Biosynthesis of medicinal tropane alkaloids in yeast.

Tropane alkaloids from nightshade plants are neurotransmitter inhibitors that are used for treating neuromuscular disorders and are classified as essential medicines by the World Health Organization1,2. Challenges in global supplies have resulted in frequent shortages of these drugs3,4. Further vulnerabilities in supply chains have been revealed by events such as the Australian wildfires5 and the COVID-19 pandemic6. Rapidly deployable production strategies that are robust to environmental and socioeconomic upheaval7,8 are needed. Here we engineered baker's yeast to produce the medicinal alkaloids hyoscyamine and scopolamine, starting from simple sugars and amino acids. We combined functional genomics to identify a missing pathway enzyme, protein engineering to enable the functional expression of an acyltransferase via trafficking to the vacuole, heterologous transporters to facilitate intracellular routing, and strain optimization to improve titres. Our integrated system positions more than twenty proteins adapted from yeast, bacteria, plants and animals across six sub-cellular locations to recapitulate the spatial organization of tropane alkaloid biosynthesis in plants. Microbial biosynthesis platforms can facilitate the discovery of tropane alkaloid derivatives as new therapeutic agents for neurological disease and, once scaled, enable robust and agile supply of these essential medicines.

Cholinergic and behavior-dependent beta and gamma waves are coupled between olfactory bulb and hippocampus.

Olfactory oscillations may enhance cognitive processing through coupling with beta (ß, 15-30 Hz) and gamma (γ, 30-160 Hz) activity in the hippocampus (HPC). We hypothesize that coupling between olfactory bulb (OB) and HPC oscillations is increased by cholinergic activation in control rats and is reduced in kainic-acid-treated epileptic rats, a model of temporal lobe epilepsy. OB γ2 (63-100 Hz) power was higher during walking and immobility-awake (IMM) compared to sleep, while γ1 (30-57 Hz) power was higher during grooming than other behavioral states. Muscarinic cholinergic agonist pilocarpine (25 mg/kg ip) with peripheral muscarinic blockade increased OB power and OB-HPC coherence at ß and γ1 frequency bands. A similar effect was found after physostigmine (0.5 mg/kg ip) but not scopolamine (10 mg/kg ip). Pilocarpine increased bicoherence and cross-frequency coherence (CFC) between OB slow waves (SW, 1-5 Hz) and hippocampal ß, γ1 and γ2 waves, with stronger coherence at CA1 alveus and CA3c than CA1 stratum radiatum. Bicoherence further revealed a nonlinear interaction of ß waves in OB with ß waves at the CA1-alveus. Beta and γ1 waves in OB or HPC were segregated at one phase of the OB-SW, opposite to the phase of γ2 and γ3 (100-160 Hz) waves, suggesting independent temporal processing of ß/γ1 versus γ2/γ3 waves. At CA1 radiatum, kainic-acid-treated epileptic rats compared to control rats showed decreased theta power, theta-ß and theta-γ2 CFC during baseline walking, decreased CFC of HPC SW with γ2 and γ3 waves during baseline IMM, and decreased coupling of OB SW with ß and γ2 waves at CA1 alveus after pilocarpine. It is concluded that ß and γ waves in the OB and HPC are modulated by a slow respiratory rhythm, in a cholinergic and behavior-dependent manner, and OB-HPC functional connectivity at ß and γ frequencies may enhance cognitive functions.

The effect of intravenous hyoscine butylbromide on slow progress in labor (BUSCLAB): A double-blind randomized placebo-controlled trial.

