Luminally released serotonin stimulates colonic motility and accelerates colonic transit in rats.

Published

Journal Article

Enterochromaffin (EC) cells of the epithelial cells release 5-HT into the lumen, as well as basolateral border. However, the physiological role of released 5-HT into the lumen is poorly understood. Concentrations of 5-HT in the colonic mucosa, colonic lumen, and feces were measured by HPLC in rats. To investigate whether intraluminal 5-HT accelerates colonic transit, 5-HT and (51)Cr were administered into the lumen of the proximal colon, and colonic transit was measured. To investigate whether 5-HT is released into the lumen, we used an ex vivo model of isolated vascularly and luminally perfused rat proximal colon. To investigate whether luminal 5-HT is involved in regulating stress-induced colonic motility, the distal colonic motility was recorded under the stress loading, and a 5-HT(3) receptor antagonist (ondansetron, 10(-6) M, 0.5 ml) was administered intraluminally of the distal colon. Tissue content of 5-HT in the proximal colon (15.2 +/- 4.3 ng/mg wet tissue) was significantly higher than that in the distal colon (3.3 +/- 0.7 ng/mg wet tissue), while fecal content and luminal concentration of 5-HT was almost the same between the proximal and distal colon. Luminal administration of 5-HT (10(-6)-10(-5) M) significantly accelerated colonic transit. Elevation of intraluminal pressure by 10 cmH(2)O significantly increased the luminal concentration of 5-HT but not the vascular concentration of 5-HT. Stress-induced stimulation of the distal colonic motility was significantly attenuated by the luminal administration of ondansetron. These results suggest that luminally released 5-HT from EC cells plays an important role in regulating colonic motility in rats.

Full Text

Duke Authors

Cited Authors

  • Tsukamoto, K; Ariga, H; Mantyh, C; Pappas, TN; Yanagi, H; Yamamura, T; Takahashi, T

Published Date

  • July 2007

Published In

Volume / Issue

  • 293 / 1

Start / End Page

  • R64 - R69

PubMed ID

  • 17442783

Pubmed Central ID

  • 17442783

International Standard Serial Number (ISSN)

  • 0363-6119

Digital Object Identifier (DOI)

  • 10.1152/ajpregu.00856.2006

Language

  • eng

Conference Location

  • United States