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Urea transport across the gastrointestinal tract involves transporters of the urea transporter-B group, the regulation of which is poorly understood. The classical stimulatory effect of CO(2) and the effect of short-chain fatty acids (SCFA) on the ruminal recycling of urea were investigated by using Ussing chamber and microelectrode techniques with isolated(More)
The potential difference (PD)-dependent component of transcellular Mg(2+) uptake in sheep rumen epithelium was studied. Unidirectional (28)Mg(2+) fluxes were measured at various transepithelial PD values, and the unidirectional mucosal-to-serosal (28)Mg(2+) flux (J(Mg)(ms)) was correlated with the PD across the apical membrane (PD(a)) determined by mucosal(More)
Ammonia is an abundant fermentation product in the forestomachs of ruminants and the intestine of other species. Uptake as NH3 or NH4+ should modulate cytosolic pH and sodium-proton exchange via Na+/H+ exchanger (NHE). Transport rates of Na+, NH4+, and NH3 across the isolated rumen epithelium were studied at various luminal ammonia concentrations and pH(More)
Unidirectional 22Na+ and 36Cl- fluxes were determined in short-circuited, stripped rumen mucosa from sheep by using the Ussing chamber technique. In both CO2/HCO3(-)-containing and CO2/HCO3(-)-free solutions, replacement of gluconate by short-chain fatty acids (SCFA, 39mM) significantly enhanced mucosal-to-serosal Na+ absorption without affecting the Cl-(More)
High potassium diets lead to an inverse regulation of sodium and magnesium absorption in ruminants, suggesting some form of cross talk. Previous Ussing chamber experiments have demonstrated a divalent sensitive Na(+) conductance in the apical membrane of ruminal epithelium. Using patch-clamped ruminal epithelial cells, we could observe a divalent sensitive,(More)
We tested the hypothesis that the dietary energy-dependent alterations of the rumen papillae size are accompanied by corresponding changes in systemic insulin-like growth factor (IGF)-1 concentration and in rumen papillary IGF type 1 receptors (IGF-1R). Young male goats (n=24) were randomly allocated to two groups (n=12) and fed a high level (HL)(More)
Net Mg(2+) absorption from the rumen is mainly mediated by a transcellular pathway, with the greater part (62%) being electrically silent. To investigate this component of Mg(2+) transport, experiments were performed with isolated ruminal epithelial cells (REC). Using the fluorescent indicators mag-fura 2, sodium-binding benzofuran isophthalate, and 2',(More)
Probiotics have shown positive effects on gastrointestinal diseases; they have barrier-modulating effects and change the inflammatory response towards pathogens in studies in vitro. The aim of this investigation has been to examine the response of intestinal epithelial cells to Enterococcus faecium NCIMB 10415 (E. faecium), a probiotic positively affecting(More)
Increasing ruminal K concentration impairs active Mg transport across the forestomach epithelium of ruminants. We used Ussing chamber and microelectrode techniques to test the hypothesis that high mucosal K decreases the driving force for Mg2+ uptake by depolarizing the apical membrane. Serosal Ba enhanced net 42K secretion. Under open-circuit conditions,(More)
The effects of luminal hyperosmolarity on Na and Cl transport were studied in rumen epithelium of sheep. An increase of luminal osmotic pressure with mannitol (350 and 450 mosm/l) caused a significant increase of tissue conductance, G (T), which is linearly correlated with flux rates of (51)Cr-EDTA and indicates an increase of passive permeability. Studies(More)