BACKGROUND: Prolonged labor is a common condition associated with maternal and perinatal complications. The standard treatment with oxytocin for augmentation of labor increases the risk of adverse outcomes. Hyoscine butylbromide is a spasmolytic drug with few side effects shown to shorten labor when used in a general population of laboring women. However, research on its effect on preventing prolonged labor is lacking. We aimed to assess the effect of hyoscine butylbromide on the duration of labor in nulliparous women showing early signs of slow labor. METHODS AND FINDINGS: In this double-blind randomized placebo-controlled trial, we included 249 nulliparous women at term with 1 fetus in cephalic presentation and spontaneous start of labor, showing early signs of prolonged labor by crossing the alert line of the World Health Organization (WHO) partograph. The trial was conducted at Oslo University Hospital in Norway from May 2019 to December 2021. One hundred and twenty-five participants were randomized to receive 1 ml hyoscine butylbromide (Buscopan) (20 mg/ml), while 124 received 1 ml sodium chloride intravenously. Randomization was computer-generated, with allocation concealment by opaque sequentially numbered sealed envelopes. The primary outcome was duration of labor from administration of the investigational medicinal product (IMP) to vaginal delivery, which was analyzed by Weibull regression to estimate the cause-specific hazard ratio (HR) of vaginal delivery between the 2 treatment groups, with associated 95% confidence interval (CI). A wide range of secondary maternal and perinatal outcomes were also evaluated. Time-to-event outcomes were analyzed by Weibull regression, whereas continuous and dichotomous outcomes were analyzed by median regression and logistic regression, respectively. All main analyses were based on the modified intention-to-treat (ITT) set of eligible women with signed informed consent receiving either of the 2 treatments. The follow-up period lasted during the postpartum hospital stay. All personnel, participants, and researchers were blinded to the treatment allocation. Median (mean) labor duration from IMP administration to vaginal delivery was 401 (440.8) min in the hyoscine butylbromide group versus 432.5 (453.6) min in the placebo group. We found no statistically significant association between IMP and duration of labor from IMP administration to vaginal delivery: cause-specific HR of 1.00 (95% CI [0.77, 1.29]; p = 0.993). Among 255 randomized women having received 1 dose of IMP, 169 women (66.3%) reported a mild adverse event: 75.2% in the hyoscine butylbromide group and 57.1% in the placebo group (Pearson's chi-square test: p = 0.002). More than half of eligible women were not included in the study because they did not wish to participate or were not included upon admission. The participants might have represented a selected group of women reducing the external validity of the study. CONCLUSIONS: One intravenous dose of 20 mg hyoscine butylbromide was not found to be superior to placebo in preventing slow labor progress in a population of first-time mothers at risk of prolonged labor. Further research is warranted to answer whether increased and/or repeated doses of hyoscine butylbromide might have an effect on duration of labor. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03961165) EudraCT (2018-002338-19).

Cognitive-Enhancing Effects of Acetylcholine Receptor Agonists in Group-Housed Cynomolgus Monkeys Who Drink Ethanol.

The cognitive impairments that are often observed in patients with alcohol use disorder (AUD) partially contribute to the extremely low rates of treatment initiation and adherence. Brain acetylcholine receptors (AChR) mediate and modulate cognitive and reward-related behavior, and their distribution can be altered by long-term heavy drinking. Therefore, AChRs are promising pharmacotherapeutic targets for treating the cognitive symptoms of AUD. In the present study, the procognitive efficacy of two AChR agonists, xanomeline and varenicline, were evaluated in group-housed monkeys who self-administered ethanol for more than 1 year. The muscarinic AChR antagonist scopolamine was used to disrupt performance of a serial stimulus discrimination and reversal (SDR) task designed to probe cognitive flexibility, defined as the ability to modify a previously learned behavior in response to a change in reinforcement contingencies. The ability of xanomeline and varenicline to remediate the disruptive effects of scopolamine was compared between socially dominant and subordinate monkeys, with lighter and heavier drinking histories, respectively. We hypothesized that subordinate monkeys would be more sensitive to all three drugs. Scopolamine dose-dependently impaired performance on the serial SDR task in all monkeys at doses lower than those that produced nonspecific impairments (e.g., sedation); its potency did not differ between dominant and subordinate monkeys. However, both AChR agonists were effective in remediating the scopolamine-induced deficit in subordinate monkeys but not in dominant monkeys. These findings suggest xanomeline and varenicline may be effective for enhancing cognitive flexibility in individuals with a history of heavy drinking. SIGNIFICANCE STATEMENT: Procognitive effects of two acetylcholine (ACh) receptor agonists were assessed in group-housed monkeys who had several years' experience drinking ethanol. The muscarinic ACh receptor agonist xanomeline and the nicotinic ACh receptor agonist varenicline reversed a cognitive deficit induced by the muscarinic ACh receptor antagonist scopolamine. However, this effect was observed only in lower-ranking (subordinate) monkeys and not higher-ranking (dominant monkeys). Results suggest that ACh agonists may effectively remediate alcohol-induced cognitive deficits in a subpopulation of those with alcohol use disorder.

