Abnormalities of nerve fibers in the circular muscle of patients with slowtransit constipation

Abnormalities of the enteric nervous system are thought to explain the path ophysiology of motility disorders. Our aim was to determine if particular c lasses of enteric neurons are affected in slow transit constipation (STC). Specimens were taken from the terminal ileum and ascending, transverse and descending colon of patients undergoing subtotal colectomy for STC. Immunoh istochemistry was performed using antisera to neuron-specific enolase, tach ykinin, leu-enkephalin, choline acetyltransferase, vasoactive intestinal pe ptide, nitric oxide synthase, tyrosine hydroxylase and neuropeptide Y. The density of nerve fibres labelled with these antibodies in each layer was co mpared with age-matched controls. The density of nerve fibres with tachykin in and enkephalin immunoreactivity was reduced in the colonic circular musc le of the 15 patients with STC, whereas innervation of all other layers was normal. This reduction of tachykinin-immunoreactive nerve fibres also occu rred in nine of the 12 specimens of terminal ileum examined. No difference was detected in the density or distribution of nerve fibres using the other antisera. Excitatory nerve fibres are present in the circular muscle in ST C but they are deficient in tachykinins and enkephalin.