3-Quinuclidinyl benzilate (agent BZ) toxicokinetics in rats.

3-Quinuclidinyl benzilate (BZ) ranks among incapacitating military warfare agents. It acts as a competitive inhibitor on muscarinic receptors leading to non-lethal mental impairment. The present study aimed to investigate toxicokinetics of BZ in rats. Moreover, BZ can be exploited to produce a pharmacological model of Alzheimer's disease; thus, this paper focuses mainly on the BZ distribution to the brain. Wistar rats were administered i.p. with BZ (2 and 10 mg/kg). The BZ concentration was determined using LC-MS/MS in plasma, urine, bile, brain, kidney and liver. The sample preparation was based on a solid phase extraction (liquids) or protein precipitation (organ homogenates). The plasma concentration peaked at 3 min (204.5 ± 55.4 and 2185.5 ± 465.4 ng/ml). The maximal concentration in the brain was reached several minutes later. Plasma elimination half-life was 67.9 ± 3.4 in the 2 mg/kg group and 96.6 ± 27.9 in the 10 mg/kg group. BZ concentrations remained steady in the brain, with slow elimination (t1/2 506.9 ± 359.5 min). Agent BZ is excreted mainly via the urine. Steady BZ concentration in the brain could explain the previously published duration of the significant impairment in passive avoidance tasks in rats after an injection of BZ.

Poisoning in domestic cats in Brazil: toxicants, clinical signs, and therapeutic approaches / [Intoxicação em gatos domésticos no Brasil: toxicantes, sinais clínicos e abordagens terapêuticas]

This study evaluated the most common toxic agents affecting domestic cats, the clinical signs of toxicity, and the therapeutic approaches for recovery. A survey on poisoning in cats was conducted among small animal veterinary practitioners from 2017 to 2018. Of the 748 completed questionnaires, 543 (72.6%) were evaluated. Pesticides and household cleaning supplies were the most common causes of poisoning in cats. The toxicant groups included pesticides and household cleaning supplies (organophosphates), human drugs (acetaminophen), plants/plant derivatives (lily), and veterinary drugs (tramadol). The major clinical signs for these four groups of toxicants were (1) acetaminophen poisoning, which caused oxidative erythrocyte damage; (2) muscarinic and nicotinic cholinergic syndrome, which resulted from organophosphate poisoning; (3) acute kidney injury, which resulted from intoxication of lily; and (4) serotonin syndrome, which resulted from tramadol toxicosis. Interventions for treating poisoning in cats were based on the clinical presentation of animals. In the present study, the significant toxins identified to be dangerous for cats were characterized using the obtained data in Brazil as well as the main associated clinical signs and therapy recommended by veterinarians.(AU)

Objetiva-se com este trabalho caracterizar os principais toxicantes para gatos domésticos, bem como os prevalentes sinais clínicos e a terapêutica associada. Uma pesquisa sobre envenenamento em gatos foi realizada entre médicos veterinários no período de 2017 a 2018. Dos 748 questionários preenchidos, 543 (72,6%) foram avaliados. Pesticidas e domissanitários foram os principais causadores de intoxicação em gatos. Entre os grupos tóxicos, destacaram-se, na categoria pesticidas e domissanitários (organofosforados), medicamentos humanos (acetaminofeno), plantas e derivados de planta (lírio) e medicamentos veterinários (tramadol). Os principais sinais clínicos para os quatro grupos de substâncias tóxicas foram: (1) intoxicação por acetaminofeno, que causou dano eritrocitário oxidativo; (2) síndrome colinérgica muscarínica e nicotínica, resultante do envenenamento por organofosforado; (3) lesão renal aguda, causada pela intoxicação por lírio; e (4) síndrome serotoninérgica, resultante da exposição ao tramadol. As intervenções realizadas para o tratamento dos envenenamentos foram justificáveis mediante a apresentação clínica dos animais. Por meio dos dados obtidos, puderam-se caracterizar os principais tóxicos para gatos no Brasil, bem como os principais sinais clínicos associados e a terapêutica preconizada pelos médicos veterinários.(AU)

A randomized trial comparing physostigmine vs lorazepam for treatment of antimuscarinic (anticholinergic) toxidrome.

