Phase response curve to 1 h light pulses for the European rabbit (<i>Oryctolagus cuniculus</i>)

Kennedy, Gerard; Hudson, Robyn

doi:10.1080/07420528.2016.1191506

Cited by 6 publications

(13 citation statements)

References 34 publications

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“…We tested 17 females, where possible in five LD cycles with long light and short dark periods within (22:2, 23:2) and close to or outside the rabbit's range of circadian entrainment (18:2, 20:2, 27:2) (Kennedy & Hudson, 2016). We used short, 2 h dark periods as we thought this might constrain nursing to a narrower time period and make it easier to discern any separation of the nursing rhythm from the general circadian system, e.g.…”

Section: Methodsmentioning

confidence: 99%

“…If the daily pattern of nursing in the rabbit is controlled by the circadian system it could be expected to entrain more readily to LD cycles close to 24 h (Daan & Pittendrigh, 1976;Kennedy & Hudson, 2016;Pittendrigh & Daan, 1976a, b, c;review in Jilge & Hudson, 2001).…”

Section: Experiments 1: Influence Of Ld Cycles On the Nursing Patternmentioning

confidence: 99%

“…We therefore conducted two experiments designed to address the question whether the daily pattern of nursing by the rabbit corresponds to an hourglass-type model or is indeed better considered part of this species' endogenous circadian system. In Experiment 1 we examined the relation between females' circadian-regulated daily feeding rhythm and their pattern of daily nursing visits with free access to their young under a range of LD cycles within and outside the rabbit's known range of LD entrainment (Kennedy & Hudson, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Regulation of the rabbit’s once-daily pattern of nursing: a circadian or hourglass-dependent process?

Apel

Hudson

Coleman

et al. 2020

Chronobiology International

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The European rabbit Oryctolagus cuniculus has an unusual pattern of nursing behaviour.After giving birth in a nursery burrow (or laboratory nest box), the mother immediately leaves the young and only returns to nurse for a few minutes once approximately every 24 hours. It has been assumed this schedule, like a variety of other functions in the rabbit, is under circadian control. This assumption has been largely based on findings from mothers only permitted restricted access to their young once every 24 hours. However, in nature and in the laboratory, mothers with free access to young show nursing visits with a periodicity shorter than 24 hours, that does not correspond to other behavioural and physiological rhythms entrained to the prevailing 24-hour light/dark (LD) cycle. To investigate how this unusual, apparently non-circadian pattern might be regulated we conducted two experiments using female Dutch belted rabbits housed individually in cages designed to automatically register feeding activity and nest box visits. In Experiment 1 we recorded the behaviour of 17 mothers with free access to their young under five different LD cycles with long photo and short scotoperiods, spanning the limits of entrainment of the rabbit's circadian system.Whereas feeding rhythms were entrained by LD cycles within the rabbit's circadian range of entrainment, nursing visits showed a consistently shorter periodicity regardless of the LD regimen, largely independent of the circadian system. In Experiment 2 we tested a further 12 mothers under more conventional LD 16:8 cycles but "trained" by having access to the nest box restricted to one hour at the same time each day for the first seven days of nursing.Mothers were then allowed free access either when their young were left in the box (n = 6), or when the litter had been permanently removed (n = 6). Mothers with pups still present returned to nurse them on the following days according to a similarly advancing pattern to the mothers of Experiment 1 despite the previous seven days of "training" to an experimentally enforced 24 hour nursing schedule as commonly used in previous studies of rabbit maternal 4 behaviour. Mothers whose pups had been removed entered the box repeatedly several times on the first day of unrestricted access, but on subsequent days did so only rarely, and at times of day apparently unrelated to the previously scheduled access. We conclude that the pattern of the rabbit's once-daily nursing visits has a periodicity largely independent of the circadian system, and that this is reset at each nursing. When nursing fails to occur nest box visits cease abruptly, with mothers making few or no subsequent visits. Together, these findings suggest that the rabbit's once-daily pattern of nursing is regulated by an hourglass-type process with a period less than 24 hours that is reset at each nursing, rather than by a circadian oscillator.Such a mechanism might be particularly adaptive for rhythms of short duration that should end abruptly with a sudden change in context su...

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Section: Methodsmentioning

confidence: 99%

Section: Experiments 1: Influence Of Ld Cycles On the Nursing Patternmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Regulation of the rabbit’s once-daily pattern of nursing: a circadian or hourglass-dependent process?

