Fig. 2. Bar chart illustrating the antinociceptive effects of intrathecal coadministration of a single ineffective dose of gabapentin (300 μg) with various low doses of morphine ( white bar ). Measures examined included cage crossing, rearing, and hind limb extension activities in rats with acute pancreatitis (n = 5 per dose) or for morphine alone (n = 6 per dose). Values are represented as the mean ± SEM for the initial 10 min of activity in a novel cage experience. Surgical baseline behaviors were tested for each of the animals in the drug studies for comparison to its own behavior after a single treatment (total n = 20 for the combined morphine plus gabapentin groups and total n = 24 for the morphine alone doses). The 0-μg dose (hatched bar) represents the aCSF vehicle treated control group in animals with intrathecal and intraductal catheters after bradykinin infusion (n = 6) used as controls combined for both studies. The dotted line illustrates the values for gabapentin alone (300 μg) from fig. 1A,(9.5 ± 1.45 for crossing, 7.0 ± 1.79 for rearing, and 6.33 ± 1.94 for hind limb extension). Black bars indicate treatment with morphine alone (same data as in fig. 1B ) for comparisons. Comparisons were made between surgical baseline and drug groups using the Wilcoxon test ( # P < 0.05). Comparisons were made to the combined gabapentin and morphine treatment groups using Mann–Whitney U-tests versus the 0 μg aCSF vehicle treated control group (* P < 0.05; ** P < 0. 01); versus morphine alone (+ P < 0.05; ++ P < 0.01); and versus gabapentin alone (ˆ P < 0.05; ˆˆ P < 0.01). MS = morphine sulfate; GBP = gabapentin.