The selective norepinephrine reuptake inhibitor atomoxetine counteracts behavioral impairments in trimethyltin-intoxicated rats

Impact of glyphosate-based herbicide exposure through maternal milk on offspring's antioxidant status, neurodevelopment, and behavior

Glyphosate-based Herbicide (GBH) is a widely used pesticide that functions as a broad-spectrum, non-selective herbicide. Despite advanced research to describe the neurotoxic potential of GBH, the harmful effects on maternal behavior and neurodevelopment of offspring remain unclear. This study was conducted to highlight the effects of GBH on the antioxidant system, anxiety traits, social interaction, and cognitive and sensorimotor functions in pups exposed to 25 or 50 mg/l daily via their mother's milk. Concerning the biochemical biomarkers, GBH administered during the early stages of development negatively affected the status of antioxidant enzymes and lipid peroxidation in the brain structures of the pups. Furthermore, our results showed a significant decrease in acetylcholinesterase (AChE) specific activity within the brains of treated pups. The results of the behavioral tests indicated that the treated offspring developed anxiety, memory, and sociability disorders, as evidenced by the Open Field, Y-maze, object recognition task, and social interaction tests. Through neurodevelopmental testing, we also showed sensorimotor impairment (righting reflex and negative geotaxis) and abnormal maternal behavior. Altogether, our study clearly demonstrates that the developing brain is sensitive to GBH.

The Effects of Peripubertal THC Exposure in Neurodevelopmental Rat Models of Psychopathology

Adolescent exposure to cannabinoids as a postnatal environmental insult may increase the risk of psychosis in subjects exposed to perinatal insult, as suggested by the two-hit hypothesis of schizophrenia. Here, we hypothesized that peripubertal Δ⁹-tetrahydrocannabinol (aTHC) may affect the impact of prenatal methylazoxymethanol acetate (MAM) or perinatal THC (pTHC) exposure in adult rats. We found that MAM and pTHC-exposed rats, when compared to the control group (CNT), were characterized by adult phenotype relevant to schizophrenia, including social withdrawal and cognitive impairment, as revealed by social interaction test and novel object recognition test, respectively. At the molecular level, we observed an increase in cannabinoid CB1 receptor (Cnr1) and/or dopamine D2/D3 receptor (Drd2, Drd3) gene expression in the prefrontal cortex of adult MAM or pTHC-exposed rats, which we attributed to changes in DNA methylation at key regulatory gene regions. Interestingly, aTHC treatment significantly impaired social behavior, but not cognitive performance in CNT groups. In pTHC rats, aTHC did not exacerbate the altered phenotype nor dopaminergic signaling, while it reversed cognitive deficit in MAM rats by modulating Drd2 and Drd3 gene expression. In conclusion, our results suggest that the effects of peripubertal THC exposure may depend on individual differences related to dopaminergic neurotransmission.

Effect of atomoxetine on ADHD-pain hypersensitization comorbidity in 6-OHDA lesioned mice

BACKGROUND

Methylphenidate and atomoxetine are used for the treatment of attention-deficit/hyperactivity disorder (ADHD). Our previous studies established the validity of the 6-hydroxydopamine (6-OHDA) mouse model of ADHD and demonstrated hypersensitivity to pain, in line with clinical reports in ADHD patients. Acute methylphenidate treatment reduces hyperactivity and increases attention, but does not affect pain behaviors in this mouse model. Whereas atomoxetine has been shown to be effective against some symptoms of ADHD, nothing is known about its possible action on comorbid pain hypersensitivity. The objectives of the present research are (1) to investigate the effects of acute and chronic treatment with atomoxetine on ADHD-like symptoms and nociceptive thresholds, and (2) to explore the catecholaminergic systems underlying these effects.

METHODS

Sham and 6-OHDA cohorts of male mice were tested for hyperactivity (open field), attention and impulsivity (5-choice serial reaction time task test), and thermal (hot plate test) and mechanical (von Frey test) thresholds after acute or repeated treatment with vehicle or atomoxetine (1, 3 or 10 mg/kg).

RESULTS

Acute administration of atomoxetine (10 mg/kg) reduced the hyperactivity and impulsivity displayed by 6-OHDA mice, without affecting attention or nociception. However, atomoxetine administered at 3 mg/kg/day for 7 days alleviated the ADHD-like core symptoms and attenuated the hyperalgesic responses. Furthermore, hyperlocomotion and anti-hyperalgesic activity were antagonized with phentolamine, propranolol, and sulpiride pre-treatments.

