Comparative pharmacological evaluation of the cathinone derivatives, mephedrone and methedrone, in mice.

Mephedrone and methedrone are cathinone-related compounds, which act as non-selective substrates for monoamine transporters, facilitating a neurotransmitter release. We compared the acute pharmacological effects of mephedrone and methedrone, attempting to further evaluate the action mechanisms of methedrone by responsibly and ethically using mice under approved procedures. The effects of both compounds were examined from 10 to 60 min, in a series of behavioral paradigms, namely open-field, plus-maze, hot-plate and tail suspension tests, whereas neurotransmitter brain tissue levels were determined ex vivo by HPLC. Separate groups were pre-treated with the dopamine (DA) antagonist haloperidol, or the serotonin (5-HT) synthesis inhibitor ρCPA, to further assess the mechanisms underlying methedrone effects. The compounds caused marked hyperlocomotion, displaying dissimilar stereotyped behavior, in an open-field arena. Mephedrone caused anxiolytic-like effects, while methedrone induced anxiogenic-like actions in the elevated plus-maze. Both compounds displayed thermal antinociception, with a reduced immobility time in the tail suspension model. Mephedrone triggered a 2- and 3-fold increment of dopamine and serotonin tissue levels, respectively, in the nucleus accumbens, with a 1.5-fold elevation of tissue dopamine in the frontal cortex. Methedrone caused a 2-fold increment of tissue dopamine in the nucleus accumbens and in the striatum, and a 1.5-fold increment of serotonin tissue levels in the hippocampus and striatum. In vivo methedrone effects were partially inhibited by a pre-treatment with haloperidol or ρCPA. Despite similar actions on locomotion, analgesia, and depression-like behavior, the acute administration of mephedrone and methedrone elicited divergent effects on anxiety-like behavior and stereotyped movements in mice, which might be related to the distinct modulation of brain tissue neurotransmitter levels.

Protective effects of resveratrol on hepatotoxicity induced by isoniazid and rifampicin via SIRT1 modulation.

Acute liver injury was induced in male BALB/c mice by coadministering isoniazid and rifampicin. In this work, the effects of resveratrol (1) were investigated in the hepatotoxicity caused by isoniazid-rifampicin in mice. Compound 1 was administered 30 min prior to isoniazid-rifampicin. Serum biochemical tests, liver histopathological examination, oxidative stress, myeloperoxidase activity, cytokine production (TNF-α, IL-12p70, and IL-10), and mRNA expression of SIRT1-7 and PPAR-γ/PGC1-α were evaluated. The administration of 1 significantly decreased aspartate transaminase and alanine aminotransferase levels, myeloperoxidase activity, and cytokine levels. Furthermore, 1 reverted the decrease of catalase and glutathione activities and ameliorated the histopathological alterations associated with antituberculosis drugs. Modulation of SIRT1 and PPAR-γ/PGC1-α expression is likely involved in the protective effects of 1. The results presented herein show that 1 was able to largely prevent the hepatotoxicity induced by isoniazid and rifampicin in mice, mainly by modulating SIRT1 mRNA expression.

Effects of D-series resolvins on behavioral and neurochemical changes in a fibromyalgia-like model in mice.

This study investigated whether the spinal or systemic treatment with the lipid resolution mediators resolvin D1 (RvD1), aspirin-triggered resolvin D1 (AT-RvD1) and resolvin D2 (RvD2) might interfere with behavioral and neurochemical changes in the mouse fibromyalgia-like model induced by reserpine. Acute administration of AT-RvD1 and RvD2 produced a significant inhibition of mechanical allodynia and thermal sensitization in reserpine-treated mice, whereas RvD1 was devoid of effects. A similar antinociceptive effect was obtained by acutely treating animals with the reference drug pregabalin. Noteworthy, the repeated administration of AT-RvD1 and RvD2 also prevented the depressive-like behavior in reserpine-treated animals, according to assessment of immobility time, although the chronic administration of pregabalin failed to affect this parameter. The induction of fibromyalgia by reserpine triggered a marked decrease of dopamine and serotonin (5-HT) levels, as examined in total brain, spinal cord, cortex and thalamus. Reserpine also elicited a reduction of glutamate levels in total brain, and a significant increase in the spinal cord and thalamus. Chronic treatment with RvD2 prevented 5-HT reduction in total brain, and reversed the glutamate increases in total brain and spinal cord. Otherwise, AT-RvD1 led to a recovery of dopamine levels in cortex, and 5-HT in thalamus, whilst it diminished brain glutamate contents. Concerning pregabalin, this drug prevented dopamine reduction in total brain, and inhibited glutamate increase in brain and spinal cord of reserpine-treated animals. Our data provide novel evidence, showing the ability of D-series resolvins AT-RvD1, and mainly RvD2, in reducing painful and depressive symptoms allied to fibromyalgia in mice.

