Adrenergic Innervation of Bowel in Hirschsprung's Disease

Some observations on the intrinsic nervous mechanism in Hirschsprung's disease

“…Since it is known that adrenoceptors are located both on ganglia and on nerve endings, adrenergic modulation could also operate in the absence of ganglia by means of a direct action on the nerve fibres. In this connexion it is interesting to note that Bennett et al (1968) and Gannon et al (1969) have observed that more adrenergic fibres are present in the aganglionic segment than in the normal bowel. Therefore, since both the sympathetic modulating mechanism and the sites on which it could impinge are present, any failure of adrenergic modulation should be ascribed only to a functional defect for which there is no evidence at the morphological level.…”

“…Most recent investigations have been carried out on the distribution of adrenergic nerves in the smooth muscle layers and on the qualitative and quantitative modifications of cholinergic bundles of nerve fibres (Smith, 1967;Bennett, Garrett, and Howard, 1968;Gannon, Noblet, and Burnstock, 1969;Howard and Garrett, 1970a;Weinberg, 1970). Since the earliest histochemical observations on Hirschsprung's disease it has been recognized that the most striking feature in the aganglionic segment is the increase in number and size of intramural cholinergic fibres (Bodian, Carter, and Ward, 1951;Niemi, Kouvalainen, and Hjelt, 1961;Howard and Nixon, 1968;Garrett and Howard, 1969;Howard and Garrett, 1970b).…”

Influence of Ischemia on Noradrenergic Nerves in the Terminal Colon of Humans and Rats

“…In histochemical studies on sympathetic innervation o f the aganglionic gut from patients with Hirschsprung's disease, some investigators found a dense in nervation o f noradrenergic nerves in the aganglionic segments [6,8,15], while others demonstrated a small number o f fluorescent noradrenergic nerves in the segments [3,7]. These variant findings on the noradrenergic innervation in bowels o f Hirschsprung's dis ease may be explained as follows.…”

“…A concomitant ab normal innervation of the enteric nervous system was revealed by silver impregnation method [12]. The sympathetic nerves have been investigated in the aganglionic bowel, using fluorescence histochemistry [3,6,7,8,15], However, the localization o f noradrener gic nerves in the diseased bowel remains con troversial. In our examinations o f 13 children with Hirschsprung's disease.…”

Characteristics of cholinergic neuroeffector transmission of ganglionic and aganglionic colon in Hirschsprung's disease.

“…If such a mechanism were in operation, this should result in a relaxation of spastic gut, but this is not the case in Hirschsprung's disease. The possibility exists that since sympathetic innervation of the aganglionic part of the bowel is very rich, even more adrenergic fibres8 28 and noradrenaline content929 are located there than in the normal bowel. The lack of inhibitory a2 adrenoceptors on cholinergic neurons cannot be attributed to the functional deficiency of the noradrenergic inhibition on cholinergic hyperactivity, since exogenous noradrenaline was able to reduce acetylcholine release via a2 adrenoceptor stimulation.…”