Referenced in: none

Automatically associated channels: ClC4 , ClCA1 , Kv7.1

Title: Segmental heterogeneity of electrogenic secretions in human ascending colon and rectum.

Authors: Jung Ho Park, Poong-Lyul Rhee, Jun Haeng Lee, Jae Jun Kim, Jong Chul Rhee, Sung Joon Kim, Jiyeon Lee

Journal, date & volume: , 2006 May , 21, 357-64

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/16158276

Abstract
We have attempted to ascertain putative segmental differences in the secretory responses of the human ascending colon and rectum.From the mucosal biopsy samples of two segments, the short-circuit current (I(sc)) and tissue resistance (R(te)) were compared under control conditions, as well as after the induction of secretion, using a modified Ussing chamber. We also performed semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to detect and quantify transport proteins.The spontaneous I(sc) in the ascending colon was found to be greater than that in the rectum (P<0.01), whereas isobutylmethylxanthine/forskolin and carbachol (CCh) induced a greater rise in I(sc) in the rectum than in the ascending colon (P<0.05). When coupled with indomethacin pretreatment, the increase in Delta I(sc) after the addition of CCh and forskolin was significant as compared to that observed without pretreatment (P<0.05). However, in the rectum, the secretory response to CCh and forskolin was abolished to a significant degree by indomethacin (P<0.05). Moreover, these indomethacin-induced changes were reversed by the addition of PGE2. Upon semiquantitative RT-PCR analysis, the amounts of cystic fibrosis transmembrane regulator, KCNQ1, and CLCA1 mRNAs were not found to be different between the two segments.There was a clear segmental heterogeneity with regard to electrogenic secretion in the human colon, and this difference can be explained by differences in the ascending colon and rectum.