METHODS: We examined the interactions between OXergic neurons and benzodiazepine receptors in orexin-A (100 nM) and K_ (25 mM)-evoked norepinephrine release from rat cerebrocortical slices.
      RESULTS: Midazolam, diazepam, and flunitrazepam concentration-dependently inhibited both OX-A- and K_-evoked norepinephrine release. The IC50 of midazolam for orexin-A-evoked release (0.87 _M, P _ 0.01), which was insensitive to flumazenil, was significantly lower than that of diazepam an flunitrazepam (around 60 _M), whereas the IC50s for K_-evoked release were not different among the benzodiazepines.
       CONCLUSION: There may be no interaction between OXergic neurons and central benzodiazepine receptors.