Figure 2:

Effects of MNTX on morphine antinociception in a TNBS-induced model of inflammatory colitis. On Day 0, mice were implanted with 75 mg morphine pellets and administered a TNBS solution to induce colonic inflammation or vehicle. Separate groups of mice received once daily administration of 25 mg/kg MNTX (s.c.) or vehicle and were tested for daily nociceptive responses (s) in a warm-water tail-withdrawal (panel A) or hot plate assay (panel C). Significant between-group differences compared to the vehicle + vehicle condition at each day are denoted by filled symbols (p<0.05); graphical denotation of within-group differences are omitted for clarity but are included in text (section 3.2). After the baseline assessment on Day 3, mice with sub-maximal response latencies were challenged with 10 mg/kg morphine (s.c.) to determine if MNTX antagonism of morphine’s effects was surmountable (panels B and D). Significant within-subject differences in post-morphine response latencies compared to pre-morphine latencies are denoted by filled symbols, * p<0.05.