Fig. 4.
A: subthreshold dose of 17 mg/kg (TNBS17) marginally suppressed the contractile response of colonic circular muscle strips to ACh on day 7 of inflammation. However, during the blockade of VPAC1/2 receptors by systemic infusion of their antagonist by an osmotic pump, as described in the legend of Fig. 5, the same dose of TNBS increased the suppression of reactivity to ACh. B: subthreshold dose of TNBS had no significant effect on the expression of the α1C subunit of Cav1.2 channels. However, during the blockade of VPAC1/2 receptors, as described above, the subthreshold dose significantly suppressed the expression of α1C subunit on day 7 of inflammation. C and D: subthreshold dose of TNBS had no significant effect on the nuclear abundance of p65 (C) or p50 (D). However, during the blockade of VPAC1/2 receptors, as described above, the same subthreshold dose significantly increased the nuclear translocation of NF-κB p65 and p50 subunits (C) and (D), respectively, in colonic muscularis externa. Rats treated with saline served as controls. N = 3 to 5 rats in each group. Blots are representative of 3 to 5 independent experiments. *P < 0.05 vs. control.