The role of Calmodulin inhibition in intrathecal Trifluoperazine-induced analgesia

گزارشاتی مبنی بر اثر ضد درد داروهای ضد جنون وجود دارد ولی مکانیسم آن کاملا شناخته شده نیست. از سوی دیگر مقالاتی نیز در مورد اثر ضد درد مهار کننده های کالمودولین در سال های اخیر انتشار یافته است. در بین داروهای ضد جنون تری فلوپرازین یکی از قویترین مهار کننده های کالمودولین می باشد. در این تحقیق بررسی اثر ضد درد تری فلوپرازین مدنظر قرار گرفته و از آنجایی که این دارو اثرات آنتی دوپامینرژیک، آنتی کلینرژیک، آنتی ادرنرژیک و آنتی هیستامینیک نیز دارد سعی شده رابطه اثر ضد درد با تاثیر این دارو بر گیرنده های فوق نیز مورد مطالعه قرار گیرد. بدین منظور بعد از کاتتریزاسیون فضای ساب آراکنوئید موش صحرایی داروهای مختلف بصورت داخل نخاعی تزریق و بعد از 15 دقیقه، حیوانات با تست فرمالین مورد ارزیابی قرار گرفتند. ضمنا باتوجه به اینکه اندازه گیری شدت درد در تست فرمالین وابسته به فعالیتهای حرکتی است، جهت تشخیص عوارض حرکتی داروهای مورد استفاده از تست روتارود استفاده گردید. نتایج حاصل را می توان به شرح زیر خلاصه نمود: دزهای پایین تری فلوپرازین (10µg/rat و 1) اثر ضد درد نشان داد و دز (100µg/rat) بالا منجر به هیپرالژزی (Hyperalgesia) شد. هیچگونه اثر ضد دردی بعد از تزریق داخل نخاعی سولپیراید، آتروپین، فنتول آمین و برموفنیرامین مشاهده نشد. کالمیدازولیوم به عنوان آنتاگونیست کالمودولین به صورت وابسته به دز (250µg/rat و 50 و 10) دارای آثار ضد درد بود. در تزریق همزمان تری فلوپرازین با فیزوستیگمین، هیستامین، بروموکریپتین و نوراپی نفرین تغییری در اثر ضد درد مشاهده نگردید. کلسیم اثر ضد درد کالمیدازولیوم را مهار و اثر ضد درد تری فلوپرازین را کاهش داد. نالوکسان بصورت نسبی باعث کاهش اثر ضد درد تری فلوپرازین گردید درصورتی که بر اثر ضد درد کالمیدازولیوم تاثیر قابل توجه نداشت. باتوجه به آزمایشات فوق می توان نتیجه گرفت که احتمالا اثر ضد درد دزهای پایین تری فلوپرازین نخاعی ناشی از مهار کالمودولین بوده است. با افزایش دوز، آثار دیگر تری فلوپرازین تفوق یافته که منجر به هیپرالژزی شده است. همچنین می توان نتیجه گرفت سیستم اپیوئیدی اگرچه در اثر ضد درد تری فلوپرازین نقش دارد ولی اثر ضد درد مهار کالمودولین جدای از این سیستم می باش

Protective role of vitamin B6 (PLP) against DNA damage in Drosophila models of type 2 diabetes

Growing evidence shows that improper intake of vitamin B6 increases cancer risk and several studies indicate that diabetic patients have a higher risk of developing tumors. We previously demonstrated that in Drosophila the deficiency of Pyridoxal 5' phosphate (PLP), the active form of vitamin B6, causes chromosome aberrations (CABs), one of cancer prerequisites, and increases hemolymph glucose content. Starting from these data we asked if it was possible to provide a link between the aforementioned studies. Thus, we tested the effect of low PLP levels on DNA integrity in diabetic cells. To this aim we generated two Drosophila models of type 2 diabetes, the first by impairing insulin signaling and the second by rearing flies in high sugar diet. We showed that glucose treatment induced CABs in diabetic individuals but not in controls. More interestingly, PLP deficiency caused high frequencies of CABs in both diabetic models demonstrating that hyperglycemia, combined to reduced PLP level, impairs DNA integrity. PLP-depleted diabetic cells accumulated Advanced Glycation End products (AGEs) that largely contribute to CABs as α-lipoic acid, an AGE inhibitor, rescued not only AGEs but also CABs. These data, extrapolated to humans, indicate that low PLP levels, impacting on DNA integrity, may be considered one of the possible links between diabetes and cancer

