Ferrostatin-1 mitigates cellular damage in a ferroptosis-like environment in Caenorhabditis elegans.

Although iron (Fe) is the most biologically abundant transition metal, it is highly toxic when it accumulates as Fe2+, forming a labile Fe pool and favoring the Fenton reaction. This oxidative scenario leads to a type of caspase-independent programmed cell death, referred to as ferroptosis, where following processes take place: (i) Fe2+ overload, (ii) glutathione peroxidase 4 inactivation, (iii) lipid peroxidation, and (iv) glutathione depletion. The present study sought to evaluate the consequences of Fe2+ administration on ferroptosis induction in Caenorhabditis elegans. We demonstrated higher mortality, increased lipid peroxidation, reduced glutathione peroxidase activity, and morphological damage in dopaminergic neurons upon Fe2+ overload. Pharmacological intervention at the level of lipid peroxidation with ferrostatin-1 (250 µM) mitigated the damage and returned the biochemical parameters to basal levels, revealing the potential of this therapeutical approach. Finally, to assess the relationship between ferroptosis and dopamine in a Parkinsonian background, we evaluated the UA44 worm strain which overexpresses the alpha-synuclein protein in cherry-labeled dopaminergic neurons. We demonstrated that Fe2+ administration reduced lethality associated with similar alterations in biochemical and dopaminergic morphological parameters in wild-type animals. These experiments provide mechanistic-based evidence on the efficacy of a pharmacological approach to mitigate the physiological, biochemical, and morphological consequences of Fe2+ overload. At the same time, they encourage further research on the impact of the combined effects resulting from the genetic background and dopamine signaling in a Parkinsonian phenotype.

Enduring Ethanol-Induced Behavioral Alterations in Caenorhabditis elegans After Developmental Lead Exposure.

The roundworm Caenorhabditis elegans (C. elegans) has become a powerful tool to evaluate the deleterious effects of early-life exposure to xenobiotics, including metals. The present chapter describes a detailed protocol for developmental lead (Pb)-exposure in C. elegans. Preliminary assays as well as the final procedure are described in detail. In addition, further protocols aimed to assess ethanol exposure at later stages of life demonstrate the impact of this drug on locomotor behavior, revealing the enduring effects that Pb can imprint on this organism when exposure occurs during development.

Low-dose N-acetyl cysteine prevents paraquat-induced mortality in Caenorhabditis elegans.

Exposure to the herbicide paraquat (PQ; 1,1'-dimethyl-4,4'-bipyridinium dichloride) affects the redox balance of the cell, an effect that can be restored by antioxidants, including N-acetyl cysteine (NAC). One hour of exposure to PQ (0 mM, 10 mM, 50 mM, or 100 mM) dose-dependently increased mortality in Caenorhabditis elegans after exposure (immediate toxicity), while this effect was more evident 24 hours thereafter (delayed toxicity). Importantly, pretreatment with NAC 0.5 mM for one hour partially prevented mortality in the immediate assay, while it had no effect in the delayed test, revealing the importance of long-term studies when evaluating toxicity.

Developmental lead exposure affects dopaminergic neuron morphology and modifies basal slowing response in Caenorhabditis elegans: Effects of ethanol.

Lead (Pb) and ethanol (EtOH) are neurotoxicants that affect the dopaminergic (DAergic) system. We first sought to assess the morphology of the DAergic neurons in the Caenorhabditis elegans BY200 strain. The results demonstrated dose-dependent damage in these neurons induced by developmental Pb exposure. Secondly, transgenic worms exposed to 24 µM Pb and administered with 200 mM EtOH were evaluated in the basal slowing response (BSR). Pb induced impairment in the BSR in the wild-type strain that did not improve in response to EtOH, an effect also observed in strains that lack the DOP-1, DOP-2, and DOP-3 receptors. The animals that overexpress tyrosine hydroxylase (TH), or lack the vesicular transport (VMAT) showed a Pb-induced impairment in the BSR that seemed to improve after EtOH. Interestingly, a dramatic impairment in the BSR was observed in the Pb group in strains lacking the DOP-4 receptor, resembling the response of the TH-deficient strain, an effect that in both cases showed a non-significant reversal by EtOH. These results suggest that the facilitatory effect of EtOH on the impaired BSR observed in Pb-exposed null mutant strains may be the result of a compensatory effect in the altered DAergic synapse present in these animals.