CONCLUSION

These findings demonstrated that when administered chronically, atomoxetine has a significant effect on ADHD-associated pain hypersensitization, likely mediated by both α- and β-adrenergic and D2/D3 dopaminergic receptors, and suggest new indications for atomoxetine that will need to be confirmed by well-designed clinical trials.

JAK2/STAT3 pathway mediates neuroprotective and pro-angiogenic treatment effects of adult human neural stem cells in middle cerebral artery occlusion stroke animal models

Mismatches between pre-clinical and clinical results of stem cell therapeutics for ischemic stroke limit their clinical applicability. To overcome these discrepancies, precise planning of pre-clinical experiments that can be translated to clinical trials and the scientific elucidation of treatment mechanisms is important. In this study, adult human neural stem cells (ahNSCs) derived from temporal lobe surgical samples were used (to avoid ethical and safety issues), and their therapeutic effects on ischemic stroke were examined using middle cerebral artery occlusion animal models. 5 × 10⁵ ahNSCs was directly injected into the lateral ventricle of contralateral brain hemispheres of immune suppressed rat stroke models at the subacute phase of stroke. Compared with the mock-treated group, ahNSCs reduced brain tissue atrophy and neurological sensorimotor and memory functional loss. Tissue analysis demonstrated that the significant therapeutic effects were mediated by the neuroprotective and pro-angiogenic activities of ahNSCs, which preserved neurons in ischemic brain areas and decreased reactive astrogliosis and microglial activation. The neuroprotective and pro-angiogenic effects of ahNSCs were validated in in vitro stroke models and were induced by paracrine factors excreted by ahNSCs. When the JAK2/STAT3 signaling pathway was inhibited by a specific inhibitor, AG490, the paracrine neuroprotective and pro-angiogenic effects of ahNSCs were reversed. This pre-clinical study that closely simulated clinical settings and provided treatment mechanisms of ahNSCs for ischemic stroke may aid the development of protocols for subsequent clinical trials of ahNSCs and the realization of clinically available stem cell therapeutics for ischemic stroke.

Early Blockade of CB1 Receptors Ameliorates Schizophrenia-like Alterations in the Neurodevelopmental MAM Model of Schizophrenia

In agreement with the neurodevelopmental hypothesis of schizophrenia, prenatal exposure of Sprague-Dawley rats to the antimitotic agent methylazoxymethanol acetate (MAM) at gestational day 17 produces long-lasting behavioral alterations such as social withdrawal and cognitive impairment in adulthood, mimicking a schizophrenia-like phenotype. These abnormalities were preceded at neonatal age both by the delayed appearance of neonatal reflexes, an index of impaired brain maturation, and by higher 2-arachidonoylglycerol (2-AG) brain levels. Schizophrenia-like deficits were reversed by early treatment [from postnatal day (PND) 2 to PND 8] with the CB1 antagonist/inverse agonist AM251 (0.5 mg/kg/day). By contrast, early CB1 blockade affected the behavioral performance of control rats which was paralleled by enhanced 2-AG content in the prefrontal cortex (PFC). These results suggest that prenatal MAM insult leads to premorbid anomalies at neonatal age via altered tone of the endocannabinoid system, which may be considered as an early marker preceding the development of schizophrenia-like alterations in adulthood.

Prenatal Trimethyltin Exposure Induces Long-Term DNA Methylation Changes in the Male Mouse Hippocampus

Trimethyltin (TMT) is an irreversible neurotoxicant. Because prenatal TMT exposure has been reported to induce behavioral changes, this study was conducted to observe gender differences and epigenetic changes using a mouse model. In behavioral testing of offspring at 5 weeks of age, the total times spent in the center, corner, or border zones in the male prenatal TMT-exposed mice were less than those of control unexposed mice in the open-field test. Female TMT-exposed mice scored lower on total numbers of arm entries and percentages of alternations than controls in the Y-maze test with lower body weight. We found that only TMT-exposed males had fewer copies of mtDNA in the hippocampus and prefrontal cortex region than controls. Additional epigenetic changes, including increased 5-methyl cytosine/5-hydroxymethyl cytosine levels in the male TMT hippocampus, were observed. After methylation binding domain (MBD) sequencing, multiple signaling pathways related to metabolism and neurodevelopment, including FoxO signaling, were identified by pathway analysis for differentially methylated regions (DMRs). Increased FOXO3 and decreased ASCL1 expression were also observed in male TMT hippocampi. This study suggests that sex differences and epigenetics should be more carefully considered in prenatal toxicology studies.

