X-ray microanalysis of intestinal chloride transport in vitro and in vivo

Chloride secretion from crypt cells in mouse duodenum or jejunum was invest igated in in vivo and in vitro models by electron probe X-ray microanalysis . IBMX-induced chloride secretion could not be demonstrated in vivo, presum ably because of competing systemic effects. However, chloride secretion cou ld be induced by 300 mu M IBMX in vitro. The best results were obtained und er the following conditions: a long preincubation of the tissue slices in h igh potassium or saline buffer (preferably in high potassium buffer), oxyge nated with 95% O-2 and 5% CO2, at low temperature (4 degrees C), followed b y IBMX stimulation in saline buffer at 37 degrees C. Chloride efflux was ac companied by efflux of Na and K. (C) 2000 Wiley-Liss, Inc.