Amnesia Model Research Articles

Neuroprotective Potential of Origanum majorana L. Essential Oil Against Scopolamine-Induced Memory Deficits and Oxidative Stress in a Zebrafish Model

Origanum majorana L., also known as sweet marjoram, is a plant with multiple uses, both in the culinary field and traditional medicine, because of its major antioxidant, anti-inflammatory, antimicrobial, and digestive properties. In this research, we focused on the effects of O. majorana essential oil (OmEO, at concentrations of 25, 150, and 300 μL/L), evaluating chemical structure as well as its impact on cognitive performance and oxidative stress, in both naive zebrafish (Danio rerio), as well as in a scopolamine-induced amnesic model (SCOP, 100 μM). The fish behavior was analyzed in a novel tank-diving test (NTT), a Y-maze test, and a novel object recognition (NOR) test. We also investigated acetylcholinesterase (AChE) activity and the brain’s oxidative stress status. In parallel, we performed in silico predictions (research conducted using computational models) of the pharmacokinetic properties of the main compounds identified in OmEO, using platforms such as SwissADME, pKCSM, ADMETlab 2.0, and ProTox-II. The results revealed that the major compounds were trans-sabinene hydrate (36.11%), terpinen-4-ol (17.97%), linalyl acetate (9.18%), caryophyllene oxide (8.25%), and α-terpineol (6.17%). OmEO can enhance memory through AChE inhibition, reduce SCOP-induced anxiety by increasing the time spent in the top zone in the NTT, and significantly reduce oxidative stress markers. These findings underscore the potential of using O. majorana to improve memory impairment and reduce oxidative stress associated with cognitive disorders, including Alzheimer’s disease (AD).

Blackcurrant (Ribes nigrum L.) and Its Association with Donepezil Restore Cognitive Impairment, Suppress Oxidative Stress and Pro-inflammatory Responses, and Improve Purinergic Signaling in a Scopolamine-Induced Amnesia Model in Mice.

Purinergic signaling plays a major role in aging and neurodegenerative diseases, which are associated with memory decline. Blackcurrant (BC), an anthocyanin-rich berry, is renowned for its antioxidant and neuroprotective activities. However, evidence on the effects of BC on purinergic signaling is lacking. This study investigated the effects of BC and its association with Donepezil (DNPZ) on learning and memory, on the modulation of purinergic signaling, pro-inflammatory responses, and oxidative markers in a mouse model of cognitive impairment chronically induced by scopolamine (SCO). Animals were divided into twelve groups and treated with BC (50 or 100mg/kg), and/or DNPZ (5mg/kg), and/or SCO (1mg/kg). Results showed that SCO decreased spatial learning and memory as assessed by the Morris Water Maze test, and treatment with BC and/or DNPZ restored these effects. Furthermore, BC and/or DNPZ treatments also prevented changes in ecto-nucleoside triphosphate diphosphohydrolase (NTPDase) and adenosine deaminase (ADA) activities and restored the increased density of P2X7 and A2A receptors in synaptosomes of the cerebral cortex of SCO-induced mice. Moreover, the increased Nod-like receptor protein 3 (NLRP3) and interleukin-1β expression, and the oxidative stress markers levels were reduced by BC and/or DNPZ treatments, compared with the SCO group. Overall, BC and/or DNPZ treatments ameliorated SCO-induced cognitive decline, alleviated oxidative stress and pro-inflammatory responses, and improved purinergic signaling. These findings underscore the potential of BC, especially when in combination with DNPZ, as a therapeutic agent for the prevention of memory deficits associated with aging or neurological diseases.

Quality Controls: The Role of Self-Corrective Science in Explorations of Primate Memory Systems.

