 days period. Anxiety and memory impairment were induced with scopolamine (100 µM) and measured with the novel tank diving test (NTT) and the Y-maze test. Zebrafish were divided into seven groups (n = 20/group): first group - control, second group - scopolamine (100 μM), the third, fourth and fifth group - agathisflavone treatment groups (FAB, 1 µg/l, 3 µg/l, and 5 µg/l), the sixth group - imipramine (IMP, 20 mg/l, as the positive control in NTT test), and the seventh group - donepezil group (DP, 10 mg/l, as the positive control in Y-maze test). The identification of the agathisflavone was done by spectroscopy, and the structure of the compound was confirmed by (-) Electrospray Ionisation Mass Spectrometry (ESI-MS). The brain oxidative status and acetylcholinesterase (AChE) activity were also investigated.

RESULTS

Agathisflavone from Schinus polygamus (Cav.) Cabrera leaves was identified. Also, we demonstrated that agathisflavone significantly reversed scopolamine-induced behavioral score alteration in the NTT and Y-maze tests. Consequently, agathisflavone promoted inhibition of AChE activity and restored the brain antioxidant status.

CONCLUSION

Our results demonstrate that agathisflavone promotes brain antioxidant action and ameliorates scopolamine-induced anxiety and memory deficits in zebrafish.

Effect of hydroalcoholic Echium amoenum extract on scopolamine-induced learning and memory impairment in rats

CONTEXT

Scopolamine, a muscarinic receptor antagonist, causes memory loss that resembles Alzheimer's disease (AD). Echium amoenum L. (Boraginaceae) is a famous medicinal plant of Iran that is traditionally used as a sedative and mood enhancer.

OBJECTIVE

This study evaluates the effect of hydroalcoholic extract of E. amoenum flowers on scopolamine-induced memory impairment in rats.

MATERIALS AND METHODS

Fifty male Wistar rats were randomly divided into five groups. Control group received normal saline, model group received scopolamine (0.7 mg/kg, IP, daily for 21 days), and test groups received E. amoenum extract (50, 75, and 100 mg/kg, IP, daily for 21 days) 30 min before each scopolamine injection. The elevated plus maze (EPM), shuttle box, novel object and rotarod tests were performed after treatment. Brain levels of malondialdehyde (MDA) and total antioxidant capacity (TCA) were also determined.

RESULTS

Scopolamine-treated rats spent more time exploring the novel object compared to the control, and E. amoenum extract at all three doses significantly decreased the time spent exploring the novel object (p < 0.05). E. amoenum extract (75 and 100 mg/kg) significantly elongated the secondary latency in rats receiving scopolamine in the shuttle box test (p < 0.05). In addition, treatment with 75 and 100 mg/kg doses of E. amoenum extract significantly ameliorated scopolamine-induced motor in coordination in rotarod test (p < 0.05). It also significantly increased the time spent in the open arms and reduced the time spent in the closed arms of EPM (p < 0.05). Treatment of scopolamine-exposed rats with E. amoenum extract significantly increased TCA and reduced MDA level of brain (p < 0.05).

DISCUSSION AND CONCLUSIONS

E. amoenum extract shows protective effect against scopolamine-induced impairment and is suggested to be tested in clinical trials to evaluate the efficacy on AD.

Phencyclidine and Scopolamine for Modeling Amnesia in Rodents: Direct Comparison with the Use of Barnes Maze Test and Contextual Fear Conditioning Test in Mice

Nowadays cognitive impairments are a growing unresolved medical issue which may accompany many diseases and therapies, furthermore, numerous researchers investigate various neurobiological aspects of human memory to find possible ways to improve it. Until any other method is discovered, in vivo studies remain the only available tool for memory evaluation. At first, researchers need to choose a model of amnesia which may strongly influence observed results. Thereby a deeper insight into a model itself may increase the quality and reliability of results. The most common method to impair memory in rodents is the pretreatment with drugs that disrupt learning and memory. Taking this into consideration, we compared the activity of agents commonly used for this purpose. We investigated effects of phencyclidine (PCP), a non-competitive NMDA receptor antagonist, and scopolamine (SCOP), an antagonist of muscarinic receptors, on short-term spatial memory and classical fear conditioning in mice. PCP (3 mg/kg) and SCOP (1 mg/kg) were administrated intraperitoneally 30 min before behavioral paradigms. To assess the influence of PCP and SCOP on short-term spatial memory, the Barnes maze test in C57BL/J6 mice was used. Effects on classical conditioning were evaluated using contextual fear conditioning test. Additionally, spontaneous locomotor activity of mice was measured. These two tests were performed in CD-1 mice. Our study reports that both tested agents disturbed short-term spatial memory in the Barnes maze test, however, SCOP revealed a higher activity. Surprisingly, learning in contextual fear conditioning test was impaired only by SCOP.

