Acetylcholinesterase--new roles for an old actor

Exposure to metoprolol and propranolol mixtures on biochemical, immunohistochemical, and molecular alterations in the American oyster, Crassostrea virginica

Pharmaceutical drugs, particularly beta-blockers (e.g., metoprolol, propranolol, etc.), are extensively used to treat human cardiovascular conditions, yet pose significant risks to non-target aquatic organisms when introduced into coastal and marine environments via wastewater effluent. This study aimed to investigate the effects of short-term exposure (one week) to environmentally relevant concentrations of metoprolol and propranolol (MP) mixtures (low-dose: 50 ng/L propranolol and 250 ng/L metoprolol, and high-dose: 250 ng/L propranolol and 650 ng/L metoprolol) in the American oyster (Crassostrea virginica, a commercially and ecologically important marine bivalve mollusk) under controlled laboratory conditions. Histopathological assessments revealed structural damage to gills, connective tissues, and digestive glands in both low- and high-dose MP treatment groups. Additionally, glucose concentration and pH of the extrapallial fluid significantly declined in the high-dose MP treatment groups. Hemocyte density in the connective tissues increased proportionally with MP dosages. MP mixtures significantly reduced mucous secretion in the gills and digestive glands. Immunohistochemical results showed significant (P < 0.05) upregulation of 3-nitrotyrosine protein (NTP, a biomarker of protein nitration) expression in tissues of oysters exposed to MP mixtures. Alongside, exposure to MP significantly (P < 0.05) decreased acetylcholinesterase (AChE, a cholinergic enzyme) expression in oyster tissues. Our findings suggest that beta-blockers induce protein nitration, leading to altered tissue morphology, disrupting extrapallial fluid homeostasis, and downregulating AChE expression that may impair physiological functions in oysters.

Exposure to malathion impairs learning and memory of zebrafish by disrupting cholinergic signal transmission, undermining synaptic plasticity, and aggravating neuronal apoptosis

The prevalence of organophosphorus pesticides, such as malathion, in water environments poses a severe threat to aquatic organisms. Although the brain is a potential target for malathion, little is known about its effect on cognitive functions in fish. In this study, we evaluated the effect of 4-week malathion exposure on the learning and memory of zebrafish using T-maze tasks. In addition to verifying the accumulation of malathion in the brain and its deleterious effects on blood-brain barrier integrity, the impacts of malathion on cholinergic signal transmission, synaptic plasticity, apoptosis, and oxidative stress were determined. Our results demonstrated that a 4-week malathion exposure resulted in typical learning and memory-deficit-like behaviors. Apart from inhibiting cholinergic signal transmission, synaptic plasticity was severely undermined by malathion (as evidenced by the disruption of BDNF/PI3K/AKT/CREB pathway, suppression of synaptophysins, and activation of microglia). Moreover, significantly higher levels of TUNEL fluorescence signals as well as apoptotic enzymes and genes probably induced by oxidative stress were detected in the brains of malathion-exposed zebrafish. Collectively, our results suggested that malathion at environmentally realistic levels can significantly undermine learning and memory of zebrafish by disrupting cholinergic signal transmission, impairing synaptic plasticity, and aggravating neuronal apoptosis via inducing oxidative stress.

2-Ethylhexanol induces autism-like neurobehavior and neurodevelopmental disorders in zebrafish

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by impaired social interaction, communication deficits, and repetitive behaviors. The rising prevalence of ASD necessitates intensified research. 2-Ethylhexanol, is a synthetically produced branched-chain alcohol used in plasticizer synthesis. However, its role in ASD-like symptoms and potential neurotoxic effects remains largely unexplored. This study employed a multimodal neurotoxicity testing approach to evaluate the adverse effects of 2-ethylhexanol on zebrafish neurobehavior and neurodevelopment. Wild-type and transgenic zebrafish lines (tg(elavl3: eGFP) and tg(mbp:mGFP)) were exposed to 2-ethylhexanol for 120 hours post-fertilization (hpf). Significant disruptions were observed in early motor activities, such as tail coiling and touch-evoked responses, which aligned with later locomotor impairments, including reduced distance traveled and increased turn angle. These behavioral changes were accompanied by decreased levels of acetylcholinesterase (AChE) and dopamine (DA). Deficits in social behavior (e.g., reduced body contact) were identified, potentially linked to altered transcription of autism-associated genes (adsl, eif4a1, mbd5, vps13b, and tsc1b). Abnormalities in neurogenesis, including reduced brain and spinal cord size, and demyelination of oligodendrocytes and Schwann cells, were evident. Additionally, transcriptional changes related to neurodevelopment (gap43, manf, sox2) and neurotransmitter signaling (drd1, mao, htr1bd) were observed. Our findings provide compelling evidence that 2-ethylhexanol exposure leads to neurodevelopmental impairments and behavioral alterations reminiscent of ASD. This research highlights the importance of further investigations to assess the potential risks of 2-ethylhexanol exposure and develop prevention and mitigation strategies.

Molecular insight on conformational alterations and functional changes of acetylcholinesterase induced by an emerging environmental pollutant 6PPD-quinone

The emerging pollutant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-quinone) has attracted broad attention because of its widespread presence and harmful impacts, including hepatotoxicity and neurotoxicity. Acetylcholinesterase (AChE) is commonly used as a classical biomarker for assessing toxicity in the nervous system. Here, the interaction mechanism between AChE and 6PPD-quinone was investigated using a combination of multispectral and computational approaches, including enzyme activity assay, fluorescence thermodynamic titration, circular dichroism (CD) spectroscopy, molecular dynamics (MD) simulation, computational alanine scanning (CAS), and free energy landscape (FEL) analysis, among others. The result indicates that 6PPD-quinone spontaneously binds into the active site of AChE, thereby competitively inhibiting enzyme's activity. The interaction is primarily facilitated by hydrogen bonds and van der Waals forces, exhibiting a binding constant (Kb) of 1.044 × 104 M-1 at 298 K. The introduction of 6PPD-quinone causes a reduction in the α-helix content of AChE, making the structure less stable and more relaxed. Furthermore, the FEL analysis of AChE revealed that, with the presence of 6PPD-quinone, the number of global minima of AChE increased from 2 to 2-3. Additionally, Molecular docking outcomes exhibit that 6PPD-quinone interacted with tyrosine (TYR) 337, TYR124, tryptophan (TRP) 86, serine (SER) 203, glycine (GLY) 120 and other residues of AChE. CAS analysis shows binding free energy changes (ΔΔGbinding) of TRP86, TYR337 were 5.17 and 2.57 kcal mol-1, respectively, highlighting their key roles in the binding process of 6PPD-quinone with AChE. The interactions of 6PPD-quinone with the TRP86 and TYR337 may be the reason for the decrease in AChE activity.

Elevated Cholinesterase Activity and the Metabolic Syndrome-Dissecting Fatty Liver, Insulin Resistance and Dysglycaemia

BACKGROUND AND AIMS

While low plasma butyrylcholinesterase (BChE) is a well-established marker of reduced liver synthesis capacity, the clinical significance of elevated BChE is unclear. In small studies, high BChE has long been suspected in hepatic steatosis and metabolic syndrome. We aimed to clarify the relation between BChE, liver fat and glucose metabolism in deeply phenotyped cohorts.

METHODS

Plasma BChE activity was measured in 844 humans (554 women) of the cross-sectional Tübingen Diabetes Family Study, with a wide BMI range (17.7-55.1 kg/m2). It was furthermore measured before and after two independent lifestyle intervention studies in 215 and 116 participants. Liver fat was quantified with 1H-MR-spectroscopy, and metabolism was assessed by oral glucose tolerance tests.

RESULTS

BChE was positively associated with liver fat, independent of sex, age and BMI. BChE was higher in participants with metabolic syndrome. BChE was positively associated with fasting and 2-h glycaemia, independent of sex, age and BMI. BChE was negatively associated with insulin sensitivity, independent of sex, age, BMI and liver fat. The reduction of liver fat and improvement in insulin sensitivity during lifestyle interventions are associated with the reduction in BChE, independent of body weight loss.

CONCLUSIONS

Higher plasma BChE activity is linked to liver fat accumulation, as well as impaired glucose tolerance and insulin resistance, independent of liver fat. This suggests that BChE could be a marker for processes in hepatocytes that contribute to impaired glucose metabolism. Further investigations are needed to clarify the mechanistic contribution and potential diagnostic value of elevated BChE in hepatic steatosis and metabolic diseases.

Tripeptides inhibit dual targets AChE and BACE-1: a computational study

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss, with amyloid-beta (Aβ) plaques and acetylcholine deficits being central pathological features. Inhibition of dual targets including acetylcholinesterase (AChE) and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) represents a promising strategy to address cholinergic deficits and amyloid pathology. In this study, we used computational approaches to evaluate 8000 tripeptides as potential dual inhibitors of AChE and BACE-1. Machine learning models revealed the four top-lead tripeptides including WHM, HMW, WMH, and HWM. Molecular docking simulations indicated that WHM possessed the most favorable interactions through hydrogen bonds, π-π stacking, and salt bridges with key catalytic residues in both enzymes. Molecular dynamics simulations confirmed the stability of the protein-ligand complexes, with WHM exhibiting the most consistent conformations and significant disruption of catalytic residue geometries. Free energy perturbation analysis further supported WHM's superior stability across both targets. ADMET predictions suggested moderate oral absorption and limited brain penetration, consistent with the typical behavior of peptide-based compounds. Overall, WHM demonstrated the strongest potential as a dual inhibitor of AChE and BACE-1, offering a promising lead for future therapeutic development in AD.