Exposición ambiental a plomo y biomarcadores de estrés oxidativo en niños sanos de La Plata, Argentina / Environmental exposure to lead and oxidative stress biomarkers among healthy children in La Plata, Argentina

Introducción. La exposición ambiental a plomo (Pb) aún constituye un problema de salud pública, particularmente para los niños. El estrés oxidativo podría representar un mecanismo primario asociado a su toxicidad. El objetivo del presente estudio fue determinar los niveles de Pb en sangre (Pb-S) en niños de 1 a 6 años de La Plata y alrededores con exposición ambiental, y su relación con biomarcadores de estrés oxidativo. Población y métodos. Estudio analítico de corte transversal. Se evaluaron niños clínicamente sanos de 1 a 6 años. Se determinaron los niveles de Pb-S, las actividades de enzimas antioxidantes y el grado de peroxidación lipídica. Se utilizó el paquete estadístico R versión 3.5.1. Resultados. Participaron 131 niños, mediana de edad 2,33 años. La media geométrica de los niveles de Pb-S fue 1,90 µg/dL; el 32 % presentó plombemias cuantificables y el 3 %, niveles ≥5 µg/dL (referencia internacional). Al comparar los biomarcadores de estrés oxidativo según los niveles de Pb-S, solo se observó diferencia significativa entre las medianas de las sustancias reactivas al ácido tiobarbitúrico (TBARS): 12,0 versus 10,0 nmol MDA/mL plasma; p = 0,02. Asimismo, la correlación entre las plombemias y las TBARS fue positiva (r = 0,24; p = 0,012). Conclusiones. La mayoría de los niños mostraron niveles de Pb-S menores a los límites recomendados por agencias internacionales, que si bien, no producen alteraciones en la actividad de enzimas antioxidantes, sí inducen peroxidación lipídica. Estos resultados reflejan la utilidad de este biomarcador como una herramienta diagnóstica temprana para evaluar los efectos subtóxicos del Pb.

Introduction. Environmental exposure to lead is still a major public health problem, especially in children. Oxidative stress may be a primary mechanism associated with toxicity. Theobjective of this study was to measure blood lead levels (BLLs) in children aged 1 to 6 years expos to lead in La Plata and suburban areas and their relation to oxidative stress biomarkers. Population and methods. Cross-sectional,analytical study. Clinically healthy children aged1 to 6 years were analyzed. BLLs, antioxidant enzyme activity, and extent of lipid peroxidation were measured. The statistical softwarepackage R, version 3.5.1, was used. Results. A total of 131 children participated; their median age was 2.33 years. The geometric mean of BLLs was 1.90 µg/dL; 32% showed a measurable BLL and 3%, BLLs ≥ 5 µg/dL (international reference). The comparison ofoxidative stress biomarkers based on BLshowed a significant difference in median thiobarbituric acid reactive substances (TBARS):12.0 versus 10.0 nmol MDA/mL of plasma;p = 0.02. In addition, the correlation between BLLs and TBARS was positive (r = 0.24; p = 0.012 Conclusions. Most children had a BLL below the limit recommended by international agencies; although such BLLs do not affantioxidant enzyme activity, they can induce lipid peroxidation. These results demonstrate theusefulness of this biomarker as an early diagnosistool to assess subtoxic lead effects.

Environmental exposure to lead and oxidative stress biomarkers among healthy children in La Plata, Argentina. / Exposición ambiental a plomo y biomarcadores de estrés oxidativo en niños sanos de La Plata, Argentina.

INTRODUCTION: Environmental exposure to lead is still a major public health problem, especially in children. Oxidative stress may be a primary mechanism associated with toxicity. The objective of this study was to measure blood lead levels (BLLs) in children aged 1 to 6 years exposed to lead in La Plata and suburban areas and their relation to oxidative stress biomarkers. POPULATION AND METHODS: Cross-sectional, analytical study. Clinically healthy children aged 1 to 6 years were analyzed. BLLs, antioxidant enzyme activity, and extent of lipid peroxidation were measured. The statistical software package R, version 3.5.1, was used. RESULTS: A total of 131 children participated; their median age was 2.33 years. The geometric mean of BLLs was 1.90 µg/dL; 32% showed a measurable BLL and 3%, BLLs ≥ 5 µg/dL (international reference). The comparison of oxidative stress biomarkers based on BLLs showed a significant difference in median thiobarbituric acid reactive substances (TBARS): 12.0 versus 10.0 nmol MDA/mL of plasma; p = 0.02. In addition, the correlation between BLLs and TBARS was positive (r = 0.24; p = 0.012). CONCLUSIONS: Most children had a BLL below the limit recommended by international agencies; although such BLLs do not affect antioxidant enzyme activity, they can induce lipid peroxidation. These results demonstrate the usefulness of this biomarker as an early diagnosis tool to assess subtoxic lead effects.

