The Effect of Galanin on Colonic Motility in Isolated, Vascularly Perfused Rat Colon

Chin, Young Joo; Leem, Joung Muk; Chae, Hee Bok; Park, Seon Mee; Youn, Sei Jin

Abstract

BACKGROUND/AIMS: Galanin is distributed in enteric nerve terminals throughout the gastrointestinal tract. However, the effect of galanin on colonic motility in isolated colon is still unknown. Using isolated, vascularly perfused rat colon, we investigated the role of galanin on colonic motility, the difference in the effect of galanin between proximal and distal colon, and the innervation of the action of galanin on colonic motility (cholinergic or adrenergic input). METHODS: An isolated rat colon was placed in temperature-controlled water bath and vascularly perfused with Krebs solution. After a controlled period, galanin was administered intraarterially and the intraluminal pressure was monitored via microtip catheter pressure transducers at the proximal and distal colon. After pretreatment of phentolamine, propranolol, hexamethonium or atropine, respectively, galanin was infused at a concentration of 240 pM and intraluminal pressure was monitored. The contractile response was expressed as % changes of motility indices over basal period. RESULTS: Galanin significantly increased colonic motility (p<0.01). The contractile response was more potent at the distal colon but the difference was statistically insignificant (p>0.05). The stimulating effect was not inhibited by phentolamine, propranolol, hexamethonium but significantly inhibited by atropine. CONCLUSIONS: Galanin increases rat colonic motility and the action of galanin is influenced by cholinergic input.