Rebuttal from Nick J. Spencer, Tiong Cheng Sia, Simon J Brookes, Marcello Costa and Damien J. Keating

We absolutely agree that 5‐HT has multiple roles and that gut‐derived 5‐HT is an important hormone. However, this CrossTalk is about whether 5‐HT is necessary for the colonic motor patterns usually called ‘peristalsis’.

Drs Smith and Gershon's rebuttal states that we ‘highlight common misunderstandings about peristaltic reflexes’. CMMCs are commonly studied in mice, where they occur spontaneously. Peristalsis is often studied using propulsion of pellets in guinea pig colon. Both CMMCs and peristalsis persist after the removal of the mucosa. Thus, it is hard to argue that anything produced or released from mucosal cells, including serotonin from enterochromaffin cells, is necessary for CMMCs or peristalsis.