Crosstalk between the transcriptional regulation of dopamine D2 and cannabinoid CB1 receptors in schizophrenia: Analyses in patients and in perinatal Δ9-tetrahydrocannabinol-exposed rats

Perinatal exposure to Δ9-tetrahydrocannabinol (THC) affects brain development and might increase the incidence of psychopathology later in life, which seems to be related to a dysregulation of endocannabinoid and/or dopaminergic systems. We here evaluated the transcriptional regulation of the genes encoding for the cannabinoid CB1 receptor (Cnr1) and the dopamine D2 receptor (Drd2) in perinatal THC-(pTHC) exposed male rats, focusing on the role of DNA methylation analyzed by pyrosequencing. Simultaneously, the molecular and behavioral abnormalities at two different time points (i.e., neonatal age and adulthood) and the potential preventive effect of peripubertal treatment with cannabidiol, a non-euphoric component of Cannabis, were assessed. The DRD2 methylation was also evaluated in a cohort of subjects with schizophrenia. We observed an increase in both Cnr1 and Drd2 mRNA levels selectively in the prefrontal cortex of adult pTHC-exposed rats with a consistent reduction in DNA methylation at the Drd2 regulatory region, paralleled by social withdrawal and cognitive impairment which were reversed by cannabidiol treatment. These adult abnormalities were preceded at neonatal age by delayed appearance of neonatal reflexes, higher Drd2 mRNA and lower 2-arachidonoylglycerol (2-AG) brain levels, which persisted till adulthood. Alterations of the epigenetic mark for DRD2 were also found in subjects with schizophrenia. Overall, reported data add further evidence to the dopamine-cannabinoid interaction in terms of DRD2 and CNR1 dysregulation which could be implicated in the pathogenesis of schizophrenia spectrum disorders, suggesting that cannabidiol treatment may normalize pTHC-induced psychopathology by modulating the altered dopaminergic activity.

Effects of Regular Exercise on Diabetes-Induced Memory Deficits and Biochemical Parameters in Male Rats

The main objective of current work was to determine the effects of treadmill-running and swimming exercise on passive avoidance learning (PAL) and blood biochemical parameters in rats with streptozotocin (STZ)-induced diabetes. Male Wistar rats were divided into the following 6 groups (N = 6-8 per group): CON, healthy rats without exercise (N = 8); STZ, diabetic rats without exercise (N = 8); CON-SE, healthy rats subjected to swimming exercise (2 months; N = 6); STZ-SE, diabetic rats subjected to swimming exercise (2 months; N = 7); CON-TE, healthy rats subjected to treadmill exercise (2 months; N = 8); STZ-TE, diabetic rats subjected to treadmill exercise (2 months; N = 8). Diabetes was induced by a single intraperitoneal injection of 50 mg/kg STZ. Our results showed that STZ decreased the step-through latency in the retention test (STLr) and increased the time spent in the dark compartment (TDC) when compared with the CON group. However, treadmill-running and swimming exercise in STZ-treated rats increased the STLr and decreased the TDC when compared with STZ-treated rats without exercise in PAL. Blood low-density lipoprotein (LDL) and triglyceride (TG) levels in the STZ group were significantly higher than those in the CON group, whereas plasma total antioxidant capacity (TAC) and levels of catalase (CAT) and glutathione peroxidase (GPx) were lower in the STZ group compared with the CON group. The levels of LDL and TG decreased and the levels of TAC, CAT, and GPx increased in the exercise groups in comparison with the STZ group. The present results indicate that regular exercise enhances learning and memory in diabetic rats and that these effects may occur through activation of the antioxidant system.

Association between 10 urinary heavy metal exposure and attention deficit hyperactivity disorder for children

Attention deficit hyperactivity disorder (ADHD) is associated with heavy metal exposure during adolescent development. However, the direct clinical evidence is limited. To investigate the possible association between environmental heavy metal exposure and ADHD, a case-control study was conducted with children aged 6-14 years in Guangzhou, China. Results showed that median concentrations of chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), tin (Sn), barium (Ba), and lead (Pb) in the urine of the case group were significantly higher than those of the control group. Children with ADHD had significantly higher levels of 8-OHdG and MDA compared with those from the control group. In addition, correlations between urinary Co, Ni, Cu, Mo, and Sn were significantly correlated with 8-OHdG and MDA concentrations in urine. After the case and control groups were combined together and the first quartile was used as the reference category, odds ratios (ORs) of ADHD for children increased significantly with the quartile increasing of urinary Co, Cu, and Sn. Our study provides a clinical evidence that Co, Cu, and Sn exposure, particularly Sn exposure, may be an environmental risk of the incurrence of ADHD for children. Furthermore, Co, Ni, Cu, Mo, and Sn exposures were significantly correlated with DNA and lipid damage.