Choline alleviates cognitive impairment in sleep-deprived young mice via reducing neuroinflammation and altering phospholipidomic profile

Cognitive impairment resulting from insufficient sleep poses a significant public health concern, particularly in children. The effects and mechanisms of choline on cognitive impairment caused by sleep deprivation are unknown. Chronic sleep deprivation is induced in young mice in this study, followed by feeding diet containing 11.36 g/kg choline bitartrate. Choline supplementation significantly improves spatial learning ability. Functional MRI results reveal the hippocampus as a key region affected by sleep deprivation, where choline supplementation notably preserves hippocampal structural integrity and enhanced connectivity. Additionally, choline ameliorates hippocampal pathological injury, reduces blood-brain barrier permeability and serum brain injury biomarkers. Choline also reduces inflammation and oxidative stress biomarkers, and mitigates microglial activation in the hippocampus, which preserves synaptic plasticity. A key finding is the changes of hippocampal phospholipidomic profile along with cognitive function, and a total of 313 phospholipid molecules are identified. Choline increases the levels of total phospholipid and sub-classes (particularly PC), which are strongly correlated with reduced neuroinflammation and oxidative stress biomarkers, as well as improved cognitive outcomes. Furthermore, there are similar findings in some phospholipid molecules such as PC 36:1, PC O-33:0, PC p-38:3, PE 36:3, PE p-42:4 and PS 44:12. These findings highlight that choline alleviates cognitive impairment in sleep deprivation via reducing neuroinflammation and oxidative stress as well as altering phospholipidomic profile. This study suggests that choline could develop into functional food or medicine ingredient to prevent and treat cognitive impairment by sleep disturbances, particularly children and adolescents.

Cholinesterase and Inflammation: Exploring Its Role and Associations with Inflammatory Markers in Patients with Lower Extremity Artery Disease

Background: Inflammation is a major driver of atherosclerotic diseases including lower extremity artery disease (LEAD). Serum cholinesterase (ChE) has been shown to impact cardiovascular health and regulate inflammatory processes. Objectives: The aim of this study was to investigate the relationship between serum ChE levels and inflammatory markers in patients with hemodynamically relevant iliac artery stenosis, assessing its potential role in the inflammatory processes of lower extremity artery disease (LEAD). Methods: In the following retrospective data analysis, we investigated 150 patients with hemodynamically relevant iliac artery stenosis as documented by a delta peak systolic velocity (δPSV) ≥ 1.4 m/s and investigated the possible influence of ChE on established inflammatory markers, such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and hemoglobin-to-platelet ratio (HPR), along with other routine laboratory or vascular parameters. Results: ChE levels differed significantly between patients with stable claudication (Fontaine stage II) and critical ischemia (Fontaine stages III and IV): 7.76 mg/dL (6.55-8.7 mg/dL) vs. 6.77 mg/dL (5.85-7.48 mg/dL), p = 0.004. Using the spearman correlation coefficient, testing of NLR and ChE revealed a highly significant inverse correlation, with a coefficient of -0.303 (p < 0.001). Additionally, a weak inverse correlation was observed between PLR and ChE, with a coefficient of -0.162 (p = 0.049). Patients with an elevated body mass index (BMI) showed increased levels of serum ChE, with a spearman correlation coefficient of 0.298 (p < 0.001). Conclusions: The observed correlations in this study depict active inflammation in LEAD with an emphasis on patients with critical ischemia. Serum ChE could serve as a potential biomarker for inflammation in patients with LEAD, particularly in distinguishing between stable claudication and critical ischemia. Future research is needed to explore the role of ChE as a complementary biomarker, offering insights into the cholinergic regulation of inflammation in LEAD.

Inhibitory Potential of Boscalid and Abamectin Towards Acetylcholinesterase and Butyrylcholinesterase: Computational and In Vitro Studies

The growing demand for agricultural products has led to the misuse of pesticides, resulting in the use of higher concentrations of these substances. This has led to an increase in toxicity imposed on other beneficial organisms and to the bioaccumulation of toxic pesticide concentrations in the bodies of both pests and non-target organisms, as well as in their end users, including humans. In this study, the neurotoxic potential of the commonly used pesticides abamectin (an insecticide) and boscalid (a fungicide) was evaluated. Both in vitro and in silico studies showed that human butyrylcholinesterase is not a target for abamectins B1A and B1B. Boscalid showed a modest Glide score (-28.8 kJ/mol) and a considerably higher IC50 (308.8 µM) against human butyrylcholinesterase than the approved inhibitor (2-((1-(benzenesulfonyl)-1H-indol-4-yl)oxy)ethyl)(benzyl)amine (IC50 = 0.473 µM). However, due to its non-mutagenicity and low toxicity, structural analogues of boscalid might be considered as candidates for the symptomatic treatment of Alzheimer's disease. Molecular dynamics simulations over 100 ns confirmed the stability of boscalid within the active site of butyrylcholinesterase, where it maintained key interactions with catalytic residues such as Trp82 and His438. These findings highlight its potential as a starting point for structure-based drug design strategies aimed at optimizing cholinesterase inhibitors with improved pharmacokinetic properties. According to absorption, distribution, metabolism, elimination, and toxicity studies, boscalid is orally active, which cannot be attributed to abamectins B1A and B1B.

Novel 2-Alkoxy-3-Cyanopyridine Derivatives as Cholinesterase Inhibitors: Synthesis, Biological Evaluation, and In Silico Investigations

Alzheimer's disease remains a major challenge in neuroscience and medicine. Cholinesterase inhibitors provide symptomatic relief but do not alter disease progression. While significant progress has been made in understanding its biology, there is an urgent need for effective therapies. In this study, a series of 2-alkoxy-3-cyanopyridine derivatives (1-7) were prepared and evaluated as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Among the compounds, 3 and 4 were identified as good inhibitors of AChE and BuChE with relatively low IC50 values. 3 inhibited AChE with an IC50 of 53.95 ± 4.29 µM, while 4 had a greater potency for BuChE with an IC50 of 31.79 ± 0.38 µM. Kinetic studies revealed that 3 and 4 are competitive inhibitors with Ki values of 14.23 ± 0.42 and 19.80 ± 3.38 µM for AChE and BuChE, respectively. In silico investigations, including docking studies, DFT calculations, and ADME/drug-likeness properties, were carried out to understand the mode of interaction of 3 and 4 toward the AChE and BuChE enzymes, as well as to determine their molecular geometry, chemical reactivity, and pharmacokinetic properties. This study highlights the potential of 3-cyanopyridine derivatives in the treatment of AD and provides a solid foundation for further optimization and exploration of their therapeutic applications.

From wetlands to landfills: white stork (Ciconia ciconia L., 1758) as a reliable bioindicator of ecosystem health

White storks (Ciconia ciconia L., 1758) and their nestlings have emerged as valuable bioindicators of environmental pollution, particularly in ecosystems affected by human activities. This review explores the role of white storks in biomonitoring, focusing on the use of biomarkers and pollutant analysis to understand the physiological consequences of environmental stressors. Key biomarkers, such as oxidative stress markers, immune responses, and hormonal alterations provide insight into the effects of pollutants like heavy metals, pesticides, and other toxic compounds. The biomarkers are typically measured in matrices such as blood, feathers, eggs, and tissues, each offering unique advantages in assessing pollutant exposure. However, ethical concerns regarding wildlife monitoring and the potential harm caused by invasive sampling techniques call for non-invasive methods. Future research should explore novel non-invasive techniques and employ long-term monitoring programmes to understand the cumulative effects of pollution. Despite challenges such as biological variability and environmental factors, white storks remain reliable indicators of ecological change and pollutant burden, providing critical data that can guide pollution management policies, inform conservation strategies, and protect both wildlife and human health from current environmental threats.

Pesticide and hydrocarbon toxicity in fish: effects on Chelon labrosus (Risso, 1827) along the northeastern Sicilian coast (Italy) evaluated by enzymatic biomarkers

Pesticides intoxication affects aquatic organisms as well as a group of contaminants that are represented by crude oil, petroleum hydrocarbons (PHs), polycyclic aromatic hydrocarbons (PAHs) and their derivatives. Useful tools for ecotoxicological studies of marine ecosystems are based on biomarker application on bioindicator key fish species. The aim of the present study was to highlight the presence of pesticides and hydrocarbons in a coastal marine environment, the harbour of Capo d'Orlando town (northeastern Sicily, Italy), by using the ecotoxicological biomarker Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) enzymatic activities in the key fish species Chelon labrosus. A reference site was selected. Chemical analysis of water samples was also carried out to analyze and eventually confirm the presence of pesticides in the study area. Results showed significant inhibition in AChE (80%) and BChE (77%) activities in fish from the harbour of Capo d'Orlando compared to the reference site. The esterase inhibition is primarily due to the presence of organophosphorus insecticides and carbamates, that resulted in higher concentrations of contaminants in the water of the harbour of Capo d'Orlando compared to the reference quality standard decree (Ministerial Decree 260, 2010). This study highlighted the contamination by insecticides and most probably by hydrocarbons in fish from the harbour of Capo d'Orlando, which also represents a threat to the human population consuming affected fish.

