Brain Cholinesterase Activity Research Articles

Alterations of Neurobehavioral Performance, Blood and Brain Cholinesterase Activities and Cholesterol Levels by Repeated Statin Treatments in Mice

Alterations of Neurobehavioral Performance, Blood and Brain Cholinesterase Activities and Cholesterol Levels by Repeated Statin Treatments in Mice

Formulation and characterization of polymeric nanoparticle of Rivastigmine for effective management of Alzheimer’s disease

Memory loss or dementia is a progressive disorder, and one of its common forms is Alzheimer’s disease (AD), effecting mostly middle aged and older adults. In the present study, we developed Rivastigmine (RIV) nanoparticles using poly(lactic-co-glycolic acid) (RIV-loaded PLGA NPs) and polyvinyl alcohol (PVA). The prepared RIV-PLGA nanoparticles was evaluated for the management of Alzheimer's disease (AD). The nanoparticles were prepared by the slightly modified nano-precipitation technique. The developed formulations were evaluated for particle size, zeta potential (ZP), polydispersibility index (PDI) and surface morphology and drug content. The experimental result revealed that prepared RIV-loaded PLGA NPs (F1) was optimized having particle size (61.2 ± 4.6 nm), PDI (0.292), ZP (−11.2 ± 1.2). SEM study confirms the prepared nanoparticles depicted non-aggregated as well smooth surface particles without any fracture. This formulation (F1) was further assessed for in vivo studies on animal model. A pharmacological screening on an animal model of Alzheimer's disease revealed that RIV-loaded PLGA NPs formulations treat CNS disorders like Alzheimer's effectively. In addition to that, an in-vivo brain cholinesterase estimation study found that, animals treated with optimized formulation significantly (p < 0.01) reduced brain cholinesterase activity when compared to scopolamine-treated animals. According to the above results, it can be concluded that RIV-loaded PLGA NPs are ideal carriers for delivering the drug at a specific target site in the brain, thus may treat Alzheimer's disease efficiently and improve patient compliance.

Adverse neurobehavioral changes with reduced blood and brain cholinesterase activities in mice treated with statins.

Pleiotropic effects of hypolipidemic statins with behavioral outcomes have been suggested in humans and laboratory animals. There is limited information on the neurobehavioral effects of statins in mice. The aim of the present study was to examine changes in neurobehavioral performance and cholinesterase (ChE) activity in mice after high doses of three commonly used statins (atorvastatin, simvastatin, and rosuvastatin). Two hours after vehicle (control) or statin dosing at 250, 500, 750, or 1000 mg/kg orally, each mouse was subjected to 5 min open-field activity, negative geotaxis at an angle of 45°/60 s, 5 min head pocking, and forced swimming endurance. Plasma, erythrocyte, and brain ChE activities were determined spectrophotometrically 2 and 24 h after oral dosing of statins at 500 and 1000 mg/kg. The statins variably, but dose-dependently and significantly (p < 0.05) delayed the latency to move in the open-field arena, decreased locomotion and rearing, reduced head pocking, and delayed negative geotaxis performance. However, statins significantly increased the duration of forced swimming and decreased the duration of immobility in the swimming tank. Statins significantly and dose-dependently decreased plasma, erythrocyte, and brain ChE activity 2 and 24 h after dosing. Plasma and brain ChE activities recovered by 5%-32.9% and 5.7%-14.4% 24 h later from the 2 h ChE values, respectively. High doses of statins differentially modulate neurobehavioral outcomes in mice in association with reduced plasma, erythrocyte, and brain ChE activity. Plasma or erythrocyte ChE may be used for biomonitoring of the adverse/therapeutic effects of statins.

