Carbon monoxide contributes to the constipating effects of granisetron in rat colon

Figure 3 Effect of in vivo administration of hemin alone and with granisetron on the time to first defecation. Hemin (50 μmol/L/kg) did not affect the time to first defecation. Co-administration of hemin (50 μmol/L/kg) with granisetron (G) (50, 75 μg/kg) resulted in an increased time to first defecation. Friedman’s test = 20.364 P = 0.000; post-hoc comparisons: hemin vs vehicle: P = 1; G 25 μg/kg + hemin vs vehicle: P = 0.108; G 50 μg/kg + hemin vs vehicle: ^aP = 0.028; G 75 μg/kg + hemin vs vehicle: ^bP = 0.004. Each point represents an individual observation.