BACKGROUND: Toxicity from antimuscarinic agents precipitates a constellation of signs and symptoms; two of the most significant are agitation and delirium. Benzodiazepines are commonly used for treatment; physostigmine is also effective but is underutilized due to concerns for safety and short duration of action. The objective of this study was to compare lorazepam to physostigmine for the treatment of antimuscarinic delirium and agitation. METHODS: This was a blinded, randomized clinical trial in patients presenting for antimuscarinic toxidrome. Inclusion criteria were: ≥10-<18 years old, at least one central and two peripheral antimuscarinic symptoms, delirium and moderate agitation. Subjects were randomized to either (1) lorazepam bolus (0.05 mg/kg) followed by a 4-h normal saline infusion, or (2) physostigmine 0.02 mg/kg bolus followed by a 4-h physostigmine infusion (0.02 mg/kg/h). Primary outcomes were the control of delirium and agitation after bolus and during the infusion. RESULTS: Ten (53%) subjects were enrolled in the lorazepam arm, 9 (47%) in the physostigmine arm. Diphenhydramine was the most common agent ingested (16, 84%). Fewer patients receiving physostigmine had delirium after the initial bolus (44% vs 100%, p = 0.01) and at the 4th hour of infusion (22% vs 100%, p < 0.001) compared to patients who received lorazepam. There was a significant decrease in agitation scores in the physostigmine arm compared to the lorazepam arm after the initial bolus (89% vs 30%, p = 0.02), but no difference at the 4th hour of infusion (p > 0.99). There were no seizures, bradycardia, bronchorrhea, bronchospasm, intubation, or cardiac dysrhythmias. CONCLUSION: Physostigmine was superior to lorazepam in controlling antimuscarinic delirium and agitation after bolus dosing, and control of delirium after a 4-h infusion. There were no serious adverse events in either treatment arm. Physostigmine bolus and infusion should be considered in adolescent patients with significant delirium and agitation from antimuscarinic agents.

Tiotropium bromide, a long acting muscarinic receptor antagonist triggers intracellular calcium signalling in the heart.

BACKGROUND AND PURPOSE: Tiotropium bromide (TB) is a long acting muscarinic receptor antagonist used to manage chronic obstructive pulmonary disease (COPD). Recent meta-analyses suggest an increased risk of cardiovascular events with TB. Ca2+/calmodulin dependent kinase II (CaMKII) and L-type Ca2+ channels regulate Ca2+ concentrations allowing management of Ca2+ across membranes. Pathological increases in Ca2+ are initially slow and progressive, however once the cytosolic concentration rises >1-3 µM from ~100 nM, calcium overload occurs and can lead to cell death. Ipratropium bromide, a short acting muscarinic receptor antagonist has previously been found to induce Ca2+ mediated eryptosis. The aim of this study was to investigate the role of Ca2+ in Tiotropium bromide mediated cardiotoxicity. EXPERIMENTAL APPROACH: Isolated Sprague-Dawley rat hearts were perfused with TB (10-0.1 nM) ±â€¯KN-93 (400 nM) or nifedipine (1 nM). Hearts were stained to determine infarct size (%) using triphenyltetrazolium chloride (TTC), or snap frozen to determine p-CaMKII (Thr286) expression. Cardiomyocytes were isolated using a modified Langendorff perfusion and enzymatic dissociation before preparation for Fluo 3-AM staining and flow cytometric analysis. KEY RESULTS: TB increased infarct size compared to controls by 6.91-8.41%, with no effect on haemodynamic function. KN-93/nifedipine with TB showed a 5.90/7.38% decrease in infarct size compared to TB alone, the combined use of KN-93 with TB also showed a significant increase in left ventricular developed pressure whilst nifedipine with TB showed a significant decrease in coronary flow. TB showed a 42.73% increase in p-CaMKII (Thr286) versus control, and increased Ca2+ fluorescence by 30.63% in cardiomyocytes. CONCLUSIONS AND IMPLICATIONS: To our knowledge, this is the first pre-clinical study to show that Tiotropium bromide induces Ca2+ signalling via CaMKII and L-type Ca2+ channels to result in cell damage. This has significant clinical impact due to long term use of TB in COPD patients, and warrants assessment of cardiac drug safety.

