Distribution of 5-HT3, 5-HT4, and 5-HT7 receptors along the human colon

Nor S Yaakob, Kenneth A Chinkwo, Navinisha Chetty, Ian M Coupar, Helen R Irving

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11 Citations (Scopus)

Abstract

Background/Aims: Several disorders of the gastrointestinal tract are associated with abnormal serotonin (5-HT) signaling or metabolism where the 5-HT3 and 5-HT4 receptors are clinically relevant. The aim was to examine the distribution of 5-HT3, 5-HT4, and 5-HT7 receptors in the normal human colon and how this is associated with receptor interacting chaperone 3, G protein coupled receptor kinases, and protein LIN-7 homologs to extend previous observations limited to the sigmoid colon or the upper intestine.
Methods: Samples from ascending, transverse, descending, and sigmoid human colon were dissected into 3 separate layers (mucosa, longitudinal, and circular muscles) and ileum samples were dissected into mucosa and muscle layers (n = 20). Complementary DNA was synthesized by reverse transcription from extracted RNA and expression was determined by quantitative or end point polymerase chain reaction.
Results: The 5-HT3 receptor subunits were found in all tissues throughout the colon and ileum. The A subunit was detected in all samples and the C subunit was expressed at similar levels while the B subunit was expressed at lower levels and less frequently. The 5-HT3 receptor E subunit was mainly found in the mucosa layers. All splice variants of the 5-HT4 and 5-HT7 receptors were expressed throughout the colon although the 5-HT4 receptor d, g, and i variants were expressed less often.
Conclusions: The major differences in 5-HT receptor distribution within the human colon are in relation to the mucosa and muscular tissue layers where the 5-HT3 receptor E subunit is predominantly found in the mucosal layer which may be of therapeutic relevance.
Original languageEnglish
Pages (from-to)361-369
Number of pages9
JournalJournal of Neurogastroenterology and Motility
Volume21
Issue number3
DOIs
Publication statusPublished - 2015

Keywords

  • Colon
  • G protein coupled receptor kinases
  • Ileum
  • Receptors
  • Serotonin

Cite this

Yaakob, N. S., Chinkwo, K. A., Chetty, N., Coupar, I. M., & Irving, H. R. (2015). Distribution of 5-HT3, 5-HT4, and 5-HT7 receptors along the human colon. Journal of Neurogastroenterology and Motility, 21(3), 361-369. https://doi.org/10.5056/jnm14157