Graphical Abstract

Ebselen inhibits the activity of acetylcholinesterase globular isoform G4 in vitro and attenuates scopolamine-induced amnesia in mice

There is a well-known relationship between the cholinergic system and learning, memory, and other common cognitive processes. The process for researching and developing new drugs has lead researchers to repurpose older ones. This study investigated the effects of ebselen on the activity of acethylcholinesterase (AChE) isoforms in vitro and in an amnesia model induced by scopolamine in Swiss mice. In vitro, ebselen at concentrations equal or higher than 10 μM inhibited the activity of cortical and hippocampal G4/AChE, but not G1/AChE isoform. Treatment of mice with ebselen (50 mg/kg, i.p.) was effective against impairment of spatial recognition memory in both Y-maze and novel object recognition tests induced by scopolamine (1 mg/kg, i.p.). Ebselen (50 mg/kg) inhibited hippocampal AChE activity in mice. The present study demonstrates that ebselen inhibited the G4/AChE isoform in vitro and elicited an anti-amnesic effect in a mouse model induced by scopolamine. These findings reveal ebselen as a potential compound in terms of opening up valid therapeutic avenues for the treatment of memory impairment diseases.

Dietary Supplementation of Almond Prevents Oxidative Stress by Advocating Antioxidants and Attenuates Impaired Aversive Memory in Male Rats

Scopolamine, an anti-muscarinic agent, has been shown to induce amnesia and oxidative stress similar to that observed in the older age. The present study was designed to determine the relationship between the oxidative status and memory improvement in scopolamine injected rats pre-administered with almonds. Rats (n = 8) in the almond group were administered orally with 400 mg/kg almond suspension for 28 days daily before the intraperitoneal injection of scopolamine (0.5 mg/kg). Passive avoidance task (PAT) was used to assess memory function at the end of treatment. The present study revealed that scopolamine injection significantly impaired the memory function in rats pre-treated with saline which was accompanied by increased oxidative stress as evident by increased brain malondialdehyde (MDA) levels and reduced activities of antioxidant enzymes as compared to healthy controls. Pre-treatment with almond significantly ameliorated scopolamine-induced oxidative stress and memory dysfunction. These findings suggest that dietary supplementation with almonds may have a beneficial effect in reducing the risk of oxidative stress-induced memory loss and delaying or preventing the onset of age-related memory impairment.

Ethanol Extract of Oldenlandia diffusa Herba Attenuates Scopolamine-Induced Cognitive Impairments in Mice via Activation of BDNF, P-CREB and Inhibition of Acetylcholinesterase

Though Oldenlandia diffusa Herba (ODH) has been known to exhibit anti-cancer and anti-inflammatory effects, its anti-amnestic effect has never been reported so far. The aim of this present study was to elucidate the anti-amnestic effect of ODH. ODH pretreatment significantly reduced escape latency of scopolamine treated Institute of Cancer Research (ICR) mice compared to untreated control groups in a Morris water maze test. Similarly, the passive avoidance test showed that ODH treatment recovered the scopolamine induced amnesia in the ICR mouse model. Concentration of Ach in brains of ODH treated mice was increased compared to that of scopolamine treated mice. In addition, activity of acetylcholinesterase (AChE) was notably decreased by ODH. The protein expression of brain-derived neurotrophic factor (BDNF) and phospho-cAMP response element-binding protein (p-CREB) (Ser133) was increased in ODH pretreated group compared to control group. Consistently, immunohistochemistry (IHC) revealed the elevated expression of brain-derived neurotrophic factor (BDNF) and p-CREB in brains of ODH treated mice compared to the control group. Overall, these findings suggest that ODH has anti-amnestic potential via activation of BDNF and p-CREB and inhibition of AChE in mice with scopolamine induced amnesia.

Cognitive Improving Effects by Highbush Blueberry (Vaccinium crymbosum L.) Vinegar on Scopolamine-Induced Amnesia Mice Model

The present study aimed to evaluate the preventive effects of highbush blueberry (Vaccinium corymbosum L.) vinegar (BV) on cognitive functions in a scopolamine (Sco)-induced amnesia model in mice. In this study, Sco (1 mg/kg, intraperitoneal injection) was used to induce amnesia. ICR mice were orally administered donepezil (5 mg/kg), blueberry extract (120 mg/kg), and BV (120 mg/kg) for 7 days. After inducing cognitive impairment by Sco, a behavioral assessment using behavior tests (i.e., Y-maze and passive avoidance tests) was performed. The BV group showed significantly restored cognitive function in the behavioral tests. BV facilitated cholinergic activity by inhibiting acetylcholinesterase activity, and enhanced antioxidant enzyme activity. Furthermore, BV was found to be rehabilitated in the cornu ammonis 1 neurons of hippocampus. In our study, we demonstrated that the memory protection conferred by BV was linked to activation of brain-derived neurotrophic factor (BDNF)/cAMP response element binding protein (CREB)/serine-threonine kinase (AKT) signaling.

