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 interstiti al cells (ICs), yet these cells are important in electrical rhythmicit y and neurotransmission in the gastrointestinal tract, This study char acterized the development of ICs and the onset of electrical rhythmici ty in the murine intestine, Methods: Antibodies against c-Kit (e.g., t he receptor for stern cell factor) were used to label ICs of the small intestines of embryos and neonatal mice. Labels for enteric neuroblas ts and smooth muscle cells were used to study neighboring cells, Devel opment was examined also with electron microscopy and electrophysiolog ical techniques, Results: c-Kit-like Immunoreactivity (c-Kit-LI) was d etected in gastrointestinal tissues at embryonic day 12.5. Labeled cel ls 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 lo ngitudinal muscle cells and ICs of Phe 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 aft er 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 longit udinal muscle cells, Development of IC-MY correlates with the initiati on of electrical rhythmicity.