SLEEP-DEPRIVATION IN THE RAT .20. DIFFERENCES IN WAKE AND SLEEP TEMPERATURES DURING RECOVERY

We examined the relationship between wake and sleep peritoneal tempera ture (T-ip) during recovery from short-term (five rats, 5 days of depr ivation) and long-term (nine rats, 14-21 days) total sleep deprivation (TSD). Mammalian body temperature normally declines in the passage fr om wakefulness to sleep. Recovery from TSD featured reductions of the typical wake-sleep T-ip differences. Previous studies from our laborat ory have shown that chronic TSD in the rat produces a progressive rise in energy production and an initial rise in wake T-ip followed by a l ater fall in T-ip to below baseline that becomes more acute as death b ecomes imminent. During recovery from both short-term TSD (wherein pre -recovery wake T-ip was still above baseline) and long-term TSD (where in pre-recovery wake T-ip had fallen to below baseline), wake T-ip and energy production quickly returned towards baseline. On the first rec overy day, both short- and long-term TSD rats showed mean non-rapid ey e movement (NREM) and paradoxical sleep (PS) T-ip values that were sli ghtly, although not significantly, above mean wake T-ip. In shortterm TSD rats, wake-NREM and wake-PS T-ip differences were reduced from bas eline significantly (p < 0.0025) on the first recovery day and nonsign ificantly on the remaining three recovery days. In long-term TSD rats, wake-NREM and wake-PS T-ip differences were significantly (p < 0.001) reduced from baseline on the first four recovery day block. On the la st four recovery day block, wake-sleep T-ip differences tended to retu rn toward baseline. Hypothalamic wake-sleep temperature differences in long-term TSD rats showed similar reductions during recovery. The red uction of wake-sleep temperature differences in recovery does not supp ort either energy reduction or cooling functions for sleep.