FUNCTIONAL INNERVATION OF THE AGANGLIONIC SEGMENT IN HIRSCHSPRUNGS-DISEASE - A COMPARISON OF THE SHORT-SEGMENT AND LONG-SEGMENT TYPE

The authors examined the neuro-effector transmission in the aganglioni c segment from 13 patients with Hirschsprung's disease, 10 patients ha d short-segment type and three patients had long-segment type. Circula r muscle strips were prepared and the responses to transmural electric al field stimulation were examined using the isometric tension recordi ng technique, In the ganglionic preparations from the short- and long- segment cases, the stimulation evoked a biphasic response consisting o f a relaxation and an atropine-sensitive contraction. The relaxation w as partly inhibited by N-omega-nitro-L-arginine (NNLA, a nitric oxide [NO] synthase inhibitor), and the effect of NNLA was abolished complet ely in the presence of L-arginine, which suggested the presence of NO- mediated inhibitory innervation. In the aganglionic preparations from the short-segment-type cases, stimulation evoked only an atropine-sens itive contraction, while in the aganglionic preparations from the long -segment-type cases, a weak inhibitory response persisted after the co ntractile response was abolished by atropine. This NO-mediated inhibit ory response was frequently detected as the examined region approached the ganglionic segment. These results suggest that the aganglionic se gment in the long-segment-type cases might therefore receive NO-mediat ed inhibitory input from the proximal ganglionic segment. Copyright (C ) 1997 by W.B. Saunders Company.