Acute exposure of small intestine to ethanol

Gupta

J. Clin. Biochem. Nutr.

et al. 1994

SummaryEffect of chronic ethanol administration daily for 40 days together with 30% protein (HP) diet on microvillus membrane (MVM) glycosylation in rat intestine was studied. Ethanol administration to rats on a normal diet enhanced the hexose and sialic acid contents of brush borders but significantly reduced (p <0.05) membrane fucose levels. Feeding of the HP diet induced a generalized increase in MVM glycosylation. Ethanol feeding of rats maintained on the HP diet differently affected membrane glycosylation. Hexosamine content was enhanced, fucose and hexose contents were reduced, and sialic acid levels were unaltered under these conditions. The binding of 125I-wheat-germ agglutinin and 125I-peanut agglutinin to MVM was compatible with the chemical analysis of sugars in the various experimental groups. Incorporation of [14C] mannose or [ 14C ]glucosamine into MVM from different groups of rats revealed an increase in mannosylation but a decrease in glucosamine incorporation into MVM from ethanol-or HP-fed animals. Ethanol feeding along with HP diet enhanced the incorporation of labelled sugars into MVM compared with that of the HP-fed controls. Electrophoretic distribution of radiolabelled membrane glycoproteins from the different groups revealed that glycoproteins of Mr 60,000 were highly labelled. These results suggest that ethanol ingestion along with control or HP diet markedly modifies the intestinal MVM glycosylation but that these effects vary under different dietary regimens.

Section: Discussionmentioning

confidence: 99%

Effect of Chronic Ethanol Administration on Intestinal Microvillus Membrane Glycosylation in Rats Fed Rat Pellet Diet and Protein-Rich Diet.

Gupta

J. Clin. Biochem. Nutr.

et al. 1994

American Journal of Physiology-Gastrointestinal and Liver Physi

“…In humans ϳ10% of the ingested alcohol is absorbed by the gastric epithelium in a fasting state, while the largest fraction is absorbed in the proximal small intestine (18). It is therefore likely that the ethanol concentration in the proximal duodenum will be almost the same as that ingested (9,10). Previous experiments in our laboratory have shown that luminal perfusion with hydrochloric acid or hypo-as well as hypertonic solutions (30,31,41) increases duodenal epithelial paracellular permeability.…”

mentioning

confidence: 93%

Melatonin inhibits alcohol-induced increases in duodenal mucosal permeability in rats in vivo

Sommansson

Saudi

Nylander

et al. 2013

Sommansson A, Saudi WSW, Nylander O, Sjöblom M. Melatonin inhibits alcohol-induced increases in duodenal mucosal permeability in rats in vivo. Am J Physiol Gastrointest Liver Physiol 305: G95-G105, 2013. First published May 2, 2013; doi:10.1152/ajpgi.00074.2013.-Increased intestinal permeability is often associated with epithelial inflammation, leaky gut, or other pathological conditions in the gastrointestinal tract. We recently found that melatonin decreases basal duodenal mucosal permeability, suggesting a mucosal protective mode of action of this agent. The aim of the present study was to elucidate the effects of melatonin on ethanol-, wine-, and HCl-induced changes of duodenal mucosal paracellular permeability and motility. Rats were anesthetized with thiobarbiturate and a ϳ30-mm segment of the proximal duodenum was perfused in situ. Effects on duodenal mucosal paracellular permeability, assessed by measuring the blood-to-lumen clearance of 51 Cr-EDTA, motility, and morphology, were investigated. Perfusing the duodenal segment with ethanol (10 or 15% alcohol by volume), red wine, or HCl (25-100 mM) induced concentration-dependent increases in paracellular permeability. Luminal ethanol and wine increased, whereas HCl transiently decreased duodenal motility. Administration of melatonin significantly reduced ethanol-and wine-induced increases in permeability by a mechanism abolished by the nicotinic receptor antagonists hexamethonium (iv) or mecamylamine (luminally). Signs of mucosal injury (edema and beginning of desquamation of the epithelium) in response to ethanol exposure were seen only in a few villi, an effect that was histologically not changed by melatonin. Melatonin did not affect HClinduced increases in mucosal permeability or decreases in motility. Our results show that melatonin reduces ethanol-and wine-induced increases in duodenal paracellular permeability partly via an enteric inhibitory nicotinic-receptor dependent neural pathway. In addition, melatonin inhibits ethanol-induced increases in duodenal motor activity. These results suggest that melatonin may serve important gastrointestinal barrier functions.

“…However, during alcohol ingestion, the upper gastrointestinal tract (GIT) is exposed to concentrations of ethanol which are several times higher than those attained in other tissues [1]. This may explain numerous degenerative and inflammatory conditions and metabolic aberrations observed in GIT during chronic alcoholism [2]. Our earlier studies have shown that chronic ethanol feeding to rats results in altered enzyme activites The mucosal surface of the GIT is covered with a thick, protective, viscous, slippery gel, the mucus, which contains the gel forming glycoproteins called 'mucins'.…”

mentioning

confidence: 99%

Chronic Ethanol Feeding Affects Intestinal Mucus Lipid Composition and Glycosylation in Rats

2002

Ann Nutr Metab

Effect of chronic ethanol feeding on mucus lipid composition and glycosylation was investigated in rat intestine. Ethanol feeding to rats daily for 40 days enhanced cholesterol, phospholipids, triglyceride and cerebroside contents of intestinal mucus. Ethanol feeding exhibited a differential effect on various sugar contents of the mucus. Total hexose content was increased (42%) whereas hexosamines, sialic acid and fucose contents were reduced (p < 0.001). Results on incorporation of labeled sugars into mucus revealed an enhanced (p < 0.01) galactosylation and reduced (p < 0.01) glucosamination of glycoproteins. Separation of glycoproteins on SDS-PAGE showed that proteins of molecular weight >200, 118, 65 and 55 kD were affected. These were highly galactosylated and less glucosaminated in ethanol-fed animals compared to controls. Thus, ethanol feeding markedly alters the lipid composition and glycosylation process of intestinal mucus in rats. These alterations may be of pathological significance in view of the role of mucus in protection and adhesion of microorganisms.