ELECTROGENIC ION-TRANSPORT ALONG THE HUMAN DUODENUM IN CHILDHOOD

Background: To find reliable sites to study the effects of different s ecretagogues on electrogenic ion secretion, we investigated the secret ion pattern in different parts of duodenum. Methods: Histologically no rmal routine intestinal biopsy specimens from children were mounted in a modified Ussing chamber. The secretory responses to prostaglandin E -2 (PGE(2)), aminophylline, dibutyryl cyclic adenosine 5'-monophosphat e (cAMP), and acetylcholine (ACh) were studied with continuous measure ments of the potential difference. Tissue resistance and generated cur rent were calculated. Results: ACh induced secretion in the whole of d uodenum, although the secretory response was augmented distally. PGE(2 ) and cAMP induced significant secretion only in the distal duodenum, Conclusions: The ACh-induced, calcium-mediated, electrogenic secretion was expressed along the whole duodenum, whereas the cAMP-mediated sec retion was only seen in the distal part. The fully expressed electroge nic chloride secretion was only seen at or distal to the duodenojejuna l flexure. Our study shows that it is important to carefully define th e localization of physiologic studies performed in the duodenum.