Please Note:

The Open Access Repository will be moving to a new authentication system on the 1st of November.

From this date onwards, account holders will be required to login using their University of Tasmania credentials.
If your current repository username differs from your University username, please email so we can update these details on your behalf.

Due to the change, there will be a short outage of the repository from 9am on the morning of the 1st of November

Open Access Repository

Comparison of 5-HT4 and 5-HT7 receptor expression and function in the circular muscle of the human colon


Downloads per month over past year

Irving, HR and Tan, YY and Tochon-Danguy, N and Liu, H and Chetty, N and Desmond, PV and Pouton, CW and Coupar, IM (2007) Comparison of 5-HT4 and 5-HT7 receptor expression and function in the circular muscle of the human colon. Life Sciences, 80 (13). pp. 1198-1205. ISSN 0024-3205

[img] PDF
4258.pdf | Request a copy
Full text restricted


Serotonin receptors are potential targets for treating functional bowel disorders. This study investigated the functional roles and expression of the 5-HT4 and the 5-HT7 receptor, which coexist in human colon circular smooth muscle. 5-HT3 receptor expression was also investigated. Part of the relaxant response to 5-HT was due to activation of 5-HT4 receptors as the apparent pKB value of the selective 5-HT4 antagonist, GR 113808, was 9.36. 5-HT4 mRNA levels were low in five tissues and undetectable in four others, but all responded to 5-HT with an EC50 value of 102.54 ± 19.32 nM. The contribution of 5-HT7 receptors to the response was not readily demonstrated using the selective 5-HT7 antagonist, SB-269970, as its apparent pKB value of 7.19 (5-HT4 block with 1 μM GR 113808) was lower than the value obtained using the 5-HT7 guinea pig ileum assay (8.62). Nevertheless, the 5-HT7 receptor was expressed more consistently than the 5-HT4, but at similar levels. The 5-HT3Ashort and 5-HT3B subunits were co-expressed at similar levels, but the 5-HT3Along subunit was detected in only five of the nine samples tested. The findings show that 5-HT4-induced relaxation occurs at low to undetectable levels of tissue mRNA, as measured by qPCR. Although 5-HT7 receptor mRNA is detected at low, but consistent levels, the functional activity of this receptor is not readily identified given the currently available drugs.

Item Type: Article
Keywords: Serotonin receptors; 5-HT3 receptors; 5-HT4 receptors; 5-HT7 receptors; Gastrointestinal tract; Human tissue; Colonic smooth muscle
Journal or Publication Title: Life Sciences
Publisher: Pergamon-Elsevier Science Ltd
Page Range: pp. 1198-1205
ISSN: 0024-3205
Identification Number - DOI: 10.1016/j.lfs.2006.12.025
Additional Information:

The definitive version is available at

Date Deposited: 07 Apr 2008 14:29
Last Modified: 18 Nov 2014 03:35
Item Statistics: View statistics for this item

Actions (login required)

Item Control Page Item Control Page