The influence of ipsapirone, a 5-HT1A agonist, on sleep patterns of healthy subjects

Ipsapirone is a new pyrimidinylpiperazine ligand specific for 5-HT1A receptors, with potential therapeutic use in affective disorders. Because 5-HT is involved in the regulation of sleep, we investigated the effect of ipsapirone hydrochloride on sleep patterns in 18 normal, healthy subjects of both sexes. Compared to placebo, ipsapirone 5 mg administered by mouth three times daily for 14 days decreased rapid eye movement (REM) sleep duration and, by the tenth day of treatment, began to reduce slow wave sleep (SWS) duration. The decrease in REM sleep occurred in the first 3 h of sleep. The latency to REM sleep was increased from the first night following ipsapirone administration, remained increased throughout the 14 days of administration, and fell to equal latency on placebo immediately administration ended. Subjective assessments of sleep revealed no differences between ipsapirone and placebo. Our experiments confirm a role of 5-HT1A receptors in sleep. The effects of ipsapirone on the sleep patterns of patients with affective disorders still need to be determined.