Ileal distention relaxes the canine colon: A model of megacolon?

Guido Basilisco, Sidney F. Phillips

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Background/Aims: Reflex relaxation is a mechanism whereby the colon can show short-term dilatation in the absence of mechanical obstruction. This study investigated the tonic response of the canine colon to ileal distention and its pharmacological control. Methods: In four dogs, the tone of the proximal colon was recorded by a barostat during distention of the terminal ileum. Results: Ileal distention inhibited ileal motility and relaxed the colon. Adrenergic blockade by propranolol plus phentolamine, nicotinic blockade by hexamethonium, and the nitric oxide synthase inhibitor Ngw-nitro-l-arginine methylester significantly increased resting tone of the colon but did not inhibit relaxation induced by ileal distention. Muscarinic blockade by atropine completely relaxed the colon, and no further decrease in tone was observed after ileal distention. The neurokinin 2 antagonist SR48968 did not alter colonic tone. Conclusions: The barostat was able to monitor resting tone of the canine colon, which was shown to be under inhibitory control by adrenergic, cholinergic-nicotinic, and nitric oxide-like transmitters. Inhibition of colonic tone by ileal distention was not mediated solely by adrenergic, cholinergic-nicotinic, or nitric oxide mechanisms. Reflex relaxation, possibly predisposing to acute colonic dilatation, may be activated by multiple mechanisms that may differ from those controlling resting tone.

Original languageEnglish
Pages (from-to)606-614
Number of pages9
JournalGastroenterology
Volume106
Issue number3
Publication statusPublished - 1994

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Megacolon
Canidae
Colon
Adrenergic Agents
Cholinergic Agents
Reflex
Dilatation
Nitric Oxide
Hexamethonium
Phentolamine
Atropine
Ileum
Propranolol
Nitric Oxide Synthase
Arginine
Pharmacology
Dogs

ASJC Scopus subject areas

  • Gastroenterology

Cite this

Ileal distention relaxes the canine colon : A model of megacolon? / Basilisco, Guido; Phillips, Sidney F.

In: Gastroenterology, Vol. 106, No. 3, 1994, p. 606-614.

Research output: Contribution to journalArticle

Basilisco, Guido ; Phillips, Sidney F. / Ileal distention relaxes the canine colon : A model of megacolon?. In: Gastroenterology. 1994 ; Vol. 106, No. 3. pp. 606-614.
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