Sleep deprivation of rats: the hyperphagic response is real

Author(s)

Koban‚ M. ; Sita‚ L.V. ; Le‚ W.W. ; Hoffman‚ G.E.

• Document type: Journal article
• Source: Sleep; v. 31, n. 7, p. 927, 2008.

Abstract

Study Objectives: Chronic sleep deprivation of rats causes hyperphagia without body weight gain. Sleep deprivation hyperphagia is prompted by changes in pathways governing food intake; hyperphagia may be adaptive to sleep deprivation hypermetabolism. A recent paper suggested that sleep deprivation might inhibit ability of rats to increase food intake and that hyperphagia may be an artifact of uncorrected chow spillage. To resolve this, a palatable liquid diet (Ensure) was used where spillage is insignificant. Design: Sleep deprivation of male Sprague Dawley rats was enforced for 10 days by the flowerpot/platform paradigm. Daily food intake and body weight were measured. On day 10, rats were transcardially perfused for analysis of hypothalamic mRNA expression of the orexigen, neuropeptide Y (NPY). Setting: Morgan State University, sleep deprivation and transcardial perfusion; University of Maryland, NPY in situ hybridization and analysis. Measurements and Results: Using a liquid diet for accurate daily measurements, there was no change in food intake in the first 5 days of sleep deprivation. Importantly, from days 6-10 it increased significantly, peaking at 29% above baseline. Control rats steadily gained weight but sleep-deprived rats did not. Hypothalamic NPY mRNA levels were positively correlated to stimulation of food intake and negatively correlated with changes in body weight. Conclusion: Sleep deprivation hyperphagia may not be apparent over the short term (i.e., <= 5 days), but when extended beyond 6 days, it is readily observed. The timing of changes in body weight and food intake suggests that the negative energy balance induced by sleep deprivation prompts the neural changes that evoke hyperphagia. (AU)

• FAPESP's process: 06/06289-9 - Training in the state-of-the-art immunocytochemistry and its combination with non-radioactive in situ hybridization: expression and activation of melanin concentrating hormone after unremitting REM sleep deprivation in rats
• Grantee: Luciane Valéria Sita
• Support Opportunities: Scholarships abroad - Research