Ricardo Schneider

N-acetylcysteine prevents behavioral and biochemical changes induced by alcohol cessation in rats

N-acetylcysteine (NAC), a glutamate-modulating agent with antioxidant and anti-inflammatory properties, has been considered as a potential anti-addictive drug. Beneficial effects were reported for cocaine, cannabis, and tobacco addicts, but the effect of NAC in alcoholics or in alcohol animal models is unknown. The aggravation of alcohol withdrawal symptoms, such as anxiety, has been associated with increased levels of serum corticosterone and leptin. Thus, the aim of this study was to assess the effects of NAC on anxiety, as well as corticosterone and leptin serum levels, after cessation of chronic alcohol treatment in rats. Male Wistar rats were treated with 2 g/kg ethanol, twice daily, by gavage for 30 days; control animals received an appropriate dose of glucose to balance caloric intake. Rats were treated for 4 days with NAC (60 and 90 mg/kg, intra-peritoneally [i.p.]) or saline after alcohol cessation. Twenty-four hours after the last treatment, rats were exposed to a 5-min session in the open-field test (OF). Corticosterone and leptin serum levels were determined by ELISA in samples collected within 30 min after the OF. Results showed that rats were hypoactive (decreased rearing, peripheral, and total crossings), and that corticosterone and leptin levels were increased 5 days after alcohol cessation. Four days of NAC prevented the behavioral and biochemical changes brought about by alcohol cessation. We suggest that, in addition to the anti-addictive properties reported for other drugs of abuse, NAC is potentially useful in the management of alcohol withdrawal.

Temperament and character traits associated with the use of alcohol, cannabis, cocaine, benzodiazepines, and hallucinogens: evidence from a large Brazilian web survey

OBJECTIVES To evaluate how personality traits are associated with occasional use, abuse, and dependence of alcohol, cannabis, cocaine, benzodiazepines, and hallucinogens in a large availability sample of adults via online questionnaires. METHODS The sample consisted of 8,646 individuals (24.7% men and 75.3% women) who completed an anonymous web survey. Involvement with drugs and temperament/character traits were assessed through the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) and the Temperament and Character Inventory - Revised (TCI-R), respectively. Interactions among variables were analyzed using MANOVA with Bonferroni adjustment. RESULTS Novelty seeking was the trait most associated with increased involvement with alcohol, cannabis, and cocaine. There was a significant association between harm avoidance and benzodiazepine use. Persistence was lower in cannabis-, benzodiazepine-, and cocaine-dependent subjects, as well as in hallucinogen abusers. Self-directedness was reduced in dependents of all drug classes. No strong relationships were found between other temperament or character dimensions and the severity of drug use. CONCLUSIONS Novelty seeking was associated with increased involvement with all drugs studied in this sample, although to a lesser extent with benzodiazepines and hallucinogens. The temperament and character profile for benzodiazepine use was different from that of other drugs due to the relationship with higher harm avoidance and self-transcendence and lower self-directedness.

Lead–germanate glasses: an easy growth process for silver nanoparticles and their promising applications in photonics and catalysis

In this study, we report non-conventional silver nanoparticle growth on the surface of lead–germanate oxide glasses. Thermal annealing at around the glass transition temperature (Tg) under a nitrogen atmosphere enables the growth of silver thin films on the glass surface. The nanoparticle growth was monitored by scanning electron microscopy (SEM) and UV-visible spectroscopy as a function of the annealing time. The characteristic temperatures were obtained by differential thermal analysis (DTA) and the influence of the Ag+ ion content on the glass stability (GS) parameters was evaluated. Additionally, the apparent activation energy of crystallization (E) was calculated. The silver thin films obtained after different annealing times were applied as a substrate for luminescence enhancement of the Eu(btfa)3·bipy rare earth europium complex. The catalytic activity of the Ag-doped glasses was tested for the reduction of p-nitrophenol in the presence of NaBH4. The catalytic performance of the unannealed glass demonstrated an unexpected good efficiency compared with the annealed glass samples.

Effect of Alcohol and Tobacco Smoke on Long-Term Memory and Cell Proliferation in the Hippocampus of Rats

INTRODUCTION Alcohol is frequently used in combination with tobacco and few studies explore interactions between these two drugs of abuse. Here, we evaluated the effect of chronic alcohol administration and concomitant exposure to tobacco smoke on long-term memory and on cell proliferation in the hippocampus of rats. METHODS Forty male Wistar rats were assigned to four groups and treated with alcohol (2g/kg by gavage) and/or exposed to tobacco smoke (from six cigarettes, by inhalation) twice a day (at 9:00 AM and 2:00 PM) for 30 days. Long-term memory was evaluated in the inhibitory avoidance test and hippocampal cell proliferation was analyzed for bromodeoxyuridine immunohistochemistry. RESULTS Our results showed that alcohol, tobacco smoke, or their combination improved the long-term memory evaluated by the memory index in rats. Moreover, alcohol and tobacco coadministration decreased bromodeoxyuridine-labeled cells by 60% when compared to the control group, while alcohol treatment decreased labeled cells by 40%. The tobacco group showed a nonsignificant 26% decrease in labeled cells compared to the control group. CONCLUSIONS Chronic alcohol and tobacco coadministration improves the long-term memory in rats in the inhibitory avoidance test. However, coadministration decreases the cell proliferation in the hippocampus of rats, suggesting a deleterious effect by the combined use of these drugs of abuse.