Introducción. La exposición ambiental a plomo (Pb) aún constituye un problema de salud pública, particularmente para los niños. El estrés oxidativo podría representar un mecanismo primario asociado a su toxicidad. El objetivo del presente estudio fue determinar los niveles de Pb en sangre (Pb-S) en niños de 1 a 6 años de La Plata y alrededores con exposición ambiental, y su relación con biomarcadores de estrés oxidativo. Población y métodos. Estudio analítico de corte transversal. Se evaluaron niños clínicamente sanos de 1 a 6 años. Se determinaron los niveles de Pb-S, las actividades de enzimas antioxidantes y el grado de peroxidación lipídica. Se utilizó el paquete estadístico R versión 3.5.1. Resultados. Participaron 131 niños, mediana de edad 2,33 años. La media geométrica de los niveles de Pb-S fue 1,90 µg/dL; el 32 % presentó plombemias cuantificables y el 3 %, niveles ≥5 µg/dL (referencia internacional). Al comparar los biomarcadores de estrés oxidativo según los niveles de Pb-S, solo se observó diferencia significativa entre las medianas de las sustancias reactivas al ácido tiobarbitúrico (TBARS): 12,0 versus 10,0 nmol MDA/mL plasma; p = 0,02. Asimismo, la correlación entre las plombemias y las TBARS fue positiva (r = 0,24; p = 0,012). Conclusiones. La mayoría de los niños mostraron niveles de Pb-S menores a los límites recomendados por agencias internacionales, que si bien, no producen alteraciones en la actividad de enzimas antioxidantes, sí inducen peroxidación lipídica. Estos resultados reflejan la utilidad de este biomarcador como una herramienta diagnóstica temprana para evaluar los efectos subtóxicos del Pb.

Minocycline prevents chronic restraint stress-induced vulnerability to developing cocaine self-administration and associated glutamatergic mechanisms: a potential role of microglia.

Stressful experience-induced cocaine-related behaviors are associated with a significant impairment of glutamatergic mechanisms in the Nucleus Accumbens core (NAcore). The hallmarks of disrupted glutamate homeostasis following restraint stress are the enduring imbalance of glutamate efflux after a cocaine stimulus and increased basal concentrations of extracellular glutamate attributed to GLT-1 downregulation in the NAcore. Glutamate transmission is tightly linked to microglia functioning. However, the role of microglia in the biological basis of stress-induced addictive behaviors is still unknown. By using minocycline, a potent inhibitor of microglia activation with anti-inflammatory properties, we determined whether microglia could aid chronic restraint stress (CRS)-induced glutamate homeostasis disruption in the NAcore, underpinning stress-induced cocaine self-administration. In this study, adult male rats were restrained for 2 h/day for seven days (day 1-7). From day 16 until completing the experimental protocol, animals received a vehicle or minocycline treatment (30 mg/Kg/12h i.p.). On day 21, animals were assigned to microscopic, biochemical, neurochemical or behavioral studies. We confirm that the CRS-induced facilitation of cocaine self-administration is associated with enduring GLT-1 downregulation, an increase of basal extracellular glutamate and postsynaptic structural plasticity in the NAcore. These alterations were strongly related to the CRS-induced reactive microglia and increased TNF-α mRNA and protein expression, since by administering minocycline, the impaired glutamate homeostasis and the facilitation of cocaine self-administration were prevented. Our findings are the first to demonstrate that minocycline suppresses the CRS-induced facilitation of cocaine self-administration and glutamate homeostasis disruption in the NAcore. A role of microglia is proposed for the development of glutamatergic mechanisms underpinning stress-induced vulnerability to cocaine addiction.

MOLECULAR MECHANISMS OF LEAD NEUROTOXICITY.