Inhibitor Action of Unsaturated Fatty Acids on Equine Serum Butyrylcholinesterase

Butyrylcholinesterase (BChE; EC 3.1.1.8), a serine hydrolase found in various tissues, hydrolyses choline esters such as acetylcholine and succinylcholine, as well as other esters such as heroin and acetylsalicylic acid. It is considered to play a role in lipid metabolism as it belongs to the same enzyme group as lipases and its catalytic subunits are similar. In this study, the effects of unsaturated fatty acids, namely arachidonic (AA), linoleic (LA), alpha-linolenic (ALA) and oleic acid (OA), on equine serum BChE (EqBChE) were investigated. Enzyme activity was measured by the modified Ellman method. When the activity results were evaluated, the IC50 values were found 45.49, 8.465, 1556, and 56.57 μM; while the Ki values were 63.92, 11.46, 1800, and 15.24 μM for AA, ALA, LA, and OA, respectively. Analysis of the kinetic results showed that ALA was compatible with mixed inhibition and other fatty acids were compatible with non-competitive inhibition, a special type of mixed inhibition. Molecular docking predicted binding of the fatty acids to the active site, as well as to predicted allosteric sites. The results of this study provide another support to the hypothesis that cholinesterases are associated with lipid metabolism.

Peripheral transcutaneous electrical stimulation to improve cognition: a review of the main effects in healthy humans and in mildly cognitively impaired patient populations

Peripheral nerve stimulation (PNS) is an ancient technique, up to now mainly used for pain management. The least invasive approach for PNS is transcutaneous electrical stimulation (TENS), which is performed by delivering mild electric currents through the skin and, depending on the stimulation pattern, activates the somatosensory Aβ-, Aδ- and C-fibers. In addition to its use for pain relief, accumulating data indicates that TENS can have broad-spectrum cognitive effects through the activation of neuromodulatory brain pathways. This review aims to summarize the current evidence on the cognitive effects of TENS, from healthy participants and mildly cognitively affected patients. Most studies on this topic have investigated the effects of TENS on memory, while fewer studies have explored attention, executive functions, and verbal fluency. Overall, promising evidence suggests that TENS may exert positive effects on specific cognitive functions. Further research is needed to build consensus on the most effective stimulation protocols, for both neurorehabilitation and enhancement, and to better understand the neurobiological mechanisms underlying the cognitive effects of TENS.

Characterization of acetylcholinesterase and carboxylesterases in the mangrove oyster Crassostrea gasar as biomarkers of exposure to environmental pollutants

Brazil is one of the world's leading consumers of agricultural pesticides, highlighting the urgent need to identify responsive biomarkers as diagnostic and prognostic tools for monitoring aquatic pollution. Acetylcholinesterase (AChE) and carboxylesterases (CbE) are B-esterases enzymes expressed in several organisms. AChE plays an essential role in neural transmission at cholinergic synapses, while CbE are directly involved in the detoxification of organic pollutants, including organophosphorus pesticides. The activities of AChE and CbE in bivalves have not been extensively investigated, despite their suitability as sentinel organisms for environmental monitoring. In this study, we characterized the activities of AChE and CbE in the mangrove oyster Crassostrea gasar, collected from an estuarine system in southern Brazil. We compared enzymatic activities between the gills and the digestive gland, revealing that CbE activity was significantly higher in the digestive gland, while AChE activity did not differ between the two tissues. These results indicate that the digestive gland functions as the primary metabolic organ in C. gasar. Additionally, we observed notable differences in CbE activity depending on the substrate used: ρ-nitrophenyl acetate (ρNPA), ρ-nitrophenyl butyrate (ρNPB), α-naphtyl acetate (αNA), and α-naphtyl butyrate (αNB). Our findings suggest that more lipophilic substrates are metabolized more rapidly in both the digestive gland and gills. These results enhance our understanding of the biotransformation processes and neurotoxicity potential of pesticides in oysters. However, further in vitro validation is needed to confirm the utility of these biomarkers for monitoring environmental pollution in coastal waters.

Repurposing of erythropoietin as a neuroprotective agent against methotrexate-induced neurotoxicity in rats

BACKGROUND

Methotrexate (MTX) is a cytotoxic drug that can trigger neurotoxicity via enhancing oxidative stress, apoptosis, and inflammation. On the other hand, erythropoietin (EPO) functions as an antioxidant, anti-apoptotic, and anti-inflammatory agent, in addition to its hematopoietic effects.

AIM

The present study was developed to examine the neuroprotective impact of EPO against MTX-provoked neurotoxicity in rats.

METHODS

Chemo fog was elicited in Wistar rats via injection of one dosage of MTX (20 mg/kg, i.p) on the sixth day of the study. EPO was injected at 500 IU/kg/day, i.p for 10 successive days.

RESULTS

MTX triggered memory and learning impairment as evidenced by Morris water maze, passive avoidance, and Y-maze cognitive tests. In addition, MTX induced oxidative stress as evident from the decline in hippocampal Nrf2 and HO-1 levels. MTX brought about apoptosis, as demonstrated by the elevation in p53, caspase-3, and Bax levels, as well as the decrease in Bcl2 levels. MTX also decreased Beclin-1, an autophagy-related marker, and increased P62 expression. In addition, MTX downregulated Sirt-1/AKT/FoxO3a pathway and increased miRNA-34a gene expression. Moreover, MTX increased acetylcholinesterase activity and reduced neurogenesis. EPO administration remarkably counteracted MTX-induced molecular and behavioral disorders in rat hippocampi.

CONCLUSION

Our findings impart preclinical indication for repurposing of EPO as a promising neuroprotective agent through modulating miRNA-34a, autophagy, and the Sirt-1/FoxO3a signaling pathway.

The relationship between deltamethrin-induced behavioral changes and acetylcholinesterase activity in zebrafish embryos or larvae based on transcriptome

Background

Deltamethrin (DM) is a broad-spectrum insecticide that is widely used to control agricultural pests. Recently, DM has posed a potential threat to the health of infants and young children, and this is because of the environmental and food pollution that is caused by the extensive use of DM.

Methods

In this study, zebrafish (Danio rerio) embryos were used as experimental animals to quantify the behavioral changes of larvae induced by DM and explore the relationship between DM and acetylcholinesterase activity.

Results

The results showed that DM caused an increase in coiling movement, heart rate, and apoptosis in the brain in early zebrafish embryos or larvae. It also caused a decrease in the expression of acetylcholinesterase-associated genes and the activity of acetylcholinesterase, which also led to an increase in the acetylcholinesterase content. The transcriptome data also showed that low concentration DM induced acetylcholine-related gene signaling pathways. The above results suggest that low doses of DM may induce neurodegeneration because DM exposure inhibits acetylcholinesterase, leading to brain cell apoptosis and behavioral changes in the zebrafish embryos or larvae. Micro-injection of zebrafish embryos at the 2-4 cell stage knocked down or overexpressed the acetylcholinesterase gene showed that the behavior and enzyme activity of zebrafish had some effects.

Conclusion

This study explored the relationship between acetylcholinesterase and the change in zebrafish behavior caused by DM exposure to provide a basis for the treatment of DM poisoning in the aquaculture.

Nanomedicine: A New Frontier in Alzheimer's Disease Drug Targeting

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder affecting elderly individuals, characterized by progressive cognitive decline leading to dementia. This review examines the challenges posed by anatomical and biochemical barriers such as the blood-brain barrier (BBB), blood-cerebrospinal fluid barrier (BCSFB), and p-glycoproteins in delivering effective therapeutic agents to the central nervous system (CNS) for AD treatment. This article outlines the fundamental role of acetylcholinesterase inhibitors (AChEIs) and NMDA(N-Methyl-D-Aspartate) receptor antagonists in conventional AD therapy and highlights their limitations in terms of brain-specific delivery. It delves into the intricacies of BBB and pglycoprotein- mediated efflux mechanisms that impede drug transport to the CNS. The review further discusses cutting-edge nanomedicine-based strategies, detailing their composition and mechanisms that enable effective bypassing of BBB and enhancing drug accumulation in brain tissues. Conventional therapies, namely AChEIs and NMDA receptor antagonists, have shown limited efficacy and are hindered by suboptimal brain penetration. The advent of nanotechnology-driven therapeutic delivery systems offers promising strategies to enhance CNS targeting and bioavailability, thereby addressing the shortcomings of conventional treatments. Various nanomedicines, encompassing polymeric and metallic nanoparticles (MNPs), solid lipid nanoparticles (SLNs), liposomes, micelles, dendrimers, nanoemulsions, and carbon nanotubes, have been investigated for their potential in delivering anti-AD agents like AChEIs, polyphenols, curcumin, and resveratrol. These nanocarriers exhibit the ability to traverse the BBB and deliver therapeutic payloads to the brain, thereby holding immense potential for effective AD treatment and early diagnostic approaches. Notably, nanocarriers loaded with AChEIs have shown promising results in preclinical studies, exhibiting improved therapeutic efficacy and sustained release profiles. This review underscores the urgency of innovative drug delivery approaches to overcome barriers in AD therapy. Nanomedicine-based solutions offer a promising avenue for achieving effective CNS targeting, enabling enhanced bioavailability and sustained therapeutic effects. As ongoing research continues to elucidate the complexities of CNS drug delivery, these advancements hold great potential for revolutionizing AD treatment and diagnosis.

