HCRTR2 and insomnia: Scammell and Winrow (2011) demonstrated that OXR2 or non-competitive orexins inhibitors were effective in treating insomnia, suggesting that OXR2 may play a more important role. Irving observed an increase in the OXR1 gene expression in rats with cerebral ischemia (Irving et al., 2002), while OXR2 gene expression did not change significantly.