Lead (Pb2+) is a non-essential metal with numerous industrial applications that have led to ts ubiquity in the environment. Thus, not only occupational-exposed individuals' health is compromised, but also that of the general population and in particular children. Notably, although the central nervous system is particularly susceptible to Pb2+, other systems are affected as well. The present study focuses on molecular mechanisms that underlie the effects that arise from the presence of Pb2+ in situ in the brain, and the possible toxic effects that follows. As the brain barriers represent the first target of systemic Pb2+, mechanisms of Pb2+ entry into the brain are discussed, followed by a detailed discussion on neurotoxic mechanisms, with special emphasis on theories of ion mimicry, mitochondrial dysfunction, redox imbalance, and neuroinflammation. Most importantly, the confluence and crosstalk between these events is combined into a cogent mechanism of toxicity, by intertwining recent and old evidences from humans, in vitro cell culture and experimental animals. Finally, pharmacological interventions, including chelators, antioxidants substances, anti-inflammatory drugs, or their combination are reviewed as integrated approaches to ameliorate Pb2+ harmful effects in both developing or adult organisms.

CB1R activation in nucleus accumbens core promotes stress-induced reinstatement of cocaine seeking by elevating extracellular glutamate in a drug-paired context.

Preclinical models of stress-induced relapse to drug use have shown that the dysregulation of glutamatergic transmission within the nucleus accumbens (NA) contributes notably to the reinstatement of cocaine-seeking behavior in rodents. In this sense, there has been increasing interest in the cannabinoid type-1 receptor (CB1R), due to its crucial role in modulating glutamatergic neurotransmission within brain areas involved in drug-related behaviors. This study explored the involvement of CB1R within the NA subregions in the restraint stress-induced reinstatement of cocaine-conditioned place preference (CPP), as well as in the regulation of glutamatergic transmission, by using a pharmacological approach and the in vivo microdialysis sampling technique in freely moving rats. CB1R blockade by the antagonist/inverse agonist AM251 (5 nmol/0.5 µl/side) or CB1R activation by the agonist ACEA (0.01 fmol/0.5 µl/side), prevented or potentiated restraint stress-induced reinstatement of cocaine-CPP, respectively, after local administration into NAcore, but not NAshell. In addition, microdialysis experiments demonstrated that restraint stress elicited a significant increase in extracellular glutamate in NAcore under reinstatement conditions, with the local administration of AM251 or ACEA inhibiting or potentiating this, respectively. Interestingly, this rise specifically corresponded to the cocaine-associated CPP compartment. We also showed that this context-dependent change in glutamate paralleled the expression of cocaine-CPP, and disappeared after the extinction of this response. Taken together, these findings demonstrated the key role played by CB1R in mediating reinstatement of cocaine-CPP after restraint stress, through modulation of the context-specific glutamate release within NAcore. Additionally, CB1R regulation of basal extracellular glutamate was demonstrated and proposed as the underlying mechanism.

Brain ethanol-metabolizing enzymes are differentially expressed in lead-exposed animals after voluntary ethanol consumption: Pharmacological approaches.

Developmentally-lead (Pb)-exposed rats showed an enhanced vulnerability to the stimulating and motivational effects of ethanol (EtOH). This is accompanied by differential activity of the brain EtOH-metabolizing enzymes catalase (CAT) and mitochondrial aldehyde dehydrogenase (ALDH2). Based on the theory that brain acetaldehyde accumulation is associated with the reinforcing properties of EtOH, this study sought to determine brain CAT and ALDH2 expression in limbic areas of control and Pb-exposed animals after voluntary EtOH intake. Thirty-five-day-old rats perinatally exposed to 220 ppm Pb were offered with water or increasing EtOH solutions (2-10% v/v) during 28 days until postnatal day (PND) 63. Once intake was stable, the animals were administered: 1) saline (SAL; test days 21-24 or 21-28, as corresponds), or 2) a CAT inhibitor: 3-amine 1, 2, 4-triazole (AT; 250 mg/kg intraperitoneally [i.p.], 5 h before the last eight EtOH intake sessions -test days 21-24 and 25-28), or 3) a CAT booster: 3-nitropropionic acid (3NPA; 20 mg/kg subcutaneously [s.c.], 45 min before the last four EtOH intake sessions -test days 25-28). Two additional groups were centrally-administered cyanamide (CY, an ALDH2 inhibitor, 0.3 mg i.c.v. immediately before the last four EtOH sessions, test days 25-28) or its corresponding vehicle (VEH). Lead exposure increased EtOH intake, an effect potentiated in both groups by 3NPA or CY pretreatments and reduced by AT, albeit selectivity in the Pb group. Catalase abundance in limbic areas parallels these observations in the Pb group, showing higher CAT expression in all areas after EtOH consumption respect to the controls, an effect prevented by AT administration. In contrast, ALDH2 expression was reduced in the Pb animals after EtOH intake, with CY potentiating this effect in all brain areas under study. Based on these results and on previous evidences, we suggest that Pb exposure promotes acetaldehyde accumulation in limbic regions, providing some insights into the mechanism of action that underlies the vulnerability to the excessive EtOH consumption reported in these animals.

