Journal of Neuroscience, Vol 14, 6769-6778, Copyright © 1994 by Society for Neuroscience
Effects of prolonged sleep deprivation on local rates of cerebral energy metabolism in freely moving rats
CA Everson, CB Smith and L Sokoloff
Clinical Psychobiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892.
Although sleep deprivation interferes with biological processes essential
for performance, health, and longevity, previous studies have failed to
reveal any structural or functional changes in brain. We have therefore
measured local rates of cerebral glucose utilization (ICMRglc) with the
quantitative autoradiographic 2-14C-deoxyglucose method in an effort to
determine if and, if so, where sleep deprivation might affect function in
sleep-deprived rats. Sleep deprivation was maintained for 11-12 d, long
enough to increase whole body energy metabolism, thus confirming that
pathophysiological processes that might involve brain functions were
evolving. Deep brain temperature was also measured in similarly treated
rats and found to be mildly elevated relative to core body temperature.
Despite the increased deep brain temperature, systemic hypermetabolism, and
sympathetic activation, ICMRglc was not elevated in any of the 60 brain
structures examined. Average glucose utilization in the brain as a whole
was unchanged in the sleep-deprived rats, but regional decreases were
found. The most marked decreases in ICMRglc were in regions of the
hypothalamus, thalamus, and limbic system. Mesencephalic and pontine
regions were relatively unaffected except for the central gray area. The
medulla was entirely normal. The effects of sleep deprivation on brain
tended, therefore, to be unidirectional toward decreased energy metabolism,
primarily in regions associated with mechanisms of thermoregulation,
endocrine regulation, and sleep. Correspondence was found between the
hypometabolic brain regions and some aspects of peripheral symptoms.