objective: critical macromolecules such as dna maybe damaged by free radicals that are generated from the interaction of ionizing radiation with biological systems. melatonin and vitamin c have been shown to be direct free radical scavengers. the aim of this study was to investigate the in vivo/in vitro radioprotective effects of melatonin and vitamin c separately and combined against genotoxic...

background: during the detorsion of a torsioned ovary, oxidant agents are released and melatonin as an antioxidant can reduce ischemia. we studied the histopathological changes after using melatonin on experimental torsioned ovary in cat. objective: the aim of this experimental study was to investigate the effects of melatonin on histopathological changes in torsion – detorsion injury in cat ov...

The pineal hormone melatonin elicits two effects on the suprachiasmatic nuclei (SCN): acute neuronal inhibition and phase-shifting. Melatonin evokes its biological effects through G protein-coupled receptors. Since the Mel1a melatonin receptor may transduce the major neurobiological actions of melatonin in mammals, we examined whether it mediates both melatonin effects on SCN function by using ...

statement of the problem melatonin has powerful antioxidant effects, has an immunomodulatory role, stimulates the synthesis of type i collagen fibers, and promotes bone formation. melatonin is also secreted in the saliva, although its role in the mouth is not known well purpose the aim of this study was to examine the correlation between salivary melatonin level and periodontal diseases materia...

objective(s): there are few reports have demonstrated the effect of a change-in-light experience on the structure and function of hippocampus. a change-in-light experience also affects the circadian pattern of melatonin secretion. this study aimed to investigate developmental effect of exogenous melatonin on synaptic plasticity of hippocampus of light deprived rats. materials and methods: the e...

this study investigates the effects of melatonin on the sperm quality and testis weight after the combination of swimming exercise and nandrolone decanoate (deca). two groups of male wistar rats were treated for eight weeks as follows; group a consist of co (control), sham, n (deca), s (swimming) and ns (deca plus swimming); and group b: sham m (sham melatonin), m (melatonin), mn (melatonin plu...

The hormone melatonin phase shifts circadian rhythms generated by the mammalian biological clock, the suprachiasmatic nucleus (SCN) of the hypothalamus, through activation of G protein-coupled MT2 melatonin receptors. This study demonstrated that pretreatment with physiological concentrations of melatonin (30-300 pM or 7-70 pg/mL) decreased the number of hMT2 melatonin receptors heterologously ...

We studied the subcellular levels of melatonin in cerebral cortex and liver of rats under several conditions. The results show that melatonin levels in the cell membrane, cytosol, nucleus, and mitochondrion vary over a 24-hr cycle, although these variations do not exhibit circadian rhythms. The cell membrane has the highest concentration of melatonin followed by mitochondria, nucleus, and cytos...