Silencing brain catalase expression reduces ethanol intake in developmentally-lead-exposed rats.

Lead (Pb) is a developmental neurotoxicant. We have demonstrated that perinatally Pb-exposed rats consume more ethanol than their control counterparts, a response that seems to be mediated by catalase (CAT) and centrally-formed acetaldehyde, ethanol's first metabolite with attributed reinforcing effects in the brain. The present study sought to disrupt ethanol intake (2-10% ethanol v/v) in rats exposed to 220 ppm Pb or filtered water during gestation and lactation. Thus, to block brain CAT expression, a lentiviral vector coding for a shRNA against CAT (LV-antiCAT vector) was microinfused in the posterior ventral tegmental area (pVTA) either at the onset or towards the end of a chronic voluntary ethanol consumption test. At the end of the study, rats were euthanized and pVTA dissected to measure CAT expression by Western blot. The LV-antiCAT vector administration not only reversed, but also prevented the emergence of the elevated ethanol intake reported in the perinatally Pb-exposed animals, changes that were supported by a significant reduction in CAT expression in the pVTA. These results provide further evidence of the crucial role of this enzyme in the reinforcing properties of ethanol and in the impact of the perinatal Pb programming to challenging events later in life.

Aldehyde dehydrogenase 2 in the spotlight: The link between mitochondria and neurodegeneration.

Growing body of evidence suggests that mitochondrial dysfunctions and resultant oxidative stress are likely responsible for many neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Aldehyde dehydrogenase (ALDH) superfamily plays a crucial role in several biological processes including development and detoxification pathways in the organism. In particular, ALDH2 is crucial in the oxidative metabolism of toxic aldehydes in the brain, such as catecholaminergic metabolites (DOPAL and DOPEGAL) and the principal product of lipid peroxidation process 4-HNE. This review aims to deepen the current knowledge regarding to ALDH2 function and its relation with brain-damaging processes that increase the risk to develop neurodegenerative disorders. We focused on relevant literature of what is currently known at molecular and cellular levels in experimental models of these pathologies. The understanding of ALDH2 contributions could be a potential target in new therapeutic approaches for PD and AD due to its crucial role in mitochondrial normal function maintenance that protects against neurotoxicity.

Flavonoids as protective agents against oxidative stress induced by gentamicin in systemic circulation. Potent protective activity and microbial synergism of luteolin.

The flavonoids effect on gentamicin (GEN)-induced oxidative stress (OS) in systemic circulation was evaluated in terms of reactive oxygen species (ROS) production, enzymatic antioxidant defenses superoxide dismutase (SOD) and catalase (CAT), and lipid peroxidation (LP) in vitro on human leukocytes and in vivo on rat whole blood. The inhibitory activity of ROS was ATS < QTS < isovitexin < vitexin < luteolin. Luteolin, the most active, showed more inhibition in ROS production than vitamin C (reference inhibitor) in mononuclear cells and a slightly lower protective behavior compared to this inhibitor in polymorphonuclear cells. In both cellular systems, luteolin tends to level SOD and CAT activities modified by GEN, reaching basal values and preventing LP. In Wistar rats, GEN plus luteolin can suppress ROS generation, collaborate with SOD and CAT and diminish LP produced by GEN at therapeutic doses. Finally, luteolin and antibiotic association was evaluated on the antimicrobial activity in S. aureus and E. coli showing a synergism between GEN and luteolin on S. aureus ATCC and an additive effect on E. coli ATCC. Therefore, simultaneous administration of luteolin and GEN could represent a potential therapeutic option capable of protecting the host against OS induced by GEN in the systemic circulation while enhancing the antibacterial activity of GEN.

Modulation of Ethanol-Metabolizing Enzymes by Developmental Lead Exposure: Effects in Voluntary Ethanol Consumption.