Exposure to glyphosate during pregnancy induces neurobehavioral alterations and downregulation of Wnt5a-CaMKII pathway

Glyphosate-based formulations are the most popular herbicide used around the world. These herbicides are widely applied in agriculture to control weeds on genetically modified crops. Although there is much evidence showing that glyphosate-based herbicides induce toxic effect on reproductive and hepatic systems, and also cause oxidative damage on cells, studies from recent years revealed that the nervous system may represent a key target for their toxicity. In the present work, we evaluated the effect of glyphosate (without adjuvants) in neonate rats after gestational exposure. Particularly, we examined whether glyphosate during gestation affected the nervous system function at early development. Pregnant Wistar rats were treated with 24 or 35 mg/kg of pure glyphosate every 48 h and neurobehavioral studies were performed. Our results indicated that gestational exposure to glyphosate induced changes in reflexes development, motor activity and cognitive function, in a dose-dependent manner. To go further, we evaluated whether prenatal exposure to glyphosate affected the Ca+2-mediated Wnt non-canonical signaling pathway. Results indicated that embryos exposed to glyphosate showed an inhibition of Wnt5a-CaMKII signaling pathway, an essential cascade controlling the formation and integration of neural circuits. Taken together, these findings suggest that gestational exposure to glyphosate leads to a downregulation of Wnt/Ca+2 pathway that could induce a developmental neurotoxicity evidenced by deficits at behavioral and cognitive levels in rat pups.

Autophagy in trimethyltin-induced neurodegeneration

Autophagy is a degradative process playing an important role in removing misfolded or aggregated proteins, clearing damaged organelles, such as mitochondria and endoplasmic reticulum, as well as eliminating intracellular pathogens. The autophagic process is important for balancing sources of energy at critical developmental stages and in response to nutrient stress. Recently, autophagy has been involved in the pathophysiology of neurodegenerative diseases although its beneficial (pro-survival) or detrimental (pro-death) role remains controversial. In the present review, we discuss the role of autophagy following intoxication with trimethyltin (TMT), an organotin compound that induces severe hippocampal neurodegeneration associated with astrocyte and microglia activation. TMT is considered a useful tool to study the molecular mechanisms occurring in human neurodegenerative diseases such as Alzheimer's disease and temporal lobe epilepsy. This is also relevant in the field of environmental safety, since organotin compounds are used as heat stabilizers in polyvinyl chloride polymers, industrial and agricultural biocides, and as industrial chemical catalysts.

The effects of aqueous extract of Origanum vulgare on learning and memory in male rats

Introduction: The effectiveness of antioxidants on learning and memory improvement has been shown, previously. Due to the high level of antioxidants, available in Origanum vulgare, the present experiment aimed to examine the effect of aqueous extract of O. vulgare on passive avoidance learning (PAL) in male Wistar rats. Methods: This study was performed on 30 male Wistar rats weighing 250 to 290 g. The rats were randomly assigned into five groups (n=6), as follows: the control, sham (saline), and three groups treated with different doses of O. vulgare extract (150, 250, and 350 mg/kg). The saline or extract was administered via daily oral gavage for 14 days. The groups were then subjected to the passive avoidance task, and their behaviors were recorded. The rats’ locomotor activity was also measured using the open field test. Results: The number of trials to acquisition was significantly lower in the "O. vulgare (350 mg/ kg)" group than the control group. The step-through latency and the time spent in the dark compartment in the retention test, was significantly higher and lower in the "O. vulgare (250 and 350 mg/kg)" groups than the control group, respectively. No significant differences were found in the distances traveled among the experimental groups in the open field test. Conclusion: Aqueous extract of O. vulgare can enhance learning and memory. The high levels of antioxidants in O. vulgare extract may be responsible for its effectiveness in learning and memory.

