Effect of phentolamine on wakefulness and sleep during recovery from REM sleep deprivation in cats.

Adult cats with permanent EEG, EMG, EOG, and PGO electrodes were recorded for 24 hours started at the end of a 72-hour REMS deprivation induced by a platform-water-tank procedure and after receiving IP injections of phentolamine (20 mg/kg) or saline. Exposure of the cats to the platform-REMS deprivation procedure increased the percentage of REMS during the subsequent 24 hours. Phentolamine interacted with the platform REMS deprivation causing the peak of REMS percentage to occur during recovery hours 5-12. These findings indicate that blockade of alpha-receptors has an additive effect on platform-REMS deprivation induced REMS rebound in cats.