The effect of perinatal lead exposure on dopamine receptor D2 expression in morphine dependent rats

The Influence of Topiramate on Morphine Dependence in Mice

Topiramate evokes pharmacological activity via a blockade of voltage-dependent sodium channels, reduction in glutamate release, inhibition of AMPA receptors and kainate receptors, and potentiation of GABAergic neurotransmission. Therefore, it is used not only as an antiseizure drug but is also effective in migraine prophylaxis, cluster headaches, neuropathic pain, and alcohol dependence. The aim of this study was to investigate the effect of topiramate in morphine dependence in mice, particularly in terms of morphine tolerance, morphine withdrawal signs, and morphine sensitization. In these experiments, topiramate was administered both acutely and chronically. Topiramate significantly reduced the morphine tolerance in the hot-plate test and attenuated naloxone-induced morphine withdrawal signs. Its effect on morphine sensitization to the locomotor activity of mice was poor. The obtained results showed that topiramate might be an effective drug for reducing the physical symptoms of morphine dependence.

Molecular and Environmental Determinants of Addictive Substances

Knowledge about determinants of addiction in people taking addictive substances is poor and needs to be supplemented. The novelty of this paper consists in the analysis of innovative aspects of current research about relationships between determinants of addiction in Polish patients taking addictive substances and rare available data regarding the relationships between these factors from studies from recent years from other environments, mainly in Europe, and on the development of genetic determinants of physiological responses. We try to explain the role of the microelements Mn, Fe, Cu, Co, Zn, Cr, Ni, Tl, Se, Al, B, Mo, V, Sn, Sb, Ag, Sr, and Ba, the toxic metals Cd, Hg, As, and Pb, and the rare earth elements Sc, La, Ce, Pr, Eu, Gd, and Nd as factors that may shape the development of addiction to addictive substances or drugs. The interactions between factors (gene polymorphism, especially ANKK1 (TaqI A), ANKK1 (Taq1 A-CT), DRD2 (TaqI B, DRD2 Taq1 B-GA, DRD2 Taq1 B-AA, DRD2-141C Ins/Del), and OPRM1 (A118G)) in patients addicted to addictive substances and consumption of vegetables, consumption of dairy products, exposure to harmful factors, and their relationships with physiological responses, which confirm the importance of internal factors as determinants of addiction, are analyzed, taking into account gender and region. The innovation of this review is to show that the homozygous TT mutant of the ANKK1 TaqI A polymorphism rs 1800497 may be a factor in increased risk of opioid dependence. We identify a variation in the functioning of the immune system in addicted patients from different environments as a result of the interaction of polymorphisms.

Molecular mechanisms of morphine tolerance and dependence; novel insights and future perspectives

Drug addiction is a devastating condition that poses a serious burden on the society. The use of some drugs like morphine for their tremendous analgesic properties is also accompanied with developing tolerance, dependence and the withdrawal symptoms. These symptoms are frequently severe enough to reinforce the person in recovery to start over the use of drug again and hinder the clinical use of drugs like morphine for chronic pain. Research into opioid receptors and related molecular pathways has seen resurgence in the wake of the growing opioid epidemic. The current study provides a comprehensive scientific exploration of the molecular mechanisms and underlying signalling in morphine tolerance and dependence. It also critically evaluates current therapeutic approaches, shedding light on their efficacy and limitations, and future prospects.

The Effect of Prenatal and Neonatal Fluoride Exposure to Morphine-Induced Neuroinflammation