Apel

Hudson

Coleman

et al. 2020

Chronobiology International

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“…The time of year may also have a significant effect; in winter organisms will experience more traffic-related pulses due not only to a longer period of night-time, but also because these dark or twilight hours are more likely to the large number of studies that have used regular night-time light pulses (commonly of 30 min or 1 hr duration, but sometimes much less) to produce phase response curves to understand the circadian rhythms of a variety of organisms (e.g. Daan & Pittendrigh, 1976;Flari & Lazaridou-Dimitriadou, 1995;Ford & Cook, 1988;Gronfier, Wright, Kronauer, Jewett, & Czeisler, 2004;Kennedy & Hudson, 2016;Kumar & Singaravel, 2014). It also excludes phenomena such as the recovery times of night vision ("dark adaptation") after exposure to artificial lighting (and associated "bleaching" of photopigments), which may in insects and vertebrates take 30 min or more (Martin, 2017;Post & Goldsmith, 1965), with profound consequences for resource acquisition and predator avoidance.…”

Section: Developmentsmentioning

confidence: 99%

Nature, extent and ecological implications of night‐time light from road vehicles

Gaston

Holt

2018

Journal of Applied Ecology

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The erosion of night‐time by the introduction of artificial lighting constitutes a profound pressure on the natural environment. It has altered what had for millennia been reliable signals from natural light cycles used for regulating a host of biological processes, with impacts ranging from changes in gene expression to ecosystem processes.Studies of these impacts have focused almost exclusively on those resulting from stationary sources of light emissions, and particularly streetlights. However, mobile sources, especially road vehicle headlights, contribute substantial additional emissions.The ecological impacts of light emissions from vehicle headlights are likely to be especially high because these are (1) focused so as to light roadsides at higher intensities than commonly experienced from other sources, and well above activation thresholds for many biological processes; (2) projected largely in a horizontal plane and thus can carry over long distances; (3) introduced into much larger areas of the landscape than experience street lighting; (4) typically broad “white” spectrum, which substantially overlaps the action spectra of many biological processes and (5) often experienced at roadsides as series of pulses of light (produced by passage of vehicles), a dynamic known to have major biological impacts.The ecological impacts of road vehicle headlights will markedly increase with projected global growth in numbers of vehicles and the road network, increasing the local severity of emissions (because vehicle numbers are increasing faster than growth in the road network) and introducing emissions into areas from which they were previously absent. The effects will be further exacerbated by technological developments that are increasing the intensity of headlight emissions and the amounts of blue light in emission spectra. Synthesis and applications. Emissions from vehicle headlights need to be considered as a major, and growing, source of ecological impacts of artificial night‐time lighting. It will be a significant challenge to minimise these impacts whilst balancing drivers' needs at night and avoiding risk and discomfort for other road users. Nonetheless, there is potential to identify solutions to these conflicts, both through the design of headlights and that of roads.

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“…Under D:D locomotion in these animals free‐ran, with tau greater or smaller than 24 hr in each 50% of the population (Kennedy, Hudson, & Armstrong, ). A phase‐response curve to light for wheel running was constructed by administering 1 hr light pulses (1,000 lux) at different circadian times (separated by at least 14 days) to adult male and female rabbits kept under constant darkness (Kennedy & Hudson, ). Under these conditions the mean free‐running tau was 23.94 hr for females and 23.91 hr for males.…”

Section: Behavioral Neuroendocrinologymentioning

confidence: 99%

Behavioral, neuroendocrine and physiological indicators of the circadian biology of male and female rabbits

Aguilar‐Roblero

González‐Mariscal

2018

Eur J of Neuroscience

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Adult rabbits show robust circadian rhythms of: nursing, food and water intake, hard faeces excretion, locomotion, body temperature, blood and intraocular pressure, corticosteroid secretion, and sleep. Control of several circadian rhythms involves a light‐entrained circadian clock and a food‐entrained oscillator. Nursing periodicity, however, relies on a suckling stimulation threshold. Brain structures regulating this activity include the paraventricular nucleus and preoptic area, as determined by lesions and quantification of cFOS‐ and PER1 clock gene‐immunoreactive proteins. Melatonin synthesis in the rabbit pineal gland shows a diurnal rhythm, with highest values at night and lowest ones during the day. In kits the main zeitgeber is milk intake, which synchronizes locomotor activity, body temperature, and corticosterone secretion. Brain regions involved in these effects include the median preoptic nucleus and several olfactory structures. As models for particular human illnesses rabbits have been valuable for studying glaucoma and cardiovascular disease. Circadian variations in intraocular pressure (main risk factor for glaucoma) have been found, with highest values at night, which depend on sympathetic innervation. Rabbits fed a high fat diet develop cholesterol plaques and high blood pressure, as do humans, and such increased fat intake directly modulates cardiovascular homeostasis and circadian patterns, independently of white adipose tissue accumulation. Rabbits have also been useful to investigate the characteristics of sleep across the day and its modulation by infections, cytokines and other endogenous humoral factors. Rabbit circadian biology warrants deeper investigation of the role of the suprachiasmatic nucleus in regulating most behavioral and physiological rhythms described above.

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Phase response curve to 1 h light pulses for the European rabbit (Oryctolagus cuniculus)

Cited by 6 publications

References 34 publications

Regulation of the rabbit’s once-daily pattern of nursing: a circadian or hourglass-dependent process?

Regulation of the rabbit’s once-daily pattern of nursing: a circadian or hourglass-dependent process?

Nature, extent and ecological implications of night‐time light from road vehicles

Behavioral, neuroendocrine and physiological indicators of the circadian biology of male and female rabbits

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