In 1978, Mort Mishkin published a landmark paper describing a monkey model of H.M.'s dense, global amnesia. It depended on a combined removal of the amygdala and hippocampus (the A + H lesion) and a memory test called delayed nonmatching-to-sample (DNMS). My first project examined whether the impairment Mishkin had found in visual memory generalized to tactual stimuli. However, to gain access to the hippocampus and amygdala with 1980s surgical methods, we had to remove the underlying cortex. When we were able to test the effects of bilateral removal of that underlying cortex (the entorhinal and perirhinal cortex, or "rhinal cortex" for short) we obtained a dramatic result. This so-called "control" lesion caused a profound impairment on the DNMS task. A few years later, excitotoxic A + H lesions, which left the rhinal cortex intact, confirmed that removal of the cortical "impediments" had caused the entire memory impairment that Mishkin had observed. These results: (1) forced a reconsideration of the monkey model of global anterograde amnesia; (2) spurred study of the independent contributions of the amygdala, hippocampus, and perirhinal cortex to cognition; and (3) led to the realization that the DNMS task did not test the kinds of memory that H.M. lost after his surgery.

Phytochemical characterization and evaluation of anti-amnesic activity of two source plants of Shankhapushpi

BackgroundShankhapushpi is an important Ayurvedic drug used for treating various disease conditions of nervous system. Convolvulus prostratus Forssk. is the genuine source plant for Shankhapushpi as per Ayurvedic Pharmacopoeia of India; however Clitorea ternatea L. is widely used as Shankhapushpi in southern part of India. In this study, comparative phytochemical and pharmacological evaluation has been done in two plants such as Convolvulus prostratus and Clitorea ternatea used as Shankhapushpi. MethodsPhytochemical comparison was done by High Performance Thin Layer Chromatography (HPTLC) and High Performance Liquid Chromatography (HPLC). Detailed metabolite profiling was performed using Q-TOF-LC/MS-MS analysis. Antiamnesic activity of selected plants has been evaluated against scopolamine induced amnesia model in Wistar rats. ResultsPhytochemical studies showed that only a few chemical constituents are common for both species. Most of the phytochemicals are different for selected species. LC/MS analysis showed presence of genipin and 7-hydroxyflavone in both species. Pharmacological study showed that both plants possess antiamnesic activity against Scopolamine induced memory loss; However C. ternatea possesses significant antiamnesic activity than that of C. prostratus. ConclusionThe study provided valuable information about the selected species in terms of its phytochemical composition and pharmacological properties. The study also provided a scientific support for using both species as Shankhapushpi.

The Biochemical Effects of Hydroalcoholic Extract of Quercus brantii Fruit on Morphine-Induced Amnesia in the Presence and Absence of Cholinergic Muscarinic Receptors in Adult Male Mice

Background: In our previous study, we demonstrated that oak hydroalcoholic extract improves memory impairment in a postpartum depression model due to its antioxidant properties. The purpose of this study is to further investigate the effect of oak on another amnesia model and explore the mediating role of cholinergic muscarinic receptors. Objectives: This study investigated the effect of hydroalcoholic extract of oak fruit on amnesia induced by morphine in the presence and absence of cholinergic muscarinic receptors, as well as changes in serum biochemical factors. Methods: In this experimental study, adult male mice were divided into groups: Control and morphine-receiving (5 and 7.5 mg/kg) groups to induce amnesia after training. In the groups receiving 7.5 mg/kg morphine, oak extract (1 and 10 mg/kg) was administered one day after training and continued for one week. Atropine (0.1 and 1 mg/kg) was injected only on the first day after training and before the oak extract injection. Passive avoidance memory was evaluated 1, 3, and 7 days after training using a step-down device. Motor activity was assessed using the open field test. Blood biochemical factors, including triglycerides, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total antioxidant capacity (TAC), were measured after one week of injections. Results: Morphine (7.5 mg/kg) impaired memory on days 1 and 7 (P < 0.05), while oak extract (1 and 10 mg/kg) improved memory (P < 0.001). Additionally, the oak extract maintained its enhancing effect even in the presence of atropine, a cholinergic muscarinic system antagonist. Oak extract significantly increased HDL and TAC levels but did not affect LDL, cholesterol, and triglyceride levels. Conclusions: These findings suggest that oak extract can improve morphine-induced amnesia due to its antioxidant effect, without involving the cholinergic system. Additionally, oak extract can increase beneficial lipids without affecting harmful lipids.