Long-term exposure to paraquat alters behavioral parameters and dopamine levels in adult zebrafish (Danio rerio).

Chronic exposure to paraquat (Pq), a toxic herbicide, can result in Parkinsonian symptoms. This study evaluated the effect of the systemic administration of Pq on locomotion, learning and memory, social interaction, tyrosine hydroxylase (TH) expression, dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels, and dopamine transporter (DAT) gene expression in zebrafish. Adult zebrafish received an i.p. injection of either 10 mg/kg (Pq10) or 20 mg/kg (Pq20) of Pq every 3 days for a total of six injections. Locomotion and distance traveled decreased at 24 h after each injection in both treatment doses. In addition, both Pq10- and Pq20-treated animals exhibited differential effects on the absolute turn angle. Nonmotor behaviors were also evaluated, and no changes were observed in anxiety-related behaviors or social interactions in Pq-treated zebrafish. However, Pq-treated animals demonstrated impaired acquisition and consolidation of spatial memory in the Y-maze task. Interestingly, dopamine levels increased while DOPAC levels decreased in the zebrafish brain after both treatments. However, DAT expression decreased in the Pq10-treated group, and there was no change in the Pq20-treated group. The amount of TH protein showed no significant difference in the treated group. Our study establishes a new model to study Parkinson-associated symptoms in zebrafish that have been chronically treated with Pq.

Efficacy and gastrointestinal tolerability of ML3403, a selective inhibitor of p38 MAP kinase and CBS-3595, a dual inhibitor of p38 MAP kinase and phosphodiesterase 4 in CFA-induced arthritis in rats.

OBJECTIVE: Mitogen-activated protein kinase (MAPK) p38 inhibitors have entered the clinical phase, although many of them have failed due to high toxicity and lack of efficacy. In the present study we compared the effects of the selective p38 inhibitor ML3403 and the dual p38-PDE4 inhibitor CBS-3595, on inflammatory and nociceptive parameters in a model of polyarthritis in rats. METHODS: Male Wistar rats (180-200 g) were used for the complete Freund's adjuvant (CFA)-induced arthritis model and they were evaluated at 14-21 days. We also analysed the effects of these pharmacological tools on liver and gastrointestinal toxicity and on cytokine levels. RESULTS: Repeated CBS-3595 (3 mg/kg) or ML3403 (10 mg/kg) administration produced significant anti-inflammatory actions in the chronic arthritis model induced by CFA. CBS-3595 and ML3403 treatment also markedly reduced the production of the proinflammatory cytokine IL-6 in the paw tissue, whereas it widely increased the levels of the anti-inflammatory cytokine IL-10. Moreover, CBS-3595 produced partial anti-allodynic effects in the CFA model at 4 and 8 days after treatment. Notably, ML3403 and CBS-3595 did not show marked signs of hepatoxicity, as supported by unaltered histological observations in the liver sections. Finally, both compounds were safe in the gastrointestinal tract, according to evaluation of intestinal biopsies. CONCLUSION: CBS-3595 displayed a superior profile regarding its anti-inflammatory effects. Thus p38 MAPK/PDE4 blocking might well constitute a relevant strategy for the treatment of RA.

Outcome of periapical lesions in a rat model of type 2 diabetes: refractoriness to systemic antioxidant therapy.

