The response of dorsal horn neurons to graded intensities of colorectal distention 4-7 h after subcutaneous injection of vehicle (n = 12 for Abrupt and n = 11 for Sustained) or DPN (3 mg/kg, n = 22 for Abrupt and n = 14 for Sustained), and after spinal application of DPN (n = 5 for Abrupt and n = 6 for Sustained). A, Abrupt neurons. B, Sustained neurons. * p < 0.05, *** p < 0.001 compared with the vehicle group. # p < 0.05, ## p < 0.01, ### p < 0.001 compared with the vehicle group for same pressure.