Converging effects of a Bifidobacterium and Lactobacillus probiotic strain on mouse intestinal physiology

2014 ◽  
Vol 307 (2) ◽  
pp. G241-G247 ◽  
Author(s):  
Kevin W. Lomasney ◽  
John F. Cryan ◽  
Niall P. Hyland
Keyword(s):  
Ion Transport ◽  
Water Content ◽  
Short Circuit ◽  
Intestinal Transit ◽  
Current Response ◽  
Dependent Manner ◽  
Small Intestinal Transit ◽  
Ussing Chambers ◽  
Small Intestinal

Evidence has grown to support the efficacy of probiotics in the management of gastrointestinal disorders, many of which are associated with dysregulated fluid and electrolyte transport. A growing body of evidence now suggests that the host microbiota and probiotics can influence intestinal ion transport and that these effects often occur in a strain-dependent manner. In this study, we sought to investigate the effects of two therapeutically relevant organisms, Bifidobacterium infantis 35624 and Lactobacillus salivarius UCC118, on small intestinal transit, fecal output and water content, transepithelial resistance (TER), and colonic secretomotor function. Mice fed either strain displayed significantly reduced small intestinal transit in vivo, though neither strain influenced fecal pellet output or water content. Colon from mice fed both organisms displayed increased colonic TER, without a concomitant change in the gene expression of the tight junction proteins claudin 1 and occludin. However, L. salivarius UCC118 selectively inhibited neurally evoked ion secretion in tissues from animals fed this particular probiotic. Consistent with this finding, the neurotoxin tetrodotoxin (TTx) significantly inhibited the short-circuit current response induced by L. salivarius UCC118 following addition to colonic preparations in Ussing chambers. Responses to B. infantis 35624 also displayed sensitivity to TTx, although to a significantly lesser degree than L. salivarius UCC118. Both strains similarly inhibited cholinergic-induced ion transport after addition to Ussing chambers. Taken together, these data suggest that B. infantis 35624 and L. salivarius UCC118 may be indicated in disorders associated with increased small intestinal transit, and, in particular for L. salivarius UCC118, neurally mediated diarrhea.

NaCl transport across equine proximal colon and the effect of endogenous prostanoids

1990 ◽  
Vol 259 (1) ◽  
pp. G62-G69 ◽  
Author(s):  
L. L. Clarke ◽  
R. A. Argenzio
Keyword(s):  
Ion Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Proximal Colon ◽  
Nacl Transport ◽  
Apparent Lack ◽  
Ussing Chambers ◽  
Cl Secretion

In contrast to in vivo findings, the equine proximal colon fails to demonstrate significant net absorption of Na+ and Cl- under in vitro conditions. The present study was undertaken to determine if endogenous prostanoids are responsible for this apparent lack of ion transport. Proximal colonic tissues from ponies were preincubated in either normal Ringer solution or in Ringer containing 1 microM indomethacin and studied in Ussing chambers containing these solutions. Untreated colonic mucosa demonstrated negligible Na(+)-Cl- absorption in the basal state. In contrast, indomethacin-treated colon significantly absorbed Na+ and Cl-, primarily as the result of an equivalent increase in the mucosal-to-serosal flux of these ions. Preincubation of proximal colon in 0.1 mM ibuprofen-treated Ringer yielded similar results. Treatment of indomethacin colon with 1 mM mucosal amiloride eliminated net Na(+)-Cl- absorption without affecting the short-circuit current (Isc). The Isc in control tissue was significantly greater than in indomethacin-treated tissue and was reduced by 0.1 mM serosal furosemide. Serosal addition of 0.1 microM prostaglandin E2 or 10 mM serosal plus mucosal theophylline to indomethacin-treated tissues abolished net Na(+)-Cl- absorption and increased the Isc to levels indistinguishable from control. In contrast, control tissues were essentially unaffected by these secretagogues. These findings indicated that Na(+)-Cl- absorption in equine proximal colon was electroneutral (possibly involving Na(+)-H+ exchange) and that the tissue was capable of electrogenic Cl- secretion. However, under the in vitro conditions, basal ion transport was dominated by endogenous prostanoids that abolished Na(+)-Cl- absorption and elicited near-maximal electrogenic Cl- secretion.

Histamine stimulates ion transport by dog pancreatic duct epithelial cells through H1receptors

1998 ◽  
Vol 275 (1) ◽  
pp. G76-G84 ◽  
Author(s):  
Toan D. Nguyen ◽  
Charles N. Okolo ◽  
Mark W. Moody
Keyword(s):  
Epithelial Cells ◽  
Ion Transport ◽  
Receptor Antagonist ◽  
Pancreatic Duct ◽  
Direct Action ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ussing Chambers

