Effects of dichlorobenzene on acetylcholine receptors in human neuroblastoma SH-SY5Y cells

Effects of Hericium erinaceus Mycelium Extracts on the Functional Activity of Purinoceptors and Neuropathic Pain in Mice with L5 Spinal Nerve Ligation

Neuropathic pain is a serious clinical problem that is difficult to treat. Purinoceptors (P2Rs) transduce pain perception from the peripheral to the central nervous system and play an important role in the transmission of neuropathic pain signals. We previously found that the crude extracts of Hericium erinaceus mycelium (HE-CE) inhibited P2R-mediated signaling in cells and reduced heat-induced pain in mice. The present study explored the effects of HE-CE on neuropathic pain. We used adenosine triphosphate (ATP) as a P2R agonist to generate Ca²⁺ signaling and neuronal damage in a cell line. We also established a neuropathic mouse model of L5 spinal nerve ligation (L5-SNL) to examine neuropathic pain and neuroinflammation. Neuropathic pain was recorded using the von Frey test. Neuroinflammation was evaluated based on immunohistofluorescence observation of glial fibrillary acidic protein (GFAP) levels in astrocytes, ionized calcium-binding adaptor molecule1 (iba1) levels in microglia, and IL-6 levels in plasma. The results show that HE-CE and erinacine-S, but not erinacine-A, totally counteracted Ca²⁺ signaling and cytotoxic effects upon P2R stimulation by ATP in human osteosarcoma HOS cells and human neuroblastoma SH-SY5Y cells, respectively. SNL induced a decrease in the withdrawal pressure of the ipsilateral hind paw, indicating neuropathic pain. It also raised the GFAP level in astrocytes, the iba1 level in microglia, and the IL-6 level in plasma, indicating neuroinflammation. HE-CE significantly counteracted the SNL-induced decrease in withdrawal pressure, illustrating that it could relieve neuropathic pain. It also reduced SNL-induced increases in astrocyte GFAP levels, microglial iba1 levels, and plasma IL-6 levels, suggesting that HE-CE reduces neuroinflammation. Erinacine-S relieved neuropathic pain better than HE-CE. The present study demonstrated that HE inhibits P2R and, thus, that it can relieve neuropathic pain and neuroinflammation.

1,2-Dichlorobenzene affects the formation of the phosphoenzyme stage during the catalytic cycle of the Ca(2+)-ATPase from sarcoplasmic reticulum

BACKGROUND

1,2-Dichlorobenzene (1,2-DCB) is a benzene-derived molecule with two Cl atoms that is commonly utilized in the synthesis of pesticides. 1,2-DCB can be absorbed by living creatures and its effects on naturally-occurring enzymatic systems, including the effects on Ca(2+)-ATPases, have been poorly studied. Therefore, we aimed to study the effect of 1,2-DCB on the Ca(2+)-ATPase from sarcoplasmic reticulum (SERCA), a critical regulator of intracellular Ca(2+) concentration.

RESULTS

Concentrations of 0.05-0.2 mM of 1,2-DCB were able to stimulate the hydrolytic activity of SERCA in a medium-containing Ca(2+)-ionophore. At higher concentrations (0.25-0.75 mM), 1,2-DCB inhibited the ATP hydrolysis to ~80 %. Moreover, ATP hydrolysis and Ca(2+) uptake in a medium supported by K-oxalate showed that starting at 0.05 mM,1,2-DCB was able to uncouple the ratio of hydrolysis/Ca(2+) transported. The effect of this compound on the integrity of the SR membrane loaded with Ca(2+) remained unaffected. Finally, the analysis of phosphorylation of SERCA by [γ-(32)P]ATP, starting under different conditions at 0° or 25 °C showed a reduction in the phosphoenzyme levels by 1,2-DCB, mostly at 0 °C.

CONCLUSIONS

The temperature-dependent decreased levels of phosphoenzyme by 1,2-DCB could be due to the acceleration of the dephosphorylation mechanism - E2P · Ca2 state to E2 and Pi, which explains the uncoupling of the ATP hydrolysis from the Ca(2+) transport.

Theoretical investigations on direct photolysis mechanisms of polychlorinated diphenyl ethers

Polychlorinated diphenyl ethers (PCDEs) are a focus of current environmental concern as a group of ubiquitous potential persistent organic pollutants. There are still significant gaps in our knowledge concerning the photolysis mechanisms of PCDEs. In this study, the direct photolysis mechanisms of PCDEs were investigated by density functional theory. The direct photolysis of PCDEs has three potential reaction pathways including photodechlorination, C-O bond photodissociation, and PCDFs formation. Taking a representative PCDE (i.e., CDE8) for example, we found that C-Cl bond dissociation is the rate-determining step for the photodechlorination. Chlorobenzene is predicted to be photoproduct of CDE8 through the photodissociation of the C-O bond. Furthermore, the calculated mean bond dissociation energies of both C-Cl and C-O bonds of 20 PCDEs decrease with the increased degree of chlorination. It is also found that the photoactivity of PCDEs increases with an increase of chlorination degree by evaluating the average charge of Cl atoms and mean bond dissociation energies of C-Cl and C-O bonds from reaction thermodynamics. Our findings provided a new insight into the mechanisms of direct photolysis of PCDEs, which may be useful in the future in utilizing quantum chemistry calculation in investigating the behavior and fate of organic pollutants in the environment.

