Korean J Neurogastroenterol Motil.  2004 Jun;10(1):63-71.

The Action of Substance P on the Colonic Motility in Rat Colon

• Choi JH
• Nah BK
• Bae SS
• Choi KW
• Chae HB
• Park SM
• Youn SJ

Abstract

BACKGROUND/AIMS
The mechanism by which substance P (SP) stimulates colonic motility has not yet been fully elucidated. The study objective was to investigate the action mechanism of SP on isolated rat colon.
METHODS
An isolated, vascular rat colon was perfused with Krebs' solution via the superior mesenteric artery. After a basal period, SP was administered at concentrations of 10 to 200 pM, and the intraluminal pressures were monitored. After pre-infusion of atropine, tetrodotoxin, propranolol, phentolamine and hexamethonium, SP was infused and the pressures were monitored. The motility changes were expressed as percentage changes of motility index over basal period.
RESULTS
SP increased the colonic motility at concentrations of 10 pM, 50 pM, 100 pM and 200 pM at the proximal colon (32.0+/-8.3%, 78.1+/-22.4%, 107.7+/-35.5% and 63.9+/-25.8%, respectively), and at the distal colon (52.0+/-12.3%, 170.1+/-64.0%, 273.0+/-47.4% and 277.3+/-49.6%, respectively). In the proximal colon, the stimulating effect of SP was inhibited by atropine, tetrodotoxin and propranolol, and, in the distal colon, by atropine and tetrodotoxin.
CONCLUSIONS
SP stimulates rat colonic motility, and the stimulating effect is more potent at the distal colon. The action of SP, being mediated via cholinergic and adrenergic input and at the proximal colon, is mediated mainly by cholinergic input at the distal colon.

Keyword

Substance P; Colonic motility; Cholinergic input; Adrenergic input

MeSH Terms

Animals
Atropine
Colon*
Hexamethonium
Mesenteric Artery, Superior
Phentolamine
Propranolol
Rats*
Substance P*
Tetrodotoxin
Atropine
Hexamethonium
Phentolamine
Propranolol
Substance P
Tetrodotoxin