Blackcurrant (Ribes nigrum L.) improves cholinergic signaling and protects against chronic Scopolamine-induced memory impairment in mice.

Blackcurrant (Ribes nigrum L.) is a berry rich in anthocyanins, bioactive compounds known for their antioxidant and neuroprotective properties that benefit human health. This study aimed to investigate the effects of blackcurrant and its association with Donepezil on memory impairment, cholinergic neurotransmission, and antioxidant systems in a mouse model of amnesia induced by chronic administration of Scopolamine. Adult male Swiss mice were given saline, blackcurrant (50 mg/kg, orally), and/or Donepezil (5 mg/kg, orally) and/or Scopolamine (1 mg/kg, intraperitoneally). Behavioral tests revealed that blackcurrant and/or Donepezil prevented the learning and memory deficits induced by Scopolamine. In the cerebral cortex and hippocampus, blackcurrant and/or Donepezil treatments prevented the increase in acetylcholinesterase and butyrylcholinesterase activities induced by Scopolamine. Scopolamine also disrupted the glutathione redox system and increased levels of reactive species; nevertheless, blackcurrant and/or Donepezil treatments were able to prevent oxidative stress. Furthermore, these treatments prevented the increase in gene expression and protein density of acetylcholinesterase and the decrease in gene expression of the choline acetyltransferase enzyme induced by Scopolamine. Findings suggest that blackcurrant and Donepezil, either alone or in combination, have anti-amnesic effects by modulating cholinergic system enzymes and improving the redox profile. Therefore, blackcurrant could be used as a natural supplement for the prevention and treatment of memory impairment in neurodegenerative diseases.

Ethanolic extract of Actinidia chinensis var. delicious fruit ameliorates scopolamine-induced cognitive impairment in rats

AimThe present study was to assess the anti-amnesic effect of Actinidia chinensis var deliciosa in a rat model of scopolamine-induced amnesia. Method36 rats were divided into 6 groups and assigned name to each group i.e. Group 1 rats (normal control) received 1 ml/kg normal saline for 14 days intraperitoneally (i.p.). Group 2 rats received scopolamine (3 mg/kg, i.p.) 30 min prior to the trial on the 14th day. Group 3 rats received 3 mg/kg/day of donepezil as pre-treatment for 14 days and scopolamine (3 mg/kg, i.p.) 30 min before the trial on the 14th day. Group 4, 5, and 6 rats received Actinidia chinensis var deliciosa (200, 400, and 600 mg/kg/day) for 14 days and scopolamine (3 mg/kg, i.p) 30 min before the trial on the 14th day respectively. On day 15, 6 rats from each group were sacrificed and the brain tissue of these rats was isolated for the estimation of biochemical parameters, and histopathological examination. ResultScopolamine-treated rats demonstrated increased escape latency and lipid peroxidation levels in the hippocampus compared to the control group (p < 0.001). However, pre-treatment with Actinidia chinensis var deliciosa extract (ACEE) at various doses and the standard drug donepezil significantly improved these parameters. Histopathological examination revealed that ACEE and donepezil protected against pyramidal cell degeneration, neuronophagia, and vascular inflammation in scopolamine-treated rats. Discussion: Actinidia chinensis var deliciosa showed promising anti-amnesic activity against scopolamine-induced amnesia in rats. This could be attributed to its brain acetylcholinesterase level and alteration in neurotransmitter level.

A comprehensive assessment of the cholinergic-supporting and cognitive-enhancing effects of Rosa damascena Mill. (Damask rose) essential oil on scopolamine-induced amnestic rats.

