The change to the frequency of ICCs found in the experimental subgroup for the rectum among the newborn rats with anorectal anomalies was 8.19 cells/mm2, and the change to the frequency of ganglion cells was 13.35 cells/mm2. These findings were similar to those of Macedo et al.8, and lower than those of Alberti et al.18 in the colon of a population of normal rats, and this difference may have occurred because of the increase in the number of cells that takes place from the neonatal phase to adult age