Impact of cannabidiol on brain glucose metabolism of C57Bl/6 male mice previously exposed to cocaine.

Despite evidence of the beneficial effects of cannabidiol (CBD) in animal models of cocaine use disorder (CUD), CBD neuronal mechanisms remain poorly understood. This study investigated the effects of CBD treatment on brain glucose metabolism, in a CUD animal model, using [18F]FDG positron emission tomography (PET). Male C57Bl/6 mice were injected with cocaine (20 mg/kg, i.p.) every other day for 9 days, followed by 8 days of CBD administration (30 mg/kg, i.p.). After 48 h, animals were challenged with cocaine. Control animals received saline/vehicle. [18F]FDG PET was performed at four time points: baseline, last day of sensitization, last day of withdrawal/CBD treatment, and challenge. Subsequently, the animals were euthanized and immunohistochemistry was performed on the hippocampus and amygdala to assess the CB1 receptors, neuronal nuclear protein, microglia (Iba1), and astrocytes (GFAP). Results showed that cocaine administration increased [18F]FDG uptake following sensitization. CBD treatment also increased [18F]FDG uptake in both saline and cocaine groups. However, animals that were sensitized and challenged with cocaine, and those receiving only an acute cocaine injection during the challenge phase, did not exhibit increased [18F]FDG uptake when treated with CBD. Furthermore, CBD induced modifications in the integrated density of NeuN, Iba, GFAP, and CB1R in the hippocampus and amygdala. This is the first study addressing the impact of CBD on brain glucose metabolism in a preclinical model of CUD using PET. Our findings suggest that CBD disrupts cocaine-induced changes in brain energy consumption and activity, which might be correlated with alterations in neuronal and glial function.

Neurotoxicity of crack cocaine exposure: evidence from a systematic review of in vitro and in vivo studies.

Several studies suggest that crack cocaine users exhibit higher prevalence of both psychiatric and psychosocial problems, with an aggressive pattern of drug use. Nevertheless, few experimental studies attempted to verify the neurotoxicity after crack cocaine exposure, especially when compared with other routes of cocaine administration. This systematic review aimed to verify whether in vitro and/or in vivo crack cocaine exposure is more neurotoxic than cocaine exposure (snorted or injected). A search was performed in the PubMed, EMBASE, Scopus, Web of Science, and LILACS databases for in vitro and in vivo toxicological studies conducted with either rats or mice, with no distinction with regard to sex or age. Other methods including BioRxiv, BDTD, Academic Google, citation searching, and specialist consultation were also adopted. Two independent investigators screened the titles and abstracts of retrieved studies and subsequently performed full-text reading and data extraction. The quality of the included studies was assessed by the Toxicological data Reliability assessment Tool (ToxRTool). The study protocol was registered with the Prospective Registry of Systematic Reviews (PROSPERO; CRD42022332250). Of the twelve studies included, three were in vitro and nine were in vivo studies. According to the ToxRTool, most studies were considered reliable either with or without restrictions, with no one being considered as not reliable. The studies found neuroteratogenic effects, decreased threshold for epileptic seizures, schizophrenic-like symptoms, and cognitive deficits to be associated with crack cocaine exposure. Moreover, both in vitro and in vivo studies reported a worsening in cocaine neurotoxic effect caused by the anhydroecgonine methyl ester (AEME), a cocaine main pyrolysis product, which is in line with the more aggressive pattern of crack cocaine use. This systematic review suggests that crack cocaine exposure is more neurotoxic than other routes of cocaine administration. However, before the scarcity of studies on this topic, further toxicological studies are necessary.

[18 F]FDG brain uptake of C57Bl/6 male mice is affected by locomotor activity after cocaine use: A small animal positron emission tomography study.

