Photoperiodic control of circadian activity rhythms in diurnal rodents

Kramm, Kenneth R.; Kramm, Deborah A.

doi:10.1007/bf02245543

Cited by 28 publications

(16 citation statements)

References 27 publications

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“…Thus, τ lengthens in response to light at the circadian phase, where delay shifts are maximal, and shortens at the circadian phase, where phase shifts are minimal. This association has been observed in other mammals before Kramm and Kramm, 1980;Gerkema et al, 1993;Beersma et al, 1999a;Weinert and Kompauerova, 1998). It demonstrates that the single instantaneous phase shift is part of a more long-term response, which has a clear function in eventually making the system run on a period more closely matching that of its zeitgeber, so that less corrective resetting is required day after day (Beersma et al, 1999a).…”

Section: Period Response Curvessupporting

confidence: 76%

Phase and Period Responses of the Circadian System of Mice (Mus musculus) to Light Stimuli of Different Duration

Comas

Beersma²,

Spoelstra³

et al. 2006

J Biol Rhythms

147

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Phase and period responses of the circadian system of mice (Mus musculus) to light stimuli of different duration Comas, M.; Beersma, D. G. M.; Spoelstra, K.; Daan, S. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. In nature, virtually all circadian rhythms assume the 24.0-h period of the solar day-night cycle. This is due to the entrainment of the endogenous oscillators to the external light-dark cycle, the dominant zeitgeber for the majority of organisms. The process of entrainment is based on differential phase and period responses of the circadian systems to light depending on the phase at which the stimulus is applied. The (1, 3, 4, 6, 9, 12, and 18 h) given once per 11 days in otherwise constant darkness. Light-pulse duration affected both amplitude and shape of the phase response curve. Nine-hour light pulses yielded the maximal amplitude PRC. As in other systems, the circadian period slightly lengthened following delays and shortened following advances. The authors aimed to understand how different parts of the light signal contribute to the eventual phase shift. When PRCs were plotted using the onset, midpoint, and end of the pulse as a phase reference, they corresponded best with each other when using the mid-pulse. Using a simple phase-only model, the authors explored the possibility that light affects oscillator velocity strongly in the 1st hour and at reduced strength in later hours of the pulse due to photoreceptor adaptation. They fitted models based on the 1-h PRC to the data for all light pulses. The best overall correspondence between PRCs was obtained when the effect of light during all hours after the first was reduced by a factor of 0.22 relative to the 1st hour. For the predicted PRCs, the light action centered on average at 38% of the light pulse. This is close to the reference phase yielding best correspondence at 36% of the pulses. The result is thus compatible with an initial major contribution of the onset of the light pulse followed by a reduced effect of light responsible for the differences between PRCs for different duration pulses. The authors suggest that the mid-pulse is a better phase reference than lights-on to plot and compare PRCs of different light-pulse durations.

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Section: Period Response Curvessupporting

confidence: 76%

Phase and Period Responses of the Circadian System of Mice (Mus musculus) to Light Stimuli of Different Duration

Comas

Beersma²,

Spoelstra³

et al. 2006

J Biol Rhythms

147

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“…In several diumal mammals (Ammospermophilus leucurus, Tamias striatus, and Tamiasciurus hudsonicus), light-pulse presentations at the end of the subjective night produce phase advances of the free-running rhythm (Kramm, 1975(Kramm, , 1976Kramm and Kramm, 1980;Pohl, 1983 (open circles) as averaged over 2-hr bins of phase relationships between the two. a substantial phase shift in the activity rhythm.…”

Section: Discussionmentioning

confidence: 99%

The Two-Oscillator Circadian System of Tree Shrews (Tupaia belangeri) and Its Response to Light and Dark Pulses

Meijer

Daan²,

Overkamp

et al. 1990

J Biol Rhythms

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The wheel-running activity rhythm of tree shrews (tupaias; Tupaia belangeri) housed in constant darkness (DD) phase-advanced following a 3-hr light pulse at circadian time (CT) 21. Dark pulses of 3 hr presented to tupaias in bright constant light (LL) did not induce significant phase shifts of the free-running activity rhythm, irrespective of the CT. In dim LL, tupaias showed simultaneous splitting of their circadian rhythm of wheel-running activity, nest-box activity, and feeding behavior. Light pulses of 6 hr and 2300 lux were presented to 13 tupaias with split wheel-running activity rhythms. These light pulses induced immediate phase shifts in the two components of the split rhythm in opposite directions. No differences were observed between the light-pulse phase response curves of the two components. Equally large immediate phase advances were induced in both components by light pulses of 230 lux, but not by 23 lux. The final phase shifts were small at all CTs. In two tupaias, activity rhythms transiently split and re-fused. Analysis of the relative position of the components in one of these indicates asymmetry in the coupling between the components.

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“…Ambient temperatures have a considerable influence on farm animals, causing changes in feed intake, metabolism and heat balance (Fuquay 1981;Johnson 1980;Ronchi et al , 2001. Moreover, heat stress can affect the nutrition of animals by altering the dynamic characteristics of the digestion processes (Beede and Collier 1986).…”

Section: Introductionmentioning

confidence: 99%

Influence of different periods of exposure to hot environment on rumen function and diet digestibility in sheep

et al. 2009

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Effects of different periods of exposure to hot environments on rumen function, diet digestibility and digesta passage rate were studied in four adult not-pregnant Sardinian ewes housed in a climatic chamber. The ewes were kept in individual metabolic cages. The trial lasted 83 days; 17 days were spent under thermal comfort conditions (TC) [temperature-humidity index (THI) = 65.0 +/- 2.0], followed by 49 days under elevated THI (ETHI: THI = 82.0 +/- 2.5) and 17 days under thermal comfort (TC; THI = 65.0 +/- 1.0). Five digestibility and passage rate trials were carried out during the 83 days. Trials 1 and 5 were carried out under TC; trials 2, 3 and 4 were carried out under ETHI. Values of rectal temperatures (39.7 +/- 0.3 degrees C) and respiratory rate (118.4 +/- 31.8 breaths/min) indicated that sheep under ETHI were heat-stressed. Heat stress caused an increase (P < 0.01) in water intake, and reductions (P < 0.05) in dry matter intake, rumen pH, rumen cellulolytic and amylolytic bacteria count, rumen osmolarity, organic matter, dry matter, neutral detergent fibre, acid detergent fibre and non-structural carbohydrates digestibility coefficients, and a reduction of digesta passage rates. Under ETHI, diet digestibility and passage rate of digesta were reduced in a time-dependent fashion. Variation of diet digestibility under ETHI was not related to passage rate of digesta and feed intake. Reduction of cellulolytic and amylolytic bacteria and the adaptive response to hot environment seem to be related to alteration of digestibility observed in ewes chronically exposed to hot environment.

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Photoperiodic control of circadian activity rhythms in diurnal rodents

Cited by 28 publications

References 27 publications

Phase and Period Responses of the Circadian System of Mice (Mus musculus) to Light Stimuli of Different Duration

Phase and Period Responses of the Circadian System of Mice (Mus musculus) to Light Stimuli of Different Duration

The Two-Oscillator Circadian System of Tree Shrews (Tupaia belangeri) and Its Response to Light and Dark Pulses

Influence of different periods of exposure to hot environment on rumen function and diet digestibility in sheep

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