Suggestive evidence for a direct innervation of mucosal mast cells.

Mast cells are often observed near nerves and functional evidence suggests an innervation of these cells. In the present ultrastructural study, nerve terminals containing many small clear vesicles and a few large vesicles with dense matrix were observed in direct contact with the plasma membrane of mucosal mast cells in the rat ileum, strongly suggestive of a direct innervation.