Danshensu attenuates scopolamine and amyloid-ß-induced cognitive impairments through the activation of PKA-CREB signaling in mice.

Alzheimer's disease (AD) is an important chronic neurodegenerative disorder and is mainly associated with cognitive dysfunction. At present, bioactive compounds from traditional medicinal plants have received much attention for the enhancement of cognitive function. Danshensu, a phenolic acid isolated from herbal medicines, has various pharmacological activities in the central nervous system, including anxiolytic-like and neuroprotective properties. The present study aimed to investigate the ameliorating effects of danshensu on scopolamine- and amyloid-ß (Aß) protein-induced cognitive impairments in mice. Danshensu (3 and 10 mg/kg, p.o.) effectively ameliorated scopolamine-induced cognitive dysfunction in mice, as measured in passive avoidance and Y-maze tasks. In a mechanistic study, danshensu inhibited monoamine oxidase A (MAO-A) activity but not MAO-B. Additionally, danshensu treatment increased the dopamine level and the phosphorylation levels of protein kinase A (PKA) and cAMP response element binding protein (CREB), in the cortex of the brain. Furthermore, the ameliorating effect of danshensu against scopolamine-induced cognitive impairment was fully blocked by H89, a PKA inhibitor. Finally, danshensu also ameliorated Aß-induced cognitive impairments in an animal model of AD. The results revealed that danshensu treatment significantly improved scopolamine and Aß-induced cognitive impairments in mice by facilitation of dopamine signaling cascade such as PKA and CREB due to MAO-A inhibition. Thus, danshensu could be used as a promising therapeutic agent for preventing and treating AD.

A New Ophthalmic Pharmaceutical Formulation, Topical Sulglycotide, Enhances the Ocular Mucin Secretion in Desiccation Stress-Mediated Dry Eye Disease.

Purpose: The aim of this study was the investigation of the effect of sulglycotide (SOS), a polysulfated glycopeptide derived from porcine duodenal mucin, for the treatment of dry eye disease. Methods: NOD.B10.H2b mice were exposed to an air draft for 10 days, and, simultaneously, scopolamine hydrobromide was injected subcutaneously. The mice were randomly divided into nine groups as follows: four kinds of SOS formulations and three kinds of commercial medicine. After 10 days of treatment, we estimated the effect of treatment on tear production, epithelium stabilization, mucin secretion, and inflammation. Results: The desiccation stress significantly decreased tear production and corneal epithelium stabilization, as well as markedly decreased the numbers of goblet cells and mucin-stained cells in conjunctiva. However, the topical 4% SOS eye drops markedly increased tear production and corneal stabilization, which recovered to baseline levels. In addition, topical 4% SOS significantly induced an increase in the numbers of goblet cells and the expression of membrane-associated mucins including MUC1, MUC4, and MUC16, as well as the gel-forming mucin, MUC5AC. Furthermore, SOS formulations provided anti-inflammatory improvement in a dose-dependent manner. Conclusions: In summary, we suggest that a new ophthalmic pharmaceutical formulation, topical sulglycotide, enhances the ocular mucin secretion in dry eye disease and can be used as a new ophthalmic pharmaceutical material to treat dry eye disease.

Understanding Central Nervous System Effects of Deliriant Hallucinogenic Drugs through Experimental Animal Models.

Hallucinogenic drugs potently alter human behavior and have a millennia-long history of use for medicinal and religious purposes. Interest is rapidly growing in their potential as CNS modulators and therapeutic agents for brain conditions. Antimuscarinic cholinergic drugs, such as atropine and scopolamine, induce characteristic hyperactivity and dream-like hallucinations and form a separate group of hallucinogens known as "deliriants". Although atropine and scopolamine are relatively well-studied drugs in cholinergic physiology, deliriants represent the least-studied class of hallucinogens in terms of their behavioral and neurological phenotypes. As such, novel approaches and new model organisms are needed to investigate the CNS effects of these compounds. Here, we comprehensively evaluate the preclinical effects of deliriant hallucinogens in various animal models, their mechanisms of action, and potential interplay with other signaling pathways. We also parallel experimental and clinical findings on deliriant agents and outline future directions of translational research in this field.