Phytochemical analysis, molecular docking and antiamnesic effects of methanolic extract of Silybum marianum (L.) Gaertn seeds in scopolamine induced memory impairment in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Silybum marianum (L.) Gaertn and its main component silymarin have been extensively studied and have been found effective in various neurological disorders.

AIMS OF THE STUDY

The aim of the current study is to identify phytoconstituents in the methanolic extract (Me. Ext) of Silybum marianum (L.) Gaertn seeds and to study in-vivo the anti-amnesic effects along with in vitro antioxidant and acetylcholinesterase (AChE) and buteryl cholinesterase (BChE) inhibition potential. Induced fir docking (IFD) results have confirmed that quercetin, morin and rutin showed good affinity when docked into AChE binding site.

MATERIALS AND METHODS

The present study investigates the in-vitro AChE and BChE inhibition potential of the Me-Ext of Silybum marianum (L.) Gaertn at various concentrations (31.25, 62.50, 125, 250, 500, 1000µg/mL) using Ellman's spectrophotometric analysis, while antioxidant potential against DPPH and ABTS were determined using Brand-Williams spectrophotometric method. Furthermore, the in-vivo anti-amnesic effects of Me. Ext at the dose level of 50, 100 and 200mg/kg were also evaluated using scopolamine -induced memory impairment in mice in the novel object recognition test (NORT) and Y-maze test.

RESULTS

The Me. Ext showed a concentration dependent inhibition of AChE and BChE with IC50 values of 110 and 130µg/mL respectively and antioxidant activity against DPPH and ABTS with IC50 values 280 and 220µg/mL, respectively. In mice, Me. Ext reversed the amnesia induced by scopolamine as indicated by a dose-dependent increase in spontaneous alternation performance in the Y-maze task (p< 0.05 versus scopolamine) and increase in the discrimination index in the NORT comparable to the standard drug donepezil 2mg/kg. HPLC-UV analysis showed the presence of quercetin, rutin and morin. Induced fit docking (IFD) was performed using quercetin, rutin and morin, Glide Gscore and IFD score of all compounds were consistent with their experimental AChE inhibitory activities.

CONCLUSION

The results indicate that Silybum marianum (L.) Gaertn could be a new source for the isolation of phytoconstituents useful in cognition and memory disorders such as Alzheimer's disease.

Persistent seizure control in epileptic mice transplanted with gamma-aminobutyric acid progenitors

OBJECTIVE

A significant proportion of the more than 50 million people worldwide currently suffering with epilepsy are resistant to antiepileptic drugs (AEDs). As an alternative to AEDs, novel therapies based on cell transplantation offer an opportunity for long-lasting modification of epileptic circuits. To develop such a treatment requires careful preclinical studies in a chronic epilepsy model featuring unprovoked seizures, hippocampal histopathology, and behavioral comorbidities.

METHODS

Transplantation of progenitor cells from embryonic medial or caudal ganglionic eminence (MGE, CGE) were made in a well-characterized mouse model of status epilepticus-induced epilepsy (systemic pilocarpine). Behavioral testing (handling and open field), continuous video-electroencephalographic (vEEG) monitoring, and slice electrophysiology outcomes were obtained up to 270 days after transplantation (DAT). Post-hoc immunohistochemistry was used to confirm cell identity.

RESULTS

MGE progenitors transplanted into the hippocampus of epileptic mice rescued handling and open field deficits starting at 60 DAT. In these same mice, an 84% to 88% reduction in seizure activity was observed between 180 and 210 DAT. Inhibitory postsynaptic current frequency, measured on pyramidal neurons in acute hippocampal slices at 270 DAT, was reduced in epileptic mice but restored to naïve levels in epileptic mice receiving MGE transplants. No reduction in seizure activity was observed in epileptic mice receiving intrahippocampal CGE progenitors.

INTERPRETATION

Our findings demonstrate that transplanted MGE progenitors enhance functional GABA-mediated inhibition, reduce spontaneous seizure frequency, and rescue behavioral deficits in a chronic epileptic animal model more than 6 months after treatment. Ann Neurol 2017;82:530-542.

Neuroprotective effect of Cubebin: A dibenzylbutyrolactone lignan on scopolamine-induced amnesia in mice

BACKGROUND & OBJECTIVES

Acetylcholinesterase (AChE) inhibitors represent a major class of drugs which provide symptomatic relief and improvement in cognitive function in Alzheimer's disease (AD). In this study, cubebin, a dibenzylbutyrolactone lignan, was isolated from Piper cubeba and investigated for its AChE inhibitory activity in an attempt to explore its potential for memory-enhancing activities in mice.

METHODS

Molecular docking of cubebin was carried out followed by in vitro AChE activity. Mice were treated with cubebin (25 & 50 mg/kg; i.p.), for three days and memory impairment was induced by scopolamine (3 mg/kg; i.p.). Memory function was evaluated by Morris water maze (MWM) test. Biochemical parameters of oxidative stress and cholinergic function were estimated in brain.

