After a Turkish scientist took Nobel Prize due to his contributions to understand clock genes, melatonin, closely related to these genes, may begin to shine. Melatonin, a hormone secreted from the pineal gland at night, plays roles in regulating sleep-wake cycle, pubertal development and seasonal adaptation. Melatonin has antinociceptive, antidepressant, anxiolytic, antineophobic, locomotor activityregulating, neuroprotective, anti-inflammatory, pain-modulating, blood pressure-reducing, retinal, vascular, anti-tumor and antioxidant effects. It is related with memory, ovarian physiology, and osteoblast differentiation. Pathologies associated with an increase or decrease in melatonin levels are summarized in the review. Melatonin affects by four mechanisms: 1) Binding to melatonin receptors in plasma membrane, 2) Binding to intracellular proteins such as calmoduline, 3) Binding to Orphan nuclear receptors, and 4) Antioxidant effect. Receptors associated with melatonin are as follows: 1) Melatonin receptor type 1a: MT1 (on cell membrane), 2) Melatonin receptor type 1b: MT2 (on cell membrane), 3) Melatonin receptor type 1c (found in fish, amphibians and birds), 4) Quinone reductase 2 enzyme (MT3 receptor, a detoxification enzyme), 5) RZR/RORα: Retinoid-related Orphan nuclear hormone receptor (with this receptor, melatonin binds to the transcription factors in nucleus), and 6) GPR50: X-linked Melatonin-related Orphan receptor (it is effective in binding of melatonin to MT1). Melatonin agonists such as ramelteon, agomelatine, circadin, TIK-301 and tasimelteon are introduced and side effects will be discussed. In conclusion, melatonin and related drugs is a new and promising era for medicine. Melatonin receptors and melatonin drugs will take attention with greater interest day by day in the future. Keywords: Melatonin, receptors, agonists, pineal gland ÖzSaat genlerini anlamamıza olan katkısından dolayı bir Türk bilim adamı Nobel ödülünü aldıktan sonra, bu genlerle yakın ilişkili olan melatoninin önemi arttı. Melatonin, pineal bezden gece salınan bir hormondur, uyku/uyanıklık döngüsünde, pubertal gelişimde ve mevsimsel adaptasyonda rol alır. Melatoninin antinosiseptif, antidepresan, anksiyolitik, antineofobik, locomotor aktiviteyi düzenleyici, nöroprotektif, antiinflamatuvar, ağrı dü-zenleyici, kan basıncını düşürücü, retinal, vasküler, tümör baskılayıcı ve antioksidan etkileri vardır. Hafıza, over fizyolojisi ve osteoblast diferansiasyonuyla ilişkilidir. Melatonin seviyelerinde artış veya azalışla seyreden patolojiler derlemede özetlenmiştir. Melatonin 4 mekanizmayla etkir: 1) Plazma membranında melatonin reseptörlerine bağlanma, 2) Kalmodulin gibi hücre içi reseptörlere bağlanma, 3) Yetim nükleer reseptörlere bağlanma, 4) Antioksidan etkiler. Melatoninle ilişkili reseptörler şunlardır: 1) Melatonin reseptör tip1a: MT1 (hücre zarında), 2) Melatonin reseptör tip1b: MT2 (hücre zarında), 3) Melatonin reseptör tip1c (balık, amfibiler ve kuşlarda bulunur), 4) Kuinon redüktaz-2 enzimi (MT3 reseptörü, bir detoksifika...

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Bosentan reduces intraocular inflammation and has similar effects as dexamethasone in a rat model of EIU.

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BackgroundDifferent medical therapies are employed in acute lung injury (ALI) but there is still a debate about the efficacy of these drugs. Among these therapies steroids are clinically applied and bosentan is experimentally studied. The aim of this study was to evaluate the efficacy of these two drugs to treat inflammation in ALI by histopathological comparison.MethodsThe five experimental groups (n = 5 per group) were: saline control (Group I); lipopolysaccharide (LPS) + saline (Group II); LPS + dexamethasone (Group III); LPS + 50 mg/kg bosentan (Group IV); and LPS + 100 mg/kg bosentan (Group V). Bosentan was administered orally one hour before and 12 hours after LPS treatment. Dexamethasone was administered intraperitoneally in three doses of 1 mg/kg; one dose was co-administered with LPS and the other two doses were given respectively 30 minutes before and after LPS treatment. Vasodilation-congestion, hemorrhage, polymorphonuclear leukocyte (PMN) infiltration, mononuclear leukocyte (MNL) infiltration, alveolar wall thickening, alveolar destruction/emphysematous appearance, and focal organization were the parameters used as criteria for evaluating inflammation and efficacy of treatment.ResultsCompared to the LPS-only group (Group II), dexamethasone treatment (Group III) resulted in significant improvements in vasodilation-congestion, hemorrhage, PMN and MNL infiltration, alveolar wall thickening and emphysematous areas. Treatment with 50 mg/kg dose of bosentan (Group IV) also resulted in significant improvements in hemorrhage, PMN and MNL infiltration, alveolar wall thickening and alveolar destruction. Reducing lung injury and reparative effects of 100 mg/kg bosentan were significant in all parameters.ConclusionsBosentan is as effective as dexamethasone for treating lung injury in ALI. Bosentan at 100 mg/kg can be recommended as a first treatment choice based on its significant reducing lung injury and reparative effects.