Physiology & behavior
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Physiology & behavior · May 1995
Locomotor activity and melatonin rhythms in rats under non-24-h lighting cycles.
The adjustment of pineal melatonin and locomotor activity rhythms to 10:10-h light:dark (LD) or 14:14-h LD cycles was studied in male Wistar rats. Both lighting conditions were thought to be outside the limits of entrainment of the rest-activity rhythm in this species. We assumed that the rhythm of pineal melatonin synthesis might be more adaptable. ⋯ This melatonin pattern fitted the LD-adjusted activity rhythm. Thus, the melatonin rhythm did not adapt better than the activity rhythm to the exotic LD cycles. Instead, parallel changes were found.