Database-aided ultrahigh-performance liquid chromatography Q-Exactive-Orbitrap tandem mass spectrometry putatively identifies 16 unexpected compounds and three anticounterfeiting pharmacopoeia quality markers for Perillae Fructus.

RATIONALE: Perillae Fructus (PF) is a common traditional Chinese medicine (TCM) for the treatment of asthma. It has not been effectively characterized by rosmarinic acid (RosA), which is currently designed as the sole quality indicator in the Chinese Pharmacopoeia. METHODS: This study introduced a database-aided ultrahigh-performance liquid chromatography equipped with quadrupole-Exactive-Orbitrap mass spectrometry (UHPLC/Q-Exactive-Orbitrap MS/MS) technology to putatively identify the compounds in PF, followed by literature research, quantum chemical calculation, and molecular docking to screen potential quality markers (Q-markers) of PF. RESULTS: A total of 27 compounds were putatively identified, 16 of which had not been previously found from PF. In particular, matrine, scopolamine, and RosA showed relatively high levels of content, stability, and drug-likeness. They exhibited interactions with the asthma-related target and demonstrated the TCM properties of PF. CONCLUSIONS: The database-aided UHPLC/Q-Exactive-Orbitrap MS/MS can identify at least 27 compounds in PF. Of these, 16 compounds are unexpected, and three compounds (matrine, scopolamine, and RosA) should be considered anticounterfeiting pharmacopoeia Q-markers of PF.

Effect of curcumin-donepezil combination on spatial memory, astrocyte activation, and cholinesterase expressions in brain of scopolamine-treated rats.

BACKGROUND: The study investigated the effect of co-administration of curcumin and donepezil on several markers of cognitive function (such as spatial memory, astrocyte activation, cholinesterase expressions) in the brain cortex and hippocampus of scopolamine-treated rats. METHOD AND RESULTS: For seven consecutive days, a pre-treatment of curcumin (50 mg/kg) and/or donepezil (2.5 mg/kg) was administered. On the seventh day, scopolamine (1 mg/kg) was administered to elicit cognitive impairment, 30 min before memory test was conducted. This was followed by evaluating changes in spatial memory, cholinesterase, and adenosine deaminase (ADA) activities, as well as nitric oxide (NO) level were determined. Additionally, RT-qPCR for glial fibrillary acidic protein (GFAP) and cholinesterase gene expressions was performed in the brain cortex and hippocampus. Also, GFAP immunohistochemistry  of the brain tissues for neuronal injury were performed in the brain cortex and hippocampus. In comparison to the control group, rats given scopolamine had impaired memory, higher levels of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and ADA activities, as well as elevated markers of oxidative stress. In addition to enhanced GFAP immunoreactivity, there was also overexpression of the GFAP and BChE genes in the brain tissues. The combination of curcumin and donepezil was, however, observed to better ameliorate these impairments in comparison to the donepezil-administered rat group. CONCLUSION: Hence, this evidence provides more mechanisms to support the hypothesis that the concurrent administration of curcumin and donepezil mitigates markers of cognitive dysfunction in scopolamine-treated rat model.

Mitigating cognitive deficits with teriflunomide: unraveling PI3K-modulated behavioral outcomes in mice.