Fenpropathrin Induces Oxidative Stress, Inhibits Cholinesterase, and Causes Genotoxicity in &lt;i&gt;Pethia conchonius&lt;/i&gt; (Hamilton, 1822)

Pesticide contamination in water bodies is a serious threat to aquatic organisms. Among the new generation pesticides, synthetic pyrethroids enter the aquatic environment from agricultural runoff and are more persistent in aquatic environment. In this study, we investigated the effect of fenpropathrin, a type II pyrethroid, on Pethia conchonius. The median lethal concentration for commercial formulation of fenpropathrin (Danitol®) was determined to be 2.43 μg/L. Based on the median lethal concentration, the fish were exposed to 1/5th (0.486 μg/L) and 1/10th (0.243 μg/L) of median lethal concentrations for 30 days. After the exposure period, antioxidant enzymes status (superoxide dismutase and catalase), oxidative stress parameters (lipid peroxidation and reduced glutathione) in brain, liver, and kidney, cholinesterase enzyme activity in brain and muscles, and incidences of micronucleus were evaluated. In the treatment groups, alteration in antioxidant enzyme levels were observed in brain, liver, and kidney. Lipid peroxidation, which is indicative of oxidative stress, was observed but did not show much variation. Reduced glutathione was also altered. Cholinesterase activity was significantly different in the brain tissues between control and treatment groups; however, no significant difference was observed between the cholinesterase activities of muscles in control and treatment groups. Micronucleus incidence in treatment groups was higher than that in the control. Our study indicates that fenpropathrin altered the antioxidative enzyme status, inhibited cholinesterase activity in brain, and exhibited potential genotoxic effects in the fish Pethia conchonius.

Differential effects of statins on plasma and brain cholinesterase activities in chicks

Statins used to treat dyslipidemia may differentially modulate cholinesterase (ChE) activity impacting neuronal function. This study examines the effects of three statins (atorvastatin, fluvastatin, and simvastatin) on plasma and brain ChE activities and cholesterol levels in a chick model of 7-14 days old. Chicks were dosed orally with single doses of each statin at 50, 100, and 200mg/kg or repeated doses at 100mg/kg/day for 14 consecutive days. Plasma and whole brain ChE activities were measured electrometrically, whereas cholesterol levels were measured using a commercial colourimetric kit. In vitro ChE inhibition by the statins was initiated at 37°C for 10 mins. Data were statistically analysed using analysis of variance followed by the least significant difference test. Atorvastatin and fluvastatin did not significantly affect plasma ChE activities 2 hours after the oral administration, whereas simvastatin at 100 and 200mg/kg significantly increased (28% and 16%, respectively) plasma ChE activity. Repeated oral doses of the statins did not significantly affect plasma ChE activity. However, only simvastatin significantly decreased whole brain ChE activity by 33%. Repeated treatments with the three statins significantly reduced cholesterol levels in the plasma but not in the whole brain. The three statins inhibited in vitro plasma and whole brain ChE activities by 10-33% and 8-43%, respectively. The results suggested that the statins differentially modulated ChE activity in vivo and in vitro in chicks. Additional in vivo studies are warranted on statin effects on ChE activity in different brain regions of animal models.

Assessment of Cholinesterase inhibition activity of birds inhabiting pesticide exposed croplands and protected area in hot semi-arid region of Pakistan.

Acetylcholinesterase (AChE) activity levels can be used as an indicator for AChE inhibition due to pesticide poisoning in bird species. We assessed the comparative brain cholinesterase (AChE) activity level of five bird species inhabiting pesticide exposed croplands and Protected Area i.e. Deva Vatala National Park (DVNP), Bhimber by using a spectrophotometric method. AChE activity levels ranged from 56.3 to 85.9 µmol/min/g of brain tissue of birds representing DVNP. However, AChE activity levels ranged from 27.6 to 79.9 µmol/min/g of brain tissue of birds representing croplands. AChE activity levels observed in Jungle babbler, Common babbler, and Red-vented bulbul showed significant differences (P < 0.05) at two sites. However, White wagtail and Black drongo demonstrated non-significant differences (P > 0.05). Maximum inhibition was recorded in Jungle babbler (53%) followed by Common babbler (35%), Red-vented bulbul (18%), White wagtail (15%), and Black drongo (7%). The brain cholinesterase inhibition levels under-protected ecosystems (DVNP, Bhimber) and agricultural landscape suggest insecticidal contamination and its impact on avifauna diversity. The study also emphasizes on the importance of pesticide-free zones to protect the biodiversity of birds.