INTRODUCTION: This study evaluated the development of periapical lesions in a rat model of type 2 diabetes and assessed the potential actions of the antioxidant agent tempol in this model. METHODS: Male Wistar rats were used; they received tap water (N = 5) or a 20% glucose solution (N = 15) during a period of 9 weeks. At the sixth week, periapical lesions were induced on the first mandibular molars, and the animals were subdivided into 4 groups. The subgroup 1 was composed of nondiabetic rats orally receiving saline solution (10 mL/kg). Chronically glucose-fed rats were divided into the following subgroups: (2) saline-treated animals (10 mL/kg by oral route), and animals treated with tempol by gavage at doses of (3) 50 mg/kg or (4) 100 mg/kg. The body weight was monitored thoroughly. After 21 days of apical periodontitis induction, the animals were killed, and the mandibles were collected and submitted to radiographic and histologic analysis. The livers were collected to determine free radicals, and the blood plasma was used to measure insulin levels. RESULTS: Type 2 diabetic rats displayed a significant decrease of body weight gain and a slight increase of insulin levels, which were allied to reduced levels of the antioxidant components catalase and reduced glutathione; these alterations were reversed by tempol. Concerning the periapical lesions, neither radiographic nor histologic analysis revealed any significant difference between control and type 2 diabetic rats. In diabetic rats, the apical periodontitis was refractory to tempol treatment. CONCLUSIONS: The extent and cellularity of periapical lesions in glucose-fed type 2 diabetic rats were similar to those seen in control rats. Despite affecting other parameters related to diabetes, tempol failed to improve the outcome of endodontic lesions in type 2 diabetic animals.

Seizures induced by pentylenetetrazole in the adult zebrafish: a detailed behavioral characterization.

Pentylenetetrazole (PTZ) is a common convulsant agent used in animal models to investigate the mechanisms of seizures. Although adult zebrafish have been recently used to study epileptic seizures, a thorough characterization of the PTZ-induced seizures in this animal model is missing. The goal of this study was to perform a detailed temporal behavior profile characterization of PTZ-induced seizure in adult zebrafish. The behavioral profile during 20 min of PTZ immersion (5, 7.5, 10, and 15 mM) was characterized by stages defined as scores: (0) short swim, (1) increased swimming activity and high frequency of opercular movement, (2) erratic movements, (3) circular movements, (4) clonic seizure-like behavior, (5) fall to the bottom of the tank and tonic seizure-like behavior, (6) death. Animals exposed to distinct PTZ concentrations presented different seizure profiles, intensities and latencies to reach all scores. Only animals immersed into 15 mM PTZ showed an increased time to return to the normal behavior (score 0), after exposure. Total mortality rate at 10 and 15 mM were 33% and 50%, respectively. Considering all behavioral parameters, 5, 7.5, 10, and 15 mM PTZ, induced seizures with low, intermediate, and high severity, respectively. Pretreatment with diazepam (DZP) significantly attenuated seizure severity. Finally, the brain PTZ levels in adult zebrafish immersed into the chemoconvulsant solution at 5 and 10 mM were comparable to those described for the rodent model, with a peak after a 20-min of exposure. The PTZ brain levels observed after 2.5-min PTZ exposure and after 60-min removal from exposure were similar. Altogether, our results showed a detailed temporal behavioral characterization of a PTZ epileptic seizure model in adult zebrafish. These behavioral analyses and the simple method for PTZ quantification could be considered as important tools for future investigations and translational research.

Effects of treatment with enalapril on hepatotoxicity induced by acetaminophen in mice.

There is a current need for new therapeutic options for acetaminophen (APAP)-induced hepatotoxicity. Herein, we assessed the effects of prophylactic and therapeutic treatment with the angiotensin-converting enzyme (ACE) inhibitor, enalapril, on APAP-caused hepatotoxicity. Male and female C57BL/6 J mice were used, and hepatotoxicity was induced by a single application of APAP (400 mg/kg, i.p.). Macroscopic and histological liver alterations, serum alanine transaminase (ALT) and aspartate transaminase (AST) activity, liver catalase activity (CAT), reduced glutathione concentrations (GSH), hepatic measurement of neutrophil migration (myeloperoxidase, MPO activity), and caspase-3 liver expression were evaluated. The prophylactic and the therapeutic treatments with enalapril were able to markedly reduce the macroscopic and histological liver alterations as well as the caspase-3 immunopositivity. Both schedules of treatment were also effective in reducing GSH concentrations as well as neutrophil migration. Conversely, only the pre-treatment (but not the post-administration) with enalapril significantly reversed APAP-induced CAT decrease. Furthermore, the pre- or the post-treatment with enalapril largely reduced ALT and AST serum activity in APAP-intoxicated mice. The hepatoprotective effects of enalapril were comparable to those obtained with the clinically used compound N-acetylcysteine (NAC) when given in a therapeutic regimen. Data obtained with the prophylactic protocol of treatment might indicate that individuals under treatment with ACE inhibitors are less susceptible to the toxic effects of APAP. Additionally, the therapeutic approach allows us to suggest that enalapril might represent an innovative tool for treating APAP intoxication.