Modification in ICU design may influence circadian serum cholinesterase activities: a proof-of-concept pilot study

BACKGROUND

Deficits in cholinergic function are assumed to cause cognitive decline. Studies have demonstrated that changes in serum cholinesterase activities are associated with a higher incidence of delirium in critically ill patients. Additionally, basic research indicates that the cholinergic and circadian systems are interconnected, with each system influencing the functionality of the other. This data analysis of a proof-of-concept pilot study investigates whether modification in ICU design, including dynamic light therapy, may influence the circadian oscillation of serum cholinesterase activities.

METHODS

We enrolled adult critically ill patients who were on mechanical ventilation and had an anticipated ICU stay of at least 48 h. The patients were treated in either modified or standard ICU rooms. The modified rooms received extensive architectural modifications, including a new dynamic lighting system. Serum acetylcholinesterase and butyrylcholinesterase activities were measured every four hours for up to three 24-h assessment periods.

RESULTS

We included 64 patients in the data analysis (n = 34 patients in modified rooms, n = 30 in standard rooms). The median values of serum acetylcholinesterase and butyrylcholinesterase activities showed different patterns. Acetylcholinesterase activities differed significantly between the groups during the first assessment period (p = 0.04) and the second assessment period (p = 0.045). The intensity of light, as quantified by the effective circadian irradiance, significantly influenced the activities of acetylcholinesterase and butyrylcholinesterase throughout all assessment periods for patients in both groups (p < 0.001). The analysis showed significant interaction (p < 0.001), indicating that the differences in acetylcholinesterase and butyrylcholinesterase activities between the groups were inconsistent over time but apparent during specific periods of the day.

CONCLUSION

Implementing a comprehensive set of changes to the design of ICU rooms, including a dynamic lighting system, may influence the course of the activity patterns of acetylcholinesterase and butyrylcholinesterase in critically ill patients. Modifications to environmental factors could potentially offer neuroprotective benefits and facilitate the realignment of circadian rhythms within the cholinergic system. Clinical trial registration ClinicalTrials.gov: NCT02143661. Registered May 21, 2014.

Red-shifted GRAB acetylcholine sensors for multiplex imaging in vivo

The neurotransmitter acetylcholine (ACh) is essential in both the central and peripheral nervous systems. Recent studies highlight the significance of interactions between ACh and various neuromodulators in regulating complex behaviors. The ability to simultaneously image ACh and other neuromodulators can provide valuable information regarding the mechanisms underlying these behaviors. Here, we developed a series of red fluorescent G protein-coupled receptor activation-based (GRAB) ACh sensors, with a wide detection range and expanded spectral profile. The high-affinity sensor, rACh1h, reliably detects ACh release in various brain regions, including the nucleus accumbens, amygdala, hippocampus, and cortex. Moreover, rACh1h can be co-expressed with green fluorescent sensors in order to record ACh release together with other neurochemicals in various behavioral contexts using fiber photometry and two-photon imaging, with high spatiotemporal resolution. These new ACh sensors can therefore provide valuable new insights regarding the functional role of the cholinergic system under both physiological and pathological conditions.

Esterase-responsive nanoparticles (ERN): A targeted approach for drug/gene delivery exploits

Nanoparticles are being developed to enhance drug delivery to cancer tumors, leveraging advantages such as the enhanced permeability and retention (EPR) effect. However, traditional nanoparticles often face challenges with low specificity for cancer cells, leading to inefficient delivery and unwanted side effects. Esterase-responsive nanoparticles offer a maximum targeted approach to tumor cells because they release their therapeutic payload at the tumor site under the influence of esterase activity. This review explores the role of esterase-responsive nanoparticles in drug and gene delivery, examines esterase prodrug therapy, and discusses prostate-specific membrane antigen (PSMA) targets esterase-responsive nanoparticles in prostate cancer treatment. Additionally, we reviewed the current research progress and future potential of esterase-responsive nanoparticles in enhancing drug and gene delivery.

Haloperidol-Induced Catalepsy and Its Correlations with Acetylcholinesterase Activity in Different Brain Structures of Mice

BACKGROUND/OBJECTIVES

Antipsychotic medicines are used to treat several psychological disorders and some symptoms caused by dementia and schizophrenia. Haloperidol (Hal) is a typical antipsychotic usually used to treat psychosis; however, its use causes motor or extrapyramidal symptoms (EPS) such as catalepsy. Hal blocks the function of presynaptic D2 receptors on cholinergic interneurons, leading to the release of acetylcholine (ACh), which is hydrolyzed by the enzyme acetylcholinesterase (AChE).

METHODS

This study was designed to investigate the Hal-inhibitory effects on AChE activity in regions representative of the cholinergic system of mice and potential associations between cataleptic effects generated by Hal using therapeutic doses and their inhibitory effects on AChE.

RESULTS

The distribution of the AChE activity in the different regions of the brain followed the order striatum > hippocampus > (prefrontal cortex/hypothalamus/ cerebellum) > brainstem > septo-hippocampal system. In ex vivo assays, Hal inhibited AChE activity obtained from homogenate tissue of the striatum, hippocampus, and septo-hippocampal system in a concentration-dependent manner. The inhibitory concentration of 50% of enzyme activity (IC50) indicated that the septo-hippocampal system required a higher concentration of Hal (IC50 = 202.5 µmol·L-1) to inhibit AChE activity compared to the striatum (IC50 = 162.5 µmol·L-1) and hippocampus (IC50 = 145 µmol·L-1). In in vivo assays, male Swiss mice treated with concentrations of Hal higher than 0.1 mg·kg-1 induced cataleptic effects. Positive correlations with Spearman's correlation were observed only between the lack of cataleptic effect and the decreased AChE activity of the hippocampus in the mice treated with 0.01 mg·kg-1 of Hal but not in the striatum and septo-hippocampal system.

CONCLUSIONS

Our results suggest that Hal could increase cholinergic effects via AChE inhibition, in addition to its dopamine antagonist effect, as an alternative approach to the treatment of behavioral disturbances associated with dementia.

Fluopyram SDHI pesticide alters fish physiology and behaviour despite low in vitro effects on mitochondria

Pollution from pesticides is an increasing concern for human health and biodiversity conservation. However, there is lack of knowledge about some emerging molecules such as SDHI fungicides (succinate dehydrogenase inhibitors) that are widely used but potentially highly toxic for vertebrates. Boscalid, fluopyram, and bixafen are 3 frequent SDHI molecules commonly detected in surface waters, which may pose risks to aquatic species. This study aimed to (1) test the in vitro effects of SDHI on mitochondrial activities (inhibition of succinate dehydrogenase SDH, also named respiratory chain complex II) and (2) assess the in vivo effects of sublethal SDHI concentrations on fish physiology and behaviour over 96 hours of exposure, using Carassius auratus fish as a model species. Results show that bixafen and boscalid inhibited complex II activities in vitro as expected (bixafen > boscalid), while fluopyram had no in vitro effects. In contrast, in vivo studies showed that fluopyram strongly altered fish behaviour (enhanced activity, social and feeding behaviours), likely explained by reduced AChE enzymatic activity. In addition, fluopyram increased muscle lipid content, suggesting metabolic disruption. These findings raise serious concern about the toxic effects of SDHI pesticides, especially fluopyram, although its underpinning molecular mechanisms remain to be explored. We thus encourage further research on the long-term impacts of SDHI pesticides to improve existing regulation and prevent adverse effects on wildlife.

Chronic effects of irregular and fibril microplastics on Artemia franciscana in a benthic environment: Size and shape-dependent toxicity

Marine ecosystems are contaminated by plastic products, particularly microplastics (MPs), which settle on the seafloor and affect benthic organisms. This study explores the toxicity of irregular fibril-shaped MPs of various sizes and lengths on Artemia franciscana. We exposed juvenile A. franciscana to irregular-shaped MPs of three sizes, small (<20 μm), medium (40-70 μm), and large (>120 μm), and MP fibers of two length categories, short (200-300 μm) and long (3 mm), in a sand-layered benthic system. The concentrations of the MPs were maintained at 0.05-20 mg/L, and the study was conducted over a 28-d of chronic period. Among all the MPs considered in this study, the small and short MPs exerted the most severe effects (causing mortality, growth inhibition, gut damage, alterations in movement, and a decrease in positive phototaxis). Our study highlights the importance of considering the morphological characteristics of MPs for analyzing their toxicity to aquatic eco-receptors.

Evaluation of chemical constituents in Norantea guianensis aubl. Extracts, embryotoxicity, and acetylcholinesterase inhibitory potential in Danio rerio

Norantea guianensis Aubl., commonly referred to as the parrot flower or macaw-tail vine, is a plant species found in the Brazilian Amazon, Caatinga, and Cerrado biomes. It is used in folk medicine for its anxiolytic properties, as well as its ability to alleviate headaches and reduce fever. Nevertheless, despite its therapeutic benefits, the impact on embryonic development has yet to be fully explained. The objective of this study was to evaluate chemical constituents by HPLC-DAD, UV-visible and classical phytochemistry and the LC50 of ethanolic extracts from the stem and leaves of N. guianensis in Danio rerio after 96 h and to investigate their effect on developmental morphology. The findings were then related to both Acetylcholinesterase (AChE) activity and the plant's chemical composition. Zebrafish embryos were exposed to 0, 20, 40, 60, 80 and 100 mg/L concentrations of stem and leaves extracts. Phytochemical analysis revealed that the stem extract contained predominantly phenolic compounds, tannins, and anthraquinones, while the leaf extract contained alkaloids and flavonoids. The LC50 values for the stem and leaf extracts were 64.55 mg/L and 7.16 mg/L, respectively, being the stem extract was more toxic than the leaf extract. Induced malformations and alterations in the zebrafish development in different concentrations for both extract including pericardial edema, increased heart rate, spinal malformation and equilibrium disruption. Unlike to stem extract, the leaf extract delayed larval hatching and inhibited AChE activity. The findings indicate that the leaf extract possesses higher embryotoxicity and its use should be avoided during pregnancy.