We verified if cocaine-induced peripheral activation might disrupt [18 F]FDG brain uptake after a cocaine challenge and suggested an optimal protocol to measure cocaine-induced brain metabolic alterations in mice. C57Bl/6 male mice were injected with [18 F]FDG and randomly separated into three groups. Groups 1 and 2 were kept conscious after [18 F]FDG administration and after 5 min received saline or cocaine (20 mg/kg). The animals in group 1 (n = 5) were then evaluated in the open field for 30 min and those from group 2 (n = 6) were kept alone in a home cage for the same period. Forty-five minutes after [18 F]FDG administration, images were acquired for 30 min. Group 3 (n = 6) was kept anesthetized and image acquisition started immediately after tracer injection, for 75 min. Saline (Day 1) or cocaine (Day 2) was injected 5 min after starting acquisition. Another set of animals (n = 5) were treated with cocaine every other day for 10 days or saline (n = 6) and were scanned with the dynamic protocol to verify its efficacy. [18 F]FDG uptake increased after cocaine administration when compared to baseline only in animals kept under anesthesia. No brain effect of cocaine was observed in animals submitted to the open field or kept in the home cage. The use of anesthesia is essential to visualize cocaine-induced changes in brain metabolism by [18 F]FDG PET, providing an interesting preclinical approach to investigate naïve subjects and enabling a bidirectional translational science approach for better understanding of cocaine use disorder.

Chronic escalating-dose and acute binge cocaine treatments change the hippocampal cholinergic muscarinic system on drug presence and after withdrawal.

Cocaine addiction is a relapsing disorder with loss of control in limiting drug intake. Considering the involvement of acetylcholine in the neurobiology of the disease, our aim was to evaluate whether cocaine induces plastic changes in the hippocampal cholinergic muscarinic system. Male Swiss-Webster mice received saline or cocaine (ip) three times daily (60-min intervals) either acutely or in an escalating-dose binge paradigm for 14 days. Locomotor activity was measured in all treatment days. Dopaminergic and cholinergic muscarinic receptors (D1R, D2R, M1-M5, mAChRs), choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT) and acetylcholinesterase (AChE) were quantified in the hippocampus by immunoblotting one hour after the last injection (on drug) or after 14 days of abstinence (withdrawal). Escalating-dose group showed cocaine-induced locomotor sensitization from day 2. M3 mAChR and ChAT significantly increased after the on-drug acute binge treatment. Escalating-dose on-drug group showed increased ChAT, M1, M5 mAChR and D2R; and decreased D1R. Acute-binge withdrawal group showed increased VAChT, M2 mAChR, D1R, and D2R; and decreased M1 mAChR. Escalating-dose withdrawal group presented increased D1R and VAChT and decreased M1 mAChR and D2R. Locomotor activity was negatively correlated with M1 mAChR and AChE in on-drug group and positively correlated with VAChT in withdrawal group. M1 mAChR was positively correlated with M2 mAChR and ChAT in on-drug group, whereas ChAT was positively correlated with M5 mAChR in withdrawal group. The results indicate that cocaine induced an increase in the hippocampal cholinergic tone in the presence of the drug, whereas withdrawal causes a resetting in the system.

Psychedelics and Mental Health: An Alternative Strategy to Treat Mental Impairments Triggered or Aggravated by COVID-19.

Despite the discovery of vaccines for COVID-19, one of the best security measures to contain the spread of the virus is social distancing and isolation. However, isolation might trigger negative mental outcomes, such as onset of a depressive and anxious condition, increased consumption of alcohol and drugs, relapse to substances of abuse, and even induce post-traumatic stress disorder. Interestingly, recent research with psychedelics suggests that when these substances are used in combination with psychotherapy, they may reduce these mental impairments. Nevertheless, scientists are still working to elucidate the possible mechanisms behind these phenomena.

Anhydroecgonine methyl ester, a cocaine pyrolysis product, contributes to cocaine-induced rat primary hippocampal neuronal death in a synergistic and time-dependent manner.

