Involvement of the serotonergic system in orexin-induced behavioral alterations in rats

• DOI: 10.1016/s0167-0115(01)00355-x
• Publication Date: 2002-10-11T19:12:08Z
• Authors: Ichiyo Matsuzaki; Takeshi Sakurai; Kaiko Kunii; Toshiaki Nakamura; Masashi Yanagisawa; Katsutoshi Goto
• Keywords: Ritanserin; Metergoline

We have demonstrated involvement of the serotonergic system in orexin-induced behavioral responses in rats. Orexin-A and -B (hypocretin-1 and -2) significantly increased total locomotor activity when administered centrally. They also induced behavioral alterations; increasing grooming, face washing and wet dog shaking in rats. Haloperidol inhibited orexin-induced hyperlocomotion and these behavioral alterations. Serotonin antagonists, ritanserin and metergoline, did not attenuate orexin-induced hyperlocomotion but partly inhibited orexin-induced behavioral alterations. These results suggest that the dopaminergic system might be involved in orexin-induced hyperlocomotion, while both the serotonergic system as well as the dopaminergic system might be involved in orexin-induced behavioral responses.