Persistence of circadian oscillation while locomotor activity and plasma melatonin levels became aperiodic under prolonged continuous light in the rat

Honma, Sato; Kanematsu, Nobue; Katsuno, Yumiko; Honma, Ken‐ichi

doi:10.1016/0304-3940(96)13006-8

Cited by 23 publications

(10 citation statements)

References 16 publications

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“…Constant light provokes the loss of circadian rhythmicity in adult rats in some variables such as motor activity (9,15,18). However, in past experiments we observed that adult rats exhibited a circadian rhythm of motor activity under LL if previously subjected to LL throughout their entire lactation period (5-7).…”

Section: Discussionmentioning

confidence: 94%

“…However, under constant bright light (LL), the circadian rhythm of most animals is not that established, because splitting (4,8) and many ultradian components in the pattern of motor activity rhythm appear. In rats, after a long exposure to LL, the circadian periodicity disappears, as do rhythms of motor activity (9,15,18), plasma melatonin (18), sexual hormones (34), and body temperature (9,11,15).…”

Section: Development; Motor Activitymentioning

confidence: 99%

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Bright light during lactation alters the functioning of the circadian system of adult rats

Canal-Corretger

Cambras

Vilaplana

et al. 2000

American Journal of Physiology-Regulatory, Integrative and Comp

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To examine the role of light in the maturation of the circadian pacemaker, twelve groups of rats were raised in different conditions of exposure to constant bright light (LL) during lactation: both duration and timing of LL were varied. We studied the motor activity rhythm of the rats after weaning, first under LL and then under constant darkness (DD). In DD, two light pulses [at circadian time 15 (CT15) and CT22] were applied to test the response of the pacemaker. Greater exposure to LL days during lactation increased the number of rhythmic animals and the amplitude of their motor activity rhythm in the LL stage and decreased the phase delay due to the light pulse at CT15. The timing of LL during lactation affected these variables too. Because the response of the adult to light depended on both the number and timing of LL days during lactation, the exposure to light at early stages may influence the development of the circadian system by modifying it structurally or functionally.

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Section: Discussionmentioning

confidence: 94%

Section: Development; Motor Activitymentioning

confidence: 99%

Bright light during lactation alters the functioning of the circadian system of adult rats

Canal-Corretger

Cambras

Vilaplana

et al. 2000

American Journal of Physiology-Regulatory, Integrative and Comp

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“…These differentially synchronize the two putative oscillators of the circadian pacemaker, "M" (morning) and "E" (evening), which are considered responsible for the cessation and onset respectively of the motor activity peak [2,12,17,18,19,29]. The direction (symmetrical or asymmetrical) of the extension of the dark phase is known to have differential effects on the onset and cessation of the activity span, the melatonin peak and pineal N-acetyl transferase activity in hamsters and rats [9,11,26,41]. It was not known, however, how an asymmetrical extension of darkness by a 6-h delay in the light signal would affect body temperature and motor activity rhythms in young or old rats.…”

Section: Discussionmentioning

confidence: 99%

“…LL [3,10,11] or DD [3]. The circadian rhythm of body temperature is generated by an endogenous component but is also dependent on motor activity [20,22,26].…”

Section: Introductionmentioning

confidence: 99%

Effect of a short photoperiod on circadian rhythms of body temperature and motor activity in old rats

Benstaali¹,

Bogdan²,

Touitou³

2002

Pflügers Arch - Eur J Physiol

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Circadian rhythms of body temperature and motor activity were documented in young and old rats (four 8-week-old and five 22-month-old male Wistars, implanted with telemetric probes and housed in a chronobiological facility) under two different photoperiod conditions. The animals were maintained in a light:dark (LD) cycle of 12 h each (LD 12:12) for 4 weeks and then exposed to a LD 6:18 cycle for 7 weeks to assess the effect of age on the desynchronization of the temporal structure of the rhythms. In old rats under LD 12:12, the power of the 24-h component and the circadian amplitude of body temperature and motor activity were markedly lower than in the young and both rhythms were phase-advanced. After the shift to LD 6:18, the circadian rhythmicity was maintained for both variables and the same phase delay (+5+/-1 h) was observed in both age groups, as was a gradual expansion of the patterns of both functions with the longer night. The photoperiod reduction (6 weeks under LD 6:18) did not modify the power of the 24-h component of body temperature and motor activity in old rats. In young rats, however, the power and amplitude of the 24-h component of motor activity rhythm fell to the levels of those in old rats, while the power of the 24-h component of body temperature rhythm and the amplitude did not change. Our data show that the circadian rhythm of motor activity, but not of body temperature, responds age dependently to a photoperiod reduction.

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“…Exposure of adults to LL results in the loss of the circadian rhythms of locomotor activity [58], [59], [60], plasma melatonin [60], sex hormones [61] and body temperature [58], [59], which correspond with weakened or lost oscillations in the SCN [56], both at the neuronal (firing rate [62]) and molecular clock levels (expression of mPER2 clock protein [63]). The cause of this decline in circadian amplitude at the tissue and electrical activity levels appears to be a decrease in SCN cell population synchronization rather than an impairment of the individual SCN cell rhythm-generating ability [64].…”

Section: Discussionmentioning

confidence: 99%

Programming of Mice Circadian Photic Responses by Postnatal Light Environment

2014

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Early life programming has important consequences for future health and wellbeing. A key new aspect is the impact of perinatal light on the circadian system. Postnatal light environment will program circadian behavior, together with cell morphology and clock gene function within the suprachiasmatic nucleus (SCN) of the hypothalamus, the principal circadian clock in mammals. Nevertheless, it is still not clear whether the observed changes reflect a processing of an altered photic input from the retina, rather than an imprinting of the intrinsic molecular clock mechanisms. Here, we addressed the issue by systematically probing the mouse circadian system at various levels. Firstly, we used electroretinography, pupillometry and histology protocols to show that gross retinal function and morphology in the adult are largely independent of postnatal light experiences that modulate circadian photosensitivity. Secondly, we used circadian activity protocols to show that only the animal's behavioral responses to chronic light exposure, but not to constant darkness or the acute responses to a light stimulus depend on postnatal light experience. Thirdly, we used real-time PER2::LUC rhythm recording to show long-term changes in clock gene expression in the SCN, but also heart, lung and spleen. The data showed that perinatal light mainly targets the long-term adaptive responses of the circadian clock to environmental light, rather than the retina or intrinsic clock mechanisms. Finally, we found long-term effects on circadian peripheral clocks, suggesting far-reaching consequences for the animal's overall physiology.

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Persistence of circadian oscillation while locomotor activity and plasma melatonin levels became aperiodic under prolonged continuous light in the rat

Cited by 23 publications

References 16 publications

Bright light during lactation alters the functioning of the circadian system of adult rats

Bright light during lactation alters the functioning of the circadian system of adult rats

Effect of a short photoperiod on circadian rhythms of body temperature and motor activity in old rats

Programming of Mice Circadian Photic Responses by Postnatal Light Environment

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