BACKGROUND: Alzheimer's disease is a leading neurological disorder that gradually impairs memory and cognitive abilities, ultimately leading to the inability to perform even basic daily tasks. Teriflunomide is known to preserve neuronal activity and protect mitochondria in the brain slices exposed to oxidative stress. The current research was undertaken to investigate the teriflunomide's cognitive rescuing abilities against scopolamine-induced comorbid cognitive impairment and its influence on phosphatidylinositol-3-kinase (PI3K) inhibition-mediated behavior alteration in mice. METHODS: Swiss albino mice were divided into 7 groups; vehicle control, scopolamine, donepezil + scopolamine, teriflunomide (10 mg/kg) + scopolamine; teriflunomide (20 mg/kg) + scopolamine, LY294002 and LY294002 + teriflunomide (20 mg/kg). Mice underwent a nine-day protocol, receiving scopolamine injections (2 mg/kg) for the final three days to induce cognitive impairment. Donepezil, teriflunomide, and LY294002 treatments were given continuously for 9 days. MWM, Y-maze, OFT and rota-rod tests were conducted on days 7 and 9. On the last day, blood samples were collected for serum TNF-α analysis, after which the mice were sacrificed, and brain samples were harvested for oxidative stress analysis. RESULTS: Scopolamine administration for three consecutive days increased the time required to reach the platform in the MWM test, whereas, reduced the percentage of spontaneous alternations in the Y-maze, number of square crossing in OFT and retention time in the rota-rod test. In biochemical analysis, scopolamine downregulated the brain GSH level, whereas it upregulated the brain TBARS and serum TNF-α levels. Teriflunomide treatment effectively mitigated all the behavioral and biochemical alterations induced by scopolamine. Furthermore, LY294002 administration reduced the memory function and GSH level, whereas, uplifted the serum TNF-α levels. Teriflunomide abrogated the memory-impairing, GSH-lowering, and TNF-α-increasing effects of LY294002. CONCLUSION: Our results delineate that the improvement in memory, locomotion, and motor coordination might be attributed to the oxidative and inflammatory stress inhibitory potential of teriflunomide. Moreover, PI3K inhibition-induced memory impairment might be attributed to reduced GSH levels and increased TNF-α levels.

α-bisabolol ß-d-fucopyranoside (ABFP) ameliorates scopolamine-induced memory deficits through cholinesterase inhibition and attenuation of oxidative stress in zebrafish (Danio rerio).

Alzheimer's disease (AD) is one of the major devastating neurodegenerative disorders associated with the gradual decline of an individual's memory, cognition, and ability to carry out day-to-day activities. In the present study, the neuroprotective ability of α-bisabolol ß-d-fucopyranoside (ABFP) was assessed via measurement of antioxidant parameters like lipid peroxidation, glutathione peroxidation, glutathione, protein carbonyl content assays, and caspase-3 activity estimation. Moreover, the acute toxicity of ABFP was estimated in the zebrafish larval model. The results showed that ABFP exhibits little to no toxicity at lower concentrations in the acute toxicity test. ABFP-pretreated and scopolamine-exposed fish exhibited more exploratory behavior in the behavior assay than scopolamine-only induced groups. Additionally, the results of antioxidant enzyme assays revealed reduced oxidative stress and damage in ABFP-treated fish, while enzyme activity experiments carried out with brain homogenate from ABFP-treated fish showed decreased acetylcholinesterase enzyme activity. Overall, it can be concluded that ABFP has the potential to be a promising agent for the treatment of AD in the future.

Shark fish oil prevents scopolamine-induced memory impairment in an experimental model.