Impacts of Dietary Chrysophyllum albidum Fruit Pulp on Brain Cholinesterase Function in High-Fat Diet/Streptozotocin-Induced Diabetic Rats

Epidemiologic studies have shown strong correlations between Alzheimer’s disease and diabetes mellitus. The exact mechanism through which this happens remains unclear. However, the dependence on glucose for brain function has been proposed as one possible mechanism. Hence, this study investigated the neuroprotective potential of Chrysophyllum albidum fruit pulp (CAPP) with hypoglycaemic properties in diabetic rats induced with high-fat diet/streptozotocin (STZ). The animals were grouped into seven units as follows: control, STZ-induced, STZ + metformin (positive control), STZ + 5% CAPP, STZ + 10% CAPP, control + 5% CAPP and control + 10% CAPP and each group was made up of six rats. The animals were first placed on normal diet (non-diabetic groups) and high fat diet (diabetic groups) for a fortnight, respectively before induction with STZ and were treated with diets containing 5 and 10% CAPP for 14 days. After the experiment, the rat brain cholinesterase and antioxidant activities were determined. The results revealed that acetylcholinesterase (AChE), butylcholinesterase (BuChE), arginase, adenosine deaminase (ADA) and antioxidant activities were altered in STZ-diabetic group in comparison to the control. However, a significant decrease at p &lt; 0.05 was found in the activities of AChE, BuChE, arginase and ADA. In addition, there was a concomitant rise in the levels of antioxidant in all the groups administered supplemented diets and the group treated with metformin in comparison to the STZ-diabetic group. Conclusively, we can suggest that the fruit pulp prevents neurological damage in diabetic rats via anticholinesterase activity and improvement of brain antioxidant status.

Recognition and Assessment of Antidotal Effects of Diphenhydramine against Acute Carbaryl Insecticide Poisoning in a Chick Model

Diphenhydramine antagonizes poisoning produced by cholinesterase (ChE) inhibiting insecticides. This study examines the effects of diphenhydramine against acute poisoning induced by the carbamate insecticide carbaryl in a chick model. The effects of diphenhydramine on the 24 h median Lethal Dose (LD50), and acute toxicity of carbaryl were assessed in chicks (7-15 days old). The plasma and whole brain ChE activities were measured electrometrically in vitro and in vivo. Diphenhydramine at 10mg/Kg Body wt. administered intramuscularly 15 min before carbaryl dosing increased the oral LD50 value of carbaryl (207 mg/Kg Body wt.) by 62%. Carbaryl at 250 mg/Kg Body wt. has orally produced toxidrome of cholinergic poisoning with 100% lethality in 24 h. Diphenhydramine (10mg/ Kg Body wt.) used 15 min before carbaryl (250mg/Kg Body wt., orally) was the most effective dose (vs 5 and 20mg/Kg Body wt.) in delaying carbaryl-toxicity and increasing survivals in chicks. The intramuscular median effective dose (ED50) of diphenhydramine which prevented 24 h carbaryl-death in chicks was 8.6mg/ Kg Body wt. The antidotal response to diphenhydramine was similar to that of the standard antidote atropine sulfate. Diphenhydramine at 10mg/Kg Body wt., given immediately after carbaryl (200mg/Kg Body wt.), reduced the percentages of plasma and whole brain ChE inhibitions in vivo by 12- and 13%, respectively. Carbaryl (10μmol/L) in vitro inhibited ChE activities in the plasma and brain by 53 and 77%, respectively; these inhibitions were reduced by 13- and 14%, respectively, when diphenhydramine (10μmol/L) was added to in vitro reactions. Diphenhydramine exerted antidotal action against a model of acute and lethal carbaryl intoxication in chicks.