RESULTS

Molecular docking study revealed that cubebin was well bound within the binding site of the AChE enzyme showing interactions such as π-π stacking and hydrogen bonding with residues present therein. Cubebin inhibited AChE enzyme in an in vitro assay with IC50value of 992 μM. Scopolamine administration caused a significant impairment of learning and memory in mice, as indicated by a marked decrease in MWM performance. Scopolamine administration also produced a significant enhancement of brain AChE activity and oxidative stress in mice brain. Pre-treatment of cubebin (25 and 50 mg/kg; i.p.) significantly prevented scopolamine-induced learning and memory deficits along with attenuation of scopolamine-induced rise in brain AChE activity and oxidative stress level.

INTERPRETATION & CONCLUSIONS

Cubebin showed promising protective activity in scopolamine-induced spatial memory impairment in mice. This could be attributed to its brain AChE inhibition and antioxidant activity.

Label-free pharmacological profiling based on dynamic mass redistribution for characterization and authentication of hazardous natural products

Natural products are becoming increasingly popular in multiple fields involving medicines, foods and beverages. However, due to the frequent occurrence of poisoning incidents, their toxicity and safety have caused a serious concern. Here we report a method of biosensor-based two-phase pharmacological profiling (BTPP) for discovery, monitor and control of receptor-targeted natural products. BTPP uses a resonant waveguide grating biosensor for label-free and non-invasive detection of intracellular dynamic mass redistribution (DMR), a phenomenon caused by protein relocalization after receptors receiving stimulation from toxicants. The method can not only facilitate the identification of hazardous materials but also quantify their bioactivity by EC₅₀. As a proof of concept, the method was successfully applied to recognize Daturae Flos (DF), an herb that can antagonize muscarinic acetylcholine M₂ receptor and further cause poisoning, from other easily confused species. BTPP combined with high performance liquid chromatography revealed that scopolamine and hyoscyamine in DF were the key marker compounds. Moreover, the method accurately picked out 2 M₂ receptor antagonists from 25 natural compounds, displaying its potential in high-throughput screening. This study provides a systematic illustration about the establishment, applicability and advantages of BTPP, which contributes to the safety assessment of natural products in related fields.

Loganin enhances long-term potentiation and recovers scopolamine-induced learning and memory impairments

Although the incidence rate of dementia is rapidly growing in the aged population, therapeutic and preventive reagents are still suboptimal. Various model systems are used for the development of such reagents in which scopolamine is one of the favorable pharmacological tools widely applied. Loganin is a major iridoid glycoside obtained from Corni fructus (Cornusofficinalis et Zucc) and demonstrated to have anti-inflammatory, anti-tumor and osteoporosis prevention effects. It has also been found to attenuate Aβ-induced inflammatory reactions and ameliorate memory deficits induced by scopolamine. However, there has been limited information available on how loganin affects learning and memory both electrophysiologically and behaviorally. To assess its effect on learning and memory, we investigated the influence of acute loganin administration on long-term potentiation (LTP) using organotypic cultured hippocampal tissues. In addition, we measured the effects of loganin on the behavior performance related to avoidance memory, short-term spatial navigation memory and long-term spatial learning and memory in the passive avoidance, Y-maze, and Morris water maze learning paradigms, respectively. Loganin dose-dependently increased the total activity of fEPSP after high frequency stimulation and attenuated scopolamine-induced blockade of fEPSP in the hippocampal CA1 area. In accordance with these findings, loganin behaviorally attenuated scopolamine-induced shortening of step-through latency in the passive avoidance test, reduced the percent alternation in the Y-maze, and increased memory retention in the Morris water maze test. These results indicate that loganin can effectively block cholinergic muscarinic receptor blockade -induced deterioration of LTP and memory related behavioral performance. Based on these findings, loganin may aid in the prevention and treatment of Alzheimer's disease and learning and memory-deficit disorders in the future.

Benzoate fraction from Gentiana rigescens Franch alleviates scopolamine-induced impaired memory in mice model in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

G. rigescens Franch (Long Dan Cao in Chinese) is a well-known TCM herb. It is clinically used with other drugs for the treatment of brain diseases such as epilepsy, postherpetic neuralgia in China.

AIM OF STUDY

In our previous study, the 11 dihydroxybenzoates compounds with NGF mimicking activity from G. rigescens Franch were found. In the present study, the neurogenesis and neuroprotection of a mixture of benzoates ( n-GS) were investigated in animal level.

MATERIALS AND METHODS

The NGF mimicking activity of n-GS from G. rigescens Franch was examined in PC12 cells. The neurogenesis effects of n-GS were investigated in ICR mice with 5-bromo-2-deoxyuridine (BrdU) and neuronal neclei (NeuN) double immunostaining. Furthermore, the neuroprotection effects of n-GS on the memory in a scopolamine (SCO)-induced mouse model were evaluated with animal behavior tests.