This review article provides evidence of the impact of the environmental contaminant lead (Pb) on the pattern of the motivational effects of ethanol (EtOH). To find a mechanism that explains this interaction, the focus of this review article is on central EtOH metabolism and the participating enzymes, as key factors in the modulation of brain acetaldehyde (ACD) accumulation and resulting effect on EtOH intake. Catalase (CAT) seems a good candidate for the shared mechanism between Pb and EtOH due to both its antioxidant and its brain EtOH-metabolizing properties. CAT overactivation was reported to increase EtOH consumption, while CAT blockade reduced it, and both scenarios were modified by Pb exposure, probably as the result of elevated brain and blood CAT activity. Likewise, the motivational effects of EtOH were enhanced when brain ACD metabolism was prevented by ALDH2 inhibition, even in the Pb animals that evidenced reduced brain ALDH2 activity after chronic EtOH intake. Overall, these results suggest that brain EtOH metabolizing enzymes are modulated by Pb exposure with resultant central ACD accumulation and a prevalence of the reinforcing effects of the metabolite in brain against the aversive peripheral ACD accumulation. They also support the idea that early exposure to an environmental contaminant, even at low doses, predisposes at a later age to differential reactivity to challenging events, increasing, in this case, vulnerability to acquiring addictive behaviors, including excessive EtOH intake.

Developmental lead exposure induces opposite effects on ethanol intake and locomotion in response to central vs. systemic cyanamide administration.

Lead (Pb) is a developmental neurotoxicant that elicits differential responses to drugs of abuse. Particularly, ethanol consumption has been demonstrated to be increased as a consequence of environmental Pb exposure, with catalase (CAT) and brain acetaldehyde (ACD, the first metabolite of ethanol) playing a role. The present study sought to interfere with ethanol metabolism by inhibiting ALDH2 (mitochondrial aldehyde dehydrogenase) activity in both liver and brain from control and Pb-exposed rats as a strategy to accumulate ACD, a substance that plays a major role in the drug's reinforcing and/or aversive effects. To evaluate the impact on a 2-h chronic voluntary ethanol intake test, developmentally Pb-exposed and control rats were administered with cyanamide (CY, an ALDH inhibitor) either systemically or intracerebroventricularly (i.c.v.) on the last 4 sessions of the experiment. Furthermore, on the last session and after locomotor activity was assessed, all animals were sacrificed to obtain brain and liver samples for ALDH2 and CAT activity determination. Systemic CY administration reduced the elevated ethanol intake already reported in the Pb-exposed animals (but not in the controls) accompanied by liver (but not brain) ALDH2 inactivation. On the other hand, a 0.3 mg i.c.v. CY administration enhanced both ethanol intake and locomotor activity accompanied by brain ALDH2 inactivation in control animals, while an increase in ethanol consumption was also observed in the Pb-exposed group, although in the absence of brain ALDH2 blockade. No changes were observed in CAT activity as a consequence of CY administration. These results support the participation of liver and brain ACD in ethanol intake and locomotor activity, responses that are modulated by developmental Pb exposure.

NMDA antagonist MK 801 in nucleus accumbens core but not shell disrupts the restraint stress-induced reinstatement of extinguished cocaine-conditioned place preference in rats.

Relapse is a common feature of cocaine addiction. In rodents, it can be elicited by cues, stress or the drug. Restraint stress-induced reinstatement of cocaine-conditioned place preference (CPP) is a useful model to study the mechanisms involved in stress-induced relapse of drug-seeking behavior. There is evidence that the glutamate NMDA receptors are critically involved in drug- and cue-induced reinstatement of seeking behavior and drug-CPP responses. The aim of this study was to investigate the contribution of NMDA receptors within core vs. shell nucleus accumbens (NAc) subregions to restraint stress-induced reinstatement of extinguished cocaine-CPP. After extinction of cocaine-conditioned preference, animals were administered MK 801 systemically or directly into intra-core or intra-shell, and restrained for 30min or left undisturbed in their home-cages. First, we demonstrated that restraint stress-induced reinstatement of extinguished cocaine-CPP depends on the duration of restraint as well as on the context in which it is applied. Second, this effect was blocked by systemic MK 801 administration either before or after restraint. Third, intra-core but not intra-shell administration abrogated the restraint stress-induced reinstatement. These findings show that NMDA receptors within NAc core, but not shell, play a critical role in restraint stress-induced reinstatement of cocaine-CPP.

Enkephalin is essential for the molecular and behavioral expression of cocaine sensitization.