Datura and Brugmansia plants related antimuscarinic toxicity: an analysis of poisoning cases reported to the Taiwan poison control center.

INTRODUCTION: Datura and Brugmansia plants, especially Datura species, have been used for their hallucinogenic effects in the United States and Europe; whereas Datura plants have been used as a traditional medicine in many Asian countries. This study was conducted to better understand the pattern and outcome of Datura/Brugmansia plant related poisoning in Taiwan. METHODS: This is a retrospective case series study of all cases with Datura/Brugmansia exposure reported to the Taiwan Poison Control Center between 1986 and 2015. Data for patients with relevant poisoning were reviewed and abstracted. Logistic regression analysis was used to identify potential predictors of the severity of poisoning; bivariate analysis was employed to assess the effectiveness of physostigmine in the treatment of Datura/Brugmansia poisoning. RESULTS: A total of 203 cases involving 114 Datura exposures and 89 Brugmansia suaveolens exposures were eligible for analysis. Using Datura/Brugmansia for a medicinal purpose by the patients without consulting Chinese medicine practitioners was the most common reason of poisoning (81.2%); whereas only 2% of the patients were poisoned after medicinal use associated with the prescription from Chinese medicine practitioners. None of the 203 patients had used Datura/Brugmansia plant for recreational purpose. Most frequently observed clinical effect was mydriasis (53.2%), followed by confusion (40%), tachycardia (35.5%), dry mouth (35.5%), dizziness (34%), dry skin (32.5%), and delirium (31%). Seventy-three cases (36%) had severe effects; none of them died. Misidentification of the plants and ingestion of plant parts other than flowers were positively associated with the severity of poisoning. Forty patients (19.7%) received physostigmine therapy and patients receiving physostigmine had an earlier resolution of central nervous system toxicity than those who did not. CONCLUSIONS: Medicinal use without consulting Chinese medicine practitioners is the main reason for Datura/Brugmansia poisoning in Taiwan. Consumption of parts other than flowers and misidentification of the plants predicted the severity of poisoning in this study. Patients who received physostigmine appear to have earlier improvement in the central nervous system effects. No adverse events were reported from physostigmine administration.

Vitamin E can compensate the density of M1 receptors in the hippocampus of scopolamine-treated rats.

M1 muscarinic receptor plays a fundamental role in memory and is closely associated with Alzheimer's disease (AD); it has long been assumed as a therapeutic goal. By activating of the cholinergic receptor vitamin E helps with memory retention. But effects of vitamin E on density of M1 muscarinic receptor-immunoreactive (ir) neurons remain poorly understood. The present research aimed to examine the chronic administration effect of vitamin E against scopolamine-induced memory loss and the number of M1 muscarinic receptor-ir neurons of the hippocampus in male rats. Randomly, 42 adult male Wistar rats were divided to six groups: control, Sham-saline: receiving scopolamine + saline, Sham-sesame oil: receiving scopolamine + sesame oil and three experimental groups: receiving scopolamine + vitamin E with different doses (25, 50, and 100 mg/kg/day, i.p.) for 14 days. The passive avoidance task was used for the memory test. Twenty-four hours after behavioral tests, rats' brains were taken and fixed, and after tissue processing, sections were stained using the immunohistochemical technique for M1 muscarinic receptor-ir neurons and cresyl violet for neurons. The injection of scopolamine to rats caused memory impairment and vitamin E treatment could ameliorate it. In the scopolamine-treated groups, the number of CA1 and CA3 pyramidal and dentate gyrus (DG) granular neurons was decreased significantly as compared to the control group. Vitamin E treatment significantly increased neuron numbers in the CA1 and CA3 areas of the hippocampus and DG area. Treatment with vitamin E for 14 days could compensate the loss of M1 muscarinic receptor-immunoreactive neuron numbers induced by scopolamine in the hippocampus. The most effective vitamin E dose was 50 mg/kg/day in this study. In conclusion, vitamin E can compensate the neuronal loss in the hippocampal formation and also it can raise the density of M1 receptor-ir muscarinic neurons after an injection of scopolamine.

