Figure 7.

Aganglionosis of the colon of miRet⁵¹/miRet⁵¹ animals. Whole-mount acetylcholinesterase histochemistry of neonatal duodenum (a,c,e,g) and colon (b,d,f,h) of +/+ (a,b), miRet⁹/miRet⁹ (c,d), miRet⁵¹/miRet⁵¹ (e,f) and Ret.k−/Ret.k− (−/−; g,h) neonates. In miRet⁵¹ homozygotes, although an apparently normal myenteric plexus forms in the small intestine, no enteric ganglia were present in the colon. RET-deficient animals fail to develop the myenteric plexus throughout the length of the intestine. (Top) Diagrammatic representation of the various gut segments. st, Stomach; si, small intestine; ce, cecum; li, large intestine. +/+, n = 37; 9/9, n = 18; 51/51, n = 23; −/−, n = 3.