Crack cocaine users are simultaneously exposed to volatilized cocaine and to its main pyrolysis product, anhydroecgonine methyl ester (AEME). Although the neurotoxic effects of cocaine have been extensively studied, little is known about AEME or its combination. We investigated cell death processes using rat primary hippocampal cells exposed to cocaine (2 mM), AEME (1 mM) and their combination (C + A), after 1, 3, 6 and 12 h. Cocaine increased LC3 I after 6 h and LC3 II after 12 h, but reduced the percentage of cells with acid vesicles, suggesting failure in the autophagic flux, which activated the extrinsic apoptotic pathway after 12 h. AEME neurotoxicity did not involve the autophagic process; rather, it activated caspase-9 after 6 h and caspase-8 after 12 h leading to a high percentage of cells in early apoptosis. C + A progressively reduced the percentage of undamaged cells, starting after 3 h; it activated both apoptotic pathways after 6 h, and was more neurotoxic than cocaine and AEME alone. Also, C + A increased the phosphorylation of p62 after 12 h, but there was little difference in LC3 I or II, and a small percentage of cells with acid vesicles at all time points investigated. In summary, the present study provides new evidence for the neurotoxic mechanism and timing response of each substance alone and in combination, indicating that AEME is more than just a biological marker for crack cocaine consumption, as it may intensify and hasten cocaine neurotoxicity.

Diesel exhaust exposure intensifies inflammatory and structural changes associated with lung aging in mice.

Life expectancy is increasing worldwide. Lung aging is a process marked by changes in multiple morphological, physiological and age-related biomarkers (e.g., sirtuins) and is influenced by external factors, such as air pollution. Hence, the elderly are considered more vulnerable to the air pollution hazards. We hypothesized that diesel exhaust (DE) exposure intensifies changes in lung inflammatory and structural parameters in aging subjects. Two- and fifteen-month-old mice were exposed to DE for 30 days. Lung function was measured using the forced oscillation method. The inflammatory profile was evaluated in the bronchoalveolar lavage fluid (BALF) and blood, and lung volumes were estimated by stereology. Antioxidant enzyme activity was evaluated by spectrophotometry, sirtuin 1 (SIRT1), sirtuin 2 (SIRT2) and sirtuin 6 (SIRT6) expression was assessed by reverse transcription polymerase chain reaction (RT-PCR), and levels of the sirtuin proteins were evaluated by immunohistochemical staining in lung tissues. Older mice presented decreased pulmonary resistance and elastance, increased macrophage infiltration and decreased tumor necrosis factor (TNF) and interleukin 10 (IL-10) levels in the BALF, reduced activities of the antioxidant enzymes glutathione peroxidase (GPx) and glutathione reductase (GR), and increased activity glutathione S-transferase (GST); increased lung volumes with decreased elastic fiber and increased airway collagen content. SIRT1 gene expression was decreased in older animals, but protein levels were increased. DE exposure increased macrophage infiltration and oxidative stress in the lungs of animals of both ages. SIRT6 gene expression was decreased by DE exposure, with increased protein levels. In older animals, DE affected lung structure and collagen content. Lung aging features, such as decreased antioxidant reserves, lower IL-10 expression, and decreased SIRT1 levels may predispose subjects to exacerbated responses after DE exposure. Our data support the hypothesis that strategies designed to reduce ambient air pollution are an important step towards healthy aging.

Genotoxic and epigenotoxic effects in mice exposed to concentrated ambient fine particulate matter (PM2.5) from São Paulo city, Brazil.