Histamine affects pancreatic secretion, but its direct action on ion transport by pancreatic duct epithelial cells (PDEC) has not been defined. We now characterize the secretory effects of histamine on cultured, well-differentiated, and nontransformed dog PDEC. Histamine stimulated, in a concentration-dependent manner (1–100 μM), a cellular125I−efflux that was inhibited by 500 μM 5-nitro-2-(3-phenylpropylamino)benzoic acid, 2.5 mM diphenylamine-2-carboxylate, and 500 μM DIDS and thus mediated through Ca2+-activated Cl− channels. Histamine-stimulated125I−efflux was 1) inhibited by 100 μM diphenhydramine, an H1receptor antagonist, 2) resistant to 1 mM cimetidine, an H2 receptor antagonist, 3) not reproduced by 1 mM dimaprit, an H2 agonist, and 4) inhibited by 50 μM 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid-AM, a Ca2+ chelator, suggesting that it was mediated through H1 receptors acting via increased cytosolic Ca2+. Histamine also stimulated a86Rb+efflux that was sensitive to 100 nM charybdotoxin and thus mediated through Ca2+-activated K+ channels. When PDEC monolayers were studied in Ussing chambers, a short-circuit current of 21.7 ± 3.1 μA/cm2 was stimulated by 100 μM histamine. This effect was inhibited by diphenhydramine but not cimetidine, was not reproduced with dimaprit, and was observed only after serosal addition of histamine, suggesting that it was mediated by basolateral H1 receptors on PDEC. In conclusion, histamine, acting through basolateral H1 receptors, activates both Ca2+-activated Cl− and K+ channels; in this manner, it may regulate PDEC secretion in normal or inflamed pancreas.

Prolonged interferon-γ exposure decreases ion transport, NKCC1, and Na+-K+-ATPase expression in human intestinal xenografts in vivo

2004 ◽  
Vol 286 (1) ◽  
pp. G157-G165 ◽  
Author(s):  
Lone S. Bertelsen ◽  
Lars Eckmann ◽  
Kim E. Barrett
Keyword(s):  
Ion Transport ◽  
Prolonged Exposure ◽  
Intestinal Inflammation ◽  
Interferon Γ ◽  
Α Subunit ◽  
Ussing Chambers ◽  
Epithelial Cell Lines ◽  
Ifn Γ ◽  
Small Intestinal

IFN-γ is elevated in intestinal inflammation and alters barrier and transport functions in human colonic epithelial cell lines, but its effects on normal human small intestinal epithelium in vivo are poorly defined. We investigated effects of prolonged IFN-γ exposure on ion transport and expression of transporters by using human fetal small intestinal xenografts. Xenograft-bearing mice were injected with IFN-γ, and 24 h later xenografts were harvested and mounted in Ussing chambers. Baseline potential difference (PD) was not affected by IFN-γ treatment. However, conductance was enhanced and agonist-stimulated ion transport was decreased. IFN-γ also decreased expression of the Na+-K+-2Cl- cotransporter and the α-subunit of Na+-K+-ATPase compared with controls, whereas levels of the calcium-activated Cl- channel and CFTR were unaltered. Thus prolonged exposure to IFN-γ leads to decreased ion secretion due, in part, to decreased ion transporter levels. These findings demonstrate the implications of elevated IFN-γ levels in human small intestine and validate the human intestinal xenograft as a model to study chronic effects of physiologically relevant stimuli.

Protein kinase C potentiates cAMP-stimulated mouse duodenal mucosal bicarbonate secretion in vitro

2004 ◽  
Vol 286 (5) ◽  
pp. G814-G821 ◽  
Author(s):  
Bi-Guang Tuo ◽  
Jimmy Y. C. Chow ◽  
Kim E. Barrett ◽  
Jon I. Isenberg
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Duodenal Mucosa ◽  
Bicarbonate Secretion ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ussing Chambers ◽  
Duodenal Bicarbonate Secretion

PKC has been shown to regulate epithelial Cl- secretion in a variety of models. However, the role of PKC in duodenal mucosal bicarbonate secretion is less clear. We aimed to investigate the role of PKC in regulation of duodenal mucosal bicarbonate secretion. Bicarbonate secretion by murine duodenal mucosa was examined in vitro in Ussing chambers using a pH-stat technique. PKC isoform expression and activity were assessed by Western blotting and in vitro kinase assays, respectively. PMA (an activator of PKC) alone had no effect on duodenal bicarbonate secretion or short-circuit current ( Isc). When PMA and dibutyryl-cAMP (db-cAMP) were added simultaneously, PMA failed to alter db-cAMP-stimulated duodenal bicarbonate secretion or Isc ( P > 0.05). However, a 1-h preincubation with PMA potentiated db-cAMP-stimulated duodenal bicarbonate secretion and Isc in a concentration-dependent manner (from 10-8 to 10-5M) ( P < 0.05). PMA preincubation had no effects on carbachol- or heat-stable toxin-stimulated bicarbonate secretion. Western blot analysis revealed that PKCα, -γ, -ϵ, -θ, -μ, and -ι/λ were expressed in murine duodenal mucosa. Ro 31–8220 (an inhibitor active against PKCϵ, -α, -β, and -γ), but not Gö 6983 (an inhibitor active against PKCα, -γ, -β, and -δ), reversed the potentiating effect of PMA on db-cAMP-stimulated bicarbonate secretion. PMA also time- and concentration-dependently increased the activity of PKCϵ, an effect that was prevented by Ro 31–8220 but not Gö 6983. These results demonstrate that activation of PKC potentiates cAMP-stimulated duodenal bicarbonate secretion, whereas it does not modify basal secretion. The effect of PKC on cAMP-stimulated bicarbonate secretion is mediated by the PKCϵ isoform.

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