Myenteric and submucosal plexuses of the congenital aganglionosis rat (spotting lethal) as revealed by scanning electron microscopy.

A rat with a congenital aganglionosis develops a mega-small intestine and megacolon. This rat mutant has been used as an animal model for Hirschsprung's disease. The myenteric and submucosal plexuses of the rats were exposed by the trypsin-HCl digestion method and examined by scanning electron microscopy. In the control rats the myenteric and submucosal plexuses were present throughout the gut. However, in the mutant rats the myenteric plexus of duodenum was different from those of control rats; the mesh of plexuses varied both in size and shape. There were no myenteric or submucosal plexuses in the distal ileum or colon.