BACKGROUND: The Metropolitan Area of São Paulo has a unique composition of atmospheric pollutants, and positive correlations between exposure and the risk of diseases and mortality have been observed. Here we assessed the effects of ambient fine particulate matter (PM2.5) on genotoxic and global DNA methylation and hydroxymethylation changes, as well as the activities of antioxidant enzymes, in tissues of AJ mice exposed whole body to ambient air enriched in PM2.5, which was concentrated in a chamber near an avenue of intense traffic in São Paulo City, Brazil. RESULTS: Mice exposed to concentrated ambient PM2.5 (1 h daily, 3 months) were compared to in situ ambient air exposed mice as the study control. The concentrated PM2.5 exposed group presented increased levels of the oxidized nucleoside 8-oxo-7,8-dihydro-2'-deoxyguanosine in lung and kidney DNA and increased levels of the etheno adducts 1,N6-etheno-2'-deoxyadenosine and 1,N2-etheno-2'-deoxyguanosine in kidney and liver DNA, respectively. Apart from the genotoxic effects, the exposure to PM2.5 led to decreased levels of the epigenetic mark 5-hydroxymethylcytosine (5-hmC) in lung and liver DNA. Changes in lung, liver, and erythrocyte antioxidant enzyme activities were also observed. Decreased glutathione reductase and increased superoxide dismutase (SOD) activities were observed in the lungs, while the liver presented increased glutathione S-transferase and decreased SOD activities. An increase in SOD activity was also observed in erythrocytes. These changes are consistent with the induction of local and systemic oxidative stress. CONCLUSIONS: Mice exposed daily to PM2.5 at a concentration that mimics 24-h exposure to the mean concentration found in ambient air presented, after 3 months, increased levels of DNA lesions related to the occurrence of oxidative stress in the lungs, liver, and kidney, in parallel to decreased global levels of 5-hmC in lung and liver DNA. Genetic and epigenetic alterations induced by pollutants may affect the genes committed to cell cycle control, apoptosis, and cell differentiation, increasing the chance of cancer development, which merits further investigation.

Lead exposure is related to hypercortisolemic profiles and allostatic load in Brazilian older adults.

Lead levels (Pb) have been linked to both hyper- and hypo-reactivity of hypothalamic-pituitary-adrenal axis (HPA) axis to acute stress in animals and humans. Similarly, allostatic load (AL), the 'wear and tear' of chronic stress, is associated with inadequate HPA axis activity. We examined whether Pb levels would be associated with altered diurnal cortisol profile, as a primary mediator of AL, during aging. Pb levels were measured from blood samples (BPb) of 126 Brazilian individuals (105 women), between 50 and 82 years old. Six neuroendocrine, metabolic, and anthropometric biomarkers were analyzed and values were transformed into an AL index using clinical reference cut-offs. Salivary samples were collected at home over 2 days at awakening, 30-min after waking, afternoon, and evening periods to determine cortisol levels. A multiple linear regression model showed a positive association between BPb as the independent continuous variable and cortisol awakening response (R2=0.128; B=0.791; p=0.005) and overall cortisol concentration (R2=0.266; B=0.889; p<0.001) as the outcomes. Repeated measures ANOVA showed that individuals with high BPb levels showed higher cortisol at 30min after awakening (p=0.003), and in the afternoon (p=0.002) than those with low BPb values. Regarding AL, regression model showed that BPb was positively associated with AL index (R2=0.100; B=0.204; p=0.032). Correlation analyzes with individual biomarkers showed that BPb was positively correlated with HDL cholesterol (p=0.02) and negatively correlated with DHEA-S (p=0.049). These findings suggest that Pb exposure, even at levels below the reference blood lead level for adults recommended by the National Institute for Occupational Safety and Health and by the Center for Disease Control and Prevention, may contribute to AL and dysregulated cortisol functioning in older adults. Considering these findings were based on cross-sectional data future research is needed to confirm our exploratory results.

Photobiomodulation Therapy Decreases Oxidative Stress in the Lung Tissue after Formaldehyde Exposure: Role of Oxidant/Antioxidant Enzymes.

Formaldehyde is ubiquitous pollutant that induces oxidative stress in the lung. Several lung diseases have been associated with oxidative stress and their control is necessary. Photobiomodulation therapy (PBMT) has been highlighted as a promissory treatment, but its mechanisms need to be better investigated. Our objective was to evaluate the effects of PBMT on the oxidative stress generated by FA exposure. Male Wistar rats were submitted to FA exposure of 1% or vehicle (3 days) and treated or not with PBMT (1 and 5 h after each FA exposure). Rats treated only with laser were used as control. Twenty-four hours after the last FA exposure, we analyzed the effects of PBMT on the generation of nitrites and hydrogen peroxide, oxidative burst, glutathione reductase, peroxidase, S-transferase enzyme activities, the gene expression of nitric oxide, cyclooxygenase, superoxide dismutase, the catalase enzyme, and heme oxygenase-1. PBMT reduced the generation of nitrites and hydrogen peroxide and increased oxidative burst in the lung cells. A decreased level of oxidant enzymes was observed which were concomitantly related to an increased level of antioxidants. This study provides new information about the antioxidant mechanisms of PBMT in the lung and might constitute an important tool for lung disease treatment.

