COMPARATIVE EFFECTS OF RESERPINE ON THE SLEEP CYCLE OF MAN AND CAT

¹ Michigan Neuropsychopharmacology Research Program, Department of Pharmacology, University of Michigan, Ann Arbor, Michigan

Previously published studies of the effects of reserpine on rapid eye movement (REM) sleep in man and cat reported divergent results. These discrepancies indicated a need to determine the effect of single doses of reserpine on both the cat and the human sleep cycle. Human volunteers were studied for seven consecutive nights, and cats were studied for six consecutive 24-hour periods. The dose scale utilized was 0.01, 0.04 and 0.14 to 0.16 mg/kg of reserpine i.m. for both the humans and the cats. Reserpine depressed slow-wave or non-rapid eye movement sleep in both man and cat. In the cat, the duration of this dose-related effect was 24 to 36 hours; in man the effect was seen on the night of reserpine administration as well as the two or three subsequent nights. REM sleep was greatly depressed for 48 hours in the cat, and no rebound phenomena were seen. However, in man, although REM sleep was sharply decreased on the night of reserpine administration, there was a large dose-related increase on subsequent nights (35-66% of total sleep time on the second night after reserpine), which exceeded the deficit incurred on the night of reserpine administration. The prolonged effect of large doses of reserpine on slow-wave sleep and initial depression of REM sleep in cat and man and yet the marked difference between cat and man of subsequent effects on REM sleep indicate important species similarities as well as differences that must be considered in the pharmacology of sleep.