Attenuation of withdrawal signs, blood cortisol, and glucose level with various dosage regimens of morphine after precipitated withdrawal syndrome in mice

Morphine withdrawal usually results in unsuccessful outcomes. Despite partial benefits from alternative substances such as methadone, its use may not lead to the desired result due to the lack of mental tranquility during the withdrawal period. In this study, by means of an animal model, morphine itself was used to manage morphine dependence. Forty mice were divided into 5 groups, in which 4 groups became dependent by increasing daily doses of morphine for 7 days (15-45 mg/kg). Afterwards, the animals received morphine for 14 days by either of the following regimens: � Once daily 45 mg/kg (positive controls) � Increasing the interval (each time 6 hours longer than the previous interval) � Irregular interval in every 36, 12 and 24 hours until the 21th day � 12, 24, 36 hours decreasing doses (each time 2.5 mg/kg less than the former dosage). Negative controls received saline solution only. On day 22, total withdrawal index (TWI) was determined by injecting 3 mg/kg of naloxone. Thereafter, blood samples were taken for the measurement of cortisol and glucose levels. TWI significantly decreased in all test groups in comparison with the positive control animals (P<0.001). Cortisol levels significantly decreased when either the dosage or the administration frequencies were decreased on a regular and gradual basis (P<0.005). Blood glucose levels significantly decreased in animals that received decreasing doses of morphine (P<0.005). This study suggests that no other measures may be required in clinical practice except for changing the dosage regimen of morphine for the cessation of self-administration. © 2016, Shiraz University of Medical Sciences. All rights reserved

Immune sensitization of equine bronchus: glutathione, IL-1β expression and tissue responsiveness

BACKGROUND: Increasing clinical epidemiological and experimental evidence indicates that excess of production of reactive oxygen free radicals (ROS) induced by an oxidative stress is involved in the pathogenesis of a number of human airway disorders, as well as equine recurrent airway obstruction. Free-radicals modulate the activation of transcription factors, such as nuclear factor-(NF)-κB and activator protein (AP)-1, in several different cells. This activation leads to expression of many pro-inflammatory cytokines, including interleukin (IL)-1β. We have hypothesized that equine airway sensitization might induce an oxidative stress and increase the ROS production, which in turn might enhance a production of IL-1β and airway hyperresponsiveness. METHODS: We have examined the effect of passive sensitization on IL-1β mRNA expression and electrical field stimulation (EFS)-induced contraction in equine isolated bronchi, and the potential interference of reduced-glutathione (GSH), an antioxidant, with these responses. Bronchi passively sensitized with serum from animals suffering from heaves and having high total level of IgE, and control tissues, either pretreated or not with GSH (100 μM), were used to quantify IL-1β mRNA. Other tissues were used to study the effect of EFS (3–10–25 Hz). RESULTS: Mean IL-1β mRNA expression was higher in passively sensitized than in control rings. GSH significantly (p < 0.05) reduced the IL-1β mRNA expression only in passively sensitized bronchi. ELF induced a frequency-dependent contraction in both non-sensitized and passively sensitized tissues, with a significantly greater response always observed in sensitized tissues. GSH did not modify the EFS-induced contraction in non-sensitized bronchi, but significantly (p < 0.05) decreased it in passively sensitized tissues. CONCLUSION: Our data indicate that the passive sensitization of equine bronchi induces inflammation and hyperresponsiveness. These effects might be due to an oxidative stress because a pretreatment with GSH decreased the increased IL-1β mRNA expression and responsiveness to EFS of passively sensitized bronchi

Nitric oxide: a pro-inflammatory mediator in lung disease?

Inflammatory diseases of the respiratory tract are commonly associated with elevated production of nitric oxide (NO•) and increased indices of NO• -dependent oxidative stress. Although NO• is known to have anti-microbial, anti-inflammatory and anti-oxidant properties, various lines of evidence support the contribution of NO• to lung injury in several disease models. On the basis of biochemical evidence, it is often presumed that such NO• -dependent oxidations are due to the formation of the oxidant peroxynitrite, although alternative mechanisms involving the phagocyte-derived heme proteins myeloperoxidase and eosinophil peroxidase might be operative during conditions of inflammation. Because of the overwhelming literature on NO• generation and activities in the respiratory tract, it would be beyond the scope of this commentary to review this area comprehensively. Instead, it focuses on recent evidence and concepts of the presumed contribution of NO• to inflammatory diseases of the lung

Effects of Chronic Exposure to Lead Acetate on the Reactions to Painful Stimuli in Mice