Environmental tobacco smoke in the early postnatal period induces impairment in brain myelination.

Environmental tobacco smoke (ETS) is associated with high morbidity and mortality, mainly in children. However, few studies focus on the brain development effects of ETS exposure. Myelination mainly occurs in the early years of life in humans and the first three postnatal weeks in rodents and is sensitive to xenobiotics exposure. This study investigated the effects of early postnatal ETS exposure on myelination. BALB/c mice were exposed to ETS generated from 3R4F reference research cigarettes from the third to the fourteenth days of life. The myelination of nerve fibers in the optic nerve by morphometric analysis and the levels of Olig1 and myelin basic protein (MBP) were evaluated in the cerebellum, diencephalon, telencephalon, and brainstem in infancy, adolescence, and adulthood. Infant mice exposed to ETS showed a decrease in the percentage of myelinated fibers in the optic nerve, compared with controls. ETS induced a decrease in Olig1 protein levels in the cerebellum and brainstem and an increase in MBP levels in the cerebellum at infant. It was also found a decrease in MBP levels in the telencephalon and brainstem at adolescence and in the cerebellum and diencephalon at adulthood. The present study demonstrates that exposure to ETS, in a critical phase of development, affects the percentage of myelinated fibers and myelin-specific proteins in infant mice. Although we did not observe differences in the morphological analysis in adolescence and adulthood, there was a decrease in MBP levels in distinctive brain regions suggesting a delayed effect in adolescence and adulthood.

Environmental enrichment enhances ethanol preference over social reward in male swiss mice: Involvement of oxytocin-dopamine interactions.

The impact of environmental enrichment (EE) on natural rewards, including social and appetitive rewards, was investigated in male Swiss mice. EE, known for providing animals with various stimuli, was assessed for its effects on conditioned place preference (CPP) associated with ethanol and social stimuli. We previously demonstrated that EE increased the levels of the prosocial neuropeptide oxytocin (OT) in the hypothalamus and enhanced ethanol rewarding effects via an oxytocinergic mechanism. This study also investigated the impact of EE on social dominance and motivation for rewards, measured OT-mediated phospholipase C (PLC) activity in striatal membranes, and assessed OT expression in the hypothalamus. The role of dopamine in motivating rewards was considered, along with the interaction between OT and D1 receptors (DR) in the nucleus accumbens (NAc). Results showed that EE mice exhibited a preference for ethanol reward over social reward, a pattern replicated by the OT analogue Carbetocin. EE mice demonstrated increased social dominance and reduced motivation for appetitive taste stimuli. Higher OT mRNA levels in the hypothalamus were followed by diminished OT receptor (OTR) signaling activity in the striatum of EE mice. Additionally, EE mice displayed elevated D1R expression, which was attenuated by the OTR antagonist (L-368-889). The findings underscore the reinforcing effect of EE on ethanol and social rewards through an oxytocinergic mechanism. Nonetheless, they suggest that mechanisms other than the prosocial effect of EE may contribute to the ethanol pro-rewarding effect of EE and Carbetocin. They also point towards an OT-dopamine interaction potentially underlying some of these effects.

Serotonergic neuromodulation of synaptic plasticity.

Synaptic plasticity constitutes a fundamental process in the reorganization of neural networks that underlie memory, cognition, emotional responses, and behavioral planning. At the core of this phenomenon lie Hebbian mechanisms, wherein frequent synaptic stimulation induces long-term potentiation (LTP), while less activation leads to long-term depression (LTD). The synaptic reorganization of neuronal networks is regulated by serotonin (5-HT), a neuromodulator capable of modify synaptic plasticity to appropriately respond to mental and behavioral states, such as alertness, attention, concentration, motivation, and mood. Lately, understanding the serotonergic Neuromodulation of synaptic plasticity has become imperative for unraveling its impact on cognitive, emotional, and behavioral functions. Through a comparative analysis across three main forebrain structures-the hippocampus, amygdala, and prefrontal cortex, this review discusses the actions of 5-HT on synaptic plasticity, offering insights into its role as a neuromodulator involved in emotional and cognitive functions. By distinguishing between plastic and metaplastic effects, we provide a comprehensive overview about the mechanisms of 5-HT neuromodulation of synaptic plasticity and associated functions across different brain regions.

