Splenic hypertrophy and extramedullary hematopoiesis induced in male Syrian hamsters by short photoperiod or melatonin injections and reversed by melatonin pellets or pinealectomy

Vaughan, Mary K.; Hubbard, Gene B.; Champney, Thomas H.; Vaughan, George M.; Little, John C.; Reiter, R. J.

doi:10.1002/aja.1001790205

Cited by 62 publications

(28 citation statements)

References 20 publications

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“…Here the artificial shortening of day lengths or alternatively melatonin injections induce an increase in thymus weight [49] and spleen hypertrophy [50], implying a melatonin-mediated photoperiodic effect on the immune system. Furthermore, it was demonstrated that melatonin controls diurnal and seasonal rhythms of leukocyte proliferation [51], of cytokine production [44,45] and NK cell activity [52] in mammalian bone marrow cells.…”

Section: Neuro-endocrine Melatonin: Systemic Effects Of Pineal Melatomentioning

confidence: 98%

Melatonin: A pleiotropic molecule regulating inflammation

Radogna

Diederich

Ghibelli

2010

Biochemical Pharmacology

308

247

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Melatonin is a neurohormone produced by the pineal gland that regulates sleep and circadian functions. Melatonin also regulates inflammatory and immune processes acting as both an activator and inhibitor of these responses. Melatonin demonstrates endocrine, but also paracrine and autocrine effects in the leukocyte compartment: on one side, leukocytes respond to melatonin in a circadian fashion; on the other side, leukocytes are able to synthesize melatonin by themselves.With its endocrine and paracrine effects, melatonin differentially modulates pro-inflammatory enzymes, controls production of inflammatory mediators such as cytokines and leukotrienes and regulates the lifespan of leukocytes by interfering with apoptotic processes. Moreover, its potent anti-oxidant ability allows scavenging of oxidative stress in the inflamed tissues. The interesting timing of pro-and anti-inflammatory effects, such as those affecting lipoxygenase activity, suggests that melatonin might promote early phases of inflammation on one hand and contribute to its attenuation on the other hand, in order to avoid complications of chronic inflammation. This review aims at giving a comprehensive overview of the various inflammatory pathways regulated by this pleiotropic hormone.

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Section: Neuro-endocrine Melatonin: Systemic Effects Of Pineal Melatomentioning

confidence: 98%

Melatonin: A pleiotropic molecule regulating inflammation

Radogna

Diederich

Ghibelli

2010

Biochemical Pharmacology

308

247

View full text Add to dashboard Cite

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“…Melatonin treatment affects the reproductive capacity, the production of sex hormones, and certain immune functions [47, 48], suggesting the involvement of the hypothalamus-pituitary axis in these responses. However, in our study we did not find significant differences between the responses to treatment in girls and boys, discarding a sex-dependent effect of the immunotherapy.…”

Section: Discussionmentioning

confidence: 99%

Melatonin and β-Endorphin Changes in Children Sensitized to Olive and Grass Pollen after Treatment with Specific Immunotherapy

Girón-Caro

Muñóz-Hoyos²,

Ruiz-Cosano³

et al. 2001

Int Arch Allergy Immunol

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Background: Specific immunotherapy for respiratory allergy, a seasonal disease, significantly reduces the inflammatory process, attenuating the clinical symptoms. The mechanism for the clinical beneficial effect of immunotherapy has not yet been clarified. Melatonin shows a circadian and seasonal variation and together with the endogenous opioid system plays an immunomodulatory role acting on both specific and nonspecific immunity responses. Thus, the possibility that immunotherapy involved changes in the melatonin-opioid system was investigated. Methods: Thirty-five children aged 3–15 years with rhinitis and asthma due to olive + grass pollen sensitization were studied. The patients were treated with depot extracts containing the identified allergens with increasing doses from 1 to 1,000 IU/ml during 3 months. Melatonin, β-endorphin, total and specific IgE and IgG4 were determined before and after treatment. Results: All children showed a significant improvement of their symptoms at the end of the treatment, coinciding with a significant drop of both melatonin and β-endorphin levels. Total IgE decreased in most of the cases although the mean values did not show significant changes. Specific IgE and IgG4 were also unchanged. A significant correlation between melatonin and β-endorphin and between β-endorphin and IgG4 was found before immunotherapy, and these correlations disappeared when the treatment was finished. Conclusions: The decrease in the levels of melatonin and β-endorphin suggests the disappearance of their stimulating influence on the immune system. Thus, hyposensitization after immunotherapy may involve, at least in part, the inhibition of the immunoenhancing properties of the melatonin-opioid system.

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“…Taken together, melatonin appears to coordinate many seasonal and daily changes in energy use and energy conservation [70] [111,114] [ 144] and Syrian hamsters (Mesocricetus auratus) [25]. Splenic masses, total splenic lymphocyte numbers and macrophage counts were significantly higher in hamsters exposed to short photoperiod as compared to animals exposed to long photoperiod [25,142]. Photoperiod did not affect thymic weight or antibody production in hamsters [24] [ 14].…”

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confidence: 99%