Virtual Thorough QT (TQT) Trial-Extrapolation of In Vitro Cardiac Safety Data to In Vivo Situation Using Multi-Scale Physiologically Based Ventricular Cell-wall Model Exemplified with Tolterodine and Fesoterodine.

QT interval prolongation typically assessed with dedicated clinical trials called thorough QT/QTc (TQT) studies is used as surrogate to identify the proarrhythmic risk of drugs albeit with criticism in terms of cost-effectiveness in establishing the actual risk of torsade de pointes (TdP). Quantitative systems toxicology and safety (QSTS) models have potential to quantitatively translate the in vitro cardiac safety data to clinical level including simulation of TQT trials. Virtual TQT simulations have been exemplified with use of two related drugs tolterodine and fesoterodine. The impact of bio-relevant concentration in plasma versus estimated heart tissue exposure on predictions was also assessed. Tolterodine and its therapeutically equipotent metabolite formed via CYP2D6 pathway, 5-HMT, inhibit multiple cardiac ion currents (IKr, INa, ICaL). The QSTS model was able to accurately simulate the QT prolongation at therapeutic and supra-therapeutic dose levels of tolterodine well within 95% confidence interval limits of observed data. The model was able to predict the QT prolongation difference between CYP2D6 extensive and poor metaboliser subject groups at both dose levels thus confirming the ability of the model to account for electrophysiologically active metabolite. The QSTS model was able to simulate the negligible QT prolongation observed with fesoterodine establishing that the 5-HMT does not prolong QT interval even though it is a blocker of hERG channel. With examples of TOL and FESO, we demonstrated the utility of the QSTS approaches to simulate virtual TQT trials, which in turn could complement and reduce the clinical studies or help optimise clinical trial designs.

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

CONTEXT: Scopolamine, a muscarinic receptor antagonist, causes memory loss that resembles Alzheimer's disease (AD). Echium amoenum L. (Boraginaceae) is a famous medicinal plant of Iran that is traditionally used as a sedative and mood enhancer. OBJECTIVE: This study evaluates the effect of hydroalcoholic extract of E. amoenum flowers on scopolamine-induced memory impairment in rats. MATERIALS AND METHODS: Fifty male Wistar rats were randomly divided into five groups. Control group received normal saline, model group received scopolamine (0.7 mg/kg, IP, daily for 21 days), and test groups received E. amoenum extract (50, 75, and 100 mg/kg, IP, daily for 21 days) 30 min before each scopolamine injection. The elevated plus maze (EPM), shuttle box, novel object and rotarod tests were performed after treatment. Brain levels of malondialdehyde (MDA) and total antioxidant capacity (TCA) were also determined. RESULTS: Scopolamine-treated rats spent more time exploring the novel object compared to the control, and E. amoenum extract at all three doses significantly decreased the time spent exploring the novel object (p < 0.05). E. amoenum extract (75 and 100 mg/kg) significantly elongated the secondary latency in rats receiving scopolamine in the shuttle box test (p < 0.05). In addition, treatment with 75 and 100 mg/kg doses of E. amoenum extract significantly ameliorated scopolamine-induced motor in coordination in rotarod test (p < 0.05). It also significantly increased the time spent in the open arms and reduced the time spent in the closed arms of EPM (p < 0.05). Treatment of scopolamine-exposed rats with E. amoenum extract significantly increased TCA and reduced MDA level of brain (p < 0.05). DISCUSSION AND CONCLUSIONS: E. amoenum extract shows protective effect against scopolamine-induced impairment and is suggested to be tested in clinical trials to evaluate the efficacy on AD.

Lithium prevents scopolamine-induced memory impairment in zebrafish.

