Comparative Study of the Activity/Rest Rhythms in Young and Old Ringdove (Streptopelia Risoria): Correlation with Serum Levels of Melatonin and Serotonin

Abstract

Aging is characterized by changes in the circadian rhythms of melatonin, serotonin, and sleep/wakefulness, alterations that affect sleep quality. The authors studied the circadian rhythms of serotonin and melatonin in young and old ringdoves (Streptopelia risoria) (2-3 and 10-12 yrs old, respectively), animals that are characterized by being monophasic and active by day, like humans. The aim was to correlate the indole rhythms with the animals' activity/rest periods. The animals were kept under a 12:12 h light/dark cycle, fed ad libitum, and housed in separate cages equipped for activity recording. Activity pulses were recorded with one actometer per animal (two perpendicular infrared transmitters) and were logged every 15 min by a computer program (DAS 16) throughout the experiment. Melatonin was measured by radioimmunoassay and serotonin by ELISA at intervals of 3 h (from 09:00 to 18:00 h) and 1 h (from 21:00 to 06:00 h), respectively. The results showed a reduction in nocturnal vs. diurnal activity of 89% and 61% in the young and old animals, respectively, with 100% considered to be the diurnal activity of each group. The amplitude of a cosine function fit to the melatonin concentrations of the old animals was half that of the young birds. The acrophase and nadir were at 02:00 and 14:00 h in the young and 01:00 and 13:00 h in the old animals, respectively. The amplitude of the corresponding cosine function fit to the serotonin concentrations in the old birds was one-third that of the young animals. The acrophase and nadir were at 15:00 and 03:00 h in the young and 16:00 and 04:00 h in the old animals, respectively. For both melatonin and serotonin, the concentrations in the young animals were significantly higher than in the old at most of the measurement times. There was a clear negative correlation between the circadian rhythms of activity and the serum melatonin levels in both young and old animals. The equivalent correlation for serotonin was positive, and stronger in the case of the young animals. The results suggest a possible relationship between the observed decline in the amplitude of the old animals' melatonin and serotonin rhythms and the lower percentage reduction in their nocturnal relative to diurnal activity pulses compared to the young animals. In conclusion, the circadian rhythms of melatonin and serotonin undergo alterations with age that could be involved in the changes in age-associated sleep.

Sleep and Development in Genetically Tractable Model Organisms

“…This maturation of sleep characteristics as an organism develops from embryo to mature adult is referred to as sleep ontogeny or ontogenetic sleep changes. Similar trends, where the amount of total sleep, or vertebrate REM sleep, is highest early in development, have been observed in mammals, fish, birds, insects, and nematodes (Jouvet-Mounier et al 1970;McGinty et al 1977;Szymczak 1987;Shaw et al 2000;Kirov and Moyanova 2002;Paredes et al 2006;Raizen et al 2008;Hasan et al 2012;Todd et al 2012;Sorribes 2013). These findings led to the hypothesis that during early life, REM sleep and invertebrate sleep may play an important role in the development of the nervous system, by establishing a period of globally heightened plasticity and/ or providing endogenous, specialized activity in certain neural circuits (O'Donovan 1999;Blumberg 2008, 2010;Blumberg et al 2013;Corner 2013).…”

Either taking it easy or feeling too tired: old Cory’s Shearwaters display reduced activity levels while at sea

“…It seems less likely that Old birds sleep more during darkness, as sleep is more often interrupted in aged animals (e.g. Hornung et al 2005), including birds (Paredes et al 2006). That sea surface temperatures in feeding areas and foraging trip duration were similar in Mid-aged and Old individuals suggests that differences in activity levels between age groups cannot be explained by disparate habitat preferences.…”

Melatonin and tryptophan counteract lipid peroxidation and modulate superoxide dismutase activity in ringdove heterophils in vivo. Effect of antigen-induced activation and age

“…The age-related decline in both circulating levels and the amplitude of the rhythm of melatonin are welldocumented phenomena in a variety of species (Lahiri et al 2004;Pang et al 1990), including the ringdove (Paredes et al 2006(Paredes et al , 2007c. The loss of this potent anti-oxidant during aging may be, in part, the cause of the onset of the age-related imbalance between prooxidants and antioxidants.…”

“…Based on previous research, the acrophases of the melatonin rhythm in the basal groups were established at 0200 hours and 0100 hours, and the nadirs at 1400 and 1300 hours, in young and old ringdoves, respectively (Paredes et al 2006). In the melatonin-treated birds, the acrophases and nadirs were established at 0230 hours and 1430 hours, and 0300 hours and 1500 hours in young and old animals, respectively (Paredes et al 2007d).…”

“…This is accompanied by significantly lowered circulating serotonin levels, impairments in the activity/rest and core and peripheral temperature rhythms (Paredes et al 2006(Paredes et al , 2007c2009a), as well as alterations in heterophil function (Paredes et al 2007a, b) and elevated cytokine serum levels (Paredes et al 2009a).…”