Pain thresholds in rats during recovery from REM sleep deprivation.

Using 30 Sprague-Dawley female rats, threshold to pain was measured over the course of recovery from REM sleep deprivation. Relative to the untreated controls and to their own pretreatment thresholds, the REM-deprived animals showed significantly reduced pain thresholds which were still evident 96 hours after the termination of the REM deprivation. Possible implications of these data for research with analgesic drugs were noted.