Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Properties of an anion-selective channel from rat colonic enterocyte plasma membranes reconstituted into planar phospholipid bilayers (1987)
    Springer
    The journal of membrane biology 95 (1987), S. 47-54 
    Details
    ISSN: 1432-1424
    Keywords: intestine ; epithelial transport ; chloride channels ; selectivity ; inactivation ; bilayer reconstitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Vesicles derived from epithelial cells of the colonic mucosa of the rat were fused to planar phospholipid bilayer membranes, revealing spontaneously switching anion-conducting channels of 50 pS conductance (at-30 mV with 200mm Cl− each side). The equilibrium selectivity series was I− (1.7)/Br− (1.3)/Cl− (1.0)/F− (0.4)/HCO 3 − (0.4)/Na (〈0.11.). Only one dominant open-state conductance could be resolved, which responded linearly to Cl− concentrations up to 600mm. The singlechannel current-voltage curve was weakly rectifying with symmetrical solutions. When 50 mV were exceeded at the highconductance branch of the curve, switching was arrested in the closed state. At more moderate voltages (±40 mV) kinetics were dominated by one open state of about 35-msec lifetime and two closed states of about 2 and 9-msec lifetime. Of these, the more stable closed state occurred less often. At these voltages one additional closed state of significantly longer lifetime (〉0.5 sec) was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01869629
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The Excitatory Amino Acid Receptors: Their Classes, Pharmacology, and Distinct Properties in the Function of the Central Nervous System (1989)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Pharmacology 29 (1989), S. 365-402 
    Details
    ISSN: 0362-1642
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.pa.29.040189.002053
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    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
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Neuronally mediated and direct effects of prostaglandins on ion transport in rat colon descendens (1988)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 337 (1988), S. 74-78 
    Details
    ISSN: 1432-1912
    Keywords: Rat colon ; Ion transport ; Prostaglandin E2 ; Iloprost ; Cholinergic nerves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two preparations of rat colon descendens were used in order to localize the action sites of iloprost and prostaglandin E2 (PGE2). One preparation, the mucosa-submucosa preparation contained the submucosal and mucosal plexus whereas for the mucosa preparation in addition the submucosa with the submucosal plexus was removed. Iloprost (10−6 mol · 1−1) caused an increase in short-circuit current (Isc), potential difference (Pd) and tissue conductance (Gt) of the mucosa-submucosa preparation reflecting net Cl− secretion as confirmed by unidirectional ion flux measurements. The Cl− secretion was due to an increase in J infsm supCl and a decrease in J infms supCl . These effects were completely abolished by addition of 5 × 10−5 mol · l−1 atropine. Iloprost had only small and inconsistent effects in the mucosa preparation. In contrast PGE2 (10−6 mol · l−1) increased Isc, Pd and Gt due to Cl− secretion in both preparations. The Cl− secretion was caused by an increase in J infsm supCl and a decrease in J infms Cl Only the PGE2 effect in the mucosa-submucosa preparation but not in the mucosa preparation was inhibited by about 50% by atropine. The results suggest that the prostacyclin derivative iloprost induces a Cl− secretion only by an activation of submucosal neurons whereas PGE2 acts both on the epithelium and the submucosal plexus. The neuronal effects of prostaglandins appear to be, at least in part, mediated by muscarinic receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00169480
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The role of the paracellular pathway in the net transport of calcium across the colonic muscosa (1986)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 334 (1986), S. 525-530 
    Details
    ISSN: 1432-1912
    Keywords: Colon ; Calcium transport ; Dexamethasone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Concentration dependent calcium fluxes across the colon descendens of the rat were measured in a modified Ussing chamber. Mucosa (m) to serosa (s) calcium flux showed a saturable component, whereas s to m calcium flux was linearly related to the calcium concentration. At low calcium concentrations net absorption and at concentration above 2.5 mmol/l net secretion of calcium was observed. The results obtained from the unidirectional calcium fluxes when clamping the transepithelial electrical potential agree well with those of the concentration dependence of the calcium fluxes: (1) Only m to s flux has a voltage independent component. (2) Calcium s to m movement is totally voltage dependent. (3) Diffusional s to m calcium flux is greater than the diffusional fraction of the m to s calcium flow. Dexamethasone, known to stimulate water absorption in the colon descendens by an activation of sodium transport, had no effect on the cellular mediated m to s calcium transport but significantly increased paracellular s to m flux parallel to that of the extracellular marker mannitol. This increase in paracellular s to m calcium and mannitol flux was completely abolished by amiloride, which is known to suppress the dexamethasone-induced stimulation in sodium and water absorption. The results demonstrate that the increased paracellular s to m calcium and mannitol flow is oppositely directed to the dexamethasone-induced net fluid movement as it could be expected on the basis of Ussing's “anomalous solvent drag” effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00569396
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The effect of aniline derivatives on absorption of fluid, glucose and sodium in isolated duodenal segments from rats (1986)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 334 (1986), S. 531-535 
    Details
    ISSN: 1432-1912
    Keywords: Paracetamol ; Rat duodenum ; Fluid absorption ; Glucose absorption ; Sodium absorption ; Phlorizin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Paracetamol (5–15 mmol · l−1), phenacetin (1–3 mmol · l−1) and acetanilide (5–20 mmol · l−1) enhanced fluid, glucose and sodium absorption of isolated duodenal segments from rats. In a high concentration paracetamol (30 mmol · l−1) and acetanilide (25 mmol · l−1) inhibited these parameters. The coupling coefficeint of 2:1 in sodium-glucose cotransport was not changed under the influence of the aniline derivatives. Phlorizin (10−5 mol · l−1) completely abolished the stimulatory effect of these drugs. Also in presence of 3-O-methylglucose instead of glucose in the perfusion medium a paracetamol dependent increase in fluid absorption was seen, whereas the absorption of mannitol was unchanged. The results suggest, that the increase in sodium and fluid absorption caused by aniline derivatives is due to the stimulation of active glucose transport. A cytotoxic effect may explain the decrease of absorption at high concentrations of these substances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00569397
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Forskolin induced chloride secretion across the isolated mucosa of rat colon descendens (1983)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 323 (1983), S. 355-360 
    Details
    ISSN: 1432-1912
    Keywords: Forskolin ; Chloride secretion ; Rat colon ; Electrolyte transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of forskolin, a diterpene reported to stimulate adenylate cyclase, on electrolyte transport across the isolated colonic mucosa of rat colon descendens were investigated. Forskolin, over a concentration range of 10−7–10−5 M, dose-dependently increased short circuit current (Isc) and transmural potential differences (Vms). The nearly 2-fold increase in Isc and Vms caused by forskolin was accompanied by a small increase in transmural conductance (Gt). The effects of forskolin were rapid and completely reversible without any loss in tissue sensitivity. Forskolin (5x10−6 M) inhibited the absorption of Na+ and reversed Cl− absorption to secretion. These effects were due to an inhibition of the mucosal-to-serosal fluxes of Na+ and Cl−. Ion substitution experiments revealed that the effects of forskolin were both Na+ and Cl− dependent and these ions were required in the serosal solution. Furosemide (10−4 M) as well as scilliroside (10−4 M) reversed and prevented the increase in Isc caused by forskolin. Adenylate cyclase activity in homogenates of colonic mucosa was increased 3-fold by forskolin. These results with rat colon are compared with those reported for rabbit colon and ileum and the mechanism of cyclic-AMP induced Cl− secretion in these epithelia is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00512476
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...