Exposure to the cannabinoid agonist WIN 55, 212-2 in adolescent rats causes sleep alterations that persist until adulthood

Abstract

Cannabis and, to a lesser extent, synthetic cannabinoids are used during adolescence, a period in which multiple brain areas are still undergoing development. Among such areas is the hypothalamus, which is implicated in the control of sleep-wake cycle. In the present report, we show that exposing adolescent rats to the cannabinoid receptor agonist WIN 55, 212-2 (0.1, 0.3 or 1.0 mg/kg, i.p) for 14 days during adolescence (i.e., from post-natal day 30-44) resulted in significant sleep disturbances when the animals became adult (post-natal day 80). These included decreased wakefulness and enhanced rapid eye movement sleep. Furthermore, we found that labeling for NeuN, a marker of postmitotic neurons, was significantly increased the dorsomedial hypothalamic nucleus of rats treated with WIN 55, 212-2. The results suggest that excessive cannabinoid receptor activation during adolescence can persistently influence sleep patterns and neuronal activity later in life.

Keywords: Adolescence; Cannabinoids; Rapid eye movement sleep; Sleep; WIN 55,212–2.