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  • Deoxycholate  (3)
  • Tetrodotoxin  (3)
  • Colonic mucosa  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Transfer of sodium and water through isolated rat colonic mucosa under the influence of deoxycholate and oxyphenisatin (1977)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 297 (1977), S. 185-190 
    Details
    ISSN: 1432-1912
    Keywords: Isolated rat colon ; Sodium transfer ; Water transfer ; Oxyphenisatin ; Deoxycholate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The influence of oxyphenisatin (OP), a diphenolic laxative, and deoxycholate (DC) on the transfer of sodium and water in an everted sac preparation of stripped rat colon was investigated. 2. OP (10−5 M, mucosal side) and DC (3×10−4 M, mucosal side) completely blocked net water and sodium absorption. Net movements from the serosal to the mucosal side could not be induced by higher concentrations of the drugs. 3. Unidirectional sodium movements in both directions were increased by OP and DC. 4. The effect of DC on the sodium flux from the serosal to the mucosal side was reversible. 5. The potassium content of the mucosal epithelium was not changed by DC and OP. 6. The integrity of the epithelium, as judged by light microscopy, was not disturbed by either drug under the experimental conditions. 7. It is concluded that DC and OP do not interfere with active transport mechanisms but increase the permeability of the epithelium to sodium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00499929
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  • 2
    Electronic Resource
    Electronic Resource
    Pathway of sodium moving from blood to intestinal lumen under the influence of oxyphenisatin and deoxycholate (1976)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 293 (1976), S. 31-37 
    Details
    ISSN: 1432-1912
    Keywords: Colonic mucosa ; Oxyphenisatin ; Deoxycholate ; Sodium ; Intercellular pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The transfer of 51CrEDTA and inulinsubstances which are distributed only in the extracellular space-across the rat colonic mucosa in vivo is increased by oxyphenisatin O (3.5 · 10−5 M) and deoxycholate D (3 · 10−3 M). 2. O and D do not change the size of the intra- and extracellular fluid compartments of the mucosa as measured with 51CrEDTA from the blood side. The sodium and potassium content of the mucosal tissue is not altered. Therefore the calculated intracellular concentrations of sodium and potassium remain constant. 3. The time course of the 22Na uptake into the mucosal epithelium is not influenced by O and D up to 5 min after i.v. injection. The specific activity of sodium, however, in the luminal fluid increases under the influence of O (twofold) and D (fivefold). The uptake of 22Na into the mucosal tissue after administration of 22Na into the intestinal lumen is not changed in presence of O and D. 4. We conclude that the net transport of sodium and water from blood to lumen under the influence of O and D occurs mainly via the intercellular way.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00498868
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  • 3
    Electronic Resource
    Electronic Resource
    Strontium transport in the rat colon (1987)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 335 (1987), S. 91-96 
    Details
    ISSN: 1432-1912
    Keywords: Colonic mucosa ; Strontium transport ; Relation to calcium transport ; 1.25-Dihydroxyvitamin D3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Concentration dependence of strontium (Sr) fluxes across the colon ascendens and descendens of the rat were measured in a modified Ussing-chamber. Mucosa (m) to serosa (s) and s to m Sr fluxes across both colonic segments were linearly related to the Sr concentration from 0.125 mmol/l to 10 mmol/l. In the colon ascendens m to s Sr fluxes were slightly higher than the fluxes in the opposite direction, resulting in net Sr absorption. In the colon descendens s to m fluxes were higher than the ms fluxes, resulting in net Sr secretion. Neither Sr nor calcium (Ca) showed a concentration dependent interaction with respect to their unidirectional fluxes in both parts of the colon. Only in the colon ascendens Sr at the highest concentration (10 mmol/l) inhibited m to s calcium transport. Experiments, in which the voltage dependence of the unidirectional Sr fluxes was measured confirmed the results obtained from the concentration dependence: (1) The unidirectional fluxes of Sr across the colon ascendens and descendens were totally voltage dependent, i.e. diffusive. (2) In the colon descendens the voltage dependence of the s to m flux was steeper than the flux from m to s. It is hypothesized that this prevalence is caused by an anomalous solvent drag effect. 1.25-Dihydroxyvitamin D3 [1.25 (OH)2D3] stimulated m to s calcium flux in the colon descendens but had no effect on Sr flux. The results demonstrate that Sr and Ca in the rat colon are transported by different mechanisms. In contrast to the Ca transport the Sr flux is only diffusive and insensitive to 1.25 (OH)2D3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00165042
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  • 4
    Electronic Resource
    Electronic Resource
    Phospholipase A2 and mediation of the activation of short-circuit current in the rat colonic mucosa (1991)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 652-658 
    Details
    ISSN: 1432-1912
    Keywords: Rat colon ; Ion transport ; Melittin ; Prostaglandins ; Tetrodotoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Melittin (0.5–2 μg ml−1) increased the short-circuit current (Isc) in mucosa-submucosa and mucosa preparations of the rat colon descendens in a dose-dependent manner. In the preparation with the submucosal plexus, quinacrine and indomethacin completely blocked the effect of melittin, indicating activation of phospholipase A2 and production of prostaglandins induced by the drug. The melittin response was also partially sensitive to the lipoxygenase inhibitor, nordihydroguaiaretic acid. Complete inhibition by tetrodotoxin and atropine gives evidence for the involvement of cholinergic neurons in the mediation of the response induced by melittin. In contrast, in the preparation without the submucosal plexus the effect of melittin was only partially inhibited by quinacrine, indomethacin, or by neuronal blockers, suggesting direct interactions of melittin with the epithelium in addition. The effect of melittin resembles to the action of bradykinin, which is neuronally mediated and quinacrine-sensitive in the mucosa-submucosa preparation, and quinacrine-resistant and not neuronally mediated in the mucosa preparation. In the mucosa-submucosa preparation, the melittin response is even partially sensitive to the bradykinin receptor antagonist [D-Phe7]-bradykinin. The results provide evidence for the presence of a quinacrine-sensitive phospholipase A2 in the preparation with and that without the submucosa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00184298
