Quinacrine can be used for fluorescence microscopy to visualize certain cell bodies and fibres in the myenteric plexus of the intestine, forming a network different from the cholinergic and adrenergic systems. In the Piebald mouse, animal model of congenital megacolon, the quinacrine positive plexus is thin in the distal narrowed segment and well developed in the large proximal zone. In Hirschsprung's disease, the quniacrine positive network has the same pathologic features but, contrary to the animal model, there is an increased number and size of extrinsic cholinergic and adrenergic fibres. So this mouse is an animal model of a pseudo-Hirschsprung's disease, which has not yet been reported in human pathology.