Graphite Phase Carbon Nitride Nanosheets-Based Fluorescent Sensors for Analysis and Detection

Fluorescent sensors reflect information such as the concentration or content of the analysis by interacting with a specific recognition group to change the signal of the fluorophore. It has attracted much attention because of its advantages of high sensitivity, fast detection speed and low cost, and it has become an effective alternative to traditional detection methods. Graphitic phase carbon nitride nanosheets (g-CNNs) are a class of carbon-based fluorescent nanomaterials derived from bulk graphite phase carbon nitride (g-C3N4), which have attracted much attention from scholars because of their advantages of low cost, simple fabrication, high quantum yield, strong stability and nontoxicity. Functional modified g-CNNs can greatly improve the photocatalytic performance. At present, although there have been some researches on fluorescent sensors based on g-CNNs. Nevertheless, there are few reviews about the g-CNNs-based fluorescent sensors. Therefore, in addition to summarizing the sensing mechanism of fluorescent sensors (such as photoinduced electron transfer, fluorescence resonance energy transfer, and intramolecular charge transfer) and the advantages and disadvantages of common signal substances, this paper focused on the application progress of g-CNNs-based fluorescent sensors in the field of analysis and detection.

Shifts in the spatiotemporal profile of inflammatory phenotypes of innate immune cells in the rat brain following acute intoxication with the organophosphate diisopropylfluorophosphate

Acute intoxication with cholinesterase inhibiting organophosphates (OP) can produce life-threatening cholinergic crisis and status epilepticus (SE). Survivors often develop long-term neurological consequences, including spontaneous recurrent seizures (SRS) and impaired cognition. Numerous studies implicate OP-induced neuroinflammation as a pathogenic mechanism contributing to these chronic sequelae; however, little is known about the inflammatory phenotype of innate immune cells in the brain following acute OP intoxication. Thus, the aim of this study was to characterize the natural history of microglial and astrocytic inflammatory phenotypes following acute intoxication with the OP, diisopropylfluorophosphate (DFP). Adult male and female Sprague-Dawley rats were administered a single dose of DFP (4 mg/kg, sc) followed by standard medical countermeasures. Within minutes, animals developed benzodiazepine-resistant SE as determined by monitoring seizures using a modified Racine scale. At 1, 3, 7, 14, and 28 d post-exposure (DPE), neuroinflammation was assessed using translocator protein (TSPO) positron emission tomography (PET) and magnetic resonance imaging (MRI). In both sexes, we observed consistently elevated radiotracer uptake across all examined brain regions and time points. A separate group of animals was euthanized at these same time points to collect tissues for immunohistochemical analyses. Colocalization of IBA-1, a marker for microglia, with iNOS or Arg1 was used to identify pro- and anti-inflammatory microglia, respectively; colocalization of GFAP, a marker for astrocytes, with C3 or S100A10, pro- and anti-inflammatory astrocytes, respectively. We observed shifts in the inflammatory profiles of microglia and astrocyte populations during the first month post-intoxication, largely in hyperintense inflammatory lesions in the piriform cortex and amygdala regions. In these areas, iNOS+ proinflammatory microglial cell density peaked at 3 and 7 DPE, while anti-inflammatory Arg1+ microglia cell density peaked at 14 DPE. Pro- and anti-inflammatory astrocytes emerged within 7 DPE, and roughly equal ratios of C3+ pro-inflammatory and S100A10+ anti-inflammatory astrocytes persisted at 28 DPE. In summary, microglia and astrocytes adopted mixed inflammatory phenotypes post-OP intoxication, which evolved over one month post exposure. These activated cell populations were most prominent in the piriform and amygdala areas and were more abundant in males compared to females. The temporal relationship between microglial and astrocytic responses suggests that initial microglial activity may influence delayed, persistent astrocytic responses. Further, our findings identify putative windows for inhibition of OP-induced neuroinflammatory responses in both sexes to evaluate the therapeutic benefit of anti-inflammation in this context.

Impact of diethyl phthalate on freshwater planarian behaviour, regeneration, and antioxidant defence

Diethyl phthalate (DEP) has been widely used as a plasticiser in various consumer products, including cosmetics, personal care items, and pharmaceuticals, and recent studies reported a higher abundance of this priority phthalate in the aquatic environment. DEP is a potential endocrine disruptor, affecting immune systems in humans and wildlife even at low-level chronic exposure. As concern over phthalates increases globally, regulatory bodies focus more on their environmental impact. However, limited research is available, particularly using model organisms like planarians. Planarians are ideal for toxicological studies and may provide insightful information on pollutants' neurotoxic, developmental, and ecological effects, especially in freshwater environments where planarians play a vital role in ecosystem balance. Therefore, the objective of the current study was to examine the toxicity of DEP using the freshwater Dugesia sp., as an experimental animal. The LC50 for the test organism was calculated using DEP concentrations of 800, 400, 200, 100, and 50 µM, with an estimated LC50 of 357.24 µM. Furthermore, planarians were exposed to sub-lethal DEP concentration (178.62 µM) for one day as well as eight days to evaluate the impact of DEP on planarian locomotion, feeding behaviour, and regeneration ability. At sub-lethal concentration, locomotion and feeding ability were decreased, and regeneration was delayed. Furthermore, neuro-transmittance in planaria was altered by sub-lethal DEP concentration, as indicated by a reduced acetylcholinesterase (AChE) activity. DEP exposure induced oxidative damage in the tested planarians as shown by a marked increase in stress biomarkers, including lipid peroxidation levels and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), and glutathione S-transferase (GST). Our study revealed that DEP exposure may prove fatal to freshwater organisms, such as planarians. The observed alterations in behaviour and regeneration ability demonstrate the severity of the effects exerted by DEP as a toxicant in aquatic ecosystems, thereby indicating the need to restrict its usage to protect aquatic environments.

Neuropeptide inactivation regulates egg-laying behavior to influence reproductive health in Caenorhabditis elegans

Neural communication requires both fast-acting neurotransmitters and neuromodulators that function on slower timescales to communicate. Endogenous bioactive peptides, often called "neuropeptides," comprise the largest and most diverse class of neuromodulators that mediate crosstalk between the brain and peripheral tissues to regulate physiology and behaviors conserved across the animal kingdom. Neuropeptide signaling can be terminated through receptor binding and internalization or degradation by extracellular enzymes called neuropeptidases. Inactivation by neuropeptidases can shape the dynamics of signaling in vivo by specifying both the duration of signaling and the anatomic path neuropeptides can travel before they are degraded. For most neuropeptides, the identity of the relevant inactivating peptidase(s) is unknown. Here, we established a screening platform in C. elegans utilizing mass spectrometry-based peptidomics to discover neuropeptidases and simultaneously profile the in vivo specificity of these enzymes against each of more than 250 endogenous peptides. We identified NEP-2, a worm ortholog of the mammalian peptidase neprilysin-2, and demonstrated that it regulates specific neuropeptides, including those in the egg-laying circuit. We found that NEP-2 is required in muscle cells to regulate signals from neurons to modulate both behavior and health in the reproductive system. Taken together, our results demonstrate that peptidases, which are an important node of regulation in neuropeptide signaling, affect the dynamics of signaling to impact behavior, physiology, and aging.

Effects of Free and Nanoencapsulated Benznidazole in Acute Trypanosoma cruzi Infection: Role of Cholinergic Pathway and Redox Status

Background/Objectives: The Trypanosoma cruzi infection promotes an intense inflammatory process that affects several tissues. The cholinergic system may exert a regulatory immune response and control the inflammatory process. This study aimed to evaluate the comparative effect of free and nanoencapsulated benznidazole in acute T. cruzi infection to assess hematological, biochemical, and oxidative status triggered by the cholinergic system. Methods: For this, fifty female Swiss mice were distributed in eight groups, i.e., uninfected and infected animals under four treatment protocols: untreated (control-CT); vehicle treatment (Eudragit L 100-EL-100); benznidazole treatment (BNZ); and nanoencapsulated benznidazole treatment (NBNZ). After eight treatment days, the animals were euthanized for sample collection. Results: The peak of parasitemia was at day 7 p.i., and the BNZ and NBNZ controlled and reduced the parasite rate but showed no efficacy in terms of total elimination of parasites analyzed by RT-PCR in both infected groups. The infection promotes significant anemia, leukopenia, and thrombocytopenia, which the BNZ improves. There was an increase in AChE activity during infection, leading to a pro-inflammatory response and an increase in M1 and M2 mACh receptors in the BNZ group, showing that the treatment interacted with the cholinergic pathway. In addition, a pro-oxidative response was characterized in the infection and mainly in the infected BNZ and NBNZ groups. The histopathological analysis showed significative splenomegaly and inflammatory infiltrate in the heart, liver, and spleen. Conclusions: The administration of the BNZ or NBNZ reverses hematological, hepatic, and renal alterations through cholinergic signaling and stimulates a pro-inflammatory response during acute T. cruzi infection.