Antioxidant and hepatoprotective effects of an organic grapevine leaf (Vitis labrusca L.) extract in diabetic rats

Our objective was to investigate the antioxidant effect of an aqueous extract of organic grapevine leaves (Vitis labrusca L.) on the livers of diabetic rats and to evaluate the resulting changes in metabolic and biochemical parameters. Diabetic rats received daily intragastric doses of 50, 100 or 200 mg kg−1 of the grapevine extract for 30 days. Grapevine leaf extract showed a dose-dependent antioxidant effect on the livers of diabetic rats, evidenced by decreases in TBARS and in carbonyl levels and increases in sulfhydryl levels. Moreover, the extract (200 mg kg−1) prevented weight loss and reduced LDL cholesterol (50 mg kg−1), urea (50 mg kg−1), and AST (50 and 100 mg kg−1) levels in diabetic rats at the indicated doses. Thus, we suggest that chronic treatment with an extract of grapevine leaves may represent an adjuvant therapy for the treatment and/or prevention of diabetic complications because of its antioxidant, hepatoprotective and possible hypolipidemic effects shown here.

Taurine restores the exploratory behavior following alcohol withdrawal and decreases BDNF mRNA expression in the frontal cortex of chronic alcohol-treated rats

ABSTRACT Alcohol use disorder is an alarming health problem, and the withdrawal symptoms increase the risk of relapse. We have hypothesized that taurine, a multitarget substance acting as a gamma‐aminobutyric acid A receptor (GABAAR) positive modulator and a partial inhibitor of N‐methyl‐d‐aspartate (NMDA) glutamate receptors, may reduce the withdrawal symptoms or modify behaviors when combined with alcohol. Therefore, we investigated the effects of taurine on behavior in the open field test (OFT), the GABAAR &agr;2 subunit and BDNF mRNA expression in the frontal cortex of rats after chronic alcohol treatment or upon withdrawal. Rats received alcohol 2 g/kg (alcohol and withdrawal groups) or water (control group) twice daily by oral gavage for 28 days. On day 29, the withdrawal rats received water instead of alcohol, and all groups were reallocated to receive 100 mg/kg taurine or vehicle intraperitoneally, once a day for 5 days. On day 33, the rats were exposed to OFT; 18 h later, they were euthanized, and the frontal cortex was dissected for GABAAR &agr;2 subunit detection and BDNF mRNA expression determination by real‐time quantitative PCR. Taurine administration restored rearing behavior to the control levels in the withdrawal rats. Taurine also showed anxiolytic‐like effects in control rats and did not change the behaviors in the chronic alcohol group. Chronic alcohol treatment or withdrawal did not change the GABAAR &agr;2 subunit or BDNF mRNA expression in the frontal cortex, but taurine decreased the &agr;2 subunit level in control rats and to the BDNF levels in the alcohol rat group. We conclude that taurine restored exploratory behavior after alcohol withdrawal but that this effect was not related to the GABAAR &agr;2 subunit or BDNF mRNA expression in the frontal cortex of the rats. HIGHLIGHTSAlcohol withdrawal decreases rearing in rats and taurine treatment reestablishes it.Taurine presents an anxiolytic‐like effect in control rats.Taurine does not affect behaviors in chronically alcohol treated rats.Chronic alcohol or withdrawal does not change GABAAR &agr;2 mRNA in the frontal cortex of rats.Alcohol withdrawal does not change BDNF mRNA in the frontal cortex of rats.

Acute intraperitoneal administration of taurine decreases the glycemia and reduces food intake in type 1 diabetic rats

Taurine, an amino acid with antioxidant and osmoregulatory properties, has been studied for its possible antidiabetic properties in type 1 and type 2 diabetic animals. In type 2 diabetic mice, taurine decreases blood glucose through increased insulin secretion and insulin receptor sensitization. However, insulin is absent in type 1 diabetic individuals. The aim of this study was to evaluate the effects of taurine on parameters related to the energy balance that could explain the metabolic action of this amino acid in type 1 diabetic rats. Control and streptozotocin-induced diabetic rats received saline or taurine (100 mg/kg/day), intraperitoneally, for 30 days. Parameters such as palatable food intake, gastrointestinal transit rate, serum glucose, insulin, leptin, and glucagon levels were measured 60 min after the last taurine administration. Liver, kidneys, heart, and retroperitoneal fat were dissected and weighted. Glycogen levels were measured in the liver and soleus muscle. Our results showed that acute taurine administration decreased glycemia. It also decreased food intake in diabetic rats, without affecting other metabolic parameters. Altogether, our results suggest that in type 1 diabetic rats, taurine decreases blood glucose by a non-insulin-dependent mechanism. Due to the safety profile of taurine, and its effect on glycemia, this amino acid may help to design new drugs to add benefit to insulin therapy in type 1 diabetic individuals.