title: Rest-activity circadian rhythms in aged Nothobranchius korthausae. The effects of melatonin.
abstract: Adult (48-week-old) and senescent (72-week-old) individually-kept Nothobranchius korthausae were used as experimental subjects to characterise circadian system (CS) function and age-related changes in senescent fish. This species was specifically chosen because it has already shown potential for use as a model system in gerontological studies. The rest-activity rhythm (RAR) in fish can be easily monitored and used to characterise the state of the CS, and it has also been proposed as a reliable model to study sleep-like periods in fish. As they aged, N. korthausae experienced a significant decrease in total daily activity and a progressive impairment of the RAR, accompanied by changes in the regularity, fragmentation and amplitude of the rhythm. The ability of the CS to oscillate autonomously when the two main synchronizers, photoperiod and feeding time, were absent (continuous darkness and random feeding), was also impaired with age, as the capacity to re-synchronise to the light-dark (LD) cycle declined. Melatonin treatment improved the regularity, fragmentation and amplitude of the RAR in senescent fish, and it also improved sleep efficiency. In conclusion, N. korthausae represents a viable model for studying the aging of the circadian system and the restorative effect of chronobiotic substances, such as melatonin.
authors: Department of Physiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain. alucas@um.es
authors: Alejandro
authors: A
authors: Lucas-Sánchez
authors: Pedro Francisco
authors: PF
authors: Almaida-Pagán
authors: Antonio
authors: A
authors: Martinez-Nicolas
authors: Juan Antonio
authors: JA
authors: Madrid
authors: Pilar
authors: P
authors: Mendiola
authors: Jorge
authors: J
authors: de Costa
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D021081:Chronobiology Disorders / Q000188:drug therapy* / Q000503:physiopathology; D002940:Circadian Rhythm / Q000187:drug effects / Q000502:physiology*; D003532:Cyprinodontiformes / Q000502:physiology*; D018450:Disease Progression; D004353:Drug Evaluation, Preclinical / Q000379:methods; D005247:Feeding Behavior / Q000502:physiology; D008297:Male; D008550:Melatonin / Q000494:pharmacology / Q000627:therapeutic use*; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D017440:Photoperiod; D012146:Rest / Q000502:physiology; D012890:Sleep / Q000187:drug effects / Q000502:physiology
chemical_list: D008550:Melatonin