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

Figure 4 Effects of in vitro treatment with granisetron on rat colon contractile response to electrical field stimulation and to acetylcholine. A: Incubation with granisetron (G) (3 μmol/L, 15 min) did not significantly modify the electrical field stimulation (EFS)-induced contractile response compared to vehicle. ANOVA results: F_treatments = 1.26, df = 1/9, P = 0.29; F_frequencies = 22.50, df = 2/18, P = 0.001; F_{treatments x frequencies} = 1.79, df = 2/18, P = 0.21; B: Incubation with G (3 μmol/L, 15 min) did not affect the contractile response to acetylcholine (ACh) (0.1-100 μmol/L) compared to vehicle. ANOVA results: F_treatments = 3.48, df = 1/9, P = 0.09; F_{concentrations} = 21.35, df = 3/27, P < 0.0001; F_{treatments x concentrations} = 0.08, df = 3/27, P = 0.85. Values are expressed as the mean ± SD of 6-8 experiments.