An integrated biomarker approach: Non-monotonic responses to cadmium exposure in the suckermouth catfish Hypostomus plecostomus

Environmental risk assessment in aquatic ecosystems typically uses biomarkers to detect interactions between potential hazards and biological systems. Next to knowing environmental contaminant levels in tissues and the environment, it is important to link to potentially deleterious effects at higher levels of biological organization such as biochemistry, physiology, and overall health status. In this laboratory study we assessed the toxicity of waterborne cadmium (Cd) over an exposure range of 0 - 100 µg l-1 for nine days to the loricariid suckermouth catfish Hypostomus plecostomus. We evaluated the integrated response of the fish at the biochemical to physiological level by means of a suite of tissue biomarkers of exposure and effects, including Cd concentrations in gills, liver metallothioneins (MT) and cholinesterase activity (ChE) in brain, before and after the inhibition of the alkaloid eserine, as well as whole-fish resting oxygen consumption rates and ingestion rate. Tissue biomarkers (MT and ChE) showed a non-monotonic relationship, with maximum/minimum responses at intermediate doses. i.e. 10 and 50 µg l-1, whereas biomarker responses of fish exposed at 100 µg l-1 more closely resembled biomarker responses seen at lower concentrations (< 10 µg l-1). Conversely, the oxygen consumption rate peaked at 100 µg l-1, suggesting a higher metabolic cost for higher metal exposure, with no significant correlation with fish body condition and food intake. Integrated Biomarker Response (IBR) values peaked at the intermediate exposure concentration of 50 µg l-1 Cd. The non-monotonic dose-response of the biochemical biomarkers of exposure, together with the higher metabolic rates of fish exposed to 50 - 100 µg l-1 of Cd and the non-significant effects on the more relevant physiological and histological variables suggests that H. plecostomus is capable of biochemically and physiologically regulating moderately high Cd concentrations, thus representing a suitable indicator organism to monitor metal pollution by Cd.

Moringa oleifera Ameliorates Chlorpyrifos Induced Oxidative Stress in Male Wistar Rats

Background: Chlorpyrifos is a widely used organophosphate pesticide. It exerts its toxic effect by inhibiting of cholinesterases and induction of oxidative stress. Methods: In the present study,Soya oil, Chlopyrifos,Moringa oleifera, Chlopyrifos + Moringa oleifera, were given to male rats through gavage for 2 weeks.The influence of chlorpyrifos on brain cholinesterase activity and indicators of oxidative stress malondialdehydecatalase, glutathione, superoxide dismutaseand also histopathological changes in the brain of Wistar rats was investigated compared to control group. Results: There was significant increase in the brain malondialdehyde of the chlopyrifos group compared to the control and chlopyrifos+Moringa oleifera group. Also there were significant decreases in the superoxide dismutase, catalase, glutathione and acetylcholinesterase concentrations in the chlopyrifosgroup compared to the control and chlopyrifos + Moringa oleifera group. The rats showed significant changes in body, liver, kidneys and heart weights No significant haematological changes were seen following treatment. While some histopathological changes were detected in brain tissues in the chlopyrifos treated group, less histopathological changes were observed in chlopyrifos +Moringa oleifera treated groups at the end of the 2 weeks’ study. Conclusion: Overall, these results support the hypothesis that chlopyrifos causes oxidative stress and Moringa oleiferaextract can help reduce the changes induced by chlopyrifos.

Micro/nano-plastics cause neurobehavioral toxicity in discus fish (Symphysodon aequifasciatus): Insight from brain-gut-microbiota axis