Behavioral sensitization to cocaine is associated to neuroadaptations that contribute to addiction. Enkephalin is highly expressed in mesocorticolimbic areas associated with cocaine-induced sensitization; however, their influence on cocaine-dependent behavioral and neuronal plasticity has not been explained. In this study, we employed a knockout (KO) model to investigate the contribution of enkephalin in cocaine-induced behavioral sensitization. Wild-type (WT) and proenkephalin KO mice were treated with cocaine once daily for 9 days to induce sensitization. Additionally, to clarify the observations in KO mice, the same procedure was applied in C57BL/6 mice, except that naloxone was administered before each cocaine injection. All animals received a cocaine challenge on days 15 and 21 of the treatment to evaluate the expression of locomotor sensitization. On day 21, microdialysis measures of accumbal extracellular dopamine, Western blotting for GluR1 AMPA receptor (AMPAR), phosphorylated ERK2 (pERK2), CREB (pCREB), TrKB (pTrkB) were performed in brain areas relevant for sensitization from KO and WT and/or naloxone- and vehicle pre-treated animals. We found that KO mice do not develop sensitization to the stimulating properties of cocaine on locomotor activity and on dopamine release in the nucleus accumbens (NAc). Furthermore, pivotal neuroadaptations such as the increase in pTrkB receptor, pERK/CREB and AMPAR related to sensitized responses were absent in the NAc from KO mice. Consistently, full abrogation of cocaine-induced behavioral and neuronal plasticity after naloxone pre-treatment was observed. We show for first time that the proenkephalin system is essential in regulating long-lasting pivotal neuroadaptations in the NAc underlying behavioral sensitization to cocaine.

Participation of catalase in voluntary ethanol consumption in perinatally low-level lead-exposed rats.

BACKGROUND: Environmental lead (Pb) exposure and alcohol abuse pose significant public health problems for our society. One of the proposed mechanisms of action of the developmental neurotoxicant Pb is related to its ability to affect antioxidant enzymes, including catalase (CAT). Ethanol's (EtOH) motivational effects are postulated to be mediated by the CAT-dependent acetaldehyde generated in the brain. The current study sought to investigate the role of this enzyme in the elevated EtOH intake previously reported in perinatally Pb-exposed rats. METHODS: Thirty-five-day-old male Wistar rats exposed to 220 ppm Pb during gestation and lactation were offered escalating EtOH solutions (2 to 10%) or water, 2 h/d for 28 days. Once baseline 10% EtOH intake was achieved, they were injected with (i) saline (SAL), (ii) 3-amino 1,2,4 triazole (aminotriazole [AT], a CAT inhibitor, 250 mg/kg intraperitoneally [i.p.], 5 hours before the last 8 EtOH intake sessions), or (iii) 3-nitropropionic acid (3NPA; a CAT activator, 20 mg/kg subcutaneously [s.c.], 45 minutes before the last 4 EtOH intake sessions). Rats were then sacrificed, blood collected, and brain regions harvested for CAT activity determination. Additional studies evaluated EtOH intake and CAT activity in response to 10 and 30 mg/kg 3NPA. Both 3NPA and AT were evaluated for striatal cytotoxicity. RESULTS: We observed that AT pretreatment blunted the increased EtOH intake, as well as the elevated CAT activity in blood, cerebellum, and hippocampus evidenced in the developmentally Pb-exposed rats that have consumed EtOH. Conversely, 20 mg/kg 3NPA further increased voluntary EtOH intake in these animals as compared with controls, concomitantly with a slight elevation in CAT activity both in blood and in the striatum, associated with no changes in striatal cytotoxicity. CONCLUSIONS: These results suggest a participation of CAT, and possibly acetaldehyde, in Pb-induced high EtOH intake, and open up new avenues to elucidate the mechanism that underlies the Pb and EtOH interaction.