RESULTS

The NGF-mimicking function and neurogenesis of n-GS were observed in PC12 cells and in normal mice. Subsequently, we investigated the effects of n-GS on the memory in a SCO-induced mouse model. In Y-maze test, SCO significantly lowered the alternation. This finding was reversed by n-GS and donepezil (DONE). SCO significantly impaired the mice's performance in novel object recognition (NOR) and Morris water maze (MWM) tests. The time spent to explore the novel object was longer in the n-GS- and DONE-treated groups than in the SCO control group. In the MWM test, the escape latency of n-GS- and DONE-treated groups was shorter than that of the SCO control group. Mechanism study showed that SCO significantly reduced superoxide dismutase (SOD) but increased the activities of acetylcholinesterase (AChE) and the levels of malondialdehyde (MDA) in the hippocampus and cerebral cortex, which all can be improved by n-GS and DONE. Additionally, the phosphorylation of type 1 insulin-like growth factor (IGF-1) receptor, extracellular signal-regulated kinase (ERK), and cAMP responsive element-binding (CREB) protein in the hippocampus was significantly up-regulated in the treatment group compared with that in the SCO group.

CONCLUSIONS

n-GS could alleviate impaired memory of the SCO-induced mice model by inhibiting AChE activity and oxidative stress, and regulating the IGF-1R/ERK signaling pathway.

Sesame indicum, a nutritional supplement, elicits antiamnesic effect via cholinergic pathway in scopolamine intoxicated mice

PURPOSE

Present study was undertaken to evaluate the antiamnesic effect of Sesamum indicum (S. indicum) seeds (standardized for sesamin, a lignan, content) in scopolamine, a muscarinic antagonist intoxicated mice.

METHODS

Male Swiss albino mice (18-22 g bw) were pretreated with methanolic extract of sesame seeds (MSSE) (100 and 200 mg/kg/day, p.o) for a period of 14 days. Scopolamine (0.3 mg/kg, i.p.) was injected on day 14, 45 ± 10 min after MSSE administration. Antiamnesic effect of MSSE was evaluated using step-down latency (SDL) on passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. To unravel the mechanism of action, we examined the effects of MSSE on the genes such as acetyl cholinesterase (AChE), muscarinic receptor M1 subtype (mAChRM₁ ), and brain derived neurotrophic factor (BDNF) expression within hippocampus of experimental mice. Further, its effects on bax and bcl-2 were also evaluated. Histopathological examination of hippocampal CA₁ region was performed using cresyl violet staining.

RESULTS

MSSE treatment produced a significant and dose dependent increase in step down latency in passive avoidance test and decrease in transfer latency in elevated plus maze in scopolamine intoxicated injected mice. MSSE down-regulated AChE and mAChRM₁ and up-regulated BDNF mRNA expression. Further, it significantly down-regulated the bax and caspase 3 and up-regulated bcl-2 expression in scopolamine intoxicated mice brains. Mice treated with MSSE showed increased neuronal counts in hippocampal CA₁ region when compared with scopolamine-vehicle treated mice.

CONCLUSION

Sesame seeds have the ability to interact with cholinergic components involved in memory function/restoration and also an interesting candidate to be considered for future cognitive research. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1955-1963, 2016.

Timosaponin B-II ameliorates scopolamine-induced cognition deficits by attenuating acetylcholinesterase activity and brain oxidative damage in mice

Timosaponin B-II (TB-II) is a main active saponin isolated from the rhizome of Anemarrhena asphodeloides Bge., which is widely used in traditional Chinese medicine. In this study, the effect of TB-II on learning and memory was investigated in a scopolamine-induced mouse model of Alzheimer's disease. The results of behavioral tests indicated that TB-II significantly increased the spontaneous alternation in the Y-maze test, and reversed the shortening of step-through latency induced by scopolamine in the passive avoidance test, showing protective effects on short-term and working memory. In the Morris water maze test, TB-II reduced the escape latency time in the training trial, and increased the swimming time in the target quadrant in the probe trial. Biochemical data demonstrated that TB-II significantly inhibited acetylcholinesterase (AChE) activity in the cerebral cortex and hippocampus of mice. Moreover, TB-II markably attenuated the reduction in glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities, and decreased malondialdehyde (MDA) levels, which are key biomarkers of brain oxidative stress. These results indicated that TB-II offers protection against scopolamine-induced deficits in learning and memory, possibly by inhibiting AChE and preventing oxidative stress damage. The findings suggested that TB-II has a potential therapeutic effect on cognitive and behavioral impairment.

Evaluation of potential antiamnesic activities of aqueous extract of Vitex trifolia leaves against scopolamine induced amnesia and in normal rats

BACKGROUND

The goal of this study was to evaluate the cerebroprotective and cognition-enhancing activities of the aqueous Vitex trifolia (Vt) L. (Verbenaceae) leaf extract against scopolamine-induced amnesia and in normal rats.