Alzheimer's disease (AD) is a neurodegenerative condition characterized by gradual loss of cognitive abilities (dementia) and is a major public health problem. Here, we aimed at investigating the effects of Rosa damascena essential oil (RDEO) on learning and memory functions in a rat model of amnesia induced by scopolamine, as well as on changes in acetylcholinesterase (AChE) activity, M1 muscarinic acetylcholine receptor (mAChR) expression, and brain-derived neurotrophic factor (BDNF) levels in the extracted brain tissues. The control, amnesia (scopolamine, 1mg/kg/i.p.) and treatment (RDEO, 100μL/kg/p.o. or galantamine, 1.5mg/kg/i.p.) groups were subjected to Morris water maze and new object recognition tests. AChE activity was assayed by ELISA, and M1 mAChR and BDNF concentration changes were determined by western blotting. Also, using computational tools, human M1 mAChR was modeled in an active conformation, and the major components of RDEO were docked onto this receptor. According to our behavioral tests, RDEO was able to mitigate the learning and memory impairments caused by scopolamine in vivo. Our in vitro assays showed that the observed positive effects correlated well with a decrease in AChE activity and an increase in M1 mAChR and BDNF levels in amnestic rat brains. We also demonstrated in an in silico setting that the major components of RDEO, specifically -citronellol, geraniol, and nerol, could be accommodated favorably within the allosteric binding pocket of active-state human M1 mAChR and anchored here chiefly by hydrogen-bonding and alkyl-π interactions. Our findings offer a solid experimental foundation for future RDEO-based medicinal product development for patients suffering from AD.

Exploring the neuropharmacological potential of empagliflozin on nootropic and scopolamine-induced amnesic model of Alzheimer’s like conditions in rats

Background Alzheimer’s disease (AD) is one of the most challenging and prevalent neurodegenerative disorder globally with a rising prevalence, characterized by progressive cognitive decline, memory loss, and behavioural changes. Current research aims to determine the nootropic and anti-amnesic effect of Empagliflozin (EMPA) against scopolamine-induced amnesia in rats, by modulating the cholinergic and N-Methyl D-Aspartate (NMDA) receptors. Methods Rats were treated once daily with an EMPA (5 and 10 mg/kg) and donepezil (2.5 mg/kg) for successive 26 days. During the final 13 days of treatment, a daily injection of scopolamine (1 mg/kg) was administered to induce cognitive deficits. Results EMPA was found to be significantly reduce escape latency, increase time spent in the target quadrant, and enhanced the number of target zone crossings in the Morris water maze (MWM) test, indicating improved spatial memory. Moreover, EMPA increased the recognition index and the number of spontaneous alternations in the novel object recognition (NOR) and Y-maze tests, respectively, suggesting enhanced memory. Discussion Interestingly doses of EMPA (5 mg/kg, 10 mg/kg) exhibited memory-enhancing effects even in the absence of scopolamine-induced impairment. Biochemical analysis revealed that EMPA elevated the levels of glutathione (GSH), a potent antioxidant, while decreasing lipid peroxidation (LPO) activity and increasing catalase (CAT) levels, indicating its antioxidative properties. Interestingly molecular docking studies revealed that EMPA fit perfectly in the active sites of M1 muscarinic acetylcholine (mACh) and NMDA receptors. These results indicated that the nootropic and antiamnesic effect of EMPA is possibly mediated via M1 and NMDA receptors and might be a remedy for AD.

Dihydroergotamine Increases Histamine Brain Levels and Improves Memory in a Scopolamine-Induced Amnesia Model.

