Orexin-A facilitates emergence of the rat from isoflurane anesthesia via mediation of the basal forebrain

(A) Isoflurane depresses the c-Fos positive orexinegic neurons, while during emergence, the activities of orexinegic neurons were restored (the arrows in the right column indicate c-Fos and orexin double labeled neurons). (B) The concentration of plasma orexin-A and orexin-B decreased with isoflurane inhalation, while after termination of isoflurane and at emergence, just the orexin-A levels were restored. (C) Microinjection of orexin-A 30 or 100 pmol shortened the emergence time, while orexin-B did not influence the emergence time of isoflurane. (D) Microinjection of orexin receptor-1 antagonist SB 20 μg into basal forebrain delayed the emergence time, while orexin receptor-2 antagonist TCS had no effect.142