title: Intake of melatonin increases tryptophan hydroxylase type 1 activity in aged rats: Preliminary study.
abstract: Pineal melatonin is important not only for synchronization of biological rhythms, but also in the ageing process as a potential drug to relieve oxidative damage. During ageing, the nocturnal melatonin production decreases resulting in an increased incidence of disorders. Present in vivo experiments were performed to study the effects of exogenous melatonin chronically administered to old rats on the pineal biosynthesis of melatonin and the precursor serotonin (5-HT) mediated by tryptophan hydroxylase type 1 (TPH-1). Accumulation of 5-hydroxytryptophan (5-HTP) after decarboxylase inhibition was used as a measure of the TPH-1 activity. 5-HT and its metabolite 5-HIAA were also quantified by HPLC-ED. As expected, ageing resulted in worsening of different neurochemical parameters. However, chronic intake of melatonin (1mg/kg/day, diluted in drinking water, 4 weeks) increased TPH-1 activity and significantly improved the age-induced deficits in nocturnal melatonin content in the pineal gland. Results suggest that melatonin intake (or melatonin rich foods) may contribute to recover the pineal function preventing the nocturnal descent of 5-HT and melatonin biosynthesis that normally occur in pineal gland as a consequence of ageing.
authors.affiliation: Laboratorio de Fisiología, Departamento de Biología, Universitat de les Illes Balears (UIB), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain; Fundación Investigación Sanitaria Illes Balears (FISIB), Hospital Universitario Son Espases, Mallorca, Spain. Electronic address: david.moranta@caubet-cimera.es.
authors.forename: D
authors.initials: D
authors.lastname: Moranta
authors.affiliation: Laboratorio de Fisiología, Departamento de Biología, Universitat de les Illes Balears (UIB), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain. Electronic address: pere.barcelo@uib.es.
authors.forename: P
authors.initials: P
authors.lastname: Barceló
authors.affiliation: Laboratorio de Fisiología, Departamento de Biología, Universitat de les Illes Balears (UIB), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain. Electronic address: sara.aparicio@alvarez.es.
authors.forename: S
authors.initials: S
authors.lastname: Aparicio
authors.affiliation: Department of Pharmaceutical Sciences, University of California, Irvine, CA, USA. Electronic address: cgarauga@uci.edu.
authors.forename: C
authors.initials: C
authors.lastname: Garau
authors.affiliation: Laboratorio de Fisiología, Departamento de Biología, Universitat de les Illes Balears (UIB), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain. Electronic address: fioresarubbo@hotmail.com.
authors.forename: F
authors.initials: F
authors.lastname: Sarubbo
authors.affiliation: Laboratorio de Fisiología, Departamento de Biología, Universitat de les Illes Balears (UIB), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain. Electronic address: margaramis87@hotmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Ramis
authors.affiliation: Laboratorio de Fisiología, Departamento de Biología, Universitat de les Illes Balears (UIB), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain. Electronic address: cristina.nicolau@uib.es.
authors.forename: C
authors.initials: C
authors.lastname: Nicolau
authors.affiliation: Laboratorio de Fisiología, Departamento de Biología, Universitat de les Illes Balears (UIB), Cra. Valldemossa km 7.5, E-07122 Palma de Mallorca, Spain. Electronic address: susana.esteban@uib.es.
authors.forename: S
authors.initials: S
authors.lastname: Esteban
mesh_terms: D000375:Aging / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology; D004334:Drug Administration Schedule; D004353:Drug Evaluation, Preclinical / Q000379:methods; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000096:biosynthesis / Q000494:pharmacology*; D010870:Pineal Gland / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000096:biosynthesis; D014365:Tryptophan Hydroxylase / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000975:Antioxidants; D012701:Serotonin; D014365:Tryptophan Hydroxylase; C504570:tph1 protein, rat; D008550:Melatonin
keywords: 5-HT; Ageing; Melatonin; Pineal gland; Tryptophan hydroxylase type 1