Combinatorial accumulation, stress response, detoxification and synaptic transmission effects of cadmium and selenium in clams Ruditapes philippinarum

This study investigated the toxicological effects and mechanisms of cadmium (Cd) (5 and 50 μg/L) and selenium (Se) (3 and 30 μg/L) at environmentally relevant concentrations on the gills and digestive glands of clams Ruditapes philippinarum. Results indicated that Cd and Se could tissue-specifically impact osmoregulation, energy metabolism, and synaptic transmission in the gills and digestive glands of clams. After exposure to 50 μg/L Cd, the digestive glands of clams up-regulated the expression of methionine-gamma-lyase and metallothionein for detoxification. Clam digestive glands exposed to 3 μg/L Se up-regulated the expression of catalase and glutathione peroxidase to alleviate oxidative stress, and down-regulated the expression of selenide-water dikinase to reduce the conversion of inorganic Se. Additionally, the interaction mode between Cd and Se largely depended on their molar ratio, with a ratio of 11.71 (50 μg/L Cd + 3 μg/L Se) demonstrated to be particularly harmful, as manifested by significantly more lesions, oxidative stress, and detoxification demand in clams than those exposed to Cd or Se alone. Collectively, this study revealed the complex interaction patterns and mechanisms of Cd and Se on clams, providing a reference for exploring their single and combined toxicity.

Treatment with Blackberry Extract and Metformin in Sporadic Alzheimer's Disease Model: Impact on Memory, Inflammation, Redox Status, Phosphorylated Tau Protein and Insulin Signaling

Natural products offer promising potential for the development of new therapies for Alzheimer's disease (AD). Blackberry fruits are rich in phytochemical compounds capable of modulating pathways involved in neuroprotection. Additionally, drug repurposing and repositioning could also accelerate the development of news treatments for AD. In light of the reduced brain glucose metabolism in AD, an alternative approach has been the use of the drug metformin. Thus, the aim of this study was to evaluate the effect of treatment with blackberry extract in a model of AD induced by streptozotocin (STZ) and compare it with metformin treatment. Male rats were divided into groups: I - Control; II - STZ; III - STZ + blackberry extract (100 mg/kg); IV - STZ + blackberry extract (200 mg/kg) and V - STZ + metformin (150 mg/kg). The animals received intracerebroventricular injection of STZ or buffer. Seven days after the surgical procedure, the animals were treated orally with blackberry extract or metformin for 21 days. Blackberry extract and metformin prevented the memory impairment induced by STZ. In animals of group II, an increase in acetylcholinesterase activity, phosphorylated tau protein, IL-6, oxidative damage, and gene expression of GSK-3β and Nrf2 was observed in the hippocampus. STZ induced a decrease in IL-10 levels and down-regulated the gene expression of Akt1, IRS-1 and FOXO3a. Blackberry extract and metformin prevented the alterations in acetylcholinesterase activity, IL-6, GSK3β, Nrf2, and oxidative damage. In conclusion, blackberry extract exhibits multi-target actions in a model of AD, suggesting new therapeutic potentials for this neurodegenerative disease.

In vivo assessment of oxidative stress, neurotoxicity and histological alterations induction in the marine gastropod Stramonita haemastoma exposed to Cr2O3 and Al2O3 nanoparticles

The increased use of nanoparticles (NPs) is expected to raise their presence in the marine ecosystem, which is considered as the final destination of released NPs. This study investigated the toxicity of Cr2O3 (42 nm) and Al2O3 (38 nm) NPs (1, 2.5, and 5 mg/L) on the digestive glands of Stramonita haemastoma for 7, 14, and 28 days by oxidative stress biomarkers, neurotoxicity indicator assessment, and histological study. Results revealed an imbalance in antioxidants at all periods. Following 7 days, both NPs caused GSH depletion with marked impacts from Al2O3. GPx, CAT, and AChE were also decreased with the highest changes induced by Cr2O3. Both NPs inducted GSH and GST levels on days 14 and 28, with more effects from Cr2O3 exposure. GPx, AChE, and MDA induction were observed on day 28, while MT varied through NPs and time, with imbalanced levels at all periods noticed, SOD was mostly not affected. Histology revealed alterations including necrosis and interstitial deteriorations; quantitative analysis through the histological condition index revealed dose-dependent impacts, with the highest values attributed to Cr2O3 exposure. While PCA revealed the co-response of GSH, GST, GPx, CAT, and AchE with separated MT responses. This study reported oxidative stress induction through a multi-biomarkers investigation, neurotoxicity, and histological damages in the digestive gland of S. haemastoma following Cr2O3 and Al2O3 NPs exposure.

Sequence analysis, homology modeling, tissue expression, and potential functions of seven putative acetylcholinesterases in the spider Cupiennius salei

Acetylcholine esterases (AChEs) are essential enzymes in cholinergic synapses, terminating neurotransmission by hydrolysing acetylcholine. While membrane bound AChEs at synaptic clefts efficiently perform this task, soluble AChEs are less stable and effective, but function over broader areas. In vertebrates, a single gene produces alternatively spliced forms of AChE, whereas invertebrates often have multiple genes, producing both enzyme types. Despite their significance as pesticide targets, the physiological roles of invertebrate AChEs remain unclear. Here, we characterized seven putative AChEs in the wandering spider, Cupiennius salei, a model species for neurophysiological studies. Sequence analyses and homology modeling predicted CsAChE7 as the sole stable, membrane-bound enzyme functioning at synaptic clefts, while the others are likely soluble enzymes. In situ hybridization of sections from the spider's nervous system revealed CsAChE7 transcripts co-localizing with choline acetyltransferase in cells that also exhibited AChE activity. CsAChE7 transcripts were also found in rapidly adapting mechanosensory neurons, suggesting a role in precise and transient activation of postsynaptic cells, contrasting with slowly adapting, also cholinergic, neurons expressing only soluble AChEs, which allow prolonged activation of postsynaptic cells. These findings suggest that cholinergic transmission is influenced not only by postsynaptic receptors but also by the enzymatic properties regulating acetylcholine clearance. We also show that acetylcholine is a crucial neurotransmitter in the spider's visual system and sensory and motor pathways, but absent in excitatory motor neurons at neuromuscular junctions, consistent with other arthropods. Our findings on sequence structures may have implications for the development of neurological drugs and pesticides.

Implications of the non-neuronal cholinergic system for therapeutic interventions of inflammatory skin diseases

The pivotal roles of acetylcholine (ACh) in physiological processes encompass both the nervous and non-neuronal cholinergic systems (NNCS). This review delineates the synthesis, release, receptor interactions, and degradation of ACh within the nervous system, and explores the NNCS in depth within skin cells including keratinocytes, endothelial cells, fibroblasts, macrophages, and other immune cells. We highlight the NNCS's essential functions in maintaining epidermal barrier integrity, promoting wound healing, regulating microcirculation, and modulating inflammatory responses. The potential of the NNCS as a therapeutic target for localized ACh regulation in the skin is discussed, though the translation of these findings into clinical practice remains uncertain due to the complexity of cholinergic signalling and the lack of comprehensive human studies. The review progresses to therapeutic modulation strategies of the NNCS, including AChE inhibitors, nicotinic and muscarinic receptor agonists and antagonists, choline uptake enhancers, and botulinum toxin, highlighting their relevance in dermatology. We highlight the impact of the NNCS on prevalent skin diseases such as psoriasis, atopic dermatitis, rosacea, acne, bullous diseases, hyperhidrosis and hypohidrosis, illustrating its significance in disease pathogenesis and therapy. This comprehensive overview aims to enhance understanding of the NNCS's role in skin health and disease, offering a foundation for future research and therapeutic innovation.

Repurposing of USFDA-approved drugs to identify leads for inhibition of acetylcholinesterase enzyme: a plausible utility as an anti-Alzheimer agent

In the quest to identify new anti-Alzheimer agents, we employed drug repositioning or drug repositioning techniques on approved USFDA small molecules. Herein, we report the structure-based virtual screening (SBVS) of 1880 USFDA-approved drugs. The in silico-based identification was followed by calculating Prime MMGB-SA binding energy and molecular dynamics simulation studies. The cumulative analysis led to identifying domperidone as an identified hit. Domperidone was further corroborated in vitro using anticholinesterase-based assessment, keeping donepezil as a positive control. The analysis revealed that the identified lead (domperidone) could induce an inhibitory effect on AChE in a dose-dependent manner with an IC50 of 3.67 μM as compared to donepezil, which exhibited an IC50 of 1.37 μM. However, as domperidone is known to have poor BBB permeability, we rationally proposed new analogues utilizing the principles of bioisosterism. The bioisostere-clubbed analogues were found to have better BBB permeability, affinity, and stability within the catalytic domain of AChE via molecular docking and dynamics studies. The proposed bioisosteres may be synthesized in the future. They may plausibly be explored for their implication in the developmental progress of new anti-Alzheimer agent achieved via repurposing techniques in future.

Exposure to the herbicide tebuthiuron affects behavior, enzymatic activity, morphology and physiology of the midgut of the stingless bee Partamona helleri

Partamona helleri is an important pollinator in the Neotropics. However, this bee faces an increased risk of pesticide exposure, potentially affecting both individual bees and entire colonies. Thus, this study aimed to evaluate the effects of the herbicide tebuthiuron on behavior, antioxidant activity, midgut morphology, and signaling pathways related to cell death, cell proliferation and differentiation in P. helleri workers. tebuthiuron significantly reduced locomotor activity and induced morphological changes in the midgut. The activity of the detoxification enzymes superoxide dismutase and glutathione S-transferase increased after exposure, indicating a detoxification mechanism. Furthermore, the herbicide led to alterations in the number of positive cells for signaling-pathway proteins in the midgut of bees, suggesting induction of apoptotic cell death and disruption of midgut epithelial regeneration. Therefore, tebuthiuron may negatively impact the behavior, antioxidant activity, morphology, and physiology of P. helleri workers, potentially posing a threat to the survival of this non-target organism.