The beneficial effects of increasing histamine levels on memory have acquired special interest due to their applicability to psychiatric conditions that cause memory impairments. In addition, by employing drug repurposing approaches, it was demonstrated that dihydroergotamine (DHE), an FDA drug approved to treat migraines, inhibits Histamine N Methyl Transferase (HNMT), the enzyme responsible for the inactivation of histamine in the brain. For this reason, in the present work, the effect of DHE on histamine levels in the hippocampus and its effects on memory was evaluated, employing the scopolamine-induced amnesia model, the Novel Object Recognition (NOR) paradigm, and the Morris Water Maze (MWM). Furthermore, the role of histamine 1 receptor (H1R) and histamine 2 receptor (H2R) antagonists in the improvement in memory produced by DHE in the scopolamine-induced amnesia model was evaluated. Results showed that the rats that received DHE (10 mg/kg, i.p.) showed increased histamine levels in the hippocampus after 1 h of administration but not after 5 h. In behavioral assays, it was shown that DHE (1 mg/kg, i.p.) administered 20 min before the training reversed the memory impairment produced by the administration of scopolamine (2 mg/kg, i.p.) immediately after the training in the NOR paradigm and MWM. Additionally, the effects in memory produced by DHE were blocked by pre-treatment with pyrilamine (20 mg/kg, i.p.) administered 30 min before the training in the NOR paradigm and MWM. These findings allow us to demonstrate that DHE improves memory in a scopolamine-induced amnesia model through increasing histamine levels at the hippocampus due to its activity as an HNMT inhibitor.

New curcumin-loaded nanocapsules as a therapeutic alternative in an amnesia model.

This study aimed to investigate the action of two different formulations of curcumin (Cur)-loaded nanocapsules (Nc) (Eudragit [EUD] and poly (ɛ-caprolactone) [PCL]) in an amnesia mice model. We also investigated the formulations' effects on scopolamine-induced (SCO) depressive- and anxiety-like comorbidities, the cholinergic system, oxidative parameters, and inflammatory markers. Male Swiss mice were randomly divided into five groups (n = 8): group I (control), group II (Cur PCL Nc 10mg/kg), group III (Cur EUD Nc 10mg/kg), group IV (free Cur 10mg/kg), and group V (SCO). Treatments with Nc or Cur (free) were performed daily or on alternate days. After 30min of treatment, the animals received the SCO and were subjected to behavioral tests 30min later (Barnes maze, open-field, object recognition, elevated plus maze, tail suspension tests, and step-down inhibitory avoidance tasks). The animals were then euthanized and tissue was removed for biochemical assays. Our results demonstrated that Cur treatment (Nc or free) protected against SCO-induced amnesia and depressive-like behavior. The ex vivo assays revealed lower acetylcholinesterase (AChE) and catalase (CAT) activity, reduced thiobarbituric species (TBARS), reactive species (RS), and non-protein thiols (NSPH) levels, and reduced interleukin-6 (IL-6) and tumor necrosis factor (TNF) expression. The treatments did not change hepatic markers in the plasma of mice. After treatments on alternate days, Cur Nc had a more significant effect than the free Cur protocol, implying that Cur may have prolonged action in Nc. This finding supports the concept that it is possible to achieve beneficial effects in nanoformulations, and treatment on alternate days differs from the free Cur protocol regarding anti-amnesic effects in mice.

Development of multi-targetable chalcone derivatives bearing N-aryl piperazine moiety for the treatment of Alzheimer's disease

The multi-target directed ligand (MTDL) discovery has been gaining immense attention in the development of therapeutics for Alzheimer’s disease (AD). The strategy has been evolved as an auspicious approach suitable to combat the heterogeneity and the multifactorial nature of AD. Therefore, multi-targetable chalcone derivatives bearing N-aryl piperazine moiety were designed, synthesized, and evaluated for the treatment of AD. All the synthesized compounds were screened for thein vitro activityagainst acetylcholinesterase (AChE), butylcholinesterase (BuChE), β-secretase-1 (BACE-1), and inhibition of amyloid β (Aβ) aggregation. Amongst all the tested derivatives, compound 41bearing unsubstituted benzylpiperazine fragment and para-bromo substitution at the chalcone scaffold exhibited balanced inhibitory profile against the selected targets. Compound 41 elicited favourable permeation across the blood–brain barrier in the PAMPA assay. The molecular docking and dynamics simulation studies revealed the binding mode analysis and protein–ligand stability ofthe compound with AChE and BACE-1. Furthermore,itameliorated cognitive dysfunctions and signified memory improvement in thein-vivobehavioural studies (scopolamine-induced amnesia model). Theex vivobiochemical analysis of mice brain homogenates established the reduced AChE and increased ACh levels. The antioxidant activity of compound 41 was accessed with the determination of catalase (CAT) and malondialdehyde (MDA) levels. The findings suggested thatcompound 41, containing a privileged chalcone scaffold, can act as a lead molecule for developing AD therapeutics.