Fish oil has been known for its antioxidant, cardioprotective, anti-inflammatory, and neuroprotective characteristics due to the presence of polyunsaturated fatty acids (PUFAs) that are essential for optimal brain function and mental health. The present study investigated the effect of Carcharhinus Bleekeri (Shark Fish) oil on learning and memory functions in scopolamine-induced amnesia in rats. Locomotor and memory-enhancing activity in scopolamine-induced amnesic rats was investigated by assessing the open field and passive avoidance paradigm. Forty male Albino mice were divided into 4 equal groups (n = 10) as bellow: 1 - control (received 0.9% saline), 2 - SCOP (received scopolamine 2 mg/kg for 21 days), 3 - SCOP + SFO (received scopolamine and fish oil 5 mg/kg/ day for 21 days), 4 - SCOP + Donepezil groups (received 3 mg/kg/day for 21 days). SFO produced significant (P < 0.01) locomotor and memory-enhancing activities in open-field and passive avoidance paradigm models. Additionally, SFO restored the Acetylcholine (ACh) concentration in the hippocampus (p < 0.05) and remarkably prevented the degradation of monoamines. Histology of brain tissue showed marked cellular distortion in the scopolamine-treated group, while the SFO treatment restored distortion in the brain's hippocampus region. These results suggest that the SFO significantly ameliorates scopolamine-induced spatial memory impairment by attenuating the ACh and monoamine concentrations in the rat's hippocampus.

Ferulago Angulata methanolic extract ameliorates scopolamine-induced memory impairment through the inhibition of hippocampal monoamine oxidase activity.

Ferulago angulata is a medicinal herb from the Apiaceae family known for its antioxidant, anti-apoptotic, and neuroprotective properties. This study aimed to assess the effects of F. angulata extract on neurobehavioral and biochemical parameters in scopolamine-induced amnesic rats. Fifty-six male Wistar rats were divided into seven groups and orally treated with F. angulata extract (100, 200, 400 mg/kg) and Rivastigmine (1.5 mg/kg) for 10 days. Starting on the sixth day of treatment, the Morris water maze behavioral study was conducted to evaluate cognitive function, with scopolamine administered 30 min before training. Biochemical assays, including monoamine oxidase and oxidative stress measures, were performed on hippocampal tissue. Results showed that extract treatment significantly attenuated scopolamine-induced memory impairment in a dose-dependent manner. Following scopolamine administration, malondialdehyde levels and monoamine oxidase A/B activity increased, while total thiol content and catalase activity decreased compared to the control group. Pretreatment with F. angulata extracts ameliorated the scopolamine-induced impairment in all factors. Toxicological evaluation of liver, lung, heart, and kidney tissues did not indicate any side effects at high doses. The total extract of F. angulata prevents scopolamine-induced learning and memory impairment through antioxidant mechanisms and inhibition of monoamine oxidase. These results suggest that F. angulata extract is effective in the scopolamine model and could be a promising agent for preventing dementia, especially Alzheimer's disease.

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 10 mg/kg), group III (Cur EUD Nc 10 mg/kg), group IV (free Cur 10 mg/kg), and group V (SCO). Treatments with Nc or Cur (free) were performed daily or on alternate days. After 30 min of treatment, the animals received the SCO and were subjected to behavioral tests 30 min 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.

The Effect of Hyoscine N-Butyl Bromide Rectal on the Duration of Labour and Rate of Cervical Dilatation: A Systematic Review and Meta-Analysis.

OBJECTIVE: The current meta-analysis was designed to investigate the impact of Hyoscine N-butyl bromide (HBB) rectal on labour duration and the rate of cervical dilatation by consolidating the available data. METHODS: The search of Medline through the PubMed interface, Scopus, ScienceDirect, and the Cochrane Central Register of Controlled Trials (CENTRAL) was performed for original articles concerning the effects of HBB rectal on the duration of labour published prior to 26 June 2023. Search terms were based on Medical Subject Headings without time and language restrictions. They included: Hyoscine, Scopolamine, HBB, Buscopan, Buscolysin, Buscapine, rectal, suppository, childbirth, delivery, active phase, second stage, cervical dilatation, labour, labour, and duration of labour. The Comprehensive Meta-Analysis V3 software was used for all analyses. RESULTS: Five randomized control trials and 1 non-randomized study involving 1310 women were included in the systematic review. Two studies were excluded from the meta-analysis because of heterogeneous interventions and a lack of mean and SD results. The results determined that HBB rectal administration significantly decreased the duration of the active phase (pooled mean difference -193.893; 95% CI -229.173 to -158.613, P < 0.001; I2 squares = 90.097%) and second stage of labour (pooled mean difference -2.911; 95% CI -5.486 to -0.336, P = 0.027; I2 squares = 90.097%). Also, the cervical dilatation rate in the active phase of labour was 0.981 cm/h higher than in the control group (I2 = 0.0%; P < 0.001). CONCLUSION: This meta-analysis found that HBB rectal administration shortened the active labour phase and second stage and increased the rate of cervix dilatation; consequently, it can be used as a cost-effective intervention for low-risk pregnant women during labour. However, our findings also suggest that more robust clinical trials are required to generate evidence and confirm the use of HBB during labour for clinical practice guidelines.