Physical dependence is associated with the formation of neuroadaptive changes in the central nervous system (CNS), both at the molecular and cellular levels. Various studies have demonstrated the immunomodulatory and proinflammatory properties of morphine. The resulting neuroinflammation in drug dependence exacerbates substance abuse-related behaviors and increases morphine tolerance. Studies prove that fluoride exposure may also contribute to the development of neuroinflammation and neurodegenerative changes. Morphine addiction is a major social problem. Neuroinflammation increases tolerance to morphine, and neurodegenerative effects caused by fluoride in structures related to the development of dependence may impair the functioning of neuronal pathways, change the concentration of neurotransmitters, and cause memory and learning disorders, which implies this element influences the development of dependence. Therefore, our study aimed to evaluate the inflammatory state of selected brain structures in morphine-dependent rats pre-exposed to fluoride, including changes in cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) expression as well as microglial and astroglial activity via the evaluation of Iba1 and GFAP expression. We provide evidence that both morphine administration and fluoride exposure have an impact on the inflammatory response by altering the expression of COX-1, COX-2, ionized calcium-binding adapter molecule (Iba1), and glial fibrillary acidic protein (GFAP) in brain structures involved in dependence development, such as the prefrontal cortex, striatum, hippocampus, and cerebellum. We observed that the expression of COX-1 and COX-2 in morphine-dependent rats is influenced by prior fluoride exposure, and these changes vary depending on the specific brain region. Additionally, we observed active astrogliosis, as indicated by increased GFAP expression, in all brain structures of morphine-dependent rats, regardless of fluoride exposure. Furthermore, the effect of morphine on Iba1 expression varied across different brain regions, and fluoride pre-exposure may influence microglial activation. However, it remains unclear whether these changes are a result of the direct or indirect actions of morphine and fluoride on the factors analyzed.

Early-life low-level lead exposure alters anxiety-like behavior, voluntary alcohol consumption and AC5 protein content in adult male and female C57BL/6 J mice

Despite efforts to eradicate sources of environmental lead (Pb), children, predominately in lower socioeconomic areas, are still frequently exposed to unsafe levels of Pb from soils, dust, and water. Human studies suggest that Pb exposure is associated with altered drug consumption in adults; however, there is limited research at comparable exposure levels (blood Pb levels <10 μg/dL). To model how early-life, low-level Pb exposure affects alcohol consumption in adulthood, we exposed postnatal day (PND) 21 C57Bl/6 J mice to either 30 ppm or 0 ppm Lead (IV) Acetate in distilled water until PND 42, and testing began in adulthood. We predicted that mice with early-life Pb exposure would exhibit greater anxiety-like behavior and consume more alcohol in a three-week Drinking-in-the-Dark procedure (20% v/v) and a 24-h two-bottle choice procedure (10% v/v). We also predicted that Pb exposure would decrease whole-brain content of Adenylate Cyclase-5 (AC5), a protein linked to anxiety-like behaviors and alcohol drinking. There was no difference in limited-access binge-like consumption between exposure groups; however, Pb-exposed mice displayed higher two-bottle choice alcohol intake and preference. Furthermore, Pb-exposed mice exhibited greater anxiety-like behaviors in experiments conducted before an alcohol drinking history but not after. Finally, Pb-exposed mice exhibited an upregulation of whole-brain AC5 protein content. However, this difference was not found in the nucleus accumbens, dorsomedial or dorsolateral striatum. These findings conclude that early-life Pb exposure alters voluntary alcohol consumption and whole-brain AC5 protein content in adulthood. Future studies are necessary to further understand the mechanism behind how Pb exposure alters alcohol intake.

Central Effects of the Designer Drug Mephedrone in Mice-Basic Studies

Mephedrone belongs to the "party drugs" thanks to its psychostimulant effects, similar to the ones observed after amphetamines. Though mephedrone is used worldwide by humans and in laboratory animals, not all properties of this drug have been discovered yet. Therefore, the main aim of this study was to expand the knowledge about mephedrone's activity in living organisms. A set of behavioral tests (i.e., measurement of the spontaneous locomotor activity, rotarod, chimney, elevated plus maze with its modification, novel object recognition, and pentylenetetrazol seizure tests) were carried out in male albino Swiss mice. Different dose ranges of mephedrone (0.05-5 mg/kg) were administered. We demonstrated that mephedrone at a dose of 5 mg/kg rapidly increased the spontaneous locomotor activity of the tested mice and its repeated administration led to the development of tolerance to these effects. Mephedrone showed the anxiolytic-like potential and improved spatial memory, but it did not affect recognition memory. Moreover, the drug seemed not to have any anticonvulsant or proconvulsant activity. In conclusion, mephedrone induces many central effects. It easily crosses the blood-brain barrier and peaks in the brain quickly after exposure. Our experiment on inducing a hyperlocomotion effect showed that mephedrone's effects are transient and lasted for a relatively short time.