Atomoxetine improves hippocampal cell proliferation but not memory in Doxorubicin-treated adult male rats

Atomoxetine (ATX) is a noradrenaline reuptake inhibitor used to treat Attention deficit hyperactive disorder (ADHD), or improve cognition in normal subjects. Cancer patients treated with systemic adjuvant chemotherapy have described experiencing deterioration in cognition. Doxorubicin (DOX, Adriamycin) is one of the anthracycline families used in chemotherapy, which has a deteriorating effect on both cognition and proliferation. The cognitive effects of ATX require inputs from the hippocampus. The aim of this study was to examine spatial memory and proliferation in the subgranular zone (SGZ) of the DG in adult Lister Hooded rats treated either alone or with a combination of Atomoxetine (30 mg kg⁻¹ day⁻¹, six i.p. doses, one injection every other day) and Doxorubicin (DOX) ( 2 mg kg⁻¹ day⁻¹, six i.p. doses, one injection every other day). Spatial memory was tested using the Novel location recognition (NLR) test, and proliferation of hippocampal cells was quantified using immunohistochemistry for the proliferative marker Ki67. Results showed that ATX treatment has improved the NLR task and increased cell proliferation in the SGZ of the DG, compared with saline‐treated controls. Animals treated with DOX only showed deficits in NLR task, and co‐administration of ATX along with DOX did not improve their performance. DOX chemotherapy caused a significant reduction in the number of proliferating cells in the SGZ of the DG compared with saline‐treated controls. This reduction was reversed by co‐administration of ATX. The above findings suggest that DOX can negatively affect both cell proliferation and memory and ATX co‐administration improves proliferation, but not memory in the adult male rat hippocampus.

Systematic review and meta-analysis of the behavioral effects of methylphenidate in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder

The spontaneously hypertensive rats (SHR) are the most widely used model for ADHD. While face and construct validity are consolidated, questions remain about the predictive validity of the SHR model. We aim at summarizing the evidence for the predictive validity of SHR by evaluating its ability to respond to methylphenidate (MPH), the most well documented treatment for ADHD. A systematic review was carried out to identify studies evaluating MPH effects on SHR behavior. Studies (n=36) were grouped into locomotion, attention, impulsivity or memory, and a meta-analysis was performed. Meta-regression, sensitivity, heterogeneity, and publication bias analyses were also conducted. MPH increased attentional and mnemonic performances in the SHR model and decreased impulsivity in a dose-dependent manner. However, MPH did not reduce hyperactivity in low and medium doses, while increased locomotor activity in high doses. Thus, since the paradoxical effect of stimulant in reducing hyperactivity was not observed in the SHR model, our study does not fully support the predictive validity of SHR, questioning their validity as an animal model for ADHD.

Effect of Achillea millefolium aqueous extract on memory deficit and anxiety caused by stroke in ovariectomized rats

Introduction: Some studies indicated that the decrease of estrogen level in menopausal woman results in increasing the risk of stroke. Although estrogen is a neuroprotective factor, high consumption of this compound may develop breast cancer and endometriosis. The present study investigated the effect of Achilles millefolium extract, containing estrogenlike compounds, on memory impairment and anxiogenic-like behaviors caused by cerebral ischemia in ovariectomized rats. Methods: Permanent middle cerebral artery ligation was performed, as a model for studying postmenopausal condition, in 48 female Wistar rats weighing 200-250 g. The aqueous extract of A. millefolium was prepared and gavaged for 4 weeks after inducing cerebral ischemia. Memory and anxiety-like behavior assessments were evaluated by step-through and elevated plus maze apparatus, respectively. Result: According to the results, cerebral ischemia in ovariectomized rats induced amnesia and anxiogenic-like behaviors which were restored by 7 mg/kg of A. millefolium aqueous extract. Furthermore, inactivation of estrogen receptors (ERs) by tamoxifen (100 µg/kg, intraperitoneally) blocked the restoration effect of A. millefolium on behaviors induced by cerebral ischemia. Conclusion: It could be concluded that, oral administration of A. millefolium extract is able to restore memory impairment and anxiogenic-like behaviors induced by ischemia via ERs in ovariectomized rat.

