Selective knockout of intramuscular interstitial cells reveals their role in the generation of slow waves in mouse stomach

1. Intracellular recording techniques were used to compare the patterns of electric al activity generated in the antral region of the stomachs of wild -type and W/W-V mutant mice. Immunohistochemical techniques were used to de termine the distribution of c-kit-positive interstitial cells of Cajal (ICC ) within the same region of the stomach. 2. In wild-type mice interstitial cells were found at the level of the myen teric plexus (ICCMY) and distributed within the smooth muscle bundles (ICCI M). In these preparations slow waves, which consisted of initial and second ary components, were detected. 3. In W/W-V mutant mice ICCMY could be identified at the level of the myent eric plexus but ICCIM were not detected within smooth muscle bundles. Intra cellular recordings revealed that smooth muscle cells generated waves of de polarization; these lacked a secondary component. 4. These results indicate that the secondary regenerative component of a sl ow wave is generated by ICCIM. Thus the depolarization arising from the pac emaker cells, ICCMY, is augmented by ICCIM, so causing a substantial membra ne depolarization in the circular muscle layer. Rather than contributing di rectly to rhythmical electrical activity, smooth muscle cells appear to dep olarize at the command of the two subpopulations of ICC.