Behavioral effects of taurine pretreatment in zebrafish acutely exposed to ethanol.

Taurine (TAU) is an amino sulfonic acid that plays protective roles against neurochemical impairments induced by ethanol (EtOH). Mounting evidence shows the applicability of zebrafish for evaluating locomotor parameters and anxiety-like behavioral phenotypes after EtOH exposure in a large scale manner. In this study, we assess the effects of TAU pretreatment on the behavior of zebrafish in the open tank after acute 1% EtOH (v/v) exposure (20 and 60 min of duration) and on brain alcohol contents. The exposure for 20 min exerted significant anxiolytic effects, which were prevented by 42, 150, and 400 mg/L TAU. Conversely, the 60-min condition induced depressant/sedative effects, in which the changes on vertical activity were associated to modifications on the exploratory profile. Although all TAU concentrations kept locomotor parameters at basal levels, 150 mg/L TAU, did not prevent the impairment on vertical activity of EtOH[60]. Despite the higher brain EtOH content detected in the 60-min exposure, 42, 150, and 400 mg/L TAU attenuated the increase of alcohol content in EtOH[60] group. In conclusion, our data suggest that both protocols of acute EtOH exposure induce significant changes in the spatio-temporal behavior of zebrafish and that TAU may exert a preventive role by antagonizing the effects induced by EtOH possibly due to its neuromodulatory role and also by decreasing brain EtOH levels. The hormetic dose-response of TAU on vertical exploration suggests a complex interaction between TAU and EtOH in the central nervous system.

Effects of the hydroalcoholic extract of Phyllanthus niruri and its isolated compounds on cyclophosphamide-induced hemorrhagic cystitis in mouse.

The effects of Phyllanthus niruri hydroalcoholic extract and the isolated compounds quercetin, rutin, and gallic acid were examined in the mouse model of cyclophosphamide (CYP)-induced hemorrhagic cystitis (HC). HC was induced by a single CYP injection (300 mg/kg, IP), and the animals were evaluated 4 and 6 h after. Some animals were orally treated with the reference compound 2-mercaptoethane sodium sulfonate (Mesna) 80 mg/kg (30 min before CYP) and 160 mg/kg (2 h after CYP). Other groups were treated with P. niruri extract (30 and 50 mg/kg), or quercetin, rutin, and gallic acid (10 and 20 mg/kg), given orally, at the same intervals described for Mesna. P. niruri extract and its active components produced a significant attenuation of the nociception, edema, and hemorrhage evoked by CYP, which was similar to that seen for Mesna. Gallic acid and rutin displayed greater anti-inflammatory effects, whereas quercetin presented superior antinociceptive activities. Noteworthy is that P. niruri extract and compounds significantly reduced CYP-induced liver lipid peroxidation. Our results shed new light on the beneficial effects of P. niruri extract and its active compounds in attenuating the collateral effects elicited by the chemotherapeutic agent CYP.

Rimonabant: an antagonist drug of the endocannabinoid system for the treatment of obesity.

Obesity, an ever-increasing problem in the industrialized world, has long been a target of research for a cure or, at least, control of its expansion. In the search for treatment, the recently discovered endocannabinoid system has emerged as a new target for controlling obesity and its associated conditions. The endocannabinoid system plays an important role in controlling weight and energy balance in humans. This system is activated to a greater extent in obese patients, and the specific blockage of its receptors is the aim of rimonabant, one of the most recent drugs created for the treatment of obesity. This drug acts as a blockade for endocannabinoid receptors found in the brain and peripheral organs that play an important role on carbohydrate and fat metabolism. Clinical studies have confirmed that, when used in combination with a low calorie diet, rimonabant promotes loss in body weight, loss in abdominal circumference, and improvements in dyslipidemia. Rimonabant is also being tested as a potential anti-smoking treatment since endocannabinoids are related to the pleasurable effect of nicotine. Thus, rimonabant constitutes a new therapeutic approach to obesity and cardiovascular risk factors. Studies show effectiveness in weight loss; however, side effects such as psychiatric alterations have been reported, including depression and anxiety. These side effects have led the FDA (Food and Drug Administration) to not approve this drug in the United States. For a more complete evaluation on the safety of this drug, additional studies are in progress.

Anti-Inflammatory effects of low-level laser therapy (660 nm) in the early phase in carrageenan-induced pleurisy in rat.

