Ion transport in the intestine.
OBJECTIVE
In recent years, the field of intestinal physiology has witnessed significant progress in our understanding of the expression and function of ion transport proteins and their genes under physiological and pathophysiological conditions. This review will present some of these most recent advances in the small intestinal ion transport mechanisms.


RESULTS
One of the new and exciting aspects of this field has been the integration of function and structure of several intestinal transport processes. This is well exemplified by the discussed intricacies of intestinal bicarbonate secretion as well as the role of scaffolding PDZ proteins interacting with several transporters. We also discuss some of the most recent data pointing to the role of ion transporters in the pathogenesis of inflammation-associated diarrhea and their potential role in the maintenance of epithelial integrity.


CONCLUSIONS
Mouse models deficient in some of the key genes encoding ion transporters and their adapter proteins continue to provide important clues into intestinal transport processes. Several of the new in-vivo findings revise or complement past paradigms, many of which were derived from in-vitro approaches. New data on the interdependent functions of multiple transporters, as exemplified here by intestinal bicarbonate secretion, increase the complexity of the intestinal ion transport mechanisms and continue to contribute to a more integrated view of the transport phenomena in the gut. Data from patients and mouse models of intestinal inflammation also increase our understanding of the pathophysiology of inflammation-associated diarrhea.
Kiela
Pawel R
PR
Department of Pediatrics, Steele Children's Research Center, University of Arizona Health Science Center, Tucson, AZ 85724, USA.
Ghishan
Fayez K
FK
D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D004386:Duodenum / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D017136:Ion Transport / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D023421:Models, Animal; D010750:Phosphoproteins / Q000502:physiology; D017923:Sodium-Hydrogen Exchangers / Q000502:physiology
D001639:Bicarbonates; D026901:Membrane Transport Proteins; D010750:Phosphoproteins; D017923:Sodium-Hydrogen Exchangers; C093376:sodium-hydrogen exchanger regulatory factor