Myenteric neurons of the mouse small intestine undergo significant electrophysiological and morphological changes during postnatal development

Key points  Different functional types of neurons within the gut wall form circuits that regulate intestinal motility. To examine the postnatal development of electrical properties of different classes of enteric neurons, we performed intracellular recordings from neurons in the mouse duodenum at three ages: postnatal day (P)0, P10–11 and adult. Like adults, two main morphological classes of neurons are present at P0 and P10–11. P0 and P10–11 neurons with Dogiel type II (DII) morphology had multiple long processes that achieved their adult projection length by P10–11. However, they differed electrophysiologically from adult DII neurons in that they displayed prominent afterdepolarizing potentials. Most electrical properties of neurons with a single long process were mature by P10–11. However, these neurons showed significant postnatal changes in morphology and projection length. Major morphological and electrophysiological changes in enteric neurons occur postnatally, which could underlie changes in gut motility during development.