No evidence for extraocular light induced phase shifting of human melatonin, cortisol and thyrotropin rhythms

Lindblom, Niki; Heiskala, Hannu; Hätönen, Taina; Mustanoja, Satu; Alfthan, Henrik; Alila-Johansson, Aino; Laakso, Minna

doi:10.1097/00001756-200003200-00012

Cited by 27 publications

(10 citation statements)

References 11 publications

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“…All but two of the subjects (86%) exhibited an increase in REM sleep. This finding is in contrast to several recent studies that have failed to demonstrate an effect of extraocular light administration on other central nervous system activities (10,14,18,25,27,53).…”

Section: Discussioncontrasting

confidence: 99%

Enhancement of REM sleep during extraocular light exposure in humans

Murphy

Campbell

2001

American Journal of Physiology-Regulatory, Integrative and Comp

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This study examined the effects on sleep of light administered to an extraocular site. A 3-h photic stimulus was applied to the popliteal region during sleep in 14 human subjects. Each subject also underwent a control stimulus condition during a separate laboratory session. The proportion of rapid eye movement (REM) sleep during the 3-h light administration session increased by an average of 31% relative to the control condition. The frequency but not the duration of REM episodes was altered during light exposure, thereby shortening the REM/non-REM (NREM) cycle length. No other sleep stages were significantly affected during light administration nor was sleep architecture altered after the light-exposure interval. These results confirm that extraocular light is transduced into a signal that is received and processed by the human central nervous system. In addition, they expand to a novel sensory modality previous findings that REM sleep can be enhanced by sensory stimulation.

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Section: Discussioncontrasting

confidence: 99%

Enhancement of REM sleep during extraocular light exposure in humans

Murphy

Campbell

2001

American Journal of Physiology-Regulatory, Integrative and Comp

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“…The most recent of these was by researchers from Cornell University, who suggested that bright light applied to the area behind the human knee would shift circadian rhythms of body temperature and melatonin (Campbell and Murphy 1998). But like earlier reports, these studies have not withstood independent verification (Koorengevel et al 2001;Lindblom et al 2000aLindblom et al , 2000bLockley et al 1998), suggesting that the original observations resulted from some unrecognised artefact of the experimental procedures (Foster 1998;Yamazaki et al 1999).…”

Section: Light Circadian Rhythms and Novel Ocular Photoreceptorsmentioning

confidence: 96%

Opsins and mammalian photoentrainment

Bellingham

Foster

2002

Cell Tissue Res

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Research over the past decade has provided overwhelming evidence that photoreception in the vertebrate eye is not confined to the rod and cone photoreceptors. It appears that photoreceptor cells within the inner retina provide irradiance information to a wide variety of different photosensory tasks including photoentrainment, pupillary constriction and masking behaviour. Action spectra in mice lacking all rod and cone photoreceptors ( rd/rd cl) have demonstrated the existence of a previously uncharacterised, opsin/vitamin-A-based photopigment with peak sensitivity at 479 nm (opsin photopigment/OP(479)). The review addresses the question: has the gene encoding OP(479) already been isolated, and if not, what type of gene should we be seeking and where in the eye might this gene be expressed? On the basis of available data, the gene that encodes OP(479) remains unidentified, and two broad possibilities exist. On the assumption that OP(479) will be like all of the other vertebrate photopigments (ocular and extraocular) and share a close phylogenetic relationship based upon amino acid identity and a conserved genomic structure, then the gene encoding OP(479) has yet to be isolated. Alternatively, there may have been a separate line of photopigment evolution in the vertebrates that has given rise to the melanopsin family. If true then the mammalian melanopsin gene may encode OP(479). Only when melanopsin and other candidates for OP(479) have been functionally expressed, and shown to encode a photopigment that matches the action spectrum of OP(479), can firm conclusions about the identity of the non-rod, non-cone ocular photoreceptor of mammals be made.

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“…Nonetheless, some scientists challenged the findings at the time for pragmatic reasons; namely, that eye loss in humans blocks photoentrainment [ 188 ]. Other groups attempted to replicate these findings using various approaches [ 189 , 190 , 191 ] and then the methodologies were replicated precisely [ 192 ]. All failed to show that light applied to the popliteal region would phase shift the circadian system.…”

Section: The Effects Of Light On the Human Circadian Systemmentioning

confidence: 99%

Circadian Photoentrainment in Mice and Humans

Foster

Hughes

Peirson

2020

Biology

109

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Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review the mechanisms and responses of the mouse and human circadian systems to light. Both utilize a network of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). In both species action spectra and functional expression of OPN4 in vitro show that melanopsin has a λmax close to 480 nm. Anatomical findings demonstrate that there are multiple pRGC sub-types, with some evidence in mice, but little in humans, regarding their roles in regulating physiology and behavior. Studies in mice, non-human primates and humans, show that rods and cones project to and can modulate the light responses of pRGCs. Such an integration of signals enables the rods to detect dim light, the cones to detect higher light intensities and the integration of intermittent light exposure, whilst melanopsin measures bright light over extended periods of time. Although photoreceptor mechanisms are similar, sensitivity thresholds differ markedly between mice and humans. Mice can entrain to light at approximately 1 lux for a few minutes, whilst humans require light at high irradiance (>100’s lux) and of a long duration (>30 min). The basis for this difference remains unclear. As our retinal light exposure is highly dynamic, and because photoreceptor interactions are complex and difficult to model, attempts to develop evidence-based lighting to enhance human circadian entrainment are very challenging. A way forward will be to define human circadian responses to artificial and natural light in the “real world” where light intensity, duration, spectral quality, time of day, light history and age can each be assessed.

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No evidence for extraocular light induced phase shifting of human melatonin, cortisol and thyrotropin rhythms

Cited by 27 publications

References 11 publications

Enhancement of REM sleep during extraocular light exposure in humans

Enhancement of REM sleep during extraocular light exposure in humans

Opsins and mammalian photoentrainment

Circadian Photoentrainment in Mice and Humans

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