BACKGROUND AND OBJECTIVE: In the classic model of pleurisy there is little evidence about the anti-inflammatory effects of low-level laser therapy (LLLT) as well the dosage characteristics, such as wavelength, total energy, number and pattern of treatment. In this study we investigated the potential effects of LLLT on modulating the pro-inflammatory and anti-inflammatory mediators of acute inflammation in a rat pleurisy model. STUDY DESIGN/MATERIALS AND METHODS: A sample of 48 female Wistar rats were divided into control and experiential groups. An inflammation was induced by carrageenan (0.2 ml) injected into the pleural cavity. At 1, 2, and 3 hours after induction a continuous wave (20 mW) diode laser of the InGaAlP (660 nm) type was used in the four laser groups with different doses and treatment patterns. One group received a single dose of 2.1 J and the other three groups received a total energy of 0.9, 2.1, and 4.2 J. Four hours later the exudate volume, total and differential leukocytes, protein concentration, NO, IL-6, IL-10, TNF-alpha, and MCP-1 were measured from the aspirated liquid. RESULTS: All the treatment patterns and quantity of energy studied show significant reduction of the exudate volume (P<0.05). Using energy of 0.9 J only NO, IL-6, MCP-1 and IL-10 are significantly reduced (P<0.05). On the other hand, higher energies (2.1 and 4.2 J) significantly reduce all variables independently of the treatment pattern. The neutrophil migration has a straight correlation with the TNF-alpha (r = 0.551) and NO (r = 0.549) concentration. CONCLUSIONS: LLLT-660 nm induced an anti-inflammatory effect characterized by inhibition of either total or differential leukocyte influx, exudation, total protein, NO, IL-6, MCP-1, IL-10, and TNF-alpha, in a dose-dependent manner. Under these conditions, laser treatment with 2.1 J was more effective than 0.9 and 4.2 J.

Anti-inflammatory effects of red pepper (Capsicum baccatum) on carrageenan- and antigen-induced inflammation.

Inflammation is a pivotal component of a variety of diseases, such as atherosclerosis and tumour progression. Various naturally occurring phytochemicals exhibit anti-inflammatory activity and are considered to be potential drug candidates against inflammation-related pathological processes. Capsicum baccatum L. var. pendulum (Willd.) Eshbaugh (Solanaceae) is the most consumed species in Brazil, and its compounds, such as capsaicinoids, have been found to inhibit the inflammatory process. However, the anti-inflammatory effects of C. baccatum have not been characterized. Thus, this study was designed to evaluate the effects of C. baccatum juice in animal models of acute inflammation induced by carrageenan and immune inflammation induced by methylated bovine serum albumin. Pretreatment (30 min) of rats with pepper juice (0.25-2.0 g kg(-1)) significantly decreased leucocyte and neutrophil migration, exudate volume and protein and LDH concentration in pleural exudates of a pleurisy model. This juice also inhibited neutrophil migration and reduced the vascular permeability on carrageenan-induced peritonitis in mice. C. baccatum juice also reduced neutrophil recruitment and exudate levels of pro-inflammatory cytokines TNF-alpha and IL-1beta in mouse inflammatory immune peritonitis. Furthermore, we demonstrated that the main constituent of C. baccatum juice, as extracted with chloroform, is capsaicin. In agreement with this, capsaicin was able to inhibit the neutrophil migration towards the inflammatory focus. To our knowledge, this is the first demonstration of the anti-inflammatory effect of C. baccatum juice and our data suggest that this effect may be induced by capsaicin. Moreover, the anti-inflammatory effect induced by red pepper may be by inhibition of pro-inflammatory cytokine production at the inflammatory site.

Marcadores laboratoriais do choque séptico / Laboratory markers of the septic shock

O deste trabalho foi fazer uma revisão sobre os principais marcadores laboratoriais de suporte para o diagnóstico do choque séptico. Foram pesquisados livros e artigos científicos, com enfoque nos assuntos abordados, publicados no período de 1989-2005. Os marcadores laboratoriais são úteis na avaliação do choque séptico, auxiliando no diagnóstico e na detecção precoce de disfunções orgânicas. No sangue e na urina destes pacientes se refletem as alterações biofísico-químicas que se operam nos tecidos, na vigência da deficiência circulatória dos chocados. A análise laboratorial pode revelar a maioria das alterações fisiopatológicas.