Gena Glickman | University of California, San Diego (original) (raw)
Papers by Gena Glickman
Chronobiology International, 2012
The daily pattern of blood-borne melatonin varies seasonally under the control of a multi-oscilla... more The daily pattern of blood-borne melatonin varies seasonally under the control of a multi-oscillator circadian pacemaker. Here we examine patterns of melatonin secretion and locomotor activity in Siberian and Syrian hamsters entrained to bimodal LDLD8:4:8:4 and LD20:4 lighting schedules that facilitate novel temporal arrangements of component circadian oscillators. Under LDLD, both species robustly bifurcated wheel-running activity in distinct day scotophase (DS) and night scotophase (NS) bouts. Siberian hamsters displayed significant melatonin increases during each scotophase in LDLD, and in the single daily scotophase of LD20:4. The bimodal melatonin secretion pattern persisted in acutely extended 16 h scotophases. Syrian hamsters, in contrast, showed no significant increases in plasma melatonin during either scotophase of LDLD8:4:8:4 or in LD20:4. In this species, detectable levels were observed only when the DS of LDLD was acutely extended to yield 16 h of darkness. Established species differences in the phase lag of nocturnal melatonin secretion relative to activity onset may underlie the above contrast: In non-bifurcated entrainment to 24 h LD cycles, Siberian hamsters show increased melatonin secretion within ≈ 2 h after activity onset, whereas in Syrian hamsters, detectable melatonin secretion phase lags activity onset and the L/D transition by at least 4 h. The present results provide new evidence indicating multi-oscillator regulation of the waveform of melatonin secretion, specifically, the circadian control of the onset, offset and duration of nocturnal secretion.
Journal of Clinical …, 2001
The aim of this study was to test if the three cone photopic visual system is the primary ocular ... more The aim of this study was to test if the three cone photopic visual system is the primary ocular photoreceptor input for human circadian regulation by determining the effects of different wavelengths on light-induced melatonin suppression. Healthy subjects with stable sleeping patterns (wake-up time 7: 30 AM i 12 min) and normal color vision were exposed at night to full-���eld 505 nm or 555 nm monochromatic stimuli or darkness for 90 min. Plasma collected before and after exposures was quantified for melatonin. Subjects ...
Lux, 2003
R��sum��/Abstract La lumi��re que re��oit l'oeil active un chemin du syst��me nerveux qui r�... more R��sum��/Abstract La lumi��re que re��oit l'oeil active un chemin du syst��me nerveux qui r��gule la physiologie du syst��me circadien et neuroendocrinien. Ce chemin est s��par�� de mani��re pr��dominante de celui de la vision et des diff��rents r��flexes visuels. Une rupture des syst��mes circadiens et neuroendocriniens, qui peut r��sulter de changements saisonniers, journaliers ou rapides �� l'exposition habituelle �� la lumi��re peut contribuer �� g��n��rer divers troubles, cliniques ou non. Il est d��sormais bien ��tabli que l'exposition �� ...
PUBLICATIONS-COMMISSION INTERNATIONALE DE L ECLAIRAGE CIE, 2003
Journal of Clinical Endocrinology and Metabolism, Jan 1, 2001
The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion c... more The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion cell photoreceptor in the mammalian eye containing the photopigment melanopsin. Nine action spectrum studies using rodents, monkeys, and humans for these responses indicate peak sensitivities in the blue region of the visible spectrum ranging from 459 to 484 nm, with some disagreement in short-wavelength sensitivity of the spectrum. The aim of this work was to quantify the sensitivity of human volunteers to monochromatic 420-nm light for plasma melatonin suppression. Adult female (n = 14) and male (n = 12) subjects participated in 2 studies, each employing a within-subjects design. In a fluence-response study, subjects (n = 8) were tested with 8 light irradiances at 420 nm ranging over a 4-log unit photon density range of 10 10 to 10 14 photons/cm 2 /sec and 1 dark exposure control night. In the other study, subjects (n = 18) completed an experiment comparing melatonin suppression with equal photon doses (1.21 × 10 13 photons/cm 2 /sec) of 420 nm and 460 nm monochromatic light and a dark exposure control night. The first study demonstrated a clear fluence-response relationship between 420-nm light and melatonin suppression (p < 0.001) with a half-saturation constant of 2.74 × 10 11 photons/cm 2 /sec. The second study showed that 460-nm light is significantly stronger than 420-nm light for suppressing melatonin (p < 0.04). Together, the results clarify the visible short-wavelength sensitivity of the human melatonin suppression action spectrum. This basic physiological finding may be useful for optimizing lighting for therapeutic and other applications.
