Peptidergic innervation in infantile hypertrophic pyloric stenosis.

The gastrointestinal tract harbors several populations of peptide containing nerve fibers. Among the gut neuropeptides are vasoactive intestinal peptide (VIP), substance P, enkephalin, and gastrin releasing peptide (GRP). We have examined specimens from five patients with pyloric stenosis and from five controls immunocytochemically with respect to the density of nerve fibers containing VIP, substance P, enkephalin, or GRP. In the control specimens VIP and enkephalin fibers were fairly numerous, whereas substance P and GRP fibers were few. In the pyloric stenosis patients the density of VIP fibers and enkephalin fibers was reduced in the smooth muscle. In the myenteric ganglia there was no such reduction. Substance P and GRP fibers were rare as in controls. The results indicate a reduction of VIP and enkephalin fibers in smooth muscle in pyloric stenosis patients and may be interpreted to support the view that an impaired neuronal function is involved in the pathophysiology of pyloric stenosis.