Retrograde amnesia for the stress-induced impairment of extinction: time-dependent and not so forgotten.

We investigated whether retrograde amnesia for the stress-induced impairment of extinction retrieval shares similar characteristics with original acquisition memories. The first experiment demonstrated that cycloheximide administered shortly after a single restraint stress session alleviated the impairment of extinction retrieval but not when administered following a longer delay (i.e., the amnesia for stress is time-dependent). A second experiment showed that the retrograde amnesia for stress could be alleviated by a second brief exposure to the stressor. These results demonstrating that amnesia for stress shares characteristics similar to original memories are explained using a retrieval-based memory integration model of retrograde amnesia.

Allosteric inhibition of phosphodiesterase 4D induces biphasic memory-enhancing effects associated with learning-activated signaling pathways.

Phosphodiesterase 4D negative allosteric modulators (PDE4D NAMs) enhance memory and cognitive function in animal models without emetic-like side effects. However, the relationship between increased cyclic adenosine monophosphate (cAMP) signaling and the effects of PDE4D NAM remains elusive. To investigate the roles of hippocampal cAMP metabolism and synaptic activation in the effects of D159687, a PDE4D NAM, under baseline and learning-stimulated conditions. At 3mg/kg, D159687 enhanced memory formation and consolidation in contextual fear conditioning; however, neither lower (0.3mg/kg) nor higher (30mg/kg) doses induced memory-enhancing effects. A biphasic (bell-shaped) dose-response effect was also observed in a scopolamine-induced model of amnesia in the Y-maze, whereas D159687 dose-dependently caused an emetic-like effect in the xylazine/ketamine anesthesia test. At 3mg/kg, D159687 increased cAMP levels in the hippocampal CA1 region after conditioning in the fear conditioning test, but not in the home-cage or conditioning cage (i.e., context only). By contrast, 30mg/kg of D159687 increased hippocampal cAMP levels under all conditions. Although both 3 and 30mg/kg of D159687 upregulated learning-induced Fos expression in the hippocampal CA1 30min after conditioning, 3mg/kg, but not 30mg/kg, of D159687 induced phosphorylation of synaptic plasticity-related proteins such as cAMP-responsive element-binding protein, synaptosomal-associated protein 25kDa, and the N-methyl-D-aspartate receptor subunit NR2A. Our findings suggest that learning-stimulated conditions can alter the effects of a PDE4D NAM on hippocampal cAMP levels and imply that a PDE4D NAM exerts biphasic memory-enhancing effects associated with synaptic plasticity-related signaling activation.

Design, Molecular Docking, Synthesis and Evaluation of Xanthoxylin Hybrids as Dual Inhibitors of IL‐6 and Acetylcholinesterase for Alzheimer’s Disease

