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  • 1
    Electronic Resource
    Electronic Resource
    Ca2+- and swelling-induced activation of ion conductances in bronchial epithelial cells (1994)
    Springer
    Pflügers Archiv 428 (1994), S. 597-603 
    Details
    ISSN: 1432-2013
    Keywords: Cl− conductance ; K+ conductance ; ATP ; Bradykinin ; Histamine ; Bronchial epithelial cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The present study was performed to examine Ca2+-dependent and cell-swelling-induced ion conductances in a polarized bronchial epithelial cell line (16HBE14o-). Whole-cell currents were measured in fast and slow whole-cell patch-clamp experiments in cells grown either on filters or on coated plastic dishes. In addition the transepithelial voltage (V te) and resistance (R te) were measured in confluent monolayers. Resting cells had a membrane voltage (V m) of −36±1.1 mV (n=137) which was mainly caused by K+ and Cl− conductances and to a lesser extent by a Na+ conductance. V te was apical-side-negative after stimulation. Equivalent short-circuit current (I sc = V te/R te) was increased by the secretagogues histamine (0.1 mmol/l), bradykinin (0.1–10 μmol/l) and ATP (0.1–100 μmol/l). The histamine-induced I sc was blocked by either basolateral diphenhydramine (0.1 mmol/l, n=4) or apical cimetidine (0.1 mmol/l, n=4). In fast and slow whole-cell recordings ATP and bradykinin primarily activated a transient K+ conductance and hyperpolarized V m. This effect was mimicked by the Ca2+ ionophore ionomycin (1 μmol/l, n=11). Inhibition of the bradykinin-induced I sc by the blocker HOE140 (1 μmol/l, n=3) suggested the presence of a BK2 receptor. The potency sequence of different nucleotide agonists on the purinergic receptor was UTP ≈ ATP 〉 ITP 〉 GTP ≈ CTP ≈ [β,γ-methylene] ATP ≈ 2-methylthio-ATP = 0 and was obtained in I sc measurements and patch-clamp recordings. This suggests the presence of a P2u receptor. Hypotonic cell swelling activated both Cl− and K+ conductances. The Cl− conductance was only slightly inhibited by 4,4′-diisothiocyanatostilbene-2,2′-disulphonic acid (0.5 mmol/ l, n=3). These data indicate that 16HBE140- bronchial epithelial cells, which are known to express high levels of cystic fibrosis transmembrane conductance regulator protein, form a secretory epithelium. While hypotonic cell swelling activates both K+ and Cl− channels, the Ca2+-induced Cl− secretion is due mainly to activation of basolateral K+ channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00374583
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  • 2
    Electronic Resource
    Electronic Resource
    Die Gastrektomie nach Longmire im Tiermodell: Postoperative Veränderungen bei der Fettresorption sowie der Hormone Cholezystokinin und Sekretin (1994)
    Springer
    Langenbeck's archives of surgery 379 (1994), S. 271-279 
    Details
    ISSN: 1435-2451
    Keywords: Gastrectomy ; Rats ; Lipid metabolism ; CCK ; Secretin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Im Tierversuch wurde die Resorption von freien Fettsauren und Triglyzeriden nach Gastrektomie untersucht. Die Antwort der gastrointestinalen Hormone Cholezystokinin und Sekretin wurde nach einer definierten enteralen Fettbelastung mit Lipofundin MCT 20% gemessen. Die Fettresorption untersuchten wir an 3 Versuchsgruppen, die sich anatomisch (Vorhandensein bzw. Fehlen des Magens) und hinsichtlich des Ortes der Fettapplikation (intragastral bzw. intraduodenal) unterschieden. Die Verabreichung einer Testmahlzeit unter Umgehung des Magens bewirkte hinsichtlich des Fettstoffwechsels eine verzögerte Resorption der Fettsäuren, bei den gastrektomierten Tieren resultierte zusätzlich eine vermehrte Triglyzeridresorption. Mittel- und langkettige Fettsäuren setzten bei der Ratte einen adäquaten Reiz zur Stimulation der gastrointestinalen Hormone CCK und Sekretin. Bei den Gastrektomierten zeigte sick eine generelle Hormonhypersekretion im Nüchternzustand. Dem Ausbleiben der zu erwartenden CCK-Antwort auf den Fettreiz stand eine voll erhaltene Sekretinstimulierbarkeit auf angehobenem Niveau gegenüber. Die Gewichtsentwicklung der gastrektomierten Tiere war deutlich beeinträchtigt, eine konstante Gewichtszunahme auf niedrigem Niveau über den einjährigen Untersuchungszeitraum hinweg wurde konstatiert. Veränderungen in der Morphologie und Quantität der CCK-Zellen im Duodenum konnten ausgeschlossen werden.
    Notes: Abstract In this animal study we investigated the absorption of free fatty acids and triglycerides after gastrectomy. The levels of the hormones cholecystokinin and secretin were measured in response to a controlled enteral fat load (Lipofundin 20% MCT emulsion). We studied fat absorption in three groups of animals: the gastrectomy group in which lipid emulsion was administered in the duodenum, and two groups of controls that received the same infusion in the duodenum or stomach, respectively. Infusing the fat load directly into the duodenum, rather than the stomach, resulted in delayed absorption of fatty acids. In the gastrectomized animals there was, in addition, increased absorption of triglycerides. Medium- and long-chain fatty acids were found to be an adequate stimulus for secretion of the gastrointestinal hormones cholecystokinin (CCK) and secretin. In the gastrectomized group, higher baseline levels of both CCK and secretin were observed. CCK showed no response to the lipid stimulus, whereas a secretin response was observed over and above the raised baseline level. The gastrectomized animals showed a markedly restricted growth rate, as measured by body weight; however, they continued to gain weight in a linear fashion up to the end of the study period. No alterations in morphology of CCK-secreting cells were found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186392
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    Paper (German National Licenses)
    Fulltext
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