Development of c-Kit-positive cells and the onset of electrical rhythmicity in murine small intestine.

BACKGROUND & AIMS: Little is known about the development of interstitial cells (ICs), yet these cells are important in electrical rhythmicity and neurotransmission in the gastrointestinal tract. This study characterized the development of ICs and the onset of electrical rhythmicity in the murine intestine.
METHODS: Antibodies against c-Kit (e.g., the receptor for stem cell factor) were used to label ICs of the small intestines of embryos and neonatal mice. Labels for enteric neuroblasts and smooth muscle cells were used to study neighboring cells. Development was examined also with electron microscopy and electrophysiological techniques.
RESULTS: c-Kit-like immunoreactivity (c-Kit-LI) was detected in gastrointestinal tissues at embryonic day 12.5. Labeled cells were distributed along the outer perimeter of the intestine and had morphological features of neither smooth muscle cells nor ICs. Cells with c-Kit-LI were nonneural and seemed to be common precursors for longitudinal muscle cells and ICs of the myenteric plexus region (IC-MY). Longitudinal muscle cells lost c-Kit by E18, whereas IC-MY continued c-Kit expression into adulthood. Electrical rhythmicity developed after IC-MY, and longitudinal muscle cells became separate entities. ICs in the deep muscular plexus region developed after birth.
CONCLUSIONS: ICs have a nonneural origin. Common precursors yield IC-MY and longitudinal muscle cells. Development of IC-MY correlates with the initiation of electrical rhythmicity.