Numerous studies have investigated neurobehavioral toxicity of microplastics, but no studies have illustrated mechanism via brain-gut axis. Here, juvenile discus fish (Symphysodon aequifasciatus) were exposed for 96 h to microfibers (900 µm, fiber, MFs) or nanoplastics (~88 nm, bead, NPs) with three concentrations (0, 20 and 200 µg/L). Accumulation in fish gut was independent of plastics type and concentration. MFs reduced growth performance while NPs weakened swimming and predatory performance of post-exposed discus. For brain cholinesterase activity, acetylcholinesterase was activated by NPs while NPs/MFs exposure inhibited butyrylcholinesterase. Concentrations of neurotransmitters (acetylcholine, dopamine and γ-aminobutyric acid) increased in brain but decreased in gut after NPs or MFs exposure. For gut microbiota, increased richness under MFs exposure was observed. At phylum level, Proteobacteria proportion was lower in NPs but higher in MFs. Abundance of Clostridia and Fusobacteriia (Bacillus), potentially secreting neurotransmitters, increased in NPs but decreased in MFs. Brain transcriptomics revealed seven upregulated and four downregulated genes concerning neural-activities. Pathways of neuroactive ligand-receptor interaction and serotonergic synapse were enriched in both MFs and NPs, but dopaminergic synapse pathway was enriched only in MFs. These results established a novel mechanism by which microplastics might cause behavioral toxicities via brain-gut-microbiota axis.

Persistent proteomic changes in glutamatergic and GABAergic signaling in the amygdala of adolescent rats exposed to chlorpyrifos as juveniles

Chlorpyrifos (CPF) remains one of the most widely used organophosphorus insecticides (OPs) despite the concerns about its developmental neurotoxicity. Developmental exposure to CPF has long-lasting negative impacts, including abnormal emotional behaviors. These negative impacts are observed at exposure levels do not cause inhibition of acetylcholinesterase, the canonical target of OPs. Exposure to CPF at these levels inhibits the endocannabinoid metabolizing enzyme fatty acid amide hydrolase (FAAH) but it is not clear what the persistent effects of this inhibition are. To investigate this, male rat pups were exposed orally to either corn oil, 0.75 mg/kg CPF, or 0.02 mg/kg PF-04457845 (PF; a specific inhibitor of FAAH) daily from postnatal day 10 (PND10) - PND16. This dosage of CPF does not inhibit brain cholinesterase activity but inhibits FAAH activity. On PND38 (adolescence), the protein expression in the amygdala was determined using a label-free shotgun proteomic approach. The analysis of control vs CPF and control vs PF led to the identification of 44 and 142 differentially regulated proteins, respectively. Gene ontology enrichment analysis revealed that most of the proteins with altered expression in both CPF and PF treatment groups were localized in the synapse-related regions, such as presynaptic membrane, postsynaptic density, and synaptic vesicle. The different biological processes affected by both treatment groups included persistent synaptic potentiation, glutamate receptor signaling, protein phosphorylation, and chemical synaptic transmission. These results also indicated disturbances in the balance between glutamatergic (↓ Glutamate AMPA receptor 2, ↓ Excitatory amino acid transporter 2, and ↑ vesicular glutamate transporter 2) and GABAergic signaling (↑ GABA transporter 3 and ↑ glutamate decarboxylase 2). This imbalance could play a role in the abnormal emotional behavior that we have previously reported. These results suggest that there is a similar pattern of expression between CPF and PF, and both these chemicals can persistently alter emotional behavior as a consequence of inhibition of FAAH.

Early Toxic Effects in a Central American Native Fish (Parachromis dovii) Exposed to Chlorpyrifos and Difenoconazole.

In Costa Rica, agriculture is one of the most important economic activities. Chlorpyrifos and difenoconazole have been identified as agrochemicals widely used in banana and pineapple crops in the Caribbean area of the country and are constantly recorded in aquatic ecosystems. The toxicity of these pesticides in Parachromis dovii was studied. Median lethal concentrations (LC50s) for each substance were obtained from 96-h acute tests. Then, fish were exposed to sublethal concentrations of both substances (10% of LC50), individually and in mixture, to evaluate biomarker responses. Ethoxyresorufin-O-deethylase (EROD), catalase, and glutathione S-transferase activities as well as lipid peroxidation were measured in liver and gill tissues as markers of biotransformation and oxidative stress processes. Cholinesterase activity in brain and muscle tissue was also quantified as a biomarker of toxicity. The LC50s were 55.34 μg/L (95% confidence interval [CI] 51.06-59.98) for chlorpyrifos and 3250 μg/L (95% CI 2770-3810) for difenoconazole. Regarding the biomarkers, a significant inhibition of brain and muscle cholinesterase activity was recorded in fish exposed to 5.50 μg/L of chlorpyrifos. This activity was not affected when fish were exposed to the mixture of chlorpyrifos with difenoconazole. Significant changes in lactate dehydrogenase activity were observed in fish exposed to 325 μg/L of difenoconazole, whereas fish exposed to the mixture showed a significant increase in EROD activity in the liver. These results suggest harmful effects of chlorpyrifos insecticide at environmentally relevant concentrations. There is also evidence for an interaction of the 2 substances that affects the biotransformation metabolism at sublethal levels of exposure. Environ Toxicol Chem 2021;40:1940-1949. © 2021 SETAC.

