Do we need to revise the role of interstitial cells of Cajal in gastrointestinal motility?

摘要

as its name suggests, the tunica muscularis of the gastrointestinal tract is dominated by smooth muscle cells, which perform all the mechanical work required for digestion, absorption, and waste removal. The muscle layers also contain several other cell types, which, despite representing a much smaller percentage of the total cellular content, also contribute to gastrointestinal motility by regulating smooth muscle contractions. In this group belong interstitial cells of Cajal (named after Santiago Ramon y Cajal and commonly referred to as ICC), which represent ~5% of cells within the muscular coat. ICC are mesenchymal cells that have been described throughout the gastrointestinal tract of all vertebrates studied to date (15). They can be distinguished from other cell types on the basis of their light microscopic and ultrastructural morphology (16), gene expression pattern, and surface markers (2). Until the discovery of Kit, a type III receptor tyrosine kinase, as a light microscopic marker for ICC (10), investigators could only speculate on the function of these cells on the basis of less specific histochemical staining techniques and electron microscopy and by relying on relatively crude approaches to separate them from the rest of the tissues for physiological analyses.