Crosstalk between JNK and SUMO Signaling Pathways: deSUMOylation Is Protective against H2O2-Induced Cell Injury

Background: Oxidative stress is a key feature in the pathogenesis of several neurological disorders. Following oxidative stress stimuli a wide range of pathways are activated and contribute to cellular death. The mechanism that couples c-Jun N-terminal kinase (JNK) signaling, a key pathway in stress conditions, to the small ubiquitin-related modifier (SUMO), an emerging protein in the field, is largely unknown. Methodology/Principal Findings: With this study we investigated if SUMOylation participates in the regulation of JNK activation as well as cellular death in a model of H 2O 2 induced-oxidative stress. Our data show that H 2O 2 modulates JNK activation and induces cellular death in neuroblastoma SH-SY5Y cells. Inhibition of JNK’s action with the D-JNKI1 peptide rescued cells from death. Following H2O2, SUMO-1 over-expression increased phosphorylation of JNK and exacerbated cell death, although only in conditions of mild oxidative stress. Furthermore inhibition of SUMOylation, following transfection with SENP1, interfered with JNK activation and rescued cells from H 2O 2 induced death. Importantly, in our model, direct interaction between these proteins can occur. Conclusions/Significance: Taken together our results show that SUMOylation may significantly contribute to modulation o

Abdominal obesity and metabolic syndrome: exercise as medicine?

Background: Metabolic syndrome is defined as a cluster of at least three out of five clinical risk factors: abdominal (visceral) obesity, hypertension, elevated serum triglycerides, low serum high-density lipoprotein (HDL) and insulin resistance. It is estimated to affect over 20% of the global adult population. Abdominal (visceral) obesity is thought to be the predominant risk factor for metabolic syndrome and as predictions estimate that 50% of adults will be classified as obese by 2030 it is likely that metabolic syndrome will be a significant problem for health services and a drain on health economies.Evidence shows that regular and consistent exercise reduces abdominal obesity and results in favourable changes in body composition. It has therefore been suggested that exercise is a medicine in its own right and should be prescribed as such. Purpose of this review: This review provides a summary of the current evidence on the pathophysiology of dysfunctional adipose tissue (adiposopathy). It describes the relationship of adiposopathy to metabolic syndrome and how exercise may mediate these processes, and evaluates current evidence on the clinical efficacy of exercise in the management of abdominal obesity. The review also discusses the type and dose of exercise needed for optimal improvements in health status in relation to the available evidence and considers the difficulty in achieving adherence to exercise programmes. Conclusion: There is moderate evidence supporting the use of programmes of exercise to reverse metabolic syndrome although at present the optimal dose and type of exercise is unknown. The main challenge for health care professionals is how to motivate individuals to participate and adherence to programmes of exercise used prophylactically and as a treatment for metabolic syndrome

MsrA Overexpression Targeted to the Mitochondria, but Not Cytosol, Preserves Insulin Sensitivity in Diet-Induced Obese Mice

The authors thank Dr. Rod Levine and his laboratory at NIH/NHLBI for sharing MsrA transgenic and knockout mice.There is growing evidence that oxidative stress plays an integral role in the processes by which obesity causes type 2 diabetes. We previously identified that mice lacking the protein oxidation repair enzyme methionine sulfoxide reductase A (MsrA) are particularly prone to obesity-induced insulin resistance suggesting an unrecognized role for this protein in metabolic regulation. The goals of this study were to test whether increasing the expression of MsrA in mice can protect against obesity-induced metabolic dysfunction and to elucidate the potential underlying mechanisms. Mice with increased levels of MsrA in the mitochondria (TgMito MsrA) or in the cytosol (TgCyto MsrA) were fed a high fat/high sugar diet and parameters of glucose homeostasis were monitored. Mitochondrial content, markers of mitochondrial proteostasis and mitochondrial energy utilization were assessed. TgMito MsrA, but not TgCyto MsrA, mice remain insulin sensitive after high fat feeding, though these mice are not protected from obesity. This metabolically healthy obese phenotype of TgMito MsrA mice is not associated with changes in mitochondrial number or biogenesis or with a reduction of proteostatic stress in the mitochondria. However, our data suggest that increased mitochondrial MsrA can alter metabolic homeostasis under diet-induced obesity by activating AMPK signaling, thereby defining a potential mechanism by which this genetic alteration can prevent insulin resistance without affecting obesity. Our data suggest that identification of targets that maintain and regulate the integrity of the mitochondrial proteome, particular against oxidative damage, may play essential roles in the protection against metabolic disease.Yeshttp://www.plosone.org/static/editorial#pee