Fig. 5

Pretreatment with the OX1R antagonist, SB-334867, prevented the effect of orexin-A on GABAergic IPSCs in the presence of naloxone in LC neurons of morphine-treated rats. a Sample traces of eIPSCs at a holding potential of − 70 mV during bath application of SB, orexin-A and naloxone, respectively, without washout. b Evoked IPSCs in the presence of SB and SB plus orexin-A were not significantly different in the absence of naloxone (baseline). SB-334867 (3 µM, SB) reversed the suppressive effect of orexin-A (100 nM) on eIPSC amplitude in the presence of naloxone (1 µM) (repeated measures ANOVA followed by Student–Newman–Keuls test, *P < 0.05, n = 8), while SB-334867 had no significant effect on evoked IPSCs in the absence of naloxone (baseline). c Sample traces of sIPSCs recorded during baseline and bath application of SB, orexin-A and naloxone, respectively, without washout. d Left, SB-334867 reversed the orexin-A effect on sIPSCs frequency in the presence of naloxone, but not during baseline (repeated measure ANOVA followed by Student–Newman–Keuls test, *P < 0.05, n = 8). Right, cumulative probability plots of sIPSCs inter-event interval compared to baseline and bath application of SB and SB-orexin-A-naloxone, respectively, without washout. e Left, sIPSCs amplitudes were not significantly different in the absence (baseline) and the presence of naloxone. Right, cumulative probability plots of sIPSCs amplitude during baseline and bath application of SB and SB-orexin-A-naloxone, respectively