The Effect of Lead Exposure on Autism Development

Autism Spectrum Disorder (ASD) remains one of the most detrimental neurodevelopmental conditions in society today. Common symptoms include diminished social and communication ability. Investigations on autism etiology remain largely ambiguous. Previous studies have highlighted exposure to lead (Pb) may play a role in ASD. In addition, lead has been shown to be one of the most prevalent metal exposures associated with neurological deficits. A semi-systematic review was conducted using public databases in order to evaluate the extent of lead's role in the etiology of autism. This review examines the relationship between autistic comorbid symptoms-such as deterioration in intelligence scores, memory, language ability, and social interaction-and lead exposure. Specifically, the mechanisms of action of lead exposure, including changes within the cholinergic, dopaminergic, glutamatergic, gamma aminobutyric acid (GABA)ergic systems, are discussed. The goal of this review is to help illustrate the connections between lead's mechanistic interference and the possible furthering of the comorbidities of ASD. Considerations of the current data and trends suggest a potential strong role for lead in ASD.

Morphine-element interactions - The influence of selected chemical elements on neural pathways associated with addiction

Addiction is a pressing social problem worldwide and opioid dependence can be considered the strongest and most difficult addiction to treat. Mesolimbic and mesocortical dopaminergic pathways play an important role in modulation of cognitive processes and decision making and, therefore, changes in dopamine metabolism are considered the central basis for the development of dependence. Disturbances caused by excesses or deficiency of certain elements have a significant impact on the functioning of the central nervous system (CNS) both in physiological conditions and in pathology and can affect the cerebral reward system and therefore, may modulate processes associated with the development of addiction. In this paper we review the mechanisms of interactions between morphine and zinc, manganese, chromium, cadmium, lead, fluoride, their impact on neural pathways associated with addiction, and on antinociception and morphine tolerance and dependence.

Depression, changes in peripheral blood cell count, and changes in selected biochemical parameters related to lead concentration in whole blood (Pb-B) of women in the menopausal period

THE AIM

The aim of this study was to assess the severity of depression, vasomotor symptoms, changes in peripheral blood cell count, and selected biochemical parameters in relation to the concentration of lead in whole blood of women in the perimenopausal period.

METHODS

The study sample consisted of 233 women from the general population of the West Pomeranian Province (Poland) in age between 44-65 years. The intensity of menopausal symptoms was examined using the Blatt-Kupperman Index, and the severity of depression using the Beck Depression Inventory. The following biochemical data were evaluated: concentrations of glucose, triglycerides, HDL, C-reactive protein, glycated haemoglobin, cortisol, insulin, blood cell count, and lead concentration in whole blood (Pb-B).

RESULTS

A whole blood Pb concentration below 5 μg/dl was found in 55 subjects (23.61 %), in 142 women (60.94 %) it ranged from 5 to 10 μg/dl, while in 36 women (15.45 %) was higher than 10 μg/dl. There was a strong positive correlation between Pb concentration in the blood of the examined women and the severity of depressive symptoms (Rs=+0.60, p = 0.001). The lowest mean values for total leukocytes (5.07 ± 1.22 thousand/μl) and neutrophils (2.76 ± 0.86 thousand/μl) were found in women with Pb concentration above 10 μg/dl (p < 0.05). There was a significant negative correlation between the number of total leukocytes (r=-0.45, p = 0.002) and neutrophils (r=-0.50, p = 0.001) and blood Pb concentration. Analysis showed statistically significant differences in glucose concentration (p < 0.05) between groups. Blood glucose was higher in women with Pb-B <5 and between 5-10 μg/dl than in women with Pb-B >10 μg/dl.