Lifetime caffeine and adolescent nicotine exposure in mice: effects on anxiety-like behavior and reward.

Caffeine consumption occurs throughout life, while nicotine use typically begins during adolescence, the period when caffeine-nicotine epidemiological association begins in earnest. Despite that, few studies in animal models parallel the pattern of coexposure that occurs in humans. Therefore, the neurobehavioral consequences of the association between these drugs remain unclear. Here, we exposed Swiss mice to lifetime caffeine. Caffeine solutions of 0.1 g/L (CAF0.1), 0.3 g/L (CAF0.3), or water (CTRL) were used as the sole liquid source, being offered to progenitors until weaning and, after that, directly to the offspring until the last day of adolescent behavioral evaluation. The open field test was used to evaluate acute effects of nicotine, of lifetime caffeine and of their interaction on locomotion and anxiety-like behavior, while the conditioned place preference test was used to assess the impact of caffeine on nicotine (0.5 mg/Kg, i.p.) reward. Frontal cerebral cortex dopamine content, dopamine turnover, and norepinephrine levels, as well as hippocampal serotonin 1A receptor expression were assessed. CAF0.3 mice exhibited an increase in anxiety-like behavior when compared to CAF0.1 and CTRL ones, but nicotine coexposure mitigated the anxiogenic-like caffeine-induced effect. Distinctively, caffeine had no effect on locomotion and failed to interfere with both nicotine-induced hyperactivity and place preference. There were no significant effects on dopaminergic and serotonergic markers. In conclusion, although caffeine did not affect nicotine reward, considering the strong association between anxiety disorders and tobacco consumption, caffeine-induced anxiety-like behavior advises limiting its consumption during development, including adolescence, as caffeine could be a risk factor to nicotine use.

Protective effects of aerobic exercise on acute lung injury induced by LPS in mice.

INTRODUCTION: The regular practice of physical exercise has been associated with beneficial effects on various pulmonary conditions. We investigated the mechanisms involved in the protective effect of exercise in a model of lipopolysaccharide (LPS)-induced acute lung injury (ALI). METHODS: Mice were divided into four groups: Control (CTR), Exercise (Exe), LPS, and Exercise + LPS (Exe + LPS). Exercised mice were trained using low intensity daily exercise for five weeks. LPS and Exe + LPS mice received 200 µg of LPS intratracheally 48 hours after the last physical test. We measured exhaled nitric oxide (eNO); respiratory mechanics; neutrophil density in lung tissue; protein leakage; bronchoalveolar lavage fluid (BALF) cell counts; cytokine levels in BALF, plasma and lung tissue; antioxidant activity in lung tissue; and tissue expression of glucocorticoid receptors (Gre). RESULTS: LPS instillation resulted in increased eNO, neutrophils in BALF and tissue, pulmonary resistance and elastance, protein leakage, TNF-alpha in lung tissue, plasma levels of IL-6 and IL-10, and IL-1beta, IL-6 and KC levels in BALF compared to CTR (P ≤0.02). Aerobic exercise resulted in decreases in eNO levels, neutrophil density and TNF-alpha expression in lung tissue, pulmonary resistance and elastance, and increased the levels of IL-6, IL-10, superoxide dismutase (SOD-2) and Gre in lung tissue and IL-1beta in BALF compared to the LPS group (P ≤0.04). CONCLUSIONS: Aerobic exercise plays important roles in protecting the lungs from the inflammatory effects of LPS-induced ALI. The effects of exercise are mainly mediated by the expression of anti-inflammatory cytokines and antioxidants, suggesting that exercise can modulate the inflammatory-anti-inflammatory and the oxidative-antioxidative balance in the early phase of ALI.

