Melatonin physiological effects

Recent studies in a model of ischemic stroke suggest that the acute neuro-protective effect of melatonin involves activation of the phosphatidylinositol-3-kinase/Akt pathway, whereas ERK-1/2 and c-Jun N-terminal kinase-1/2, in addition to Akt signaling, appear to be involved in its long-term effects (Kilic et al. 2005). These results indicate that melatonin can interact with multiple cellular pathways to produce its diverse physiological effects. Moreover, MTi and MT2 receptors can interact with divergent signaling pathways, as shown by their ability to... 

HT modulates neuroendocrine function 239 5-HT modulates circadian rhythmicity 239 5-HT modulates feeding behavior and food intake 239 Not only does 5-HT have important physiological effects of its own but it is also the precursor of the hormone melatonin 240... 

Melatonin is found in the pineal gland (= epiphysis) in high concentrations. As is evident from the formula, it is an indole derivative which probably arises from tryptophan and is closely related to serotonin (cf. Section 12). Melatonin blanches amphibial skin it is the melanophore-contracting principle (the antagonist of melanotropin. Section 9). No other physiological effects of this substance, which was isolated only recently, are known. 

Tenn, C. Niles, L. P. (1993). Physiological regulation of melatonin receptors in rat suprachiasmatic nuclei diurnal rhythmicity and effects of stress. Mol. Cell. Endocrinol. 98, 43-8. 

Most attempts of using hormones as psychotropic medications were conducted with gonadal or with thyroid hormones, mainly because of the apparent mood changes associated with physiological or disorder-associated changes in levels or activity of these hormones. However, as shown in Table 17-1, current applications are broader and involve several hormones and systems. It is anticipated that, with acquired knowledge on mood effects of several other hormones, that list will continue to expand. Here, I focus on psychotropic effects of gonadal and thyroid hormones. Cortisol and melatonin are only briefly discussed. 

In recent years, many physiological properties of melatonin have been described resulting in much attention in the development of synthetic compounds possessing indole ring [94]. These compounds have structural similarity to melatonin. However, the therapy of oxidative stress-related diseases has not found satisfactory application in clinical practice. This may be due to the insufficient efficacy of drugs available, their unsuitable pharmacokinetics, side effects, and toxicity. 

Environmental magnetic fields (1.2 pT, 60 Hz) significantly reduce the inhibitory action of physiological levels of the hormone melatonin on the growth of human breast cancer cells in vitro. A similar inhibitory effect is... 

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