T84 epithelial cells respond to 5-hydroxytryptamine when grown in serum-free media

The aim of this study was to establish the cause of insensitivity of T-84 human colonic epithelial cells to 5-hydroxytryptamine (5-HT). Monolayers of T-84 cells were placed in modified Ussing chambers for measurement of short-circuit current, an index of secretion. When grown in serum-supplemented media, T-84 cells gave secretory responses to acetylcholine and forskolin but not to 5-HT. When grown in AIM V serum-free media, T-84 cells responded-to 5-HT. Chromatographic analysis with fluorimetric detection showed high levels of 5-HT (1.8 mu M) in the serum. This contamination is probably responsible for subsequent desensitization of T-84 cells to 5-HT. (C) 2000 Elsevier Science B.V. All rights reserved.