We examined whether lithium carbonate (Li2CO3, 100mg/L) is able to prevent memory impairment induced by scopolamine. Moreover, we evaluated the effects of lithium on anxiety-like behavior and acetylcholinesterase activity in adult zebrafish. We demonstrated that lithium prevents the memory impairment induced by scopolamine, decreases exploration and increases the activity of acetylcholinesterase in zebrafish. Collectively, this contributes to a better understanding of the pharmacology of lithium, its interaction with cholinergic neurotransmission, and its possible application to therapeutic treatments aimed at improving cognition.

The expression of G protein-coupled receptor kinase 5 and its interaction with dendritic marker microtubule-associated protein-2 after status epilepticus.

OBJECTIVE: Acute seizures induced dendritic formation and synaptogenesis promotes aberrant circuitry development and further aggravates underlying conditions towards chronic epilepsy. The G protein-coupled receptor kinase-5 (GRK5) served as a key modulator in neurogenesis and the establishment of functional neuronal circuitry. This included dendritic development, as its dysfunction could cause different central nervous system disorders, including Alzheimer's disease. However, the involvement of GRK5 in the progression of epilepsy remains unclear. The purpose of this study is to investigate the involvement of GRK5 in epilepsy, as well as its potential correlation with dendritic formation after status epilepticus. METHODS: 120 rats were divided into control and model groups. The rats in the model group were injected intraperitoneally with lithium chloride-pilocarpine hydrochloride to establish the rat model of status epilepticus (SE). The brain and hippocampus were collected at 1, 3, 7, 14 and 28days post SE induction. The expression and distribution of GRK5 and the dendritic marker microtubule-associated protein-2 (MAP-2) were detected in the hippocampus via western blot or immunohistochemistry. The co-localization of GRK5 with MAP-2 was examined via laser confocal double immunofluorescence staining. The interactions between GRK5 and MAP-2 during epileptogenesis were evaluated via immunoprecipitation. RESULTS: GRK5 was distributed in all areas of the hippocampus. Its expression was significantly up-regulated in the hippocampal CA1, DG, and H areas at 7d and 14d after SE. After 14d it began to reduce. and then reduced. MAP-2 primarily existed in the neuronal dendrites of the hippocampal subregion. Its expression was enhanced at 3d. It reached its maximum level at 14d after SE, where it then began to fall. The confocal microscope analysis revealed that GRK5 was co-located well within MAP-2 positive cells. The interaction between GRK5 and MAP-2 became enhanced at 7d and 14d after SE. CONCLUSIONS: GRK5 was involved in the development of epilepsy. It was associated with dendritic formation in epilepsy. This study provides a new perspective for elucidating the epilepsy pathogenesis. The concrete mechanisms of the GRK5 within epileptogenesis require further research.

Antimuscarinic-induced convulsions in fasted mice after food intake: No evidence of spontaneous seizures, behavioral changes or neuronal damage.

Prolonged or repeated seizures have been shown to cause spontaneous recurrent seizures, increased anxiety­related behavior, locomotor hyperactivity, impaired functions of learning and memory, and neuronal damage in the hippocampus and other brain regions in animals. Mice and rats treated with antimuscarinic drugs after fasting for two days or less develop convulsions after being allowed to eat ad libitum. To address whether such behavioral and neuroanatomic changes occur following these convulsions, mice treated i.p. with saline (control) or 2.4 mg/kg atropine and given food after 24 h of fasting were grouped according to seizure scores for behavioral and histological analysis. Following convulsions, the occurrence of spontaneous recurrent seizures was observed for 30 days. Motor activity and grooming behavior were assessed in the open field, and memory was assessed using the novel object recognition test 4 and 7 days after onset of convulsions, respectively. Animals allocated for the histological analysis were decapitated 7 days after onset of convulsions and hippocampal slices were evaluated for the percentage of degenerating neurons stained with Fluoro­Jade C. Spontaneous recurrent seizures, locomotor alterations, anxiety­related behavior, memory impairment, and neuronal loss in the granular layer of the dentate gyrus were not detected in the animals with seizure score 1-2 or 3-5. These results are in accordance with those related to the absence of behavioral changes, cognitive deficits, and hippocampal neuronal damage after single brief seizures in animals and patients with epilepsy.

