Effects of pinealectomy on baseline sleep and response to sleep deprivation.
OBJECTIVE
We have previously reported that older (24 mo.) Fischer rats manifest a diminished post-sleep deprivation increase in NREM and REM sleep. In order to examine whether this decline reflects an age-related change in pineal function, we are now reporting on baseline and recovery sleep parameters in pinealectomized 3-, 12-, and 24-month old rats following 24 hours of sleep deprivation using the disk-over-water method.


METHODS
Three independent age groups; within each group there were sequential measures of sleep under baseline conditions and during recovery from sleep deprivation.


METHODS
The Sleep Research Laboratory at the University of Chicago


METHODS
56 male Fisher (F344) rats


METHODS
24 hours of total sleep deprivation using the disk-over-water method


METHODS
Sleep staging of EEG and EMG, and power spectral analysis of the EEG RESULTS: Pinealectomized (pinex) rats did not differ from sham-operated (sham) rats in total sleep, REM sleep, super-modal high-amplitude NREM sleep (HS2), a measure of NREM EEG delta power, or circadian rhythm amplitude. In the pinex rats, there was a modest (2.5%) age-independent increase in NREM sleep (p<0.02). The pinex rats of all ages failed to manifest the increase in NREM sleep during recovery seen in the sham-operated animals (p<0.04).


CONCLUSIONS
We found no evidence that altered pineal function is responsible for age-related changes in baseline sleep in the rat. These data also suggest that, independent of age, normal pineal function may be relevant to the ability to generate increased NREM sleep in response to prior sleep deprivation.
Mendelson
W B
WB
Sleep Research Laboratory, The University of Chicago, Illinois 60615, USA. wmendels@yoda.bsd.uchicago.edu
Bergmann
B M
BM
D000818:Animals; D004569:Electroencephalography; D008297:Male; D010870:Pineal Gland / Q000601:surgery*; D051381:Rats; D011916:Rats, Inbred F344; D012892:Sleep Deprivation / Q000503:physiopathology*; D012895:Sleep, REM / Q000502:physiology*