Environmental tobacco smoke induces oxidative stress in distinct brain regions of infant mice.

Environmental tobacco smoke (ETS) leads to the death of 600,000 nonsmokers annually and is associated with disturbances in antioxidant enzyme capacity in the adult rodent brain. However, little is known regarding the influence of ETS on brain development. The aim of this study was to determine levels of malonaldehyde (MDA) and 3-nitrotyrosine (3-NT), as well as enzymatic antioxidant activities of glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), and superoxide dismutase (SOD), in distinct brain structures. BALB/c mice were exposed to ETS twice daily for 1 h from postnatal day 5 through postnatal day 18. Acute exposure was performed for 1 h on postnatal day 18. Mice were euthanized either immediately (0) or 3 h after the last exposure. Immediately after an acute exposure there were higher GR and GST activities and MDA levels in the hippocampus, higher GPx and SOD activities in the prefrontal cortex, and higher GST activity and MDA levels in the striatum and cerebellum. Three hours later there was an increase in SOD activity and MDA levels in the hippocampus and a decrease in the activity of all enzymes in the prefrontal cortex. Immediately after final repeated exposure there were elevated levels of GST and GR activity and decreased GPx activity in the hippocampus. Moreover, a rise was found in GPx and GST activities in the prefrontal cortex and increased GST and GPx activity in the striatum and cerebellum, respectively. After 3 h the prefrontal cortex showed elevated GR and GST activities, and the striatum displayed enhanced GST activity. Data showed that enzymatic antioxidant system in the central nervous system responds to ETS differently in different regions of the brain and that a form of adaptation occurs after several days of exposure.

Association between awakening cortisol levels and cardiovascular performance in sugarcane rural workers.

Sudden deaths without known causes have been reported among rural workers in the last decade, especially in low and middle-income countries. The current study aimed to analyse the association between awakening cortisol response and cardiovascular performance in rural workers before and after the harvesting period. Fifty-four rural male workers and 48 residents were included (non-rural workers) from a sugarcane production area in São Paulo, Brazil. Morning salivary cortisol were analysed before and 7 months after the beginning of burnt sugarcane harvesting. Cardiovascular performance (blood pressure, pulse pressure and heart rate HR) was evaluated using the Incremental Shuttle Walking Test (ISWT). Our findings revealed a negative association between CAR and cardiovascular performance in rural workers at the harvesting period. Specifically, morning cortisol levels significantly increased after seven months of intense harvesting activity, allied to improvements in physical performance, systolic blood pressure and heart rate reactivity to a cardiopulmonary task. No association was observed in the resident group. Altogether, these findings suggest that, at least in the short-term, rural workers presented an adaptive response to the physical demands of sugarcane harvesting work. Longitudinal studies are essential to investigate the long-term effects of harvesting activity on rural workers' health.

Neurotoxicity Assessment of 1-[(2,3-Dihydro-1-Benzofuran-2-yl)Methyl]Piperazine (LINS01 Series) Derivatives and their Protective Effect on Cocaine-Induced Neurotoxicity Model in SH-SY5Y Cell Culture.

Excessive levels of dopamine in the synaptic cleft, induced by cocaine for example, activates dopaminergic receptors, mainly D1R, D2R, and D3R subtypes, contributing to neurotoxic effects. New synthetic 1-[(2,3-dihydro-1-benzofuran-2-yl)methyl]piperazine derivatives (the LINS01 compounds), designed as histaminergic receptor (H3R) ligands, are also dopaminergic receptor ligands, mainly D2R and D3R. This study aims to evaluate the neurotoxicity of these new synthetic LINS01 compounds (LINS01003, LINS01004, LINS01011, and LINS01018), as well as to investigate their protective potential on a cocaine model of dopamine-induced neurotoxicity using SH-SY5Y cell line culture. Neurotoxicity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), and automated cell counting with fluorescent dyes (acridyl orange and propidium iodide) assays. Concentration-response curves (CRCs) were performed for all LINS compounds and cocaine using MTT assay. The results show that LINS series did not decrease cell viability after 48h of exposure-except for 100 µM LINS01018, which was discontinued from the study. Likewise, MTT, LDH, and fluorescent dyes staining showed no difference is cell viability for LINS compounds at 10 µM. When incubated with 2.5 mM cocaine (lethal concentration 50) for 48h, 10 µM of each LINS compound, metoclopramide (D2R antagonist) and haloperidol (D2R/D3R antagonist), ameliorated cocaine-induced neurotoxicity. However, only metoclopramide, haloperidol, and LINS01011 compound significantly decreased LDH released in the culture medium, suggesting that this new synthetic compound presents a more robust effect. This preliminary in vitro neurotoxicity study suggests that LINS01 compounds are not neurotoxic, and that they play a promising role in preventing cocaine-induced neurotoxicity.

