title: Orally administered melatonin improves nocturnal rest in young and old ringdoves (Streptopelia risoria).
abstract: Melatonin possesses chronobiotic properties, which affects sleep/wake rhythms. We investigated a 7-day administration of melatonin (0.25, 2.5 and 5 mg/kg body weight) on the activity/rest rhythms of a diurnal animal (the ringdove, Streptopelia risoria), aged 2-3 (young) and 10-12 (old) years, and its possible relationship with the serum levels of melatonin and serotonin. Total nocturnal and diurnal activity pulses were logged at basal, during, and up to 7 days after the treatments. The animals received 0.1 ml of melatonin orally 1 hr before lights off. The results showed that the administration of whichever melatonin dose decreased both diurnal and nocturnal old ringdove activity, the reduction being larger at night. The young animals also reduced their nocturnal activity with all three melatonin concentrations, whereas their diurnal activity only decreased with the 2.5 and 5 mg/kg body weight treatments. We chose those treatments that gave the best results in terms of nocturnal rest and the least affected diurnal activity (0.25 mg/kg body weight and 2.5 mg/kg in the young and old animals, respectively). Serum melatonin was measured by radioimmunoassay and serotonin by ELISA. In both age groups, the treatment increased both nocturnal and diurnal melatonin levels, with the effect continuing until 1 day after the last dose. Serum serotonin levels were unaffected by the treatments in either age group. The treatment restored the amplitude of the serum melatonin rhythm in the old animals to that of the young group. In summary, treatment with melatonin may be appropriate to improve nocturnal rest, and beneficial as a therapy for sleep disorders.
authors: Department of Physiology, Faculty of Science, University of Extremadura, Badajoz, Spain.
authors: Sergio D
authors: SD
authors: Paredes
authors: Maria Pilar
authors: MP
authors: Terrón
authors: Vicente
authors: V
authors: Valero
authors: Carmen
authors: C
authors: Barriga
authors: Russel J
authors: RJ
authors: Reiter
authors: Ana B
authors: AB
authors: Rodríguez
mesh_terms: D000204:Activity Cycles / Q000187:drug effects* / Q000502:physiology; D000284:Administration, Oral; D000367:Age Factors; D000375:Aging / Q000502:physiology; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology; D010856:Columbidae / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D012701:Serotonin / Q000097:blood; D013997:Time Factors
chemical_list: D000975:Antioxidants; D012701:Serotonin; D008550:Melatonin