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[Adrenergic receptors in the pathogenesis of congenital megacolon (author's transl)]
Abstract:
Contractions of fresh specimens of taenial musculature from human colon were investigated under the influence of depolarization (bathing in solutions high in potassium), of acetylcholine, and of adrenaline; definite changes of contractile tension could be induced by these agents. The investigations were carried out using normal musculature as well as specimens from patients with congenital megacolon taken from the narrow segment. Contractions after depolarization and after cholinergic stimulation were equal in all specimens investigated, pre-extension of these specimens not differing significantly. Relaxation of colon musculature mediated by adrenergic receptors was very pronounced in normal musculature, but was lacking in specimens taken from the narrow segments of congenital megacolon. Sympathetic stimulation of normal taenial musculature does abolish completely cholinergically induced contractions. On the other hand, a preparation relaxed by adrenaline contracts very little after additional application of acetylcholine. These findings do suggest a severe disturbance of adrenergic receptors in the colon, or of adrenergic neuromuscular transmission in congenital megacolon.
Insights
Congenital megacolon disrupts colon muscle function, specifically impairing adrenergic receptor responses. This study reveals a significant lack of relaxation in affected colon tissue, suggesting a neuromuscular transmission disorder.
Area of Science:
- Gastroenterology
- Neurogastroenterology
- Pharmacology
Context:
- Investigated taenial musculature from human colon, including normal specimens and those from patients with congenital megacolon (narrow segment).
- Assessed contractile responses to depolarization (high potassium), acetylcholine (cholinergic agonist), and adrenaline (adrenergic agonist).
Purpose:
- To elucidate the functional changes in colon taenial smooth muscle in congenital megacolon.
- To determine the role of adrenergic receptors and neuromuscular transmission in the pathophysiology of congenital megacolon.
Summary:
- Depolarization and cholinergic stimulation induced comparable contractions in normal and congenital megacolon specimens.
- Normal colon musculature exhibited pronounced relaxation mediated by adrenergic receptors, which was absent in congenital megacolon specimens.
- Sympathetic stimulation abolished cholinergic contractions in normal muscle; however, adrenaline-pretreated muscle showed reduced acetylcholine-induced contractions, indicating impaired adrenergic function.
Impact:
- Findings suggest a severe disturbance of adrenergic receptors or neuromuscular transmission in the colon of patients with congenital megacolon.
- Highlights potential therapeutic targets for managing motility disorders in congenital megacolon.