AbstractBackgroundIL‐6 and AChE play a pivotal role in progression of AD, it is hypothesised that simultaneous inhibition of IL‐6 and AChE may prove as an effective strategy for treatment of AD. Therefore, the present study is undertaken to design novel molecules capable of acting as dual inhibitors of IL‐6 and AChE. Literature review reveals that xanthoxylin and a disubstituted amines or a carbamoyl amines are pharmacophores for IL‐6 and AChE inhibition, respectively.MethodXanthoxylin is coupled with various disubstituted amines or carbamoyl amines through alkyl linkers of different lengths (1‐4 carbon atoms) to design two series of 80 compounds. All designed compounds were docked into AChE to identify the best fit compounds for synthesis and evaluation of AChE inhibitory activity. The compounds showing &gt;45% inhibition of EeAChE are selected for evaluation of IL‐6 and butyrylcholinesterase (BuChE) inhibitory activities. The compound found to be most potent against AChE, BuChE and IL‐6 inhibition was finally evaluated in vivo using STZ‐induced amnesia model in mice at three doses (0.2, 0.4 and 0.8 mg/kg).ResultCompound K13g is found to be the most potent inhibitor of EeAChE, BuChE and IL‐6. It is further evaluated in vivo, wherein it shows dose‐dependent effects. It is observed to be less active at lower doses, but completely reversed the STZ‐induced memory deficit at 0.8 mg/kg.ConclusionThe findings suggest that a compound having a xanthoxylin moiety connected to a piperazine ring through a three‐carbon atom chain may provide a useful template for the development of new chemical entities effective against AD.

Immune activation state modulates infant engram expression across development.

Infantile amnesia is possibly the most ubiquitous form of memory loss in mammals. We investigated how memories are stored in the brain throughout development by integrating engram labeling technology with mouse models of infantile amnesia. Here, we found a phenomenon in which male offspring in maternal immune activation models of autism spectrum disorder do not experience infantile amnesia. Maternal immune activation altered engram ensemble size and dendritic spine plasticity. We rescued the same apparently forgotten infantile memories in neurotypical mice by optogenetically reactivating dentate gyrus engram cells labeled during complex experiences in infancy. Furthermore, we permanently reinstated lost infantile memories by artificially updating the memory engram, demonstrating that infantile amnesia is a reversible process. Our findings suggest not only that infantile amnesia is due to a reversible retrieval deficit in engram expression but also that immune activation during development modulates innate, and reversible, forgetting switches that determine whether infantile amnesia will occur.

Neuropeptide cyclo-L-prolylglycine counteracts scopolamine-induced long-term memory impairment in rats in the novel object recognition test

Background. Cyclo-L-prolylglycine (CPG) was designed and synthesized at the V.V. Zakusov as a topological analogue of the classical nootrop piracetam and was further identified as an endogenous compound. Previously, the nootropic effect of CPG was revealed in a model of retrograde amnesia in rats induced by electroconvulsive shock in the passive avoidance test (PAT).Objective. The aim of the present study was to investigate the nootropic effect of CPG under more physiological conditions in the absence of strong stressors.Methods. Amnesia in rats was modeled by intraperitoneal (ip) administration of scopolamine at a dose of 2 mg/kg. CPG was administered ip at doses of 0.1 and 1.0 mg/kg 15 minutes after scopolamine. Short- and long-term memory were recorded in the novel object recognition test.Results. It was found that scopolamine disrupted only the long-term memory of rats. CPG at a dose of 0.1 mg/ kg almost completely counteracted this impairment. CPG by itself had no effect on memory at both doses studied.Conclusion. Thus, CPG exhibits nootropic activity not only in the aversive conditions of the PAT and electroconvulsive shock-induced amnesia, but also in the neutral situation in the novel object recognition test, when the amnesia was caused by the administration of scopolamine.

Discovery of novel multifunctional ligands targeting GABA transporters, butyrylcholinesterase, β-secretase, and amyloid β aggregation as potential treatment of Alzheimer's disease

