Effect of oleamide on sleep and its relationship to blood pressure, body temperature, and locomotor activity in rats

Oleamide (cis-9,10-octadecenoamide) is a brain lipid that has recently been isolated from the cerebral fluid of sleep-deprived cats. Intracerebroventr icular and intraperitoneal administration of oleamide induces sleep in rats . However, it is unclear whether oleamide's hypnogenic effects are mediated , in part, by its actions on blood pressure and core body temperature. Here we show that systemic administration of oleamide (10 and 20 mg/kg) in rats increased slow-wave sleep 2, without affecting blood pressure and heart ra te. In addition, oleamide decreased body temperature and locomotor activity in a dose-dependent manner. These latter effects were not correlated in ti me with the observed increases in slow-wave sleep. These data suggest that the hypnogenic effects of oleamide are not related to changes in blood pres sure, heart rate, or body temperature. (C) 2001 Academic Press.