METHODS

Reference or working memory and long-term memory in rodents were tested by experimental paradigms like passive avoidance (PA) and T-maze (TM), respectively. TM and Morris water maze (MWM) were used to screen putative spatial or localization task and the navigation memory-enhancing activities of Vt extract, respectively. In both the PA and TM models, scopolamine (0.5 mg/kg, intraperitoneal, 30 min prior to the trial) was used to induce amnesia, and donepezil (3 mg/kg/day for 15 days) was used as a standard antiamnesic drug. In MWM, two doses of Vt extract were tested against normal control rats. The aqueous Vt extract was prepared as a suspension in 0.5% carboxymethyl cellulose and administered orally at two doses (10 and 20 mg/kg/day) for 15 days to the respective group of rats.

RESULTS

The higher dose (20 mg/kg) of plant extract exhibited significant (p<0.01) antiamnesic activity in the PA and TM models vs. the control. In the MWM test, at probe trial, Vt extract 20 mg/kg showed the least escape latency time, which was statistically significant (p<0.01) and exhibited maximum percentage of time spent in the probe quadrant by 60.75%.

CONCLUSIONS

These results partly substantiate the traditional use of Vt leaves for improvement of cognition, indicating that daily administration of Vt leaves differentially could modulate short- and long-term learning and memory in rats probably through its battery of anticholinesterase, procholinergic, anti-inflammatory, antioxidant, and neuroprotective activities.

Lactobacillus pentosus var. plantarum C29 increases the protective effect of soybean against scopolamine-induced memory impairment in mice

Biological activities of soybean saponins are dependent on their metabolism by gut microbiota, which generate absorbable bioactive metabolites. Therefore, to enhance the pharmacological effect of soybean, we fermented defatted soybean powder (SP) with Lactobacillus pentosus var. plantarum C29 and measured its protective effect against scopolamine-induced memory impairment in mice using the passive avoidance, Y-maze and Morris water maze tasks. Fermentation increased soyasapogenol B, genistein and daidzein content of soybean and enhanced the protective effect of soybean against scopolamine-induced memory impairment. Additionally, compared with the exthanol extract of soybean, fermented SP (FSP) increased the expression of brain-derived neurotrophic factor (BDNF) in the hippocampi of scopolamine-treated mice. Furthermore, FSP inhibited acetylcholinesterase (AChE) activity in vitro and ex vivo. These findings suggest that C29 fermentation might increase the ameliorating effect of soybean against memory impairments by inhibiting AChE activity and increasing BDNF expression.

Protection against brain tissues oxidative damage as a possible mechanism for the beneficial effects of Rosa damascena hydroalcoholic extract on scopolamine induced memory impairment in rats

OBJECTIVES

Hypnotic, analgesic, anticonvulsant, and antioxidant effects of Rosa damascena have been reported. This study, investigated the effect of R. damascena hydroalcoholic extract on memory performance in a scopolamine-induced memory impairment model.

METHODS

The rats were divided into control group received just saline; scopolamine group was treated by saline for 2 weeks, but was injected by scopolamine 30 minutes before each trial in Morris water maze test; treatment groups (scopolamine + extract 50; Sco + Ext 50) and (scopolamine + extract 250; Sco + Ext 250) were daily treated by 50 and 250 mg/kg of R. damascena extract (2 weeks) and were finally injected by scopolamine before each trial in Morris water maze. The brains were removed for biochemical measurements.

RESULTS

Time latency and path length in the scopolamine group were higher than control (P < 0.01 to <0.001). Both treatment groups showed shorter traveled distance and time latency compared with scopolamine group (P < 0.05 to <0.001). Time spent in target quadrant by scopolamine group was lower than control (P < 0.05), while Sco + Ext 250 group spent longer time in target quadrant than scopolamine group (P < 0.05). Malondialdehyde concentrations in hippocampal and cortical tissues of scopolamine group were higher, while thiol concentrations were lower than control ones (P < 0.001). Treatment by both doses of the extract decreased the malondialdehyde concentration, while increased the thiol concentration (P < 0.05 to <0.001).

DISCUSSION

The results of this study showed that the hydroalcoholic extract of R. damascena prevents scopolamine-induced memory deficits. This finding suggests that memory improvement may be in part due to the antioxidant effects.

[Effect of dopamine receptor agonist apomorphine on scopolamine induced memory deficits in mice]

OBJECTIVE

To research the mechanism of dopamine (DA) controlled memory in mice.

METHODS

Mice received i.p. injection of scopolamine (0.3 mg/kg, SCOP 0.3, and 3.0mg/kg, SCOP 3.0, respectively, n = 10) and saline (NS, n = 10) for 60 days in experiment 1. Memory of mice was detected by dark avoidance behavior in the 53" d and the 60"' d. Animals were sacrificed after the memory test; brain tissues were processed for Fos-ir and TH-ir by immunohistochemistry. Mice were divided into four groups according results of expri-ment 1, they received i.p. injection of apomorphine (0.1 mg/kg, APO 0.1, 0.5 mg/kg, APO 0.5, and 2.0 mg/kg, APO2.0 respectively, n = 10).

