Korean J Gastroenterol.  2015 May;65(5):283-290. 10.4166/kjg.2015.65.5.283.

The Effect of Urocortin 1 on Motility in Isolated, Vascularly Perfused Rat Colon

• You IY
• Lee S
• Kim KB
• Lee HS
• Jang JS
• Yeon M
• Han JH
• Yoon SM
• Chae HB
• Park SM
• Youn SJ

• KMID: 2373224
• DOI: http://doi.org/10.4166/kjg.2015.65.5.283

Abstract

BACKGROUND/AIMS
Urocortin 1, a corticotropin-releasing factor related peptide, increases colonic motility under stressful conditions. We investigated the effect of urocortin 1 on colonic motility using an experimental model with isolated rat colon in which the blood flow and intestinal nerves were preserved. Furthermore, we assessed whether this effect was mediated by adrenergic or cholinergic nerves.
METHODS
Colonic motility was measured in the proximal and distal parts of resected rat colon. The colon resected from the peritoneum was stabilized, and then urocortin 1 (13.8, 138, 277, and 1,388 pM) was administered via a blood vessel. Motility index was measured in the last 5 min of the 15 min administration of urocortin 1 and expressed as percentage change from baseline. Subsequently, the change in motility was measured by perfusing urocortin 1 in colons pretreated with phentolamine, propranolol, hexamethonium, atropine, or tetrodotoxin.
RESULTS
At concentrations of 13.8, 138, 277, and 1,388 pM, urocortin 1 increased the motility of proximal colon (20.4+/-7.2%, 48.4+/-20.9%, 67.0+/-25.8%, and 64.2+/-20.9%, respectively) and the motility of distal colon (3.3+/-3.3%, 7.8+/-7.8%, 71.1+/-28.6%, and 87.4+/-32.5%, respectively). The motility induced by urocortin 1 was significantly decreased by atropine to 2.4+/-2.4% in proximal colon and 3.4+/-3.4% in distal colon (p<0.05). However, tetrodotoxin, propranolol, phentolamine, and hexamethonium did not inhibit motility.
CONCLUSIONS
Urocortin 1 increased colonic motility and it is considered that this effect was directly mediated by local muscarinic cholinergic receptors.

Keyword

Urocortins; Corticotropin-releasing factor; Rats; Cholinergic receptors; Muscarinic receptors

MeSH Terms

Animals
Colon/*drug effects/physiology
Injections, Intravenous
Male
Muscle Contraction/drug effects
Neurotransmitter Agents/pharmacology
Rats
Rats, Sprague-Dawley
Receptors, Cholinergic/chemistry/metabolism
Urocortins/isolation & purification/*pharmacology
Neurotransmitter Agents
Receptors, Cholinergic
Urocortins