Ayahuasca, a psychedelic beverage, modulates neuroplasticity induced by ethanol in mice.

Alcohol use disorder needs more effective treatments because relapse rates remain high. Psychedelics, such as ayahuasca, have been used to treat substance use disorders. Our study aimed to evaluate the effects of ayahuasca on ethanol-induced behavioral sensitization (EIBS). Swiss mice received 2.2 g/kg ethanol or saline IP injections every other day across nine days (D1, D3, D5, D7, and D9), and locomotor activity was evaluated 10 min after each injection. Then, animals were treated daily with ayahuasca (corresponding to 1.76 mg/kg of N,N-dimethyltryptamine, DMT) or water by oral gavage for eight consecutive days. On the seventh day, mice were evaluated in the elevated plus maze. Then, mice were challenged with a single dose of ethanol to measure their locomotor activity. Dopamine receptors, serotonin receptors, dynorphin, and prodynorphin levels were quantified in the striatum and hippocampus by blot analysis. Repeated ethanol administration resulted in EIBS. However, those animals treated with ayahuasca had an attenuated EIBS. Moreover, ayahuasca reduced the anxiogenic response to ethanol withdrawal and prevented the ethanol-induced changes on 5-HT1a receptor and prodynorphin levels in the hippocampus and reduced ethanol effects in the dynorphin/prodynorphin ratio levels in the striatum. These results suggest a potential application of ayahuasca to modulate the neuroplastic changes induced by ethanol.

Nicotine exposure through breastfeeding affects brain-derived neurotrophic factor and synaptic proteins levels in the brain of stressed adult female mice.

Nicotine has been used during pregnancy and lactation as a tobacco harm reduction strategy. However, it is unclear whether nicotine exposure during a critical development period negatively impacts stress responses in adulthood. This study investigated how nicotine, administered via breastfeeding, affects the brain-derived neurotrophic factor (BDNF), synaptic proteins levels, and anxiety-like behavior in adult female mice subjected to stress. Female Swiss mice were exposed to saline or nicotine (8 mg/kg/day) through breastfeeding between their fourth and 17th postnatal days (P) via implanted osmotic mini pumps. The unpredictable chronic mild stress (UCMS) protocol was performed during their adulthood (P65) for 10 consecutive days, followed by the elevated plus maze (EPM) test 1 day after the protocol. Animals were euthanized and their blood, collected for plasma corticosterone measurements and their brain structures, dissected for BDNF and synaptic proteins analyses. We found no significant differences in corticosterone levels between groups (Saline/Non-stress, Nicotine/Non-stress, Saline/Stress, and Nicotine/Stress). The UCMS protocol hindered weight gain. Mice exposed to nicotine through breastfeeding with or without the UCMS protocol in adulthood showed higher grooming and head dipping frequency; decreased BDNF levels in cerebellum and striatum; increased postsynaptic density protein 95 (PSD-95), synapsin I, and synaptophysin levels in cerebellum; and decreased PSD-95 and synapsin I levels in brainstem. Our results indicate that nicotine exposure through breastfeeding leads to long-lasting behavioral effects and synaptic protein changes, most of which were independent of the UCMS protocol, even after a long nicotine-free period, highlighting the importance of further studies on nicotine exposure during development.