Alzheimer's disease (AD) is a global health problem in the medical sector that will increase over time. The limited treatment of AD leads to the search for a new clinical candidate. Considering the multifactorial nature of AD, a strategy targeting number of regulatory proteins involved in the development of the disease is an effective approach. Here, we present a discovery of new multi-target-directed ligands (MTDLs), purposely designed as GABA transporter (GAT) inhibitors, that successfully provide the inhibitory activity against butyrylcholinesterase (BuChE), β-secretase (BACE1), amyloid β aggregation and calcium channel blockade activity. The selected GAT inhibitors, 19c and 22a – N-benzylamide derivatives of 4-aminobutyric acid, displayed the most prominent multifunctional profile. Compound 19c (mGAT1 IC50 = 10 μM, mGAT4 IC50 = 12 μM and BuChE IC50 = 559 nM) possessed the highest hBACE1 and Aβ40 aggregation inhibitory activity (IC50 = 1.57 μM and 99 % at 10 μM, respectively). Additionally, it showed a decrease in both the elongation and nucleation constants of the amyloid aggregation process. In contrast compound 22a represented the highest activity and a mixed-type of eqBuChE inhibition (IC50 = 173 nM) with hBACE1 (IC50 = 9.42 μM), Aβ aggregation (79 % at 10 μM) and mGATs (mGAT1 IC50 = 30 μM, mGAT4 IC50 = 25 μM) inhibitory activity. Performed molecular docking studies described the mode of interactions with GATs and enzymatic targets. In ADMET in vitro studies both compounds showed acceptable metabolic stability and low neurotoxicity. Successfully, compounds 19c and 22a at the dose of 30 mg/kg possessed statistically significant antiamnesic properties in a mouse model of amnesia caused by scopolamine and assessed in the novel object recognition (NOR) task or the passive avoidance (PA) task.

Cajanus cajan (L) Millsp. seed extract ameliorates scopolamine-induced amnesia through increase in antioxidant defense mechanisms and cholinergic neurotransmission.

Decline in cholinergic function and oxidative/nitrosative stress play a central role in Alzheimer's disease (AD). Previous quantitative HPLC profiling analysis has revealed the presence of Pinostrobin, formononetin, vitexin and other neuroprotective flavonoids in Cajanus cajan seed extract. This study was designed to investigate the protective action of Cajanus cajan ethanol seed extract (CC) on learning and memory functions using scopolamine mouse model of amnesia. Materials and methods: Adult mice were pretreated with CC (50, 100, or 200mg/kg, p.o) or vehicle (10ml/kg, p.o) for 16 days consecutively. Scopolamine, a competitive muscarinic cholinergic receptor antagonist (1mg/kg, i.p.) was given an hour after CC pretreatment from days 3 to 16. The mice were subjected to behavioural tests from day 11 (open field test (OFT)/ Y-maze test (YMT) and Morris water maze task (MWM) from days 12-16. Animals were euthanized 1h after behavioral test on day 16 and discrete brain regions isolated for markers of oxidative stress and cholinergic signaling. Molecular docking analysis was undertaken to predict the possible mechanism(s) of CC-induced anti-amnesic action. pre-administration of CC significantly reversed working memory and learning deficits caused by scopolamine in YMT and MWM tests, respectively. Moreover, CC prevented scopolamine-induced oxidative and nitrosative stress radicals in the hippocampus evidenced in significant increase in glutathione (GSH) level, superoxide dismutase (SOD) and catalase (CAT) activities with a marked decrease in malondialdehyde (MDA) production, as well as significant inhibition of hippocampal scopolamine-induced increase in acetylcholinesterase activity by CC. The molecular docking analysis showed that out of the 19 compounds, the following had the highest binding affinity; Pinostrobin (-8.7 Kcal/mol), friedeline (-7.5kCal/mol), and lupeol (-8.2 Kcal/mol), respectively, to neuronal muscarinic M1 acetylcholine receptor, α7 nicotinic acetylcholine receptor and amyloid beta peptide binding pockets, which further supports the ability of CC to enhance neuronal cholinergic signaling and possible inhibition of amyloid beta aggregation. This study showed that Cajanus cajan seeds extract improved working memory and learning through enhancement of cholinergic signaling, antioxidant capacity and reduction in amyloidogenesis.

Neurocognitive and neuroprotective potential of Mimusops elengi in mice model of scopolamine-induced amnesia

Neurocognitive and neuroprotective potential of Mimusops elengi in mice model of scopolamine-induced amnesia