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

Figure 6 Effects of in vitro treatment with CORM-3 on rat colon contractile response to electrical field stimulation, without and with atropine, and to acetylcholine. A: Incubation with CORM-3 (C) (400 μmol/L) significantly increased the electrical field stimulation (EFS)-induced contractile response compared to vehicle at 10 Hz. ANOVA results: F_treatments = 2.75, df = 3/20, P = 0.07; F_frequencies = 55.38, df = 2/40, P < 0.0001; F_{treatments x frequencies} = 4.36, df = 6/40, P = 0.002. At 10 Hz: C (400 μmol/L) vs vehicle ^aP = 0.01; B: Co-incubation of C (100-400 μmol/L) with atropine (Atr) (3 μmol/L, 20 min) abolished the effect of C when administered alone. ANOVA results: F_treatments = 3.06, df = 3/20, P = 0.052; F_frequencies = 50.05, df = 2/40, P < 0.0001; F_{treatmentss x frequencies} = 1.14, df = 6/40, P = 0.36; C: Incubation with C (400 μmol/L) increased the contractile response to acetylcholine (ACh) (100 μmol/L) compared to vehicle. ANOVA results: F_treatments = 2.28, df = 3/22, P = 0.11; F_{concentrations} = 86.22, df = 3/66, P < 0.0001; F_{treatments x concentrations} = 3.49, df = 9/66, P = 0.02. For ACh 100 μmol/L: C (400 μmol/L) vs vehicle: ^bP = 0.012. Values are expressed as the mean ± SD of 6-8 experiments.