title: Local corticosterone infusion enhances nocturnal pineal melatonin production in vivo.
abstract: Melatonin, an important marker of the endogenous rhythmicity in mammals, also plays a role in the body defence against pathogens and injuries. In vitro experiments have shown that either pro- or anti-inflammatory agents, acting directly in the organ, are able to change noradrenaline-induced pineal indoleamine production. Whereas corticosterone potentiates melatonin production, incubation of the gland with tumour necrosis factor-alpha decreases pineal hormonal production. In the present study, we show that nocturnal melatonin production measured by intra-pineal microdialysis is enhanced in pineals perfused with corticosterone at concentrations similar to those measured in inflamed animals. In vitro experiments suggest that this enhancement may be due to an increase in the activity of the two enzymes that convert serotonin to N-acetylserotonin (NAS) and NAS to melatonin. The present results support the hypothesis that the pineal gland is a sensor of inflammation mediators and that it plays a central role in the control of the inflammatory response.
authors.affiliation: Laboratório de Cronofarmacologia, Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil. pacmf2001@gmail.com
authors.forename: P A C M
authors.initials: PA
authors.lastname: Fernandes
authors.forename: B
authors.initials: B
authors.lastname: Bothorel
authors.forename: D
authors.initials: D
authors.lastname: Clesse
authors.forename: A W A
authors.initials: AW
authors.lastname: Monteiro
authors.forename: C
authors.initials: C
authors.lastname: Calgari
authors.forename: S
authors.initials: S
authors.lastname: Raison
authors.forename: V
authors.initials: V
authors.lastname: Simonneaux
authors.forename: R P
authors.initials: RP
authors.lastname: Markus
mesh_terms: D000121:Acetylserotonin O-Methyltransferase / Q000378:metabolism; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000818:Animals; D047068:Arylalkylamine N-Acetyltransferase / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology; D003345:Corticosterone / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D008297:Male; D008550:Melatonin / Q000096:biosynthesis*; D017551:Microdialysis; D009638:Norepinephrine / Q000494:pharmacology; D017440:Photoperiod; D010870:Pineal Gland / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D046509:Tissue Culture Techniques; D014365:Tryptophan Hydroxylase / Q000378:metabolism
chemical_list: D000316:Adrenergic alpha-Agonists; D014365:Tryptophan Hydroxylase; D000121:Acetylserotonin O-Methyltransferase; D047068:Arylalkylamine N-Acetyltransferase; D008550:Melatonin; D003345:Corticosterone; D009638:Norepinephrine