Neurobehavioral anomalies in zebrafish after sequential exposures to DDT and chlorpyrifos in adulthood: Do multiple exposures interact?

A sequence of different classes of synthetic insecticides have been used over the past 70 years. Over this period, the widely-used organochlorines were eventually replaced by organophosphates, with dichlorodiphenyltrichloroethane (DDT) and chlorpyrifos (CPF) as the principal prototypes. Considerable research has characterized the risks of DDT and CPF individually, but little is known about the toxicology of transitioning from one class of insecticides to another, as has been commonplace for agricultural and pest control workers. This study used adult zebrafish to investigate neurobehavioral toxicity following 5-week chronic exposure to either DDT or CPF, to or their sequential exposure (DDT for 5 weeks followed by CPF for 5 weeks). At the end of the exposure period, a subset of fish were analyzed for brain cholinesterase activity. Behavioral effects were initially assessed one week following the end of the CPF exposure and again at 14 months of age using a behavioral test battery covering sensorimotor responses, anxiety-like functions, predator avoidance and social attraction. Adult insecticide exposures, individually or sequentially, were found to modulate multiple behavioral features, including startle responsivity, social approach, predator avoidance, locomotor activity and novel location recognition and avoidance. Locomotor activity and startle responsivity were each impacted to a greater degree by the sequential exposures than by individual compounds, with the latter being pronounced at the early (1-week post exposure) time point, but not 3–4 months later in aging. Social approach responses were similarly impaired by the sequential exposure as by CPF-alone at the aging time point. Fleeing responses in the predator test showed flee-enhancing effects of both compounds individually versus controls, and no additive impact of the two following sequential exposure. Each compound was also associated with changes in recognition or avoidance patterns in a novel place recognition task in late adulthood, but sequential exposures did not enhance these phenotypes. The potential for chemical x chemical interactions did not appear related to changes in CPF metabolism to the active oxon, as prior DDT exposure did not affect the cholinesterase inhibition resulting from CPF. This study shows that the effects of chronic adult insecticide exposures may be relevant to behavioral health initially and much later in life, and that the effects of sequential exposures may be unpredictable based on their constituent exposures.

&lt;strong&gt;&lt;span lang="EN-GB"&gt;Protective role of &lt;em&gt;Ipomoea aquatica&lt;/em&gt; Forsk. crude extract on rat tissues in the presence of acephate and carbofuran by histopathology and cytometric determination&lt;/span&gt;&lt;/strong&gt;

Ipomoea aquatica Forsk., commonly called water spinach ( ‘kalmi’ in Bengali) is an underexploited local green leafy vegetable having enormous scope as a cheap antioxidant source. The study explores the ameliorative effect of aqueous I. aquatica extract (IAE) in acephate and carbofuran treated Wistar male rats. Aqueous IAE (@ 20 mg/kg body wt.), administered to rats treated with organophosphate acephate (@ 30 mg/kg body wt.) and carbamate carbofuran (@ 0.1 mg /kg body wt.), attenuated the cholinesterase activity in brain, liver and cellular blood and reformed the histological perturbations in the brain cortex as well as the kidney anomalies, to a good extent. The IAE also upregulated the NF-E2-related factor-2 (Nrf-2) and MnSOD gene expression against pesticide toxicity. Hence, results of the present study intervenes into a new approach of justifying the deleterious side effects of pesticides that are commonly used, and how green leafy vegetables can help ameliorate those harmful effects.