The Atxn7-overexpressing mice showed hyperactivity and impulsivity which were ameliorated by atomoxetine treatment: A possible animal model of the hyperactive-impulsive phenotype of ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous neurodevelopmental disorder characterized by varying levels of hyperactivity, inattention, and impulsivity. Patients with ADHD are often classified as (1) predominantly hyperactive-impulsive, (2) predominantly inattentive, and (3) combined type. There is a growing interest in developing specific animal models that would recapitulate specific clinical forms of ADHD, with the goal of developing specific therapeutic strategies. In our previous study, we have identified Ataxin-7 (Atxn7) as a hyperactivity-associated gene. Here, we generated Atxn7 overexpressing (Atxn7 OE) mice to investigate whether the increased Atxn7 expression in the brain correlates with ADHD-like behaviors. Quantitative real-time polymerase chain reaction and immunofluorescence confirmed overexpression of the Atxn7 gene and protein in the prefrontal cortex (PFC) and striatum (STR) of the Atxn7 OE mice. The Atxn7 OE mice displayed hyperactivity and impulsivity, but not inattention. Interestingly, treatment with the ADHD drug, atomoxetine (3 mg/kg, intraperitoneal), attenuated ADHD-like behaviors and reduced Atxn7 gene expression in the PFC and STR of these mice. These findings suggest that Atxn7 plays a role in the pathophysiology of ADHD, and that the Atxn7 OE mice can be used as an animal model of the hyperactive-impulsive phenotype of this disorder. Although confirmatory studies are warranted, the present study provides valuable information regarding the potential genetic underpinnings of ADHD.

Effect of ghrelin on serum metabolites in Alzheimer's disease model rats; a metabolomics studies based on 1H-NMR technique

OBJECTIVES

Alzheimer's disease (AD) is dysfunction of the central nervous system and as a neurodegenerative disease. The objective of this work is to investigate metabolic profiling in the serum of animal models of AD compared to healthy controls and then to peruse the role of ghrelin as a therapeutic approach for the AD.

MATERIALS AND METHODS

Nuclear magnetic resonance (NMR) technique was used for identification of metabolites that are differentially expressed in the serum of a rat model of the AD with or without ghrelin treatment. Using multivariate statistical analysis, models were built and indicated.

RESULTS

There were significant differences and high predictive power between AD and ghrelin-treated groups. The area under curve (AUC) of receiver operating characteristic (ROC) curve and Q2 were 0.870 and 0.759, respectively. A biomarker panel consisting of 14 metabolites was identified to discriminate the AD from the control group. Another panel of 12 serum metabolites was used to differentiate AD models from treated models.

CONCLUSION

Both panels had good agreements with clinical diagnosis. Analysis of the results displayed that ghrelin improved memory and cognitive abilities. Affected pathways by ghrelin included oxidative stress, and osteoporosis pathways and vascular risk factors.

Behavioural effects of methylphenidate in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder: a systematic review and meta-analysis protocol

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent condition related to several negative outcomes, and its pathophysiology is still poorly understood. The spontaneously hypertensive rats (SHRs) are the most commonly used animal model of ADHD. How ever, its validity, and especially its predictive validity, has been questioned. Therefore, the current protocol discloses the background, aims and methods of a systematic review and meta-analysis of studies reporting the behavioural effects of methylphenidate (MPH), the most commonly prescribed treatment for ADHD, in the SHR.

SEARCH STRATEGY

Studies will be identified through a literature search using three different electronic databases: Medline, Embase and Web of Science. There will be no language restrictions. All s tudies that administered MPH to SHR and evaluated locomotion, attention, impulsivity or memory will be included.

SCREENING AND ANNOTATION

Studies will be prescreened based on title and abstract, and a full-text review will be performed if necessary. Screening will be performed by two authors, and any disagreement will be discussed with a third author.

DATA MANAGEMENT AND REPORTING

Data extraction will be performed by two independent authors according to a standardised form. Studies will be grouped according to the behavioural outcomes reported, and a meta-analysis will be performed for each group. The influence of predefined covariates on the effects of MPH will be evaluated using meta-regression and sensitivity analyses. Data will be reported following PRISMA guidelines.

Trimethyltin-induced hippocampal neurodegeneration: A mechanism-based review

Trimethyltin (TMT), a toxic organotin compound, induces neurodegeneration selectively involving the limbic system and especially prominent in the hippocampus. Neurodegeneration-associated behavioral abnormalities, such as hyperactivity, aggression, cognitive deficits, and epileptic seizures, occur in both exposed humans and experimental animal models. Previously, TMT had been used generally in industry and agriculture, but the use of TMT has been limited because of its dangers to people. TMT has also been used to make a promising in vivo rodent model of neurodegeneration because of its region-specific characteristics. Several studies have demonstrated that TMT-treated animal models of epileptic seizures can be used as tools for researching hippocampus-specific neurotoxicity as well as the molecular mechanisms leading to hippocampal neurodegeneration. This review summarizes the in vivo and in vitro underlying mechanisms of TMT-induced hippocampal neurodegeneration (oxidative stress, inflammatory responses, and neuronal death/survival). Thus, the present review may be helpful to provide general insights into TMT-induced neurodegeneration and approaches to therapeutic interventions for neurodegenerative diseases, including temporal lobe epilepsy.

