Sleep spindles: pharmacological effects in humans.

In the present paper we summarize the effects of a variety of drugs on sleep spindle activity in humans. The data are derived from 16 studies conducted in our laboratories during the past several years. The Sleep Analyzing Hybrid Computer was utilized to score each record for sleep stage and spindle activity. To the best of our knowledge, this collection of data is the largest currently available on the relationship between drug administration and standardized sleep spindle parameters in normal human subjects. Ten of the studies are dose-response evaluations. We consider this design a powerful and useful approach for basic sleep pharmacology research. Marked spindle enhancement was produced by flurazepam. WE-941 (a new benzodiazepine hypnotic), methaqualone, and secobarbital. Smaller differences were found for atropine, scopolamine, and caffeine. The results are discussed with respect to drug-class differences, sleep induction properties, the current literature, and the benzodiazepine hypothesis. Some of our future research plans with respect to spindle pharmacology also are presented.