Contribution of development to buspirone effects on REM sleep: a preliminary report

In order to assess whether development influences the regulation of rapid eye movement (REM) sleep by serotonergic (5-HT) systems, the REM sleep responses to the partial 5-HT(1A) agonist, buspirone, were assessed in 14 normal adolescent and adult volunteers. Subjects were studied on three separate sessions for three consecutive nights. On the second night of each session, subjects received placebo or one of two doses of buspirone (0.14 mg/kg and 0.28 mg/kg, orally). Night 3 was considered the "recovery" night. In adolescents, both doses of buspirone significantly delayed REM latency. In contrast, low-dose buspirone had no effect on REM latency in the adults, and there was only a tendency for prolongation of REM latency with the higher dose. Other measures of REM sleep on nights 2 and 3 were comparable between the two groups. These preliminary results suggest that post-synaptic 5-HT(1A) acceptor-coupled REM sleep responses, particularly REM latency, may be relatively greater in youngsters than in adults, possibly due to reduced presynaptic input. The findings are discussed in relation to the age-dependent expression of REM sleep changes associated with depression.