In vitro study of spontaneous motility and cholinergic responses in the human Hirschsprung's disease colon

We conclude that the circular muscle of aganglionic colonic segments retains the ability to establish a Ca²⁺-dependent and atropine-insensitive spontaneous motility similar to the circular muscle of ganglionic tissue. However, both tissue segments differed considerably in response to external cholinergic stimulation with significantly enhanced phasic-to-tonic contraction ratios in aganglionic specimens. These findings will help understand the persistent circular muscle contraction in aganglionic bowel which is still a major challenge in the preoperative HD management.