CONCLUSION

Exposure to Pb may be a factor playing a significant role in the development of depressive symptoms in menopausal women. It may also be associated with glucose metabolism disorders and immunosuppression in women during this period of life.

Pre- and Neonatal Exposure to Lead (Pb) Induces Neuroinflammation in the Forebrain Cortex, Hippocampus and Cerebellum of Rat Pups

Lead (Pb) is a heavy metal with a proven neurotoxic effect. Exposure is particularly dangerous to the developing brain in the pre- and neonatal periods. One postulated mechanism of its neurotoxicity is induction of inflammation. This study analyzed the effect of exposure of rat pups to Pb during periods of brain development on the concentrations of selected cytokines and prostanoids in the forebrain cortex, hippocampus and cerebellum. Methods: Administration of 0.1% lead acetate (PbAc) in drinking water ad libitum, from the first day of gestation to postnatal day 21, resulted in blood Pb in rat pups reaching levels below the threshold considered safe for humans by the Centers for Disease Control and Prevention (10 µg/dL). Enzyme-linked immunosorbent assay (ELISA) method was used to determine the levels of interleukins IL-1β, IL-6, transforming growth factor-β (TGF-β), prostaglandin E2 (PGE2) and thromboxane B2 (TXB2). Western blot and quantitative real-time PCR were used to determine the expression levels of cyclooxygenases COX-1 and COX-2. Finally, Western blot was used to determine the level of nuclear factor kappa B (NF-κB). Results: In all studied brain structures (forebrain cortex, hippocampus and cerebellum), the administration of Pb caused a significant increase in all studied cytokines and prostanoids (IL-1β, IL-6, TGF-β, PGE2 and TXB2). The protein and mRNA expression of COX-1 and COX-2 increased in all studied brain structures, as did NF-κB expression. Conclusions: Chronic pre- and neonatal exposure to Pb induces neuroinflammation in the forebrain cortex, hippocampus and cerebellum of rat pups.

The Mechanisms Involved in Morphine Addiction: An Overview

Opioid use disorder is classified as a chronic recurrent disease of the central nervous system (CNS) which leads to personality disorders, co-morbidities and premature death. It develops as a result of long-term administration of various abused substances, along with morphine. The pharmacological action of morphine is associated with its stimulation of opioid receptors. Opioid receptors are a group of G protein-coupled receptors and activation of these receptors by ligands induces significant molecular changes inside the cell, such as an inhibition of adenylate cyclase activity, activation of potassium channels and reductions of calcium conductance. Recent data indicate that other signalling pathways also may be involved in morphine activity. Among these are phospholipase C, mitogen-activated kinases (MAP kinases) or β-arrestin. The present review focuses on major mechanisms which currently are considered as essential in morphine activity and dependence and may be important for further studies.

Neurotoxicity of low-level lead exposure: History, mechanisms of action, and behavioral effects in humans and preclinical models

Lead is a neurotoxin that produces long-term, perhaps irreversible, effects on health and well-being. This article summarizes clinical and preclinical studies that have employed a variety of research techniques to examine the neurotoxic effects of low levels of lead exposure. A historical perspective is presented, followed by an overview of studies that examined behavioral and cognitive outcomes. In addition, a short summary of potential mechanisms of action is provided with a focus on calcium-dependent processes. The current level of concern, or reference level, set by the CDC is 5 μg/dL of lead in blood and a revision to 3.5 μg/dL has been suggested. However, levels of lead below 3 μg/dL have been shown to produce diminished cognitive function and maladaptive behavior in humans and animal models. Because much of the research has focused on higher concentrations of lead, work on low concentrations is needed to better understand the neurobehavioral effects and mechanisms of action of this neurotoxic metal.

