RESUMO
Contaminants of emerging concern (CECs) are released daily into surface water, and their recalcitrant properties often require tertiary treatment. Electrochemical oxidation (EO) is often used as an alternative way to eliminate these compounds from water, although the literature barely addresses the neurotoxic effects of residual by-products. Therefore, this study investigated the performance of EO in the removal of five CECs (alprazolam, clonazepam, diazepam, lorazepam, and carbamazepine) and performed neurotoxicity evaluations of residual EO by-products in Wistar rat brain hippocampal slices. Platinum-coated titanium (Ti/Pt) and boron-doped diamond (BDD) electrodes were studied as anodes. Different current densities (13-75 A m-2), pH values (3-10), electrolyte dosages (NaCl), and matrix effects were assessed using municipal wastewater (MWW). The drugs were successfully degraded after 5 min of reaction for both the Ti/Pt and BDD electrodes when a current density of 75 A m-2 was applied. For Ti/Pt and BDD, neutral and acidic pH demonstrated better CEC removal performance, respectively. Compound degradation using MWW achieved 40% removal after 120 min for Ti/Pt and ranged between 33 and 52% for the BDD anode. For Ti/Pt, neurotoxicity studies using MWW indicated a decrease in reactive oxygen species (ROS) signals. However, when an artificial cerebrospinal fluid (ACSF) medium was reapplied, the signal recovered and increased to a value above the baseline, indicating that cells recovered part of their normal activity but remained in a different condition. For the BDD anode, the treated MWW did not cause significant ROS production variations, suggesting that he EO was effective in eliminating the toxicity of the treated solution.
Assuntos
Preparações Farmacêuticas , Poluentes Químicos da Água , Animais , Diamante , Eletrodos , Oxirredução , Ratos , Ratos Wistar , Águas Residuárias , Poluentes Químicos da Água/análiseRESUMO
Lead is a heavy metal of high impact for the environment as well as for human health, being cause of several diseases. Considering the importance of obtaining an effective treatment for lead removal, a new hybrid material was developed for sorption of Pb2+ from aqueous solution. The effect of pH, temperature, liquid/solid ratio (g/cm3) and lead concentration on the sorption capacity of yeasts chemically modified with cubic silsesquioxane (YS) was analyzed. Additionally, the toxicity of lead on the neuronal activity was also investigated in order to assess whether the damage caused by the Pb2+ ion is reversible or not. The YS is highly promissory as sorbent of lead in high concentrations (100 and 500ppm), reaching high efficiency in short contact times (15min), and at the natural pH (4) of the Pb2+ solution and room temperature. The best sorption obtained was 82% removal and 248mg/g with 500cm3/g sorbent, pH 4, room temperature and contact time of 15min. Besides, such high efficiencies are obtained with low quantities of biosorbent, when compared with other similar materials. The impact of lead on neuronal function was studied by measuring autofluorescence signals, associated with changes in cellular metabolism, at the hippocampal CA3 area in brain slices. In this toxicity tests, the effect of low concentrations of lead (1 and 3µM) on neuronal activity was evaluated. After removal of the lead, the irreversibility of the observed changes can be verified, which suggests the existence of neuronal damages.
Assuntos
Chumbo/metabolismo , Chumbo/toxicidade , Compostos de Organossilício/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/metabolismo , Animais , Região CA3 Hipocampal/química , Região CA3 Hipocampal/efeitos dos fármacos , Feminino , Histocitoquímica , Ratos , Ratos WistarRESUMO
BACKGROUND: The hippocampal CA3 area contains large amounts of vesicular zinc in the mossy fiber terminals which is released during synaptic activity, depending on presynaptic calcium. Another characteristic of these synapses is the presynaptic localization of high concentrations of group II metabotropic glutamate receptors, specifically activated by DCG-IV. Previous work has shown that DCG-IV affects only mossy fiber-evoked responses but not the signals from associational-commissural afferents, blocking mossy fiber synaptic transmission. Since zinc is released from mossy fibers even for single stimuli and it is generally assumed to be co-released with glutamate, the aim of the work was to investigate the effect of DCG-IV on mossy fiber zinc signals. RESULTS: Studies were performed using the membrane-permeant fluorescent zinc probe TSQ, and indicate that DCG-IV almost completely abolishes mossy fiber zinc changes as it does with synaptic transmission. CONCLUSIONS: Zinc signaling is regulated by the activation of type II metabotropic receptors, as it has been previously shown for glutamate, further supporting the corelease of glutamate and zinc from mossy fibers.
Assuntos
Anticonvulsivantes/farmacologia , Ciclopropanos/farmacologia , Glicina/análogos & derivados , Fibras Musgosas Hipocampais/efeitos dos fármacos , Receptores de Glutamato Metabotrópico/metabolismo , Zinco/metabolismo , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Animais , Antagonistas de Aminoácidos Excitatórios/farmacologia , Ácido Glutâmico/metabolismo , Glicina/farmacologia , Hipocampo/efeitos dos fármacos , Fibras Musgosas Hipocampais/metabolismo , Terminações Pré-Sinápticas/efeitos dos fármacos , Terminações Pré-Sinápticas/metabolismo , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Estatísticas não Paramétricas , Transmissão Sináptica/efeitos dos fármacos , Vesículas Sinápticas/efeitos dos fármacos , Vesículas Sinápticas/metabolismoRESUMO
BACKGROUND: The hippocampal CA3 area contains large amounts of vesicular zinc in the mossy fiber terminals which is released during synaptic activity, depending on presynaptic calcium. Another characteristic of these synapses is the presynaptic localization of high concentrations of group II metabotropic glutamate receptors, specifically activated by DCG-IV. Previous work has shown that DCG-IV affects only mossy fiber-evoked responses but not the signals from associational-commissural afferents, blocking mossy fiber synaptic transmission. Since zinc is released from mossy fibers even for single stimuli and it is generally assumed to be co-released with glutamate, the aim of the work was to investigate the effect of DCG-IV on mossy fiber zinc signals. RESULTS: Studies were performed using the membrane-permeant fluorescent zinc probe TSQ, and indicate that DCG-IV almost completely abolishes mossy fiber zinc changes as it does with synaptic transmission. CONCLUSIONS: Zinc signaling is regulated by the activation of type II metabotropic receptors, as it has been previously shown for glutamate, further supporting the corelease of glutamate and zinc from mossy fibers.