Introduction: Influences of lead on functions of many organ systems are known, but less experimental studies has been done on influences over the behavior, including pain sensation. This study was carried out to reveal possible changes in the onset and intensity of reactions to painful stimuli in mice, after long-term exposure to lead acetate. Methods: In this experimental study, 24 adult male albino mice were divided randomly into 3 groups of 8 each. Control group received fresh water ad lib and 2 treated groups received drinking water contaminated by either 5 ppm or 500 ppm of LA for 90 consecutive days. On the day of 91, nociceptive were performed using a hot plate and formalin, to evaluate onset and intensity of&nbsp; reaction in response to the thermal and chemical pain, respectively. At the end, the animals were euthanized and blood samples were collected for determination of cortisol levels using an ELISA assay. Results: The animals exposed to LA showed a delay in reaction to painful stimuli induced by thermal stimulus by 52% and 59% with low and high doses, respectively. Thermal pain intensity of reactions to was declined by 63% with LA 5 ppm and by 82% with LA 500 ppm (P<0.05). Delayed reaction to chemical stimulus was also prominent in treated groups up to 68% and the pain intensity was declined by 80%, but they were not statistically significant. Blood cortisol levels remained almost unchanged. Conclusion: Delayed reaction to painful stimuli after chronic LA exposure may be considered as a complication which weaken the alarming role of the pain. Further studies regarding the mechanism of action and the extent of the importance of these effects are warranted

Role of the epithelial layer in the generation of superoxide anion by the guinea-pig isolated trachea

The lucigenin-dependent chemiluminescence generation by guinea-pig isolated tracheal two rings preparations was studied. Tracheal preparations stimulated with phorbol myristate acetate (PMA) or opsonized zymosan generated chemiluminescence. The total amount of chemiluminescence generated in 120 min was 754 ± 63 mV × min for PMA and 4832 ±396 mV × min for zymosan. Generation of chemiluminescence was decreased by more than 50% when the tissues were co-incubated with superoxide dismutase (100 U/ml). Also, addition of direct donors of nitric oxide diminished chemiluminescence generation by zymosan-activated tracheal rings significantly by about 50%. However, the presence of the precursor or of inhibitors of nitric oxide synthase did not influence zymosan-induced chemiluminescence. Removal of the epithelial layer from tracheal rings caused an approximately 90% decrease in chemiluminescence response. However, isolated epithelial cell suspensions did not generate chemiluminescence. Histologic examination showed that the number of eosinophils in the tracheal tissue was reduced from 56 ± 7 to 18 ± 8 per mm basal membrane when the epithelial layer was removed. These results indicated that (1) superoxide anion formation can take place in the guinea-pig trachea, (2) eosinophils in the epithelial and submucosal layers of guinea-pig trachea are likely candidates for superoxide generation although other cell types can also be involved, and (3) besides relaxing airway smooth muscle, nitric oxide donors may also affect superoxide in the airways

L-Thyroxine promotes a proliferative airway smooth muscle phenotype in the presence of TGF-β1

Hypothyroidism may reduce, whereas hyperthyroidism may aggravate asthma symptoms. The mechanisms underlying this relationship are largely unknown. Since thyroid hormones have central roles in cell growth and differentiation, we hypothesized that airway remodeling, in particular increased airway smooth muscle (ASM) mass, may be involved. To address this hypothesis, we investigated the effects of triiodothyronine (T3) and L-thyroxine (T4) in the absence and presence of the profibrotic transforming growth factor (TGF)-β1 on human ASM cell phenotype switching. T3 (1-100 nM) and T4 (1-100 nM) did not affect basal ASM proliferation. However, when combined with TGF-β1 (2 ng/ml) T4 synergistically increased the proliferative response, whereas only a minor effect was observed for T3. In line with a switch from a contractile to a proliferative ASM phenotype, T4 reduced the TGF-β1-induced contractile protein expression by approximately 50%. Co-treatment with T3 reduced TGF-β1-induced contractile protein expression by approximately 25%. The synergistic increase in proliferation was almost fully inhibited by the integrin αvβ3 antagonist tetrac (100 nM), whereas no significant effects of the thyroid receptor antagonist 1-850 (3 µM) were observed. Inhibition of MEK1/2, downstream of the αvβ3 integrin, also inhibited the T4- and TGF-β1-induced proliferative responses. Collectively, the results indicate that T4 and to a lesser extent T3 promotes a proliferative ASM phenotype in the presence of TGF-β1, which is predominantly mediated by the membrane bound T4 receptor αvβ3. These results indicate that thyroid hormones may enhance ASM remodeling in asthma, which could be of relevance for hyperthyroid patients with this disease