RESULTS

Memory was inhibited in mice injected scopolamine 3.0 mg/kg. Latency was significantly less than in NS group, only 1/ 4 that of NS group (P > 0.05). The number of mistake of SCOP 3.0 group increased about four times than that of NS group (P > 0.05). But there was no difference of latency and number of mistake between SCOP 0.3 and NS group in expriment 1. Scopolamine-induced memory deficit was associated with decreased cellular activation, indicated by Fos immunoreactive (ir) staining, in NAcc CA1 and CA3 (P < 0.05), and also associated with decreases in the number of cells labeled for tyrosine hydroxylase (TH-ir), the rate limiting enzyme for dopamine conversion (P < 0.01) and the number of cells co-labeled for TH-ir/Fos-ir (P <0.01) in the ventral tegmental area(VTA), apomorphine lessened scopolamine-induced memory deficit in experiment 2. The number of cells co-labeled for TH-ir/Fos-ir (P <, 0.05) was increased in VTA after apomorphine treatment.

CONCLUSION

Apomorphine lessened scopolamine-induced memory deficit in mice by increasing DA activities in VTA.

Total isoflavones from soybean and tempeh reversed scopolamine-induced amnesia, improved cholinergic activities and reduced neuroinflammation in brain

The present study was undertaken to compare the neuroprotective effects between total isoflavones from soybean and tempeh against scopolamine-induced cognitive dysfunction. Total isoflavones (10, 20 and 40mg/kg) from soybean (SI) and tempeh (TI) were administered orally to different groups of rats (n=6) for 15days. Piracetam (400mg/kg, p.o.) was used as a standard drug while scopolamine (1mg/kg, i.p.) was used to induce amnesia in the animals. Radial arm and elevated plus mazes served as exteroceptive behavioural models to measure memory. Brain cholinergic activities (acetylcholine and acetylcholinesterase) and neuroinflammatory activities (COX-1, COX-2, IL-1β and IL10) were also assessed. Treatment with SI and TI significantly reversed the scopolamine effect and improved memory with TI group at 40mg/kg, p.o. exhibiting the best improvement (p<0.001) in rats. The TI (10, 20 and 40mg/kg, p.o.) significantly increased (p<0.001) acetylcholine and reduced acetylcholinesterase levels. Meanwhile, only a high dose (40mg/kg, p.o.) of SI showed significant improvement (p<0.05) in the cholinergic activities. Neuroinflammation study also showed that TI (40mg/kg, p.o.) was able to reduce inflammation better than SI. The TI ameliorates scopolamine-induced memory in rats through the cholinergic neuronal pathway and by prevention of neuroinflammation.

Learning and memory promoting effects of crude garlic extract

Chronic administration of aged garlic extract has been shown to prevent memory impairment in mice. Acute and chronic (21 days) effects of marketed formulation of crude garlic extract (Lasuna) were evaluated on learning and memory in mice using step down latency (SDL) by passive avoidance response and transfer latency (TL) using elevated plus maze. Scopolamine (0.4 mg/kg, ip) was used to induce amnesia in mice and piracetam (200 mg/kg, ip) served as positive control. In the acute study, Lasuna (65 mg/kg, po) partially reversed the scopolamine-induced amnesia but failed to improve learning and memory in untreated animals. Chronic administration of Lasuna (40 mg/kg/day for 21 days) significantly improved learning both in control and scopolamine induced amnesic animals. Influence of Lasuna on central cholinergic activity and its antioxidant properties were also studied by estimating the cortical acetylcholinesterase (AchE) activity and reduced glutathione (GSH) levels respectively. Chronic administration of Lasuna inhibited AchE, while increasing GSH levels. Thus the results indicate that long-term administration of crude garlic extract may improve learning and memory in mice while the underlying mechanism of action may be attributed to the anti-AchE activity and anti-oxidant property of garlic.

The effects of Zibu Piyin Recipe components on scopolamine-induced learning and memory impairment in the mouse

ETHNOPHARMACOLOGICAL RELEVANCE

The Zibu Piyin Recipe (ZBPYR) is derived from Zicheng Decoction, a traditional Chinese medicine formula recorded in the book of Bujuji, written by Wu Cheng in the Qing dynasty and used for clinical treatment of amnesia. Our aim was to study the effects of Zibu Piyin Recipe (ZBPYR) fractions on scopolamine-induced learning and memory impairment in the mouse.

MATERIALS AND METHODS

Crude extracts were prepared using various solvents, and individual fractions produced following D101 macroporous resin column chromatography. The passive avoidance task, step down test and Morris water maze test were then performed in mice for the evaluation of learning and memory alterations. The effective fractions were then analyzed using GC-MS and polysaccharide measurement methods, respectively.