Non-linear model analysis of the relationship between cholinesterase activity in rats exposed to 2, 2-dichlorovinyl dimethylphosphate (dichlorvos) and its metabolite concentrations in urine

Urinary dialkylphosphates (DAPs) are measured to assess exposure to organophosphorus pesticides (OPs), but they are common metabolites of OPs and not specific indices for individual agents. Biomonitoring (BM) of urinary DAPs has been widely adopted as an assessment of individual exposure in general environments, however, guidance values for DAPs based on health effects have yet to be established. The present study aimed to clarify the relationship between the amount of urinary dimethylphosphate (DMP), a metabolite of dichlorvos (DDVP), and the inhibition of cholinesterase (ChE) activity in rats exposed to DDVP. The relationship was analyzed using a nonlinear model analysis, and the excretion level of urinary DMP equivalent to ChE 20 % inhibition (EL20) and the lower limit of the 95 % confidence interval of EL20 (ELL20) were estimated. EL20 and ELL20 (mg/24 h urine) of brain, erythrocyte, and plasma ChE activities after 10-day administration of DDVP were 0.21 and 0.15, 0.11 and 0.06, and 0.23 and 0.09, respectively. Extrapolating ELL20 of the brain ChE to humans, the range of 24 h urinary DMP concentration according to the 20 % inhibition of cholinesterase activity was estimated to be 20.5–30.8 mg/l. In conclusion, the amount of urinary DMP as ELL20 for DDVP exposure was identified and could probably be used as a novel index for the assessment of risk from OP exposure. Further studies are needed to clarify the ELL20 s derived from OPs other than DDVP, for informing efforts to establish guidance values of urinary OP metabolites that should prevent neurotoxicity.

In vivo cholinesterase sensitivity of gilthead seabream (Sparus aurata) exposed to organophosphate compounds: Influence of biological factors

Two cholinesterases have been found in vertebrates, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). These enzymes are present in the gilthead seabream, AChE in the brain and muscle and BChE in the muscle. Cholinesterases have been used as biomarker of effect in environmental monitoring studies. However, there are few studies about the influence of biometric parameters on ChE. This paper studies the possible influence of biological factors on brain and muscle cholinesterase (ChE) in Sparus aurata. Our results show that ChE activity in brain and muscle tissues changes depending on several biological variables. ChE activity in these tissues decreased when the age (48–152 week), body length (14.15–28.95 cm) and body weight (42.73–380.74 g) of the fishes studied increased. The relationships between brain and muscle ChE activity and several biometric factors were curvilinear.On the other hand, in vivo sensitivity of cholinesterase in the gilthead seabream exposed to organophosphorus pesticides (azinphosmethyl, dimethoate and dichlorvos) was studied in order to learn about recovery from cholinesterase present (brain and muscle) after exposure to a sublethal dose. The recovery of muscle AChE was similar to cerebral AChE, while muscular BChE showed a slower recovery.

Methyl jasmonate reverses chronic stress-induced memory dysfunctions through modulation of monoaminergic neurotransmission, antioxidant defense system, and Nrf2 expressions.