Lactucopicrin ameliorates oxidative stress mediated by scopolamine-induced neurotoxicity through activation of the NRF2 pathway.

Cholinergic activity plays a vital role in cognitive function, and is reduced in individuals with neurodegenerative diseases. Scopolamine, a muscarinic cholinergic antagonist, has been employed in many studies to understand, identify, and characterize therapeutic targets for Alzheimer's disease (AD). Scopolamine-induced dementia is associated with impairments in memory and cognitive function, as seen in patients with AD. The current study aimed to investigate the molecular mechanisms underlying scopolamine-induced cholinergic neuronal dysfunction and the neuroprotective effect of lactucopicrin, an inhibitor of acetylcholine esterase (AChE). We investigated apoptotic cell death, caspase activation, generation of reactive oxygen species (ROS), mitochondrial dysfunction, and the expression levels of anti- and pro-apoptotic proteins in scopolamine-treated C6 cells. We also analyzed the expression levels of antioxidant enzymes and nuclear factor (erythroid-derived 2)-like 2 (NRF2) in C6 cells and neurite outgrowth in N2a neuroblastoma cells. Our results revealed that 1 h scopolamine pre-treatment induced cytotoxicity by increasing apoptotic cell death via oxidative stress-mediated caspase 3 activation and mitochondrial dysfunction. Scopolamine also downregulated the expression the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase, and the transcription factor NRF2. Lactucopicrin treatment protected C6 cells from scopolamine-induced toxicity by reversing the effects of scopolamine on those markers of toxicity. In addition, scopolamine attenuated the secretion of neurotrophic nerve growth factor (NGF) in C6 cells and neurite outgrowth in N2a cells. As expected, lactucopicrin treatment enhanced NGF secretion and neurite outgrowth. Our study is the first to show that lactucopicrin, a potential neuroprotective agent, ameliorates scopolamine-induced cholinergic dysfunction via NRF2 activation and subsequent expression of antioxidant enzymes.

Effects of Chronic Scopolamine Treatment on Cognitive Impairments and Myelin Basic Protein Expression in the Mouse Hippocampus.

Myelin plays an important role in learning and memory, and degradation of myelin is a key feature in the pathogenesis of neurological disorders involving cognitive dysfunction. Myelin basic protein (MBP) is one of the most abundant structural proteins in myelin and is essential for myelin formation and compaction. In this study, we first examined changes in the distribution of MBP-immunoreactive myelinated fibers and MBP levels according to hippocampal subregion in mice following chronic systemic treatment with 1 mg/kg scopolamine (SCO) for 4 weeks. We found that SCO-induced cognitive impairments, as assayed by the water maze and passive avoidance tests, were significantly reduced 1 week after SCO treatment and the impairments were maintained without any hippocampal neuronal loss. MBP-immunoreactive myelinated fibers were easily detected in the stratum radiatum and lacunosum-moleculare of the hippocampus proper (CA1-3 region) and in the molecular and polymorphic layers of the dentate gyrus. The distribution of MBP-immunoreactive myelinated fibers was not altered 1 week after SCO treatment. However, the density of MBP-immunoreactive myelinated fibers was significantly decreased 2 weeks after SCO treatment; thereafter, the density gradually, though not significantly, decreased with time. In addition, the changing pattern of MBP levels in the hippocampus following SCO treatment corresponded to immunohistochemical changes. In brief, this study shows that chronic systemic treatment with SCO induced significant degradation of MBP in the hippocampus without neuronal loss at least 2 weeks after SCO treatment, although cognitive impairments occurred 1 week after SCO treatment.

[The distribution of tropicamide in the body of warm-blooded animals after its intragastric administration].

The objective of the present study was to elucidate the peculiar features of the distribution of N-ethyl-3-hydroxy-2-phenyl-N-(piridin-4-yl-methyl)propanamide (tropicamide) in the body of warm-blooded animals (rats) after its intragastric administration. The following methods were employed in the study: TLC, chromogenic reactions, electronic spectrophotometry, and GC-MS. The results of the quantitative analysis of N-ethyl-3-hydroxy-2-phenyl-N-(piridin-4-yl-methyl)propanamide in different organs of warm-blooded animals (rats) were compared within 20 minutes, 2.5 and 6 hours after its single intragastric administration at a dose equivalent to 1.5 LD50 of the toxic substance. It was shown that at all time intervals the maximum amount of tropicamide was present in the tissues of the stomach. Small intestines, their contents, brain, lungs, and spleen.