Discovery of cinnamamide/ester triazole hybrids as potential treatment for Alzheimer's disease

Developing multitargeted ligands as promising therapeutics for Alzheimer's disease (AD) has been considered important. Herein, a novel class of cinnamamide/ester-triazole hybrids with multifaceted effects on AD was developed based on the multitarget-directed ligands strategy. Thirty-seven cinnamamide/ester-triazole hybrids were synthesized, with most exhibiting significant inhibitory activity against Aβ-induced toxicity at a single concentration in vitro. The most optimal hybrid compound 4j inhibited copper-induced Aβ toxicity in AD cells. its action was superior to that of donepezil and memantine. It also moderately inhibited intracellular AChE activity and presented favorable bioavailability and blood-brain barrier penetration with low toxicity in vivo. Of note, it ameliorated cognitive impairment, neuronal degeneration, and Aβ deposition in Aβ1-42-injured mice. Mechanistically, the compound regulated APP processing by promoting the ADAM10-associated nonamyloidogenic signaling and inhibiting the BACE1-mediated amyloidogenic pathway. Moreover, it suppressed intracellular AChE activity and tau phosphorylation. Therefore, compound 4j may be a promising multitargeted active molecule against AD.

New insights about the toxicity of 2,4-D: Gene expression analysis reveals modulation on several subcellular responses in Chironomus riparius

Herbicides are the main class of pesticides applied in crops and are capable of polluting the surrounding freshwater system; thus, understanding their impact on non-target species, whose mechanism of action is not described, helps to elucidate the real risks of these pollutants to the environment. 2,4-dichlorophenoxyacetic acid (2,4-D) is frequently detected in water and, due to its persistence, poses a risk to wildlife. In this way, the present work aimed to describe the implication of exposure to concentrations of 2,4-D already reported in aquatic environments in several physiological mechanisms of C. riparius at molecular and biochemical levels. To achieve this, bioassays were conducted with fourth instar larvae exposed to three concentrations of 2,4-D (0.1, 1.0, and 7.5 μg L-1). Larvae were collected after 24 and 96 h of exposure, and the expression of 42 genes, related to six subcellular mechanisms, was assessed by Real-Time PCR (RT-PCR). Besides, the activity of the enzymes catalase (CAT), glutathione S-transferase (GST), and acetylcholinesterase (AChE) was determined. The main metabolic route altered after exposure to 2,4-D was the endocrine system (mainly related to 20-hydroxyecdysone and juvenile hormone), confirming its endocrine disruptor potential. Four of the eleven stress response genes studied were down-regulated, and later exposure modulated DNA-repair genes suggesting genotoxic capacity. Moreover, only one gene from each detoxification phase was modulated at short exposure to 1.0 μg L-1. The molecular responses were not dose-dependent, and some early responses were not preserved after 96 h, indicating a transient response to the herbicide. Exposure to 2,4-D did not alter the activity of CAT, GST, and AChE enzymes. The responses described in this study reveal new mechanistic pathways of toxicity for 2,4-D in non-target organisms and highlight potential ecological consequences for chironomids in aquatic systems at the edges of agricultural fields.

Pharmacological Treatments for Methamphetamine Use Disorder: Current Status and Future Targets

The illicit use of the psychostimulant methamphetamine (METH) is a major concern, with overdose deaths increasing substantially since the mid-2010s. One challenge to treating METH use disorder (MUD), as with other psychostimulant use disorders, is that there are no available pharmacotherapies that can reduce cravings and help individuals achieve abstinence. The purpose of the current review is to discuss the molecular targets that have been tested in assays measuring the physiological, the cognitive, and the reinforcing effects of METH in both animals and humans. Several drugs show promise as potential pharmacotherapies for MUD when tested in animals, but fail to produce long-term changes in METH use in dependent individuals (eg, modafinil, antipsychotic medications, baclofen). However, these drugs, plus medications like atomoxetine and varenicline, may be better served as treatments to ameliorate the psychotomimetic effects of METH or to reverse METH-induced cognitive deficits. Preclinical studies show that vesicular monoamine transporter 2 inhibitors, metabotropic glutamate receptor ligands, and trace amine-associated receptor agonists are efficacious in attenuating the reinforcing effects of METH; however, clinical studies are needed to determine if these drugs effectively treat MUD. In addition to screening these compounds in individuals with MUD, potential future directions include increased emphasis on sex differences in preclinical studies and utilization of pharmacogenetic approaches to determine if genetic variances are predictive of treatment outcomes. These future directions can help lead to better interventions for treating MUD.

Does copper contamination change thermotaxis of the soil arthropod Folsomia candida (Collembola)?

Behavioural thermoregulation (thermotaxis) is essential for soil invertebrates to evade thermal extremes in terrestrial environments. Extensive and continuous use of copper (Cu) based products has led to elevated Cu concentration in soils across the globe and in some areas reaching concentrations that are hazardous to soil invertebrates. We hypothesised that environmental stressors, for example, exposure to heavy metals may compromise the adaptive behavioural thermoregulation of organisms, but very little is known of such interactions. In this study, we chose Cu as a model toxicant and investigated the potential effect of Cu-contaminated soils on the behavioural thermoregulation of springtails (Folsomia candida). We measured the distribution of springtails when placed on a temperature gradient ranging from 6 to 46 °C and estimated their thermal preference as an indicator of behavioural thermoregulation. Results showed that within 60 min of being introduced to the thermal gradient, the distribution of springtails was unimodal with slight skewness towards high temperature. Springtails exhibited a consistent preferred temperature range of approximately 21-23 °C across all Cu exposure levels and time points. However, Cu contamination increased the frequency of springtails recorded along the gradient where temperature was above 30 °C. We interpreted this observation as Cu-exposed animals having an elevated risk of entering heat coma and not being able to evade noxious temperatures. We conclude that Cu contamination does not alter the thermal preference of F. candida but compromises their ability to tolerate extreme high temperature. Incorporating behavioural responses into ecotoxicological assessments provides ecologically relevant insights into the impacts of chemical pollution on soil ecosystems.

Evaluation of Developmental Toxicity and Oxidative Stress Caused by Zinc Oxide Nanoparticles in Zebra Fish Embryos/ Larvae

Zinc oxide nanoparticles (ZnO NPs) are used in various fields, including biological ones. ZnO NPs are eventually disposed of in the environment where they may affect natural systems, and there is no international law to regulate their manufacture, usage, and disposal. Hence, this present study is carried out to synthesise a more non-toxic and bioactive ZnO NPs from the marine algae Sargassum polycystum. The ZnO NPs were biologically produced using the marine algae Sargassum polycystum. The dynamic light scattering result describes that synthesised particles' average size is about 100 nm in diameter. Transmission electron microscopy (TEM) analysis demonstrated the rod-like morphology of ZnO NPs. Fourier tranform-infrared spectroscopy (FT-IR) results revealed the presence of functional groups in ZnO NPs. The selected area electron diffraction (SAED) results strongly suggested the ZnO NPs crystallinity. ZnO NPs surface morphology and compositions were identified by scanning electron microscopy (SEM- EDX) values. To analyse the toxicity of synthesised nanoparticles, zebra fish larvae were used, which involved subjecting embryos to various ZnO NPs concentrations at 1 hpf and analysing the results at 96 hpf. The 60 and 80 ppm sub-lethal doses were chosen for further studies based on the LC50 (82.23 ppm). In the ZnO NPs-treated groups, a significant slowdown in pulse rate and a delay in hatching were seen, both of which impacted the embryonic processes. A teratogenic study revealed a dose-dependent increase in the incidence of developmental deformities in the treated groups. Along with increased oxidants and a corresponding reduction in antioxidant enzymes, Na+ K+-ATPase and AChE activity changes were seen in ZnO NPs-treated zebra fish larvae groups. The apoptosis process was increased in ZnO NPs-treated groups revealed by acridine orange staining. These results indicate that the green synthesis process cannot mitigate the oxidative stress induced by ZnO NPs on oxidative signalling.

Exploring the Combined Effect of Exercise and Apigenin on Aluminium-Induced Neurotoxicity in Zebrafish

Aluminium (AL) is a strong environmental neurotoxin linked to neurodegenerative disorders. Widespread industrial use leads to its presence in water systems, causing bioaccumulation in organisms. This, in turn, results in the bioaccumulation of AL in various organisms. Several studies have highlighted the benefits of enhanced physical activity in combating neurodegenerative diseases. Meanwhile widespread presence of apigenin in aquatic environment has been largely overlooked, in terms of its potential to counter AL-induced neurotoxicity. The combined impact of exercise and apigenin in mitigating the effects of AL-induced neurotoxicity in aquatic animals remains unexplored. Hence, the objective of this study is to determine whether the combined treatment of exercise and apigenin can effectively alleviate the chronic neurotoxicity induced by AL. Zebrafish that were exposed to AL showed behaviours resembling anxiety, increased aggression, unusual swimming pattern, and memory impairment, which are typical features observed in Alzheimer's disease (AD)-like syndrome. Combined treatment of exercise and apigenin protects zebrafish from AL-induced neurotoxicity, which was measured by improvements in memory, reduced anxiety and aggression, and increased levels of antioxidant enzymes and acetylcholinesterase (AChE) activity. Furthermore, AL exposure is associated with increased expression of genes related to neuroinflammation and AD. However, synergistic effect of exercise and apigenin counteract this effect in AL-treated zebrafish. These findings suggest that AL is involved in neurodegenerative diseases in fish, which could affect the integrity of aquatic ecosystem. Hence, there is a strong correlation between enhanced physical activity, apigenin, and the well-being of the ecosystem.

