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Nonphotic entrainment of the human circadian pacemaker.

Klerman, EB, Rimmer, DW, Dijk, DJ, Kronauer, RE, Rizzo, JF and Czeisler, CA (1998) Nonphotic entrainment of the human circadian pacemaker. Am J Physiol, 274 (4 Pt 2). R991-R996.

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In organisms as diverse as single-celled algae and humans, light is the primary stimulus mediating entrainment of the circadian biological clock. Reports that some totally blind individuals appear entrained to the 24-h day have suggested that nonphotic stimuli may also be effective circadian synchronizers in humans, although the nonphotic stimuli are probably comparatively weak synchronizers, because the circadian rhythms of many totally blind individuals "free run" even when they maintain a 24-h activity-rest schedule. To investigate entrainment by nonphotic synchronizers, we studied the endogenous circadian melatonin and core body temperature rhythms of 15 totally blind subjects who lacked conscious light perception and exhibited no suppression of plasma melatonin in response to ocular bright-light exposure. Nine of these fifteen blind individuals were able to maintain synchronization to the 24-h day, albeit often at an atypical phase angle of entrainment. Nonphotic stimuli also synchronized the endogenous circadian rhythms of a totally blind individual to a non-24-h schedule while living in constant near darkness. We conclude that nonphotic stimuli can entrain the human circadian pacemaker in some individuals lacking ocular circadian photoreception.

Item Type: Article
Divisions : Surrey research (other units)
Authors :
Klerman, EB
Rimmer, DW
Kronauer, RE
Rizzo, JF
Czeisler, CA
Date : April 1998
Uncontrolled Keywords : NASA Discipline Regulatory Physiology, Non-NASA Center, Adult, Aged, Blindness, Body Temperature, Circadian Rhythm, Female, Humans, Male, Melatonin, Middle Aged, Photic Stimulation
Related URLs :
Depositing User : Symplectic Elements
Date Deposited : 17 May 2017 09:10
Last Modified : 24 Jan 2020 16:13

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