The influence of orexins on ethanol-induced behavioral sensitization in male mice

• Published in: Neuroscience letters Vol. 551; pp. 84 - 88
• Main Authors: Macedo, Giovana Camila, Kawakami, Suzi Emiko, Vignoli, Thiago, Sinigaglia-Coimbra, Rita, Suchecki, Deborah
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 13.09.2013
• Subjects: Animals; Behavioral sensitization; Ethanol; Ethanol - pharmacology; Fos; Hypothalamus - drug effects; Hypothalamus - metabolism; Immunohistochemistry; Intracellular Signaling Peptides and Proteins - metabolism; Male; Mice; Motor Activity - drug effects; Neurons - drug effects; Neurons - metabolism; Neuropeptides - metabolism; Orexin type 1 receptor; Orexins; Proto-Oncogene Proteins c-fos - metabolism; Immunohistochemistry; Fos; Ethanol; Behavioral sensitization; Orexin type 1 receptor
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2013.07.010

•Ethanol-induced behavioral sensitization activated orexin neurons in the LH.•Blockade of orexin 1 receptors prevented expression of behavioral sensitization.•Orexin system participates in ethanol-induced behavioral sensitization in mice. Recent evidence indicates the involvement of orexin in reward circuitry and drug addiction. In the present study we evaluated the role of orexin in ethanol-induced behavioral sensitization. In the first experiment, Swiss male mice received seven administrations of saline or ethanol (2.2g/kg, i.p., chronic), every other day. On the last day of treatment, half of saline-treated mice received a saline injection (saline) whereas the other half received 2.2g/kg of ethanol (i.p., acute). Behavioral sensitization was assessed by locomotor activity tests and after the last one, immunoreactivity for orexin and Fos (ORX+Fos-ir) was assessed in the lateral hypothalamic area. Chronic ethanol treatment produced behavioral sensitization and a trend for greater ORX+Fos-ir. In the second experiment, mice were treated as in Experiment 1 and type 1 orexin receptor antagonist, SB334867 (20mg/kg), was administered before the ethanol challenge successfully blocking the expression of sensitization in mice chronically treated with EtOH. These results indicate that orexin plays a role in ethanol-induced behavioral sensitization.