Journal of Biological Rhythms, 2008
The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion c... more The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion cell photoreceptor in the mammalian eye containing the photopigment, melanopsin.
Abstract The present invention involves a light system for stimulating or regulating neuroendocri... more Abstract The present invention involves a light system for stimulating or regulating neuroendocrine, circadian, and photoneural systems in mammals based upon the discovery of peak sensitivity ranging from 425-505 nm; a light meter system for quantifying light which stimulates or regulates mammalian circadian, photoneural, and neuroendocrine systems.
The present invention involves a light system for stimulating or regulating neuroendocrine, circa... more The present invention involves a light system for stimulating or regulating neuroendocrine, circadian, and photoneural systems in mammals based upon the discovery of peak sensitivity ranging from 425-505 nm; a light meter system for quantifying light which stimulates or regulates mammalian circadian, photoneural, and neuroendocrine systems.
ABSTRACT The aim of this study was to test if the three cone photopic visual system is the primar... more ABSTRACT The aim of this study was to test if the three cone photopic visual system is the primary ocular photoreceptor input for human circadian regulation by determining the effects of different wavelengths on light-induced melatonin suppression. Healthy subjects with stable sleeping patterns (wake-up time 7: 30 AM+ 12 min) and normal color vision were exposed at night to full-field 505 nm or 555 nm monochromatic stimuli or darkness for 90 min. Plasma collected before and after exposures was quantified for melatonin.
Risk factors for the health and safety of astronauts and NASA ground control workers include dist... more Risk factors for the health and safety of astronauts and NASA ground control workers include disturbed circadian rhythms and altered sleep-wake patterns. These physiological changes can result in decrements in alertness, concentration, performance, and in turn, can threaten the safety of personnel and the objectives of space missions. In studies of astronauts and NASA ground control workers, light treatment has been used as an effective countermeasure to provide entrainment of circadian rhythms and sleep-wake patterns.
Journal of …, Jan 1, 2001
Journal of Clinical …, Jan 1, 2001
Biological …, Jan 1, 2006
Chronobiology International, 2012
The daily pattern of blood-borne melatonin varies seasonally under the control of a multi-oscilla... more The daily pattern of blood-borne melatonin varies seasonally under the control of a multi-oscillator circadian pacemaker. Here we examine patterns of melatonin secretion and locomotor activity in Siberian and Syrian hamsters entrained to bimodal LDLD8:4:8:4 and LD20:4 lighting schedules that facilitate novel temporal arrangements of component circadian oscillators. Under LDLD, both species robustly bifurcated wheel-running activity in distinct day scotophase (DS) and night scotophase (NS) bouts. Siberian hamsters displayed significant melatonin increases during each scotophase in LDLD, and in the single daily scotophase of LD20:4. The bimodal melatonin secretion pattern persisted in acutely extended 16 h scotophases. Syrian hamsters, in contrast, showed no significant increases in plasma melatonin during either scotophase of LDLD8:4:8:4 or in LD20:4. In this species, detectable levels were observed only when the DS of LDLD was acutely extended to yield 16 h of darkness. Established species differences in the phase lag of nocturnal melatonin secretion relative to activity onset may underlie the above contrast: In non-bifurcated entrainment to 24 h LD cycles, Siberian hamsters show increased melatonin secretion within ≈ 2 h after activity onset, whereas in Syrian hamsters, detectable melatonin secretion phase lags activity onset and the L/D transition by at least 4 h. The present results provide new evidence indicating multi-oscillator regulation of the waveform of melatonin secretion, specifically, the circadian control of the onset, offset and duration of nocturnal secretion.
Journal of Clinical …, 2001
The aim of this study was to test if the three cone photopic visual system is the primary ocular ... more The aim of this study was to test if the three cone photopic visual system is the primary ocular photoreceptor input for human circadian regulation by determining the effects of different wavelengths on light-induced melatonin suppression. Healthy subjects with stable sleeping patterns (wake-up time 7: 30 AM i 12 min) and normal color vision were exposed at night to full-���eld 505 nm or 555 nm monochromatic stimuli or darkness for 90 min. Plasma collected before and after exposures was quantified for melatonin. Subjects ...
