Relationship between functional and histologic appearances of developing ganglion cells in the guinea pig rectum

Time dated fetal guinea-pigs between 47 and 67 days gestation were studied for segmental propulsive activity in the rectosigmoid under fluoroscopy. Large bowel from the sacrificed fetus was studied histologically to determine distribution and morphology of ganglion cells. Contractions were first observed on day 54 and these became more frequent and vigorous after day 63. Between 47-53 days gestation circular muscle is thin and neurons consists of cluster of neuroblastic cells. Near the end of gestation the neurons arrange themselves into discrete groups and have an appearance like mature ganglion cells.