Exposure to a glyphosate-based herbicide during pregnancy and lactation induces neurobehavioral alterations in rat offspring

The impact of sub-lethal doses of herbicides on human health and the environment is a matter of controversy. Due to the fact that evidence particularly of the effects of glyphosate on the central nervous system of rat offspring by in utero exposure is scarce, the purpose of the present study was to assess the neurobehavioral effects of chronic exposure to a glyphosate-containing herbicide during pregnancy and lactation. To this end, pregnant Wistar rats were exposed through drinking water to 0.2% or 0.4% of a commercial formulation of glyphosate (corresponding to a concentration of 0.65 or 1.30g/L of glyphosate, respectively) during pregnancy and lactation and neurobehavioral alterations in offspring were analyzed. The postnatal day on which each pup acquired neonatal reflexes (righting, cliff aversion and negative geotaxis) and that on which eyes and auditory canals were fully opened were recorded for the assessment of sensorimotor development. Locomotor activity and anxiety levels were monitored via open field test and plus maze test, respectively, in 45- and 90-day-old offspring. Pups exposed to a glyphosate-based herbicide showed early onset of cliff aversion reflex and early auditory canal opening. A decrease in locomotor activity and in anxiety levels was also observed in the groups exposed to a glyphosate-containing herbicide. Findings from the present study reveal that early exposure to a glyphosate-based herbicide affects the central nervous system in rat offspring probably by altering mechanisms or neurotransmitter systems that regulate locomotor activity and anxiety.

Hydroalcoholic Extract of Ferulago angulata Improves Memory and Pain in Brain Hypoperfusion Ischemia in Rats

Background:

Objectives:

Materials and Methods:

Results:

Conclusions:

Atomoxetine reduces hyperactive/impulsive behaviours in neurokinin-1 receptor 'knockout' mice

Background

Mice with functional ablation of the neurokinin-1 receptor gene (NK1R^−/−) display behavioural abnormalities which resemble the hyperactivity, inattention and impulsivity seen in Attention Deficit Hyperactivity Disorder (ADHD). Here, we investigated whether the established ADHD treatment, atomoxetine, alleviates these abnormalities when tested in the light/dark exploration box (LDEB) and 5-Choice Serial Reaction-Time Task (5-CSRTT).

Methods

Separate cohorts of mice were tested in the 5-CSRTT and LDEB after treatment with no injection, vehicle or atomoxetine (5-CSRTT: 0.3, 3 or 10 mg/kg; LDEB: 1, 3 or 10 mg/kg).

Results

Atomoxetine reduced the hyperactivity displayed by NK1R^−/− mice in the LDEB at a dose (3 mg/kg) which did not affect the locomotor activity of wildtypes. Atomoxetine (10 mg/kg) also reduced impulsivity in NK1R^−/− mice, but not wildtypes, in the 5-CSRTT. No dose of drug affected attention in either genotype.

Conclusions

This evidence that atomoxetine reduces hyperactive/impulsive behaviours in NK1R^−/− mice consolidates the validity of using NK1R^−/− mice in research of the aetiology and treatment of ADHD.

•

We compared the behavioural response to atomoxetine in NK1R^−/− and wildtype mice.

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Atomoxetine reduced hyperactivity and impulsivity in NK1R^−/− mice but not wildtypes.

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This was not explained by changes in animals' emotional status or motor motivation.

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NK1R^−/− mice are more sensitive to atomoxetine (an ADHD treatment) than wildtypes.

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These findings consolidate the NK1R^−/− mouse model of ADHD.

