Ricinoleic acid stimulation of active anion secretion in colonic mucosa of the rat.

Phorbol 12,13-dibutyrate (PDB) stimulates electrogenic anion secretion in rabbit and chicken distal ileum. The 50% effective dose in each case was 15 nM, and the maximal short-circuit current (Isc) responses seen at 10(-6) M were 20 and 140 microA/cm2, respectively. Isc was also stimulated by the diacylglycerol 1-oleoyl-2-acetyl glycerol (10(-5) M) but not by the inactive phorbol ester analogue 4 alpha-phorbol 12,13-didecanoate. Removal of Ca from the serosal bathing medium and pretreatment of tissues with atropine (10(-6) M) or tetrodotoxin (2 X 10(-7) M) did not affect PDB-stimulated responses. PDB also did not alter basal intracellular free Ca levels in isolated chicken enterocytes loaded with quin 2 or basal adenosine 3',5'-cyclic monophosphate levels in intact tissues from rabbit and chicken. In the presence of PDB, Ca- and phospholipid-dependent phosphorylation of several proteins in particulate and soluble fractions from isolated chicken enterocytes were seen. Pretreatment of chicken and rabbit tissues with indomethacin or mepacrine inhibited the Isc responses to PDB and carbamylcholine, suggesting a role for prostaglandins. These results suggest that electrogenic anion secretion stimulated by phorbol esters and diacylglycerol may be mediated by activation of protein kinase C.

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Modulation of gut mucosal biofilms

British Journal Of Nutrition ◽

10.1079/bjn20041346 ◽

2005 ◽

Vol 93 (S1) ◽

pp. S35-S40 ◽

Cited By ~ 72

Author(s):

Brigitta Kleessen ◽

Michael Blaut

Keyword(s):

Colonic Mucosa ◽

Mucosal Barrier ◽

Mucus Layer ◽

Faecal Flora ◽

New Approach ◽

Serovar Typhimurium ◽

Health Promoting ◽

Gut Mucosal Barrier ◽

Induced Changes ◽

Stimulation Of

Non-digestible inulin-type fructans, such as oligofructose and high-molecular-weight inulin, have been shown to have the ability to alter the intestinal microbiota composition in such a way that members of the microbial community, generally considered as health-promoting, are stimulated. Bifidobacteria and lactobacilli are the most frequently targeted organisms. Less information exists on effects of inulin-type fructans on the composition, metabolism and healthrelated significance of bacteria at or near the mucosa surface or in the mucus layer forming mucosa-associated biofilms. Using rats inoculated with a human faecal flora as an experimental model we have found that inulin-type fructans in the diet modulated the gut microbiota by stimulation of mucosa-associated bifidobacteria as well as by partial reduction of pathogenicSalmonella enterica subsp. entericaserovar Typhimurium and thereby benefit health. In addition to changes in mucosal biofilms, inulin-type fructans also induced changes in the colonic mucosa stimulating proliferation in the crypts, increasing the release of mucins, and altering the profile of mucin components in the goblet cells and epithelial mucus layer. These results indicate that inulin-type fructans may stabilise the gut mucosal barrier. Dietary supplementation with these prebiotics could offer a new approach to supporting the barrier function of the mucosa.

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