Lux, 2003
R��sum��/Abstract La lumi��re que re��oit l'oeil active un chemin du syst��me nerveux qui r�... more R��sum��/Abstract La lumi��re que re��oit l'oeil active un chemin du syst��me nerveux qui r��gule la physiologie du syst��me circadien et neuroendocrinien. Ce chemin est s��par�� de mani��re pr��dominante de celui de la vision et des diff��rents r��flexes visuels. Une rupture des syst��mes circadiens et neuroendocriniens, qui peut r��sulter de changements saisonniers, journaliers ou rapides �� l'exposition habituelle �� la lumi��re peut contribuer �� g��n��rer divers troubles, cliniques ou non. Il est d��sormais bien ��tabli que l'exposition �� ...
PUBLICATIONS-COMMISSION INTERNATIONALE DE L ECLAIRAGE CIE, 2003
Journal of Clinical Endocrinology and Metabolism, Jan 1, 2001
The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion c... more The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion cell photoreceptor in the mammalian eye containing the photopigment melanopsin. Nine action spectrum studies using rodents, monkeys, and humans for these responses indicate peak sensitivities in the blue region of the visible spectrum ranging from 459 to 484 nm, with some disagreement in short-wavelength sensitivity of the spectrum. The aim of this work was to quantify the sensitivity of human volunteers to monochromatic 420-nm light for plasma melatonin suppression. Adult female (n = 14) and male (n = 12) subjects participated in 2 studies, each employing a within-subjects design. In a fluence-response study, subjects (n = 8) were tested with 8 light irradiances at 420 nm ranging over a 4-log unit photon density range of 10 10 to 10 14 photons/cm 2 /sec and 1 dark exposure control night. In the other study, subjects (n = 18) completed an experiment comparing melatonin suppression with equal photon doses (1.21 × 10 13 photons/cm 2 /sec) of 420 nm and 460 nm monochromatic light and a dark exposure control night. The first study demonstrated a clear fluence-response relationship between 420-nm light and melatonin suppression (p < 0.001) with a half-saturation constant of 2.74 × 10 11 photons/cm 2 /sec. The second study showed that 460-nm light is significantly stronger than 420-nm light for suppressing melatonin (p < 0.04). Together, the results clarify the visible short-wavelength sensitivity of the human melatonin suppression action spectrum. This basic physiological finding may be useful for optimizing lighting for therapeutic and other applications.
Journal of Biological Rhythms, 2008
The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion c... more The circadian and neurobehavioral effects of light are primarily mediated by a retinal ganglion cell photoreceptor in the mammalian eye containing the photopigment, melanopsin.
Abstract The present invention involves a light system for stimulating or regulating neuroendocri... more Abstract The present invention involves a light system for stimulating or regulating neuroendocrine, circadian, and photoneural systems in mammals based upon the discovery of peak sensitivity ranging from 425-505 nm; a light meter system for quantifying light which stimulates or regulates mammalian circadian, photoneural, and neuroendocrine systems.
The present invention involves a light system for stimulating or regulating neuroendocrine, circa... more The present invention involves a light system for stimulating or regulating neuroendocrine, circadian, and photoneural systems in mammals based upon the discovery of peak sensitivity ranging from 425-505 nm; a light meter system for quantifying light which stimulates or regulates mammalian circadian, photoneural, and neuroendocrine systems.
ABSTRACT The aim of this study was to test if the three cone photopic visual system is the primar... more ABSTRACT The aim of this study was to test if the three cone photopic visual system is the primary ocular photoreceptor input for human circadian regulation by determining the effects of different wavelengths on light-induced melatonin suppression. Healthy subjects with stable sleeping patterns (wake-up time 7: 30 AM+ 12 min) and normal color vision were exposed at night to full-field 505 nm or 555 nm monochromatic stimuli or darkness for 90 min. Plasma collected before and after exposures was quantified for melatonin.
Risk factors for the health and safety of astronauts and NASA ground control workers include dist... more Risk factors for the health and safety of astronauts and NASA ground control workers include disturbed circadian rhythms and altered sleep-wake patterns. These physiological changes can result in decrements in alertness, concentration, performance, and in turn, can threaten the safety of personnel and the objectives of space missions. In studies of astronauts and NASA ground control workers, light treatment has been used as an effective countermeasure to provide entrainment of circadian rhythms and sleep-wake patterns.
Journal of …, Jan 1, 2001
Journal of Clinical …, Jan 1, 2001
Biological …, Jan 1, 2006