Fig. 7

Co-application of orexin-A plus naloxone more reduced GABAergic IPSCs in LC neurons of morphine-treated rats. a Statistical comparison of eIPSCs amplitude between naloxone alone, co-application of orexin-A plus naloxone, and co-application of SB-orexin-A-naloxone vs. orexin-A alone. b Statistical comparison of sIPSCs frequency between naloxone alone, co-application of orexin-A plus naloxone, and co-application of SB-orexin-A-naloxone vs. orexin-A alone. The application of orexin-A (100 nM) alone in the absence of naloxone had no significant effect on eIPSCs amplitude and sIPSCs frequency (one-sample t test). Naloxone alone significantly (P < 0.05) decreased eIPSCs amplitude (11.89 ± 4.57%) and sIPSCs frequency (16.76 ± 5.05%) compared with orexin-A. Co-application of orexin-A plus naloxone on eIPSCs amplitude (32.90 ± 5.26%) and sIPSCs frequency (42.40 ± 4.53%) vs. orexin-A alone had significant difference (P < 0.001). Co-application of SB-orexin-A-naloxone also significantly (P < 0.05) decreased eIPSCs amplitude (8.12 ± 1.39%) and sIPSCs frequency (12.13 ± 2.04%) compared with orexin-A alone. In addition, percentage of decrease in eIPSCs amplitude (21.01 ± 5.13%) and sIPSCs frequency (25.64 ± 5.58%) was significant (P < 0.05) between co-application orexin-A and naloxone vs. naloxone alone. Each bar represents the mean ± SEM (*) indicated statistical significance between orexin-A alone compared to naloxone alone and co-application of orexin-A and naloxone (P < 0.05, P < 0.001) and also (#) signified statistical significance for comparison between naloxone alone and co-application of orexin-A and naloxone (P < 0.05)