Algorithm for establishing the time of death of a dog based on temperature measurements in selected sites of the body during the early post-mortem period

Post-mortem measurements were made of the body temperature of dogs. The aim of the study was to evaluate and verify a reliable mathematical model that can be used to establish the time elapsed since the death of a dog during the initial post-mortem period at room temperature, using the eye (vitreous body), internal organs (heart, liver, kidney and lung), and rectum as sites for temperature measurement. The measurements were performed at six points in the body using an electronic thermometer in conjunction with a temperature probe. The method of temperature measurement is simple and does not cause perceptible macroscopic changes or disfigure the carcass. Multiple regression analysis was shown to be suitable for estimating the time elapsed from death to the discovery of the body for a period up to 12h post-mortem. The proposed multiple regression equation using body weight and the temperature at a specific site reduces manipulation of the carcass to a minimum and thus reduces error in establishing the time of death. The multiple regression model makes it possible to precisely estimate the time elapsed since the death of the animal.

Effects of NMDA antagonists on the development and expression of tolerance to diazepam-induced motor impairment in mice

The goal of the study was to investigate the effects of ketamine and memantine on the development and expression of tolerance to diazepam (DZ)-induced motor impairment in mice. DZ-induced motor incoordination was assessed by the rotarod and chimney tests. It was found that (a) ketamine, at the dose of 5mg/kg (but not 2.5mg/kg), decreased the expression, but not the development, of tolerance to the motor impairing effects of DZ, (b) memantine, at the doses of 5 and 10mg/kg decreased both the development and expression of DZ tolerance in the rotarod test (also in the chimney test but at the higher dose of 10mg/kg) and (c) ketamine and memantine alone had no effect, either in the rotarod or the chimney test in mice. Those findings provided behavioral evidence that the glutamatergic system could contribute an important role in the development and/or expression of tolerance to DZ in mice.

Assessment of association between the dopamine D2 receptor (DRD2) polymorphism and neurodevelopment of children exposed to lead

The mechanism of lead (Pb) neurotoxicity has not been illustrated over the years. People pay more attention to dopaminergic neurotransmission, specifically dopamine receptor-2 (DRD2) Taq IA polymorphism, but no consensus has been reached. A total of 258 three-year-old children in Guiyu (exposed group) and Nanao (reference group), China were examined and their concentrations of blood lead (BPb) were determined. Cognitive and language scores of children were assessed using the Bayley Scales of Infant Development, third edition (BSID-III). Genotyping for the DRD2 polymorphism was carried out using a polymerase chain reaction (PCR) re-sequencing platform. The logistic stepwise regression analysis and stepwise regression analysis was used to explore associations among lead, neurodevelopment of children, and DRD2 Taq IA categories. Median values of Pb in Guiyu was higher than that of the reference group (11.30 ± 5.38 μg/dL vs. 5.77 ± 2.51 μg/dL, P < 0.001). Compared with the reference group, children from e-waste exposed area have lower cognitive scale scores (100 ± 25 vs 120 ± 20, P < 0.001) and lower language scale scores (99.87 ± 7.52 vs 111.39 ± 7.02, P < 0.001). The three kinds of genotype, A1/A1, A1/A2, and A2/A2, had no significant influences on BPb, cognitive scores and language scores (P > 0.05). Exposure of inhabitants, especially children to Pb from informal e-waste recycling activities might have contributed to higher levels of BPb and reduced cognitive and language scores observed in local children, however, the result obtained showed no significant association between DRD2 polymorphism and neurodevelopment of children exposed to lead.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Arsenic exposure in drinking water alters the dopamine system in the brains of C57BL/6 mice

Although exposure to arsenic (As) induces neurotoxic changes, there is a lack of data regarding its specific effects on neurotransmission, particularly dopaminergic neurotransmission. In this study, the dopamine content and expression of tyrosine hydroxylase (TH) and dopamine receptors (DRs) were examined in the striatum and cerebral cortex of the mouse brain following the administration of As (1-100 mg/L NaAsO2 in drinking water). After 3 weeks, significantly decreased TH expression and dopamine content, both in the striatum and the cerebral cortex of mice treated with 100 mg/L As, were observed when compared with controls. Although DR expression was similar in the cerebral cortex of As-treated mice, DRD1 to DRD4 expression significantly increased in the striatum of 100 mg/L As-exposed mice. These data indicate that altered dopaminergic neurotransmission may contribute to As-induced neurotoxic effects.