Electrogenic ion transport along the human duodenum in childhood

Background: To find reliable sites to study the effects of different secretagogues on electrogenic ion secretion, we investigated the secretion pattern in different parts of duodenum. Methods: Histologically normal 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'-monophosphate (cAMP), and acetylcholine (ACh) were studied with continuous measurements of the potential difference. Tissue resistance and generated current were calculated. Results: ACh induced secretion in the whole of duodenum, 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 secretion was only seen in the distal part. The fully expressed electrogenic chloride secretion was only seen at or distal to the duodenojejunal flexure. Our study shows that it is important to carefully define the localization of physiologic studies performed in the duodenum.