Unpredictable chronic mild stress (UCMS) has been shown to cause memory loss via increased oxidative stress and deregulation of monoaminergic and cholinergic neurotransmissions. Although the benefits of methyl jasmonate (MJ), a well-known anti-stress plant hormone against chronic stress-induced psychopathologies, have been earlier reported, its effects on antioxidant defense molecules, monoaminergic transmitters, and nuclear factor erythroid 2-related factor 2 (Nrf2) immunopositive cells have not been extensively studied. The present study was designed to examine its effect on memory functions, antioxidant biomarkers, monoaminergic transmitters, and Nrf2 immunopositive cell expression in rats exposed to UCMS. Rats received an intraperitoneal injection of MJ (10, 25, and 50mg/kg) 30min before exposure to UCMS daily for 28days. Memory functionwas assessed on day 29 using a modified elevated plus maze and novel object recognition tests. The antioxidant biomarkers, level of monoamines (serotonin, noradrenaline, and dopamine), and Nrf2 immunopositive cell expression were determined in the rat brain tissues. The activity of cholinesterase and monoamine oxidase enzymes was also determined. MJ attenuated memory deficits and elevated the brain levels of monoamines in UCMS rats. UCMS-induced increase of brain cholinesterase and monoamine oxidase activities was inhibited by MJ. Also, MJ attenuated UCMS-induced decrease in antioxidant enzymes (CAT, GPx, GST, and SOD) and thiol contents in the brains of rats. UCMS-induced increase in NO level and Nrf2 immunopositive cell expression in the rat's brain was attenuated by MJ. Taken together, these findings suggest that increasing antioxidant defense molecules and monoaminergic/cholinergic neurotransmitters and decreasing the Nrf2 immunopositive cell expressions may contribute to the memory-promoting effects of MJ in rats exposed to UCMS.

Postmortem Evaluation of Reintroduced Migratory Whooping Cranes (Grus americana) in Eastern North America.

We reviewed necropsy records of 124 Whooping Cranes (Grus americana) recovered following reintroduction of 268 individuals from 2001 to 2016 in the eastern US. Causes of death were determined in 62% (77/124) of cases facilitated by active monitoring that limited decomposition and scavenging artifact. The greatest proportions of mortality were caused by predation (0.468; 95% confidence interval 0.356-0.580; 36/77), collision with power lines or vehicles (0.260; 0.162-0.358; 20/77), and gunshot (0.169; 0.085-0.253; 13/77). Six deaths were attributed to infection (0.078; 0.018-0.138; 6/77), including bacterial and fungal etiologies. Lead analysis of 50 liver samples yielded two results with elevated concentrations (3.65 and 10.97 ppm wet weight), and 10 bone samples from partial carcasses lacking suitable liver tissue resulted in one elevated result (48.82 ppm dry weight). These data indicate that underlying subclinical or clinical lead toxicosis may be a factor in up to 5% of deaths attributed to predation or impact trauma. Brain cholinesterase activity testing indicated no exposure to organophosphate or carbamate pesticides (mean±SD=17.32±2.90 µmol/min/g, 31/71). The causes of death and potential underlying factors summarized in this study constitute the first definitive mortality survey of migratory Whooping Cranes based on a high carcass recovery rate. Causes of death by infectious etiologies remained comparatively rare in this study, and occurred as single cases with no evidence of sustained transmission among reintroduced Whooping Cranes.

Difference in biochemical markers in the gibel carp (Carassius auratus gibelio) upstream and downstream of the hydropower plant

However the physiological stress in aquatic organisms associated with hydropower plants (HPP) ecosystems has been previously investigated, no studies have so far assessed it on biochemical level. Therefore this study evaluated an oxidative stress and toxicity in the gibel carp Carassius auratus gibelio associated with a small-scale HPP in the West Ukraine. A battery of liver, brain and blood markers was evaluated individuals inhabiting upstream and downstream of the dam of the small-scale Kasperivtci HPP (KHPP; an installed capacity of 7.5 MW), and from a reference site. Number of alterations were noted in fish from the KHPP impoundment facility including signs of oxidative stress (a decrease in superoxide dismutase (SOD) activity and an increase in protein carbonyls) and cytotoxicity (an increase in micronucleated erythrocytes and caspase-3 activity). No changes in DNA fragmentation in hepatocytes or brain cholinesterase activity were detected. As demonstrated by the integral stress index, fish associated with downstream of the dam revealed the greatest alterations reflected by the combined oppression of antioxidant system (SOD, catalase) and pro-oxidants (thiobarbituric acid reactive substances and oxyradicals), low concentration of metallothioneins, but high cathepsin D activity (as markers of lysosomal dysfunction and autophagy) and increased vitellogenin concentration in males (indicating an endocrine disruption). The study highlights that fish inhabiting ecosystems associated with HPP, particularly downstream of the dam, may face additional stresses with long-term effects yet to be evaluated.