A second hit by PFOS exposure exacerbated developmental defects in medaka embryos with a history of ancestral BPA exposure

Bisphenol-A (BPA), a known endocrine-disrupting chemical (EDC) in plastics and resins, has been found to induce heritable health effects in fish and mammals, affecting directly exposed individuals and indirectly their progenies in subsequent generations. It is not clearly understood if subsequent generations of the BPA-exposed ancestors have increased sensitivity to the second hit by the chemicals of emerging concern. To understand this, the present study examined the effects of developmental exposure to perfluorooctanesulfonic acid (PFOS), which has been a global contaminant recently, in embryos whose ancestors were exposed to BPA. Two lineages of medaka (Oryzias latipes) were established: 1) the BPA lineage in which the F0 generation was exposed to 10 μg/L BPA during early development and 2) the control lineage with no BPA exposure in the F0 generation. These lineages were raised up to the F4 generation without further exposure. The embryos of the F4 generation were exposed to PFOS at 0, 0.002, 0.02, 0.2, 2, and 20 mg/L concentrations. Early developmental defects resulting in mortality, delayed hatching, teratogenic phenotypes, and altered gene expression were examined in both lineages. The expression level of genes encoding DNA methyltransferases and genes responsible for oxidative stress defense were determined. Following environmentally relevant PFOS exposure, organisms with a history of BPA exposure displayed significant changes in all categories of developmental defects mentioned above, including increased expression of genes related to oxidative stress, compared to individuals without BPA exposure. The present study provides initial evidence that a history of ancestral BPA exposure can alter sensitivity to developmental disorders following the second hit by PFOS exposure. The variable of ancestral BPA exposure could be considered in mechanistic, medical, and regulatory toxicology, and can also be applied to holistic environmental equity research.

Pre-Adsorbed H-Mediated Electrochemiluminescence

In conventional electrochemiluminescence (ECL) systems, the presence of the competitive cathodic hydrogen evolution reaction (HER) in aqueous electrolytes is typically considered to be a side reaction, leading to a reduced ECL efficiency and stability due to H2 generation and aggregation at the electrode surface. However, the significant role of adsorbed hydrogen (H*) as a key intermediate, formed during the Volmer reaction in the HER process, has been largely overlooked. In this study, employing the luminol-H2O2 system as a model, we for the first time demonstrate a novel H*-mediated coreactant activation mechanism, which remarkably enhances the ECL intensity. H* facilitates cleavage of the O-O bond in H2O2, selectively generating highly reactive hydroxyl radicals for efficient ECL reactions. Experimental investigations and theoretical calculations demonstrate that this H*-mediated mechanism achieves superior coreactant activation compared to the conventional direct electron transfer pathway, which unveils a new pathway for coreactant activation in the ECL systems.

Reaction, Recognition, Relay: Anhydride Hydrolysis Reported by Conformationally Responsive Fluorinated Foldamers in Micelles

Natural membrane receptors are proteins that can report on changes in the concentration of external chemical messengers. Messenger binding to a receptor produces conformational changes that are relayed through the membrane into the cell; this information allows cells to adapt to changes in their environment. Artificial membrane receptors (R)-1 and (S)-1 are helical α-aminoisobutyric acid (Aib) foldamers that replicate key parts of this information relay. Solution-phase 19F NMR spectroscopy of zinc(II)-capped receptor 1, either in organic solvent or in membrane-mimetic micelles, showed messenger binding produced an enrichment of either left- or right-handed screw-sense; the chirality of the bound messenger was relayed to the other receptor terminus. Furthermore, in situ production of a chemical messenger in the external aqueous environment could be detected in real-time by a racemic mixture of receptor 1 in micelles. The hydrolysis of insoluble anhydrides produced carboxylate in the aqueous phase, which bound to the receptors and gave a distinct 19F NMR output from inside the hydrophobic region of the micelles.

Pnictogen bond-driven control of the molecular interaction between organophosphorus and acetylcholinesterase enzyme

This study addresses a comprehensive assessment of the interaction between chemical warfare agents (CWA) and acetylcholinesterase (AChE) systems, focus on the intriguing pnictogen-bond interaction (PnB). Utilizing the crystallographic data from the Protein Data Bank pertaining to the AChE-CWA complex involving Sarin (GB), Cyclosarin (GF), 2-[fluoro(methyl)phosphoryl]oxy-1,1-dimethylcyclopentane (GP) and venomous agent X (VX) agents, the CWA is systematically displaced by increments of 0.1 Å along the PO bond axis, extending its distance by 4 Å from the original position. The AIM analysis was carried out and consistently revealed the presence of a significant interaction along the PO bond. Investigating the intrinsic nature of the PnB, the NBO and the EDA analysis unearthed the contribution of orbital factors to the overall energy of the system. Strikingly, this observation challenges the conventional σ-hole explanation commonly associated with such interactions. This finding adds a layer of complexity to understanding of PnB, encouraging further exploration into the underlying mechanisms governing these intriguing chemical phenomena.

Rodent Models of Alzheimer's Disease: Past Misconceptions and Future Prospects

Alzheimer's disease (AD) is a progressive neurodegenerative disease with no effective treatments, not least due to the lack of authentic animal models. Typically, rodent models recapitulate the effects but not causes of AD, such as cholinergic neuron loss: lesioning of cholinergic neurons mimics the cognitive decline reminiscent of AD but not its neuropathology. Alternative models rely on the overexpression of genes associated with familial AD, such as amyloid precursor protein, or have genetically amplified expression of mutant tau. Yet transgenic rodent models poorly replicate the neuropathogenesis and protein overexpression patterns of sporadic AD. Seeding rodents with amyloid or tau facilitates the formation of these pathologies but cannot account for their initial accumulation. Intracerebral infusion of proinflammatory agents offer an alternative model, but these fail to replicate the cause of AD. A novel model is therefore needed, perhaps similar to those used for Parkinson's disease, namely adult wildtype rodents with neuron-specific (dopaminergic) lesions within the same vulnerable brainstem nuclei, 'the isodendritic core', which are the first to degenerate in AD. Site-selective targeting of these nuclei in adult rodents may recapitulate the initial neurodegenerative processes in AD to faithfully mimic its pathogenesis and progression, ultimately leading to presymptomatic biomarkers and preventative therapies.

Biopesticide spinosad: Unraveling ecotoxicological effects on zebrafish, Danio rerio

Biopesticides are natural compounds considered more safe and sustainable for the environment. Spinosad (SPI) is a bioinsecticide used in marketed worldwide, to eradicate a variety of pests. This study aimed to assess the impacts of the SPI on the non-target organism zebrafish (Danio rerio). Several concentrations of SPI were tested to evaluate the acute (0.07-1.0 mg/L) and chronic (0.006-0.100 mg/L) ecotoxicological effects. To evaluate sub-individual effects, antioxidant defense, lipid peroxidation, energy sources, and cholinergic biomarkers were quantified. In both exposures, SPI induced significant effects on antioxidant defense indicating oxidative stress, disrupting energy pathways, and exhibiting neurotoxic effects, under environmentally relevant conditions. Integrated Biomarker Response (IBRv2) showed that with increasing SPI concentrations, an increase in impacts on organisms was recorded. This study demonstrates the vulnerability of a non-target organism to SPI, a bioinsecticide considered environmentally safe. Further research is essential to fully understand the implications of spinosad to aquatic biota.

Amyloid Beta Leads to Decreased Acetylcholine Levels and Non-Small Cell Lung Cancer Cell Survival via a Mechanism That Involves p38 Mitogen-Activated Protein Kinase and Protein Kinase C in a p53-Dependent and -Independent Manner

Several studies have shown an inverse correlation between the likelihood of developing a neurodegenerative disorder and cancer. We previously reported that the levels of amyloid beta (Aβ), at the center of Alzheimer's disease pathophysiology, are regulated by acetylcholinesterase (AChE) in non-small cell lung cancer (NSCLC). Here, we examined the effect of Aβ or its fragments on the levels of ACh in A549 (p53 wild-type) and H1299 (p53-null) NSCLC cell media. ACh levels were reduced by cell treatment with Aβ 1-42, Aβ 1-40, Aβ 1-28, and Aβ 25-35. AChE and p53 activities increased upon A549 cell treatment with Aβ, while knockdown of p53 in A549 cells increased ACh levels, decreased AChE activity, and diminished the Aβ effects. Aβ increased the ratio of phospho/total p38 MAPK and decreased the activity of PKC. Inhibiting p38 MAPK reduced the activity of p53 in A549 cells and increased ACh levels in the media of both cell lines, while opposite effects were found upon inhibiting PKC. ACh decreased the activity of p53 in A549 cells, decreased p38 MAPK activity, increased PKC activity, and diminished the effect of Aβ on those activities. Moreover, the negative effect of Aβ on cell viability was diminished by cell co-treatment with ACh.