The effects of atomoxetine and methylphenidate on the prepulse inhibition of the acoustic startle response in mice

Atomoxetine (ATM) and methylphenidate (MPD) have been used for the treatment of attention deficit hyperactivity disorder (ADHD). ATM is a selective norepinephrine reuptake inhibitor, whereas MPD is a psychostimulant and acts as a norepinephrine and dopamine reuptake inhibitor. In the present study, we investigated the effects of ATM (1, 3 or 10mg/kg) and MPD (5, 10 or 20mg/kg) on pharmacological mouse models of sensorimotor gating measured by prepulse inhibition (PPI) using the acoustic startle response test. MK-801, a non-competitive N-methyl-d-aspartate receptor antagonist, or apomorphine, a non-competitive dopamine receptor agonist, was used to induce PPI deficits. ATM (3 or 10mg/kg, s.c.) significantly attenuated the MK-801-, but not apomorphine-, induced PPI deficits. In contrast to ATM, MPD did not reverse the PPI deficits induced by either MK-801 or apomorphine. Immunostaining revealed that the number of c-Fos-immunopositive cells was increased in the nucleus accumbens following MK-801 treatment, and this was reversed by the administration of ATM (3mg/kg), but not MPD (10mg/kg). However, neither ATM nor MPD reversed the increased number of c-Fos-immunopositive cells in the nucleus accumbens following apomorphine treatment. These results suggest that the attenuating effect of ATM on the increased c-Fos immunoreactivity in the nucleus accumbens induced by MK-801 may be attributed to the PPI deficit-ameliorating effects of ATM and that ATM would be useful to treat sensorimotor gating-related disorders by improving the patient's attention span or cognitive function.

Effects of serotonin-norepinephrine reuptake inhibitors on locomotion and prefrontal monoamine release in spontaneously hypertensive rats

Catecholamine neurotransmission in the prefrontal cortex plays a key role in the therapeutic actions of drugs for attention-deficit/hyperactivity disorder (ADHD). Recent clinical studies show that several serotonin-norepinephrine reuptake inhibitors have potential for treating ADHD. In this study, we examined the effects of acute treatment with serotonin-norepinephrine reuptake inhibitors on locomotion and the extracellular levels of monoamines in the prefrontal cortex in spontaneously hypertensive rats (SHR), an animal model of ADHD. Adolescent male SHR exhibited greater horizontal locomotion in an open-field test than male WKY control rats. Psychostimulant methylphenidate (0.3 and 1 mg/kg), the selective norepinephrine reuptake inhibitor atomoxetine (1 and 3 mg/kg), and serotonin-norepinephrine reuptake inhibitors duloxetine (10 mg/kg), venlafaxine (10 and 30 mg/kg) and milnacipran (30 mg/kg) reduced the horizontal activity in SHR, but did not affect in WKY rats. The selective norepinephrine reuptake inhibitor reboxetine (10 mg/kg) and the tricyclic antidepressant desipramine (10 and 30 mg/kg) also reduced the horizontal activity in SHR, whereas the selective serotonin reuptake inhibitor citalopram (30 mg/kg) did not. Microdialysis studies showed that atomoxetine, methylphenidate, duloxetine, venlafaxine, milnacipran, and reboxetine increased the extracellular levels of norepinephrine and dopamine in the prefrontal cortex in SHR. Citalopram did not affect norepinephrine and dopamine levels in the prefrontal cortex, although it increased the serotonin levels. Neither duloxetine nor venlafaxine increased the dopamine levels in the striatum. These findings suggest that serotonin-norepinephrine reuptake inhibitors, similar to methylphenidate and atomoxetine, have potential for ameliorating motor abnormality in the SHR model.

Neuroprotective strategies in hippocampal neurodegeneration induced by the neurotoxicant trimethyltin

The selective vulnerability of specific neuronal subpopulations to trimethyltin (TMT), an organotin compound with neurotoxicant effects selectively involving the limbic system and especially marked in the hippocampus, makes it useful to obtain in vivo models of neurodegeneration associated with behavioural alterations, such as hyperactivity and aggression, cognitive impairment as well as temporal lobe epilepsy. TMT has been widely used to study neuronal and glial factors involved in selective neuronal death, as well as the molecular mechanisms leading to hippocampal neurodegeneration (including neuroinflammation, excitotoxicity, intracellular calcium overload, mitochondrial dysfunction and oxidative stress). It also offers a valuable instrument to study the cell-cell interactions and signalling pathways that modulate injury-induced neurogenesis, including the involvement of newly generated neurons in the possible repair processes. Since TMT appears to be a useful tool to damage the brain and study the various responses to damage, this review summarises current data from in vivo and in vitro studies on neuroprotective strategies to counteract TMT-induced neuronal death, that may be useful to elucidate the role of putative candidates for translational medical research on neurodegenerative diseases.