Journal ArticleDOI
Subneuronal Fate of Intracerebroventricular Injected 3H-Melatonin
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The fate of 3H‐melatonin after its intracerebroventricular administration was studied both in different brain regions and in subcellular fractions and the rate of disappearance from the brain was found to be multiphasic.Abstract:
The fate of 3H-melatonin after its intracerebroventricular administration was studied both in different brain regions and in subcellular fractions. The rate of disappearance of 3H-melatonin from the brain was found to be multiphasic. Forty-eight h after a 3H-melatonin injection, radioactivity was still present in the brain. Nonlinear regression analysis of the data confirmed a very rapid half-life component and (t1/2 = 3.04 min) a slower one (t1/2 = 36 min). We also found a much slower component (t1/2 = 24 h), however. Considerable metabolism of melatonin was detected since only 36.5% of administered radioactivity remained as melatonin at 45 min. The subcellular distribution of the radioactivity present in the brain at all times studied showed that a major proportion of the radioactivity remained in the cytosol and respectively decreasing proportions in the 900g pellet, mitochondrial pellet, and the microsomes. The radioactivity remaining in the cytosol at 45 min was found to coelute with a macromolecule that was resolved by gel filtration and could be displaced by previous melatonin administration. Purified nuclei retained 0.71% of the radioactivity at 45 min; of this total, 73% was KCl extractable. Our data suggest the presence of a binding site in the cytosol and in the nucleus. The presence of 3H-melatonin up to 48 h after its administration may account for melatonin's long-term effects on brain function.read more
Citations
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Journal ArticleDOI
Melatonin modifies calmodulin cell levels in MDCK and N1E-115 cell lines and inhibits phosphodiesterase activity in vitro.
TL;DR: One of the mechanisms of action of melatonin is a calmodulin-melatonin interaction, and the results point out that one of the reasons for the increased melatonin levels in cells cultured with 10(-9) M melatonin are Calmodulin levels.
Journal ArticleDOI
Melatonin from cerebrospinal fluid but not from blood reaches sheep cerebral tissues under physiological conditions.
TL;DR: Data is provided to support the hypothesis that, in sheep and possibly in humans, only the CSFMLT, and not the blood MLT, can provide most of MLT to the cerebral tissue in high concentrations, particularly in the periventricular area.
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Melatonin binding sites: Are they receptors?
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Pineal modulation of the rat caudate‐putamen spontaneous neuronal activity: Roles of melatonin and vasotocin
TL;DR: The results indicate that the pineal compounds melatonin and vasotocin are neuromodulators of spontaneous neuronal activity of the rat caudate‐putamen.
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Reciprocal effects of chronic diazepam and melatonin on brain melatonin and benzodiazepine binding sites
TL;DR: Results indicate benzodiazepine‐mediated suppression of brain melatonin binding sites that can be abrogated by melatonin administration.
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