The D 1 dopamine receptor antagonist SCH 23390 enhances REM sleep in the rat

Abstract

The effect of the D 1 dopamine receptor antagonist SCH 23390 on sleep patterns was studied in rats by means of the electroencephalographic (EEG) technique. Haloperidol, an established D 2 antagonist neuroleptic, was used for comparison. Over a very small dose range (0.003–0.03 mg/kg, subcutaneously), SCH 23390 significantly increased the time spent in total sleep, including rapid eye movement (REM) and non-REM sleep. The magnitude of the overall change of REM sleep was considerably greater than that of non-REM sleep. Enhancement of the amount of REM was characterized by increase in number of episodes but no change of latency to the first period of REM. Haloperidol increased non-REM sleep at 0.3–3 mg/kg, orally, but did not affect other measures of REM. Considering the small dose range at which SCH 23390 was effective, and the fact that REM and non-REM sleep may be unrelated events, it is suggested that promotion of REM sleep is a specific effect induced by selective blockade of D 1 receptors.