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  • 5
    Electronic Resource
    Electronic Resource
    Comparative study of the effect of cholera toxin and sodium deoxycholate on the paracellular permeability and on net fluid and electrolyte transfer in the rat colon (1980)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 312 (1980), S. 91-97 
    Details
    ISSN: 1432-1912
    Keywords: Rat colon mucosa ; Cholera toxin ; Deoxycholate ; Permeability ; Morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The effect of deoxycholate and cholera toxin on the transfer of water, sodium, potassium and chloride and on mucosal permeability was studied in perfusion experiments on rat colon in vivo. The influence of both secretagogues on surface morphology was assessed by scanning electron microscopy. 2. Deoxycholate turned the absorption of water, sodium and chloride to secretion and enhanced potassium secretion. Cholera toxin induced water and sodium secretion, inhibited chloride absorption and enhanced potassium secretion. 3. Deoxycholate increased reversibly the mucosal permeability as measured by the colonic clearance of 51CrEDTA and glucose, whereas cholera toxin decreased the colonic 51CrEDTA clearance. 4. Deoxycholate caused protrusion of the luminal cell surface and an increase of exfoliation of epithelial cells. The epithelial continuity was preserved. The only change induced by cholera toxin was an enhanced mucus extrusion. 5. Our results are consistent with the view that deoxycholate causes fluid secretion by filtration whereas cholera toxin enhances the secretory activity of the epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00502580
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  • 6
    Electronic Resource
    Electronic Resource
    Indirect effects of bradykinin on ion transport in rat colon descendens: mediated by prostaglandins and enteric neurons (1988)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 337 (1988), S. 69-73 
    Details
    ISSN: 1432-1912
    Keywords: Rat colon ; Ion transport ; Bradykinin ; Prostaglandins ; Tetrodotoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of bradykinin on two preparations of rat colon descendens was examined. In a mucosa-submucosa preparation consisting of the submucosal plexus, the mucosal plexus and the epithelium bradykinin (10−10-5 × 10−9 mol · 1−1) caused an increase in Isc, Gt and Pd which was to more than 70% diminished by TTX. However, in a mucosa preparation consisting of only the mucosal plexus and the epithelium bradykinin caused an increase in Isc, Gt and Pd, which was not affected by TTX. Ten times higher concentrations of bradykinin were needed in the mucosa preparation to reach the same effects as in the mucosasubmucosa preparation. All effects of bradykinin were markedly reduced in the presence of indometacin indicating that they were mediated by prostaglandins in both preparations. The bradykinin effect in the mucosa-submucosa preparation but not in the mucosa preparation was reduced about 50% by atropine. The results suggest that bradykinin activates prostaglandin synthesis. Prostaglandins subsequently stimulate neurons in the submucosal plexus which induce a secretory response on the epithelium partially mediated by a muscarinic receptor. In a high concentration bradykinin due to the induction of prostaglandin synthesis can also activate directly the mucosal epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169479
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  • 7
    Electronic Resource
    Electronic Resource
    Storage of glycogen in rat colonic epithelium during induction of secretion and absorption in vitro (1990)
    Springer
    Cell & tissue research 261 (1990), S. 195-203 
    Details
    ISSN: 1432-0878
    Keywords: Intestine (large) ; Glycogen ; Electrolyte transport ; Electric field stimulation ; Forskolin ; Tetrodotoxin ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes induced in the ultrastructure of the epithelium of the rat colon descendens by long-term electric field stimulation (EFS) in an Ussing chamber were investigated. The anion secretion, which was induced by EFS and was measured by the short-circuit current, fell continuously during a 5 h stimulation. At the end of the stimulation period, small particles were observed in the epithelium; these did not appear in unstimulated control tissue. They were localized predominantly in the apical part of the cell. By staining with periodic acidthiosemicarbazide-silver proteinate and because of their sensitivity to α-amylase, they were identified as glycogen deposits. This storage of glycogen was time-dependent and was first visible after an EFS of 2 h. It did not appear if glucose was substituted in the bathing solution by sodium butyrate. Glycogen particles were also observed after addition of forskolin, which in contrast to EFS causes a high secretory activity that is stable over several hours. The surface cells contained significantly more glycogen than the crypt cells when secretion was stimulated by EFS or forskolin. The formation of glycogen during EFS was not prevented by tetrodotoxin (TTX). In contrast, TTX itself, which causes maximal absorptive activity by blocking secretomotor neurons, induced the appearance of glycogen in the enterocytes without EFS. However, in the presence of TTX, the amount of glycogen was the same in surface and crypt cells. The results demonstrate that the capacity to synthesize and store glycogen, which has up to now only been observed in embryonic or tumor epithelial cells, is still present in adult colonic mucosa. Procedures carried out to change the functional state of the epithelium seem to induce, at least in vitro, a disinhibition of this capacity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00329452
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