Para-dichlorobenzene toxicity - a review of potential neurotoxic manifestations

BACKGROUND

Para-dichlorobenzene (PDCB) is an active ingredient of mothballs, deodorizers and fumigants. Due to the easy availability of this chemical, there is a considerable risk for accidental or intentional toxic exposure. Recently, multiple cases of PDCB toxicity due to mothball ingestion were reported. PDCB toxicity can affect multiple organ systems including liver, kidneys, skin, lung and the central nervous system (CNS). CNS toxicity often results in leukoencephalopathy and heterogeneous neurological manifestations.

OBJECTIVES

The objective of this study was to illustrate the clinical presentation, imaging findings, diagnosis and management of PDCB toxicity.

METHODS

We carried out a literature review of the pharmacological and toxicological properties of PDCB.

CONCLUSIONS

PDCB and other aromatic hydrocarbons are capable of CNS tissue damage and in promoting functional neurological decline. While very little is currently known about prevalence of PDCB addiction, it cannot be ruled out that its illicit use among young people is under-recognized. The number of cases of PDCB toxicity might also rise due to the increasing industrial and domestic use of this chemical.

The relationships between pesticide metabolites and neurobehavioral test performance in the third National Health and Nutrition Examination Survey

Regression analysis was used to estimate and test for relationships between urinary pesticide metabolites and neurobehavioral test performance in adults, 20 to 59 years old, participating in the third National Health and Nutrition Examination Survey. The 12 pesticide metabolites included 2 naphthols, 8 phenols, a phenoxyacetic acid, and a pyridinol. The 3 neurobehavioral tests included in the survey were simple reaction time, symbol-digit substitution, and serial digit learning. As the 2,4-dichlorophenol, 2,5-dichlorophenol, and the pentachlorophenol concentrations increased, performance on the serial digit learning test improved. As the 2,5-dichlorophenol concentration increased, performance on the symbol-digit substitution test improved. At low concentrations, the parent compounds of these metabolites may act at acetylcholine and γ-aminobutyric acid synapses in the central nervous system to improve neurobehavioral test performance.

From smoking to cancers: novel targets to neuronal nicotinic acetylcholine receptors

Cigarette smoking bears a strong etiological association with many neovascularization-related diseases, including cancer, cardiovascular disease, and age-related macular degeneration. Cigarette smoke is a complex mixture of many compounds, including nicotine, which is the major active and addictive component of tobacco. Nicotine and its specific metabolized carcinogens directly bind to nicotinic acetylcholine receptors (nAChRs) on cell membranes and trigger the nAChR signal cascade. The nAChRs were originally thought to be ligand-gated ion channels that modulate physiological processes ranging from neurotransmission to cancer signaling. For several decades, the nAChRs served as a prototypic molecule for neurotransmitter receptors; however, they are now important therapeutic targets for various diseases, including Alzheimer's and Parkinson's diseases, schizophrenia, and even cancer. This paper describes recent advances in our understanding of the assembly, activity, and biological functions of nicotinic receptors, as well as developments in the therapeutic application of nicotinic receptor ligands.

Metabolic profiles in serum of mouse after chronic exposure to drinking water

The toxicity of Nanjing drinking water on mouse (Mus musculus) was detected by 1H nuclear magnetic resonance (NMR)-based metabonomic method. Three groups of mice were fed with drinking water (produced by Nanjing BHK Water Plant), 3.8 μg/L benzo(a)pyrene as contrast, and clean water as control, respectively, for 90 days. It was observed that the levels of lactate, alanine, and creatinine in the mice fed with drinking water were increased and that of valine was decreased. The mice of drinking water group were successfully separated from control. The total concentrations of polycyclic aromatic hydrocarbons (PAHs), phthalates (PAEs), and other organic pollutants in the drinking water were 0.23 μg/L, 4.57 μg/L, and 0.34 μg/L, respectively. In this study, Nanjing drinking water was found to induce distinct perturbations of metabolic profiles on mouse including disorders of glucose-alanine cycle, branched-chain amino acid and energy metabolism, and dysfunction of kidney. This study suggests that metabonomic method is feasible and sensitive to evaluate potential toxic effects of drinking water.