[Genetic basis of autonomic gastrointestinal motility and pathophysiological models]

The origin of rhythmicity in gastrointestinal motility was long thought to involve the activity of interstitial cells of Cajal (ICC) that locate in close association with enteric neurons and smooth muscle cells. We have demonstrated that significant decrease in the number of cells immunopositive to c-Kit, a type of tyrosine kinase receptor, in the gastrointestinal tract of mice mutated at the W/c-kit locus and BALB/c mice administered with neutralizing c-Kit antibody leads to the impaired autonomic motility of the gastrointestinal tract. It is also demonstrated that ICC express c-kit which plays important roles in development and maintenance of the ICC network in the gastrointestinal tract. ICC, derived from mesenchymal cells, are classified into smooth muscle type and fibroblast type by their morphology and tissue location. The ligand for c-Kit, Sl factor (SLF), has shown to be expressed in enteric neurons and gastrointestinal smooth muscle cells. Studies with mutant mice and transgenic mice have suggested that functional c-Kit/SLF is required for the differentiation and proliferation of ICC as pacemakers and mediators of neural regulation in gastrointestinal motility. Here we review the genetic basis of autonomic gastrointestinal motility and the pathophysiological models.