Injection of orexin-A (100 pmol) into the VTA reduced emergence time [from 949 (118) to 727 (101) s; P=0.0058] and reduced the electroencephalographic burst-suppression ratio (BSR) (26.6 [10.2]% vs 44.3 [6.8]%; P=0.0027) during isoflurane anaesthesia.
Adult and aged Sprague-Dawley rats were used to assess the time to emergence after 30 min isoflurane anaesthesia (1.4 vol%), and differences in the orexinergic systems, including the number of orexinergic neurones, plasma orexin concentrations, and expression of orexin-1 (OX1R) and orexin-2 receptors, compared using immunofluorescence, radioimmunoassay, western blot, and real-time polymerase chain reaction.