| Daily variation of constitutively activated nuclear factor kappa B (NFKB) in rat pineal gland. | |
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MedLine Citation:
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PMID: 20205557 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In mammals, the production of melatonin by the pineal gland is mainly controlled by the suprachiasmatic nuclei (SCN), the master clock of the circadian system. We have previously shown that agents involved in inflammatory responses, such as cytokines and corticosterone, modulate pineal melatonin synthesis. The nuclear transcription factor NFKB, detected by our group in the rat pineal gland, modulates this effect. Here, we evaluated a putative constitutive role for the pineal gland NFKB pathway. Male rats were kept under 12 h:12 h light-dark (LD) cycle or under constant darkness (DD) condition. Nuclear NFKB was quantified by electrophoretic mobility shift assay on pineal glands obtained from animals killed throughout the day at different times. Nuclear content of NFKB presented a daily rhythm only in LD-entrained animals. During the light phase, the amount of NFKB increased continuously, and a sharp drop occurred when lights were turned off. Animals maintained in a constant light environment until ZT 18 showed diurnal levels of nuclear NFKB at ZT15 and ZT18. Propranolol (20 mg/kg, i.p., ZT 11) treatment, which inhibits nocturnal sympathetic input, impaired nocturnal decrease of NFKB only at ZT18. A similar effect was observed in free-running animals, which secreted less nocturnal melatonin. Because melatonin reduces constitutive NFKB activation in cultured pineal glands, we propose that this indolamine regulates this transcription factor pathway in the rat pineal gland, but not at the LD transition. The controversial results regarding the inhibition of pineal function by constant light or blocking sympathetic neurotransmission are discussed according to the hypothesis that the prompt effect of lights-off is not mediated by noradrenaline, which otherwise contributes to maintaining low levels of nuclear NFKB at night. In summary, we report here a novel transcription factor in the pineal gland, which exhibits a constitutive rhythm dependent on environmental photic information. |
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Authors:
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Erika Cecon; Pedro A Fernandes; Luciana Pinato; Zulma S Ferreira; Regina P Markus |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Chronobiology international Volume: 27 ISSN: 1525-6073 ISO Abbreviation: Chronobiol. Int. Publication Date: 2010 Jan |
Date Detail:
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Created Date: 2010-03-08 Completed Date: 2010-05-25 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8501362 Medline TA: Chronobiol Int Country: England |
Other Details:
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Languages: eng Pagination: 52-67 Citation Subset: IM |
Affiliation:
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Laboratory of Chronopharmacology, Department of Physiology, Institute of Bioscience, University of S?o Paulo, CEP: 05508-900, S?o Paulo, Brazil. |
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Base Sequence Cell Nucleus / metabolism Circadian Rhythm / genetics, physiology* Male Melatonin / biosynthesis, blood NF-kappa B / chemistry, genetics, metabolism* NF-kappa B p50 Subunit / metabolism Oligonucleotide Probes / genetics Photoperiod Pineal Gland / metabolism* Protein Subunits Rats Rats, Wistar Transcription Factor RelA / metabolism |
| Chemical | |
Reg. No./Substance:
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0/NF-kappa B; 0/NF-kappa B p50 Subunit; 0/Oligonucleotide Probes; 0/Protein Subunits; 0/Rela protein, rat; 0/Transcription Factor RelA; 73-31-4/Melatonin |
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