8-OH-DPAT is a potent and selective 5-HT agonist, with a pIC
50
of 8.19 for 5-HT1A; weakly binds to 5-HT1B (pIC
50
, 5.42), 5-HT (pIC
50
<5). 8-OH-DPAT has high affinity at 5-HT7 with a K
i
of 466 nM, and does not bind to 5-HT6 or 5-HT4.
8-OH-DPAT (1 mg/kg) normalizes hypolocomotion, significantly increases wakefulness and reduces the duration of REM sleep without effect on the duration of non-REM sleep in the dark period in orexin knockout (KO) mice. 8-OH-DPAT shows no obvious effect on wakefulness or the duration of either REM sleep or non-REM sleep in WT mice. 8-OH-DPAT (1 mg/kg, s.c.) activates 5-HT1A receptor in orexin knockout mice.