Neuroprotective Potential of Novel Multi-Targeted Isoalloxazine Derivatives in Rodent Models of Alzheimer's Disease Through Activation of Canonical Wnt/ß-Catenin Signalling Pathway.

Previous reports suggest that Alzheimer's disease is protected by cholinesterase inhibitors. We synthesized some isoalloxazine derivatives and evaluated them using in vitro cholinesterase inhibition assay. Two of the compounds (7m and 7q) were figured out as potent cholinesterase inhibitors. They further showed anti-Aß aggregatory activity in the in vitro assay. The current study deals with the evaluation of neuroprotective potentials of the potent compounds (7m and 7q) using different in vitro and in vivo experiments. The compounds were first assessed for their tendency to cross blood-brain barrier using in vitro permeation assay. They were evaluated using scopolamine-induced amnesic mice model. Additionally, ROS scavenging and anti-apoptotic properties of 7m and 7q were established against Aß1-42-induced toxicity in rat hippocampal neuronal cells. 7m and 7q were also evaluated using Aß1-42-induced Alzheimer's rat model. Lastly, their involvement in Wnt/ß-catenin pathway was also demonstrated. The results indicated good CNS penetration for 7m and 7q. The neuroprotective effects of 7m and 7q were evidenced by improved cognitive ability in both scopolamine and Aß1-42-induced Alzheimer's-like condition in rodents. The in vivo results also confirmed their anti-cholinesterase and anti-oxidant potential. Immunoblot results showed that treatment with 7m and 7q decreased Aß1-42, p-tau, cleaved caspase-3, and cleaved PARP levels in Aß1-42-induced Alzheimer's rat brain. Additionally, immunoblot results demonstrated that 7m and 7q activated the Wnt/ß-catenin pathway as evidenced by increased p-GSK-3, ß-catenin, and neuroD1 levels in Aß1-42-induced Alzheimer's rat brain. These findings have shown that isoalloxazine derivatives (7m and 7q) could be the potential leads for developing effective drugs for the treatment of AD.

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

PURPOSE: Present study was undertaken to evaluate the antiamnesic effect of Sesamum indicum (S. indicum) seeds (standardized for sesamin, a lignan, content) in scopolamine, a muscarinic antagonist intoxicated mice. METHODS: Male Swiss albino mice (18-22 g bw) were pretreated with methanolic extract of sesame seeds (MSSE) (100 and 200 mg/kg/day, p.o) for a period of 14 days. Scopolamine (0.3 mg/kg, i.p.) was injected on day 14, 45 ± 10 min after MSSE administration. Antiamnesic effect of MSSE was evaluated using step-down latency (SDL) on passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. To unravel the mechanism of action, we examined the effects of MSSE on the genes such as acetyl cholinesterase (AChE), muscarinic receptor M1 subtype (mAChRM1 ), and brain derived neurotrophic factor (BDNF) expression within hippocampus of experimental mice. Further, its effects on bax and bcl-2 were also evaluated. Histopathological examination of hippocampal CA1 region was performed using cresyl violet staining. RESULTS: MSSE treatment produced a significant and dose dependent increase in step down latency in passive avoidance test and decrease in transfer latency in elevated plus maze in scopolamine intoxicated injected mice. MSSE down-regulated AChE and mAChRM1 and up-regulated BDNF mRNA expression. Further, it significantly down-regulated the bax and caspase 3 and up-regulated bcl-2 expression in scopolamine intoxicated mice brains. Mice treated with MSSE showed increased neuronal counts in hippocampal CA1 region when compared with scopolamine-vehicle treated mice. CONCLUSION: Sesame seeds have the ability to interact with cholinergic components involved in memory function/restoration and also an interesting candidate to be considered for future cognitive research. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1955-1963, 2016.