Rotavirus infection stimulates the Cl- reabsorption process across the intestinal brush-border membrane of young rabbits.
Rotavirus is a major cause of infantile gastroenteritis worldwide. However, the mechanisms underlying fluid and electrolyte secretion associated with diarrhea remain largely unknown. We investigated the hypothesis that loss of Cl(-) into the luminal contents during rotavirus infection may be caused by a dysfunction in the chloride absorptive capacity across the intestinal brush-border membrane (BBM). The luminal Cl(-) concentrations in the entire small intestine of young rabbits infected with lapine rotavirus decreased at 1 and 2 days postinfection (dpi), indicating net Cl(-) absorption. At 7 dpi, luminal Cl(-) concentrations were slightly increased, indicating a moderate net Cl(-) secretion. By using a rapid filtration technique, (36)Cl uptake across BBM was quantified by modulating the alkali-metal ion, electrical, chloride, and/or proton gradients. Rotavirus infection caused an identical, 127% +/- 24% increase in all Cl(-) uptake activities (Cl(-)/H(+) symport, Cl(-) conductance, and Cl(-)/anion exchange) observed across the intestinal BBM. The rotavirus activating effects on the symporter started at 1 dpi and persisted up to 7 dpi. Kinetic analyses revealed that rotavirus selectively affected the capacity parameter characterizing the symporter. We report the novel observation that rotavirus infection stimulated the Cl(-) reabsorption process across the intestinal BBM. We propose that the massive Cl(-) reabsorption in villi could partly overwhelm chloride secretion in crypt cells, which possibly increases during rotavirus diarrhea, the resulting imbalance leading to a moderate net chloride secretion.
Lorrot
Mathie
M
Institut National de la Santé et de la Recherche Médicale, Unité 510, Faculté de Pharmacie, Université de Paris XI, 92296 Châtenay-Malabry, France.
Martin
Sandra
S
Vasseur
Monique
M
D000818:Animals; D017920:Antiporters / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D005759:Gastroenteritis / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D007413:Intestinal Mucosa / Q000378:metabolism*; D017136:Ion Transport; D007700:Kinetics; D008871:Microvilli / Q000378:metabolism; D011817:Rabbits; D012400:Rotavirus Infections / Q000378:metabolism*
D017920:Antiporters; D002712:Chlorides; C114260:hydrogen-chloride symporter