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Light-Emitting Diodes (LED) for Primary Animal Habitat Lighting in Highly Controlled EnvironmentsSignificant alterations in Biological Clock responses have been reported following sidereal time changes (e.g., Jet-lag), and exposure to microgravity (e.g., daytime sleepiness). Additionally, light reduces circulating melatonin (spectral specificity greatest between 450-500 nm). It was hypothesized that LEDs can replace the current light sources used in zero gravity and terrestrial research laboratories because of their small size, low mass, low energy consumption and long functional life. This report evaluates the capacity of LEDs to entrain the circadian system of rats as judged by measurement of overt behavioral circadian rhythms (activity, feeding, drinking). These data were collected in highly controlled environments similar to the shuttle Animal Enclosure Modules. Two groups were compared: control - animals exposed to standard cool-white fluorescent lights, and test - animals exposed to LEDs with a spectral power distribution matching the fluorescent lights. Gross locomotor activity, feeding and drinking frequencies were continuously monitored and stored at 10 minute intervals. Animals were exposed to the following photoperiods: 28 days of 12L:12D, 19 days of 24L:0D and 16 days of 12L:12D. Light intensities tested varied between 0.1 to 100 lux. Rats received food and water ad libitum, and temperature and humidity were controlled throughout the study. The general health status of all rats was acceptable for each day of this study. No incidents of aggressive behavior were observed. Growth, locomotor activity, food and water consumption were comparable for all groups of animals, i.e, the circadian characteristics of the animals under these conditions were comparable. These results indicate that LED arrays are as effective in maintaining circadian rhythm stability as the commonly used cool-white fluorescent light sources. LEDs with their flexible spectrum, low energy requirements and minimal heat production have advantages for some chronopharmacology studies and for microgravity animal habitats.
Document ID
20020038811
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Winget, C. M.
Syrkin, N.
Heeke, D.
Mele, G.
Holley, D. C.
Dalton, Bonnie P.
Date Acquired
August 20, 2013
Publication Date
January 1, 1996
Subject Category
Life Sciences (General)
Meeting Information
Meeting: 7th International Conference on Chronopharmacology and Chronotherapeutics
Location: Heidelberg
Country: Germany
Start Date: September 10, 1996
End Date: September 14, 1996
Funding Number(s)
PROJECT: RTOP 106-50-06-40
CONTRACT_GRANT: NCC2-779
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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