Nelumbo nucifera leaves extract ameliorated scopolamine-induced cognition impairment via enhanced adult hippocampus neurogenesis.

In this presentation, we explored the molecular mechanisms of N. nucifera leaf water extracts (NLWEs) and polyphenol extract (NLPE) on scopolamine-induced cell apoptosis and cognition defects. The administration of NLWE and NLPE did not alter the body weight and serum biomarker rs and significantly ameliorated scopolamine-induced cognition impairment according to Y-maze test analysis. In mice, treatment with scopolamine disrupted normal histoarchitecture in the hippocampus, whereas the administration of NLWE and NLPE reversed the phenomenon. Western blot analysis revealed that scopolamine mitigated the expression of doublecortin (DCX), nestin, and NeuN, and cotreatment with NLWE or NLPE significantly recovered the expression of these proteins. NLWE and NLPE upregulated DCX and NeuN expression in the hippocampus region, as evidenced by immunohistochemical staining analysis of scopolamine-treated mice. NLWE and NLPE obviously elevated brain-derived neurotrophic factor (BDNF) and enhanced its downstream proteins activity. NLWE and NLPE attenuated scopolamine-induced apoptosis by reducing Bax and increased Bcl-2 expression. In addition, scopolamine also triggered apoptosis in human neuroblastoma SH-SY5Y cells whereas co-treatment with NLWE or quercetin-3-glucuronide (Q3G) reversed the phenomenon. NLWE or Q3G enhanced Bcl-2 and reduced Bax expression in the presence of scopolamine in SH-SY5Y cells. NLWE or Q3G recovered the inhibitory effects of scopolamine on neurogenesis and BDNF signals in SH-SY5Y cells. Overall, our results revealed that N. nucifera leaf extracts and Q3G promoted adult hippocampus neurogenesis and prevented apoptosis to mitigate scopolamine-induced cognition dysfunction through the regulation of BDNF signaling pathway.

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.

Extracts of Sideritis scardica and Clinopodium vulgare Alleviate Cognitive Impairments in Scopolamine-Induced Rat Dementia.

Sideritis scardica Griseb. and Clinopodium vulgare L., belonging to the Lamiaceae family, are rich in terpenoids and phenolics and exhibit various pharmacological effects, including antioxidant, anti-inflammatory and anti-cancer activities. While the memory-enhancing impacts of S. scardica are well documented, the cognitive benefits of C. vulgare remain unexplored. This study assessed the potential effect of C. vulgare on learning and memory in healthy and scopolamine (Sco)-induced memory-impaired male Wistar rats, comparing it with the effects of S. scardica. Over a 21-day period, rats orally received extracts of cultivated S. scardica (200 mg/kg) and C. vulgare (100 mg/kg), either individually or in combination, with administration starting 10 days before and continuing 11 days simultaneously with Sco injection at a dose of 2 mg/kg intraperitoneally. The results showed that both extracts effectively mitigated Sco-induced memory impairment. Their combination significantly improved recognition memory and maintained monoaminergic function. S. scardica excelled in preserving spatial working memory, while C. vulgare exhibited comparable retention of recognition memory, robust antioxidant activity and acetylcholinesterase inhibitory activity. The extracts alleviated Sco-induced downregulation of p-CREB/BDNF signaling, suggesting neuroprotective mechanisms. The extract combination positively affected most of the Sco-induced impairments, underscoring the potential for further investigation of these extracts for therapeutic development.

