title: Diffusion coefficient in native mucus gel of rat small intestine.
abstract: The diffusion coefficients of [3H] water, urea, benzoic acid, antipyrine, aminopyrine, alpha-methyl-glucoside, L-phenylalanine and of hydrogen ions were measured at 38 degrees C in native mucus gel from rat small intestine. The diffusion in the gel was reduced to 37-53% (for hydrogen ions to 7%) compared with buffer solution. In addition, the buffering capacity of the gel retarded the permeation of hydrogen ions before a steady state flux was attained. A model calculation revealed that in the preparation a gel layer of 80 microns thickness represents 23% of the total permeation resistance for substances with high epithelial permeability. The aqueous part of the pre-epithelial diffusion resistance amounts to 77% of the total resistance.
authors.affiliation: Abteilung für Molekularpharmakologie, Universität Tübingen, FRG.
authors.forename: D
authors.initials: D
authors.lastname: Winne
authors.forename: W
authors.initials: W
authors.lastname: Verheyen
mesh_terms: D000632:Aminopyrine / Q000737:chemistry*; D000818:Animals; D000983:Antipyrine / Q000737:chemistry*; D001565:Benzoates / Q000737:chemistry*; D019817:Benzoic Acid; D002021:Buffers; D004058:Diffusion; D005782:Gels; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000502:physiology*; D008297:Male; D010539:Permeability; D010649:Phenylalanine / Q000737:chemistry*; D051381:Rats; D011919:Rats, Inbred Strains; D014508:Urea / Q000737:chemistry*
chemical_list: D001565:Benzoates; D002021:Buffers; D005782:Gels; D000632:Aminopyrine; D010649:Phenylalanine; D019817:Benzoic Acid; D014508:Urea; D000983:Antipyrine