抄録
Using an embryoid body (EB) culture system, we have made a functional organ-like cluster, the "gut" from mouse embryonic stem (ES) cells (ES gut). Each ES gut has a hemispherical or cystic structure and exhibits spontaneous contractions. A dense distribution of interstitial cells of Cajal (ICC) was identified by c-Kit immunoreactivity, and specific subcellular structures of ICC and smooth muscle cells were identified. However, no ganglia of enteric neurons were found in the spontaneously differentiated ES-gut like organ structures. The aims of the present study were to differentiate enteric neural ganglia by adding some factors at an appropriate timing, and to characterize peristaltic-like movements in the gut-like organ with enteric neural ganglia and ICC. We finally succeeded in forming enteric neural ganglia. In the ES-gut like organ with enteric neural ganglia, focal stimulation caused a distinct propagated Ca2+ response that was abolished by tetrodotoxin. Hexamethonium or atropine also markedly attenuated the Ca2+ response. These results suggest that cholinergic excitatory enteric motor nerves mediated via nicotinic receptors elicit the increase of [Ca2+]i. Furthermore, we found highly coordinated peristaltic-like movements in gut-like organ with enteric neural ganglia and ICC. We conclude that both ICC and enteric neural ganglia are essential to generate complete peristaltic-like movements in ES-gut like organ. [Jpn J Physiol 55 Suppl:S24 (2005)]