The Impact of LY487379 or CDPPB on eNOS Expression in the Mouse Brain and the Effect of Joint Administration of Compounds with NO• Releasers on MK-801- or Scopolamine-Driven Cognitive Dysfunction in Mice.

The role of endothelial nitric oxide synthase (eNOS) in the regulation of a variety of biological processes is well established, and its dysfunction contributes to brain pathologies, including schizophrenia or Alzheimer's disease (AD). Positive allosteric modulators (PAMs) of metabotropic glutamate (mGlu) receptors were shown to be effective procognitive compounds, but little is known about their impact on eNOS expression and stability. Here, we investigated the influence of the acute and chronic administration of LY487379 or CDPPB (mGlu2 and mGlu5 PAMs), on eNOS expression in the mouse brain and the effect of the joint administration of the ligands with nitric oxide (NO) releasers, spermineNONOate or DETANONOate, in different combinations of doses, on MK-801- or scopolamine-induced amnesia in the novel object recognition (NOR) test. Our results indicate that both compounds provoked eNOS monomer formation, and CDPPB at a dose of 5 mg/kg exaggerated the effect of MK-801 or scopolamine. The coadministration of spermineNONOate or DETANONOate enhanced the antiamnesic effect of CDPPB or LY487379. The best activity was observed for ineffective or moderate dose combinations. The results indicate that treatment with mGluR2 and mGluR5 PAMs may be burdened with the risk of promoting eNOS uncoupling through the induction of dimer dissociation. Administration of the lowest possible doses of the compounds with NO• donors, which themselves have procognitive efficacy, may be proposed for the treatment of schizophrenia or AD.

The protective effect of Astaxanthin on scopolamine - induced Alzheimer's model in mice.

OBJECTIVES: To investigate the fundamental mechanisms of the neuroprotective impact of Astaxanthin (AST) in a mouse model of Alzheimer's disease (AD) induced by scopolamine. METHODS: This research constituted an in vivo animal study encompassing 36 adult male mice, divided into 6 groups: Control, 100 mg/kg AST, 2 mg/kg scopolamine (AD group), 100 mg/kg AST+2 mg/kg scopolamine, 3 mg/kg galantamine+2 mg/kg scopolamine, and 100 mg/kg AST+3 mg/kg galantamine+2 mg/kg scopolamine. After 14 days, the mice's short-term memory, hippocampus tissue, oxidative and inflammatory markers were evaluated. RESULTS: The AST demonstrated a beneficial influence on short-term memory and a reduction in acetylcholinesterase activity in the brain. It exhibited neuroprotective and anti-amyloidogenic properties, significantly decreased pro-inflammatory markers and oxidative stress, and reversed the decline of the Akt-1 and phosphorylated Akt pathway, a crucial regulator of abnormal tau. Furthermore, AST enhanced the effect of galantamine in reducing inflammation and oxidative stress. CONCLUSION: The findings indicate that AST may offer therapeutic benefits against cognitive dysfunction in AD. This is attributed to its ability to reduce oxidative stress, control neuroinflammation, and enhance Akt-1 and pAkt levels, thereby underscoring its potential in AD treatment strategies.

Activating M1 muscarinic cholinergic receptors induces destabilization of resistant contextual fear memories in rats.

Destabilization of previously consolidated memories places them in a labile state in which they are open to modification. However, strongly encoded fear memories tend to be destabilization-resistant and the conditions required to destabilize such memories remain poorly understood. Our lab has previously shown that exposure to salient novel contextual cues during memory reactivation can destabilize strongly encoded object location memories and that activity at muscarinic cholinergic receptors is critical for this effect. In the current study, we similarly targeted destabilization-resistant fear memories, hypothesizing that exposure to salient novelty at the time of reactivation would induce destabilization of strongly encoded fear memories in a muscarinic receptor-dependent manner. First, we show that contextual fear memories induced by 3 context-shock pairings readily destabilize upon memory reactivation, and that this destabilization is blocked by systemic (ip) administration of the muscarinic receptor antagonist scopolamine (0.3 mg/kg) in male rats. Following that, we confirm that this effect is dorsal hippocampus (dHPC)-dependent by targeting M1 receptors in the CA1 region with pirenzepine. Next, we show that more strongly encoded fear memories (induced with 5 context-shock pairings) resist destabilization. Consistent with our previous work, however, we report that salient novelty (a change in floor texture) presented during the reactivation session promotes destabilization of resistant contextual fear memories in a muscarinic receptor-dependent manner. Finally, the effect of salient novelty on memory destabilization was mimicked by stimulating muscarinic receptors with the selective M1 agonist CDD-0102A (ip, 0.3 mg/kg). These findings reveal further generalizability of our previous results implicating novel cues and M1 muscarinic signaling in promoting destabilization of resistant memories and suggest possible therapeutic options for disorders characterized by persistent, maladaptive fear memories such as PTSD and phobias.