RESULTS

The treatment group latency for the alcohol precipitation from water part (EP) and 95% ethanol part (95%E) following D101 macroporous resin column chromatography was significantly prolonged when compared to that of the scopolamine treated groups for both the passive avoidance task and step down test. In the Morris water maze tests, treatment with EP and 95%E resulted in a significantly shorter escape latency time (from the fourth day and the second day) and swimming distance (on the third day and from the third day) in scopolamine-induced mice. In the memory retention test, treatment with EP and 95%E dramatically shortened the latency to cross platform location and increased the numbers of platform location crosses in the scopolamine-induced mice. The polysaccharide content in EP was determined to be 69.79%. The 95%E was found to mainly contain asarone, α-cadinol, isocalamendiol, 2,4,7,14-tetramethyl-4-vinyl-tricyclo[5.4.3.0(1,8)]tetradecan-6-ol, 3-isopropyl-6,7-dimethyltricyclo[4.4.0.0(2,8)]decane-9,10-diol, 2-methyl-9-(prop-1- -en-3-ol-2-yl)-bicyclo[4.4.0]dec-2-ene-4-ol, diepicedrene-1-oxide, 7-methoxy-6-(3- -methyl-2-oxobutyl)-2H-1-benzopyran-2-one and diisooctyl phthalate when assessed using GC-MS analysis.

CONCLUSION

These findings suggest that the polysaccharide and volatile oil present in ZBPYR exhibit ameliorating effects on scopolamine-induced memory dysfunction.

D-cycloserine in prelimbic cortex reverses scopolamine-induced deficits in olfactory memory in rats

A significant interaction between N-methyl-D-aspartate (NMDA) and muscarinic receptors has been suggested in the modulation of learning and memory processes. The present study further investigates this issue and explores whether d-cycloserine (DCS), a partial agonist at the glycine binding site of the NMDA receptors that has been regarded as a cognitive enhancer, would reverse scopolamine (SCOP)-induced amnesia in two olfactory learning tasks when administered into the prelimbic cortex (PLC). Thus, in experiment 1, DCS (10 µg/site) was infused prior to acquisition of odor discrimination (ODT) and social transmission of food preference (STFP), which have been previously characterized as paradigms sensitive to PLC muscarinic blockade. Immediately after learning such tasks, SCOP was injected (20 µg/site) and the effects of both drugs (alone and combined) were tested in 24-h retention tests. To assess whether DCS effects may depend on the difficulty of the task, in the STFP the rats expressed their food preference either in a standard two-choice test (experiment 1) or a more challenging three-choice test (experiment 2). The results showed that bilateral intra-PLC infusions of SCOP markedly disrupted the ODT and STFP memory tests. Additionally, infusions of DCS alone into the PLC enhanced ODT but not STFP retention. However, the DCS treatment reversed SCOP-induced memory deficits in both tasks, and this effect seemed more apparent in ODT and 3-choice STFP. Such results support the interaction between the glutamatergic and the cholinergic systems in the PLC in such a way that positive modulation of the NMDA receptor/channel, through activation of the glycine binding site, may compensate dysfunction of muscarinic neurotransmission involved in stimulus-reward and relational learning tasks.

Protective effect of Cnestis ferruginea and its active constituent on scopolamine-induced memory impairment in mice: a behavioral and biochemical study

CONTEXT

Cnestis ferruginea Vahl ex DC (Connaraceae) (CF) is used in traditional African medicine in the management of CNS disorders. The degeneration and dysfunction of cholinergic neurons is closely associated with the cognitive deficits of Alzheimer's disease (AD) and oxidative stress has been implicated in its pathogenesis. However, the influence of C. ferruginea on the cholinergic system and oxidative stress parameters has not been explored.

OBJECTIVE

The present study investigates the effect of methanol root extract of C. ferruginea and its active constituent amentoflavone (CF-2) on memory, oxidative stress and acetylcholinesterase (AChE) activity in scopolamine-induced amnesia.

MATERIALS AND METHODS

Mice were orally treated with CF (25-200 mg/kg), CF-2 (6.25-25 mg/kg) for three days and memory impairment was induced by intraperitoneal injection of scopolamine (3 mg/kg). Memory function was evaluated by passive avoidance and Morris water maze tests. Biochemical parameters of oxidative stress and cholinergic function were estimated in brain after the completion of behavioral studies.

RESULTS

Scopolamine caused memory impairment along with increased AChE activity and oxidative stress in mice brain. Oral administration of CF and CF-2 significantly prevented scopolamine-induced memory impairment, inhibited AChE and enhanced antioxidant enzyme activity in the brain following scopolamine injection as compared to vehicle administration in scopolamine (i.p.)-treated mice that were comparable to the effect of tacrine.

DISCUSSION AND CONCLUSION

The study demonstrated that C. ferruginea and its constituent have significant protective effect against scopolamine-induced memory deficits in mice that can be attributed to their antioxidant and antiAChE activity.