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Effects of aging on the diurnal pattern of water intake in rats
R D Burwell1, J Whealin, M Gallagher
1Department of Psychology, University of North Carolina, Chapel Hill 27599-3270.
Abstract:
This study was undertaken to confirm previous findings that Long-Evans rats exhibit age-related changes in the diurnal/nocturnal distribution of water intake and to examine the circadian pattern of these age-related changes. Twenty-one aged and 10 young pathogen-free rats were continuously monitored for water consumption over 12:12 h light/dark cycles. ANOVA, profile analysis, and cosinor analysis each demonstrated that aged rats differed from young rats. The age-related changes in circadian pattern can be described as a blunted rhythm (decreased amplitude) and an altered timing of peak activity (advanced acrophase). These differences, however, were only apparent in a subset of aged rats with the remaining aged rats exhibiting a circadian pattern indistinguishable from that of the young group.
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