Muscarinic and NMDA Receptors in the Substantia Nigra Play a Role in Reward-Related Learning.

BACKGROUND: Reward-related learning, where animals form associations between rewards and stimuli (i.e., conditioned stimuli [CS]) that predict or accompany those rewards, is an essential adaptive function for survival. METHODS: In this study, we investigated the mechanisms underlying the acquisition and performance of conditioned approach learning with a focus on the role of muscarinic acetylcholine (mACh) and NMDA glutamate receptors in the substantia nigra (SN), a brain region implicated in reward and motor processes. RESULTS: Using RNAscope in situ hybridization assays, we found that dopamine neurons of the SN express muscarinic (mACh5), NMDA2a, NMDA2b, and NMDA2d receptor mRNA but not mACh4. NMDA, but not mACh5, receptor mRNA was also found on SN GABA neurons. In a conditioned approach paradigm, rats were exposed to 3 or 7 conditioning sessions during which light/tone (CS) presentations were paired with delivery of food pellets, followed by a test session with CS-only presentations. Intra-SN microinjections of scopolamine (a mACh receptor antagonist) or AP-5 (a NMDA receptor antagonist) were made either prior to each conditioning session (to test their effects on acquisition) or prior to the CS-only test (to test their effects on expression of the learned response). Scopolamine and AP-5 produced dose-dependent significant reductions in the acquisition, but not performance, of conditioned approach. CONCLUSIONS: These results suggest that SN mACh and NMDA receptors are key players in the acquisition, but not the expression, of reward-related learning. Importantly, these findings redefine the role of the SN, which has traditionally been known for its involvement in motor processes, and suggest that the SN possesses attributes consistent with a function as a hub of integration of primary reward and CS signals.

Involvement of aberrant acinar cell proliferation in scopolamine-induced dry eye mice.

Dry eye is a multifactorial disease that causes dryness, inflammation and damage of ocular surface. Subcutaneous injection of the muscarinic cholinergic antagonist scopolamine under desiccating stress reduces tear production and induces dry eye symptoms in mice. However, the expression profile and pathogenic changes of the lacrimal gland remain incompletely understood. In the present study, we performed comparative transcriptomic analysis of lacrimal glands from the control and scopolamine-treated mice. Primary analysis identified 677 upregulated genes and 269 downregulated genes in the lacrimal gland of mice with scopolamine treatment. Unexpectedly, KEGG pathway and hierarchical clustering analysis showed the enrichment of "DNA replication" and "cell cycle" categories in the upregulated genes. Subsequently, we confirmed that the acinar cells were the major proliferating cells of lacrimal gland, which exhibited significant increasing of the proliferating cell nuclear antigen (PCNA) expression after scopolamine treatment, accompanied with the upregulation of DNA damage marker γ-H2AX. More importantly, both prophylactic and therapeutic administration of the cyclin-dependent kinase (CDK) inhibitor AT7519 rescued the tear reduction and alleviated dry eye severity in the scopolamine-treated mice, including corneal epithelial barrier function, lacrimal and corneal inflammation, and conjunctival goblet cell density. Therefore, we conclude that aberrant acinar cell proliferation is involved in the scopolamine-induced tear reduction and dry eye onset, which can be improved by AT7519 treatment.