STRUCTURAL STUDY ON THE APPEARANCE OF INNERVATION IN THE STOMACH OF MOUSE AND RAT EMBRYOS

The stomach of developing embryos was examined by light and electron m icroscopy on specimens taken at each embryonic day from 11 to 17 (rat) and from 10 to 16 (mouse). The aim of the study was to determine when the precursor cells of enteric neurons and endocrine cells colonize t he stomach and when they begin to express morphologic features of matu re cells. The findings show that the elements of the enteric nervous s ystem are recognizable and functionally mature prior to the appearance of morphologically detectable gut epithelial endocrine cells. Some as pects of neuronal differentiation in the wall of the stomach are also discussed.