Intoxicación por plomo y su tratamiento farmacológico / Lead poisoning and pharmacological treatment

La intoxicación por plomo es un problema de saludpública. La evidencia de poblaciones afectadas por nivelestóxicos de plomo en sangre, confirma que hay que seguirtrabajando desde una visión pluridisciplinar. Es necesariodefinir políticas para la prevención, detección, diagnosticoy tratamiento de los efectos nocivos del plomo sobre lasalud. Los niños constituyen el segmento de la poblaciónmás vulnerable, con consecuencias de alto impactosocial, como una disminución del coeficiente intelectual ydeficiente desarrollo neurológico. En la práctica clínica, haycuatro medicamentos que se usan para el tratamiento de laintoxicación crónica, son el edetato cálcico disódico IV e IM,el dimercaprol IM, la penicilamina VO y el succímero VO.Si se tiene en cuenta que sólo penicilamina está autorizadaen nuestro país, el problema se torna mayor. Esta breverevisión pretende brindar información sobre la intoxicaciónpor exposición al plomo, los tratamientos recomendados ylos disponibles en nuestro país.(AU)

Lead exposure and poisoning is a public health concern.Evidence of people with toxic level of lead in blood confirmsINTOXICACION PORPLOMO Y SU TRATAMIENTOFARMACOLOGICORecibido: 25 de Setiembrede 2012. Aprobado: 4 denoviembre de 2012Lead poisoning and pharmacological treatmentFontana Daniela,Lascano Valeria María,Solá Nancy,Martinez Samanta,Virgolini Miriam,Mazzieri Maria Rosa.Departamento de Farmacia,Facultad de Ciencias Químicas,Universidad Nacional deCórdoba.Medina Allende y Haya de laTorre, Ciudad Universitaria,(5000) Córdoba, ArgentinaTEL/FAX +54 351 535 3850(int 53351). E-mail: mrmazzie@fcq.unc.edu.ar that it is necessary to keep on working from a multidisciplinary approach. There shouldbe a well-defined policy for the prevention, detection, diagnosis and treatment of theharmful effects of lead. Children are the population at major risk, with high social impactconsequences such as lower IQ and inadequate neurological development. There arefour drugs used to treat chronic toxicity: sodium calcium edetate IV and IM, succimer(oral), dimercaprol IM, and penicillamine (oral). If we consider that the last one is theonly authorized drug in our country, the problem grows bigger. This brief review offersinformation about lead exposure and poisoning, the recommended drug treatments andtheir market availability.(AU)

Intoxicación por plomo y su tratamiento farmacológico / Lead poisoning and pharmacological treatment

La intoxicación por plomo es un problema de saludpública. La evidencia de poblaciones afectadas por nivelestóxicos de plomo en sangre, confirma que hay que seguirtrabajando desde una visión pluridisciplinar. Es necesariodefinir políticas para la prevención, detección, diagnosticoy tratamiento de los efectos nocivos del plomo sobre lasalud. Los niños constituyen el segmento de la poblaciónmás vulnerable, con consecuencias de alto impactosocial, como una disminución del coeficiente intelectual ydeficiente desarrollo neurológico. En la práctica clínica, haycuatro medicamentos que se usan para el tratamiento de laintoxicación crónica, son el edetato cálcico disódico IV e IM,el dimercaprol IM, la penicilamina VO y el succímero VO.Si se tiene en cuenta que sólo penicilamina está autorizadaen nuestro país, el problema se torna mayor. Esta breverevisión pretende brindar información sobre la intoxicaciónpor exposición al plomo, los tratamientos recomendados ylos disponibles en nuestro país.

Lead exposure and poisoning is a public health concern.Evidence of people with toxic level of lead in blood confirmsINTOXICACIÓN PORPLOMO Y SU TRATAMIENTOFARMACOLOGICORecibido: 25 de Setiembrede 2012. Aprobado: 4 denoviembre de 2012Lead poisoning and pharmacological treatmentFontana Daniela,Lascano Valeria María,Solá Nancy,Martinez Samanta,Virgolini Miriam,Mazzieri Maria Rosa.Departamento de Farmacia,Facultad de Ciencias Químicas,Universidad Nacional deCórdoba.Medina Allende y Haya de laTorre, Ciudad Universitaria,(5000) Córdoba, ArgentinaTEL/FAX +54 351 535 3850(int 53351). E-mail: mrmazzie@fcq.unc.edu.ar that it is necessary to keep on working from a multidisciplinary approach. There shouldbe a well-defined policy for the prevention, detection, diagnosis and treatment of theharmful effects of lead. Children are the population at major risk, with high social impactconsequences such as lower IQ and inadequate neurological development. There arefour drugs used to treat chronic toxicity: sodium calcium edetate IV and IM, succimer(oral), dimercaprol IM, and penicillamine (oral). If we consider that the last one is theonly authorized drug in our country, the problem grows bigger. This brief review offersinformation about lead exposure and poisoning, the recommended drug treatments andtheir market availability.